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What ocean acidification means for Maine

Ocean acidification is a serious threat to seafood abundance, so much so that the United Nations Environment Program has declared it a threat to international food security. Carbon dioxide is increasing in the atmosphere at shocking rates, which in turn causes an increased amount of carbon in the world’s oceans. More carbon dioxide in oceans causes an increase in oceans’ acidity, contributing to less carbonate available for marine animals who need it to create their shells and skeletons, and overall has the potential for devastating impacts globally. One area where this acidification would be the most detrimental is the Gulf of Maine because of its geographical position and the influx of fresh, cold water into the gulf. According to the Natural Resources Defence Council, Maine is at high risk for economic harm due to ocean acidification because of the ocean acidifying soonest in this area and the fact that residents here rely on shellfish for their livelihoods. Maine’s marine resource economy depends on harvesting shelled animals including lobsters, oysters, urchins, and clams.

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Assessing the remaining carbon budget through the lens of policy-driven acidification and temperature targets

Basing a remaining carbon budget on warming targets is subject to uncertainty due to uncertainty in the relationship between carbon emissions and warming. Framing emissions targets using a warming target therefore may not prevent dangerous change throughout the entire Earth system. Here, we use a climate emulator to constrain a remaining carbon budget that is more representative of the entire Earth system by using a combination of both warming and ocean acidification targets. The warming targets considered are the Paris Agreement targets of 1.5 and 2 °C; the acidification targets are −0.17 and −0.21 pH units, informed by aragonite saturation states where coral growth begins to be compromised. The aim of the dual targets is to prevent not only damage associated with warming, but damage to corals associated with atmospheric carbon and ocean acidification. We find that considering acidification targets in conjunction with warming targets narrows the uncertainty in the remaining carbon budget, especially in situations where the acidification target is more stringent than, or of similar stringency to, the warming target. Considering a strict combination of the two more stringent targets (both targets of 1.5 °C warming and −0.17 acidification must be met), the carbon budget ranges from −74.0 to 129.8PgC. This reduces uncertainty in the carbon budget from by 29% (from 286.2PgC to 203.8PgC). This reduction comes from reducing the high-end estimate of the remaining carbon budget derived from just a warming target. Assuming an emissions rate held constant since 2021 (which is a conservative assumption), the budget towards both targets was either spent by 2019 or will be spent by 2026.

Continue reading ‘Assessing the remaining carbon budget through the lens of policy-driven acidification and temperature targets’

Carbonate Chemistry and the Potential for Acidification in Georgia Coastal Marshes and the South Atlantic Bight, USA

In coastal regions and marginal bodies of water, the increase in partial pressure of carbon dioxide (pCO2) in many instances is greater than that of the open ocean due to terrestrial (river, estuarine, and wetland) influences, decreasing buffering capacity and/or increasing water temperatures. Coastal oceans receive freshwater from rivers and groundwater as well as terrestrial-derived organic matter, both of which have a direct influence on coastal carbonate chemistry. The objective of this research is to determine if coastal marshes in Georgia, USA, may be “hot-spots” for acidification due to enhanced inorganic carbon sources and if there is terrestrial influence on offshore acidification in the South Atlantic Bight (SAB). The results of this study show that dissolved inorganic carbon (DIC) and total alkalinity (TA) are elevated in the marshes compared to predictions from conservative mixing of the freshwater and oceanic end-members, with accompanying pH around 7.2 to 7.6 within the marshes and aragonite saturation states (ΩAr) <1. In the marshes, there is a strong relationship between the terrestrial/estuarine-derived organic and inorganic carbon and acidification. Comparisons of pH, TA, and DIC to terrestrial organic material markers, however, show that there is little influence of terrestrial-derived organic matter on shelf acidification during this period in 2014. In addition, ΩAr increases rapidly offshore, especially in drier months (July). River stream flow during 2014 was anomalously low compared to climatological means; therefore, offshore influences from terrestrial carbon could also be decreased. The SAB shelf may not be strongly influenced by terrestrial inputs to acidification during drier than normal periods; conversely, shelf waters that are well-buffered against acidification may not play a significant role in mitigating acidification within the Georgia marshes.

