Archive for August, 2011

Dr Malte Meinshausen report on the contribution of the Wandoan Coal Mine to climate change and ocean acidification

INTRODUCTION

1. I have been asked by the Environmental Defenders Office (EDO) on behalf of Friends of the Earth – Brisbane Co-Op Ltd to provide an expert report on the resilience of the climate to emissions of greenhouse gases from the proposed Wandoan Coal Mine in Queensland, Australia. Other experts, including Professor Ove Hoegh-Guldberg are addressing related issues in separate reports, including ocean acidification. The reports are to assist the Land Court of Queensland in an objections hearing regarding the proposed mine.
Continue reading ‘Dr Malte Meinshausen report on the contribution of the Wandoan Coal Mine to climate change and ocean acidification’

Scientist creates new hypothesis on ocean acidification

A researcher at the Hawai‘i Institute of Marine Biology, an organized research unit in the University of Hawai‘i at Mānoa’s School of Ocean and Earth Science and Technology has come up with a new explanation for the effects of ocean acidification on coral reefs.

Since the beginning of the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has been rising due to the burning of fossil fuels. Increased absorption of this carbon by the ocean is lowering the seawater pH (the scale which measures how acidic or basic a substance is) and aragonite saturation state in a process known as ocean acidification. Aragonite is the mineral form of calcium carbonate that is laid down by corals to build their hard skeleton. Researchers wanted to know how the declining saturation state of this important mineral would impact living coral populations.
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Skeptical Science: OA not OK

Skeptical Science has published a series of 18 blog articles on ocean acidification authored by Doug Mackie, Christina McGraw, and Keith Hunter.
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Growth of threee species of Mediterranean cold-water corals exposed to ocean acidification

Increasing pCO2 in the atmosphere results in ocean acidification. The changes in ocean chemistry posed by such phenomenon pose an imminent threat to calcifying organisms such as cold-water waters corals. Very little information is available on the effect such threat poses on cold-water corals, particularly in the Mediterranean frontier. Three species of Mediterranean cold water corals (Lophelia pertusa, Madrepora oculata and Desmophyllum sp) were exposed to ocean acidification conditions. Four separate pCO2 treatments were represented: 412 ± 73 ppm, 497 ± 117 ppm, 665 ± 100 ppm, and 866± 191 ppm. Coral response was measured using several methods of assessing growth: buoyant weight, colour (area) projection, new polyp development, and skeletal density. Response to ocean acidification was shown to be species specific with Lophelia pertusa being generally more affected (a reduction of over 40% buoyant weight per day on higher pCO2 compared to lowest pCO2) than Madrepora oculata. Growth rate was not clearly influenced by ocean acidification in Desmophyllum sp. After 9 months of experiment, polyp development and skeletal density were not significantly altered by ocean acidification. A reduction in projected colour (area) was observed for both Madrepora oculata and Lophelia pertusa area under medium and high ocean acidification scenarios (Madrepora oculata over 50% colour (area) per day on higher pCO2 compared to lowest pCO2 ; Lophelia pertusa nearly 50% colour (area) per day on higher pCO2 compared to lowest pCO2). Response of the three species assessed was not linear, possibly due to several sources of variation interacting with acidification. That Lophelia pertusa consistently performs better at lower acidification scenarios has implications for the future of the deep-sea coral community and species associated. More studies are needed to assess whether the response observed here is consistent across other sites and cold-water species.
Continue reading ‘Growth of threee species of Mediterranean cold-water corals exposed to ocean acidification’

Anthropogenic CO2 fluxes in the Otranto Strait (e. Mediterranean) in February 1995

This study presents the distribution and fluxes of dissolved inorganic carbon (CT), total alkalinity (AT) and anthropogenic carbon (Cant) along the Otranto strait, during February 1995. Based on a limited number of properties (temperature, dissolved oxygen, total alkalinity and dissolved inorganic carbon), the composite tracer TrOCA was used to estimate the concentration of anthropogenic CO2 in the Otranto strait.

Total alkalinity exhibits high values and weak variability throughout the water column of the strait, probably associated with the dense water formation processes in the Adriatic basin, that induce a rapid transport of the coastal alkalinity to the deep waters. Elevated Cant concentrations and high anthropogenic pH variations are observed in the bottom layer of the strait, associated with the presence of Adriatic Deep Water (ADW). The study shows that large amounts of Cant have penetrated the highly alkaline Eastern Mediterranean waters, thereby causing a significant pH reduction since the pre-industrial era.

