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Study finds that ocean acidification is accelerated in nutrient-rich areas

Published 25 September 2012 Newsletters and reports , Science Closed

Marine resources, coastal economies put at risk

September 24, 2012

Carbon dioxide released from decaying algal blooms, combined with ongoing increases in atmospheric carbon emissions, leads to increased levels of ocean acidification, and places additional stress on marine resources and the coastal economies that depend on them, according to a new study published today.

Ocean acidification occurs when the ocean absorbs carbon dioxide from the atmosphere or from the breakdown of organic matter, which then causes a chemical reaction to make it more acidic. Species as diverse as scallops and corals are vulnerable to ocean acidification, which can affect the growth of their shells and skeletons.

Research by NOAA’s William G. Sunda and Wei-jun Cai of the University of Georgia points to the process of eutrophication – the production of excess algae from increased nutrients, such as, nitrogen and phosphorus — as a large, often overlooked source of CO2 in coastal waters. When combined with increasing CO2 in the atmosphere, the release of CO2 from decaying organic matter is accelerating the acidification of coastal seawater.

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L’acidification des mers menace petits archipels et pays pauvres (in French)

Published 25 September 2012 Media coverage Closed

Les habitants des Comores, dans l’océan Indien, sont les plus menacés par l’acidification des mers due au réchauffement climatique, selon le classement établi par l’organisation américaine non gouvernementale Oceana. Viennent ensuite ceux du Togo, des îles Cook, des Kiribati et d’Erythrée.

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Acidifying seas threaten island nations’ food security

Published 25 September 2012 Media coverage Closed

Food security problems caused by climate change and ocean acidification will hit small island and coastal nations hardest, environmental group Oceana said on Monday

MONTEREY, California (Reuters) – Food security problems caused by climate change and ocean acidification will hit small island and coastal nations hardest, environmental group Oceana said on Monday.

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Ocean-based food security threatened in a high CO2 world

Published 25 September 2012 Newsletters and reports , Science Closed

Emissions from human activities are changing the ocean’s chemistry and temperature1, 2 in ways that threaten the livelihoods of those who depend on fish and seafood for all or part of their diets. The changes may reduce the amount of wild caught seafood that can be supplied by the oceans and also redistribute species, changing the locations at which seafood can be caught4 and creating instability for ocean-based food security, or seafood security. This report ranks nations based on the seafood security hardships they may experience by the middle of this century due to changing ocean conditions from climate change and ocean acidification. This is done by combining each nation’s exposure to climate change and ocean acidification, its dependence on and consumption of fish and seafood and its level of adaptive capacity based on several socioeconomic factors. Country rankings are developed for risks from climate change and ocean acidification independently, as well as from both problems combined.

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Climate change and ocean acidification – interactions with aquatic toxicology

Published 25 September 2012 Science Closed
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The possibilities for interactions between toxicants and ocean acidification are reviewed from two angles. First, it is considered how toxicant responses may affect ocean acidification by influencing the carbon dioxide balance. Second, it is introduced, how the possible changes in environmental conditions (temperature, pH and oxygenation), expected to be associated with climate change and ocean acidification, may interact with the toxicant responses of organisms, especially fish. One significant weakness in available data is that toxicological research has seldom been connected with ecological and physiological/biochemical research evaluating the responses of organisms to temperature, pH or oxygenation changes occurring in the natural environment. As a result, although there are significant potential interactions between toxicants and natural environmental responses pertaining to climate change and ocean acidification, it is very poorly known if such interactions actually occur, and can be behind the observed disturbances in the function and distribution of organisms in our seas.

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6th New Zealand Ocean Acidification Workshop – Southern contributions to a second decade of OA research

Published 24 September 2012 Meetings , Science Closed

University of Otago, Dunedin, 7-8 February 2013.