Continue reading ‘Carbonate Chemistry and the Potential for Acidification in Georgia Coastal Marshes and the South Atlantic Bight, USA’

A decade of marine inorganic carbon chemistry observations in the northern Gulf of Alaska – insights to an environment in transition

As elsewhere in the global ocean, the Gulf of Alaska is experiencing the rapid onset of ocean acidification (OA) driven by oceanic absorption of anthropogenic emissions of carbon dioxide from the atmosphere. In support of OA research and monitoring, we present here a data product of marine inorganic carbon chemistry parameters measured from seawater samples taken during biannual cruises between 2008 and 2017 in the northern Gulf of Alaska. Samples were collected each May and September over the 10–year period using a conductivity, temperature, depth (CTD) profiler coupled with a Niskin bottle rosette at stations including a long–term hydrographic survey transect known as the Gulf of Alaska (GAK) Line. This dataset includes discrete seawater measurements such as dissolved inorganic carbon and total alkalinity, which allows the calculation of other marine carbon parameters, including carbonate mineral saturation states, carbon dioxide (CO2), and pH. Cumulative daily Bakun upwelling indices illustrate the pattern of downwelling in the northern Gulf of Alaska, with a period of relaxation spanning between the May and September cruises. The observed time and space variability impart challenges for disentangling the OA signal despite this dataset spanning a decade. However, this data product greatly enhances our understanding of seasonal and interannual variability on the marine inorganic carbon system parameters. The product can also aid in the ground truthing of biogeochemical models, refining estimates of sea–air CO2 exchange, and determining appropriate CO2 parameter ranges for experiments targeting potentially vulnerable species. Data are available at (Monacci et al., 2023).

Continue reading ‘A decade of marine inorganic carbon chemistry observations in the northern Gulf of Alaska – insights to an environment in transition’

Recruiting Steering Committee members for the GOA-ON regional hub for Pacific Islands & Territories (PI-TOA)

PI-TOA GOA-ON Regional Hub is currently recruiting new steering committee members since four current members’ terms are up at the end of 2023. Steering committee members are elected for three year terms and are expected to fulfill the duties outlined in the PI-TOA Steering Committee Roles and Requirements Document linked below.

All interested ocean professionals within the Pacific Islands and Territories are welcomed to apply and early career ocean professionals are particularly encouraged to submit applications to increase cross collaboration between the early career ICONEC Community and PI-TOA.

To submit an application, please send an email by 6 October 2023 to the GOA-ON Secretariat ( with a statement of interest, explanation of relevant experience, and a CV. Please spread this notice widely and reach out to the GOA-ON Secretariat with any questions.

PI-TOA (Pacific Islands & Territories Ocean Acidification) Network

The term “Toa” means “warrior” in many Polynesian Island languages. The PI-TOA network works collectively to better understand and combat the impacts of ocean acidification in the region. In recent years, there have been several ocean acidification trainings and “GOA-ON in a Box” kit recipients in the Pacific Islands and Territories. As capacity for ocean acidification monitoring increases in the region, there is an increasing need for collaboration and communication among the various islands and territories.

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The benthic-pelagic coupling affects the surface water carbonate system above groundwater-charged coastal sediments

Submarine groundwater discharge (SGD) can be a significant source of dissolved nutrients, inorganic and organic carbon, and trace metals in the ocean and therefore can be a driver for the benthic-pelagic coupling. However, the influence of hypoxic or anoxic SGD on the carbonate system of coastal seawater is still poorly understood. In the present study, the production of dissolved inorganic carbon (DIC) and alkalinity (AT) in coastal sediments has been investigated under the impact of oxygen-deficient SGD and was estimated based on the offset between the measured data and the conservative mixing of the end members. Production of AT and DIC was primarily caused by denitrification and sulphate reduction. The AT and DIC concentrations in SGD decreased by approximately 32% and 37% mainly due to mixing with seawater counterbalanced by reoxidation and CO2 release into the atmosphere. Total SGD-AT and SGD-DIC fluxes ranged from 0.1 to 0.2mol m-2 d-1 and from 0.2 to 0.3mol m-2 d-1, respectively. These fluxes are probably the reason why the seawater in the Bay of Puck is enriched in AT and DIC compared to the open waters of the Baltic Sea. Additionally, SGD had low pH and was undersaturated with respect to the forms of the aragonite and calcite minerals of CaCO3. The seawater of the Bay of Puck also turned out to be undersaturated in summer (Inner Bay) and fall (Outer Bay). We hypoth​e​size that SGD can potentially contribute to ocean acidification and affect the functioning of the calcifying invertebrates.

