ArticleLiterature Review

Ocean Acidification and Its Potential Effects on Marine Ecosystems

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Ocean acidification is rapidly changing the carbonate system of the world oceans. Past mass extinction events have been linked to ocean acidification, and the current rate of change in seawater chemistry is unprecedented. Evidence suggests that these changes will have significant consequences for marine taxa, particularly those that build skeletons, shells, and tests of biogenic calcium carbonate. Potential changes in species distributions and abundances could propagate through multiple trophic levels of marine food webs, though research into the long-term ecosystem impacts of ocean acidification is in its infancy. This review attempts to provide a general synthesis of known and/or hypothesized biological and ecosystem responses to increasing ocean acidification. Marine taxa covered in this review include tropical reef-building corals, cold-water corals, crustose coralline algae, Halimeda, benthic mollusks, echinoderms, coccolithophores, foraminifera, pteropods, seagrasses, jellyfishes, and fishes. The risk of irreversible ecosystem changes due to ocean acidification should enlighten the ongoing CO(2) emissions debate and make it clear that the human dependence on fossil fuels must end quickly. Political will and significant large-scale investment in clean-energy technologies are essential if we are to avoid the most damaging effects of human-induced climate change, including ocean acidification.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Fossil fuels and cement production account for approximately 48% of the world's global Carbon emissions [52]. In addition, deforestation, industrialization and land-use-changes have led to the unprecedented increase in Carbon emissions over the past 200 years [15]. ...
... Ocean acidification is the change in ocean chemistry driven by the oceanic uptake of Carbon [15]. It is characterised by a series of chemical reactions initiated when CO 2 is absorbed by seawater. ...
... Ocean acidification has significant negative impacts on fundamental bio-ecological ocean processes [30,52]. More alarmingly, past extinction events have been linked to ocean acidification [15], and the current rate of change in seawater chemistry is unprecedented [52]. ...
Article
Full-text available
The impact of chemical processes in ocean surface waters is far-reaching. Recently, increased significance has been placed on the concentration of Carbon and its compounds and the effects these may have on climate change. Remote-sensing enables near real-time measurement of key sea-surface data which can be used to estimate Carbon levels. We illustrate with the use of hybrid Satellite sensor data. To validate our results we use data collected from cruise ships as the ground truth when training our algorithms. The error rate of our predictor is found to be small and hence the proposed approach can be used to estimate Carbon levels in any ocean. This work improves upon previous research in many ways including the use of sea water salinity as a proxy for Carbon estimates. Binary combinations of typically unary predictor attributes are used for the purposes of predicting the Carbon content of surface water and an inherently non-linear model is used to quantify the relationship.
... Algae and seagrasses are primary producers and perform photosynthesis, where CO2 is absorbed and fixed for growth, like in terrestrial plants (Hill et al., 2015) and could potentially benefit from higher CO2 conditions in oceans, primarily through increased photosynthetic rates (Duarte et al., 2017;Guinotte and Fabry 2008;Koch et al., 2012). In addition to benefitting from the effects of ocean acidification, studies have shown that algae and other primary producers can mitigate the effects of climate change (Hill et al., 2015;Chung et al., 2011;Sondak et al., 2017;Duarte et al., 2017). ...
... These threats have increased over recent years and cause injury to organisms and environment degradation or loss. The continual rise of anthropogenic atmospheric carbon dioxide, as a result of the burning of fossil fuels, industrialization, deforestation, and other land-use changes(Guinotte and Fabry 2008), will create new threats and worsen established impacts on coastal ecosystems. TheseThe oceanic absorption of carbon dioxide makes oceans more acidic due to the presence of excess of hydrogen ions. ...
Article
Some coastal ecosystems are defined as being carbon sinks for their ability to absorb more carbon than they release as a result of their high primary productivity. There has been support for the claim that macroalgal communities can act as carbon sinks and reduce levels of CO2in seawater through photosynthesis and potentially mitigate some local effects of climate change (Chung et al., 2011; Chung et al., 2013; Hill et al., 2015; Sondak et al., 2017). Within the state of Maine, rocky intertidal zones are coastal ecosystems that are particularly vulnerable to climate change and dominated by Ascophyllum nodosum (rockweed) communities (Fong 2008; Letcher 2015). The objective of this study was to evaluate the ability of rockweed to act as a carbon sink in the Gulf of Maine and mitigate local effects of climate change. The hypothesis for this experiment was photosynthesis, not respiration, would be the dominant process observed in treatments with rockweed present. Productivity was estimated through calculating the departure from oxygen saturation of each treatment.Three habitat complexity treatments were observed: a control with only salt water, rockweed submerged in salt water, and rockweed and invertebrates submerged in salt water. It was predicted the rockweed treatment would have the highest productivity, seconded by the invertebrate and rockweed treatment, and the control treatment would experience neither productivity nor respiration. Results showed little to no oxygen was produced during either trial in any treatment, suggesting that respiration was the dominant process in the experiment. This experiment does not support the claim that rockweed has the ability to act as a carbon sink. Other literature contradicts these findings which suggests this experiment would benefit from replication or further expansion.
... Climate changes had attracted a research priory due to ocean acidification and urge us to use green-energy sources. The most important challenge of research is to identify the key marine species that has enough and boundless tolerance and adaptation capability against the global climatic change (Vaijayanthi and Vijayakumar, 2014; Guinotte and Fabry, 2008). In the present study, the physico-chemical factor including pH, Electrical conductivity, Macronutrients (organic carbon, nitrogen, phosphorus, and potassium), Micronutrients (iron, manganese, zinc, copper) and others Caution exchange capacity, Magnesium and Sodium were analyzed in the soil. ...
Article
Full-text available
The intense research on marine sources have brought many potential candidates that spanning variety of industries such as in various industries, such as baking, brewing, wine, bioethanol and pharmaceutical protein production. However, only little attention has been given to marine yeasts. The present study aimed to isolate the marine soil yeasts for the production of industrial important enzymes. Soil samples were collected from Dhanushkodi (9.152011°N 79.445851°E), Ramanathapuram Dist. Tamil Nadu was collected and screened for physiochemical parameters such as electron conductivity nitrogen, total phosphorous, total potassium, total calcium, magnesium, zinc, copper, iron and manganese and organic carbon etc., The yeast strains were isolated from the soil using Yeast Mannitol agar medium and biochemically they were identified. Screening for industrial important enzymes such as amylase, extracellular and L-asparaginase was done. The marine soil samples showed pH as 7.89 and the physiochemical properties similar to the previous studies. Totally six different types of yeast were isolated and showed white, red, yellow, white creamy and pale yellow pigmentation respectively. They were identified biochemically. The Saccharomycese sp. produced all of the three enzymes viz., amylase, L-Asparaginase and protease. Edomycosis sp. showed L-Asparaginase production only activity. The L-Asparaginase enzyme is produced by yeast strain of 2.4 IU/ml of Endomycosis sp. 2.8 IU/ml of Saccharomyces sp. and S. cerevisiae of 5.6 IU/ml. The isolated marine yeasts have great potential to be applied in various industries.
... Le changement climatique transforme les écosystèmes marins à différentes échelles spatiale et temporelle et à travers toutes ses composantes (Worm et Lotze, 2016;Lotze et al., 2019) : paramètres physico-chimiques (Guinotte et Fabry, 2008), températures (Doney et al., 2012), courants (Palter, 2015), productivité primaire (Taucher et Oschlies, 2011;Moore et al., 2018) et biodiversité. Ces modifications des écosystèmes sont autant de pressions évolutives auxquelles sont soumis les organismes marins (Bellard et al., 2012). ...
Thesis
Les effets actuels du changement climatique dû aux émissions de gaz à effets de serre, sur les écosystèmes et les sociétés sont indéniables. La France dispose de nombreux gisements lui permettant de développer les Energies Marines Renouvelables, et notamment les parcs éoliens, afin d’opérer une transition énergétique. L’objectif de cette thèse est de mettre en place une approche écosystémique estimant les effets combinés de l’implantation d’un parc éolien flottant dans le Golfe de Gascogne et du changement climatique. Premièrement, un modèle de distribution spatiale des espèces a servi à projeter la niche écologique potentielle des espèces de poissons et de céphalopodes du Golfe de Gascogne, ainsi que des espèces subtropicales non indigènes, indiquant une modification des communautés marines. Puis, plusieurs modèles Ecopath ont été mis en place pour projeter les conséquences de ces arrivées sur le réseau trophique actuel, illustrant de nombreux impacts. Enfin, une spatialisation de ces deux premières parties a été réalisée grâce au module Ecospace, pour simuler l’implantation d’un parc éolien flottant, avec ses effets sur la faune marine (i.e. effet récif, effet DCP et effet réserve), dans un écosystème déjà soumis au changement climatique. Les résultats indiquent des effets positifs sur la faune marine à l’intérieur du parc.
... Equally, changes in water pH mainly depend on CO 2 fluxes through photosynthesis, bicarbonate decomposition, freshwater influx, salinity, and temperature, as well as organic matter degradation ( Rajasegar et al., 2002 ). pH fluctuation may also have negative impacts on the metabolism and growth rate of marine organisms ( Guinotte and Fabry, 2008 ). Furthermore, temperature, salinity, and pH in tandem are known to affect seawater chemistry directly, as well as buffering capacity and elevated CO 2 in estuarine systems ( Dickinson et al., 2012 ;Lannig et al., 2010 ;Nikinmaa, 2013 ). ...
Article
Full-text available
Salinity and pH play a fundamental role in structuring spatial patterns of physical properties, biota, and biogeochemical processes in the estuarine ecosystem. In this study, the influence of salinity-pH gradient and carbonate system on polychaete diversity in Ennore, Uppanar, Vellar, and Kaduvaiyar estuaries was investigated. Water and sediment samples were collected from September 2017 to August 2018. Univariate and multivariate statistical analyses were employed to define ecological status. Temperature, Salinity, pH, and partial pressure of carbon-di-oxide varied between 21 and 30°C; 29 and 39 ppt; 7.4 and 8.3; and 89.216 and 1702.558 µatm, respectively. PCA and CCA results revealed that DO, chlorophyll, carbonate species, and sediment TOC have a higher influence on polychaete community structure. Forty-two species such as Ancistrosyllis parva, Cossura coasta, Eunice pennata, Euclymene annandalei, Lumbrineris albidentata, Capitella capitata, Prionospio cirrifera, P. pinnata, P. cirrobranchiata, and Notomastus sp. were found dominantly in all estuaries. Shannon index values ranged between 1.619 (UE-1) and 3.376 (VE-2). Based on these findings, high levels of carbonate species and low pH have a greater impact on polychaete diversity and richness values. The results of the AMBI Index revealed that stations UE-1, UE-2, UE-3 in Uppanar, EC-1, EC-2 in Ennore indicate “moderately disturbed”, while other stations are under the “slightly disturbed” category. This trend was quite evident in M-AMBI as well.
... How will climate change affect ocean currents (e.g., Hu et al., 2020) and regional climates (e.g., Pershing et al., 2015)? How will ocean acidification progress and what will its impacts be (e.g., Fabry et al., 2008;Guinotte et al., 2008;Sunday et al., 2017)? Which coral reefs will survive this century (e.g., Hughes et al., 2018Hughes et al., , 2019? ...
Preprint
Full-text available
Climate change projections are central to fisheries and aquatic conservation research, and to planning for a warming world. Projections require assumptions about future emissions pathways and climate-system sensitivity to emissions. Fisheries and aquatic conservation research typically uses emissions scenarios created for the Intergovernmental Panel on Climate Change (IPCC). However, recent climate research and global development trends have significantly changed our understanding of the ranges of plausible emissions pathways to 2100 and climate sensitivities. Here, we provide a concise review of these developments, and we make recommendations for climate change scenario use in fisheries and aquatic conservation research. Although emissions pathways are uncertain, recent research suggests that emissions scenarios producing a range of approximately 3.4-4.5W/m^2 radiative forcing by 2100 might be most plausible. This corresponds to approximately 2-3 degrees C global warming by 2100 with median climate sensitivities, or 1.5-4 degrees C considering climate-sensitivity uncertainties. In terms of the Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs), plausible scenarios mostly fall between SSP2-3.4 and SSP2-4.5/RCP4.5, though higher- and lower-emissions scenarios (e.g., RCP2.6 and RCP6.0) might be plausible and should be explored in research. However, we argue that uses of high-emission scenarios (RCP8.5/SSP5-8.5, SSP3-7.0) should come with clear rationales and appropriate caveats to ensure results are not misinterpreted by scholars, policymakers, and media. We analyze fisheries and aquatic conservation papers from 2015-2021 in four major journals, and find RCP8.5 is the most commonly used scenario. These studies predominantly project quantitative, rather than qualitative, differences between RCP4.5 and RCP8.5 impacts.
... The Abereke estuary showed distinct alkaline pH values (7.49-8.06) from the other stations, which may arise from enhanced carbonate ions utilized for shell-building from the marine organisms in the estuary (Guinotte and Fabry, 2008). Another important factor is the influence of tidal currents in the study area. ...