Theme:

Southern contributions to a second decade of OA research

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High tolerance of protozooplankton to ocean acidification in an Arctic coastal plankton community

Published 21 September 2012 Science Closed
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Impacts of ocean acidification (OA) on marine biota have been observed in a wide range of marine systems. We used a mesocosm approach to study the response of a high Arctic coastal protozooplankton (PZP in the following) community during the post-bloom period in the Kongsfjorden (Svalbard) to direct and indirect effects of high pCO2/low pH. We found almost no direct effects of OA on PZP composition and diversity. Both, the relative shares of ciliates and heterotrophic dinoflagellates as well as the taxonomic composition of protozoans remained unaffected by changes inpCO2/pH. The different pCO2 treatments did not have any effect on food availability and phytoplankton composition and thus no indirect effects e.g. on the total carrying capacity and phenology of PZP could be observed. Our data points at a high tolerance of this Arctic PZP community to changes in pCO2/pH. Future studies on the impact of OA on plankton communities should include PZP in order to test whether the observed low sensitivity of protozoans to OA is typical for coastal communities where changes in seawater pH occur frequently.

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A new conceptual model of coral biomineralisation: hypoxia as the physiological driver of skeletal extension

Published 21 September 2012 Science Closed
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That corals skeletons are built of aragonite crystals with taxonomy-linked ultrastructure has been well understood since the 19th century. Yet, the way by which corals control this crystallization process remains an unsolved question. Here, I outline a new conceptual model of coral biominerationsation that endeavours to relate known skeletal features with homeostatic functions beyond traditional growth (structural) determinants. In particular, I propose that the dominant physiological driver of skeletal extension is night-time hypoxia, which is exacerbated by the respiratory oxygen demands of the coral’s algal symbionts (= zooxanthellae). The model thus provides a new narrative to explain the high growth rate of symbiotic corals, by equating skeletal deposition with the “work-rate” of the coral host needed to maintain a stable and beneficial symbiosis. In this way, coral skeletons are interpreted as a continuous (long-run) recording unit of the stability and functioning of the coral-algae endosymbiosis. After providing supportive evidence for the model across multiple scales of observation, I use coral core data from the Great Barrier Reef (Australia) to highlight the disturbed nature of the symbiosis in recent decades, but suggest that its onset is consistent with a trajectory that has been followed since at least the start of the 1900’s. In concluding, I explain how the evolved capacity of the cnidarians (which now includes modern reef corals) to overcome the metabolic limitation of hypoxia via skeletogenesis, may underpin the sudden appearance in the fossil record of calcified skeletons at the Precambrian-Cambrian transition – and the ensuing rapid appearance of most major animal phyla.

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CO2-driven seawater acidification increases photochemical stress in a green alga

Published 21 September 2012 Science Closed
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Increased CO2 and associated acidification in seawater, known as ocean acidification, decreases calcification of most marine calcifying organisms. However, there is little information available on how marine macroalgae would respond to the chemical changes caused by seawater acidification. We hypothesized that down-regulation of bicarbonate acquisition by algae under increased acidity and CO2 levels would lower the threshold above which photosynthetically active radiation (PAR) becomes excessive. Juveniles of Ulva prolifera derived from zoospores were grown at ambient (390 µatm) and elevated (1000 µatm) CO2 concentrations for 80 days before the hypothesis was tested. Here, the CO2-induced seawater acidification increased the quantum yield under low levels of light, but induced higher nonphotochemical quenching under high light. At the same time, the PAR level at which photosynthesis became saturated was decreased and the photosynthetic affinity for CO2 or inorganic carbon decreased in the high-CO2 grown plants. These findings indicated that ocean acidification, as an environmental stressor, can reduce the threshold above which PAR becomes excessive.

