Technical meeting on ocean acidification meta-analyses using the Ocean Acidification International Coordination Centre bibliographic database and other data resources

Date: 13 – 17 February 2023

Location: The event will be held virtually via Microsoft Teams

Deadline for applications: 12 January 2023

Introduction: Ocean acidification is a direct consequence of the release of anthropogenic CO2 into the atmosphere. It has been a major area of work of the IAEA though the Ocean Acidification International Coordination Centre (OA-ICC). Over the years, the OA-ICC has developed key resources for the ocean acidification community including a bibliographic database and a data compilation which facilitates data comparison and meta-analyses. The use of these resources is increasingly important to synthetize the present knowledge, test new hypotheses and identify new research directions. Moreover, it provides a unique opportunity to create new knowledge for research teams in developing countries with limited access to field and laboratories. The purpose of the event is to promote the use of the OA-ICC databases through (i) teaching of the basics of synthesis and meta-analysis methodologies; (ii) identification of key questions that can be answered through synthesis and meta-analysis using the OA-ICC resources; and (iii) work on individual meta-analysis projects. Participants will be given some support beyond the training to develop their own meta-analysis projects.

Objectives: The Ocean Acidification International Coordination Centre (OA-ICC) promotes data access and sharing within the ocean acidification research community. The OA-ICC provides access to two online databases:

  • A bibliographic database which currently includes more than 9,800 references with custom       OA-ICC keywords and is shared using Zotero and pCloud.
  • A data compilation which facilitates data comparison and meta-analyses. To easily filter and access relevant biological response data from this compilation, a user-friendly portal was developed.

During this workshop, participants will learn:

  • Basics of the different synthesis and meta-analysis methodologies (narrative, semi-quantitative, quantitative) through lectures and critical evaluation of existing published material.
  • How to navigate the OA-ICC databases and how to use these resources to test new hypotheses.
  • Identify and develop their own questions and identify collaborators within the course.

The training will continue after the course through a mentoring program. Each participant will have the opportunity to work with an expert on their individual project with the goal to publish meta-analysis articles relevant for their region.

Target audience: The course is open to 10 trainees. Priority will be given to early-career scientists with experience in ocean acidification and marine biology. At least one publication in the field of ocean acidification is required. Participants should have an interest in data analyses and syntheses as well as some time to invest into a meta-analysis project beyond the course.

Working language(s): English

Expected outputs: Increased capacity to perform meta-analyses and increased networking among scientists working on ocean acidification. Initiate/deepen connections with international networks such as the Global Ocean Acidification Observing Network (GOA-ON; Participants will also work on personal projects, developing strategies for their own research and a data-based projects using data resources from the OA-ICC.

Structure: The training will include lectures and guest lectures and assignments in smaller groups (the level will depend on the basic knowledge of the selected participants). Subjects to be covered include:

  • Best-practices in ocean acidification research and monitoring
  • State-of-the-art in the field of ocean acidification and other global drivers
  • Theory on different types of meta-analyses and synthesis
  • Data extraction from OA-ICC databases, and other sources
  • Standardization and data analysis
  • Scientific writing
Continue reading ‘Technical meeting on ocean acidification meta-analyses using the Ocean Acidification International Coordination Centre bibliographic database and other data resources’

Ten years of the Ocean Acidification International Coordination Centre (video)

2022 marks the tenth anniversary of the IAEA’s Ocean Acidification International Coordination Centre, which uses nuclear research to combat the damage that climate change is causing to our marine ecosystems. Ambassador Holgate visited the OA-ICC labs in Monaco to celebrate this important milestone.

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OA-ICC bibliographic database updated

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

The database currently contains 9,937 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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Eckerd College professor publishes paper on sharing research about health of Florida stone crabs

Assistant Professor of Marine Science Philip Gravinese works with students to study stone crabs in Tampa Bay.

The way Philip Gravinese, Ph.D., sees it, research is important not just for what can be discovered but for how that information can be shared.

In keeping with that philosophy, Gravinese, an Eckerd College assistant professor of marine science, recently co-authored a paper titled “Do pH-Variable Habitats Provide Refuge for Stone Crabs from Coastal Acidification?” It was published Nov. 15 in the journal Oceanography.