Article
Spatial distributions and risk assessment of heavy metals (HM) and polycyclic aromatic hydrocarbon (PAH) in water and sediments of two southwestern Nigeria estuaries (Awoye A1-A6 and Abereke: AB1-AB7 and the adjoining coastal waters: I1–I12, C1–C7) were investigated. The physicochemical characteristics were measured in situ, while the HM and PAH were determined using atomic absorption spectrophotometer and gas chromatography coupled with flame ionization detection. The physicochemical characteristics of the water body were within the World Health Organization and United State Environmental Protection Agency stipulated limits for coastal water, except for pH (<6) and dissolved oxygen (<5 mg/l) attributed to a high level of human activities at the impacted stations (I1–I12). The HM in the water samples were within the permissible limits for coastal water bodies except for high Pb values (>1 mg/l) at the Awoye estuary linked to point source effluents of petroleum spills from downstream petroleum transportation. The calculated sediment contamination factor (CF) for HM indicated a considerable (3 < CF < 6) contamination of Cu (CF–Cu) at the sampling stations. Whereas the CF-Cr were within the moderate contamination range (1< CF < 3). The pollution load index (PLI) and ecological risk index (RI) suggest low-risk pollution of heavy metals to the aquatic ecosystems. The assessment of PAH revealed a dominant high molecular weight PAH composition in both surface water and sediments, mainly dominated by 4–6 rings PAH. The PAH diagnostic ratio BaA/(Ba + Chry) and IP/(IP + BghiP) points to the mixed (pyrogenic and petrogenic) origin of PAH across the two tropical estuaries and the coastal waters.
... CCA play a number of vitally important roles for corals. CCA cement and stabilise the reef substratum (Guinotte and Fabry 2008) which provides stable and suitable habitat for juvenile corals to settle on. However, reef pavement (solid carbonate substratum covered with CCA, turf algae and other sessile invertebrates), has been found to have dissolution rates 86% higher in acidified compared to ambient conditions. ...
Article
Full-text available
Ocean acidification (OA) is a major threat to marine calcifying organisms. This manuscript gives an overview of the physiological effects of acidification on reef-building corals from a cellular to population scale. In addition, we present the first review of the indirect effects resulting from altered species interactions. We find that the direct effects of acidification are more consistently negative at larger spatial scales, suggesting an accumulation of sub-lethal physiological effects can result in notable changes at a population and an ecosystem level. We identify that the indirect effects of acidification also have the potential to contribute to declines in coral cover under future acidified conditions. Of particular concern for reef persistence are declines in the abundance of crustose coralline algae which can result in loss of stable substrate and settlement cues for corals, potentially compounding the direct negative effects on coral recruitment rates. In addition, an increase in the abundance of bioeroders and bioerosive capacity may compound declines in calcification and result in a shift towards net dissolution. There are significant knowledge gaps around many indirect effects, including changes in herbivory and associated coral–macroalgal interactions, and changes in habitat provision of corals to fish, invertebrates and plankton, and the impact of changes to these interactions for both individual corals and reef biodiversity as structural complexity declines. This research highlights the potential of indirect effects to contribute to alterations in reef ecosystem functions and processes. Such knowledge will be critical for scaling-up the impacts of OA from individual corals to reef ecosystems and for understanding the effects of OA on reef-dependent human societies.
... Le changement climatique augmentera également la fréquence et l'intensité des précipitations, ce qui intensifiera les flux d'eau douce et de nutriments vers les zones côtières, entrainant à la fois une baisse de la salinité et une hausse des nutriments disponibles, affectant les phanérogames marines présentes dans les zones estuariennes (Villazán et al., 2015). Dans certaines études les herbiers figurent comme les moins impactés, voire bénéficiaires de l'acidification des océans en raison de la disponibilité accrue de CO2 et de bicarbonate pour la photosynthèse (Guinotte et Fabry, 2008 ;Koch et al., 2013 ;Kroeker et al., 2013 ;Brodie et al., 2014). Ainsi, l'acidification des océans pourrait contribuer à une baisse des substances phénoliques protectrices des feuilles des phanérogames marines et estuariennes, engendrant par conséquent une augmentation de la pression d'herbivorie, des taux de décomposition et de la mortalité chez ces plantes . ...
Thesis
Les herbiers marins constituent des habitats remarquables et diversifiés des eaux côtières des territoires ultramarins français. Une meilleure compréhension de leur état écologique sous l’influence des perturbations multiples auxquels ils sont soumis est nécessaire pour répondre aux enjeux des politiques publiques environnementales s’appliquant à l’échelle de ces territoires. Divers paramètres représentant la plupart des compartiments biologiques, allant de la physiologie des phanérogames marines à l’écosystème ont été testés in situ dans des conditions environnementales contrastées. Ces expérimentations ont permis d’évaluer les relations pressions-état des herbiers de différents territoires dans les trois océans et de sélectionner les descripteurs les plus pertinents selon les principaux objectifs de gestion. Sur la base des données collectées, une première version d’indicateurs intégrés combinant des indicateurs d'alerte précoce et de diagnostic (nutriments et certains métaux traces) et des paramètres de réponse à long terme (densité des plants et recouvrement) adaptés aux échelles de temps de la gestion ont été développés. Une première classification de l’état des herbiers étudiés est ainsi proposée. Ces outils intégrés devraient permettre de renforcer l’efficacité des mesures de gestion, tout en facilitant une mise en oeuvre mutualisée des différentes politiques publiques. L'évaluation de l'état de santé des herbiers marins et de leur environnement est essentielle afin de déployer des mesures de gestion et de préservation appropriées pour améliorer de manière durable l’état et la résilience de cet écosystème menacé.
... While the role of salinity and temperature in structuring macrofauna communities is generally well understood (Ritter et al. 2005;Beseres Pollack et al. 2009;Palmer and Montagna 2015;Van Diggelen and Montagna 2016), the mechanism for the response to pH is less well known. Fluctuations in pH can affect marine organisms in various ways including reductions in metabolism and growth, solubility of calcium carbonates, and bioavailability of metals (Knutzen 1981;Guinotte and Fabry 2008), which may have contributed to variability in soft sediment macrofauna community. ...
Article
Biogenic reefs provide important ecological functions and services to coastal and marine environments, supplying high levels of biodiversity, providing refuge and foraging habitat, and supporting fisheries. Serpulid reefs are a relatively uncommon habitat in coastal ecosystems globally that provide habitat for a diverse community of organisms, and have become a target for conservation and management efforts due to habitat degradation and loss. Baffin Bay, Texas, USA, is known for exceptionally productive commercial and recreational fisheries that are thought to be supported by Serpulid reef benthic macrofauna, particularly during regular periods of hypersalinity. This study compared the functioning of Serpulid reef habitats with nearby soft sediment areas using quantitative faunal and food web analyses. Serpulid reefs support a unique benthic macrofaunal community with 191 times greater abundance, 97 times greater biomass, and twice the number of species than in soft sediments. In contrast to soft-sediment macrofauna, Serpulid reef macrofaunal abundance and biomass were not correlated with any measured water quality variables. Isotope compositions of both suspension and deposit-feeding macrofauna from both habitats (i.e., Serpulid reefs and soft sediments) were close to organic matter from the sediment, demonstrating connectivity and the importance of primary production in the sediment to both habitat types. Abundant macrofauna inhabiting Serpulid reefs likely serve as an important food source for sport fish and other higher trophic-level fauna, particularly in hypersaline periods when soft-sediment macrobenthic food resources are scarce. Given the substantial loss of Baffin Bay’s Serpulid reef habitat compared to historic levels, conservation actions may be warranted to protect and restore Serpulid habitat and food resources. The results of this study can be used to increase the success of such efforts.
... In the Southern Ocean (SO), rapid changes are expected in the carbonate chemistry of the water, due to low temperatures and low carbonate ion saturation levels, which are already lower than in temperate regions (Guinotte and Fabry, 2008;McNeil and Matear, 2008;Midorikawa et al., 2012;Xue et al., 2018). As early as 2030, the SO is predicted to become undersaturated with aragonite, according to the RCP8.5 scenario (IPCC-SROCC 2019), a situation unlikely to have occurred in at least the last 800,000 years (Lüthi et al., 2008). ...
Article
Benthic organisms of the Southern Ocean are particularly vulnerable to ocean acidification (OA), as they inhabit cold waters where calcite-aragonite saturation states are naturally low. OA most strongly affects animals with calcium carbonate skeletons or shells, such as corals and mollusks. We exposed the abundant cold-water coral Malacobelemnon daytoni from an Antarctic fjord to low pH seawater (LpH) (7.68 ± 0.17) to test its physiological responses to OA, at the level of gene expression (RT-PCR) and enzyme activity. Corals were exposed in short- (3 days) and long-term (54 days) experiments to two pCO2 conditions (ambient and elevated pCO2 equaling RCP 8.5, IPCC 2019, approximately 372.53 and 956.78 μatm, respectively). Of the eleven genes studied through RT-PCR, six were significantly upregulated compared with control in the short-term in the LpH condition, including the antioxidant enzyme superoxide dismutase (SOD), Heat Shock Protein 70 (HSP70), Toll-like receptor (TLR), galaxin and ferritin. After long-term exposure to low pH conditions, RT-PCR analysis showed seven genes were upregulated. These include the mannose-binding C-Lectin and HSP90. Also, the expression of TLR and galaxin, among others, continued to be upregulated after long-term exposure to low pH. Expression of carbonic anhydrase (CA), a key enzyme involved in calcification, was also significantly upregulated after long-term exposure. Our results indicated that, after two months, M. daytoni is not acclimatized to this experimental LpH condition. Gene expression profiles revealed molecular impacts that were not evident at the enzyme activity level. Consequently, understanding the molecular mechanisms behind the physiological processes in the response of a coral to LpH is critical to understanding the ability of polar species to cope with future environmental changes. Approaches integrating molecular tools into Antarctic ecological and/or conservation research make an essential contribution given the current ongoing OA processes.
... For example, many phytoplankton species are positively affected by OA as their productivity, growth rate, and carbon sequestration increasing significantly (Rost et al. 2008, Beardall et al. 2009, Basu and Mackey 2018. Conversely, reduced pH and CO 3 2can pose a substantial challenge for marine calcifiers that build their skeletons from calcium carbonate and for species which are sensitive to higher proton levels during photosynthesis (Guinotte and Fabry 2008, Comeau et al. 2013, Kottmeier et al. 2016. ...
Article
The amount of CO2 absorbed by the oceans continues to rise, resulting in further acidification, altering some functional traits of phytoplankton. To understand the effect of elevated partial pressures of CO2 (pCO2) on functional traits of dinoflagellates Alexandrium affine and A. pacificum, the cardinal temperatures and chain formation extent were examined under two pCO2 (400 and 1,000 μatm) over the range of temperature expected to be associated with growth. The growth rate and chain formation extent of A. affine increased with higher pCO2, showing significant changes in cardinal temperatures and a substantial increase in middle chain-length (4‒8 cells) fractionation under elevated pCO2 condition. By contrast, there were no significant differences in specific growth rate and any chain-length fractionation of A. pacificum between ambient and elevated pCO2 conditions. The observed interspecies variation in the functional traits may reflect differences in ability of species to respond to environmental change with plasticity. Moreover, it allows us to understand the shifting biogeography of marine phytoplankton and predict their phenology in the Korea Strait.
... This CO 2 increases ocean acidity and decreases ocean pH in a process commonly referred to as "ocean acidification" (Caldeira and Wickett 2003). The addition of CO 2 to the ocean causes a decrease in carbonate ions, thus lowering calcium carbonate saturation states, making it more difficult for organisms to produce calcium carbonate shells or skeletons Guinotte and Fabry 2008). Since the beginning of the industrial era, the pH of open-ocean surface waters has decreased by about 0.1 pH units, equivalent to an overall increase of ~30% in the hydrogen ion concentration. ...
... Addition of excess amount of CO 2 in the ocean leads to overall shift in the seawater acid-base chemistry tending toward more acidic condition, reducing pH and saturation state of carbonate minerals (Hurd et al., 2019;Downey-Wall et al., 2020). Subsequent increase in carbonic acid reduces the availability of carbonate ions in oceans, thus affecting marine organisms that depend on ocean carbonate levels to form their calcium carbonate shells Guinotte and Fabry, 2008;Cooley et al., 2009;Thomsen et al., 2018;Hurd et al., 2019). Ocean acidification studies revealed both positive and negative effects on marine organisms (Kroeker et al., 2010(Kroeker et al., , 2011. ...
Article
Full-text available
Elevated carbon dioxide levels in ocean waters, an anthropogenic stressor, can alter the chemical equilibrium of seawater through a process called ocean acidification (OA). The resultant reduction of pH can be detrimental during the early developmental stages of the commercially important edible Pacific oyster Crassostrea gigas ; the ability of larvae to join a population is likely to be compromised by declining ocean pH. Given this threat, it is important to study the molecular mechanisms that these organisms use to overcome OA stress at the gene expression level. Here, we performed transcriptome profiling in oyster larvae following exposure to ambient (8.1) and reduced (7.4) pH during the pre-settlement growth period (i.e., 18 d post fertilization) using RNA-seq with Illumina sequencing technology. In total, 1,808 differentially expressed genes (DEGs) were identified, 1,410 of which were matched by BLAST against the Swiss-Prot database. Gene ontology classification showed that most of these DEGs were related to ribosomal, calcium ion binding, cell adhesion and apoptotic processes. Pathway enrichment analysis revealed that low pH (7.4) enhanced energy production and organelle biogenesis but prominently suppressed several immune response pathways. Moreover, activation of the MAPK signaling pathway was observed along with inhibition of the Wnt, VEGF, and ErbB pathways, highlighting the fact that the initiation of stress responses is given priority over larval development or shell growth when the larvae cope with low pH. In conclusion, our study demonstrated a unique gene expression profiling approach in studying oyster larval responses to OA, which not only provides comprehensive insights into the mechanisms underlying oyster tolerance to CO 2 -driven decreases in ocean pH but also supplies a valuable genomic resource for further studies in this species.
