Call for bids to organize and host the “4th Symposium on the Ocean in a High-CO2 World” in 2016

The 4th symposium on the Ocean in a High-CO2 World is planned to be held in 2016.  The symposium will maintain its focus on ocean acidification and associated impacts on marine organisms, ecosystems, and biogeochemical cycles. It will consider acidification in the context of other global changes such as warming and deoxygenation, particularly the combined actions of these multiple stressors. Furthermore, it will cover socioeconomic consequences of ocean acidification, including policy and management.

Deadline for bids: before 1 october 2014
Send to: James Orr (james.orr(at)lsce.ipsl.fr)

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Multiple stressors threatening the future of the Baltic Sea–Kattegat marine ecosystem: Implications for policy and management actions

The paper discusses the combined effects of ocean acidification, eutrophication and climate change on the Baltic Sea and the implications for current management strategies. The scientific basis is built on results gathered in the BONUS+ projects Baltic-C and ECOSUPPORT. Model results indicate that the Baltic Sea is likely to be warmer, more hypoxic and more acidic in the future. At present management strategies are not taking into account temporal trends and potential ecosystem change due to warming and/or acidification, and therefore fulfilling the obligations specified within the Marine Strategy Framework Directive, OSPAR and HELCOM conventions and national environmental objectives may become significantly more difficult. The paper aims to provide a basis for a discussion on the effectiveness of current policy instruments and possible strategies for setting practical environmental objectives in a changing climate and with multiple stressors.

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One size fits all: stability of metabolic scaling under warming and ocean acidification in echinoderms

Responses by marine species to ocean acidification (OA) have recently been shown to be modulated by external factors including temperature, food supply and salinity. However the role of a fundamental biological parameter relevant to all organisms, that of body size, in governing responses to multiple stressors has been almost entirely overlooked. Recent consensus suggests allometric scaling of metabolism with body size differs between species, the commonly cited ‘universal’ mass scaling exponent (b) of ¾ representing an average of exponents that naturally vary. One model, the Metabolic-Level Boundaries hypothesis, provides a testable prediction: that b will decrease within species under increasing temperature. However, no previous studies have examined how metabolic scaling may be directly affected by OA. We acclimated a wide body-mass range of three common NE Atlantic echinoderms (the sea star Asterias rubens, the brittlestars Ophiothrix fragilis and Amphiura filiformis) to two levels of pCO2 and three temperatures, and metabolic rates were determined using closed-chamber respirometry. The results show that contrary to some models these echinoderm species possess a notable degree of stability in metabolic scaling under different abiotic conditions; the mass scaling exponent (b) varied in value between species, but not within species under different conditions. Additionally, we found no effect of OA on metabolic rates in any species. These data suggest responses to abiotic stressors are not modulated by body size in these species, as reflected in the stability of the metabolic scaling relationship. Such equivalence in response across ontogenetic size ranges has important implications for the stability of ecological food webs.

Continue reading ‘One size fits all: stability of metabolic scaling under warming and ocean acidification in echinoderms’

In Washington, oyster farms declining due to ocean acidification

It was in 2002 that the family-owned Nisbet Oyster Company first noticed a drop in their adult oyster populations. By 2012, their oyster production had declined by 42 percent. This is a serious problem for Washington, which is home to one of the most productive oyster farming areas in the United States, Willapa Bay. According to the Washington government, the shellfish industry employs over 3,200 people and provides an annual economic contribution of $270 million statewide. The sizable drop in oyster populations forced the state to act, and it convened a Blue Ribbon panel to assess the root of the problem in late 2012.

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Ocean acidification risk assessment for Alaska’s fishery sector

The highly productive fisheries of Alaska are located in seas projected to experience strong global change, including rapid transitions in temperature and ocean acidification -driven changes in pH and other chemical parameters. Many of the marine organisms that are most intensely affected by ocean acidification (OA) contribute substantially to the state’s commercial fisheries and traditional subsistence way of life. Prior studies of OA’s potential impacts on human communities have focused only on possible direct economic losses from specific scenarios of human dependence on commercial harvests and damages to marine species. However, other economic and social impacts, such as changes in food security or livelihoods, are also likely to result from climate change. This study evaluates patterns of dependence on marine resources within Alaska that could be negatively impacted by OA and current community characteristics to assess the potential risk to the fishery sector from OA. Here, we used a risk assessment framework based on one developed by the Intergovernmental Panel on Climate Change to analyze earth-system global ocean model hindcasts and projections of ocean chemistry, fisheries harvest data, and demographic information. The fisheries examined were: shellfish, salmon and other finfish. The final index incorporates all of these data to compare overall risk among Alaska’s federally designated census areas. The analysis showed that regions in southeast and southwest Alaska that are highly reliant on fishery harvests and have relatively lower incomes and employment alternatives likely face the highest risk from OA. Although this study is an intermediate step toward our full understanding, the results presented here show that OA merits consideration in policy planning, as it may represent another challenge to Alaskan communities, some of which are already under acute socio-economic strains.

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Lecture: Sensitivity of coral trout (Plectropomus) to increasing temperature, ocean acidification and habitat degradation

Presented by: Prof Morgan Pratchett, ARC CoE Coral Reef Studies, Townsville
When: Thursday, 24th of July 2014; 12:00 to 13:00 hrs
Where: Building 19 (Kevin Stark Research Building), Room #106 (upstairs), JCU, Townsville. Video-linked to the University of Queensland (GCI Boardroom, Level 7, Gehrmann Building 60.

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Processes determining the marine alkalinity and carbonate saturation distributions

We introduce a composite tracer, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* also highlights riverine alkalinity plumes that are due to dissolved calcium carbonate from land. We estimate the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation lowers basin mean Indian and Atlantic Alk*, while upwelling of dissolved CaCO3 rich deep waters elevates Northern Pacific and Southern Ocean Alk*. We use the Alk* distribution to estimate the carbonate saturation variability resulting from CaCO3 cycling and other processes. We show regional variations in surface carbonate saturation are due to temperature changes driving CO2 fluxes and, to a lesser extent, freshwater cycling. Calcium carbonate cycling plays a tertiary role. Monitoring the Alk* distribution would allow us to isolate the impact of acidification on biological calcification and remineralization.

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