“The paper is a lesson developed for educators that is based on some of the ongoing research I’ve been doing near Fort De Soto Park,” Gravinese explains. “In this work we are looking at stone crab reproductive success between sandy habitats (narrow pH range) and seagrass habitats (wider pH range) to see if the pH range between those habitats provides the stone crab with any reproductive advantage under future climate change reductions in seawater pH.”

The project is being funded by the Tampa Bay Estuary Program.

Last year, Gravinese and two researchers from Louisiana State University were awarded a four-year, $922,000 grant from the National Science Foundation to study the impact of climate change on stone crabs. The goal is to investigate and model how rapidly changing ocean temperatures and pH levels disrupt stone crab larval development, behavior and dispersal among habitats along the Florida coasts. Gravinese’s previous work has shown that stone crabs can be sensitive to environmental stressors throughout their larval development.

Continue reading ‘Eckerd College professor publishes paper on sharing research about health of Florida stone crabs’

Do pH-Variable habitats provide refuge for stone crabs from coastal acidification?


This guided, inquiry-based, hands-on lesson uses data from a local monitoring station in Tampa Bay, Florida, to guide students toward understanding how coastal acidification may impact the reproductive success of the Florida stone crab, an important regional fishery. The objectives of the lesson are for students to: (1) determine how pH varies between different habitats, (2) determine how pH can affect the reproductive success of an important commercial fishery, the Florida stone crab, and (3) evaluate whether exposure to variable seawater pH results in greater reproductive success in stone crabs relative to individuals that are not exposed to pH variability.


This lesson is designed for undergraduates in introductory-level biology, marine biology, environmental chemistry, and oceanography courses. The activities introduce students to ocean acidification relationships associated with diel fluctuations in pH in benthic habitats like seagrass and sand. The lesson also correlates reductions in seawater pH to the reproductive success of a commercially important species, the Florida stone crab.

Continue reading ‘Do pH-Variable habitats provide refuge for stone crabs from coastal acidification?’

Carbon and nutrient cycling in Antarctic landfast sea ice from winter to summer

Seasonal cycling in carbon, alkalinity, and nutrients in landfast sea ice in Hangar Cove, Adelaide Island, West Antarctic Peninsula, were investigated during winter, spring, and summer 2014–2015. Temporal dynamics were driven by changes in the sea-ice physicochemical conditions, ice-algal community composition, and organic matter production. Winter sea ice was enriched with dissolved inorganic carbon (DIC) and inorganic nutrients from organic matter remineralization. Variations in alkalinity (Alk) and DIC indicated that abiotic calcium carbonate (ikaite) precipitation had taken place. Relative to other nutrients, low phosphate (PO4) concentrations potentially resulted from co-precipitation with ikaite. Seawater flooding and meltwater induced variability in the physical and biogeochemical properties in the upper ice in spring where nutrient resupply supported haptophyte productivity and increased particulate organic carbon (POC) in the interstitial layer. Rapid nitrate (NO3) and DIC (< 165 μmol kg−1) uptake occurred alongside substantial build-up of algal biomass (746 μg chlorophyll a L−1) and POC (6191 μmol L−1) during summer. Silicic acid drawdown followed NO3 depletion by approximately 1 month with a shift to diatom-dominated communities. Accumulation of PO4 in the lower ice layers in summer likely resulted from PO4 released during ikaite dissolution in the presence of biofilms. Increased Alk : DIC ratios in the lower ice and under-ice water suggested that ikaite dissolution buffered against meltwater dilution and enhanced the potential for atmospheric CO2 uptake. This study revealed strong seasonality in carbon and nutrient cycling in landfast sea ice and showed the importance of sea ice in biogeochemical cycling in seasonally ice-covered waters around Antarctica.

