Tyler Cyronak

Georgia Southern University | GSU

Accurate measurements of seawater carbonate chemistry are crucial for marine carbon cycle research. Certified reference materials (CRMs) are typically analyzed alongside samples to correct measurements for calibration drift. However, the COVID‐19 pandemic led to a limited access to CRMs. In response to this shortage, we prepared and monitored in‐ho...

This chapter focuses on considerations for conducting open-system field experiments in the context of ocean alkalinity enhancement (OAE) research. By conducting experiments in real-world marine systems, researchers can gain valuable insights into ecological dynamics, biogeochemical cycles, and the safety, efficacy, and scalability of OAE techniques...

Ocean deoxygenation is predicted to threaten marine ecosystems globally. However, current and future oxygen concentrations and the occurrence of hypoxic events on coral reefs remain underexplored. Here, using autonomous sensor data to explore oxygen variability and hypoxia exposure at 32 representative reef sites, we reveal that hypoxia is already...

The California Current System experiences seasonal ocean acidification and hypoxia (OAH) owing to wind-driven upwelling, but little is known about the intensity, frequency, and depth distribution of OAH in the shallow nearshore environment. Here we present observations of OAH and dissolved inorganic carbon and nutrient parameters based on monthly t...

The Earth’s climate is strongly affected by the partitioning of carbon between its mobile reservoirs, primarily between the atmosphere and the ocean. The distribution between the reservoirs is being massively perturbed by human activities, primarily due to fossil fuel emissions, with a range of consequences, including ocean warming and acidificatio...

Ocean alkalinity enhancement (OAE) is a method that can remove carbon dioxide (CO2) from the atmosphere and counteract ocean acidification through the dissolution of alkaline minerals. Currently, critical knowledge gaps exist regarding the dissolution of different minerals suitable for OAE in natural seawater. Of particular importance is to underst...

Benthic incubation chambers facilitate in-situ metabolism studies in shallow water environments. They are used to isolate the water surrounding a study organism or community so that changes in water chemistry can be quantified to characterise physiological processes such as photosynthesis, respiration, and calcification. Such field measurements cap...

The role of phytoplankton as ocean primary producers and their influence on global biogeochemical cycles makes them arguably the most important living organisms in the sea. Like plants on land, phytoplankton exhibit seasonal cycles that are controlled by physical, chemical, and biological processes. Nearshore coastal waters often contain the highes...

Coastal populations and hazards are escalating simultaneously, leading to an increased importance of coastal ocean observations. Many well-established observational techniques are expensive, require complex technical training, and offer little to no public engagement. Smartfin, an oceanographic sensor–equipped surfboard fin and citizen science prog...

Nearshore coastal waters are highly dynamic in both space and time. They can be difficult to sample using conventional methods due to their shallow depth, tidal variability, and the presence of breaking waves. High resolution satellite sensors can be used to provide synoptic views of Surface Temperature (ST), but the performance of such ST products...

Coral reef metabolism underpins ecosystem function and is defined by the processes of photosynthesis, respiration, calcification, and calcium carbonate dissolution. However, the relationships between these physiological processes at the organismal level and their interactions with light remain unclear. We examined metabolic rates across a range of...

Salinity normalization of total alkalinity (TA) and dissolved inorganic carbon (DIC) data is commonly used to account for conservative mixing processes when inferring net metabolic modification of seawater by coral reefs. Salinity (S), TA, and DIC can be accurately and precisely measured, but salinity normalization of TA (nTA) and DIC (nDIC) can ge...

Ocean Alkalinity Enhancement (OAE) has been proposed as a method to remove carbon dioxide (CO2) from the atmosphere and to counteract ocean acidification. It involves the dissolution of alkaline minerals such as quick lime, CaO, and hydrated lime, Ca(OH)2. However, a critical knowledge gap exists regarding their dissolution in natural seawater. Par...

Accurately predicting the effects of ocean and coastal acidification on marine ecosystems requires understanding how responses scale from laboratory experiments to the natural world. Using benthic calcifying macroalgae as a model system, we performed a semi-quantitative synthesis to compare directional responses between laboratory experiments and f...

Globally, coral reefs are threatened by ocean warming and acidification. The degree to which acidification will impact reefs is dependent on the local hydrodynamics, benthic community composition, and biogeochemical processes, all of which vary on different temporal and spatial scales. Characterizing the natural spatiotemporal variability of seawat...

