Archive Page 46

New edition of the OA-ICC highlights: June – December 2024

Published 20 March 2025 Newsletters and reports Closed

The OA-ICC has released a new edition of the OA-ICC Highlights, which covers main activities and events taken up by the project from June to December of 2024. Updates in this issue include:

  • Launch of New Technical Cooperation Project with Ocean Acidification Component
  • Annual OA-ICC Expert Group Meeting
  • Basic Training Workshopon Ocean Acidification
  • Annual Meeting of the SCOR project Changing Ocean Biological Systems
  • International Workshop on the Socio-Economic Impacts of Multiple Stressors
  • IAEA and Prince Albert II of Monaco Foundation Strengthen Long-Term Partnership on Ocean Acidification
  • Ocean Acidification Capacity Development Workshop
  • 2nd Winter School on Ocean Acidification and Multiple Stressors
  • 4th edition of OA Week
  • OA-ICC at COP29

Previous editions of the “OA-ICC Highlights” can be viewed here.

OA-ICC, 20 March 2025. Newsletter.

Decadal progress of ocean acidification over the Southern Ocean

Published 19 March 2025 Science Closed
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The Southern Ocean (SO, south of 30°S) covers 30% of the global ocean surface area and is presumed to account for 40% of the whole ocean’s anthropogenic CO 2 (DICanth) absorption1. This may lead to intensive anthropogenic acidification in the SO. However, natural processes also influence the change of ocean pH. Distinguishing anthropogenic and natural components from the observed dissolved inorganic carbon (DIC) and pH is essential for clarifying the acidification in the SO. Here we separated the anthropogenic and natural components by combining new parameterization techniques with high-resolution grid data constructed based on ship-based observations. During the 1990s‒2010s, ocean acidification affected by the anthropogenic effect covered most of the surface and intermediate depths by 3500 m over the SO, and the maximum decreasing rate of anthropogenic pH was 0.004 pH year–1 as twice decreasing of the global average. This remarkable decline of pH in the SO must result from the increase in DICanth of 10.9 Pg-C. The increase of DICanth in the SO was comparable to 11% of the global emission amount of CO2, implying the SO absorbing half of the global ocean’s DICanth is the largest uptake region of atmospheric anthropogenic carbon into the ocean interior.

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Scientists at AOML monitor the impacts of ocean acidification on reefs with new series of buoys 

Published 18 March 2025 Web sites and blogs Closed

Scientists at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) and the Cooperative Institute for Marine and Atmospheric Sciences (CIMAS) deployed a new series of Sofar “Spotter” buoys at four of the seven Mission: Iconic Reefs within the Florida Keys National Marine Sanctuary (FKNMS) identified as essential sites for restoration.

The Sofar buoy at the surface measures wave energy, wind speed, sea surface temperature, and pressure. Below the surface, integrated sensors measure pH and seafloor temperature in near-real time – actively monitoring ocean acidification on crucial reefs. 

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The global impacts of ocean acidification are well-known. But a decade-long study led by scientists at AOML revealed last year that there are spatial gradients in how OA progresses across the Florida Keys, and some sites in the Upper Keys may act as refugia able to mitigate a decrease in pH – potentially due to the higher abundance of seagrass beds and other benthic communities. 

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With these Sofar buoys and a newly-developed online application, scientists with AOML’s Coral Program are now actively seeing how conditions fluctuate and monitoring instrument functionality in real-time at four of the seven Mission: Iconic Reefs: Carysfort, Horseshoe, Cheeca Rocks and Sombrero Reefs in real-time.

However, the true advantage that set the Sofar “Spotter” buoy for the team came with their ability to customly integrate an advanced sensor monitoring changes in pH across these reefs.

While probes and pH electrodes, are often strapped to buoys and other deployable instrumentation in the marine environment. These sensors may not be of sufficient quality to monitor the gradual progression of OA and over time they degrade, leading to drifting data that can compromise a monitoring program Scientists with AOML’s Coral Program have taken a different approach. 

The Sofar Spotter buoy floats at the surface monitoring ocean conditions with a protected data cable running to the seabed. The bristlemouth development kit  (center) receives  pH and temperature data from the SAMI-pH sensor (bottom left). 

