Archive for September, 2011

Ocean acidification research in Antarctica

While the debate surrounding climate change has become mainstream news over the past few years, ocean acidification has only recently started to gain media attention. Ocean acidification has been dubbed ‘the other CO2 problem’ and research is gathering pace to determine potential consequences of increasing ocean acidity.
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Detecting ocean acidification

IOOS monitoring of our acidifying oceans is helping both the economy and environmental understanding. In terms of the economy, ocean observation sees a multiplied return on investment among many industries. The shellfish industry provides one illustration. IOOS efforts helped bring oyster hatcheries back from the brink of disaster within just a few years. With a $500,000 federal investment in coastal seawater monitoring, some businesses are again major contributors to the $111 million West Coast shellfish industry.
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Invited talk: Prof Mary A Sewell, School of Biological Sciences, The University of Auckland

On 06/10/2011 we are hosting our distinguished collaborator – Prof Mary A Sewell from the Marine Invertebrate Research Group at the School of Biological Sciences, The University of Auckland. Prof Sewell career started at the University of Auckland with a BSc and MSc in Zoology, followed by a PhD at the University of Alberta in Canada.  Subsequently she received two prestigious post-doctoral fellowships at Simon Fraser University, Harbor Branch Oceanographic Institution, and the University of Southern California, before returning to the University of Auckland in 1999.

On Thursday 06/10 at 4 pm Prof Sewell will present a lecture entitled: “Ocean Acidification: Integrating chemistry and marine biology and what it means for you.”

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Coral reefs modify their seawater carbon chemistry – case study from a barrier reef (Moorea, French Polynesia)

Changes in the carbonate chemistry of coral reef waters are driven by carbon fluxes from two sources: concentrations of CO2 in the atmospheric and source water, and the primary production/respiration and calcification/dissolution of the benthic community. Recent model analyses have shown that, depending on the composition of the reef community, the air-sea flux of CO2 driven by benthic community processes can exceed that due to increases in atmospheric CO2 (ocean acidification). We field test this model and examine the role of three key members of benthic reef communities in modifying the chemistry of the ocean source water: corals, macroalgae, and sand. Building on data from previous carbon flux studies along a reef-flat transect in Moorea (French Polynesia), we illustrate that the drawdown of total dissolved inorganic carbon (CT) due to photosynthesis and calcification of reef communities can exceed the draw down of total alkalinity (AT) due to calcification of corals and calcifying algae, leading to a net increase in aragonite saturation state (Ωa). We use the model to test how changes in atmospheric CO2 forcing and benthic community structure affect the overall calcification rates on the reef flat. Results show that between the preindustrial period and 1992, ocean acidification caused reef flat calcification rates to decline by an estimated 15%, but loss of coral cover caused calcification rates to decline by at least three times that amount. The results also show that the upstream–downstream patterns of carbonate chemistry were affected by the spatial patterns of benthic community structure. Changes in the ratio of photosynthesis to calcification can thus partially compensate for ocean acidification, at least on shallow reef flats. With no change in benthic community structure, however, ocean acidification depressed net calcification of the reef flat consistent with findings of previous studies.
Continue reading ‘Coral reefs modify their seawater carbon chemistry – case study from a barrier reef (Moorea, French Polynesia)’

Chemical modeling of marine trace metals: Effects of ocean acidification to marine ecosystem

Chemical thermodynamic model is introduced to evaluate ecological effects of ocean acidification, which is predicted from increasing ocean uptake of carbon dioxide. The chemical model contains metal complex formation with two types of dissolved organic ligands in seawater. Concentration responses of copper and iron species in seawater to pH decrease were simulated. Free copper ion concentration, whose level is closely related to toxicity to phytoplankton, shows no response to ocean acidification as buffering effects by organic ligands. Ocean acidification leads to increase of bio-available iron (organic iron complex) in seawater, which causes increasing marine primarily production and following export flux of carbon into ocean interior. Chemical model regarding bioactive trace metals suggests presence of a negative feedback to the rising atmospheric CO2.
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Modelling the effects of ‘coastal’ acidification on copper speciation