Continue reading ‘Carbon and nutrient cycling in Antarctic landfast sea ice from winter to summer’

Accelerated accumulation of anthropogenic CO2 drives rapid acidification in the North Pacific subtropical mode water during 1993−2020


Recent studies suggest that the formation and motion of the North Pacific subtropical mode water (STMW) play an important role in oceanic uptake, transport and storage of anthropogenic CO2 (CANT). However, the variability of STMW acidification rate and its control mechanisms remain unclear. Here we show that the STMW acidification rate during 2005−2020 is about two times of that during 1993−2005, which is due to the cooling-driven enhanced CANT accumulation in the formation waters in the recent period. The rapid rates of CANT accumulation and acidification are consistently observed in the entire region across 137°−149°E regulated by STMW transport. Moreover, the tracer-based (Δ14C and δ13C) analyses also indicate that the accelerated accumulation of CANT could be traced back to the surface formation waters via STMW formation. The vertical and horizontal consistencies imply the memory function of mode waters in retaining the anthropogenic carbon fingerprint during its formation and transport.

Key Points

  • The decline rates of pH and Ωarag in the North Pacific subtropical mode water (STMW) during 2005−2020 are ∼2 times of that during 1993−2005
  • The faster STMW acidification is attributed to the accelerated accumulation of anthropogenic CO2 (CANT) in the formation waters
  • The rapid rates of CANT accumulation and acidification are consistently observed across the 137°−149°E regulated by STMW transport
Continue reading ‘Accelerated accumulation of anthropogenic CO2 drives rapid acidification in the North Pacific subtropical mode water during 1993−2020’

GOOD-OARS-CLAP-COPAS summer school 2023: application deadline extended!

Location: CEAZA & University of Coquimbo

Dates: 6 – 12 November 2023




The CLAP Project


The last IPCC report confirms the deleterious effects of rising temperatures and decreasing pH and oxygen in the coastal and open ocean ecosystems, calling for enhancing our capacity to predict the ocean state. The GOOD-OARS-CLAP-COPAS International Summer School 2023 is designed to prepare the next generation of ocean scientists that will engage in multidisciplinary research and increase our understanding on the response of marine ecosystems in the next decades.


The Summer School aims to teach the skills and knowledge of the many disciplines needed to understand the ocean and atmospheric processes involved in ocean deoxygenation and acidification with a focus on Eastern Boundary Upwelling systems. It will expose graduate and doctoral students and early-career scientists to recent developments and methodologies in the study of biogeochemical and physical feedbacks between the ocean and atmosphere in a changing environment.


The GOOD-OARS-CLAP-COPAS summer school is opened to graduate and doctoral students, and early career scientists interested in interacting with world leading experts in the field in a friendly atmosphere, and enhancing their understanding of the processes constraining the future state of the oceans and environmental risks to marine habitats and ecosystems.


Please send an email to if you have any questions or need further assistance regarding the Summer School.

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Coral reef carbonate accretion rates track stable gradients in seawater carbonate chemistry across the U.S. Pacific Islands

The U.S. Pacific Islands span a dramatic natural gradient in climate and oceanographic conditions, and benthic community states vary significantly across the region’s coral reefs. Here we leverage a decade of integrated ecosystem monitoring data from American Samoa, the Mariana Archipelago, the main and Northwestern Hawaiian Islands, and the U.S. Pacific Remote Island Areas to evaluate coral reef community structure and reef processes across a strong natural gradient in pH and aragonite saturation state (Ωar). We assess spatial patterns and temporal trends in carbonate chemistry measured in situ at 37 islands and atolls between 2010 and 2019, and evaluate the relationship between long-term mean Ωar and benthic community cover and composition (benthic cover, coral genera, coral morphology) and reef process (net calcium carbonate accretion rates). We find that net carbonate accretion rates demonstrate significant sensitivity to declining Ωar, while most benthic ecological metrics show fewer direct responses to lower-Ωar conditions. These results indicate that metrics of coral reef net carbonate accretion provide a critical tool for monitoring the long-term impacts of ocean acidification that may not be visible by assessing benthic cover and composition alone. The perspectives gained from our long-term, in situ, and co-located coral reef environmental and ecological data sets provide unique insights into effective monitoring practices to identify potential for reef resilience to future ocean acidification and inform effective ecosystem-based management strategies under 21st century global change.