Continue reading ‘The benthic-pelagic coupling affects the surface water carbonate system above groundwater-charged coastal sediments’

Ocean Protector – understanding ocean and coastal acidification through game-based learning

Engaging for studentsAugmented for educators

Ocean Protector is a free online educational game that teaches students about the impacts of ocean acidification and how they can take action to prevent it.

Through a series of interactive decisions and evaluations, students will learn about the causes and effects of ocean acidification and evaluate solutions that can help reduce its impact on marine ecosystems and people.

This decision-driven experience helps students construct explanations, reason effectively, and become self-directed learners involving marine science and ocean literacy.

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Save the date: Ocean Acidification Week 2023, 30 October – 3 November 2023

OA Week debuted in 2020, and returned in 2021, when events and conferences were postponed due to COVID-19. Following the successful in-person Symposium on the Ocean in a High CO2 World in 2022, GOA-ON is bringing back OA Week 2023 to maintain momentum around OA research and provide a virtual platform for the ocean acidification community to exchange their latest findings. This virtual symposium will bring together researchers across the world with sessions, plenary speakers, and engaging talks about ocean acidification research. If you have specific questions, please contact us at

The key goals of OA Week are:

  • Engage the OA and broader oceanographic communities, raise awareness to the issue of OA, and bring attention to the global OA monitoring, research, capacity building, and education efforts
  • Share GOA-ON’s three high-level goals
  • Raise awareness and create community around OA research to support the UN Ocean Decade Endorsed Programme OARS in its implementation phase
  • Engage early career ocean professionals through ICONEC
Continue reading ‘Save the date: Ocean Acidification Week 2023, 30 October – 3 November 2023’

The estuarine environment and pH variation: natural limits and experimental observation of the acidification effect on phosphorus bioavailability (in Portuguese)

This study shows the variation of pH in the Cananéia-Iguape Estuarine-Lagoon Complex (CIELC). Data from 3 years (2019, 2021, 2022) were obtained in 17 points presenting the following ranges: temperature (14.88-27.05 ºC), pH (7.16-8.40) and DIP (0.20-11.28 µmol L-1) along a saline gradient (0.05-32.09) under different hydrodynamics, biogeochemical processes and anthropogenic influence. The pH buffering capacity due to the presence of weak acid salts in saline water (S ≥ 30) was associated to the lowest DIP, decreasing with low salinity values, confirming the direct correlation among salinity and pH. The highest temperatures in the winter of 2021, corroborated with the abnormal climate event in that year. An in vitro experiment showed results of the interaction of PID and sediments with different textures, with and without the presence of the benthic microbiota under a considerable decreasing of the pH (acidification) in relation to the natural condition of this environment. The P sediment flux characterized Iguape sector as a P sink with or without biota, Ararapira sector as a P source with biota and Cananéia, as P source without biota. The salt water buffered the pH and sediment buffered DIP both associated to the biogeochemical and hydrodynamic processes contribute to the homeostasis in the system.

Continue reading ‘The estuarine environment and pH variation: natural limits and experimental observation of the acidification effect on phosphorus bioavailability (in Portuguese)’

Job opportunity: Research Scientist 2 – Marine Carbon, University of Washington, Seattle, USA

Deadline for applications: 22 September 2023

This employee will be responsible for collecting, analyzing, compiling, distributing and archiving data generated in the laboratory and at sea from discrete and continuous sampling instruments in support of ocean acidification and ocean carbon cycle research conducted by CICOES and the National Oceanic and Atmospheric Administration (NOAA). This CICOES/UW employee will work within the Carbon Dioxide Program at NOAA’s Pacific Marine Environmental Laboratory performing cutting-edge research on anthropogenic impacts on the marine carbon cycle, with a focus on ocean acidification studies.


