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A nitrite-oxidizing enzyme may work in reverse for some microbes in the Antarctic autumn. Marine microorganisms play a major role in cycling elements like carbon and nitrogen throughout the environment. In the nitrogen cycle, some microbes perform an especially important step: the oxidation of nitrite (NO2−) to nitrate (NO3−), the dominant form of biologically available nitrogen in the ocean. Now Kemeny et al. suggest that the enzyme that converts nitrite to nitrate sometimes works in revers
The Southern Ocean around Antarctica is active in deep ocean ventilation and thus important in the uptake of fossil fuel carbon dioxide and global warming heat. Prof. Daniel Sigman presents evidence that deep ocean ventilation by the Southern Ocean was slower during past ice ages and faster during warm interglacial periods. These findings raise possibilities that deep ocean ventilation by the Southern Ocean will accelerate into the global warming future, counter to most model-based expectation.
The Department of Geosciences and Princeton University congratulates Xingchen (Tony) Wang on successfully defending his Ph.D. thesis: "Nitrogen Isotopes in Scleractinian Corals: Modern Ocean Studies and Paleoceanographic Applications."
A new study finds that human activities are likely contributing far less nitrogen to the open ocean than many atmospheric models suggest. That's generally good news, but it also nullifies a potential side benefit to additional nitrogen, says Meredith Hastings, associate professor of Earth, environmental and planetary sciences at Brown University and one of the study's co-authors. (Co-author Prof. Daniel Sigman et al)