Open AccessNon‐Redfield carbon and nitrogen cycling in the Arctic: Effects of ecosystem structure and dynamics
Author(s) -
Daly Kendra L.,
Wallace Douglas W. R.,
Smith Walker O.,
Skoog Annelie,
Lara Rubén,
Gosselin Michel,
Falck Eva,
Yager Patricia L.
Publication year - 1999
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1998jc900071
Subject(s) - photic zone , redfield ratio , zooplankton , carbon fibers , environmental chemistry , organic matter , particulates , autotroph , total organic carbon , environmental science , copepod , carbon cycle , dissolved organic carbon , ecosystem , phytoplankton , nutrient , oceanography , chemistry , ecology , biology , geology , crustacean , materials science , genetics , composite number , bacteria , composite material
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 μ M ) 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 μ M ) were approximately 25 to 45 μ M 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.