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Continue reading ‘Projet EPOCA : Final Meeting – Acidification des océans (video, in French)’
Archive for April, 2012
Projet EPOCA : Final Meeting – Acidification des océans (video, in French)
Published 10 April 2012 Media coverage ClosedTerms such as ‘red tide’ and ‘global warming’ are catchy but lead to misconceptions.
Words matter. Take the term “red tide,” which is the popularized way of talking about blooms of harmful marine algae. This common terminology is a misnomer because the blooms are not always red and their movement is largely unrelated to tides. Also, many species of algae that cause red discoloration are not harmful.
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A relatively new issue catching public attention is “ocean acidification.” “Ocean acidification” is a term used to describe changes in seawater chemistry due to increasing amounts of CO2 being taken up by the ocean. When CO2 from the atmosphere dissolves into seawater, a series of chemical reactions occurs that effectively lower seawater pH. But while ocean pH is definitely decreasing, the ocean is not actually becoming acidic — just less basic. The world’s oceans are not predicted to drop below a pH of 7.0 (neutral on the pH scale).
We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N2O) to estimate the concentration of biologically produced N2O and N2O production rates in the ocean on a global scale. Our approach to estimate the N2O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N2O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N2O are not taken into account in our study. The largest amount of subsurface N2O is produced in the upper 500 m of the water column. The estimated global annual subsurface N2O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr−1. This is in agreement with estimates of the global N2O emissions to the atmosphere and indicates that a N2O source in the mixed layer is unlikely. The potential future development of the oceanic N2O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed.
Continue reading ‘Global oceanic production of nitrous oxide’
Acidification and warming affect both a calcifying predator and prey, but not their interaction
Published 6 April 2012 Science ClosedTags: Baltic, biological response, crustaceans, mollusks, morphology, performance
Both ocean warming and acidification have been demonstrated to affect the growth, performance and reproductive success of calcifying invertebrates. However, relatively little is known regarding how such environmental change may affect interspecific interactions. We separately treated green crabs Carcinus maenas and periwinkles Littorina littorea under conditions that mimicked either ambient conditions (control) or warming and acidification, both separately and in combination, for 5 mo. After 5 mo, the predators, prey and predator-prey interactions were screened for changes in response to environmental change. Acidification negatively affected the closer-muscle length of the crusher chela and correspondingly the claw-strength increment in C. maenas. The effects of warming and/or acidification on L. littorea were less consistent but indicated weaker shells in response to acidification. On the community level, however, we found no evidence that predator-prey interactions will change in the future. Further experiments exploring the impacts of warming and acidification on key ecological interactions are needed instead of basing predictions of ecosystem change solely on species-specific responses to environmental change.
Carbonate production by calcareous red algae and global change
Published 6 April 2012 Science ClosedTags: biological response, calcification, corals, review
The most important groups of modern red calcareous algae are the Mg-calcite secreting Corallinales and Sporolithales, and the aragonitic Peyssonneliales and Nemaliales. They are common on the world’s shelves and are vulnerable to the global warming and the lowering of pH of sea water, caused by the ongoing increase in anthropogenic CO2. Among them, coralline algae are ecosystem engineers and major producers of carbonate sediment, of particular importance in temperate and cold seas. Corallines respond to marine acidification and rising temperature showing decreased net calcification, decreased growth and reproduction, as well as reduced abundance and diversity, leading to death and ecological shift to dominant non-calcifying algae. Despite their key ecological and sedimentological role, and because of their vulnerability to marine warming and acidification, our knowledge of the distribution of coralline-dominated habitats and the quantification of their carbonate production is not adequate to allow proper environmental management and confident modelling of a global carbon budget. Locating the algal carbonate factories around the world, then describing them, e.g., evaluating their extent and their production, are a priority for future research.
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New ocean acidification sensor installed at Scripps!
Published 6 April 2012 Science , Web sites and blogs ClosedOn Tuesday, March 13th 2012, members of the Smith Lab and the Scripps Diving Safety Office excitedly directed SCUBA divers (Andi Haas and Brian Zgliczynski) as they permanently installed Scripps’ first ocean acidification monitoring system. The monitoring system is attached underwater to a Scripps pier piling and will record seawater pH, salinity, temperature, oxygen and chlorophyll a every 15 minutes for the foreseeable future. The sensor package (engineered at Scripps), will be recovered and downloaded every month by volunteer Scripps divers. A collaborative team of ocean acidification researchers, led by Drs. Jennifer Smith and Nichole Price, will use this data to monitor local changes in ocean chemistry over time.