Estimates of the transports of CT and Cant through the strait indicate that during February 1995, the Adriatic Sea imports through the Otranto strait natural and anthropogenic carbon and acts as a net sink of carbon for the Ionian Sea. The anthropogenic carbon that is imported to the Adriatic Sea represents less than 1% of the net CT inflow. The Levantine Intermediate Water (LIW) contributes to about one third of the total CT and Cant inflow. Although the amounts of Cant annually transported by LIW and ADW are almost equal, the contribution of Cant to the CT transported by each water mass is slightly higher in ADW (3.1%) than in LIW (2.6%), as a result of its higher mean Cant concentration. The ADW despite its weak contribution to the total outflow of Cant, has a vital role for the sequestration and storage of the anthropogenic carbon, as this water mass is the main component of the Eastern Mediterranean Deep Waters and, thus, the anthropogenic CO2 is transferred in the deep horizons of the Eastern Mediterranean, where it remains isolated for many years.
Continue reading ‘Anthropogenic CO2 fluxes in the Otranto Strait (e. Mediterranean) in February 1995’

Warming of the Mediterranean Sea hampers the resistance of corals and mollusks to ocean acidification

Some calcifiers (mussels, gastropods and corals) protect their shell or skeleton from the corrosive effects of increasing ocean acidification. They can therefore resist some of the damaging effects of increasing ocean acidity generated by the release of carbon dioxide (CO2) in the atmosphere through human activities. This resistance is diminished when organisms are exposed to extended period of elevated temperature (28.5°C). This is a result of an international study (1), co-led by Jean-Pierre Gattuso, research scientist at Laboratoire d’océanographie de Villefranche (CNRS/UPMC), published in the journal Nature Climate Change. These results suggest that the ongoing and future warming of the Mediterranean combined with the rise of its acidity will increase the frequency of mass-mortality events.

The oceans absorb about one fourth of the carbon dioxide (CO2) released by the use of fossil fuel and changes in land use. This amounts to 1 million tons CO2 every hour and leads to large changes in the chemistry of seawater, including an increase in its acidity. This acidification threatens calcifying organisms, those that build shells and skeletons, such as mollusks and corals.
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PhD positions in interdisciplinary marine research, Germany 2011

PhD Research Positions in Interdisciplinary Marine Research at University of Kiel, Germany 2011

Study Subject(s):Marine Research (ocean acidification,ecosystem change,marine resources,ocean warming ,sea level rise , ocean hazards, marine life science , ocean governance)
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Associate research fellow in ecophysiology of ocean acidification

Ref. P42385
Salary: £24,370 per annum

Fixed Term contract for 13 months

The College of Life and Environmental Sciences wishes to appoint a Postdoctoral Researcher to work in the laboratories of Drs Rod Wilson and Ceri Lewis on a NERC funded grant, to start as soon as possible. This is part of the UKOARP (Ocean Acidification Research Programme) and the project is a collaboration with Swansea University, Plymouth Marine Laboratory, and Strathclyde University. The project will investigate the effects of temperature and CO2 on the early life stages of marine invertebrates and fish of commercial importance. The PDRA will be based at Exeter, using our new state-of-the-art £6M aquarium facility, and will regularly visit the Centre for Sustainable Aquaculture Research (http://www.aquaculturewales.com/) in Swansea to work on animals undergoing longer term exposures. Data on growth, performance, fitness etc. will feed into population modelling studies and ultimately allow us to address the socio-economic impacts of future ocean conditions on these species.

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Threshold of carbonate saturation state determined by a CO2 control experiment

Acidification of the oceans by increasing anthropogenic CO2 emissions will cause a decrease in biogenic calcification and an increase in carbonate dissolution. Previous studies suggest that carbonate dissolution will occur in polar regions and in the deep-sea oceans where saturation state with respect to carbonate minerals (Ω) will be <1 by 2100. However, carbonate in coral reefs distributed in tropical zones will not dissolve because the major carbonate in such reefs is aragonite, and the saturation state with respect to aragonite (Ω_a) is >1. Recent reports demonstrated nocturnal carbonate dissolution reefs, despite Ω_a > 1, probably relate to the dissolution of the minor reef carbonate (Mg-calcite), which is more soluble than aragonite. However, the threshold of Ω for the dissolution of natural sediments has not been clearly determined, and it is unknown whether these dissolution processes actually occur under natural conditions. This work describes the measurement of the dissolution rates of coral aragonite and Mg calcite excreted by marine organisms under conditions of Ω_a > 1 with controlled seawater pCO2. Laboratory experimental data of the present study show that bulk carbonate sediments sampled from a coral reef start to dissolve when Ω_a = 3.7, and dissolution rates increase with falling Ω_a. Mg-calcite derived from foraminifera and coralline algae dissolved when Ω_a reached 3.4, whereas coralline aragonite started to dissolve when Ω_a was almost 1.0. We show that nocturnal carbonate dissolution of coral reefs occurs mainly by the dissolution of foraminifera and coralline algae in reef sediment.
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Postdoctoral fellowship in coral biogeochemistry at Rutgers University

Postdoctoral Fellowship available at the Institute of Marine and Coastal Sciences at Rutgers, the State University of New Jersey. We are seeking a highly motivated researcher to conduct independent and collaborative research into the mechanisms of biomineralization in corals, its potential response to ocean acidification and implications for the application of geochemical proxies in corals, with an emphasis on boron isotopes. Preferred fields of experience include:
1) Interactions between biomolecules (“organic matrix”) and the formation of inorganic crystals in biogenic minerals.
2) Biomineraliztion controls on boron isotopes and other proxies of the seawater carbonate system in tropical corals, with an emphasis on controlled laboratory experiments.
Continue reading ‘Postdoctoral fellowship in coral biogeochemistry at Rutgers University’


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