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Fertilisation, embryogenesis and larval development in the tropical intertidal sand dollar Arachnoides placenta in response to reduced seawater pH

Published 21 September 2012 Science Closed
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We examined the response of the tropical sand dollar Arachnoides placenta to reduced seawater pH in experiments spanning ca. 50 % of the planktonic larval duration. A. placenta inhabits intertidal sandy beaches where we observed a minimum in situ pH range 0.06 pH units (pH 8.10–8.16). The responses of gametes and larvae to seawater pH were tested in vitro in ambient (pH 8.14, pCO2 = 525.7 μatm, total alkalinity = 2,651 μmol kg soln−1) and three reduced pH seawater treatments (7.8–7.0). Percentage fertilisation decreased significantly with decreasing pH across a range of sperm/egg ratios (4:1 up to 4,000:1). A. placenta reached the advanced pluteus stage in 4 days, and during this time, we saw no difference in survival rate of larvae between the ambient (67 %) and pH 7.79 (72 %) treatments. Four-day survival was, however, reduced to 44 and 11 % in the pH 7.65 and 7.12 treatments, respectively. Larval development and morphometrics varied among pH treatments. Embryos reared in pH 7.12 exhibited arrested development. Larvae reared at pH 7.65 showed delayed development and greater mortality compared with those reared at pH 7.79 and 8.14. When larval morphometrics are compared among larvae of the same size, differences in larval width and total arm length between pH treatments disappear. These results suggest that variation in larval size among the three highest pH treatments at a given time are likely the result of slower development and apparent shrinkage of surviving larvae and not direct changes in larval shape. There were no differences in the percentage inorganic content (a proxy for calcification) in larvae reared in either an ambient or a pH 7.7 treatment. The responses of fertilisation and development to decreased pH/increased pCO2 in A. placenta are within the range of those reported for other intertidal and subtidal echinoid species from colder latitudes.

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BLUE Ocean Film Festival seeks to inspire, educate, empower through cinema

Published 21 September 2012 Media coverage Closed
The BLUE Ocean Film Festival & Conservation Summit gets under way Monday night at the Sunset…

When Debbie Kinder, executive director of the BLUE Ocean Film Festival & Conservation Summit, was asked how this multifaceted ocean event has changed since its inaugural presence in Monterey in 2010, her response was, “It’s grown exponentially.”

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SUNY school to study ocean impact of greenhouse gas

Published 21 September 2012 Media coverage Closed

ALBANY — The State University of New York at Stony Brook will be studying how increasing concentrations of man-made greenhouse gases might impact ocean shellfish.

The National Oceanic and Atmospheric Administration gave the university a $533,000 grant for the work, which examines a phenomenon known as ocean acidification. Carbon dioxide, released during the combustion of oil, gasoline, coal and natural gas, is absorbed by the oceans, which is gradually raising theie acidity levels.

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Technical Note: A mobile sea-going mesocosm system – new opportunities for ocean change research

Published 20 September 2012 Science Closed
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One of the great challenges in ocean change research is to understand and forecast the effects of environmental changes on pelagic communities and the associated impacts on biogeochemical cycling. Mesocosms, experimental enclosures designed to approximate natural conditions, and in which environmental factors can be manipulated and closely monitored, provide a powerful tool to close the gap between single species laboratory experiments and observational and correlative approaches applied in field surveys. Existing pelagic mesocosm systems are stationary and/or restricted to well-protected waters. To allow mesocosm experimentation in a range of hydrographic conditions and in areas considered most sensitive to ocean change, we developed a mobile, sea-going mesocosm facility, the Kiel Off-Shore Mesocosms for Future Ocean Simulations (KOSMOS). The KOSMOS platform, which can be transported and deployed by mid-sized research vessels, is designed for operation in moored and free-floating mode under low to moderate wave conditions (up to 2.5 m wave heights). It encloses a water column 2 m in diameter and 15 to 25 m deep (~50–75 m3 in volume) without disrupting the vertical structure or disturbing the enclosed plankton community. Several new developments in mesocosm design and operation were implemented to (i) minimize differences in starting conditions between mesocosms, (ii) allow for extended experimental duration, (iii) precisely determine the mesocosm volume, (iv) determine air–sea gas exchange, and (v) perform mass balance calculations. After multiple test runs in the Baltic Sea, which resulted in continuous improvement of the design and handling, the KOSMOS platform successfully completed its first full-scale experiment in the high Arctic off Svalbard (78° 56.2′ N, 11° 53.6′ E) in June/July 2010. The study, which was conducted in the framework of the European Project on Ocean Acidification (EPOCA), focused on the effects of ocean acidification on a natural plankton community and its impacts on biogeochemical cycling and air/sea exchange of climate relevant gases. This manuscript describes the mesocosm hardware, its deployment and handling, CO2 manipulation, sampling and cleaning, including some further modifications conducted based on the experiences gained during this study.