We present here a copper speciation model that accounts for the long-term (‘coastal-acidification’) and short-term (daily and seasonal variation) variability in water pH and water temperature. The developed model is applied to a sub-tropical estuary (Moreton Bay, Australia) at a one hundred year time scale so that outputs are consistent with climate change projections. The model predicts that the mean cupric ion concentration (Cu2+) in the estuary will increase by 115% over the next 100 years as a result of the projected decrease in pH and increase in water temperature. Through calibration, the estimated concentration of copper-complexing dissolved organic matter (DOM) in the estuary is found to be 22.5 nM. An increase in the concentration of Cu2+, which is the most toxic and bioavailable form of copper, has implications for ecosystem health and may have a negative effect on the detoxifying capacity of DOM. Models that provide a framework for coupling biological, chemical and physical processes are important for providing a holistic perspective of coastal systems, especially for better understanding a system within the context of climatic and non-climatic drivers.
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Volcanic vents give sneak peek at acidic oceans

The underwater volcanoes off a tiny Italian island are helping scientists peer into the future of a world altered by increasing amounts of carbon dioxide emitted into the air and absorbed into the oceans.

The waters just off the island of Ischia mirror the projected conditions of the Earth’s oceans at the beginning of the next century because the volcanic vents found there infuse the water with large helpings of carbon dioxide, or CO2, which turns seawater acidic.

Research has shown that the growing acidic conditions are harmful to some sea creatures — those that build their protective shells with calcium are increasingly prevented from doing so the more acidic waters become.

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Physical scientist on ocean acidification science

Department: Department Of Commerce
Agency: National Oceanic and Atmospheric Administration
Sub Agency: National Oceanic and Atmospheric Administration
Job Announcement Number: OAR-HQ-2011-0064

SALARY RANGE: $89,033.00 – $136,771.00 /year
OPEN PERIOD: Tuesday, September 27, 2011 to Wednesday, October 05, 2011
SERIES & GRADE: ZP-1301-04/04
POSITION INFORMATION: Competitive: Career/Career-Conditional Permanent Full-time
DUTY LOCATIONS: 1 vacancy(s) in one of the following locations: Silver Spring, MD

The National Oceanic and Atmospheric Administration’s (NOAA) Office of Oceanic and Atmospheric Research (OAR) is where science comes to life. Become part of a team that develops innovative ideas and technologies and collaborates with the many talented and dedicated people who work to solve the mysteries of the deepest oceans to the surface of the sun. Explore facets and trends of the earth’s environment that will influence the future. Become a part of the team that provides the nation with scientific information to thrive in an ever-changing world.

This position is under the National Oceanic and Atmospheric Administration’s (NOAA), Office of Oceanic and Atmospheric Research (OAR), Ocean Acidification Office located in Silver Spring, MD.
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Putting prey and predator into the CO2 equation – qualitative and quantitative effects of ocean acidification on predator–prey interactions

Little is known about the impact of ocean acidification on predator–prey dynamics. Herein, we examined the effect of carbon dioxide (CO2) on both prey and predator by letting one predatory reef fish interact for 24 h with eight small or large juvenile damselfishes from four congeneric species. Both prey and predator were exposed to control or elevated levels of CO2. Mortality rate and predator selectivity were compared across CO2 treatments, prey size and species. Small juveniles of all species sustained greater mortality at high CO2 levels, while large recruits were not affected. For large prey, the pattern of prey selectivity by predators was reversed under elevated CO2. Our results demonstrate both quantitative and qualitative consumptive effects of CO2 on small and larger damselfish recruits respectively, resulting from CO2-induced behavioural changes likely mediated by impaired neurological function. This study highlights the complexity of predicting the effects of climate change on coral reef ecosystems.
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Postdoctoral research fellowship in ocean biochemistry and ecosystems at University of Southampton, UK

Postdoctoral Research Fellowship in Ocean Acidification Impacts on Sea-Surface Biology, Biogeochemistry and Climate School of Ocean and Earth Science in University of Southampton, UK

Study Subject(s):Ocean Acidification Impacts on Sea-Surface Biology, Biogeochemistry and Climate
Course Level: Postdoctoral Research
Scholarship Provider: NERC
Scholarship can be taken at: UK

You should have a PhD in oceanography, marine chemistry, biogeochemistry or a related topic. Experience of multivariate statistical techniques such as cluster and correlation analysis, and a scientific background in carbonate chemistry are both highly desirable.You will have demonstrated the ability to write scientific outputs for publication, have good oral communication skills and be mathematically capable. A strong desire to work as part of a multi-institute interdisciplinary research team is essential. You will participate in 2 research cruises.
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Ocean acidification in the IPCC AR5 WG II

OUP book