This aquatic grass could help shellfish threatened by ocean acidification (video)

An increase in carbon emissions are showing up not only in the air, but also in water. Now researchers and shellfish farmers are teaming up to see how marine plants can help stave off the effects of ocean acidification. Special correspondent Jes Burns of Oregon Public Broadcasting reports.

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Nitrogen availability modulates the effects of ocean acidification on biomass yield and food quality of a marine crop Pyropia yezoensis


• Higher pCO2 reduces growth of Pyropia yezoensis.
• Higher pCO2 induces synthesis of phycobiliprotein and flavor amino acids.
• Higher nitrate alleviates the negative effect of ocean acidification on growth.
• Higher nitrate and pCO2 synergistically stimulate phycobiliprotein synthesis.
• Higher nitrate and higher pCO2 synergistically stimulate amino acid synthesis.


Pyropia yezoensis is an important marine crop in the world. We cultured it under two levels of partial pressure of carbon dioxide (pCO2) (408 (LC), 998 (HC) μatm) and nitrate (30 (LN) and 500 (HN) μmol L-1) to investigate the effect of ocean acidification on its growth and food quality under changing nitrogen supply. HC decreased growth rate of P. yezoensis under LN but did not affect it under HN. Phycoerythrin and phycocyanin were enhanced by HC, particularly at HN, which contributed to the darker color. HC stimulated the synthesis of sweat amino acids regardless of nitrate condition and umami amino acid only under LN. HN increased the content of umami amino acids regardless of pCO2 condition and sweet amino acids only under LC. Our findings indicate that future ocean acidification may reduce biomass yield of P. yezoensis but increase its color and flavor, which was regulated by nitrate availability.

Continue reading ‘Nitrogen availability modulates the effects of ocean acidification on biomass yield and food quality of a marine crop Pyropia yezoensis’

Ocean acidification alters morphology of all otolith types in Clark’s anemonefish (Amphiprion clarkii)

Ocean acidification, the ongoing decline of surface ocean pH and [CO32-] due to absorption of surplus atmospheric CO2, has far-reaching consequences for marine biota, especially calcifiers. Among these are teleost fishes, which internally calcify otoliths, critical elements of the inner ear and vestibular system. There is evidence in the literature that ocean acidification increases otolith size and alters shape, perhaps impacting otic mechanics and thus sensory perception. However, existing analyses of otolith morphological responses to ocean acidification are limited to 2-dimensional morphometrics and shape analysis. Here, we reared larval Clark’s anemonefish, Amphiprion clarkii (Bennett, 1830), in various seawater pH treatments analogous to future ocean scenarios in a 3x-replicated experimental design. Upon settlement, we removed all otoliths from each individual fish and analyzed them for treatment effects on morphometrics including area, perimeter, and circularity; further, we used scanning electron microscopy to screen otoliths visually for evidence of treatment effects on lateral development, surface roughness, and vaterite replacement. Our results corroborate those of other experiments with other taxa that observed otolith growth with elevated pCO2, and provide evidence that lateral development and surface roughness increased as well; we observed at least one of these effects in all otolith types. Finally, we review previous work investigating ocean acidification impacts on otolith morphology and hypotheses concerning function, placing our observations in context. These impacts may have consequences teleost fitness in the near-future ocean.

Continue reading ‘Ocean acidification alters morphology of all otolith types in Clark’s anemonefish (Amphiprion clarkii)’

Version 6 of the Surface Ocean CO2 Atlas (SOCAT) now available

More than than 100 contributing scientists worldwide have contributed to Version 6 of the Surface Ocean CO2 Atlas (SOCAT). SOCAT ( is a synthesis activity by international marine carbon scientists with annual public releases. SOCAT version 6 has 23.4 million quality-controlled in situ surface ocean fCO2 (fugacity of carbon dioxide) measurements from 1957 to 2017 for the global oceans and coastal seas, as well as additional calibrated sensor fCO2 measurements.

Continue reading ‘Version 6 of the Surface Ocean CO2 Atlas (SOCAT) now available’

Comparing model parameterizations of the biophysical impacts of ocean acidification to identify limitations and uncertainties


• We explored model approaches for ocean acidification effects on marine organisms.
• Modelled effects on aerobic performance were scaled up to population level dynamics.
• Results were sensitive to model structure, then scenario and parameter uncertainty.
• Sensitivity was variable across species and the source of uncertainty.
• Integrated global change models progress development of future scenarios.