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Postdoc position – co-construction and evaluation of prospective scenarios for marine carbon dioxide removal

Published 17 March 2025 Jobs Closed

IRD (French National Research Institute for Sustainable Development), UMR LEMAR
Contract duration: 24 months
Location: Brest, France

The organization and project you are joining
Your position will be funded by the TRACCOS project of the Ocean & Climate Priority research program (PPR Océan & Climat1). TRACCOS focuses on the transdisciplinary assessment of governance issues associated with the deployment of marine carbon dioxide removal (mCDR) techniques at the international level. The project aims to understand the issues associated with funding, the techniques envisaged for Monitoring, Reporting and Verification (MRV), societal acceptability, and the governance framework for deploying mCDR strategies.. The results of this project will thus help to inform policy makers, civil society and future research on the sustainability of possible mCDR deployment trajectories.

The post-doctoral project will be carried out under the joint supervision of Adrien Comte (research fellow at IRD, UMR LEMAR) and Manuel Bellanger (researcher at Ifremer, UMR AMURE).

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Comprehensive model of environmental degradation assessment

Published 17 March 2025 Science Closed
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This study explores the development of a comprehensive techno-economic model of environmental degradation based on the ReCiPe2016 approach named Financial Developed ReCiPe (FDR). The FDR considers cause-and-effect pathways of environmental degradation by ocean acidification, floods, acid rain, malnutrition, forest destruction, and waste more than the ReCiPe2016 in the midpoint and the environmental properties in the endpoint by considering tourism potential and intergenerational benefits. This model quantifies environmental degradation by the functions of fate factors (FF), effect factors (EF), exposure factors (XF), and economic impacts. These functions are developed for added cause-and-effect pathways, and the results were verified based on real studies. The uncertainties are considered by Individualist, Hierarchist, and Egalitarian perspectives, and the Monte Carlo Simulation (MCS) method is used to estimate the uncertainty level of variables. The results indicate the acceptability of the findings for the 20–1000-year infinite time horizon is about 13–38% variation. The FDR reveals significant deviations in the Hierarchist perspective compared to the ReCiPe2016; non-cancer diseases due to stratospheric ozone depletion and malnutrition by global warming are increased by approximately 17% and 13%, respectively. Each hectare of forest destruction’s impact on global warming, tourism, and timber resources equates to annual emission of 86 tons of CO2, 426 tons of PM2.5, and 1540 tons of crude oil, respectively. The ocean acidification effects from CO2 emissions compared to SO2 and terrestrial acidification, contributing about 0.03% in the Hierarchist perspective. Finally, the FDR model bridges the existing gap in lifecycle impact assessment (LCIA) in energy-intensive industries such as petrochemical industries.

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Combined uranium-series and trace elements analysis in cold seep bivalves: possibility in hundred-year-scale reconstruction of deep-sea temperature and acidification

Published 17 March 2025 Science Closed
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Despite the pivotal role of deep-sea in the global climate system, effective technology is still limited for reconstructing the key parameters of deep-sea environment such as temperature and acidification, especially at the hundred-year scale. In this study, we assessed the robustness and reliability of using bivalve shells in reconstructing cold seep environments. A significant heterogeneous distribution of trace elements was observed in the shells of clams and mussels from Formosa and Haima cold seeps even if they were collected from the same site, which was caused mainly by the environmental variables rather than physiological characters. The results of the principal component analysis revealed different trace elements ratios in the shell were associated with seepage. In particular, Sr/Ca was identified as a reliable proxy for temperature reconstruction, which performed better than oxygen isotopes. Na/Ca and U/Ca are potential proxies for cold seep acidification, but further validation is needed before their practical application. The age bias using the U-series dating method resulted from high 232Th and low initial 230Th/232Th rather than from alpha-recoil processes. The median ages assigned to mussels from the F and Haima cold seeps were 229.5 and 323.5 years, respectively. The lifespan of clams from the Haima cold seep was too short to date accurately. We proposed to conduct feasibility verification and error correction to enhance the method performance in reconstructing the hundred-year evolution of cold seep environment in the South China Sea.

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GOA-ON biology working group webinar

Published 17 March 2025 Events Closed

The Biology Working Group of GOA-ON was formed in 2015 with the mission to bridge chemical and biological changes associated with ocean acidification. Over the years, it worked on multiple tasks to (i) inform the chemical monitoring program about the biological needs; (ii) evaluate the needs and requirement of a biological monitoring program; and (iii) develop a theoretical framework linking chemical changes to biological response. Some of this work was recently published (Widdicombe et al. 2023) opening the way to new approaches for chemical and biological monitoring. The working group is now exploring new avenues on current and best practices to evaluate the impact of ocean acidification on biodiversity. This presentation will summarize the activities of the working group and offer to the community (chemists, biologists, modelers) an opportunity to contribute to some of the tasks.