Continue reading ‘Coral reef carbonate accretion rates track stable gradients in seawater carbonate chemistry across the U.S. Pacific Islands’

Transcriptome analysis of hepatopancreas in penaeus monodon under acute low pH stress

The decrease of seawater pH can affect the metabolism, acid-base balance, immune response and immunoprotease activity of aquatic animals, leading to aquatic animal stress, impairing the immune system of aquatic animals and weakening disease resistance, etc. In this study, we performed high-throughput sequencing analysis of the hepatopancreas transcriptome library of low pH stress penaeus monodon, and after sequencing quality control, a total of 43488612–56271828 Clean Reads were obtained, and GO annotation and KEGG pathway enrichment analysis were performed on the obtained Clean Reads, and a total of 395 DEGs were identified. we mined 10 differentially expressed and found that they were significantly enriched in the Metabolic pathways (ko01100), Biosynthesis of secondary metabolites (ko01110), Nitrogen metabolism (ko00910) pathways, such as PIGA, DGAT1, DGAT2, UBE2E on Metabolic pathways; UGT, GLT1, TIM genes on Biosynthesis of secondary metabolites; CA, CA2, CA4 genes on Nitrogen metabolism, are involved in lipid metabolism, induction of oxidative stress and inflammation in the muscular body of spot prawns. These genes play an important role in lipid metabolism, induction of oxidative stress and inflammatory response in the muscle of the shrimp. In summary, these genes provide valuable reference information for future breeding of low pH-tolerant shrimp.

Continue reading ‘Transcriptome analysis of hepatopancreas in penaeus monodon under acute low pH stress’

Register for the December GOA-ON webinar

Topic: GOA-ON Webinar

Description: Please join GOA-ON for this month’s webinar, “Carbon cycle monitoring in the extreme latitudes: the Southern Ocean and Arctic Ocean” on December 14, 3pm UTC. The webinar will feature presentations by Dr. Margaret Ogundare and Dr. Mohamed Ahmed. The speakers will span topics such as increasing the spatial and temporal observations of the Southern Ocean, the Arctic marine carbon sink, as well as neural network machine learning. These research topics will address how to constrain the carbonate system in regions that remain under surveyed due to their remoteness and seasonality.

Time: Dec 14, 2022 05:00 PM in Paris


photo of Margaret Ogundare

Margaret Ogundare, Lecturer @Department of Marine Science and Technology, Federal University of Technology, Akure Nigeria

Dr Ogundare received a PhD in Earth Sciences in 2020 with thesis title Carbon Solubility Pump: Carbon Dioxide Flux and Ocean Acidification Below Southern Africa from Stellenbosch University, South Africa. She is currently working on writing more journal papers from her PhD thesis and on a project with “The Ocean Foundation” on Baseline coastal ocean acidification monitoring in the Gulf Guinea.

photo of Mohamed Ahmed

Mohamed Ahmed, Higher Education Specialist @Esri Canada

Mohamed received his PHD from the University of Calgary in 2020 where he focused on budgeting the marine carbon sink in the Canadian Arctic waters. Then he did two-short postdocs at University of Calgary and University of Victoria studying air-sea gas exchange and impacts of climate change. Dr. Ahmed’s research interests lie in studying marine biogeochemistry and sea-air gas fluxes using observations and geospatial technologies. During his PhD, Dr. Ahmed was able to budget the marine carbon sink in 20% of the Arctic Ocean Surface area. Currently, he is developing various techniques such as neural network machine learning to scale up the sparse field observations of dissolved gases such as CO2 and O2 to regional scales.

Registration link

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Engineered nanoparticles could help store excess carbon dioxide in the ocean

Seeding the oceans with nano-scale fertilizers could create a much-needed, substantial carbon sink. Credit: Stephanie King | Pacific Northwest National Laboratory

The urgent need to remove excess carbon dioxide from Earth’s environment could include enlisting some of our planet’s smallest inhabitants, according to an international research team led by Michael Hochella of the Department of Energy’s Pacific Northwest National Laboratory.

Hochella and his colleagues examined the scientific evidence for seeding the oceans with iron-rich engineered fertilizer particles near ocean plankton. The goal would be to feed phytoplankton, microscopic plants that are a key part of the ocean ecosystem, to encourage growth and carbon dioxide (CO2) uptake. The analysis article appears in the journal Nature Nanotechnology.