Plain Language Summary The oceans absorb carbon dioxide from the atmosphere but can emit the more potent greenhouse gases of methane and nitrous oxide. Large uncertainties remain in oceanic greenhouse gas budgets due to variation in regional emissions from environmental factors such as upwelling, oxygen depletion, continental nutrient inputs and se...

Plain Language Summary Positive rates of net ecosystem calcification and net ecosystem production are regarded as fundamental to the healthy functioning of coral reef ecosystems. In particular, positive ecosystem calcification is required to maintain the structural complexity that sustains many of the ecosystem functions of coral reefs. While most...

Global and local anthropogenic stressors such as climate change, acidification, overfishing, and pollution are expected to shift the benthic community composition of coral reefs from dominance by calcifying organisms to dominance by non‐calcifying algae. These changes could reduce the ability of coral reef ecosystems to maintain positive net calciu...

The accuracy and precision of satellite sea surface temperature (SST) products in nearshore coastal waters are not well known, owing to a lack of in-situ data available for validation. It has been suggested that recreational watersports enthusiasts, who immerse themselves in nearshore coastal waters, be used as a platform to improve sampling and fi...

Ion‐sensitive field effect transistor‐based pH sensors have been shown to perform well in high frequency and long‐term ocean sampling regimes. The Honeywell Durafet is widely used due to its stability, fast response, and characterization over a large range of oceanic conditions. However, potentiometric pH monitoring is inherently complicated by the...

Seagrass systems are integral components of both local and global carbon cycles and can substantially modify seawater biogeochemistry, which has ecological ramifications. However, the influence of seagrass on porewater biogeochemistry has not been fully described, and the exact role of this marine macrophyte and associated microbial communities in...

Due to decreases in seawater pH resulting from ocean acidification, permeable calcium carbonate reef sands are predicted to be net dissolving by 2050. However, the rate of dissolution and factors that control this rate remain poorly understood. Experiments performed in benthic chambers predict that reefs will become net dissolving when the aragonit...

Nearshore coastal waters are among the most dynamic regions on the planet and difficult to sample from conventional oceanographic platforms. It has been suggested that environmental sampling of the nearshore could be improved by mobilising vast numbers of citizens who partake in marine recreational sports, like surfing. In this paper, we compared t...

Coral reefs are facing intensifying stressors, largely due to global increases in seawater temperature and decreases in pH. However, there is extensive environmental variability within coral reef ecosystems, which can impact how organisms respond to global trends. We deployed spatial arrays of autonomous sensors across distinct shallow coral reef h...

Shallow, permeable calcium carbonate (CaCO3) sediments make up a large proportion of the benthic cover on coral reefs and account for a large fraction of the standing stock of CaCO3. There have been a number of laboratory, mesocosm, and in situ studies examining shallow sediment metabolism and dissolution, but none of these have considered seasonal...

Climate change refugia in the terrestrial biosphere are areas where species are protected from global environmental change and arise from natural heterogeneity in landscapes and climate. Within the marine realm, ocean acidification, or the global decline in seawater pH, remains a pervasive threat to organisms and ecosystems. Natural variability in...

There is a growing recognition for the need to understand how seawater carbonate chemistry over coral reef environments will change in a high-CO2 world to better assess the impacts of ocean acidification on these valuable ecosystems. Coral reefs modify overlying water column chemistry through biogeochemical processes such as net community organic c...

We investigated coral reef carbonate chemistry dynamics and metabolic rates using an automated system that measured total alkalinity (TA, 30 min intervals), pH on the total scale (pHT, 10 min intervals) and the partial pressure of carbon dioxide (pCO2, 1 min intervals) over 2 weeks at Heron Island (Great Barrier Reef, Australia). The calculation of...

Acid reef-flux The uptake of anthropogenic carbon dioxide from the atmosphere is reducing the pH of the oceans. Ocean acidification means that calcium carbonate—the material with which coral reefs are built—will be more difficult for organisms to generate and will dissolve more quickly. Eyre et al. report that some reefs are already experiencing ne...

Worldwide, coral reef ecosystems are experiencing increasing pressure from a variety of anthropogenic perturbations including ocean warming and acidification, increased sedimen-tation, eutrophication, and overfishing, which could shift reefs to a condition of net calcium carbonate (CaCO 3) dissolution and erosion. Herein, we determine the net calci...