... These effects have an influence on epipelagic ecosystem species, particularly those that sustain high-value commercial fisheries, either directly or through trophic interactions. Physiological changes have been used in the past to infer the ecological consequences of ocean acidification Guinotte & Fabry, 2008;Widdicombe &Spicer 2008 andDupont et al., 2010). ...
... Since organic detritus are consuming by several species, most of the freshwater ecologists have broadly divided such consumers into functional feeding groups [13]. Fluctuating pH may compromise the optimal associated life processes (such as metabolism and growth) as well as potentially improve calcium carbonate solubility and the metal bioavailability [24,42]. Salinity variations typically exhibit tremendous effects on the structure and functioning of aquatic ecosystems across all environmental variables. ...
Article
Full-text available
The integrity of the homestead pond supply depends on how various macrobenthic communities make their living more diversified and contribute to complex food webs. In addition, the macrobenthic community are significantly used as indicator organisms to detect the pollution impacts in aquatic ecosystems. In this study, we show the data about the diversity and community structure of macrobenthos and their relationship with environmental variables in homestead ponds of Noakhali coast from January 2019 to August 2019. The current study yielded 17 species belonging to seven taxonomic groups with a mean density of 3630 ind./m2. The Nematode community, comprising 48.86% of the total taxonomic groups with Prionchulus sp. as the dominant macrobenthic species represented more than 31% of the total macrobenthic taxa, and showed a significant negative correlation with the value of salinity, DO, pH. The environmental variables and diversity indices were detected significant variations (P < 0.05) among stations by the Kruskal-Wallis ANOVA, whereas Shannon-Wiener Diversity Index (H´) assessed moderate pollution, Evenness index (J) assessed uniform distributions of macrobenthic community, and environmental variables showed acceptable condition for the productivity of ponds. Cluster analysis (CA) and Non-metric multidimensional scaling (nMDS) demonstrate demarcations in the community structure of macrobenthos between samples. Within macrobenthic communities, Canonical Correspondence Analysis (CCA) provided insights and interpretations of the relationships between species and environmental gradients. Macrobenthic community reached the most abundance at a lower temperature, transparency and a higher DO, pH and salinity.
... De estas dos formas biológicas de CaCO 3 , el aragonito presenta el doble de solubilidad que la calcita pura, sin embargo, la calcita alta en magnesio es más soluble que el aragonito, por lo que es la forma más sensible a la acidificación . Por lo tanto, en un futuro próximo la acidificación de los océanos tendrá un impacto generalizado tanto en las especies marinas como en los ecosistemas Guinotte y Fabry 2008;Hoegh-Guldberg et al. 2008;Hendriks et al. 2010;Porzio et al. 2011;Ragazzola et al. 2012;Mostofa et al. 2016) con graves consecuencias para los millones de personas que dependen de los ecosistemas costeros, la pesca y la acuicultura (Hall-Spencer y Harvey 2019). ...
Article
Full-text available
La futura acidificación de los océanos tendrá un impacto generalizado en las especies marinas y los ecosistemas. Las algas coralinas (Corallinophycidae, Rhodophyta) son elementos conspicuos de las comunidades litorales en todas las latitudes. En la pared celular de las algas coralinas interviene la forma más soluble de calcita, lo que las hace particularmente vulnerables a variaciones en el pH del mar. En esta síntesis discutimos el actual conocimiento sobre las algas coralinas de Canarias en el contexto de los avances producidos en las últimas décadas tanto en la taxonomía (aplicación de diferentes criterios taxonómicos) como en la ecología (un grupo de organismos que prestan unos servicios ecosistémicos muy valiosos). En Canarias las algas coralinas están actualmente representadas por 56 especies, pero existen fundadas razones para creer que es una subestimación del número real de especies. Participan en la mayoría de las comunidades litorales y su abundancia permite considerarlas como elementos característicos de numerosos hábitats, algunos de ellos escasamente investigados.
... For example, high temperature and low pH led to a significant decrease in shell hardness in oyster Crassostrea virginica and clam Mercenaria mercenaria (Ivanina et al., 2013). Low pH leads to a decrease of carbonate ions in seawater, impacting the ability to build shells and alter the shells mechanical properties (Pörtner et al., 2005;Guinotte and Fabry, 2008;Doney et al., 2009;Ramajo et al., 2013;Fitzer et al., 2014;Milano et al., 2016;Leung et al., 2017a). ...
Article
Environmental variation alters biological interactions and their ecological and evolutionary consequences. In coastal systems, trematode parasites affect their hosts by disrupting their life-history traits. However, the effects of parasitism could be variable and dependent on the prevailing environmental conditions where the host-parasite interaction occurs. This study compared the effect of a trematode parasite in the family Renicolidae (metacercariae) on the body size and the shell organic and mechanical characteristics of the intertidal mussels Perumytilus purpuratus, inhabiting two environmentally contrasting localities in northern and central Chile (ca. 1600 km apart). Congruent with the environmental gradient along the Chilean coast, higher levels of temperature, salinity and pCO2, and a lower pH characterise the northern locality compared to that of central Chile. In the north, parasitised individuals showed lower body size and shell resistance than non-parasitised individuals, while in central Chile, the opposite pattern was observed. Protein level in the organic matter of the shell was lower in the parasitised hosts than in the non-parasitised ones regardless of the locality. However, an increase in polysaccharide levels was observed in the parasitised individuals from central Chile. These results evidence that body size and shell properties of P. purpuratus vary between local populations and that they respond differently when confronting the parasitism impacts. Considering that the parasite prevalence reaches around 50% in both populations, if parasitism is not included in the analysis, the true response of the host species would be masked by the effects of the parasite, skewing our understanding of how environmental variables will affect marine species. Considering parasitism and identifying its effects on host species faced with environmental drivers is essential to understand and accurately predict the ecological consequences of climate change.
... Marine organisms are permanently exposed to multiple stressors, such as climate changes [1][2][3] and the consequential ocean acidification, deoxygenation and sea-level rise [4][5][6], natural toxic metabolites [7][8][9][10][11] and compounds deriving from human activities [12][13][14][15]. The exposure to these stressors induces marine organisms to adopt strategies against external or internal environmental factors through metabolic and/or molecular changes to maintain cellular homeostasis [16,17]. ...
Article
Full-text available
Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) represent the most common pollutants in the marine sediments. Previous investigations demonstrated short-term sublethal effects of sediments polluted with both contaminants on the sea urchin Paracentrotus lividus after 2 months of exposure in mesocosms. In particular, morphological malformations observed in P. lividus embryos deriving from adults exposed to PAHs and PCBs were explained at molecular levels by de novo transcriptome assembly and real-time qPCR, leading to the identification of several differentially expressed genes involved in key physiological processes. Here, we extensively explored the genes involved in the response of the sea urchin P. lividus to PAHs and PCBs. Firstly, 25 new genes were identified and interactomic analysis revealed that they were functionally connected among them and to several genes previously defined as molecular targets of response to the two pollutants under analysis. The expression levels of these 25 genes were followed by Real Time qPCR, showing that almost all genes analyzed were affected by PAHs and PCBs. These findings represent an important further step in defining the impacts of slight concentrations of such contaminants on sea urchins and, more in general, on marine biota, increasing our knowledge of molecular targets involved in responses to environmental stressors.
... Otolith elemental incorporation can vary with the morphological development of otoliths and physiological processes of fish, both of which are sensitive to pH changes in seawater (Campana, 1999;Munday et al., 2011a;Heuer and Grosell, 2014). Additionally, the pH level of seawater can directly affect the chemical properties of elements and may consequently alter otolith elemental incorporation (Guinotte and Fabry, 2008). To date, only four studies have addressed this topic, and the studied species included larval clownfish (Munday et al., 2011a), juvenile walleye pollock and barramundi (Hurst et al., 2012;Martino et al., 2017) and six wild adult fish species (Mirasole et al., 2017). ...
Article
Full-text available
Ocean acidification can influence the formation, development and functions of calcified structures in marine organisms, such as otoliths, which are mainly composed of calcium carbonate (CaCO3) and function in orientation, balance, sensory perception and locomotion in fish. This study investigated the impacts of seawater acidification (pH 8.10, 7.70 and 7.30, roughly corresponding to the ocean acidification under RCP 8.5 scenario predicted by the IPCC) on somatic growth, otolith (aragonite) morphology and microchemistry in the flounder Paralichthys olivaceus at early life stages (ELSs, exposed to acidified seawater via pCO2 from embryonic to juvenile stages for 52 days). The results demonstrated that seawater acidification promoted otolith growth (mass and size) but did not change their geometric outlines. Seawater acidification did not alter the somatic growth or otolith elemental incorporation (Sr, Ba and Mg) in the flounder. Seawater acidification increased the occurrence of abnormally developed calcitic otoliths (calcite) which considerably differed from the aragonitic otoliths in surface and crystal structures. Additionally, elemental incorporation (Sr:Ca and Ba:Ca) appeared to be higher in aragonitic otoliths than in calcitic otoliths, which was likely related to their unique manners of formation. Our results agreed with the broad literature, in that seawater acidification showed species-specific influences (positive or no effect) on otolith size but did not affect somatic growth, otolith shape or elemental incorporation of fish at ELSs. These findings provide knowledge for evaluating the ecological effects of ocean acidification on the recruitment and population dynamics of fish in the wild.
... As CO 2 is absorbed, the saturation state of aragonite and calcite lowers, hindering the formation of these minerals and facilitating their dissolution. That leads to slower calcifying rates and the weakening of the structures of calcifying organisms, which become more prone to erosion damage (Guinotte and Fabry, 2008;Pimentel et al., 2014). Corals, echinoderms and mollusks, for example, are becoming increasingly more vulnerable, which results in less food availability for fish and deterioration of coral reefs that serve as their habitat. ...
Article
Full-text available
A mechanistic model based on Dynamic Energy Budget (DEB) theory was developed to predict the combined effects of ocean warming, acidification and decreased food availability on growth and reproduction of three commercially important marine fish species: white seabream (Diplodus sargus), zebra seabream (Diplodus cervinus) and Senegalese sole (Solea senegalensis). Model simulations used a parameter set for each species, estimated by the Add-my-Pet method using data from laboratory experiments complemented with bibliographic sources. An acidification stress factor was added as a modifier of the somatic maintenance costs and estimated for each species to quantify the effect of a decrease in pH from 8.0 to 7.4 (white seabream) or 7.7 (zebra seabream and Senegalese sole). The model was used to project total length of individuals along their usual lifespan and number of eggs produced by an adult individual within one year, under different climate change scenarios for the end of the 21st century. For the Intergovernmental Panel on Climate Change SSP5–8.5, ocean warming led to higher growth rates during the first years of development, as well as an increase of 32–34% in egg production, for the three species. Ocean acidification contributed to reduced growth for white seabream and Senegalese sole and a small increase for zebra seabream, as well as a decrease in egg production of 48–52% and 14–33% for white seabream and Senegalese sole, respectively, and an increase of 4–5% for zebra seabream. The combined effect of ocean warming and acidification is strongly dependent on the decrease of food availability, which leads to significant reduction in growth and egg production. This is the first study to assess the combined effects of ocean warming and acidification using DEB models on fish, therefore, further research is needed for a better understanding of these climate change-related effects among different taxonomic groups and species.
... For example, nutrient run-off results in eutrophication with the ensuing breakdown of organic matter produced by phytoplankton blooms causing high pCO 2 and reduced pH values, adding to the acidification caused by anthropogenic CO 2 uptake (Wallace et al., 2014;Zhao et al., 2020). The acidification of estuarine and coastal waters is affecting ecosystems negatively and various biogeochemical processes in a water column (Guinotte and Fabry, 2008;Hall et al., 2020;Thomas et al., 2022). For example, enhanced acidic conditions threaten the growth, abundance, and survival of shell-forming organisms (corals, some plankton species, and commercial shellfish (Doney et al., 2020;Fox et al., 2020;Wilson et al., 2020;Blaisdell et al., 2021) and affect the solubility and speciation of trace metals (Millero et al., 2009;Hoffmann et al., 2012). ...
Article
Full-text available
High quality pH measurements are required in estuarine and coastal waters to assess the impacts of anthropogenic atmospheric CO2 emissions on the marine carbonate system, including the resulting decrease in pH. In addition, pH measurements are needed to determine impacts on carbonate chemistry of phytoplankton blooms and their breakdown, following enhanced anthropogenic nutrient inputs. The spectrophotometric pH technique provides high quality pH data in seawater, and is advantageous for long-term deployments as it is not prone to drift and does not require in situ calibration. In this study, a field application of a fully automated submersible spectrophotometric analyzer for high-resolution in situ pH measurements in dynamic estuarine and coastal waters is presented. A Lab-on-Chip (LOC) pH sensor was deployed from a pontoon in the inner Kiel Fjord, southwestern Baltic Sea, for a total period of 6 weeks. We present a time-series of in situ pHT (total pH scale) and ancillary data, with sensor validation using discretely collected samples for pHT and laboratory analysis. The difference between the sensor and laboratory analyses of discrete samples was within ±0.015 pHT unit, with a mean difference of 0.001 (n=65), demonstrating that the LOC sensor can provide stable and accurate pHT measurements over several weeks.