  • 50% – Assist in collecting and analyzing samples and data in the laboratory through analysis of seawater samples for total alkalinity, dissolved inorganic carbon, and pH using custom-built instruments in laboratory settings following established standard operating procedures and good laboratory practices.
  • 30% – Participate on coastal and open-ocean oceanographic research cruises to collect and analyze seawater samples for alkalinity, dissolved inorganic carbon, and pH, and operate seawater chemistry monitoring instruments for seawater CO2 for periods of time from days to a few months.
  • 10% – Collect, compile, analyze, distribute, and archive data and metadata generated by the PMEL Carbon Dioxide Program.  These data will be collected in traditional formats (e.g., laboratory notebooks and MS Excel).  This researcher will be responsible for quality controlling and managing these data in several digital formats commonly used by collaborators and national data archiving centers.
  • 10% – Other tasks may be assigned as availability allows, including: general laboratory tasks such as chemical inventory management, glassware cleaning, ordering supplies, and maintaining an orderly, clean and safe laboratory space.
  • Assist Carbon Dioxide Program PIs with data analysis and visualization and preparation of text, tables, and statistical analyses for scientific reports, publications, proposals, and presentations.
  • Represent the group at technical meetings related to the employee’s key responsibilities.
Continue reading ‘Job opportunity: Research Scientist 2 – Marine Carbon, University of Washington, Seattle, USA’

SOARCE Webinar Series – A new wave of ocean acidification communication: engaging communities using StoryMaps

Date and time: Wednesday, 13 September 2023, 7:00 PM – 8:00 PM CEST

Location: online

Ocean acidification (OA) is linked to environmental, economic, and societal losses in communities reliant on threatened ecosystems and fisheries. Alaskans are particularly vulnerable compared to lower latitudes, experiencing accelerated OA and higher dependencies on at-risk species for industry and subsistence. However, OA remains under-discussed and often misunderstood by many educators, industry workers, and community members.

To better engage with communities affected by OA, NOAA’s Ocean Acidification Program, the OA Alliance, the Alaska OA Network, and the Aquarium Conservation Partnership collaborated to increase targeted OA communication in Alaska. Together, we created a public-friendly digital StoryMap detailing local impacts of and responses to OA that aquariums or educational centers can implement or promote. Similar StoryMaps are being designed for other regions and aquariums from the West Coast to the Gulf Coast to emphasize aspects of OA across the US. In fact, local aquarium or education center partners are working on increasing local engagement with the StoryMaps through different storytelling, design, and implementation choices.

Continue reading ‘SOARCE Webinar Series – A new wave of ocean acidification communication: engaging communities using StoryMaps’

Ocean acidification reduces iodide production by the marine diatom Chaetoceros sp. (CCMP 1690)


  • Ocean acidification had no effect on growth rates of the diatom Chaetoceros sp. CCMP (1690) but higher cell yield under high CO2.
  • Ocean acidifcation has the potential to inhibit the diatom-mediated iodate to iodide reduction process.
  • Iodide production was decoupled from iodate uptake and refute the proposed link between iodide produced and cell membrane permeability.


Phytoplankton in marine surface waters play a key role in the global iodine cycle. The biologically-mediated iodide production under future scenarios is limited. Here we compare growth, iodate to iodide conversion rate and membrane permeability in the diatom Chaetoceros sp. (CCMP 1690) grown under seawater carbonate chemistry conditions projected for 2100 (1000 ppm) and pre-industrial (280 ppm) conditions. We found no effect of CO2 on growth rates, but a significantly higher cell yield under high CO2, suggesting sustained growth from relief from carbon limitation. Cell normalised iodate uptake (16.73 ± 0.92 amol IO3 cell−1) and iodide production (8.61 ± 0.15 amol I cell−1) was lower in cultures grown at high pCO2 than those exposed to pre-industrial conditions (21.29 ± 2.37 amol IO3 cell−1, 11.91 ± 1.49 amol I cell−1, respectively). Correlating these measurements with membrane permeability, we were able to ascertain that iodide conversion rates were not linked to cell permeability and that the processes of mediated iodate loss and diatom-iodide formation are decoupled. These findings are the first to implicate OA in driving a potential shift in diatom-mediated iodate reduction. If our results are indicative of diatom-mediated iodine cycling in 2100, future surface ocean conditions could experience reduced rates of iodide production by Chaetoceros spp., potentially lowering iodide concentrations in ocean regions dominated by this group. These changes have the potential to impact ozone cycling and new particle formation in the atmosphere.