“The idea is to augment existing processes,” said Hochella, a Laboratory fellow at Pacific Northwest National Laboratory. “Humans have fertilized the land to grow crops for centuries. We can learn to fertilize the oceans responsibly.”

In nature, nutrients from the land reach oceans through rivers and blowing dust to fertilize plankton. The research team proposes moving this natural process one step further to help remove excess CO2 through the ocean. They studied evidence that suggests adding specific combinations of carefully engineered materials could effectively fertilize the oceans, encouraging phytoplankton to act as a carbon sink.

More information: Peyman Babakhani et al, Potential use of engineered nanoparticles in ocean fertilization for large-scale atmospheric carbon dioxide removal, Nature Nanotechnology (2022). DOI: 10.1038/s41565-022-01226-w

Continue reading ‘Engineered nanoparticles could help store excess carbon dioxide in the ocean’

O2 and CO2 responses of the synaptic period to under-ice phytoplankton bloom in the eutrophic Razdolnaya River estuary of Amur Bay, the Sea of Japan

Hydrological conditions are an important factor for aquatic ecosystems. Their contribution to stimulating phytoplankton bloom in eutrophic estuaries is not quite clear. We present the results of an outbreak of a phytoplankton bloom event observed in the eutrophic Razdolnaya R. estuary in 2022 from January 22 to February 23, when the estuary was covered by ice. The bloom spreads over 21 km from the river mouth bar to upstream in the near-bottom layer below the halocline. The Chl-a concentration in the bloom area increased from 15 to 100 μg/L, and the dissolved oxygen concentration from 350 to 567 μmol/kg at a rate of 11 μmol/(kg day) over the study period, while the CO2 partial pressure was reduced to 108 µatm in the most oxygen-supersaturated waters. The Thalassiosira nordenskioeldii Cleve sea diatom was the dominant phytoplankton species in the bloom area. The opposite trend was observed near the boundary of the saline water wedge penetration over 29 km from the river mouth bar to upstream where the dissolved oxygen concentration decreased from 140 to 53 μmol/kg over a month, and partial pressure of CO2 reached 4454 μatm. We also present the results obtained in February 2016 before and after a snowfall, when the ability of PAR to penetrate through the ice was impeded by a layer of snow. After the snowfall, photosynthesis in the under-ice water stopped and the oxygen concentration decreased to almost zero due to the microbiological destruction of the phytoplankton biomass. As such, the main effect of phytoplankton bloom is the formation of superoxia/hypoxia (depending on the light conditions), during the period of maximum ice thickness and minimum river discharge. Thus, this study demonstrates that the eutrophication in the future could lead to unstable ecosystems and large synoptic variations of dissolved oxygen and CO2 partial pressure of the estuaries.

Continue reading ‘O2 and CO2 responses of the synaptic period to under-ice phytoplankton bloom in the eutrophic Razdolnaya River estuary of Amur Bay, the Sea of Japan’

Unraveling cellular and molecular mechanisms of acid stress tolerance and resistance in marine species: new frontiers in the study of adaptation to ocean acidification

Graphical abstract


  • OA poses a threat to marine life, although some taxa can tolerate low seawater pH.
  • Different responses at cellular and molecular level observed in marine organisms
  • Role of ABC transporter proteins towards acid stress tolerance and resistance
  • Understanding cellular mechanisms of acid stress tolerance to unravel OA impacts


Since the industrial revolution, fossil fuel combustion has led to a 30 %-increase of the atmospheric CO2 concentration, also increasing the ocean partial CO2 pressure. The consequent lowered surface seawater pH is termed ocean acidification (OA) and severely affects marine life on a global scale. Cellular and molecular responses of marine species to lowered seawater pH have been studied but information on the mechanisms driving the tolerance of adapted species to comparatively low seawater pH is limited. Such information may be obtained from species inhabiting sites with naturally low water pH that have evolved remarkable abilities to tolerate such conditions. This review gathers information on current knowledge about species naturally facing low water pH conditions and on cellular and molecular adaptive mechanisms enabling the species to survive under, and even benefit from, adverse pH conditions. Evidences derived from case studies on naturally acidified systems and on resistance mechanisms will guide predictions on the consequences of future adverse OA scenarios for marine biodiversity.