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Coastal acidification in summer bottom oxygen-depleted waters in northwestern-northern Bohai Sea from June to August in 2011
Published 6 April 2012 Science ClosedTags: chemistry, field, modeling, North Pacific
Dissolved oxygen (DO) and pH in the central part of the Bohai Sea were surveyed in late June and late August, 2011. During the June cruise, the bottom DO was in the range of 215–290 μmol-O2 kg−1 (i.e. 85%–115% of the saturation level), and the bottom pH was in the range of 7.82–8.04 on the total-hydrogen-ion scale. In August, however, both the bottom DO and the pH had significantly declined in the northwestern-northern near-shore areas, where the water depth was no more than 35 m. The lowest bottom DO was 100–110 μmol-O2 kg−1 (only 44%–47% of the June DO values) in the northern near-shore area, where the bottom pH was 7.64–7.68 on the total-hydrogen-ion scale (0.16–0.20 units lower than the June pH value). The largest decreases in DO and in pH were observed in the northwestern near-shore bottom waters, corresponding to declines of 170 μmol-O2 kg−1 (as high as 59% of the June DO value) and 0.29 pH units, respectively. The greatest pH decline of 0.29 pH units meant that the total-hydrogen-ion concentration doubled in the bottom waters from June to August. Based on field measurements of bottom DO/pH combined with a simplified model simulation, we suggest that respiration/remineralization-derived CO2 increased the acidity in the bottom oxygen-depleted waters of northwestern-northern near-shore areas in the Bohai Sea as a result of coastal red tides and/or marine aquaculture. This aquatic chemistry is suggested to be partially responsible for scallop-breeding failures in the northwestern Bohai Sea in summer 2011.
Corals may be better placed to cope with the gradual acidification of the world’s oceans than previously thought — giving rise to hopes that coral reefs might escape climatic devastation.
In new research published in the journal Nature Climate Change, an international scientific team has identified a powerful internal mechanism that could enable some corals and their symbiotic algae to counter the adverse impact of a more acidic ocean.
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Coral resilience to ocean acidification and global warming through pH up-regulation
Published 6 April 2012 Science ClosedTags: biological response, calcification, corals, laboratory
Rapidly rising levels of atmospheric CO2 are not only causing ocean warming, but also lowering seawater pH hence the carbonate saturation state of the oceans, on which many marine organisms depend to calcify their skeletons. Using boron isotope systematics, we show how scleractinian corals up-regulate pH at their site of calcification such that internal changes are approximately one-half of those in ambient seawater. This species-dependent pH-buffering capacity enables aragonitic corals to raise the saturation state of their calcifying medium, thereby increasing calcification rates at little additional energy cost. Using a model of pH regulation combined with abiotic calcification, we show that the enhanced kinetics of calcification owing to higher temperatures has the potential to counter the effects of ocean acidification. Up-regulation of pH, however, is not ubiquitous among calcifying organisms; those lacking this ability are likely to undergo severe declines in calcification as CO2 levels increase. The capacity to up-regulate pH is thus central to the resilience of calcifiers to ocean acidification, although the fate of zooxanthellate corals ultimately depends on the ability of both the photosymbionts and coral host to adapt to rapidly increasing ocean temperatures.
Impact of exposure to elevated pCO2 on the physiology and behaviour of an important ecosystem engineer, the burrowing shrimp Upogebia deltaura
Published 5 April 2012 Science ClosedTags: biological response, crustaceans
There is an increasing need to predict the effects of global climate change on ecologically important marine organisms and a demand for proactive solutions to reduce CO2 emissions. CO2 sequestration is one such method. While this offers a practical solution, recognition should be given to the potential for considerable localised effects on marine organisms in the event of leakage. This laboratory study quantifies the impact of exposure to elevated pCO2 conditions on the physiological and behavioural responses of a relatively tolerant marine organism. Burrowing shrimps Upogebia deltaura were exposed to CO2-enriched seawater for 35 d to treatments of 1396 µatm (pH 7.64), 2707 µatm (pH 7.35) and 14110 µatm (pH 6.71). CO2 levels represented scenarios which included coastal ocean acidification and extremely elevated CO2 associated with geological CO2 sequestration leaks. Results were compared with those from shrimps maintained in a control treatment (pH 7.99). U. deltaura appeared to be tolerant to elevated pCO2 predicted to occur in the year 2100 (1396 µatm, pH 7.64). However, at 2707 µatm (pH 7.35) shrimps experienced extracellular acidosis, but no difference in haemolymph bicarbonate concentration, suggesting they have little or no buffering capacity, although there was no evidence of other physiological costs in terms of metabolism, osmotic regulation, shell mineralogy, growth and overall activity. At pH 6.71, before 100% mortality occurred, significant differences in activity were observed compared with shrimps in other pH treatments. Results suggest deleterious consequences for benthic ecosystems in the event of a CO2 sequestration leakage.
