In the field of ocean acidification, duties will include supporting ocean acidification related activities within the Ocean Carbon and Biogeochemistry Program (OCB) project office and contributing to analysis of the magnitude and impacts of ocean acidification on natural and human systems. The successful candidate will work with internal and external collaborators to assess current and future ocean acidification research needs, assist with national and international coordination efforts, organize and present information via the web on current research activities, publications, meetings, funding opportunities, government actions, and international activities, and develop education and outreach materials on ocean acidification. The position will also involve analyzing numerical models, field observations and socio-economic data and contributing to the presentation of the results in lectures and manuscripts.
Continue reading ‘Woods Hole Oceanographic Institution research associate opportunity’
Archive for October 12th, 2010
Contrary to some previous, highly publicized, reports, ocean acidification is not likely to worsen the hearing of whales and other animals, according to a Woods Hole Oceanographic Institution (WHOI) scientist who studies sound propagation in the ocean.
Tim Duda, of WHOI’s Applied Ocean Physics & Engineering Department, undertook a study in response to warnings that as the ocean becomes more acidic—due to elevated levels of atmospheric carbon dioxide (CO2)–noise from ships will be able to travel farther and possibly interfere with whales and other animals that rely on sound to navigate, communicate, and hunt.
Duda and WHOI scientists Ilya Udovydchenkov, Scott Doney, and Ivan Lima, along with colleagues at the Naval Postgraduate School, designed mathematical models of sound propagation in the oceans. Their models found that the increase would be, at most, 2 decibels by the year 2100—a negligible change compared with noise from natural events such as storms and large waves. Noise levels are predicted to change even less than this in higher-noise areas near sources such as shipping lanes, Duda said.
Continue reading ‘Listen up: Ocean acidification poses little threat to whales’ hearing’
Putting carbon dioxide in the ocean is a terrible way to deal with climate change. Maybe we should do it.
Nestled on the narrow neck of a rocky peninsula that juts into the Pacific Ocean, the Seto Marine Laboratory is one of Japan’s oldest facilities for studying the abundant fish, marine invertebrates and seaweeds that have sustained people here for centuries. These days, the resort hotels that line the coastline of Shirahama — the name means “white beach” — are a far more important lifeline for the region’s economy than fishing. But in the laboratory, amid a welter of bubbling tanks and clattering pumps, a marine biologist named Yoshihisa Shirayama and his staff and student researchers are trying to understand how aquatic creatures adapt to a habitat in rapid flux. To that end, he and his colleagues have built an infrastructure that mirrors a changing ocean; with a few swipes across a touch-screen control pad, he can adjust the concentration of carbon dioxide in tanks that hold sea urchin larvae.
Continue reading ‘Ocean carbon sequestration: The world’s best bad idea’
The water column distribution of carbonate system variables at the ESTOC site from 1995 to 2004 (update)Published 12 October 2010 Science Leave a Comment
The accelerated rate of increase in atmospheric carbon dioxide and the substantial fraction of anthropogenic CO2 emissions absorbed by the oceans are affecting the anthropocenic signatures of seawater. Long-term time series are a powerful tool for investigating any change in ocean bio-geochemistry and its effects on the carbon cycle. We have evaluated the ESTOC (European Station for Time series in the Ocean at the Canary islands) observations of measured pH (total scale at 25 °C) and total alkalinity plus computed total dissolved inorganic carbon concentration (CT) from 1995 to 2004 for surface and deep waters, by following all changes in response to increasing atmospheric carbon dioxide. The observed values for the surface partial pressure of CO2 from 1995 to 2008 were also taken into consideration. The data were treated to better understand the fundamental processes controlling vertical distributions in the Eastern North Atlantic Ocean and the accumulation of anthropogenic CO2, CANT. CT at constant salinity, NCT, increased at a rate of 0.85 μmol kg−1 yr−1 in the mixed layer, linked to an fCO2 increase of 1.7±0.7 μatm yr−1 in both the atmosphere and the ocean. Consequently, the mixed layer at ESTOC site has also become more acidic, −0.0017±0.0003 units yr−1, whereas the carbonate ion concentrations and CaCO3 saturation states have also decreased over time. NCT increases at a rate of 0.53, 0.49 and 0.40 μmol kg−1 yr−1 at 300, 600, and 1000 m, respectively. The general processes controlling the vertical variations of alkalinity and the inorganic carbon distribution were computed by considering the pre-formed values, the production/decomposition of organic matter and the formation/dissolution of carbonates. At 3000 m, 30% of the inorganic carbon production is related to the dissolution of calcium carbonate, increasing to 35% at 3685 m. The total column inventory of anthropogenic CO2 for the decade was 66±3 mol m−2. A model fitting indicated that the column inventory of CANT increased from 61.7 mol m−2 in the year 1994 to 70.2 mol m−2 in 2004. The ESTOC site is presented as a reference site to follow CANT changes in the Northeast Atlantic Sub-tropical gyre.