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Between shells and seas: effects of ocean acidification on calcification and osmoregulation in yellow clam (Amarilladesma mactroides)

Published 14 March 2025 Science Closed
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Highlights

  • Decline in ocean pH due to increased CO2 is threatening the physiology of marine organisms.
  • Yellow clams (Amarilladesma mactroides) were exposed to ocean acidification and hypersaline stress for 96 hours to assess biomarkers of calcification and osmotic balance.
  • OA reduced Ca2+-ATPase activity in the mantle, damaging mineralized structures.
  • Elevated salinity increases carbonic anhydrase and Na+/K+-ATPase activity in the gills.
  • Increased carbonic anhydrase activity in the mantle may help maintain acid-base balance in the species.

Abstract

The decline in ocean pH due to rising CO2 levels is a critical factor impacting marine ecosystems. Ocean acidification (OA) is expected to negatively affect various organisms, particularly those with mineralized structures. While the effects of OA on the calcification of shells and exoskeletons are documented, the impact on homeostatic processes, such as osmoregulation, is less understood. Osmoregulation is vital for maintaining water and salt balance within marine organisms, crucial for their survival and physiological functions. Acidification may alter ion exchange mechanisms, affecting the regulation of ions. In this study, we evaluated the effects of intermediate OA (pH 7.6) with or without hypersaline stress (35‰) on calcification and osmotic balance biomarkers in the bivalve Amarilladesma mactroides after 96 hours of acute exposure. We found that pH did not affect hemolymph osmolality or extracellular Ca2+ concentration. However, OA impaired the bivalve’s ability to maintain its mineralized structures by decreasing Ca2+-ATPase enzyme activity in the mantle. The increase in carbonic anhydrase activity indicated a specific response to maintain acid-base balance in the tissue, i.e., compensating for the effects of acidification by neutralizing CO2 accumulation and stabilizing internal pH. In the gills, both enzymes showed increased performance under higher salinity and reduced pH. Exposure to less alkaline pH inhibited carbonic anhydrase and Na+/K+-ATPase activity, potentially affecting the regulation of essential inorganic osmolytes.

Continue reading ‘Between shells and seas: effects of ocean acidification on calcification and osmoregulation in yellow clam (Amarilladesma mactroides)’

Alpena UR2 partners with NOAA for acidification project

Published 14 March 2025 Media coverage Closed

The Alpena High School Underwater Research Robotics (UR2) team collaborated last summer with researchers at the National Oceanic and Atmospheric Administration’s Thunder Bay National Marine Sanctuary to address the issue of increased acidification in the Great Lakes.

The team discovered that the surge in acidity is caused by the absorption of carbon dioxide (CO2) from activities such as fossil fuel combustion, leading to a decrease in lake and ocean waters’ potential hydrogen (pH) levels.

The Great Lakes Environmental Research Lab and TBNMS requested that UR2 leverage their marine technology expertise to create a sampler that can fit a remotely-operated vehicle (ROV).

“Our initial approach involved using a Niskin bottle to take water samples attached to the ROV,” a summary of the project, called WARP (Water Acidification Research Project), explains. “Once the ROV reached the designated depth and location, the Niskin bottle was released using the ROV’s grabber. Although this method worked reasonably well, the research protocol stipulated that the water sample had to be sealed at depth and shielded from exposure to surface air.”

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Eukaryotic phytoplankton decline due to ocean acidification could significantly impact global carbon cycle

Published 14 March 2025 Press releases Closed

Princeton University and Xiamen University researchers report that in tropical and subtropical oligotrophic waters, ocean acidification reduces primary production, the process of photosynthesis in phytoplankton, where they take in carbon dioxide (CO2), sunlight, and nutrients to produce organic matter (food and energy).

A six-year investigation found that eukaryotic phytoplankton decline under high CO2 conditions, while cyanobacteria remain unaffected. Nutrient availability, particularly nitrogen, influenced this response.