Continue reading ‘Ocean acidification reduces iodide production by the marine diatom Chaetoceros sp. (CCMP 1690)’

The combined effect of pH and dissolved inorganic carbon concentrations on the physiology of plastidic ciliate Mesodinium rubrum and its cryptophyte prey

Ocean acidification is caused by rising atmospheric partial pressure of CO2 (pCO2) and involves a lowering of pH combined with increased concentrations of CO2 and dissolved in organic carbon in ocean waters. Many studies investigated the consequences of these combined changes on marine phytoplankton, yet only few attempted to separate the effects of decreased pH and increased pCO2. Moreover, studies typically target photoautotrophic phytoplankton, while little is known of plastidic protists that depend on the ingestion of plastids from their prey. Therefore, we studied the separate and interactive effects of pH and DIC levels on the plastidic ciliate Mesodinium rubrum, which is known to form red tides in coastal waters worldwide. Also, we tested the effects on their prey, which typically are cryptophytes belonging to the Teleaulax/Plagioslemis/Geminigera species complex. These cryptophytes not only serve as food for the ciliate, but also as a supplier of chloroplasts and prey nuclei. We exposed M. rubrum and the two cryptophyte species, T. acuta, T. amphioxeia to different pH (6.8 – 8) and DIC levels (∼ 6.5 – 26 mg C L-1) and assessed their growth and photosynthetic rates, and cellular chlorophyll a and elemental contents. Our findings did not show consistent significant effects across the ranges in pH and/or DIC, except for M. rubrum, for which growth was negatively affected only by the lowest pH of 6.8 combined with lower DIC concentrations. It thus seems that M. rubrum is largely resilient to changes in pH and DIC, and its blooms may not be strongly impacted by the changes in ocean carbonate chemistry projected for the end of the 21th century.

Continue reading ‘The combined effect of pH and dissolved inorganic carbon concentrations on the physiology of plastidic ciliate Mesodinium rubrum and its cryptophyte prey’

New research tool depicts ocean acidification in colored stripes

Most people consider climate change to consist only of the warming of the atmosphere, the consequences of which primarily affect land regions. However, this is a human-centered view and does not go far enough.

This view overlooks the fact that the oceans are also strongly affected by climate change. Not only do they absorb a large part of the extra heat that the increased concentration of greenhouse gases generate in the atmosphere, they also absorb about one-third of manmade CO2 emissions from the atmosphere. This CO2 uptake causes the oceans to acidify—with significant consequences for marine life.

“Despite these profound changes, many people are not aware of what is happening to our oceans,” says Nicolas Gruber, Professor of Environmental Physics at ETH Zurich. The marine researcher and his team want to change that.

But how can people understand such an abstract concept for a complex process in an unfamiliar habitat?

Continue reading ‘New research tool depicts ocean acidification in colored stripes’

Hidden ocean acidification threatens the Pacific. Now there’s a plan to stop ‘flying blind’

For generations, the people of Fiji have built their lives around the country’s rich coral reef ecosystems. The ocean provides sustenance, while the dazzling marine life brings tourists from around the world. But climate change is threatening this way of life. Sea level rise is forcing coastal villages to relocate, with many more in peril. More frequent natural disasters have taken lives and destroyed houses, crops and infrastructure. But there’s another effect of climate change that isn’t as easy to see — an insidious rising danger for the people of Fiji: ocean acidification.