Continue reading ‘Unraveling cellular and molecular mechanisms of acid stress tolerance and resistance in marine species: new frontiers in the study of adaptation to ocean acidification’

Calcifying organisms, under threat from a combination of ocean warming and acidification

Newswise: Calcifying organisms, under threat from a combination of ocean warming and acidification

A bryozoan, at 32m depth at Signy Island, Antarctica. Credit: David Barnes, British Antarctic Survey

A new study led by the Institut de Ciències del Mar (ICM-CSIC), with colleagues from the British Antarctic Survey, the Institute of Oceanology, the Polish Academy of Sciences and the University of Gdańsk have also participated has revealed that global warming and ocean acidification threaten marine organisms that build their skeletons and shells with calcium carbonate (chalk) such as corals, bryozoans, molluscs, sea urchins or crustaceans.

The work, recently published in the journal Ecography, focuses on organisms with calcium carbonate skeletons from around Antarctica in the Southern Ocean. Calcium carbonate is more soluble in more acidic waters which contain more carbon dioxide (CO2), such as the colder waters of the polar regions, making it harder for these creatures to build their skeletons.

Bryozoans, key for understanding the global change impacts on calcifying organisms

To carry out the study, researchers analysed the skeleton of a group of marine creatures called bryozoans (commonly known as moss animals), which are small filter-feeding invertebrates that live on the seafloor and can create complex habitats that enhance biodiversity.

In this sense, the expert explains that the bryozoan skeletons are made of the two main types of calcium carbonate, calcite or aragonite, but they can also incorporate magnesium, which can make the skeletons more vulnerable to acidification.

Through mineralogical analyses, researchers identified the different types of minerals and determined the levels of magnesium found in Antarctic bryozoan skeletons, creating the largest dataset for Southern Ocean bryozoans ever produced. Then, they included these mineral signatures with existing data from almost 500 species found in the Southern Hemisphere and compared the distribution of the different mineral types and levels of magnesium in their skeletons with the temperature of the seawater that they lived in.

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Temperature as a likely driver shaping global patterns in mineralogical composition in bryozoans: implications for marine calcifiers under global change

The Southern Ocean is showing one of the most rapid responses to human-induced global change, thus acting as a sentinel of the effects on marine species and ecosystems. Ocean warming and acidification are already impacting benthic species with carbonate skeletons, but the magnitude of these changes to species and ecosystems remains largely unknown. Here we provide the largest carbonate mineralogical dataset to date for Southern Ocean bryozoans, which are diverse, abundant and important as carbonate producers, thus making them excellent for monitoring the effects of ocean warming and acidification. To improve our understanding of how bryozoans might respond to ocean warming and acidification, we assess latitudinal and seafloor temperature patterns of skeletal mineralogy using bryozoan species occurrences together with temperature data for the first time. Our findings, combining new mineralogical data with published data from warmer regions, show that the proportions of high-Mg calcite and bimineralic species increase significantly towards lower latitudes and with increasing seawater temperature. These patterns are consistent with the hypothesis that seawater temperature is likely a significant driver of variations in bryozoan mineralogy at a global scale.

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Voltage-gated proton channels explain coccolithophore sensitivity to ocean acidification

Coccolithophores are unicellular photosynthetic plankton that perform extraordinary feats in ionic homeostasis to fabricate intricate nano-patterned plates made of calcium carbonate (CaCO3) crystals called coccoliths (1). Outside marine science communities, coccolithophores are less known than animal calcifiers such as shellfish or the cnidarians that form coral reefs. However, coccolithophores are one of Earth’s greatest biological producers of CaCO3. The production and sinking of coccoliths play complex roles in ocean carbon cycles, helping carry organic carbon to the deep sea as well serving on a geological scale to help the ocean buffer CO2 fluctuations (23). Unlike other calcifying organisms, where precipitation of CaCO3 is extracellular, coccolithophores calcify in special intracellular Golgi-derived coccolith vesicles. To do this, they maintain among the greatest fluxes of Ca2+ and H+ known for any cell ions which would be toxic if allowed to accumulate in the cytoplasm (1). In PNAS, Kottmeier et al. (4) demonstrate how they rely on voltage-gated proton channels to expel H+ released by CaCO3 precipitation, which also offers a way forward to resolving disparate results from two decades of research on coccolithophore sensitivity to ocean acidification.