Results indicate that ocean acidification could reduce primary production in oligotrophic tropical and subtropical oceans by approximately 10%, with global implications. When extrapolated to all affected low-chlorophyll ocean regions, this translates to an estimated 5 billion metric tons loss in global oceanic primary production, which is about 10% of the total carbon fixed by the ocean each year.

The research is published in the journal Proceedings of the National Academy of Sciences.

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Eukaryotic phytoplankton drive a decrease in primary production in response to elevated CO2 in the tropical and subtropical oceans

Published 14 March 2025 Science Closed
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Significance

Marine phytoplankton, which contribute ~45% of global net primary production, are projected to be affected by ongoing ocean acidification (OA). However, the response of phytoplankton to acidification is not well constrained in ultraoligotrophic tropical and subtropical oceans where small (<20 µm) phytoplankton dominate. By conducting onboard microcosm experiments, we found community-level primary production decreased consistently following CO2 enrichment in the North Pacific Subtropical Gyre and northern South China Sea, while no significant changes were observed at the northernmost boundary of the subtropical gyre. Eukaryotic phytoplankton but not cyanobacteria were key drivers of these responses which occur primarily under nitrogen limitation. These findings enhance our understanding of OA impacts on phytoplankton and marine productivity in a changing climate.

Abstract

Ocean acidification caused by increasing anthropogenic CO2 is expected to impact marine phytoplankton productivity, yet the extent and even direction of these changes are not well constrained. Here, we investigate the responses of phytoplankton community composition and productivity to acidification across the western North Pacific. Consistent reductions in primary production were observed under acidified conditions in the North Pacific Subtropical Gyre and the northern South China Sea, whereas no significant changes were found at the northern boundary of the subtropical gyre. While prokaryotic phytoplankton showed little or positive responses to high CO2, small (<20 µm) eukaryotic phytoplankton which are primarily limited by low ambient nitrogen drove the observed decrease in community primary production. Extrapolating these results to global tropical and subtropical oceans predicts a potential decrease of about 5 Pg C y−1 in primary production in low Chl-a oligotrophic regions, which are anticipated to experience both acidification and stratification in the future.

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Carbonate chemistry and CO2 dynamics in the Persian Gulf

Published 14 March 2025 Science Closed
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Highlights

  • The T-S diagram identifies four distinct water types in the Persian Gulf study area.
  • Alkalinity loss equals 31 Mt. CaCO3 or 3.72 Mt. inorganic carbon deposited annually.
  • A ΔOrgC:ΔCaCO3 ratio of 2.6:1 indicates higher photosynthesis over calcification.
  • Dissolved inorganic carbon and total alkalinity, dominate the pCO2 distribution.
  • 85 % of surface waters of the Persian Gulf acted as CO2 sinks in late summer.

Abstract

This study examines the carbonate chemistry of the Persian Gulf within the Iranian Exclusive Economic Zone, using datasets collected during the PGE2102 expedition in September 2021. The water column was stratified, with a warm, oxic upper layer (0–25 m: 33.2 °C, salinity 38.9 psu, O2 177 μmol/kg) and a cooler, low-oxygen deep layer (> 25 m: 24.4 °C, salinity 40.2 psu, O2 94.3 μmol/kg). Four water types were identified: Indian Ocean Surface Water (IOSW), Surface Persian Gulf Water (Surface-PG), Deep Persian Gulf Water (Deep-PG), and Northwest Persian Gulf Water (NW-PG). The lowest normalized alkalinity (NAT) was found in NW-PG (2427 ± 29 μmol/kg), suggesting alkalinity loss, while IOSW exhibited the highest NAT (2551 ± 9 μmol/kg). Deep-PG had lower NAT (2460 ± 18 μmol/kg) than surface waters, with surface NAT decreasing westward. Organic matter decomposition in Deep-PG resulted in the lowest pH (7.924 ± 0.030) and highest pCO2 (592.8 ± 47 μatm). Surface waters showed reduced dissolved inorganic carbon (DIC ~2047 μmol/kg) and undersaturated pCO2 (403.9 ± 69 μatm) due to photosynthesis. Hypoxic zones in western and central areas exhibited elevated DIC (up to 2305.6 μmol/kg) and the lowest pH (7.832), reflecting remineralization. Calcium carbonate precipitation contributed to significant alkalinity losses (66.2 μmol/kg), translating to 31 million tons of annual deposition. A ΔOrgC:ΔCaCO3 ratio of 2.6:1 in surface waters suggests higher photosynthetic activity relative to calcification. Despite localized pCO2 hotspots, 85 % of surface waters acted as CO2 sinks, highlighting unique carbonate dynamics shaped by stratification, biogeochemical processes and regional conditions.

