Non-Redfield carbon and nitrogen cycling in the Arctic: Effects of ecosystem structure and dynamics.

Daly, K.L., Wallace, Douglas W.R., Smith, W.O., Skoog, A., Lara, R., Gosselin, M., Falck, E. and Yager, P. (2000) Non-Redfield carbon and nitrogen cycling in the Arctic: Effects of ecosystem structure and dynamics. Open Access Journal of Geophysical Research: Oceans, 104 (C2). pp. 3185-3199. DOI 10.1029/1998JC900071.

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Abstract

The C:N ratio is a critical parameter used in both global ocean carbon models and field studies to understand carbon and nutrient cycling as well as to estimate exported carbon from the euphotic zone. The so-called Redfield ratio (C:N = 6.6 by atoms) [Redfield et al., 1963] is widely used for such calculations. Here we present data from the NE Greenland continental shelf that show that most of the C:N ratios for particulate (autotrophic and heterotrophic) and dissolved pools and rates of transformation among them exceed Redfield proportions from June to August, owing to species composition, size, and biological interactions. The ecosystem components that likely comprised sinking particles and had relatively high C:N ratios (geometric means) included (1) the particulate organic matter (C:N = 8.9) dominated by nutrient-deficient diatoms, resulting from low initial nitrate concentrations (approximately 4 μM) in Arctic surface waters; (2) the dominant zooplankton, herbivorous copepods (C:N = 9.6), having lipid storage typical of Arctic copepods; and (3) copepod fecal pellets (C:N = 33.2). Relatively high dissolved organic carbon concentrations (median 105 μM) were approximately 25 to 45 μM higher than reported for other systems and may be broadly characteristic of Arctic waters. A carbon-rich dissolved organic carbon pool also was generated during summer. Since the magnitude of carbon and nitrogen uncoupling in the surface mixed layer appeared to be greater than in other regions and occurred throughout the productive season, the C:N ratio of particulate organic matter may be a better conversion factor than the Redfield ratio to estimate carbon export for broad application in northern high-latitude systems.

Document Type: Article
Keywords: Aerosols
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
AWI
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/1998JC900071
ISSN: 2169-9275
Expeditions/Models/Experiments:
Date Deposited: 18 Feb 2008 17:24
Last Modified: 24 Nov 2017 12:36
URI: http://oceanrep.geomar.de/id/eprint/325

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