NOAA/Pacific marine environmental laboratory, oceanographer position
Published 5 April 2012 Jobs ClosedPlease find information below on a position listed at NOAA’s Pacific Marine Environmental Laboratory in Seattle, Washington. The job is open to receive applications from April 3rd to April 16th. The job listing can be found in the April 3rd issue of Eos on page 148, and on the USAJOBS web site. You can only apply for the job through the USAJOBS web site by following the instructions and links below. For further information, I have excerpted the first sentence of the Eos ad here:
“NOAA/Pacific Marine Environmental Laboratory, Oceanographer Position, GS-14/GS-15. The Ocean Climate Research Division of NOAA’s Pacific Marine Environmental Laboratory (PMEL), Seattle, WA, is seeking a highly qualified research scientist and principal investigator with extensive knowledge and experience in systematic research of sources and sinks for anthropogenic carbon dioxide and acidification processes in the oceans.”
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Effects of seawater acidification on cell cycle control mechanisms in Strongylocentrotus purpuratus embryos
Published 4 April 2012 Science ClosedTags: biological response, echinoderms
Previous studies have shown fertilization and development of marine species can be significantly inhibited when the pH of sea water is artificially lowered. Little mechanistic understanding of these effects exists to date, but previous work has linked developmental inhibition to reduced cleavage rates in embryos. To explore this further, we tested whether common cell cycle checkpoints were involved using three cellular biomarkers of cell cycle progression: (1) the onset of DNA synthesis, (2) production of a mitotic regulator, cyclin B, and (3) formation of the mitotic spindle. We grew embryos of the purple sea urchin, Strongylocentrotus purpuratus, in seawater artifically buffered to a pH of ~7.0, 7.5, and 8.0 by CO2 infusion. Our results suggest the reduced rates of mitotic cleavage are likely unrelated to common cell cycle checkpoints. We found no significant differences in the three biomarkers assessed between pH treatments, indicating the embryos progress through the G1/S, G2/M and metaphase/anaphase transitions at relatively similar rates. These data suggest low pH environments may not impact developmental programs directly, but may act through secondary mechanisms such as cellular energetics.
First evidence of immunomodulation in bivalves under seawater acidification and increased temperature
Published 4 April 2012 Science ClosedTags: biological response, mollusks
Water acidification, temperature increases and changes in seawater salinity are predicted to occur in the near future. In such a global climate change (GCC) scenario, there is growing concern for the health status of both wild and farmed organisms. Bivalve molluscs, an important component of coastal marine ecosystems, are at risk. At the immunological level, the ability of an organism to maintain its immunosurveillance unaltered under adverse environmental conditions may enhance its survival capability. To our knowledge, only a few studies have investigated the effects of changing environmental parameters (as predicted in a GCC scenario) on the immune responses of bivalves. In the present study, the effects of both decreased pH values and increased temperature on the important immune parameters of two bivalve species were evaluated for the first time. The clam Chamelea gallina and the mussel Mytilus galloprovincialis, widespread along the coast of the Northwestern Adriatic Sea, were chosen as model organisms. Bivalves were exposed for 7 days to three pH values (8.1, 7.7 and 7.4) at two temperatures (22 and 28°C). Three independent experiments were carried out at salinities of 28, 34 and 40 PSU. The total haemocyte count, Neutral Red uptake, haemolymph lysozyme activity and total protein levels were measured. The results obtained demonstrated that tested experimental conditions affected significantly most of the immune parameters measured in bivalves, even if the variation pattern of haemocyte responses was not always linear. Between the two species, C. gallina appeared more vulnerable to changing pH and temperature than M. galloprovincialis. Overall, this study demonstrated that climate changes can strongly affect haemocyte functionality in bivalves. However, further studies are needed to clarify better the mechanisms of action of changing environmental parameters, both individually and in combination, on bivalve haemocytes.
Why ocean acidification matters to California, and what California can do about it: A report on the power of California’s State Government to address ocean acidification in state waters
Published 4 April 2012 Newsletters and reports ClosedCalifornia’s ocean is becoming more acidic as a result of increased atmospheric carbon dioxide (CO2) and other pollutants. This fundamental change is likely to have substantial ecological and economic consequences for California and worldwide.
This document is intended to be a toolbox for understanding and addressing the drivers of an acidifying ocean. We first provide an overview of the relevant science, highlighting known causes of chemical change in the coastal ocean. We then feature a wide variety of legal and policy tools that California’s government agencies can use to mitigate the problem.
The State has ample legal authority to address the causes of ocean acidification; what remains is to implement that authority to safeguard California’s iconic coastal resources.