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Future ocean guardians: young scientists trained in Monaco to tackle marine threats

Published 13 March 2025 Media coverage Closed

Monaco is once again at the forefront of marine conservation, hosting the second IAEA Winter School on Ocean Acidification and Multiple Stressors this past November. Over two weeks, a group of early-career scientists from around the world got hands-on experience and expert guidance on how to protect our oceans from rising threats like climate change, pollution, and acidification.

The world’s oceans are under pressure like never before, with human activities causing ripple effects that threaten marine life and coastal communities. Overfishing, pollution, and shifting ocean chemistry don’t just act alone—their combined effects can be far worse than expected, making it even harder to predict and prevent damage. That’s where this program steps in, training the next generation of marine scientists to understand these complex interactions and find solutions to protect ocean ecosystems.

Bringing together 12 young researchers from 11 countries, the Winter School mixed cutting-edge science with real-world applications. Participants learned to distinguish between different types of ocean stressors and conducted lab experiments on coral health, investigating how acidification, warming waters, and pollutants like lithium impact marine life. Their findings will contribute to a global research effort aimed at better predicting and mitigating these effects.

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Council adopts resolution on ocean acidification and hypoxia 

Published 13 March 2025 Web sites and blogs Closed
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A Resolution on Ocean Acidification and Hypoxia was adopted by the Ocean Protection Council at its March 3, 2025 Council meeting to elevate and communicate the state’s commitment to addressing ocean acidification and hypoxia (OAH). The actions within this Resolution reflect and build upon ongoing efforts to understand and mitigate OAH, given the potential for OAH to cause large or irreversible effects on California’s coast and ocean. 

Over the past decade, OPC made significant investments to advance understanding of OAH off California’s coast, consistent with the West Coast OAH Science Panel Major Findings, Recommendations, and Actions and California Ocean Acidification Action Plan. This includes the development of a coupled physical-biogeochemical model for the West Coast to help managers better predict and understand the impacts of OAH in California. The model also assesses the extent to which local nutrient levels exacerbate acidified and hypoxic ocean conditions, leading to waters that are too acidic or lack sufficient oxygen to support vulnerable marine life.  Recent model results have shown that in the Southern California Bight, land-based nutrient inputs are contributing to OAH and impacting the health of California’s marine environment, with implications for ecologically and economically important marine species. OPC continues to pursue additional questions to better understand these impacts, advance monitoring of OAH off California’s coast, and expand the state’s understanding of OAH along the entire coast of California.  

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Impact of simulated pH conditions on phenotypic expression in shrimp pathogenic and non-pathogenic Vibrio campbellii strains

Published 13 March 2025 Science Closed
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Environmental pH fluctuation in oceanic and marine ecosystems can significantly impact the distribution and behavior of pathogenic Vibrio species, including their interactions with marine invertebrates such as crustaceans. This study focused on Vibrio campbellii, a common shrimp pathogen, and its phenotypic responses to varying pH conditions. Both pathogenic strain HY01 and non-pathogenic strain ATCC BAA-1116 were cultured in 30 pL/L Luria-Bertani Sea Salt under 3 pH conditions, including pH 6 (slightly acidic), pH 8 (representing the oceanic pH), and pH 9 (alkaline). Growth patterns and phenotypic traits were evaluated. Results revealed no significant growth difference between the 2 strains under the different pH conditions, although the non-pathogenic strain showed a slight growth reduction at pH 9 during the exponential phase. Both strains were able to buffer environmental pH shifts, adjusting to near-oceanic pH levels (around pH 8). At pH 9, a stressor level for V. campbellii, delays were observed in bioluminescence, biofilm formation, exopolysaccharide production, shrimp surface colonization, motility, and caseinase production, affecting both strains. In contrast, mildly acidic conditions (pH 6) induced the highest expression of several phenotype traits. Statistical analyses indicated significant interactions between strain type and pH levels in influencing phenotypic expression. In conclusion, the pathogenic V. campbellii strain HY01 exhibited greater adaptability and virulence across various pH conditions compared to the non-pathogenic ATCC BAA-1116, emphasizing pH as a critical environmental factor in shaping the growth and pathogenic potential of V. campbellii. Our studies provide valuable insights into managing pH conditions in aquaculture environments to optimize proper shrimp cultivation and prevent cross-contamination of V. campbellii from seawater habitats to farms. These findings provide a physiological profile of Vibrio under pH stress, which can support the development of predictive outbreak models to assess the risk of luminous vibriosis, especially in to seasonal changes and ocean acidification.

