The organic carbon budget of a shallow arctic tundra lake on the Tuktoyaktuk Peninsula,N.W.T., Canada |
| |
Authors: | P S Ramlal R H Hesslein R E Hecky E J Fee J W M Rudd S J Guildford |
| |
Institution: | (1) Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2;(2) Department of Fisheries and Oceans, Freshwater Institute, Central and Arctic Region, 501 University Crescent, Winnipeg, Manitoba, Canada, R3T 2N6;(3) Present address: 605 Townsend Avenue, Winnipeg, Canada, MB R3T 2V3 |
| |
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 15N of sedimented organic matter. |
| |
Keywords: | Arctic lake carbon cycle organic carbon budget |
本文献已被 SpringerLink 等数据库收录! |
|