... In addition to ocean warming, ocean acidification (OA) is going to be one of the most important threats to benthic habitats (Constable et al., 2014). The SO is prone to faster acidification because its low surface water temperature facilitates increased CO 2 solubility and greater upwelling of CO 2 -rich bottom water (Guinotte and Fabry, 2008). Although a very limited amount of specific literature is available, tit has shown that OA will positively influence the bacterial community of the SO, whereas it will cause dissolution of skeleton, hinder reproductive success, and shorter life history stages in benthic organisms (Byrne, 2011;Ericson et al., 2012;Hancock et al., 2020). ...
Chapter
The Southern Ocean (SO) benthic biodiversity is the reflection of major geological events and climate change. This remote marine realm, dominated by glacial cycles and Antarctic Circumpolar Current (ACC), is home to diverse benthic communities. Peculiar biotic and abiotic conditions prevailing in the SO have steered its benthic components towards key ecological adaptations. The disjunctive pattern witnessed in the distribution of the benthic fauna has resulted from vicariance during the separation of Gondwana. High endemism found in the SO and Antarctic benthic assemblages have resulted from their evolution in long isolation. Moreover, the thermal gradient in water current acts as a determinant of the dispersal and connectivity of the species lineages. Due to distinct trait modalities, the responses of SO benthic species to environmental changes differ considerably from those of species living in other ecosystems. The SO biome is prone to habitat alteration mediated by global climate change, which in turn has a cascading effect on the benthic biota, from the level of the genes to that of the community. It is therefore crucial to understand the benthic responses to climate change through the networks of biotic interactions. Our understanding of the benthic biodiversity of SO and Antarctic region has improved immensely since the advent and application of modern molecular biological techniques. Additionally, Convention for Conservation of Antarctic Marine Living Resources has strengthened the conservation policies by designating and prioritizing important ecological zones as Marine Protected Areas and Vulnurable Marine Ecosystems. However, more integrated ecosystem studies and networking models are required to fill the knowledge gap and improve our understanding of the benthic biome of the SO and Antarctic regions. This review summarizes the current state of knowledge on the benthic biodiversity of SO, apprises the evolutionary history that shaped the endemism of the SO benthos, and finally points out the potential threats of climate change on the biogeochemistry and ecosystem functioning in the SO.
... phytoplancton ; Lohbeck et al., 2012). Les résultats obtenus suggèrent que ces modifications de la chimie des océans auront des conséquences importantes sur les taxons marins (Guinotte and Fabry, 2008). Tous les niveaux de la chaîne trophique alimentaire seront impactés, ce qui aura également des effets sur la survie des post-larves, puisque les organismes phytoplanctoniques constituent les premiers maillons de cette chaine. ...
Thesis
Ce travail de thèse s’inscrit dans le cadre de deux programmes de recherche à financements européens: le Life+ SUBLIMO(Life10 NAT/FR/000200) vise à analyser, suivre et restaurer la biodiversité marine en Méditerranée et Ressources Halieutiques/Post-larves(75/SAEU/FEDER/RD-34 448)quia pour objectif d'évaluer les impacts de certains facteurs environnementaux sur cette biodiversité. Dans le cadre de ces travaux, nous avonsdéveloppéune nouvelle méthode d’identification (APLIM: Alive Post Larvae Identification Method)permettant d’aller jusqu'à la détermination desespèces pour les post-larvesde poissons, ce qui est novateurpour les taxons méditerranéens. Cette méthode regroupe différents outils: collecte de post-larvesvivantes, mise en bassin d’élevage, suivis photographiques, définition descaractèresméristiques, morphologiques et pigmentaires. Laméthode fournitles fiches de 80 espèces identifiées au stade post-larvaire, valorisées par la publication d'un Atlas regroupant ces fiches.Cet Atlaspermet ainsi d’apporter de nouvelles connaissances,essentiellement au niveau des techniques de pêche, d’identification mais également d’élevage en bassinsaquacoles, qui seront utiles aux professionnels de la mer (pêcheurs, aquaculteurs, gestionnaires) pour la gestion durable des ressources halieutiques et le maintien de la biodiversité marine. Ce guide vise à être un outil pour une meilleure gestion des futurs stocks halieutiques. Les assemblages spécifiques de biodiversité post-larvairesnous indiquentles espèces les plus contributives pourchaque site. Par ailleurs,nous avons remarquéla présence ubiquiste de Mullus surmuletus.Des variations spatio-temporelles ont mis en exerguedesdifférences entre la zone continentaleet la zone corse, mais également une saisonnalité marquée,surtout en été, grâce notamment à l’élaboration des calendriers d’arrivées des individussur les littoraux. Cependant, la déterminationdes habitats d’installation préférentiels en zone côtière demeure complexe et les mécanismes qui la régissentrestent encore à définir.Nous avons pu observer une succession trophique des troiscompartiments décrits (phytoplancton, zooplanctonetpost-larves).Par la suite, nous avonstestéles interactions entre ces différents compartiments et déterminéles relations proies/prédateurs possibles entre les groupes caractérisés. Les analyses par ADN barcodingdes contenus stomacaux desfamilles principalement rencontréesont permis de déterminer les différents régimes alimentairesdes post-larves de poissons côtiers.Les paramètres environnementaux qui semblent le plus influencer les arrivées sur les côtes corses sont la température, les vents et les courants côtiers.
... Yet, the importance of this AOM carbon pump and of its potential implications for ocean pH and carbon emissions in response to future methane hydrate destabilisation remains unconstrained [47,56]. In particular, and similar to what is expected to result from increases of atmospheric carbon dioxide, pH decrease resulting from hydrate destabilisation may impact many marine organisms and biological processes [57][58][59][60], including composition of communities and food webs, alter ocean atmospheric carbon dioxide uptake [61,62], and increase the toxicity of certain heavy metals and organic pollutants [63]. ...
Article
Full-text available
Modern observations and geological records suggest that anthropogenic ocean warming could destabilise marine methane hydrate, resulting in methane release from the seafloor to the ocean-atmosphere, and potentially triggering a positive feedback on global temperature. On the decadal to millennial timescales over which hydrate-sourced methane release is hypothesized to occur, several processes consuming methane below and above the seafloor have the potential to slow, reduce or even prevent such release. Yet, the modulating effect of these processes on seafloor methane emissions remains poorly quantified, and the full impact of benthic methane consumption on ocean carbon chemistry is still to be explored. In this review, we document the dynamic interplay between hydrate thermodynamics, benthic transport and biogeochemical reaction processes, that ultimately determines the impact of hydrate destabilisation on seafloor methane emissions and the ocean carbon cycle. Then, we provide an overview of how state-of-the-art numerical models treat such processes and examine their ability to quantify hydrate-sourced methane emissions from the seafloor, as well as their impact on benthic biogeochemical cycling. We discuss the limitations of current models in coupling the dynamic interplay between hydrate thermodynamics and the different reaction and transport processes that control the efficiency of the benthic sink, and highlight their shortcoming in assessing the full implication of methane release on ocean carbon cycling. Finally, we recommend that current Earth system models explicitly account for hydrate driven benthic-pelagic exchange fluxes to capture potential hydrate-carbon cycle-climate feed-backs.
... Recent studies document that some marine species including coleoids such as Sepia are more resistant to rising acidity than others (e.g., Gutowska et al., 2010;Ries et al., 2009). Studies about corals (Veron, 2008), foraminifers (Guinotte & Fabry, 2008), calcified nannoplankton (Erba et al., 2010) and echinoderms show a severe impact of ocean acidification on many marine calcifiers. These insights have led some authors to conclude that ocean acidification may result in metabolic depression followed by reduced growth (Michaelidis et al., 2005), reduced calcification rates (Hautmann, 2006), hypermetabolism (Michaelidis et al., 2007), or a simultaneous increase of calcification rate and metabolic rates . ...
Article
Full-text available
The impact of increasing atmospheric CO2 and the resulting decreasing pH of seawater are in the focus of current environmental research. These factors cause problems for marine calcifiers such as reduced calcification rates and the dissolution of calcareous skeletons. While the impact on recent organisms is well established, little is known about long-term evolutionary consequences. Here, we assessed whether ammonoids reacted to environmental change by changing septal thickness. We measured the septal thickness of ammonoid phragmocones through ontogeny in order to test the hypothesis that atmospheric pCO2, seawater pH and other factors affected aragonite biomineralisation in ammonoids. Particularly, we studied septal thickness of ammonoids before and after the ocean acidification event in the latest Triassic until the Early Cretaceous. Early Jurassic ammonoid lineages had thinner septa relative to diameter than their Late Triassic relatives, which we tentatively interpret as consequence of a positive selection for reduced shell material as an evolutionary response to this ocean acidification event. This response was preserved within several lineages among the Early Jurassic descendants of these ammonoids. By contrast, we did not find a significant correlation between septal thickness and long-term atmospheric pCO2 or seawater pH, but we discovered a correlation with palaeolatitude. Supplementary information: The online version contains supplementary material available at 10.1186/s13358-022-00246-2.
... Planktic foraminifera and pteropods are the major zooplankton producers of CaCO 3 and a key component of the ocean carbon cycle (Guinotte and Fabry, 2008). Besides coccolithophores (unicellular phytoplankton), they have an important role in exporting carbon from the surface to the deep ocean. ...
Article
Full-text available
Planktic foraminifera and shelled pteropods are some of the major producers of calcium carbonate (CaCO 3 ) in the ocean. Their calcitic (foraminifera) and aragonitic (pteropods) shells are particularly sensitive to changes in the carbonate chemistry and play an important role for the inorganic and organic carbon pump of the ocean. Here, we have studied the abundance distribution of planktic foraminifera and pteropods (individuals m –3 ) and their contribution to the inorganic and organic carbon standing stocks (μg m –3 ) and export production (mg m –2 day –1 ) along a longitudinal transect north of Svalbard at 81° N, 22–32° E, in the Arctic Ocean. This transect, sampled in September 2018 consists of seven stations covering different oceanographic regimes, from the shelf to the slope and into the deep Nansen Basin. The sea surface temperature ranged between 1 and 5°C in the upper 300 m. Conditions were supersaturated with respect to CaCO 3 (Ω > 1 for both calcite and aragonite). The abundance of planktic foraminifera ranged from 2.3 to 52.6 ind m –3 and pteropods from 0.1 to 21.3 ind m –3 . The planktic foraminiferal population was composed mainly of the polar species Neogloboquadrina pachyderma (55.9%) and the subpolar species Turborotalita quinqueloba (21.7%), Neogloboquadrina incompta (13.5%) and Globigerina bulloides (5.2%). The pteropod population was dominated by the polar species Limacina helicina (99.6%). The rather high abundance of subpolar foraminiferal species is likely connected to the West Spitsbergen Current bringing warm Atlantic water to the study area. Pteropods dominated at the surface and subsurface. Below 100 m water depth, foraminifera predominated. Pteropods contribute 66–96% to the inorganic carbon standing stocks compared to 4–34% by the planktic foraminifera. The inorganic export production of planktic foraminifera and pteropods together exceeds their organic contribution by a factor of 3. The overall predominance of pteropods over foraminifera in this high Arctic region during the sampling period suggest that inorganic standing stocks and export production of biogenic carbonate would be reduced under the effects of ocean acidification.
... The oceanic acidification, which is another change predicted by the IPCC, may affect cellular processes, physiology, and the behavior of marine organisms impacting their survival, growth, and reproduction (Guinotte & Fabry, 2008;Gazeau et al., 2013). This is not different in estuaries; however, the environment response is faster compared to other marine environments (Marshall et al., 2016). ...
Article
Full-text available
Climate change has been considered as the most serious threat to biodiversity, and therefore, it has been receiving increasing attention regarding its potential impacts on the coastal zone. According to IPCC forecasts, increase in CO2, sea and air temperature, sea level rise, and ocean acidification are expected. Thus, this study evaluated the synergistic effect of future climate changes in Littorinids from temperate and tropical estuarine environments through experimental studies. Mortality, changes in size, weight loss, and specie’s behaviors of the species Littorina fabalis and Littorina littorea in Spain and Littoraria angulifera and Litteraria flava in Brazil were evaluated in the laboratory considering estuarine acidification, temperature increase, and salinity variations due to sea level rise and/or rainfall reduction. The data presented indicate that estuarine Littorinids will respond to climate change as (i) with increased mortality rates, weight loss, and changes in behavior as a function of increased temperatures, and, (ii) with decreased shell sizes resulting from the dissolution of the shell apex due to estuarine acidification. These results suggest changes in these estuarine ecosystems resulting in effects that lead to serious endangerment to animal biodiversity and ecological balance.
... For instance, while branchiobdellids, which are epibionts of crayfish, act as commensals in clean water, their relationship changes to mutualism under a fouling environment [47]. The limpets and coralline algae are sensitive to ocean acidification in Antarctica because calcium carbonate (CaCO 3 ) makes up the main component of their shell [19,49]. When the temperature and pH of the seawater fluctuate due to climate change, the epibiotic relationship between limpet and coralline algae will also be affected. ...
