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September 2007 - present
September 1996 - September 2007
April 1988 - September 1996
Publications
Publications (126)
Arrieta et al. (Reports, 17 April 2015, p. 331) propose that low concentrations of labile dissolved organic carbon (DOC) preclude prokaryotic consumption of a substantial fraction of DOC in the deep ocean and that this dilution acts as an alternative mechanism to recalcitrance for long-term DOC storage. Here, we show that the authors’ data do not s...
Despite its importance to ocean-climate interactions, the metabolic state of the oligotrophic ocean has remained controversial for >15 years. Positions in the debate are that it is either hetero- or autotrophic, which suggests either substantial unaccounted for organic matter inputs, or that all available photosynthesis (P) estimations (including (...
The magnitude of marine plankton net community production (NCP) is indicative of both the biologically driven exchange of carbon dioxide between the atmosphere and the surface ocean, and the export of organic carbon from the surface ocean to the oceaninterior. In this study the seasonal variability in the NCP of five biogeochemical regions in the N...
This paper reviews progress on understanding biological carbon sequestration in the ocean with special reference to the microbial formation and transformation of recalcitrant dissolved organic carbon (RDOC), the microbial carbon pump (MCP). We propose that RDOC is a concept with a wide continuum of recalcitrance. Most RDOC compounds maintain their...
Challenge 5: Unlock ocean-based solutions to climate change.
Enhance understanding of the ocean-climate nexus and generate knowledge and solutions to mitigate, adapt and build resilience to the effects of climate change across all geographies and at all scales, and to improve services including predictions for the ocean, climate and weather.
Kaartvedt et al. (2024; Mar Ecol Prog Ser 734:173–175) comment on the role internal waves played in the findings of Dewar-Fowler et al. (2023; Mar Ecol Prog Ser 715:27–39) that foray behaviour was present across a number of zooplankton species in the Polar Frontal Zone of the Southern Ocean. Kaartvedt et al. (2024) contend that foray behaviour may...
The ocean has been a regulator of climate change throughout the history of Earth. One key mechanism is the mediation of the carbon reservoir by refractory dissolved organic carbon (RDOC), which can either be stored in the water column for centuries or released back into the atmosphere as CO2 depending on the conditions. The RDOC is produced through...
In addition to diel vertical migration, individual zooplankton may also make a number of shorter-term migrations, or forays, into the surface layers from deeper depths. Direct observation of these forays is limited, particularly in the open ocean, which hinders our understanding of carbon flux via the biological carbon pump (BCP). We designed a nov...
The Challenger Society for Marine Science (CSMS) is the learned society for marine scientists based in the United Kingdom, with a membership of over 470 people from >100 institutions, across all academic career stages. Members of the CSMS have been interested in improving the representation of a diverse range of identities in UK marine science, lar...
Pursuing an academic career in marine science requires individuals to acquire a range of skills that can be applied across different contexts, including experimental or computational skills, policy engagement, teaching, and seagoing fieldwork. The tendency to advertise careers in marine science with imagery of research expeditions leads fieldwork t...
Diverse and inclusive marine research is paramount to addressing ocean sustainability challenges in the 21st century, as envisioned by the UN Decade of Ocean Science for Sustainable Development. Despite increasing efforts to diversify ocean science, women continue to face barriers at various stages of their career, which inhibits their progression...
The North Atlantic Ocean is the most intense marine sink for anthropogenic carbon dioxide (CO 2) in the world's oceans, showing high variability and substantial changes over recent decades. However, the contribution of biology to the variability and trend of this sink is poorly understood. Here we use in situ plankton measurements, alongside observ...
Ocean acidification poses a major threat to the structure and diversity of marine ecosystems. The marine seabed sustains important ecosystem functions, and so understanding the sensitivity to increased pCO2 within benthic invertebrates is critical for informing future management strategies. Here, we explore a traits-based approach for estimating th...
Interdisciplinary research is paramount to addressing ocean sustainability challenges in the 21st century. However, women leaders have been underrepresented in interdisciplinary marine research, and there is little guidance on how to achieve the conditions that will lead to an increased proportion of women scientists in positions of leadership. Her...