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Physiological effects of acute exposure to acidification conditions in embryos of the American lobster (Homarus americanus)

Published 12 March 2025 Science Closed
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Highlights

  • Protein carbonyl concentration increased, and Na+/K+-ATPase activity decreased with decreasing acute pH in American lobster embryos.
  • Oxygen consumption rate and antioxidant content of embryos increased significantly over development.
  • American lobster embryos were sensitive to acute pH reductions representative of future ocean and coastal acidification.

Abstract

Ocean and coastal acidification are altering carbonate chemistry conditions and inducing physiological stress in marine organisms. Early life history stages of marine invertebrates, including commercially important species like the American lobster (Homarus americanus) may have limited physiological capacity to tolerate changes in carbonate chemistry. Using American lobster embryos, we quantified physiological disturbances caused by acute changes in carbonate chemistry. We exposed freshly isolated lobster embryos to conditions ranging from 6.94 to 8.07 pH for 24 h at three points during embryo development. With more extreme conditions of acidification, protein carbonyl concentration (indicative of cellular damage from oxidative stress) increased, and Na+/K+-ATPase activity (associated with acid-base regulation) decreased at all stages of development examined. Although oxygen consumption rate and ferric-reducing antioxidant potential both increased over the course of embryogenesis, we found no evidence that the relationship between pH and these physiological metrics varied during ontogeny. Our results indicate that acid-base regulation and oxidative stress in American lobster embryos may be sensitive to acidification-induced hypercapnia within a 24-h period across a large portion of embryo development.

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On the measurement of ocean acidity with ambient sound

Published 12 March 2025 Science Closed
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The volume-integrated pH of seawater can be determined from the frequency and depth dependence of wind-generated ambient noise in the ocean. Over the 1 − 10 kHz frequency band, three main processes contribute to the acoustic attenuation in seawater: the chemical relaxation of boric acid and magnesium carbonate (< 3 kHz, related to pH), and magnesium sulfate (> 3 kHz, unrelated to pH). When local winds are strong (> 10 m/s), the ambient noise is dominated by locally generated surface noise, which exhibits a depth-independent directionality, and weak frequency and depth-dependent intensity. By measuring the depth-dependence of the spectral slope, the pH may be estimated from a comparison of the experimental data with an analytical model of ambient noise. Measurements of the depth-dependent ambient noise field were carried out in the Philippine Sea, Mariana Trench, and Tonga Trench from 2009 to 2021. The wideband (5 Hz – 30 kHz) acoustic data were recorded with untethered, free-falling, autonomous instrument platforms known as Deep Sound, equipped with two or four hydrophones. In all the data collected, the power spectral slopes became steeper with depth due to the stronger attenuation of high frequencies compared to low frequencies. Depth-averaged pH values, ranging from 7.68 to 8.35, were obtained from eight instrument drops. The noise spectral method, which has the potential for determining the depth-averaged value of pH, with the averaging depth being adjustable, could be suitable for the long-term passive acoustic monitoring of ocean acidity.

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Atlantic surfclams’ response to a changing environment

Published 12 March 2025 Web sites and blogs Closed
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Atlantic surfclams support an important commercial fishery in the Northeast United States. Landings were valued at nearly $41.7 million in 2022. They also improve water quality by removing excess nutrients from the water when they filter and consume plankton. Our research aims to understand how surfclams respond to changes in their environment. 

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NOAA Milford Lab scientists built a model that projects Atlantic surfclam growth based on water temperature and the partial pressure of carbon dioxide. This is a commonly used metric of ocean acidification. This model indicates that ocean acidification will decrease surfclam growth and reproduction by the year 2100, under the Intergovernmental Panel on Climate Change’s high carbon dioxide emission scenario. 

Now we are studying surfclam populations in their natural habitat to see how well real-world observations match these model predictions. We will use data collected in the field to make our growth model for surfclams more accurate.