Article
Full-text available
The Antarctic limpet, Nacella concinna, is one of the most abundant benthic marine invertebrates found in the intertidal zone of King George Island, Antarctica. The shell of N. concinna is often encrusted with the coralline algae Clathromorphum obtectulum. In this study, to reveal the relationship between the limpet and coralline algae, we examined how the coralline algae affect the physical condition (survival and health) and morphology of the limpet. We cultured the limpets for 22 days and compared mortality, weight, condition factor (CF), fatty acid content, and the structure of the shell surface between limpets both with and without coralline algae in the laboratory. We also measured the environmental factors (i.e., temperature, pH, and salinity) of the seawater at each sampling site and the CF of the limpets and correlated them with coverage of coralline algae. The presence of coralline algae significantly increased the mortality of the limpets by 40% and the shell weight by 1.4-fold but did not affect the CF. Additionally, coralline algae altered the fatty acid profiles related to the limpet’s lipid metabolism (saturated fatty acids (SFA) and some polyunsaturated fatty acids (PUFA)). Specifically, C16:0, C17:0, C18:0, and total SFA increased, whereas C18:2 and C18:3 decreased. However, observations with a scanning electron microscope showed that shell damage in limpets with coralline algae was much less than in limpets without coralline algae, suggesting that coralline algae may provide protection against endolithic algae. The area of coralline algae on the limpet shell was positively correlated with the pH and temperature of the seawater. The results suggest that although coralline algae are generally assumed to be parasitical, the relationship between N. concinna and coralline algae may change to mutualism under certain conditions.
... Nonetheless, it remains obscured what might possibly occur to the future oceanic pH (See Table 6), whilst others argue that the multiple complexity of the present humaninduced impacts on the oceanic system may not be analogues to paleo-geological similar events, thus comparisons may be made under high uncertainty (Doney et al., 2009). Despite this uncertainty, there are studies anticipating potential damage by oceanic pH decrement in the entire oceanic ecosystem: from calcifying macroalgae, cold water corals and fishery stocks, to phytoplankton and seagrasses, these changes might have irrevocable and yet unknown impacts to the entire oceanic ecosystem, altering conditions with potential dramatic results in natural geochemical cycles and marine life as we know it (Guinotte and Fabry, 2008;Guo et al., 2020). ...
Thesis
Full-text available
Available here: https://estia.hua.gr/browse/25964
... Physiological responses to CO 2 acidification, including metabolism, growth and calcification, have been reported in a wide range of aquatic species (Guinotte and Fabry 2008;Doney et al. 2009;Kroeker et al. 2010). To mitigate the negative consequences of CO 2 acidification, there is a strong selection pressure on traits for fitness and a necessity for evolutionary change (Gienapp et al. 2008;Sunday et al. 2011). ...
Article
Carbon dioxide-induced acidification of aquatic systems is predicted to pose a serious threat to aquatic biota. Although the majority of the literature has highlighted the negative effect of CO2 acidification on aquatic biota, this work focuses on potential effects of CO2 acidification, both positive and negative, on aquatic life forms and the response strategies (acclimation and adaptive) in order to cope with the acidification stressor. Both freshwater and marine waterbodies are susceptible to CO2 acidification, and there are contrasting viewpoints with respect to the sensitivity and resilience of the species under acidification conditions. Response strategies shown by aquatic life forms have the potential for ameliorating the negative effects of acidification. Therefore, understanding the mechanism of response strategies is paramount, and these strategies need to be investigated both within generations and crossgenerationally to estimate the phenotypic and genetic variations that a species underwent.
Article
Full-text available
This paper addresses the current understanding of the potential for ocean alkalinisation to sequester multi-billion tonnes of carbon as calcium bicarbonate, and at the same time both restore the ocean alkalinity and support photosynthesizing marine flora.
Article
Full-text available
Jellyfish are known to carry various epibionts, including many of the subphylum Crustacea. However, the associations between gelatinous zooplankton and other invertebrates have been chronically overlooked. Crustacea, a massive clade of economically, ecologically, and culturally important species, includes many taxa that utilize gelatinous zooplankton for food, transport, and protection as both adults and juveniles. Here we compile 211 instances of epifaunal crustaceans recorded on Hydromedusae and Scyphomedusae from a century of literature. These include 78 identified crustacean species in 65 genera across nine orders found upon 37 Hydromedusa species and 48 Scyphomedusae. The crustacean life stage, location, nature of the association with the medusa, years, months, and depths are compiled to form a comprehensive view of the current state of the literature. Additionally, this review highlights areas where the current literature is lacking, particularly noting our poor understanding of the relationships between juvenile crabs of commercially valuable species and medusae.
Article
Full-text available
We report a new, autonomous Lab-on-Chip (LOC) microfluidic pH sensor with a 6000 m depth capability, ten times the depth capability of the state of the art autonomous spectrophotometric sensor. The pH is determined spectrophotometrically using purified meta-Cresol Purple indicator dye offering high precision (<0.001 pH unit measurement reproducibility), high frequency (every 8 min) measurements on the total proton scale from the surface to the deep ocean (to 600 bar). The sensor requires low power (3 W during continuous operation or ∼1300 J per measurement) and low reagent volume (∼3 μL per measurement) and generates small waste volume (∼2 mL per measurement) which can be retained during deployments. The performance of the LOC pH sensor was demonstrated on fixed and moving platforms over varying environmental salinity, temperature, and pressure conditions. Measurement accuracy was +0.003 ± 0.022 pH units (n = 47) by comparison with validation seawater sample measurements in coastal waters. The combined standard uncertainty of the sensor in situ pHT measurements was estimated to be ≤0.009 pH units at pH 8.5, ≤ 0.010 pH units at pH 8.0, and ≤0.014 pH units at pH 7.5. Integrated on autonomous platforms, this novel sensor opens new frontiers for pH observations, especially within the largest and most understudied ecosystem on the planet, the deep ocean.
Article
Neogloboquadrina pachyderma (sinistral), the dominant planktonic foraminiferal species in the mid-to-high latitude oceans, represents a major component of local calcium carbonate (CaCO3) production. However, the predominant factors, governing the calcification of this species and its potential response to the future marine environmental changes, are poorly understood. The present study utilized an improved cleaning method for the size-normalized weight (SNW) measurement to estimate the SNW of N. pachyderma (sin.) in surface sediments from the Amundsen Sea, the Ross Sea, and the Prydz Bay in the Antarctic Zone of the Southern Ocean. It was found that SNW of N. pachyderma (sin.) is not controlled by deep-water carbonate dissolution post-mortem, and can be therefore, used to reflect the degree of calcification. The comparison between N. pachyderma (sin.) SNW and environmental parameters (temperature, salinity, nutrient concentration, and carbonate system) in the calcification depth revealed that N. pachyderma (sin.) SNWs in the size ranges of 200–250, 250–300, and 300–355 µm are significantly and positively correlated with seawater temperature. Moreover, SNW would increase by ∼30% per degree increase in temperature, thereby suggesting that the calcification of N. pachyderma (sin.) in the modern Antarctic Zone of the Southern Ocean is mainly controlled by temperature, rather than by other environmental parameters such as ocean acidification. Importantly, a potential increase in calcification of N. pachyderma (sin.) in the Antarctic Zone to produce CaCO3 will release CO2 into the atmosphere. In turn, the future ocean warming will weaken the ocean carbon sink, thereby generating positive feedback for global warming.
Chapter
Okyanus ve denizlerinizdeki en hızlı büyüyen çevresel tehdit haline gelen plastik kirliliği gezegenimizin iklimi için de ciddi bir tehdit oluşturmaktadır. Çok büyük bir kısmı fosil yakıtlardan yapılan plastikler ham maddenin çıkarılmasından, rafinerizasyonuna, geri dönüşümünden doğada son bulmasına kadar yaşam döngüsünün her aşamasında sera gazı emisyonuna yol açmaktadır. Plastik üretiminin önümüzdeki yıllarda katlanarak artacağı göz önünde bulundurulduğunda, plastikten kaynaklanan sera gazı emisyonlarının küresel sıcaklık artışını 1,5℃'nin altında tutma kabiliyetimizi tehlikeye attığı düşünülmektedir. Küresel ölçekte plastiklerin üretiminin kontrol altına alınması, plastik atıkların işlenmesi ve bertarafının iyileştirilmesi ve (mikro) plastiklerin iklim üzerindeki etkisinin değerlendirilmesi önem arz etmektedir.
Article
Full-text available
Polluted aerosol transport from South Asia containing oxides of nitrogen and sulphur and their deposition on surface may acidify coastal waters. To test this hypothesis, we have conducted experiments involving (a) variability in aerosol composition at a coastal station (Visakhapatnam, central east coast of India) during 2013–2014 (monthly) and 2015–2016 (weekly observations), and (b) simultaneous observations of aerosols over land and adjacent coastal water in winter of 2013 and 2016. The annual average composition of aerosols during this study was dominated by SO42− (48%) followed by NO3− (15%). Sulphate (~12 μg m−3) exhibited high concentrations in Fall Intermonsoon (FIM) and winter monsoon (WM), whereas higher nitrate (3–4.5 μg m−3) concentrations were observed during summer monsoon (SM) and FIM. The mean [NO3−/SO42−] ratio of 0.32 suggests that atmospheric aerosol over the study region is contributed by transportation of fossil fuel burning emissions from the subcontinent by high-altitude large-scale wind circulation. The concentrations of NO2 and SO2 varied from 17.2 to 34.3 and 11.5 to 16.4 µg m−3, respectively with mean [SO2/NO2] ratio of 0.57 and [SO42−/SO42−+SO2] ratio of 0.33 indicates coal burning (power plants/industries) and fossil fuel burning may be the major source of atmospheric dust in the study region. Comparison of total cations and anion concentrations indicate aerosols are acidic in FIM and SM and mixed nature (acidic/basic) in WM but near neutral in spring Intermonsoon (SIM). Simultaneous experiments revealed that about 5–45% of the atmospheric aerosols were deposited within 10 km from the coast. The in vitro experiments indicated that the deposition of atmospheric aerosols resulted in a measurable decrease in pH of surface seawater and displayed significant relationship between decrease in pH and concentration of NO3−/SO42−, but it was weaker with NO2/SO2 suggesting former ions contribute significantly in lowering pH of coastal waters than latter. The impact of decrease in pH on acid–base equilibrium, carbonate chemistry and gas exchanges need to be assessed.
Chapter
Global and local distribution patterns of representative marine mussel species are presented in this chapter. The major physical factors that influence marine mussel distribution and abundance are temperature, salinity and hydrographic factors, while local distribution is also influenced by temperature and salinity in addition to wave force and changes in immersion patterns, which are monitored by data loggers. Predators, pests, fouling organisms and competitors are biological factors that influence local distribution in intertidal and shallow water environments. Significant predators are whelks, crabs, sea stars, birds, sea urchins, lobsters and flatfish. The most common pests are boring sponges, polychaetes and peacrabs, while ~100 invertebrate species have been identified as fouling organisms on mussel ropes. Mussels are the most prominent competitors for space in mid‐ to low‐shore areas on gently sloping rocky shores. The final part of this chapter considers the potential and observed impacts of climate change on marine ecosystems.
Chapter
Human‐induced changes to the earth's climate have resulted in changes to marine ecosystems. Climatic impacts on a few keystone species may result in large‐scale changes in community structure and composition. This chapter focuses on the best understood and most worrisome impacts of climate change on tropical estuarine and marine biota: coral bleaching; mangrove displacement and survival in the face of sea‐level rise (SLR); ocean acidification effects on calcifying organisms, especially corals; and effects on tropical fisheries. The impact of rising temperatures on corals needs to be considered along with other climate changes, such as ocean acidification. Future survival of mangrove forests ultimately depends on the rapidity of future increases in relative SLR. The effects of ocean acidification on coral reefs can be complex and often unclear, especially when combined with other climate effects such as rising temperatures and sea level.
Chapter
This chapter focuses on two groups of animals historically classified under the phylum Coelenterata because of their shared radial symmetry and other structural similarities. It examines a cross formal taxonomic lines and considers Ctenophora and Cnidarian Scyphozoa because of their many anatomic, physiologic, and behavioral similarities. The predator comb jellies are in turn preyed upon by jellyfish, sea turtles, and some fishes. The box jellyfish are the topic of considerable taxonomic discussion. Heavy metal toxicities are documented for moon jellyfish and 200μg copper per liter leads to rapid mortality of polyps. Fungi and viruses likely infect jellyfish, but little work has been done to investigate these possibilities. Digeneans can infect jellyfish medusae as part of their complex life cycle that usually involves three hosts. Isopods have been reported as symbionts of jellyfish in the wild. Medical imaging brings immediately to mind routine radiographic films commonly associated with diagnosing broken limbs and misplaced organs.
Chapter
Climate change is a daunting problem and has only recently attracted attention. This chapter presents a review on the implications of climate change on the regulation, and modelling of toxic pollutants. Also, it identifies relationships between climate fluctuations and changes in some polluants distribution (heavy metals, hydrocarbons, and pesticides). Moreover, the influence of climate change on polluant environmental behavior is explored by studying polluants response to inter-annual climate fluctuations such as precipitation and temperature. Therefore, it will be important to monitor strategies taking into account climate change and new regulatory plans should be devised in toxics polluant management.