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Technical Note: On the determination of enclosed water volume in large flexible-wall mesocosms

Published 20 September 2012 Science Closed
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The volume of water enclosed inside flexible-wall mesocosm bags is hard to estimate using geometrical calculations and can be strongly variable among bags of the same dimensions. Here we present a method for precise water volume determination in mesocosms using salinity as a tracer. Knowledge of the precise volume of water enclosed allows establishment of exactly planed treatment concentrations and calculation of elemental budgets.

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The importance of visitor perceptions in estimating how climate change will affect future tourist flows to the Great Barrier Reef

Published 20 September 2012 Science Closed
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A growing chorus of scientists (Hoegh-Guldberg, Mumby and Hooten 2007, IPCC 2007) are predicting the demise of coral reef systems as a direct consequence of climate change.

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Acidification concerns taken to Congress

Published 20 September 2012 Media coverage Closed

IN a bid to raise awareness of the problems that increasing ocean acidity is causing shellfish growers in North America, a number of scientists have shared their research with US politicians about the impending ecological and economic consequences of this trend.

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Clemson marine biologist seeks genetic pearls in oyster DNA

Published 20 September 2012 Media coverage , Science Closed

CLEMSON — The drab shell of an oyster is complex and the animal that lives inside can adapt to stressful living conditions, according to a team of marine biologists, including a Clemson University researcher, that identified and catalogued the genes of the Pacific oyster. Their research is published in the journal Nature this week.

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What is the big deal about ocean acidification?

Published 20 September 2012 Media coverage Closed

If you have been paying attention to environmental news lately you may have read or heard a little bit about this thing called ocean acidification. But what is ocean acidification and why is it such a big deal?

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Multi-partner interactions in corals in the face of climate change

Published 20 September 2012 Science Closed
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Recent research has explored the possibility that increased sea-surface temperatures and decreasing pH (ocean acidification) contribute to the ongoing decline of coral reef ecosystems. Within corals, a diverse microbiome exerts significant influence on biogeochemical and ecological processes, including food webs, organismal life cycles, and chemical and nutrient cycling. Microbes on coral reefs play a critical role in regulating larval recruitment, bacterial colonization, and pathogen abundance under ambient conditions, ultimately governing the overall resilience of coral reef systems. As a result, microbial processes may be involved in reef ecosystem-level responses to climate change. Developments of new molecular technologies, in addition to multidisciplinary collaborative research on coral reefs, have led to the rapid advancement in our understanding of bacterially mediated reef responses to environmental change. Here we review new discoveries regarding (1) the onset of coral-bacterial associations; (2) the functional roles that bacteria play in healthy corals; and (3) how bacteria influence coral reef response to environmental change, leading to a model describing how reef microbiota direct ecosystem-level response to a changing global climate.

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Woods Hole gets scallop study grant

Published 20 September 2012 Media coverage Closed

FALMOUTH — What is the acidification of the oceans going to do to the scallop population? That’s the question the Woods Hole Oceanographic Institution will try to answer with a $682,000, three-year, federal grant, the National Oceanic and Atmospheric Administration announced Wednesday.

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