“When it hits, it’s going to be catastrophic,” says Katy Soapi, coordinator of the Pacific Community Centre for Ocean Science at the science and development organisation SPC. Worse still, Dr Soapi says Fiji and the broader Pacific region aren’t watching the emerging threat closely enough. “We are definitely flying blind,” she says. Many Pacific Island nations have historically lacked the resources to monitor the scale of the problem in their own waters. But now Dr Soapi is helping to establish a network of scientists that will use novel methods to turn this around.

Continue reading ‘Hidden ocean acidification threatens the Pacific. Now there’s a plan to stop ‘flying blind’’

Predicting the impacts of climate change on New Zealand’s seaweed-based ecosystems

The impacts of global climate change are threatening the health and integrity of New Zealand’s seaweed ecosystems that provide crucial ecological, economic, and cultural benefits. Important species that comprise these ecosystems include canopy forming large brown algae (fucoids and kelp), and understorey species. Here we review current knowledge of the measured impacts of climate change stressors on New Zealand seaweeds. Ocean warming has driven increasing frequencies, durations, and intensities of marine heatwaves globally and in New Zealand. Significant negative impacts resulting from heatwaves have already been observed on New Zealand’s canopy forming brown algae (giant kelp Macrocystis pyrifera and bull kelp Durvillaea spp.). We predict that ongoing ocean warming and associated marine heatwaves will alter the distributional range and basic physiology of many seaweed species, with poleward range shifts for many species. Increased extreme weather events causes accelerated erosion of sediments into the marine environment and re-suspension of these sediments, termed coastal darkening, which has reduced the growth rates and available vertical space on rocky reefs in New Zealand and is predicted to worsen in the future. Furthermore, ocean acidification will reduce the growth and recruitment of coralline algae, this may reduce the settlement success of many marine invertebrate larvae. Mechanistic underpinnings of the effects of multiple drivers occurring in combination is poorly described. Finally, local stressors, such as overfishing, will likely interact with global change in these ecosystems. Thus, we predict very different futures for New Zealand seaweed ecosystems depending on whether they are managed appropriately or not. Given recent increases in sea surface temperatures and the increasing frequency of extreme weather events in some regions of New Zealand, predicting the impacts of climate change on seaweeds and the important communities they support is becoming increasingly important for conserving resilient seaweed ecosystems in the future.

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Study of estuaries finds lower acidification than in oceans

A study of the country’s two largest estuaries reveals that inshore coastal waters are not necessarily experiencing what scientists say is a worrisome global trend of increasingly acidic oceans.

The recently published paper is the latest in a small collection of studies highlighting the complexities of coastal zones onshore.

In this case, researchers looked at trends from data collected more than 20 years within the Neuse River Estuary-Pamlico Sound waters and Chesapeake Bay and found that things like nutrient pollution and algal blooms play a role in how carbon dioxide is dissolved in inland coastal waters.

Research Assistant Professor Nathan Hall with the University of North Carolina Chapel Hill Institute of Marine Sciences in Morehead City and co-author of the study explained that eutrophication is effectively causing, in some cases, estuarine waters to have lower acidification than that of the ocean.

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Simultaneous warming and acidification limit population fitness and reveal phenotype costs for a marine copepod

Phenotypic plasticity and evolutionary adaptation allow populations to cope with global change, but limits and costs to adaptation under multiple stressors are insufficiently understood. We reared a foundational copepod species, Acartia hudsonica, under ambient (AM), ocean warming (OW), ocean acidification (OA), and combined ocean warming and acidification (OWA) conditions for 11 generations (approx. 1 year) and measured population fitness (net reproductive rate) derived from six life-history traits (egg production, hatching success, survival, development time, body size and sex ratio). Copepods under OW and OWA exhibited an initial approximately 40% fitness decline relative to AM, but fully recovered within four generations, consistent with an adaptive response and demonstrating synergy between stressors. At generation 11, however, fitness was approximately 24% lower for OWA compared with the AM lineage, consistent with the cost of producing OWA-adapted phenotypes. Fitness of the OWA lineage was not affected by reversal to AM or low food environments, indicating sustained phenotypic plasticity. These results mimic those of a congener, Acartia tonsa, while additionally suggesting that synergistic effects of simultaneous stressors exert costs that limit fitness recovery but can sustain plasticity. Thus, even when closely related species experience similar stressors, species-specific costs shape their unique adaptive responses.