Gov. Gregoire convenes panel to study ocean acidification
Published 4 April 2012 Newsletters and reports ClosedGov. Chris Gregoire today announced she has asked Bill Ruckelshaus and Jay Manning to lead a blue ribbon panel of science and policy experts to focus on the emerging problem of ocean acidification that threatens shellfish in the Pacific Northwest.
Washington’s shellfish growers are seeing an increase in the deaths of juvenile shellfish larvae, which has been linked to acidic marine waters. When saltwater becomes acidic, it harms the shell-making ability of oysters, clams, scallops and mussels. It also harms other marine organisms.
Ocean acidification occurs as oceans accumulate carbon dioxide from the atmosphere, from polluted land runoff and other sources.
The panel is the first of its kind in the nation, and will convene for its first meeting tomorrow in Seattle.
“Washington state has a large stake in addressing ocean acidification,” Gregoire said. “Our shellfish industry employs thousands of people, and brings in millions of dollars to our state on an annual basis. Continued success depends on healthy ocean water. Bill Ruckelshaus, Jay Manning and the other panel members will help find ways to respond to ocean acidification to protect both our economy and our natural resources, and I thank them for their willingness to lead this critical effort.”
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Mintz Levin Cohn Ferris Glovsky and Popeo PC
David Leiter, Sarah Litke and Daniel Phillips
House Energy and Commerce Ranking Member Henry Waxman (D-CA) and Energy and Power Subcommittee Ranking Member Bobby Rush (D-IL) sent a letter March 21 to chairmen Fred Upton (R-MI) and Ed Whitfield (R-KY) asking that the committee hold a hearing on a March 2 Science article showing that CO2 deposition is causing oceans to acidify more rapidly than previously thought. Continue reading ‘Ocean acidification’
New report reveals concern, insecurity regarding ocean acidification among Alaska fishermen and coastal residents
Published 4 April 2012 Media coverage ClosedA report released this week by a community-based fisheries group shows concern over the long-term impacts of ocean acidification on Alaska fisheries and livelihoods. The study by the Alaska Marine Conservation Council (AMCC) is based on community roundtable discussions held this winter in the fisheries-dependent communities of Homer, Kodiak, and Dillingham.
“Ocean acidification has the potential to significantly impact the health and productivity of Alaska’s oceans,” said Rachel Donkersloot, lead author of the study and Fisheries Program Director at AMCC. “While we don’t yet know exactly how ocean acidification will affect specific fisheries, we do know it’s a threat to marine habitat and the ocean food web which our economies and communities ultimately depend on. Fishermen and coastal Alaskans are concerned.”
Fish harvesters want role in monitoring of ocean acidity
Published 4 April 2012 Media coverage ClosedA new conservation report culled from community discussions in Kodiak, Dillingham and Homer underscores concern for the health and productivity of oceans coastal communities depend on in the face of rising ocean acidification.
“The economic value of Alaska’s commercial fisheries approaches $4 billion (first wholesale value), but it is not known how ocean acidification will affect specific fisheries and what the cost will be to the seafood industry and fishery-dependent communities,” said report’s author, Rachel Donkersloot, fisheries program director for the Alaska Marine Conservation Council.
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Ocean acidification and Alaska fisheries: Views and voices of Alaska’s fishermen, marine industries and coastal residents
Published 4 April 2012 Newsletters and reports ClosedIn winter 2011-2012 the Alaska Marine Conservation Council (AMCC) sponsored community roundtable discussions on ocean acidification and Alaska fisheries in the fisheries-dependent communities of Homer, Kodiak and Dillingham in southern Alaska.
The roundtables were designed to engage coastal Alaskans and members of the Alaska seafood industry whose lives and local economies will be affected by changes linked to ocean acidification (OA). Specifically, the roundtables were intended to accomplish three inter-related goals: 1) bring together the efforts and expertise of scientists, subsistence harvesters, commercial fishermen, natural resources managers and coastal residents to better assess and address the impacts of OA on local fisheries and livelihoods; 2) develop ideas and advance dialogue concerning the needs and potential contributions of fishermen and fishing communities in responding to the threat posed by OA; and 3) provide insight into how the fishing industry might engage in policy action related to OA in the future.
Increasing acidity of seawater in Hood Canal and along the Washington Coast may be killing off the larval form of shellfish like nowhere else in the world, according to researchers studying the problem.
Such findings — with alarming implications for the shellfish industry — were the impetus for Gov. Chris Gregoire to convene a blue-ribbon panel of 25 scientists, shellfish growers and political leaders, who will examine the latest studies and make recommendations by Oct. 1.
The panel, headed by Bill Ruckelshaus and Jay Manning, was scheduled to hold its first meeting in Seattle on Friday. The agenda includes a review of the latest scientific findings and approval of a schedule for six upcoming meetings. This panel is the first in the United States to focus on regional problems related to ocean acidification, officials say.
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