Regression of average ΔTA using non-normalized and salinity normalized TA data. For ΔnTA data were normalized to the average salinity of each reef site. (TIF)

Data from the global TA-DIC coral reef analysis. Columns are (1) location of each study; (2) ocean basin the study was conducted in; (3) slope of the TA-DIC vector; (4) percent influence of NCP on changes in DIC; (5) R2 of the TA-DIC slope; (6) slopes of TA-DIC vectors normalized to the average salinity at each site (nTA-nDIC); (7) mean TA anomaly...

The percent occurrence of net dissolution (red squares) and the average depletion of TA relative to offshore (ΔTA; blue circles) versus the TA-DIC slope from each dataset. (TIF)

Map of the coral reef sites used in this study. Some locations were combined because there was not enough spatial resolution to show as two distinct points. The colors and symbols indicate whether the reefs are in the Atlantic (green circles), Great Barrier Reef (red squares), Indo-Pacific (blue triangles), and other (grey diamonds) regions. (TIF)

Regression of non-normalized and salinity normalized TA-DIC slopes. To calculate the salinity normalized slope (nTA-nDIC), TA and DIC data were normalized to the average salinity of each site. (TIF)

It has been hypothesized that highly productive coastal ecosystems, such as seagrass meadows, could lead to the establishment of ocean acidification (OA) refugia, or areas of elevated pH and aragonite saturation state (Ωa) compared to source seawater. However, seagrass ecosystems experience extreme variability in carbonate chemistry across short te...

Estuaries are important subcomponents of the coastal ocean, but knowledge about the temporal and spatial variability of their carbonate chemistry, as well as their contribution to coastal and global carbon fluxes, are limited. In the present study, we measured the temporal and spatial variability of biogeochemical parameters in a saltmarsh estuary...

Accurate observations of the Earth system are required to understand how our planet is changing and to help manage its resources. The aquatic environment—including lakes, rivers, wetlands, estuaries, coastal and open oceans—is a fundamental component of the Earth system controlling key physical, biological, and chemical processes that allow life to...

A novel chemical sensor package named “WavepHOx” was developed in order to facilitate measurement of surface ocean pH, dissolved oxygen, and temperature from mobile platforms. The system comprises a Honeywell Durafet pH sensor, Aanderaa optode oxygen sensor, and chloride ion selective electrode, packaged into a hydrodynamic, lightweight housing. Th...

Increasing atmospheric CO 2 is raising sea surface temperature (SST) and increasing seawater CO 2 concentrations, resulting in a lower oceanic pH (ocean acidification; OA), which is expected to reduce the accretion of coral reef ecosystems. Although sediments comprise most of the calcium carbonate (CaCO 3) within coral reefs, no in situ studies hav...

Coral reef net ecosystem calcification (NEC) has decreased for many Caribbean reefs over recent decades primarily due to a combination of declining coral cover and changing benthic community composition. Chemistry-based approaches to calculate NEC utilize the drawdown of seawater total alkalinity (TA) combined with residence time to calculate an in...

The literature on ocean acidification (OA) contains a prevalent misconception that reduced organismal calcification rates in an acidifying ocean are drivenbya reduction in carbonate ion (CO3²⁻) substrate availability (e.g. Omega or Ω). However, recent researchin diverse organisms suggests that a reduction in seawater pH (i.e. increasing proton conc...

Currently, almost any article searched with the keywords “calcification” and “ocean acidification” (OA) will inevitably bring up a link between calcification and bulk seawater carbonate saturation state (Ω) as a justification for the study. Therefore, it seems timely to highlight that from a physiological point of view, there are mechanisms that in...

Various life cycle stages of cyst-producing dinoflagellates often appear differently colored under the microscope; gametes appear paler while zygotes are darker in comparison to vegetative cells. To compare physiological and photochemical competency, the pigment composition of discrete life cycle stages was determined for the common resting cyst-pr...

The drivers of coastal water pH are far more complex than the open ocean and include the delivery of nutrients, acids, inorganic and organic carbon and alkalinity from the catchment, ecosystem metabolism and benthic biogeochemical processes. These factors that control the pH of coastal waters operate on a range of spatial (local to global) and temp...

Predictions of future impact of climate change on coral reefs indicate that bleaching mortality due to higher temperature will be the major factor in the decline of coral reefs. Ocean acidification (OA) is increasingly considered to be an important contributing factor, but estimates of its importance vary widely in the literature. Models of future...