Approximately a third of human CO2 emissions are absorbed by the ocean, resulting in ocean acidification. As CO2 dissolves in the sea it reacts with water to form carbonic acid, generating H+ (decreasing pH) and perturbing a set of interlocked equilibria involving CO2, HCO3, CO32−, H+, and Ca2+ by increasing [HCO3], decreasing [CO32−], and lowering the saturation states of alternative forms of CaCO3 (5). The inorganic chemistry is complex but comparatively well known. The response of calcifying organisms should be simple to predict if it depended only on the tendency of CaCO3 to precipitate or dissolve in seawater: Organisms such as coccolithophores which produce calcite, the more stable form of CaCO3, should be less sensitive to ocean acidification compared to organisms like many corals which produce less-stable forms such as aragonite.

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Ocean acidification lessons: shell shifts (video)

Ocean Acidification Lessons: Shell Shifts

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Dynamics of greenhouse gases (GHG) in marine vegetation, from seafloor to ocean-atmosphere fluxes (PhD position)

HOST ORGANIZATION: IMEDEA – CSIC – Instituto Mediterráneo de Estudios Avanzados

GROUP LEADER: Dr. Iris E. Hendriks (


Research Project / Research Group Description

Anthropogenic CO2 emissions have caused sea surface temperatures to increase, while this increase of atmospheric CO2 has partly been mitigated by the oceans’ uptake. This uptake has drastic consequences for the marine environment, as it drives a pH decrease in seawater known as ocean acidification (OA). The concentration of other gases besides CO2, responsible for the greenhouse effect (CH4 and N2O) in the marine environment also has a high spatial and temporal variability as a consequence of the physical and biogeochemical processes characteristic of each area. In coastal areas, the balance of GHG gases is particularly variable and, in addition to natural causes, is driven by anthropogenic factors. Determining whether the different coastal regions act as sources or sinks is relevant for establishing global greenhouse gas balances.

The Global Change Research Group (GCR) at IMEDEA (CSIC-UIB), in Mallorca, Spain, has decades of experience in research of the evidence and effects of climate change on coastal ecosystems, in particular in vegetated habitat like seagrass meadows. The group is involved in monitoring the CO2 concentration in atmosphere and surface water since 2008 and other GHGs since 2018. Their main research subject are processes structuring seagrass meadows, but also invasive macrophytes and they harbour valuable background knowledge about evolution of meadow healt and trayectories of ecosystem services of the meadows. The marine component of the group include:

–        Iris E. Hendriks ( CSIC)

–        Núria Marbà (CSIC)

–        Andrea Anton (UIB)

–        Susana Flecha (CSIC)

–        Elvira Mayol (CSIC)

–        Alex Morell (CSIC)

The GCR group has a high scientific output, with publications in prestigious journals. During the last 5 years, the group has formed 10 PhD students. The group’s PhD students usually obtain competitive contracts or positions after completion of their thesis.

Job position description

The proposed research work will focus on different marine compartments in order to get an overall view of the dynamics of GHG in coastal areas. 1) Through the analysis of time-series CO2, CH4 and N2O from three sites in the Archipelago of the Balearic islands (part of the Balearic Ocean Acidification Time Series – BOATS) GHG concentration in surface water will be determined and ocean-atmosphere fluxes calculated. These measurements will be matched to time series of dissolved CO2 from satellite data (i.e. CMEMS – Copernicus) and additional parameters obtained in-situ. Calculations of gas fluxes will be validated by surface measurements using incubation chambers. Seasonal and interannual variability will be determined from the ongoing series (started in 2018) and the drivers that determine this variability (physical and / or biological) will be identified.

2) In order to identify the production/retention of GHGs in the benthic compartment, we will deploy benthic incubations in-situ. Manipulations of organic matter and evaluation of key bacterial communities will determine the link between organic matter deposition, i.e. from WWTPs close to seagrass meadows and CO2/CH4 dynamics in seagrasses and macrophytes. Furthermore we will collection cores for laboratory incubation to validate field rates. Laboratory manipulation of temperature according to IPCC future scenarios should enable a prediction of future emissions in the coastal benthic zone of the Balearic islands.

