Archive for November, 2009

New Report card on Marine Climate Change in Australia (audio)

Concern over increasing greenhouse gases tend to concentrate on the level of CO2 in the atmosphere, but our oceans are also being affected.

The first ever Australian report card on the impact of climate change on our marine environment was released on Friday.

More than seventy marine scientists were involved in the work, which has found Australian ocean temperatures are warming, changes in marine biodiversity and ocean acidification.

DR WILL HOWARD from the Antarctic Climate & Ecosystems Cooperative Research Centre was a contributor to the report card and says it provides an up to date summary of what we know about the impacts of climate change on the marine environment, and importantly what we don’t know…
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Vulnerability of marine biodiversity to ocean acidification: A meta-analysis

The ocean captures a large part of the anthropogenic carbon dioxide emitted to the atmosphere. As a result of the increase in CO2 partial pressure the ocean pH is lowered as compared to pre-industrial times and a further decline is expected. Ocean acidification has been proposed to pose a major threat for marine organisms, particularly shell-forming and calcifying organisms. Here we show, on the basis of meta-analysis of available experimental assessments, differences in organism responses to elevated pCO2 and propose that marine biota may be more resistant to ocean acidification than expected. Calcification is most sensitive to ocean acidification while it is questionable if marine functional diversity is impacted significantly along the ranges of acidification predicted for the 21st century. Active biological processes and small-scale temporal and spatial variability in ocean pH may render marine biota far more resistant to ocean acidification than hitherto believed.
Continue reading ‘Vulnerability of marine biodiversity to ocean acidification: A meta-analysis’

Upcoming Workshop: Ocean acidification: what it is, what we know, and what it may mean

Topics in Oceanography Professional Development Workshops
Saturday December 12, 2009, 9:00-2:30
Woods Hole Oceanographic Institution
“Ocean acidification: what it is, what we know, and what it may mean”

Sarah Cooley, WHOI Marine Chemistry and Geochemistry Department
Anne Cohen, WHOI Geology and Geophysics Department
Heather Benway, Ocean Carbon and Biogeochemistry Project Office

– Hear how ocean water chemistry is changing, and how the changes may affect marine life and people

– Hands-on demonstration of classroom experiments and kits on ocean acidification
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Oceana advertising campaign in Copenhagen

Because the changing chemistry of the ocean threatens all marine life, Oceana has invested in an advertising campaign to highlight the most urgent goal: reducing CO2 emissions to achieve atmospheric levels of 350 parts per million (ppm) or less as soon as possible.

The three advertisements that Oceana will display in Copenhagen, Denmark, throughout the entire United Nations Framework Convention on Climate Change (UNFCCC) meeting, are depicted here.
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Individual and interacting effects of pCO2 and temperature on Emiliania huxleyi calcification: study of the calcite production, the coccolith morphology and the coccosphere size

The impact of ocean acidification and increased water temperature on marine ecosystems, in particular those involving calcifying organisms, has been gradually recognised. We examined the individual and combined effects of increased pCO2 (180 ppm V CO2, 380 ppm V CO2 and 750 ppm V CO2 corresponding to past, present and future CO2 conditions, respectively) and temperature (13°C and 18°C) during the calcification phase of the coccolithophore E. huxleyi using batch culture experiments. We showed that the cell abundance-normalized particulate organic carbon concentration (POC) increased from the present to the future CO2 treatments. A significant effect of pCO2 and of temperature on calcification was found, manifesting itself in a lower cell abundance-normalized particulate inorganic carbon (PIC) content as well as a lower PIC:POC ratio at future CO2 levels and at 18°C. Coccosphere-sized particles showed a size reduction trend with both increasing temperature and CO2 concentration. The influence of the different treatments on coccolith morphology was studied by categorizing SEM coccolith micrographs. The number of well-formed coccoliths decreased with increasing pCO2 while temperature did not have a significant impact on coccolith morphology. No interacting effect of pCO2 and temperature was observed on calcite production, coccolith morphology or on coccosphere size. Finally, our results suggest that ocean acidification might have a larger adverse impact on coccolithophorid calcification than surface water warming.
Continue reading ‘Individual and interacting effects of pCO2 and temperature on Emiliania huxleyi calcification: study of the calcite production, the coccolith morphology and the coccosphere size’

Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida

To analyze the relation between seawater uptake and calcification, we incubated juveniles of the benthic foraminifer Ammonia tepida with various fluorescent probes and visualised them afterwards with confocal laser scanning microscopy. Vesicle membranes, Ca ions and vacuole fluids were followed with various tracers and showed for the first time that endocytosis of seawater is part of the calcification process in Ammonia tepida. Data on the intracellular Ca ion cycling allowed for calculating a preliminary cellular Ca budget during foraminiferal calcification. This showed that the free calcium involved in the production of a new chamber cannot be sufficient and suggests that foraminifera may precipitate their calcite from an amorphous precursor.
Continue reading ‘Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida’

Bermuda’s pink sands under threat as seas become more acidic

Bermuda may soon have to remove “pink sandy beaches” from its tourism advertising, if the chemistry of the ocean continues to change.

The foraminifera Homotrema rubrum which gives the blush to Bermuda beaches, is one of the many ocean organisms that scientists think will be badly affected by oceans becoming more acidic .

The Royal Gazette met with Bermuda Institute of Ocean Sciences (BIOS) scientists Andreas J. Andersson, Nick R. Bates, and Samantha J. de Putron to talk about the Bermuda Ocean Acidification Coral Reef Investigation (BEACON), a BIOS project designed to study ocean acidification and its effects on Bermuda’s coral reef.
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Rate of Iceland Sea acidification from time series measurements (update)

The Iceland Sea is one part of the Nordic Seas. Cold Arctic Water prevails there and the deep-water is an important source of North Atlantic Deep Water. We have evaluated time series observations of measured pCO2 and total CO2 concentration from discrete seawater samples during 1985–2008 for the surface and 1994–2008 for deep-water, and following changes in response to increasing atmospheric carbon dioxide. The surface pH in winter decreases at a rate of 0.0024 yr−1, which is 50% faster than average yearly rates at two subtropical time series stations, BATS and ESTOC. In the deep-water regime (>1500 m), the rate of pH decline is a quarter of that observed in surface waters. The surface seawater carbonate saturation states (Ω) are about 1.5 for aragonite and 2.5 for calcite, about half of levels found in subtropical surface waters. During 1985–2008, the degree of saturation (Ω) decreased at an average rate of 0.0072 yr−1 for aragonite and 0.012 yr−1 for calcite. The aragonite saturation horizon is currently at 1710 m and shoaling at 4 m yr−1. Based on this rate of shoaling and on the local hypsography, each year another 800 km2 of seafloor becomes exposed to waters that have become undersaturated with respect to aragonite.

Continue reading ‘Rate of Iceland Sea acidification from time series measurements (update)’

VIRTUALURCHIN interactive tutorials

Gametes of sea urchins yield exceptional experiences in the classroom; teachers and students alike are riveted by being able to observe fertilization, cell division and embryonic development. The gametes are easy to use, the developmental stages are readily seen with the microscope and the rapidity of fertilization and early cell divisions allows the student to ask questions and obtain answers within the bounds of a normal classroom schedule. The utility of urchins for inquiry-based science is unrivaled.
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Ocean acidification in WAMC Northeast Public Radio (audio)

Guests NOAA Ocean Chemist Richard Feely and Filmmakers Sven Huseby and Barbara Ettinger answer questions about ocean acidification. Alan Chartock hosts.
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Ocean acidification in the IPCC AR5 WG II

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