Article
Climate change and urbanization of coastal areas are impacting estuarine habitats globally. While these regions are important for the early-life development of many aquatic species, links between habitat use and foraging ecology are not well known. Thus, it is essential to understand the importance of threatened habitats for animals inhabiting estuaries to promote their conservation and improve ecosystem management. This study examined the importance of estuarine habitats as feeding grounds for juvenile bull sharks (Carcharhinus leucas) in the Clarence River, a nursery area where the species is targeted by commercial fisheries in New South Wales, Australia. Juvenile sharks (n = 54) ranging from one to ∼6.5 years-old, together with particulate matter and several primary producer species of mangrove and saltmarsh, were sampled for δ13C, δ15N and δ34S stable isotopes. Bayesian mixing models and a Generalized Additive Mixed Model were used to investigate the contribution of estuarine habitats to the diet of bull sharks and changes with growth. The importance of resources consumed from within mangrove habitats for juvenile bull shark resource use was minimal but slightly increased with age, with younger sharks (<2.5 years) relying on prey feeding on sources derived from particulate organic matter, while older juveniles (4–6.5 years) preyed on species that relied mostly on threatened saltmarsh habitats. Our findings highlight the important linkages between habitats of conservation concern and species redistribution in response to climate change, particularly as the animals could be moving towards new areas lacking suitable estuarine habitats.
Article
Cryptocaryon irritans is a ciliate parasite that causes “white spot disease” in marine teleosts. The disease outbreak is influenced by hosts and a range of abiotic factors, such as temperature, salinity, and pH.
Chapter
Full-text available
The present study aimed to present associations of living foraminifera (0-0.50 cm) from two locations in the Antarctic Peninsula: a shallower one, in the Antarctic Specially Managed Area (ASMA No. 1) in Admiralty Bay, off the Antarctic Station Comandante Ferraz (EACF); and another in a deeper region rich in gas hydrate, located in the Drake Passage. From the lists of species and ecological indices, statistical analyses were performed, such as t-test, KruskalWallis, Dunnet, and principal components, to find similarities between the studied regions. and complement the Census of Marine Life in Antarctica, edited by the Scientific Committee on Antarctic Research. Deuterammina grisea, Epistominella exigua, and Globocassidulina subglobosa were the three most abundant species, present in both areas. They can be considered as eubiotic spe a particular fauna and must be protected from possible human impacts. And the knowledge obtained through this research should be an incentive to achieve this goal, as well as subsidize future biomonitoring studies.
Article
Contamination of water bodies is one of the alarming concerns of today’s times calling for immediate attention and action. Accelerated industrialization and other human-driven activities have given way to abrupt spike in the carbon emissions. These carbon emissions are absorbed by the water bodies. As a resultant of this absorption, the carbon reacts with oxygen present in water, forming carbonic acid and causes the pH level of water to decrease, thus, causing water acidification. The acidity of water also increases due to discharge of wastes and pollutants into aquatic bodies. Also, the carbon induced global warming leads to an increase in the temperature of water which further leads to a decline in level of dissolved oxygen in aquatic bodies. Besides, these phenomena cause a rise in the growth of algal bloom, which depletes the dissolved oxygen concentration in water due to consumption of dissolved oxygen in algal decomposition process. To investigate these impacts of increasing acidity and rising carbon emissions on the aquatic populations, a non-linear mathematical model is proposed and analysed. Numerical simulations using MATLAB are performed in order to support the analytical results.
Article
Ocean acidification (OA) and microplastics (MPs) contamination are two results of human excises. In regions like estuarine areas, OA and MPs exposure are happening at the same time. The current research investigated the synthesized effects of OA and MPs exposure for a medium-term duration on the physiology and energy budget of the thick shell mussel Mytilus coruscus. Mussels were treated by six combinations of three MPs levels (0, 10 and 1000 items L-1) × two pH levels (7.3, 8.1) for 21 d. As a result, under pH 7.3, clearance rate (CR), food absorption efficiency (AE), respiration rate (RR), and scope for growth (SFG) significantly decreased, while the fecal organic dry weight ratio (E) significantly increased. 1000 items L-1 MPs led to decrease of CR, E, SFG and increase of AE under pH 8.1. Interactive effects from combination of pH and MPs were found in terms of CR, AE, E and RR, but not for SFG of M. coruscus.
Article
Full-text available
Carbonate chemistry of the Arctic Ocean seafloor and its vulnerability to ocean acidification remains poorly explored. This limits our ability to quantify how biogeochemical processes and bottom water conditions shape sedimentary carbonate chemistry, and to predict how climate change may affect such biogeochemical processes at the Arctic Ocean seafloor. Here, we employ an integrated data‐model assessment that explicitly resolves benthic pH and carbonate chemistry along a South—North transect in the Barents Sea. We identify the main drivers of observed carbonate dynamics and estimate benthic fluxes of dissolved inorganic carbon and alkalinity to the Arctic Ocean. We explore how bottom water conditions and in‐situ organic matter degradation shape these processes and show that organic matter transformation strongly impacts pH and carbonate saturation (Ω) variations. Aerobic organic matter degradation drives a negative pH shift (pH < 7.6) in the upper 2–5 cm, producing Ω < 1. This causes shallow carbonate dissolution, buffering porewater pH to around 8.0. Organic matter degradation via metal oxide (Mn/Fe) reduction pathways further increases pH and carbonate saturation state. At the northern stations, where Ω > 5 at around 10–25 cm, model simulations result in authigenic carbonate precipitation. Furthermore, benthic fluxes of dissolved inorganic carbon (12.5–59.5 μmol cm⁻² yr⁻¹) and alkalinity (11.3–63.2 μmol cm⁻² yr⁻¹) are 2–3‐fold greater in the northern sites due to greater carbonate dissolution. Our assessment is of significant relevance to predict how changes in the Arctic Ocean may shift carbon burial and pH buffering into the next century.
Chapter
Sediment and water samples were collected during monsoon and summer seasons for 2 years from four study sites, viz. Paradeep, Chilika, Gopalpur, and Rushikulya, along the Bay of Bengal, Odisha, India. Samples were analysed for abiotic parameters such as pH, salinity, temperature and total mercury content. Similarly, total heterotrophic bacterial load and mercury-resistant marine bacterial load were analysed in the collected samples. The pH of water samples in all the study sites varied from 6.41 ± 0.014 to 8.4 ± 0.141 during the summer season, whereas during the monsoon season it varied from 6.535 ± 0.077 to 8.55 ± 0.070. Similarly, the salinity in the study sites ranged from 9 ± 1.414 psu to 36.5 ± 0.707 psu during the summer season and 4.5 ± 0.707 psu to 34.5 ± 0.707 psu during the monsoon season. The temperature of the water also followed the same trend that varied from 26.55 ± 1.343 °C to 38.5 ± 0.141 °C in the summer season, and during the monsoon season the range was 21.85 ± 0.494 °C to 28.95 ± 0.636 °C. Sediment samples showed to contain a higher amount of mercury at Rushikulya (2.48 and 2.26 ppb) among the study sites in both seasons followed by Paradeep, Chilika and Gopalpur. Huge fractions of marine bacteria were found to be mercury resistant in nature, and a strong positive correlation (r = 0.94 and 0.93 in water and sediment samples) was obtained between mercury content and the mercury-resistant marine bacterial populations in the Bay of Bengal, India.
Article
Full-text available
Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs.
Article
Full-text available
Carbon dioxide-induced ocean acidification is predicted to have major implications for marine life, but the research focus to date has been on direct effects. We demonstrate that acidified seawater can have indirect biological effects by disrupting the capability of organisms to express induced defences, hence, increasing their vulnerability to predation. The intertidal gastro-pod Littorina littorea produced thicker shells in the presence of predation (crab) cues but this response was disrupted at low seawater pH. This response was accompanied by a marked depression in metabolic rate (hypometabolism) under the joint stress of high predation risk and reduced pH. However, snails in this treatment apparently compensated for a lack of morphological defence, by increasing their avoidance behaviour, which, in turn, could affect their interactions with other organisms. Together, these findings suggest that biological effects from ocean acidification may be complex and extend beyond simple direct effects.
Article
Full-text available
Increased concentrations of CO2 in the atmosphere will cause not only global warming but also raised partial pressure of CO2 and lowered pH in the ocean. These environment alterations may affect fish and other marine organisms. On the other hand, feasibility studies recently suggest that disposal of anthropogenic CO2 in the deep ocean could help reduce atmospheric CO2 concentrations. However, implementation of this strategy could have a significant environmental impact on marine life. These circumstances provide a background for the urgent need of further studies concerning the effect of CO2 on fish. In this paper we summarize the literature reporting on CO2 effects on fish and discuss the required research work for the future. The present knowledge from the literature is summarized and categorized into oxygen consumption rate, respiration activity, oxygen carrying capacity by red blood cells, blood gas, blood circulation, CO2 receptor, acid-base balance, endocrine, growth, toxicity and anesthesia. Most of the experimental fish used in the literature are freshwater species (carp and rainbow trout have largely been used). There were only few examined marine species (three bottom dwelling species of elasmobranch and teleost, respectively). Since experiments have only been carried out on adult fish, experiments on reproduction and the early life stage should be performed to clarify effects over the life cycle and to predict long term hypercapnic effects. Physiological studies have mostly been concerned with the acid-base balance and we need further information on maturation and endocrine to evaluate long term hypercapnic effects on fish populations. Changes in swimming behavior and its mechanism must also be examined. Although the early phase of future study on CO2 effects on fish has to start using shallow-water species, deep-sea species should be considered in concern with the disposal of CO2 in the deep ocean. Furthermore, extrapolating data from one well researched species to evaluate implications on the ecosystem as a whole would be hazardous. In order to validate an appropriate resolution to the global warming problem, a multi-disciplinary approach to the effects of CO2 disposal utilizing specialists from fields such as marine biology, fisheries and physical oceanography is clearly necessary.
Article
Full-text available
The severity of the impact of elevated atmospheric pCO(2) to coral reef ecosystems depends, in part, on how seawater pCO(2) affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO(2) and CO32- to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO(2) on calcification and dissolution processes. Rates of net calcification and dissolution, CO32- concentrations, and pCO(2) were measured, in situ, on patch reefs, bare sand, and coral rubble on the Molokai reef flat in Hawaii. Rates of calcification ranged from 0.03 to 2.30 mmol CaCO3 m(-2) h(-1) and dissolution ranged from -0.05 to -3.3 mmol CaCO3 m(-2) h(-1). Calcification and dissolution varied diurnally with net calcification primarily occurring during the day and net dissolution occurring at night. These data were used to calculate threshold values for pCO(2) and CO32- at which rates of calcification and dissolution are equivalent. Results indicate that calcification and dissolution are linearly correlated with both CO32- 3 and pCO2. Threshold pCO(2) and CO32- 3 values for individual substrate types showed considerable variation. The average pCO(2) threshold value for all substrate types was 654 +/- 195 mu atm and ranged from 467 to 1003 mu atm. The average CO32- threshold value was 152 +/- 24 mu mol kg(-1), ranging from 113 to 184 mu mol kg(-1). Ambient seawater measurements of pCO(2) and CO32- indicate that CO32- and pCO(2) threshold values for all substrate types were both exceeded, simultaneously, 13% of the time at present day atmospheric pCO(2) concentrations. It is predicted that atmospheric pCO(2) will exceed the average pCO2 threshold value for calcification and dissolution on the Molokai reef flat by the year 2100.
Article
Full-text available
Several parameters of water samples collected from Grand Bahama Bank in June 1962 and in June 1963 were measured. They include the partial pressure of CO2, the total dissolved inorganic CO2, the C14/C12 ratio in the inorganic CO2, and the CaCO3 saturation (by the Weyl saturometer). From these results absolute residence times of water on the bank up to 250 days have been computed. An average CaCO3 precipitation rate of 50 mg/cm2 yr is estimated. The rate of CaCO3 deposition is proportional to the degree of supersaturation. By elimination of 0.6 mole of CO2 for each mole of CaCO3 precipitated, the bank water maintains a nearly constant CO2 partial pressure. Combining measurements made with the Weyl saturometer with estimates of the observed activity product made it possible to estimate an activity product for aragonite of 0.80×10−8. This agrees satisfactorily with the value calculated from the free energies of the CO32− ion, Ca2+ ion, and aragonite solid. The waters come onto the bank with an activity product of 1.68×10−8. The value falls to about 0.9×10−8 for those samples residing longest on the bank. C14 measurements on material centrifuged from ‘whitings’ indicate that their turbidity results from resuspension of sediment rather than in situ precipitation. The methods used here should have broad application to problems involving shallow-water CaCO3 deposition.
Article
Full-text available
This paper reports that prior to human activities, there was a net flux of COâ from the ocean through the atmosphere to the land. This flux fueled organic production in terrestrial ecosystems. Human interference in the COâ cycle has reversed the role of the ocean as a COâ source; it is now a net sink of anthropogenic COâ. The strength of this sink is debatable. Sinks include solution of COâ in surface seawater, and the more minor processes of dissolution of carbonates, nutrient fertilization and increased organic carbon burial increased fluxes of stream-derived particulate organic carbon (POC) and dissolved organic carbon (DOC) to the oceans, and increased dissolved inorganic carbon (DIC) flux from increased weathering. We determine that the sink strength of the combined minor fluxes is roughly 760 MTCY⁻¹. Dissolution of benthically-derived carbonate skeletons may account for about 7% of this flux. The process and importance of dissolution are discussed in light of sediment trap and water carbon chemistry data from the Hawaiian Archipelago. Each minor sink taken individually may not seem important when viewed against the atmospheric COâ increase of 3000 MTCY⁻¹.
