Archive for December, 2009

Kiel-KOSMOS – Leibniz-Institut für Meereswissenschaften an der Universität Kiel

The Kiel Off-Shore Mesocosms for future Ocean Simulations – KOSMOS – at IFM-GEOMAR is a newly established ocean observatory and experimentation system for deployment in open waters. A first prototype designed in 2005 was progressively improved based on numerous tests in wave simulation tanks and in the field. With its first full-scale field applications in the Gotland Sea, Proper Baltic in the summer of 2007 and 2008 KOSMOS is the first mesocosm system worldwide successfully operated in off-shore waters.

Continue reading ‘Kiel-KOSMOS – Leibniz-Institut für Meereswissenschaften an der Universität Kiel’

More carbon dioxide may create a racket in the seas

Here is another consequence of rising carbon dioxide emissions: the oceans are getting louder.

Continue reading ‘More carbon dioxide may create a racket in the seas’

Testing the effects of ocean acidification on algal metabolism: considerations for experimental designs

Ocean acidification describes changes in the carbonate chemistry of the ocean due to the increased absorption of anthropogenically released CO2. Experiments to elucidate the biological effects of ocean acidification on algae are not straightforward because when pH is altered, the carbon speciation in seawater is altered, which has implications for photosynthesis and, for calcifying algae, calcification. Furthermore, photosynthesis, respiration, and calcification will themselves alter the pH of the seawater medium. In this review, algal physiologists and seawater carbonate chemists combine their knowledge to provide the fundamental information on carbon physiology and seawater carbonate chemistry required to comprehend the complexities of how ocean acidification might affect algae metabolism. A wide range in responses of algae to ocean acidification has been observed, which may be explained by differences in algal physiology, timescales of the responses measured, study duration, and the method employed to alter pH. Two methods have been widely used in a range of experimental systems: CO2 bubbling and HCl/NaOH additions. These methods affect the speciation of carbonate ions in the culture medium differently; we discuss how this could influence the biological responses of algae and suggest a third method based on HCl/NaHCO3 additions. We then discuss eight key points that should be considered prior to setting up experiments, including which method of manipulating pH to choose, monitoring during experiments, techniques for adding acidified seawater, biological side effects, and other environmental factors. Finally, we consider incubation timescales and prior conditioning of algae in terms of regulation, acclimation, and adaptation to ocean acidification.
Continue reading ‘Testing the effects of ocean acidification on algal metabolism: considerations for experimental designs’

Acidification- History Channel & Smithsonian Institution (video)

The ocean naturally absorbs millions of tons of carbon each day, and as CO2 levels in the atmosphere rise, the balance is tipping and the ocean is becoming more acidic. Researchers in Peru are investigating ocean acidification there and how it might affect ecosystems, fisheries, and people around the world.

Continue reading ‘Acidification- History Channel & Smithsonian Institution (video)’

Acidic oceans threaten world’s ecosystem

Deep and immediate cuts in emissions are needed to stall ocean acidification and prevent mass extinction of marine species, food insecurity and serious damage to the world economy, according to International Union for the Conservation of Nature (IUCN).

Continue reading ‘Acidic oceans threaten world’s ecosystem’

Ocean acidification: present conditions and future changes in a high-CO2 world

The uptake of anthropogenic CO2 by the global ocean induces fundamental changes in seawater chemistry that could have dramatic impacts on biological ecosystems in the upper ocean. Estimates based on the Intergovernmental Panel on Climate Change (IPCC) business-as-usual emission scenarios suggest that atmospheric CO2 levels could approach 800 ppm near the end of the century. Corresponding biogeochemical models for the ocean indicate that surface water pH will drop from a pre-industrial value of about 8.2 to about 7.8 in the IPCC A2 scenario by the end of this century, increasing the ocean’s acidity by about 150% relative to the beginning of the industrial era. In contemporary ocean water, elevated CO2 will also cause substantial reductions in surface water carbonate ion concentrations, in terms of either absolute changes or fractional changes relative to pre-industrial levels. For most open-ocean surface waters, aragonite undersaturation occurs when carbonate ion concentrations drop below approximately 66 µmol kg-1. The model projections indicate that aragonite undersaturation will start to occur by about 2020 in the Arctic Ocean and 2050 in the Southern Ocean. By 2050, all of the Arctic will be undersaturated with respect to aragonite, and by 2095, all of the Southern Ocean and parts of the North Pacific will be undersaturated. For calcite, undersaturation occurs when carbonate ion concentration drops below 42 µmol kg-1. By 2095, most of the Arctic and some parts of the Bering and Chukchi seas will be undersaturated with respect to calcite. However, in most of the other ocean basins, the surface waters will still be saturated with respect to calcite, but at a level greatly reduced from the present.

