ISSN:
1573-515X
Keywords:
Arctic lake
;
carbon cycle
;
organic carbon budget
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract The organic carbon cycle of a shallow, tundra lake (mean depth 1.45 m) was followed for 5 weeks of the open water period by examining CO2 fluxes through benthic respiration and anaerobic decomposition, photosynthesis of benthic and phytoplankton communities and gas exchange at the air-water interface. Total photosynthesis (as consumption of carbon dioxide) was 37.5 mmole C m−2 d−1, 83% of which was benthic and macrophytic. By direct measurement benthic respiration exceeded benthic photosynthesis by 6.6 mmole C m−2 d−1. The lake lost 1.4 × 106 moles C in two weeks after ice melted by degassing C02, and 6.8 mmole C m−2 d−1 (1.5 × 106 moles) during the remainder of the open water period; 2.2 mmole C m2 d−1 of this was release Of CO2 stored in the sediments by cryoconcentration the previous winter. Anaerobic microbial decomposition was only 4% of the benthic aerobic respiration rate of 38 mmole C m−2 d−1. An annual budget estimate for the lake indicated that 50% of the carbon was produced by the benthic community, 20% by phytoplankton, and 30% was allochthonous material. The relative contribution of allochthonous input was in accordance with measurement of the δ15N of sedimented organic matter.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00003270
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