Article
Full-text available
Over the last twenty years, human exploitation has begun to have an impact in the deep sea, especially in the upper bathyal zone. This has mainly taken the form of deep-sea fishing but more recently oil exploration has extended beyond the continental shelf. Deep-water coral reefs occur in the upper bathyal zone throughout the world. These structures, however, are poorly studied with respect to their occurrence, biology and the diversity of the communities associated with them. In the North-East Atlantic the coral Lophelia pertusa has frequently been recorded. The present review examines the current knowledge on L. pertusa and discusses similarities between its biology and that of other deep-water, reef-forming, corals. It is concluded that L. pertusa is a reef-forming coral that has a highly diverse associated fauna. Associated diversity is compared with that of tropical shallow-water reefs. Such a highly diverse fauna may be shared with other deep-water, reef-forming, corals though as yet many of these are poorly studied. The main potential threats to L. pertusa in the North-East Atlantic are considered to be natural phenomena, such as slope failures and changes in ocean circulation and anthropogenic impacts such as deep-sea fishing and oil exploration. The existing and potential impacts of these activities on L. pertusa are discussed. Deep-sea fishing is also known to have had a significant impact on deep-water reefs in other parts of the world.
Article
Full-text available
[1] Fish are important members of both freshwater and marine ecosystems and constitute a major protein source in many countries. Thus potential reduction of fish resources by high-CO2 conditions due to the diffusion of atmospheric CO2 into the surface waters or direct CO2 injection into the deep sea can be considered as another potential threat to the future world population. Fish, and other water-breathing animals, are more susceptible to a rise in environmental CO2 than terrestrial animals because the difference in CO2 partial pressure (PCO2) of the body fluid of water-breathing animals and ambient medium is much smaller (only a few torr (1 torr = 0.1333 kPa = 1316 μatm)) than in terrestrial animals (typically 30–40 torr). A survey of the literature revealed that hypercapnia acutely affects vital physiological functions such as respiration, circulation, and metabolism, and changes in these functions are likely to reduce growth rate and population size through reproduction failure and change the distribution pattern due to avoidance of high-CO2 waters or reduced swimming activities. This paper reviews the acute and chronic effects of CO2 on fish physiology and tries to clarify necessary areas of future research.
Article
Full-text available
This paper presents results on the distribution, abundance, and size of Lophelia pertusa coral reefs in mid-Norway (62 degrees 30'-65 degrees 30'N) as compiled from own investigations, earlier scientific reports, reports from fishery surveys and fishermen. Detailed bathymetrical mapping covering an area of similar to 600 km(2) along the Halten gas-pipeline, and two nearby areas across the shelf revealed 70 Lophelia reefs. In general, the reefs occurred close to breaks and escarpments. High densities of up to nine reefs per km(2) were found in areas with a rugged seabed topography and with a slope >0.6 degrees. These seabed features have probably positive influence on the transport and concentration of food particles and thus control the local distribution of Lophelia. The area covered by individual reefs varied between 1230 m(2) and 37,310 m(2) with a mean of 5628 m(2). The height of the reefs was positively correlated with the area. Reefs < 10,000 m(2) had a circular outline, while larger reefs were elongate, aligned parallel to the depth contours. Along the pipeline the average density of Lophelia reefs was 0.09 km(-2) which indicates that the total number of reefs is 6300, covering similar to 35 km(2) within the whole study area.
Article
Full-text available
The oceanic uptake of anthropogenic CO2 changes the seawater chemistry and potentially can alter biological systems in the upper oceans. Estimates of future atmospheric and oceanic CO2 concentrations, based on the Intergovernmental Panel on Climate Change (IPCC) emission scenarios, indicate that atmospheric CO2 levels could approach 800 ppm by the end of the century. Corresponding models for the oceans indicate that surface water pH would decrease by approximately 0.4 pH units, and the carbonate ion concentration would decrease by as much as 48% by the end of the century. The surface ocean pH would be lower than it has been for more than 20 million years. Such changes would significantly lower the ocean's buffering capacity, which would reduce its ability to accept more CO2 from the atmosphere. Recent field and laboratory studies reveal that the carbonate chemistry of seawater has a profound impact on the calcification rates of individual species and communities in both planktonic and benthic habitats. The calcification rates of nearly all calcifying organisms studied to date decrease in response to decreased carbonate ion concentration. In general, when pCO2 was increased to twice preindustrial levels, a decrease in the calcification rate ranging from about -5% to -60% was observed. Unless calcifying organisms can adapt to projected changes in seawater chemistry, there will likely be profound changes in the structure of pelagic and benthic marine ecosystems.
Article
Full-text available
The rise in atmospheric CO2 has caused significant decrease in sea surface pH and carbonate ion (CO32-) concentration. This decrease has a negative effect on calcification in hermatypic corals and other calcifying organisms. We report the results of three laboratory experiments designed specifically to separate the effects of the different carbonate chemistry parameters (pH, CO32-, CO2 [aq], total alkalinity [AT], and total inorganic carbon [C T]) on the calcification, photosynthesis, and respiration of the hermatypic coral Acropora eurystoma. The carbonate system was varied to change pH (7.9-8.5), without changing CT; CT was changed keeping the pH constant, and CT was changed keeping the pCO2 constant. In all of these experiments, calcification (both light and dark) was positively correlated with CO32- concentration, suggesting that the corals are not sensitive to pH or CT but to the CO 32- concentration. A decrease of ∼30% in the CO 32- concentration (which is equivalent to a decrease of about 0.2 pH units in seawater) caused a calcification decrease of about 50%. These results suggest that calcification in today's ocean (pCO2 = 370 ppm) is lower by ∼20% compared with preindustrial time (pCO2 = 280 ppm). An additional decrease of ∼35% is expected if atmospheric CO 2 concentration doubles (pCO2 = 560 ppm). In all of these experiments, photosynthesis and respiration did not show any significant response to changes in the carbonate chemistry of seawater. Based on this observation, we propose a mechanism by which the photosynthesis of symbionts is enhanced by coral calcification at high pH when CO2(aq) is low. Overall it seems that photosynthesis and calcification support each other mainly through internal pH regulation, which provides CO32- ions for calcification and CO2(aq) for photosynthesis. © 2006, by the American Society of Limnology and Oceanography, Inc.
Article
Full-text available
Using the DeltaTCO2° results of Chen (1982a) obtained during a cruise in the northeast Pacific Ocean (June-July 1981), we have calculated preindustrial and 1981 calcite and aragonite saturation horizons for a transect along 150°W between Alaska and Hawaii. Uptake of excess CO2 by the oceans over the past 130 years has resulted in a significant change in the carbonate chemistry of the northeast Pacific Ocean. The results indicate an apparent reduction in the thickness of the supersaturated lenses and an upward translation of the 100% saturation level by as much as 150 meters for calcite and 70 meters for aragonite in the coldwater region north of the Subarctic Front.
Article
Full-text available
New carbonate chemistry data obtained during a 1982 cruise have been combined with earlier GEOSECS and INDOPAC data to determine the degree of aragonite saturation of surface and intermediate waters of the North Pacific. Large gradients in saturation state occur in the region of the Subarctic Front in the north-south direction and across the Subtropical Gyre in the east-west direction. These gradients are primarily due to the extensive mixing that occurs in the intermediate waters of the western North Pacific. The major variations in saturation state were primarily related to the carbonate ion concentration, which in turn, is primarily a function of mixing and biological processes. The present aragonite saturation depth at our northernmost station in the western North Pacific was calculated to be within 120 m of the surface. This result was directly corroborated by observations of aragonite dissolution under in vitro conditions. Our calculations show that one possible effect of fossil fuel-derived CO2 on the surface of the North Pacific will be a steady progression of undersaturation from the northern to southern and western areas, with the first sign of undersaturation possibly occurring as early as the second half of the next century.
Article
Full-text available
An integral part of assessing the northern Gulf of Alaska (GOA) ecosystem is the analysis of the food habits and feeding patterns of abundant zooplanktivorous fish. Juvenile pink salmon Oncorhynchus gorbuscha are highly abundant zooplanktivores, and support valuable commercial fisheries as adults. We document variability in pink salmon distribution and size from summer to early fall, and present major trends in their food habits by summarizing interannual (August 1999-2001), seasonal (July-October 2001) and diel (August 2000, and July-September 2001) feeding patterns based on analysis of stomach contents of juvenile pink salmon collected along the Seward Line (GOA) and in Prince William Sound (PWS), Alaska. Diets of juvenile pink salmon were more diverse in 2001 compared to either 1999 or 2000. Small pteropods (Limacina helicina) composed the majority (> 60%) of prey consumed in 1999 and 2000; whereas large copepods, euphausiids, and small pteropods composed the majority of prey in 2001. As juvenile pink salmon increased in size, they consumed increasingly larger prey from August to October 2001 in the GOA. The diet of GOA juvenile pink salmon was different and more diverse than the diet of fish caught in PWS. The dominant prey in PWS during July-October was hyperiid amphipods, whereas the primary prey in the GOA were larvaccans and euphausiids in July, then copepods plus small pteropods, amphipods, euphausiids, larval crabs, and shrimp in August.
Article
Full-text available
Laboratory experiments with living planktic foraminifers show that the δ13C and δ18O values of shell calcite decrease with increasing sea water pH and/or carbonate ion concentration. The effect has been quantified in symbiotic (Orbulina universa) and non-symbiotic (Globigerina bulloides) species and is independent of symbiont activity and temperature. It is concluded that a kinetic fractionation process affects both the carbon and oxygen isotopic composition of the shell simultaneously. At present it cannot be determined definitively whether the relationship is controlled by the pH dependent balance between hydration and hydroxylation of CO2 or by (CO3 2 - ) related variations in the calcification rate. However, independent of which factor ultimately controls the relationship between the carbonate chemistry and isotopic fractionation, in the real ocean (CO3 2 - ) and pH covary linearly across the relevant pH range. The true relationship between shell isotopic composition and the bulk carbonate chemistry is masked by the fact that host respiration and symbiont activity locally modify the carbonate system. Respiration lowers and photosynthesis increases ambient pH and (CO3 2 - ). This translates into modified absolute shell values but leaves the slope between the shell isotopic composition and the bulk carbonate chemistry unaffected. A se- cond level of shell isotopic modification is introduced by the incorporation of respired carbon, enriched in 12C, which depletes the shell δ13C value. In symbiont bearing species this depletion is partially negated by a shell δ13C enrichment in the light. As an alternative to the RUBISCO hypothesis (enrichment via preferential removal of 12CO2), we propose that scavenging of respired CO2 during photosynthesis, raises the shell δ13C value. Our results have partly been documented before (Spero et al. 1997) and demonstrate that the carbonate chemistry is undoubtedly a major control on temporal geochemical variability in the fossil record. For instance, the sea water carbonate system of the pre- Phanerozoic world (Berner 1994; Grotzinger and Kasting 1993) or during glacials (Sanyal et al. 1995) was significantly different from today confounding direct interpretation of foraminiferal stable isotope data using existing relationships (see companion paper in this volume by Lea et al.).
Article
Full-text available
Uptake of half of the fossil fuel CO2 into the ocean causes gradual seawater acidification. This has been shown to slow down calcification of major calcifying groups, such as corals, foraminifera, and coccolithophores. Here we show that two of the most productive marine calcifying species, the coccolithophores Coccolithus pelagicus and Calcidiscus leptoporus, do not follow the CO2-related calcification response previously found. In batch culture experiments, particulate inorganic carbon (PIC) of C. leptoporus changes with increasing CO2 concentration in a nonlinear relationship. A PIC optimum curve is obtained, with a maximum value at present-day surface ocean pCO2 levels (∼360 ppm CO2). With particulate organic carbon (POC) remaining constant over the range of CO2 concentrations, the PIC/POC ratio also shows an optimum curve. In the C. pelagicus cultures, neither PIC nor POC changes significantly over the CO2 range tested, yielding a stable PIC/POC ratio. Since growth rate in both species did not change with pCO2, POC and PIC production show the same pattern as POC and PIC. The two investigated species respond differently to changes in the seawater carbonate chemistry, highlighting the need to consider species-specific effects when evaluating whole ecosystem responses. Changes of calcification rate (PIC production) were highly correlated to changes in coccolith morphology. Since our experimental results suggest altered coccolith morphology (at least in the case of C. leptoporus) in the geological past, coccoliths originating from sedimentary records of periods with different CO2 levels were analyzed. Analysis of sediment samples was performed on six cores obtained from locations well above the lysocline and covering a range of latitudes throughout the Atlantic Ocean. Scanning electron micrograph analysis of coccolith morphologies did not reveal any evidence for significant numbers of incomplete or malformed coccoliths of C. pelagicus and C. leptoporus in last glacial maximum and Holocene sediments. The discrepancy between experimental and geological results might be explained by adaptation to changing carbonate chemistry.
Article
Full-text available
In this study we investigated the relations between community calcification of an entire coral reef in the northern Red Sea and annual changes in temperature, aragonite saturation and nutrient loading over a two year period. Summer (April–October) and winter (November–March) average calcification rates varied between 60 ± 20 and 30 ± 20 mmol·m−2·d−1, respectively. In general, calcification increased with temperature and aragonite saturation state of reef water with an apparent effect of nutrients, which is in agreement with most laboratory studies and in situ measurements of single coral growth rates. The calcification rates we measured in the reef correlated remarkably well with precipitation rates of inorganic aragonite calculated for the same temperature and degree of saturation ranges using empirical equations from the literature. This is a very significant finding considering that only a minute portion of reef calcification is inorganic. Hence, these relations could be used to predict the response of coral reefs to ocean acidification and warming.