Temperate shelf seas are productive areas with the potential to export high quantities of particulate organic carbon (POC), as sinking particles, to the sediments or off‐shelf to the open ocean. The amount of carbon which can be exported depends partly on the amount of POC produced and on the remineralization processes occurring on the sinking mate...
The tropical Atlantic observing system was last reviewed in 2006 by CLIVAR (Climate and Ocean: Variability, Predictability and Change) and GCOS-GOOS-WCRP through the OOPC (Ocean Observations Panel for Climate), with a primary focus on PIRATA (Prediction and Research Moored Array in the Tropical Atlantic). Since then, the CLIVAR Tropical Atlantic Cl...
Microbial degradation of dissolved organic carbon (DOC) in aquatic environments can cause oxygen depletion, water acidification, and CO 2 emissions. These problems are caused by labile DOC (LDOC) and not refractory DOC (RDOC) that resists degradation and is thus a carbon sink. For nearly a century, chemical oxygen demand (COD) has been widely used...
Full report available from https://unesdoc.unesco.org/ark:/48223/pf0000376708.locale=en
doi:10.25607/h0gj-pq41
Disruptions to global science networks have followed COVID-19 restrictions. Rather than wait for a return to normal, we propose four areas that can ensure a productive and collaborative future for marine science.
Exploitation and degradation of the mysterious layer between the sunlit ocean surface and the abyss jeopardize fish stocks and the climate. Exploitation and degradation of the mysterious layer between the sunlit ocean surface and the abyss jeopardize fish stocks and the climate.
Diel vertical migration is a widespread behaviour amongst zooplankton, yet its effect on the rate at which individuals respire remains poorly understood. To address this, we investigated the effect of short-term temperature change on the respiration rate of Euphausia triacantha , a common component of the Southern Ocean zooplankton and a prominent...
The reduction of 2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride (INT) is increasingly being used as an indirect method to measure plankton respiration. Its greater sensitivity and shorter incubation time compared to the standard method of measuring the decrease in dissolved oxygen concentration, allows the determination of total...
This special issue presents some of the key findings from the pelagic component of the UK Shelf Sea Biogeochemistry Research Programme, carried out on the northwest European shelf between March 2014 and August 2015. The project aimed to address two issues: (1) how does a temperate shelf sea sustain an annual net drawdown and export of atmospheric C...
Global environmental changes are challenging the structure and functioning of ecosystems. However, a mechanistic understanding of how global environmental changes will affect ecosystems is still lacking. The complex and interacting biological and physical processes spanning vast temporal and spatial scales that constitute an ecosystem make this a f...
The tropical Atlantic is home to multiple coupled climate variations covering a wide range of timescales and impacting societally relevant phenomena such as continental rainfall, Atlantic hurricane activity, oceanic biological productivity, and atmospheric circulation in the equatorial Pacific. The tropical Atlantic also connects the southern and n...
Zooplankton fecal pellets (FPs) are important conduits of carbon from the surface to the deep ocean, as shown by their presence in deep-sea sediment traps. Zooplankton themselves are thought to play an important role in the breakdown and reworking of FPs as they sink, whilst processes such as diel vertical migration (DVM) may enhance the supply of...
Knowledge of the magnitude and variability of plankton respiration is a crucial gap in our understanding of marine carbon cycling. In order to validate the INT reduction method as a proxy for plankton respiration, we have compiled and analyzed a dataset (n = 376) of concurrent measurements of dissolved oxygen consumption (CRO2) and in vivo reductio...
Microbial plankton respiration is the key determinant in the balance between the storage of organic carbon in the oceans or its conversion to carbon dioxide with accompanying consumption of dissolved oxygen. Over the past 50 years, dissolved oxygen concentrations have decreased in many parts of the world’s oceans, and this trend of ocean deoxygenat...
Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g., CO2, CaCO3, organic matter) in the ocean are complex...
The seasonal variability of plankton metabolism indicates how much carbon is cycling within a system, as well as its capacity to store carbon or export organic matter and CO2 to the deep ocean. Seasonal variability between November 2014, April 2015 and July 2015 in plankton respiration and bacterial (Bacteria + Archaea) metabolism is reported for t...
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about mi...