3) The link between benthic GHG dynamics and transfer to the pelagic water column and eventually atmosphere will be established by concentration profiles of the water column.

To apply: Dr. Iris E. Hendriks (

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Dissolved inorganic carbon export from rivers of Great Britain: spatial distribution and potential catchment-scale controls


  • A survey of DIC was carried out across 41 rivers in Great Britain.
  • Results were examined in relation to land cover and natural gradients across Great Britain.
  • Estimated average yield of DIC from the survey catchments to the sea was 8.13 t ha−1 yr−1.
  • Free CO2 concentrations were strongly linked to catchment macro-nutrient status.
  • Free CO2 yield at was estimated to be 0.56 t C km2 yr−1.


Dissolved inorganic carbon (DIC) fluxes from the land to ocean have been quantified for many rivers globally. However, CO2 fluxes to the atmosphere from inland waters are quantitatively significant components of the global carbon cycle that are currently poorly constrained. Understanding, the relative contributions of natural and human-impacted processes on the DIC cycle within catchments may provide a basis for developing improved management strategies to mitigate free CO2 concentrations in rivers and subsequent evasion to the atmosphere. Here, a large, internally consistent dataset collected from 41 catchments across Great Britain (GB), accounting for ∼36% of land area (∼83,997 km2) and representative of national land cover, was used to investigate catchment controls on riverine dissolved inorganic carbon (DIC), bicarbonate (HCO3) and free CO2 concentrations, fluxes to the coastal sea and annual yields per unit area of catchment. Estimated DIC flux to sea for the survey catchments was 647 kt DIC yr−1 which represented 69% of the total dissolved carbon flux from these catchments. Generally, those catchments with large proportions of carbonate and sedimentary sandstone were found to deliver greater DIC and HCO3 to the ocean. The calculated mean free CO2 yield for survey catchments (i.e. potential CO2 emission to the atmosphere) was 0.56 t C km−2 yr−1. Regression models demonstrated that whilst river DIC (R2 = 0.77) and HCO3 (R2 = 0.77) concentrations are largely explained by the geology of the landmass, along with a negative correlation to annual precipitation, free CO2 concentrations were strongly linked to catchment macronutrient status. Overall, DIC dominates dissolved C inputs to coastal waters, meaning that estuarine carbon dynamics are sensitive to underlying geology and therefore are likely to be reasonably constant. In contrast, potential losses of carbon to the atmosphere via dissolved CO2, which likely constitute a significant fraction of net terrestrial ecosystem production and hence the national carbon budget, may be amenable to greater direct management via altering patterns of land use.

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Seasonal dynamics and annual budget of dissolved inorganic carbon in the northwestern Mediterranean deep convection region

Deep convection plays a key role in the circulation, thermodynamics and biogeochemical cycles in the Mediterranean Sea, considered as a hotspot of biodiversity and climate change. In the framework of the DEWEX (Dense Water Experiment) project, the seasonal cycle and annual budget of dissolved inorganic carbon in the deep convection area of the northwestern Mediterranean Sea are investigated over the period September 2012–September 2013, using a 3-dimensional coupled physical-biogeochemical-chemical modeling approach. We estimate that the northwestern Mediterranean Sea deep convection region was a moderate sink of CO2 for the atmosphere over the study period. The model results show the reduction of CO2 uptake during deep convection, and its increase during the abrupt spring phytoplankton bloom following the deep convection events. We highlight the dominant role of both biological and physical flows in the annual dissolved inorganic carbon budget. The upper layer of the northwestern deep convection region gained dissolved inorganic carbon through vertical physical supplies and, to a lesser extent, air-sea flux, and lost dissolved inorganic carbon through lateral transport and biological fluxes. The region, covering 2.5 % of the Mediterranean, acted as a source of dissolved inorganic carbon for the surface and intermediate water masses of the western and southern Western Mediterranean Sea and could contribute up to 10 and 20 % to the CO2 exchanges with the Eastern Mediterranean Sea and the Atlantic Ocean.

Continue reading ‘Seasonal dynamics and annual budget of dissolved inorganic carbon in the northwestern Mediterranean deep convection region’

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