Article
Full-text available
An investigation was conducted to determine the effects of elevated pCO2 on the net production and calcification of an assemblage of corals maintained under near-natural conditions of temperature, light, nutrient, and flow. Experiments were performed in summer and winter to explore possible interactions between seasonal change in temperature and irradiance and the effect of elevated pCO2. Particular attention was paid to interactions between net production and calcification because these two processes are thought to compete for the same internal supply of dissolved inorganic carbon (DIC). A nutrient enrichment experiment was performed because it has been shown to induce a competitive interaction between photosynthesis and calcification that may serve as an analog to the effect of elevated pCO2. Net carbon production, NPC, increased with increased pCO2 at the rate of 3 ± 2% (μmol CO2aq kg−1)−1. Seasonal change of the slope NPC-[CO2aq] relationship was not significant. Calcification (G) was strongly related to the aragonite saturation state Ωa. Seasonal change of the G-Ωa relationship was not significant. The first-order saturation state model gave a good fit to the pooled summer and winter data: G = (8 ± 1 mmol CaCO3 m−2 h−1)(Ωa − 1), r2 = 0.87, P = 0.0001. Both nutrient and CO2 enrichment resulted in an increase in NPC and a decrease in G, giving support to the hypothesis that the cellular mechanism underlying the decrease in calcification in response to increased pCO2 could be competition between photosynthesis and calcification for a limited supply of DIC.
Article
Full-text available
The effect of elevated pCO2 on the metabolism of a coral reef community dominated by macroalgae has been investigated utilizing the large 2650 m3 coral reef mesocosm at the Biosphere-2 facility near Tucson, Arizona. The carbonate chemistry of the water was manipulated to simulate present-day and a doubled CO2 future condition. Each experiment consisted of a 1–2 month preconditioning period followed by a 7–9 day observational period. The pCO2 was 404 ± 63 μatm during the present-day pCO2 experiment and 658 ± 59 μatm during the elevated pCO2 experiment. Nutrient levels were low and typical of natural reefs waters (NO3− 0.5–0.9 μM, NH4+ 0.4 μM, PO43− 0.07–0.09 μM). The temperature and salinity of the water were held constant at 26.5 ± 0.2°C and 34.4 ± 0.2 ppt. Photosynthetically available irradiance was 10 ± 2 during the present-day experiment and 7.4 ± 0.5 mol photons m−2 d−1 during the elevated pCO2 experiment. The primary producer biomass in the mesocosm was dominated by four species of macroalgae; Haptilon cubense, Amphiroa fragillisima, Gelidiopsis intricata and Chondria dasyphylla. Algal biomass was 10.4 mol C m−2 during the present-day and 8.7 mol C m−2 and during the elevated pCO2 experiments. As previously observed, the increase in pCO2 resulted in a decrease in calcification from 0.041 ± 0.007 to 0.006 ± 0.003 mol CaCO3 m−2 d−1. Net community production (NCP) and dark respiration did not change in response to elevated pCO2. Light respiration measured by a new radiocarbon isotope dilution method exceeded dark respiration by a factor of 1.2 ± 0.3 to 2.1 ± 0.4 on a daily basis and by 2.2 ± 0.6 to 3.9 ± 0.8 on an hourly basis. The 1.8-fold increase with increasing pCO2 indicates that the enhanced respiration in the light was not due to photorespiration. Gross production (GPP) computed as the sum of NCP plus daily respiration (light + dark) increased significantly (0.24 ± 0.03 vs. 0.32 ± 0.04 mol C m−2 d−1). However, the conventional calculation of GPP based on the assumption that respiration in the light proceeds at the same rate as the dark underestimated the true rate of GPP by 41–100% and completely missed the increased rate of carbon cycling due to elevated pCO2. We conclude that under natural, undisturbed, nutrient-limited conditions elevated CO2 depresses calcification, stimulates the rate of turnover of organic carbon, particularly in the light, but has no effect on net organic production. The hypothesis that an increase pCO2 would produce an increase in net production that would counterbalance the effect of decreasing saturation state on calcification is not supported by these data.
Article
Full-text available
This study demonstrated that the increased partial pressure of CO 2 (pCO 2) in seawater and the attendant acidification that are projected to occur by the year 2300 will severely impact the early development of the oyster Crassostrea gigas. Eggs of the oyster were artificially fertilized and incubated for 48 h in seawater acidified to pH 7.4 by equilibrating it with CO 2-enriched air (CO 2 group), and the larval morphology and degree of shell mineralization were compared with the control treatment (air-equilibrated seawater). Only 5% of the CO 2 group developed into normal 'Dshaped' veliger larvae as compared with 68% in the control group, although no difference was observed between the groups up to the trochophore stage. Thus, during embryogenesis, the calcification process appears to be particularly affected by low pH and/or the low CaCO 3 saturation state of high-CO 2 seawater. Veliger larvae with fully mineralized shells accounted for 30% of the CO 2-group larvae, compared with 72% in the control (p < 0.005). Shell mineralization was completely inhibited in 45% of the CO 2-group larvae, but only in 16% of the control (p < 0.05). Normal D-shaped veligers of the control group exhibited increased shell length and height between 24 and 48 h after fertilization, while the few D-shaped veligers of the CO 2 group showed no shell growth during the same period. Our results suggest that future ocean acidification will have deleterious impacts on the early development of marine benthic calcifying organisms.
Article
Albert Roos and Walter F. Boron, “Intracellular pH,” vol. 61, no. 2, April 1981, p. 308: The constant R in Equations 14 and 16 should be M, M being defined as P HA /P A . The constant R' in Equations 15 and 17 should be N, N being defined as P B /P HB . The constant R in the definitions of α, β, ɣ, and δ is the gas constant. The expression [H ⁺ ] i + K in the denominator of the right-hand side of Equation 15 should be [H ⁺ ] o + K.
Article
Diazotrophic marine cyanobacteria in the genus Trichodesmium contribute a large fraction of the new nitrogen entering the oligotrophic oceans, but little is known about how they respond to shifts in global change variables such as carbon dioxide (CO2) and temperature. We compared Trichodesmium dinitrogen (N-2) and CO2 fixation rates during steady-state growth under past, current, and future CO2 scenarios, and at two relevant temperatures. At projected CO2 levels of year 2100 (76 Pa, 750 ppm), N-2 fixation rates of Pacific and Atlantic isolates increased 35-100%, and CO2 fixation rates increased 15-128% relative to present day CO2 conditions (39 Pa, 380 ppm). CO2- mediated rate increases were of similar relative magnitude in both phosphorus (P)-replete and P-limited cultures, suggesting that this effect may be independent of resource limitation. Neither isolate could grow at 15 Pa (150 ppm) CO2, but N-2 and CO2 fixation rates, growth rates, and nitrogen : phosophorus (N : P) ratios all increased significantly between 39 Pa and 152 Pa (1500 ppm). In contrast, these parameters were affected only minimally or not at all by a 4 degrees C temperature change. Photosynthesis versus irradiance parameters, however, responded to both CO2 and temperature but in different ways for each isolate. These results suggest that by the end of this century, elevated CO2 could substantially increase global Trichodesmium N-2 and CO2 fixation, fundamentally altering the current marine N and C cycles and potentially driving some oceanic regimes towards P limitation. CO2 limitation of Trichodesmium diazotrophy during past glacial periods could also have contributed to setting minimum atmospheric CO2 levels through downregulation of the biological pump. The relationship between marine N-2 fixation and atmospheric CO2 concentration appears to be more complex than previously realized and needs to be considered in the context of the rapidly changing oligotrophic oceans.
Chapter
Coral reefs are something we usually associate with warm, tropical waters and exotic fish, but not with the cold, deep and dark waters of the North Atlantic, where corals were regarded as oddities on the seafloor. It is now known that cold-water coral species also produce reefs which rival their tropical cousins in terms of their species richness and diversity. Increasing commercial operations in deep waters, and the use of advanced offshore technology have slowly revealed the true extent of Europe’s hidden coral ecosystems. This article reviews current knowledge about the reef-forming potential and the environmental controls of the scleractinian Lophelia pertusa along different deep-shelf and continental margin settings with special reference to NE Atlantic occurrences.
Article
Large areas of the inter-reefal seabed in the Great Barrier Reef are carpeted with vegetation composed almost entirely of the green calcareous alga Halineda. These meadows occur principally in the northern sections between 11°30′ and 15°35′S at depths of 20 to 40 m, but there are also some in the central and southern sections, where they have been found at depths down to 96 m. The vegetation is dominated by the same sprawling Halimeda species that are common on coral reefs in this region. However, on reefs these species grow on solid substrata, not soft sediments like the Halimeda-rich gravels that underlie the meadows. A total of 12 Halimeda species, together with two Udotea and one Penicillus species, are characteristic components of the shallow meadows. Below 50 m depth, species composition is restricted to only two major components. One, H. copiosa, is also important shallower, but the other is an unusually large and heavily calcified form of H. fragilis, a species that is normally a minor, fragile component of the shallow meadows. The maximum biomass found in these meadows was 4637 gm2 of calcareous algae, although the thean for vegetated areas was 525 gm2. These meadows are confined to the nutrient-depleted waters of the outer continental shelf just inside the outer barrier reefs, and are usually associated with distinct shoaling of the seabed caused by accumulation of thick deposits of calcareous Halimeda segments. The meadows are probably supported by very localized upwelling of nutrients from the adjacent Coral Sea onto the shelf, where they enrich the otherwise nutrient-depleted waters.
Article
Marine diatoms play a predominant role in the biological carbon pump¹ transferring carbon dioxide from surface to deep waters. Laboratory studies show that a number of species take up HCO3⁻ and concentrate inorganic carbon intracellularly allowing rapid growth despite low CO2 availability²,³. In contrast, many oceanographers, particularly when interpreting carbon isotope data⁴,⁵, have made the assumption that diatoms do not utilize the abundant HCO3⁻ in seawater but rather take up CO2 by diffusion⁶. This has led to the hypothesis that large diatoms may be CO2-limited in the oceans⁷. We now demonstrate active uptake of HCO3⁻ in the field and a carbon-concentrating mechanism in coastal Atlantic diatoms. By manipulating PCO2 we show that growth of large diatoms in the California upwelling is not limited by CO2 availability.
Article
The carbonate mineralogy of the calcified hydrozoan family Stylasteridae is controlled largely by phylogenetic rather than environmental factors. In a comprehensive study of the mineralogy of almost an entire family of calcareous organisms, this finding is well documented. Based on its mineralogy, a Tertiary calcitic stylasterid would probably belong to the Errinopsis-Errina-Errinopora species complex and have occurred in water less than 13°C; on the other hand, Tertiary aragonitic stylasterids were broadly distributed. The adaptive value of calcium carbonate polymorphs in Stylasteridae is still poorly understood. -from Authors
Article
In their Brevia “Scleractinian coral species survive and recover from decalcification” (30 March, p. [1811][1]), M. Fine and D. Tchernov present an exciting experimental approach documenting how coral skeletons dissolve as a physiological response to increased atmospheric CO2, a subject
Article
The present study has been done to make clear the effects of pH of culture water on the growth of the Japanese pearl oyster, Pinctada fucata (GOULD). Thirty five one-year-old oysters were equally divided into 7 groups, which were reared in separate recirculating tanks (Fig. 1) for 40 days. All the groups were given rice powder as food at a rate of 40mg per oyster per day, and 15l out of 40l of culture water in each tank was replaced with fresh sea-water once a day. The pH of water of the experimental tanks was first adjusted to 6 different levels from 7.3 to 8.1 by adding necessary amounts of hydrocloric acid or sodium borate to them and to keep the pH values constant calculated amounts of either chemical was added after every partial change of water, Chemical analysis of culture water and measurement of under-water weight of the animals were made seven times at five or seven-day intervals during the rearing period. The results obtained are summarized as follows: 1) Average pH values of culture water throughout the rearing period were 7.36, 7.48, 7.66, 7.78, 7.89 and 8.07 in the 6 experimental tanks and 8.04 in a control (Fig. 2). As to the alkalinity of culture water of the tanks was in the same order as pH (Fig. 4). No remarkable differences were observed on the other chemical conditions of culture water among the 7 tanks except for the two adjusted to pH 7.36 and 7.48 on the average (Figs. 5-7). 2) The oyster in pH 8.07 on the average and control tanks showed a rapid growth represented with respective straight lines throughout the rearing period (Fig. 10). Among the other oyster groups such a relation was found that decrease in oyster weight was in a direct proportion to pH. The greater part of the animals reared in pH 7.36 and 7.48 on the average died during the first half of rearing period (Figs. 10 and 11). The relation between the weekly mean value for pH and the daily increase of under-water weight of oysters differed with the stage of rearing (Fig. 14). The weight increases in a certain degree at higher pH, about 7.8 or over, and decreases remarkably at lower pH during the first 19 days. While after 20 days the relation is linear, being represented with the following expression. G(mg) 29.589 pH-234.794 Where G and pH show the weekly mean of daily increase of under-water weight and that of pH after 20 days. The limiting pH for growth is estimated from the expression to be pH 7.935. 3) From the significance test of the differences among the oyster groups in the dry weight of shell and that of meat at the end of rearing (Fig. 12), and the relationships between the appearance rate of etching and dissolving features on the surface of nacreous layer of the shell and the pH (Fig. 13), it may be concluded that the decrease in under-water weight of the oyst