Continue reading ‘Ocean acidification: present conditions and future changes in a high-CO2 world’

An accounting of the observed increase in oceanic and atmospheric CO2 and an outlook for the future

Observations of CO2 accumulation in the atmosphere and ocean show that they are approximately equal to the total amount emitted by burning of fossil fuels since 1850. A mass balance calculation is carried out with ocean uptake satisfying two observed constraints, and with net terrestrial emissions as the remainder. The calculation illustrates that before 1940, net terrestrial emissions were positive, and have been negative since then, making their cumulative contribution in 2008 rather small. The overall evidence strongly suggests that the increase of CO2 in the atmosphere is 100% due to human activities, and is dominated by fossil fuel burning. Some simple projections of atmospheric CO2, and therefore also of surface pCO2 for most of the ocean, are made with plausible future scenarios of fossil fuel emissions, only taking into account features of the carbon cycle that are quite well established.

Continue reading ‘An accounting of the observed increase in oceanic and atmospheric CO2 and an outlook for the future’

Ocean acidification: A critical emerging problem for the ocean sciences

Over a period of less than a decade, ocean acidification—the change in seawater chemistry due to rising atmospheric carbon dioxide (CO2) levels and subsequent impacts on marine life—has become one of the most critical and pressing issues facing the ocean research community and marine resource managers alike. The objective of this special issue of Oceanography is to provide an overview of the current scientific understanding of ocean acidification as well as to indicate the substantial gaps in our present knowledge. Papers in the special issue discuss the past, current, and future trends in seawater chemistry; highlight potential vulnerabilities to marine species, ecosystems, and marine resources to elevated CO2; and outline a roadmap toward future research directions. In this introductory article, we present a brief introduction on ocean acidification and some historical context for how it emerged so quickly and recently as a key research topic.

Continue reading ‘Ocean acidification: A critical emerging problem for the ocean sciences’

Joint IPCC Expert Meeting of WGI and WGII on Impacts of Ocean Acidification on Marine Biology and Ecosystems

February 2011 (exact dates TBD) — Japan

The oceans currently absorb about one-third of fossil fuel CO2 emitted to the atmosphere and have, as a consequence, been increasing in acidity. Ocean acidification is now recognized as a critical component of global change, potentially responsible for a wide range of impacts on ecosystems, with subsequent consequences on livelihoods and food security. Further, one important aspect is that more CO2 mitigation may be required to achieve particular stabilization targets, because acidification limits the ability of the oceans to continue to absorb CO2. Previous IPCC assessment reports considered biogeochemical and temperature effects of anthropogenic carbon on the oceans, but the direct impacts of ocean acidification, its combined effects with ocean warming on marine ecosystems and productivity, and potential feedbacks to the climate system have not been fully assessed.

Continue reading ‘Joint IPCC Expert Meeting of WGI and WGII on Impacts of Ocean Acidification on Marine Biology and Ecosystems’

Hilary Benn calls for action on ocean acidification (video)

Ocean acidification is a threat to marine life and our food supply, UK Environment Secretary Hilary Benn warned on 14 December, in a speech to mark Oceans Day at the United Nations Climate Change conference. Addressing delegates in Copenhagen, Mr Benn explained that in the past 150 years, the oceans have absorbed half of all the carbon dioxide that we as human beings have generated. “We need to tell the story of the damage we are doing to our seas as we seek to do something about it here in Copenhagen this week,” he added.

Continue reading ‘Hilary Benn calls for action on ocean acidification (video)’

Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,428,650 hits


Ocean acidification in the IPCC AR5 WG II

OUP book