Continue reading ‘The water column distribution of carbonate system variables at the ESTOC site from 1995 to 2004 (update)’
Acousticians quiet warnings that sounds will travel farther
In 2008, a group of marine chemists raised a red flag: As the ocean becomes more acidic over the next century, they said, noise from ships will be able to travel farther and possibly interfere with whales and other animals that rely on sound to navigate, communicate, and hunt. The press ran with it. Even the reputable magazine Scientific American posted a blog entry titled, “Could ocean acidification deafen dolphins?”
But when Tim Duda, who studies sound propagation in the ocean at Woods Hole Oceanographic Institution (WHOI), read the same reports, he thought, “Time out, it’s not that simple!” He and colleagues decided to apply their acoustical know-how to investigate this potential increase in ocean noise.
Continue reading ‘Will more acidic oceans be noisier?’
Growing up in the temperate zone: Age, growth, calcification and carbonate mineralogy of Melicerita chathamensis (Bryozoa) in southern New ZealandPublished 12 October 2010 Science Leave a Comment
Tags: biological response, bryozoa
The cheilostome bryozoan Melicerita chathamensis from the continental shelf around southern New Zealand is unusual in having macroscopic annual growth checks. It thus presents an opportunity to examine annual variations in age, growth, calcification and carbonate mineralogy in a temperate bryozoan. Forty-one colonies dredged south of Snares Islands, New Zealand (47° 49.537′S, 166° 45.910′E, 166 m water depth, 2 February 2008) ranged from 2 to 9 years old and were up to 40 mm long. Segment length varied from 0.94 to 13.67 mm, with a mean growth rate of 5.27 mm y-1, whereas segment weight varied from 0.1 to 37 mg, with an average calcification rate of 9.2 mg y-1. Low-Mg calcite ranged from 0.8 to 3.6 wt% MgCO3, with a mean of 2.1 wt% MgCO3, whereas high-Mg calcite ranged from 6.6 wt% MgCO3 to 9.7 wt% MgCO3 with a mean of 8.1 wt% MgCO3. The well-studied polar M. obliqua, in contrast, grows more slowly over a much longer period and calcifies more rapidly, suggesting that polar bryozoans may be more effective at sequestering carbon than their temperate counterparts. The proportion of each mineral in skeletal segments generally varied with age, from almost entirely high-Mg calcite in the oldest segments to entirely low-Mg calcite at the growing tips, with a mean of 60.7% high Mg calcite. This unusual dual-calcite mineralogy appears to be analogous to some other cheilostomes which also produce a primary skeleton of low-Mg calcite but their secondary mineral is aragonite. Such bimineralic bryozoans, which are sophisticated mineralisers that exert a great deal of control over their skeletal composition, may be able to mineralise despite decreasing sea-water pH. Bimineral skeletal sediments, however, could be especially vulnerable to dissolution, as both aragonite and high-Mg calcite are more soluble than low-Mg calcite. Weakening of the skeleton by dissolution of secondary thickening could increase the likely effects of temperate abrasion and bioerosion.
Continue reading ‘Growing up in the temperate zone: Age, growth, calcification and carbonate mineralogy of Melicerita chathamensis (Bryozoa) in southern New Zealand’