Spring phytoplankton blooms are important events in Shelf Sea pelagic systems as the increase in carbon production results in increased food availability for higher trophic levels and the export of carbon to deeper waters and the sea-floor. It is usually accepted that the increase in phytoplankton abundance and production is followed by an increase...
The process of ocean acidification is now relatively well-documented
at the global scale as a long-term trend in the open ocean. However,
short-term and spatial variability can be high.
New datasets made available since Charting Progress 2 make it
possible to greatly improve the characterisation of CO2 and ocean
acidification in UK waters.
Nature Communications 6:6961 doi: 10.1038/ncomms7961 (2015); Published April242015; Updated 2016
The original version of this Article failed to fully credit the use of the Ocean Data View software in figure 3, which appears below:
Schlitzer, R., Ocean Data View, http://odv.awi.de, 2016.
The Integrated Marine Biogeochemistry and Ecosystem Research (IMBER) project aims at developing a comprehensive understanding of and accurate predictive capacity of ocean responses to accelerating global change and the consequent effects on the Earth system and human society. Understanding the changing ecology and biogeochemistry of marine ecosyste...
Instrumental equipment unsuitable or unavailable for fieldwork as well as
lack of ship space can necessitate the preservation of seawater samples
prior to analysis in a shore-based laboratory. Mercuric chloride
(HgCl2) is routinely used for such preservation, but its handling and
subsequent disposal incur environmental risks and significant expense...
The AMT (www.amt-uk.org) is a multidisciplinary programme which undertakes biological, chemical, and physical oceanographic research during an annual voyage between the UK and a destination in the South Atlantic such as the Falkland Islands, South Africa, or Chile. This transect of >12,000 km crosses a range of ecosystems from subpolar to tropical,...
Instrumental equipment unsuitable or unavailable for fieldwork as well as lack of ship space can necessitate the preservation of seawater samples prior to analysis in a shore-based laboratory. Mercuric chloride (HgCl2) is routinely used for such preservation, but its handling and subsequent disposal incur significant risks and expense. Benzalkonium...
This paper reviews progress on understanding biological carbon
sequestration in the ocean with special reference to the microbial
formation and transformation of recalcitrant dissolved organic
carbon (RDOC), the microbial carbon pump (MCP). We propose that RDOC
is a relative concept with a wide continuum of recalcitrance. Most
RDOC compounds mainta...
IMBER Open Science Conference (OSC) 2014.
"Future Oceans - Research for marine sustainability multiple stressors, drivers, challenges & soutions" - 23-27 June 2014, Bergen, Norway
Complete booklet, with programme, abstrats, participants & sponsors. 621 p.
[IMBER OSC 2014 Scientific Organising Committee: Eileen Hofmann (Chair, USA), Ratana Chuenpagd...
We carried out 16 photochemical experiments of filtered surface water in a custom-built solar simulator and concomitant measurements of in vitro gross primary production (GPP) and respiration (R) in the Mauritanian upwelling during a Lagrangian study following three sulfur hexafluoride–labeled patches of upwelled water (P1 to P3). Oxygen photolysis...
A laboratory study was undertaken to determine the effect of food
quality on feeding, respiration, reproduction and the resulting carbon
budget of Temora longicornis. The stoichiometric ratios N : P, C : N and
C : P of Rhodomonas salina were used as indicators of food quality. R.
salina was grown in media with different inorganic nutrient
concentra...
Fifty years ago, there was ‘A discussion on progress and needs of marine science’ at the Royal Society [1]. George Deacon wrote in the Introduction (p. 286): ‘A hundred years ago the Society often listened to papers about the ocean, but the rapid growth of science … has led to some neglect of large-scale natural processes’. Today, marine science is...
Within the context of UK marine science, we project a strategy for ocean circulation research over the next 20 years. We recommend a focus on three types of research: (i) sustained observations of the varying and evolving ocean circulation, (ii) careful analysis and interpretation of the observed climate changes for comparison with climate model pr...
The Mauritanian upwelling system is one of the most biologically productive regions
of the world’s oceans. Coastal upwelling transfers nutrients to the sun-lit surface ocean,
thereby stimulating phytoplankton growth. Upwelling of deep waters also supplies
dissolved inorganic carbon (DIC), high levels of which lead to low calcium carbonate
saturatio...