Continue reading ‘Simultaneous warming and acidification limit population fitness and reveal phenotype costs for a marine copepod’

Physiological and ecological tipping points caused by ocean acidification

Ocean acidification is predicted to cause profound shifts in many marine ecosystems by impairing the ability of calcareous taxa to calcify and grow, and by influencing the photo-physiology of many others. In both calcifying and non-calcifying taxa, ocean acidification could further impair the ability of marine life to regulate internal pH, and thus metabolic function and/or behaviour. Identifying tipping points at which these effects will occur for different taxa due to the direct impacts of ocean acidification on organism physiology is difficult and they have not adequately been determined for most taxa, nor for ecosystems at higher levels. This is due to the presence of both resistant and sensitive species within most taxa. However, calcifying taxa such as coralline algae, corals, molluscs, and sea urchins appear to be most sensitive to ocean acidification. Conversely, non-calcareous seaweeds, seagrasses, diatoms, cephalopods, and fish tend to be more resistant, or even benefit from the direct effects of ocean acidification. While physiological tipping points of the effects of ocean acidification either do not exist or are not well defined, their direct effects on organism physiology will have flow on indirect effects. These indirect effects will cause ecologically tipping points in the future through changes in competition, herbivory and predation. Evidence for indirect effects and ecological change is mostly taken from benthic ecosystems in warm temperate–tropical locations in situ that have elevated CO2. Species abundances at these locations indicate a shift away from calcifying taxa and towards non-calcareous at high CO2 concentrations. For example, lower abundance of corals and coralline algae, and higher covers of non-calcareous macroalgae, often turfing species, at elevated CO2. However, there are some locations where only minor changes, or no detectable change occurs. Where ecological tipping points do occur, it is usually at locations with naturally elevated pCO2 concentrations of 500 μatm or more, which also corresponds to just under that concentrations where the direct physiological impacts of ocean acidification are detectable on the most sensitive taxa in laboratory research (coralline algae and corals). Collectively, the available data support the concern that ocean acidification will most likely cause ecological change in the near future in most benthic marine ecosystems, with tipping points in some ecosystems at as low as 500 μatm pCO2. However, much more further research is required to more adequately quantify and model the extent of these impacts in order to accurately project future marine ecosystem tipping points under ocean acidification.

Continue reading ‘Physiological and ecological tipping points caused by ocean acidification’

Deadline approaching – Ocean Sciences Meeting 2024 session: Advancing ocean acidification forecasts and projections: the need for better representation of coastal processes and biology

Deadline for abstract submission: 13 September 2023

While the increase of atmospheric CO2 from fossil fuel burning is the main driver of ocean acidification (OA), coastal processes (e.g., upwelling, river input, benthic production and respiration) can increase complexity. Local coastal processes can modulate or exacerbate OA from atmospheric CO2, and these processes occur on spatial scales that are not well represented in global climate models (GCMs). Additionally, projections rely mainly on chemical-physical variables with simplistic thresholds for the status and trends of biodiversity and ecosystem services. As a result, predictive information to support decisions facing coastal communities on OA impacts is largely lacking.

Ocean predictions and projections on local scales to support decisions require us to employ new technologies: digital twins, machine learning, high resolution predictions, observational data utilization, and integration of biological and ecological information.  

This session highlights best practices for forecasting and providing localized projections, new approaches to address the computationally intense requirements of providing climate information at hyper-local scales, advancing the integration of biological and ecological information, innovative technologies that integrate autonomous real time observations and visualization of the output. We invite all approaches that deliver forecasts, projections of state, variability, phenology as well as novel ways of delivering data/knowledge to stakeholders.

Continue reading ‘Deadline approaching – Ocean Sciences Meeting 2024 session: Advancing ocean acidification forecasts and projections: the need for better representation of coastal processes and biology’

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