Fertilizing Oceans to Combat Climate Change: Research Guidelines

New: Joint statement from SCOR and GESAMP on Deliberate Nutrient Additions to the OceanThe Scientific Committee on Oceanic Research (SCOR)and GESAMP have released a joint statement regarding Deliberate Nutrient Additions to the Ocean. For any further questions regarding this statement, please refer to the contacts at the end of the document.The statement can be downloaded here.

GESAMP - GESAMP Presentation

The Oceans Finally Show Their Stripes -- Berardelli 2008 (428): 3 -- ScienceNOW

The Oceans Finally Show Their Stripes

By Phil Berardelli
ScienceNOW Daily News
28 April 2008

Researchers have assembled the most detailed picture of ocean currents ever produced, and in so doing they have revealed a vast array of striated currents that roughly parallel the equator. This new level of resolution should improve understanding of a wide variety of ocean-related phenomena.

Scientists have had a relatively easy time deciphering the big movements in the oceans. Major currents such as the Gulf Stream are easy to detect, for example, and climate researchers for some time have been tracking the Global Conveyor Belt--a giant underwater river that carries cold Arctic waters from the North Atlantic to the middle of the Pacific. More subtle ocean dynamics, known as weak structures, have remained largely invisible. Now an international team has assembled a high-resolution picture of the oceans using satellite radar altimeter and 20 years' worth of data collected from thousands of buoys in an ocean-surface network called the Global Drifter Program.

One of the most dramatic features revealed by the new data is a network of banded currents moving west to east and vice versa across all of the oceans at the snail's pace of about 30 meters an hour. "They're almost everywhere," says physical oceanographer and co-author Peter Niiler of the Scripps Institution of Oceanography in San Diego, California. "We've discovered many more weak structures than we thought," Niiler says. As Niiler, lead author Nikolai Maximenko of the University of Hawaii, Honolulu, and colleagues reported 24 April in Geophysical Research Letters, the currents in the northeastern Pacific, which move back and forth from the U.S. West Coast to Hawaii, could have as their source a current that loops up the California Coast and back south. The sources of stripes in other regions aren't yet known, but they all cross major ocean currents and behave more like waves rather than jets of water.

"Who would have thought the bands would be so ubiquitous," says geophysical fluid dynamicist Geoff Vallis of Princeton University. And physical oceanographer Terrence Joyce of Woods Hole Oceanographic Institution in Massachusetts says the bands are highly unusual, because they don't align with ocean currents that are defined by temperature or sea-surface height. The bands cross over the currents, he says, "yet they still persist. That's very curious, and the paper doesn't explain this curiosity."

The Oceans Finally Show Their Stripes -- Berardelli 2008 (428): 3 -- ScienceNOW

CHEMISTRY: Chloramine Complexities

Jake Yeston

Chloramine is a comparatively recent weapon in the ongoing battle to eliminate harmful microorganisms from drinking water supplies. Though its disinfecting properties are straightforward, the concomitant generation of ammonia as a byproduct can give rise to a complex web of downstream chemistry that remains an active area of study. One important reaction is microbial nitrification, or oxidation of the ammonia to nitrite and nitrate, which also lowers the water's pH by acid production. Zhang et al. have systematically explored the efficiency of nitrification in plumbing pipes of differing compositions--polyvinyl chloride (PVC), copper, lead, and brass--at various pH and phosphate levels. They found that relative to PVC, copper inhibited nitrifier growth, whereas lead enhanced it (probably through reductive cycling of nitrate back to ammonia via lead corrosion). Brass initially resisted nitrification activity, but then shifted its behavior after ~120 days, as the efficiency of copper leaching from the alloy diminished. A perhaps counterintuitive consequence of this reaction web is that PVC pipes may ultimately cause more metal ion leaching into the water stream than copper pipes, as the acid byproducts of nitrification degrade brass valves and faucets. -- JSY

Environ. Sci. Technol. 42, 10.1021/es702483d (2008).

Expanding Oxygen-Minimum Zones in the Tropical Oceans -- Stramma et al. 320 (5876): 655 -- Science

Expanding Oxygen-Minimum Zones in the Tropical Oceans

Lothar Stramma,^1* Gregory C. Johnson,² Janet Sprintall,³ Volker Mohrholz⁴

Oxygen-poor waters occupy large volumes of the intermediate-depth eastern tropical oceans. Oxygen-poor conditions have far-reaching impacts on ecosystems because important mobile macroorganisms avoid or cannot survive in hypoxic zones. Climate models predict declines in oceanic dissolved oxygen produced by global warming. We constructed 50-year time series of dissolved-oxygen concentration for select tropical oceanic regions by augmenting a historical database with recent measurements. These time series reveal vertical expansion of the intermediate-depth low-oxygen zones in the eastern tropical Atlantic and the equatorial Pacific during the past 50 years. The oxygen decrease in the 300- to 700-m layer is 0.09 to 0.34 micromoles per kilogram per year. Reduced oxygen levels may have dramatic consequences for ecosystems and coastal economies.

¹ Institut für Meereswissenschaften an der Universität Kiel (IFM-GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany.
² National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
³ Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, USA.
⁴ Baltic Sea Research Institute Warnemünde, Post Office Box 301161, 18112 Rostock, Germany.

^* To whom correspondence should be addressed. E-mail: lstramma@ifm-geomar.de

Expanding Oxygen-Minimum Zones in the Tropical Oceans -- Stramma et al. 320 (5876): 655 -- Science