Une expérience de grande ampleur à Villefranche-sur-Mer (video; in French)

PhD position: ocean acidification and/or plankton ecology and evolution

The Norwegian Polar Institute (NPI) is seeking a qualified and enthusiastic candidate for a PhD studentship in marine plankton ecology and evolution. The position is within the plankton/ecotoxicology group at NPI with affiliation to the Fram Centre Flagship “Ocean acidification and ecosystems effects in Northern waters”.

Tracking Climate Change in the Northern California Current pelagic ecosystem: response of zooplankton in the Oregon upwelling zone to large-scale climate forcing with thoughts on the looming problems of hypoxia and ocean acidification

Date and Time: February 28, 2013; 11:00-12:00 Pacific Time [Check U.S. Time clock for your local time]
Location: NOAA NWFSC Auditorium (2725 Montlake Blvd. E., Seattle, WA 98112)
Speaker(s): Bill Peterson NOAA NWFSC)
OneNOAA Science Seminar Sponsor: NOAA NWFSC Monster JAM seminars
Abstract: TBD

Ocean acidification: is the sky really falling?

Date and Time: February 28, 2013; 16:00-17:00 Eastern Time [Check U.S. Time clock for your local time]
Location: Online Access Only
Speaker(s): Dr. Jeremy Mathis (NOAA PMEL)
OneNOAA Science Seminar Sponsor: NOAA NOAA Office of National Marine Sanctuaries West Coast Region
Abstract: In the last two and a half centuries, but mainly in the past fifty years, the pH of the ocean has been reduced due to the intrusion of anthropogenic CO2 produced mainly from fossil fuel burning and changes in land use practices. This reduction in pH could have far-reaching and detrimental consequences for a number of marine species, particularly those that produce carbonate shells. The changing chemistry will likely impact the food we gather from the ocean. Dr. Mathis will provide insight in this ecological frontier from the rivers to the sea and how ocean acidification will influence our lives.

Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO₂) emissions. A major sink for atmospheric CO₂, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs) 2.6 and 8.5 using an intermediate complexity global ecosystem model, Medusa–2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s) in ocean productivity (−6.3%). This impact has knock-on consequences for the abundances of the low trophic level biogeochemical actors modelled by Medusa–2.0 (−5.8%), and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m), and in the volume of ocean suboxic zones (+12.5%). A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change, and changes are much more pronounced under RCP 8.5 than the RCP 2.6 scenario.

Controlled experimental aquarium system for multi-stressor investigation: carbonate chemistry, oxygen saturation, and temperature

As the field of ocean acidification has grown, researchers have increasingly turned to laboratory experiments to understand the impacts of increased CO₂ on marine organisms. However, other changes such as ocean warming and deoxygenation are occurring concurrently with the increasing CO₂ concentrations, complicating the anthropogenic impact on organisms. This experimental aquarium design allows for independent regulation of CO₂ concentration, O₂ levels, and temperature in a controlled environment to study the impacts of multiple stressors. The system has the flexibility for a wide range of treatment chemistry, seawater volumes, and study organisms. Control of the seawater chemistry is achieved by equilibration of a chosen gas mixture with seawater using a Liqui-Cel^® membrane contactor. Included as examples, two experiments performed using the system have shown control of CO₂ between approximately 500–1400 μatm and O₂ from 80–240 μmol kg⁻¹. Temperature has been maintained to 0.5 °C or better in the range of 10–17 °C. On a weeklong timescale, control results in variability in pH of less than 0.007 pH units and in oxygen concentration less than 3.5 μmol kg⁻¹. Longer experiments, over a month, have been completed with reasonable but lessened control, still better than 0.08 pH units and 13 μmol kg⁻¹ O₂. The ability to study the impacts of multiple stressors in the laboratory simultaneously, as well as independently, will be an important part of understanding the response of marine organisms to a high-CO₂ world.