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Nitrogen removal in marine environments: recent findings and future research challenges

Hulth, Stefan and Aller, Robert Curwood and Canfield, Donald E. and Dalsgaard, Tage and Engström, Pia and Gilbert, Franck and Sundbäck, Kristina and Thamdrup, Bo Nitrogen removal in marine environments: recent findings and future research challenges. (2005) Marine Chemistry, 94 (1-4). 125-145. ISSN 0304-4203

(Document in English)

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Official URL: http://dx.doi.org/10.1016/j.marchem.2004.07.013


Respiratory reduction of nitrate (denitrification) is recognized as the most important process converting biologically available (fixed) nitrogen to N2. In current N cycle models, a major proportion of global marine denitrification (50–70%) is assumed to take place on the sea floor, particularly in organic rich continental margin sediments. Recent observations indicate that present conceptual views of denitrification and pathways of nitrate reduction and N2 formation are incomplete. Alternative N cycle pathways, particularly in sediments, include anaerobic ammonium oxidation to nitrite, nitrate and N2 by Mn-oxides, and anaerobic ammonium oxidation coupled to nitrite reduction and subsequent N2 mobilization. The discovery of new links and feedback mechanisms between the redox cycles of, e.g., C, N, S, Mn and Fe casts doubt on the present general understanding of the global N cycle. Recent models of the oceanic N budget indicate that total inputs are significantly smaller than estimated fixed N removal. The occurrence of alternative N reaction pathways further exacerbates the apparent imbalance as they introduce additional routes of N removal. In this contribution, we give a brief historical background of the conceptual understanding of N cycling in marine ecosystems, emphasizing pathways of aerobic and anaerobic N mineralization in marine sediments, and the implications of recently recognized metabolic pathways for N removal in marine environments.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com/science/article/pii/S0304420304002439
HAL Id:hal-00780284
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Aarhus Universitet (DENMARK)
Other partners > Stony Brook University (USA)
Other partners > Syddansk Universitet (DENMARK)
Other partners > Göteborgs Universitet (SWEDEN)
Laboratory name:
Deposited On:17 Dec 2012 15:07

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