Ocean acidification (OA) driven by anthropogenic CO2 emissions affects marine ecosystems, fisheries and aquaculture. Assessing the impacts of OA using projection models facilitates the development of future scenarios and potential solutions. Here, we explored various ways to incorporate OA impacts into a multi-stressor dynamic bioclimatic envelope model to project biogeographic changes of ten commercially exploited invertebrate species. We examine three dimensions of uncertainties in modelling biophysical OA effects: model structure, parameterization, and scenario uncertainty. Our results show that projected OA impacts are most sensitive to the choice of structural relationship between OA and biological responses, followed by the choice of climate change emission scenarios and parameterizations of the size of OA effects. Species generally showed negative effects to OA but sensitivity to the various sources of uncertainty were not consistent across or within species. For example, some species showed higher sensitivity to structural uncertainty and very low sensitivity to parameter uncertainty, while others showed greatest sensitivity to parameter uncertainty. This variability is largely due to geographic variability and difference in life history traits used to parameterize model simulations. Our model highlights the variability across the sources of uncertainty and contributes to the development of integrating OA impacts in species distribution models. We further stress the importance of defining the limitations and assumptions, as well as exploring the range of uncertainties associated with modelling OA impacts.

Continue reading ‘Comparing model parameterizations of the biophysical impacts of ocean acidification to identify limitations and uncertainties’

Seeking creative solutions to ocean acidification

Paul Williams, Shellfish Management Policy Advisor for the Suquamish Tribe in Washington State, discusses the impacts of ocean acidification in the Pacific Northwest and the challenges for future generations.

“About 10 years ago, I read that we’ve altered the fundamental chemistry of the ocean by making it more acidic. Shellfish have calcium in their shells and acid dissolves calcium. You could see the writing on the wall with some species and that was very, very scary, that realization.” Paul Williams, the Shellfish Management Policy Advisor for the Suquamish Tribe, has been tracking the impact of ocean acidification for years. Despite these alarming red flags, Paul says this realization did not discourage him and he continues to seek ways to mitigate the impacts of changing ocean chemistry. Ocean acidification represents an urgent concern to the Suquamish Tribe, because harvesting shellfish is a traditional practice of tribal members, a key source of income and a way for them to stay connected to their culture.

Continue reading ‘Seeking creative solutions to ocean acidification’

Seasonal variability of carbonate chemistry and decadal changes in waters of a marine sanctuary in the Northwestern Gulf of Mexico


• Temperature dominated seawater carbonate system variations in FGBNMS.
• Subsurface acidification is caused by anthropogenic CO2 uptake and higher respiration.
• The FGBNMS is currently a negligible atmospheric CO2 sink.


We report seasonal water column carbonate chemistry data collected over a three-year period (late 2013 to 2016) at Flower Garden Banks National Marine Sanctuary (FGBNMS) located on the subtropical shelf edge of the northwestern Gulf of Mexico. The FGBNMS hosts the northernmost tropical coral species in the contiguous United States, with over 50% living coral cover. Presented here are results from samples of the upper 25 m of the water column collected from September 2013 to November 2016. Additionally, following a localized mortality event likely associated with major continental flooding in summer 2016, water samples from up to ~250 m depth were collected in the broader FGBNMS area on a rapid response cruise to examine the seawater carbonate system. Both surface (<5 m) total alkalinity (TA) and total dissolved inorganic carbon (DIC) vary over small ranges (2391 ± 19 μmol kg−1 and 2060 ± 19 μmol kg−1, respectively) for all times-series samples. Temperature and salinity both played an important role in controlling the surface water carbonate system dynamics, although temperature was the sole significant factor when there was no flooding. The FGBNMS area acted as a sink for atmospheric CO2 in winter and a CO2 source in summer, while the time-integrated CO2 flux is close to zero (−0.14 ± 1.96 mmol-C m−2 yr−1). Results from three cruises, i.e., the Gulf of Mexico and East Coast Carbon Project (GOMECC-1) in 2007, the rapid response study, and the Gulf of Mexico Ecosystems and Carbon Cruise (GOMECC-3), revealed decreases in both pH and saturation state with respect to aragonitearag) in subsurface waters (~100–250 m) over time. These decreases are larger than those observed in other tropical and subtropical waters. Based on reaction stoichiometry, calculated anthropogenic CO2 contributed 30–41% of the overall DIC increase, while elevated respiration accounted for the rest.

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Ocean acidification in the IPCC AR5 WG II

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