Automated cavity ring down spectroscopy was used to make continuous measurements of dissolved methane, nitrous oxide and carbon dioxide in a coral reef lagoon for two weeks (Heron Island, Great Barrier Reef). Radon (222Rn) was used to trace the influence of tidally-driven porewater exchange on greenhouse gas dynamics. Clear tidal variation was obse...

The carbon isotopic signature (δ13C) of coral skeletons is influenced by isotopic fractionation (εorg) during photosynthetic dissolved inorganic carbon (DIC) fixation, but only a few direct εorg measurements are available in coral communities. In particular, observations of εorg at the ecosystem scale are lacking. Here we present high frequency (ho...

Annual Emiliania huxleyi blooms (along with other coccolithophorid species) play important roles in the global carbon and sulfur cycles. E. huxleyi blooms are routinely terminated by large, host-specific dsDNA viruses, (Emiliania huxleyi Viruses; EhVs), making these host-virus interactions a driving force behind their potential impact on global bio...

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Physical uptake of anthropogenic CO2 is the dominant driver of ocean acidification (OA) in the open ocean. Due to expected decreases in calcification and increased dissolution of CaCO3 framework, coral reefs are thought to be highly susceptible to OA. However, biogeochemical processes can influence the pCO2 and pH of coastal ecosystems on diel and...

Marine phytoplankton play critical roles in the biogeochemistry of open and coastal oceans. However, the impact that individual species have on an ecosystem-wide scale can strongly depend on the production of cellular compounds, especially those that are climatically active such as dimethylsulfide (DMS). Herein, we use sorting flow cytometry to sep...

The impact of groundwater on pCO2 variability was assessed in two coral reef lagoons with distinct drivers of submarine groundwater discharge (SGD). Diel variability of pCO2 in the two ecosystems was explained by a combination of biological drivers and SGD inputs. In Rarotonga, a South Pacific volcanic island, SGD was driven primarily by a steep te...

Some predictions of how ocean acidification (OA) will affect coral reefs assume a linear functional relationship between the ambient seawater aragonite saturation state (Omega a) and net ecosystem calcification (NEC). We quantified NEC in a healthy coral reef lagoon in the Great Barrier Reef during different times of the day. Our observations revea...

1] Some predictions of how ocean acidification (OA) will affect coral reefs assume a linear functional relationship between the ambient seawater aragonite saturation state (Ω a) and net ecosystem calcification (NEC). We quantified NEC in a healthy coral reef lagoon in the Great Barrier Reef during different times of the day. Our observations reveal...

[1] Ocean acidification (OA) is expected to drive the transition of coral reef ecosystems from net calcium carbonate (CaCO3) precipitating to net dissolving within the next century. Although permeable sediments represent the largest reservoir of CaCO3 in coral reefs, the dissolution of shallow CaCO3 sands under future pCO2 levels has not been measu...

To better predict how ocean acidification will affect coral reefs, it is important to understand how biogeochemical cycles on reefs alter carbonate chemistry over various temporal and spatial scales. This study quantifies the contribution of shallow porewater exchange (as quantified from advective chamber incubations) and fresh groundwater discharg...

Atmospheric radon (222Rn) and carbon dioxide (CO2) concentrations were used to gain insight into fugitive emissions in an Australian coal seam gas (CSG) field (Surat Basin, Tara region, Queensland). 222Rn and CO2 concentrations were observed for 24 h within and outside the gas field. Both 222Rn and CO2 concentrations followed a diurnal cycle with n...

Dissolved inorganic carbon, dissolved oxygen, H+, and alkalinity fluxes from permeable carbonate sediments at Heron Island (Great Barrier Reef) were measured over one diel cycle using benthic chambers designed to induce advective pore-water exchange. A complex hysteretic pattern between carbonate precipitation and dissolution in sands and the arago...

Ocean acidification (OA) is expected to drive the transition of coral reef ecosystems from net calcium carbonate (CaCO3) precipitating to net dissolving within the next century. Although permeable sediments represent the largest reservoir of CaCO3 in coral reefs, the dissolution of shallow CaCO3 sands under future pCO2 levels has not been measured...

To better predict how ocean acidification will affect coral reefs, it is important to understand how biogeochemical cycles on reefs alter carbonate chemistry over various temporal and spatial scales. This study quantifies the contribution of fresh groundwater discharge (as traced by radon) and shallow porewater exchange (as quantified from advectiv...