Research Chemist Matt Poach collecting surfclams from a clam dredge boat in Shinnecock Inlet, Long Island, New York. Behind, crewmembers of the F/V Susan H shovel clams from the dredge to a safe zone for the scientists to collect them. Credit: NOAA Fisheries/Katyanne Shoemaker

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Research Questions

  • Does temperature or carbonate chemistry of either the seawater or the water within the sediment affect the growth of surfclams?
  • Do differences between the subspecies affect the relationship between environmental conditions and growth?
  • How well do our lab-based growth models predict surfclam growth rates in the field based on the environmental conditions of their habitat?

…

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OA-ICC bibliographic database updated

Published 11 March 2025 Science Closed

An updated version of the OA-ICC bibliographic database is available online.

The database currently contains 9288 references and includes citations, abstracts and assigned keywords. Updates are made every month.

The database is available as a group on Zotero. Subscribe online or, for a better user experience, download the Zotero desktop application and sync with the group OA-ICC in Zotero. Please see the “User instructions” for further details.

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Research on Atlantic surface pCO2 reconstruction based on machine learning

Published 11 March 2025 Science Closed
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Highlights

  • The XGBoost machine learning model has been refined, leading to a superior prediction of atmospheric carbon dioxide partial pressure over the Atlantic Ocean.
  • We introduced the GeoDetector, a spatial statistical analysis method, to quantitatively assess the influence of various factors on the atmospheric carbon dioxide partial pressure over the ocean surface.
  • Comprehensive validation ensures the robustness and reliability of the XGBoost model in this region.
  • Investigations into the atmospheric carbon dioxide partial pressure over the Atlantic Ocean offer valuable insights into global marine ecosystems.

Abstract

Ocean acidification is transforming marine ecosystems at an unprecedented rate, which in turn requires the estimation of sea surface carbon dioxide partial pressure (pCO2) as a crucial metric to gauge acidification. This has substantial implications for marine resource assessment and management, marine ecosystems, and global climate change research. This study utilizes SOCAT cruise survey data to assess the accuracy of global sea surface pCO2 products offered by Copernicus Marine Service and the Chinese Academy of Sciences Ocean Science Research Center. Through the application of a geographic information analysis method—geographical detector—the study quantitatively reveals the significance of environmental influencing factors, such as longitude, latitude, sea surface 10 m wind speed (U10), total precipitation (TP), evaporation (E), and significant height of combined wind waves and swell (SHWW), in the reconstruction of sea surface pCO2. Subsequently, various machine learning models, which include convolutional neural network (CNN), back propagation neural network (BP), long short-term memory network (LSTM), extreme learning machine (ELM), support vector regression (SVR), and extreme gradient boosting tree (XGBoost), are used to reconstruct the monthly sea surface pCO2 data for the Atlantic Ocean from 2001 to 2020 to investigate the potential and suitability of high-precision reconstruction of the sea surface pCO2 dataset for this sea area. The findings indicate that: (1) The geographical detector effectively quantifies the contribution of various environmental factors used in sea surface pCO2 reconstruction. Notably, the Copernicus pCO2 and CODC-GOSD pCO2 contribute the most, with both contributing ∼0.72. These are followed by TP, latitude, longitude, SHWW, U10, and E. (2) After comprehensive data testing, the six machine learning models select the optimal hyperparameters for reconstruction. Among these, the XGBoost model notably improved the quality of the original dataset when using Copernicus pCO2 and CODC-GOSD pCO2 products in conjunction with SHWW, U10, and TP environmental variable data. Compared with SOCAT data, the overall reconstruction accuracy in the Atlantic Ocean reached an impressive 94 %, outperforming the standalone use of either Copernicus pCO2 or CODC-GOSD pCO2 products. Furthermore, the XGBoost model demonstrated strong applicability in regions with numerous outliers, maintaining a reconstruction accuracy of ≥95 %. (3) Stability test results reveal that the XGBoost model exhibits low sensitivity to uncertainties in all input variables. This indicates that the model can accommodate environmental data errors induced by abrupt changes in marine environments. Such robustness enhances its reliability in sea surface pCO2 reconstruction. The reconstruction of the Atlantic sea surface pCO2 is conducive to the assessment of global ocean acidification and provides a theoretical basis for the sustainable development of the marine environment.

    Continue reading ‘Research on Atlantic surface pCO2 reconstruction based on machine learning’

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