Metabolic activity in the water column below the euphotic zone is ultimately fuelled by the vertical flux of organic material from the surface. Over time, the deep ocean is presumably at steady state, with sources and sinks balanced. But recently compiled global budgets and intensive local field studies suggest that estimates of metabolic activity...
The mesopelagic zone is the oceanic region through which carbon and other elements must pass in order to reach deeper waters or the sea floor. However, the food web interactions that occur in the mesopelagic zone are difficult to measure and so, despite their crucial importance to global elemental cycles, are not very well known. Recent development...
We present, test and implement two contrasting models to predict euphotic zone net community production (NCP), which are based on 14C primary production (PO14CP) to NCP relationships over two latitudinal (ca. 30°S–45°N) transects traversing highly productive and oligotrophic provinces of the Atlantic Ocean (NADR, CNRY, BENG, NAST-E, ETRA and SATL,...
Euphotic zone plankton production (P) and respiration (R) were determined from the in vitro flux of dissolved oxygen during six latitudinal transects of the Atlantic Ocean, as part of the Atlantic Meridional Transect (AMT) programme. The transects traversed the North and South Atlantic Subtropical Gyres (N gyre, 18–38°N; S gyre, 11–35°S) in April–J...
The aims of the Atlantic Meridional Transect (AMT) Programme [www.amt-uk.org] are to quantify the nature and causes of ecological and biogeochemical variability in the planktonic ecosystems of the Atlantic Ocean, and to assess the effects of this variability on biological carbon cycling and air–sea exchange of radiatively active gases and aerosols...
We discuss nitrous oxide (N2O) and methane (CH4) distributions in 49 vertical profiles covering the upper ∼300 m of the water column along two ∼13,500 km transects between ∼50°N and ∼52°S during the Atlantic Meridional Transect (AMT) programme (AMT cruises 12 and 13). Vertical N2O profiles were amenable to analysis on the basis of common features c...
ABSTRACT: Plankton production was measured using 8 techniques at 4 stations in the Celtic Sea, North Atlantic Ocean, in April 2002. Primary production (PP) was derived from 14C incorporation into particulate carbon after 24 h simulated in situ, PP(14CSIS), and 2 h photosynthesis-irradiance incubations, PP(14CPUR), and from 2 published satellite alg...
Introduction Measurement of Bacterial Respiration and Production Magnitude and Variability of Bacterial Respiration Relationship Between Bacterial Respiration and Environmental and Ecological Factors Bacterial Respiration as a Proportion of Community Respiration Predicting Bacterial Respiration Comparison Between Measurements and Predictions of Bac...
Our understanding of the role of marine phytoplankton
in the global biogeochemical cycles of carbon and
sulphur, particularly the rates and variability of primary
production and calcification, phytoplankton activity and
ecology in the subsurface chlorophyll maximum, and
the use of satellite remote sensing to detect coccolithophore
blooms, has progr...
We used data collected at >60 stations over a 10 yr period to build the carbon budget of
the plankton community in the euphotic layer of the Eastern North Atlantic Subtropical Gyre (NASE).
Autotrophic biomass exceeded microbial heterotrophic biomass by a factor of 1.7. Mean (±SE), integrated
chlorophyll a concentration and net particulate primary p...
The anthropogenic CO2 accumulation rate for the North Atlantic Ocean was estimated on the basis of the decrease in the delta 13C of the dissolved inorganic carbon measured between cruises in 1981 (Transient Tracers in the North Atlantic), 1993 (OACES) and 2003 (Repeat Hydrography). A mean depth-integrated delta 13C change of -15.0 +/- 3.80/00 m yr-...
The aims of the Atlantic Meridional Transect (AMT) programme [www.amt-uk.org] are to quantify the nature and
causes of ecological and biogeochemical variability in the planktonic ecosystems of the Atlantic Ocean, and to assess the effects of this variability on biological carbon cycling and air–sea exchange of radiatively active gases and aerosols....
Recent experimental data from the subtropical NE Atlantic appear to support the prevalence of net heterotrophy in unproductive pelagic ecosystems. However, the proximity of these studies to the NW African upwelling does not exclude the possibility that remote areas of the oceanic gyres are in metabolic balance. Here we present measurements of plank...
The Atlantic Meridional Transect (AMT) Programme (1995-2006) [http://www.pml.ac.uk/amt/index.html] aims to quantify the nature and causes of ecological and biogeochemical variability in the planktonic ecosystems of the tropical and temperate Atlantic Ocean, and the effects of this variability on biological carbon cycling and air-sea exchange of rad...
Sunlight-initiated photolysis of chromophoric dissolved organic matter (CDOM) is the dominant source of carbon monoxide (CO) in the open-ocean. A modelling study was conducted to constrain this source. Spectral solar irradiance was obtained from two models (GCSOLAR and SMARTS2). Water-column CDOM and total light absorption were modelled using spect...
We measured prokaryotic production and respiration in the major water masses of the North Atlantic down to a depth of ~4,000 m by following the progression of the two branches of North Atlantic Deep Water (NADW) in the oceanic conveyor belt. Prokaryotic abundance decreased exponentially with depth from $3 to 0.4 \times 10^5 cells mL^{-1}$ in the ea...
Understanding how climate change will affect the planet is a key issue worldwide. Questions concerning the pace and impacts of climate change are thus central to many ecological and biogeochemical studies, and addressing the consequences of climate change is now high on the list of priorities for funding agencies. Here, we review the interactions b...
Oithona spp. is considered the most abundant and ubiquitous copepod genus in the
marine environment, often outnumbering calanoid copepods throughout the year. Previous studies
have argued that one of the reasons for such success is that the respiration rate of Oithona spp. is
insensitive to temperature changes and lower than in calanoids. However,...
This chapter reviews the current state of knowledge of the process and measurement of microplankton
respiration in marine surface waters. The principal approaches are outlined and their potentials and limitations
discussed. A global database, containing 1662 observations has been compiled and analyzed for
the spatial and temporal distribution of su...
This paper presents an overview of dimethyl sulphide biogeochemistry within a coccolithophore bloom (DISCO), an integrated, multidisciplinary Lagrangian process study of the routes, rates and controls on the biogeochemical cycling of dimethyl sulphide (DMS) within a growing bloom of the coccolithophorid alga, Emiliania huxleyi. The Lagrangian study...
Plankton dark community respiration (DCR), gross production (GP), bacterial production, protozoan herbivory, and phytoplankton, microzooplankton and heterotrophic bacterial abundance were measured during a bloom of the coccolithophore Emiliania huxleyi. The study, which was conducted in the northern North Sea during June 1999, included a spatial su...
Phytoplankton biomass and rates of nitrogen and carbon uptake were determined during a six-day Lagrangian experiment in the northern North Sea (58°56′N 02°52′E–58°20′N 03°28′E) in June 1999. Satellite remotely sensed images and shipboard observations were used to select an initial position within a bloom of Emiliania huxleyi. The euphotic zone was...
In vitro measurements, predictions, and geochemical estimates of the balance between gross primary production (GPP) and community respiration (CR) in the open ocean do not agree. This has generated an active debate about the carbon balance in unproductive pelagic marine ecosystems. The analysis of generalized GPP:CR relationships that sustains this...
Concurrent measurements of dark community respiration (DCR), gross production (GP), size fractionated primary production (14C PP), nitrogen uptake, nutrients, chlorophyll a concentration, and heterotrophic and autotrophic bacterial abundance were collected from the upper 200 m of a latitudinal (32°S–48°N) transect in the Eastern Atlantic Ocean duri...
A knowledge of the balance between plankton gross primary production (GPP) and community respiration (CR) in the open ocean is vital to the accurate determination of the global carbon cycle, yet the paucity of open ocean measurements severely limits our understanding. This study measured GPP, net community production, dark CR, and size-fractionated...
The aims of the Aegean Hydrothermal Fluxes and Biological Production project were to estimate the fluxes of fluids, chemicals, heat and bacteria from hydrothermal vents, establish the controls on venting dynamics, measure the productivity in the region of the vents and establish the effect of the vents on biodiversity of both prokaryotes and eukary...
Plankton gross production, net community production and dark community respiration were measured at coastal sites around the island of Milos, Aegean Sea, during June and September 1996 and June 1997. Sampling sites were chosen to include those with and without visible signs of hydrothermal activity. Plankton gross production ranged from undetectabl...