Ecosystem Metabolism and Turnover of Organic Carbon along a Blackwater River Continuum

作者：Judy L. Meyer, Rick T. Edwards · 发表于：Ecology · 年份：1990 · DOI：10.2307/1940321 · 被引用次数：157 · 研究领域：Fish Ecology and Management Studies、Soil and Water Nutrient Dynamics、Freshwater macroinvertebrate diversity and ecology

Variation in ecosystem metabolism and organic carbon turnover length was examined in the Ogeechee River (Georgia, USA) basin, a sixth—order blackwater river, to determine if the patterns observed in other rivers are also seen along a river continuum characterized by warm water temperatures, low stream gradient, extensive riparian swamps, and tea—colored water. The study was in two parts: an intensive study of seasonal variation in metabolism and organic carbon turnover length at a fourth—order site, which can be compared with an earlier study at a sixth—order site, and a study of the variation in system metabolism at five second— through sixth—order sites along the continuum. Metabolism varied seasonally at the fourth—order site that was studied most intensively; mean gross primary production (GPP, measured as O2) was 0.8 g°m—2°d—1 and mean community respiration (CR, also measured as O2) was 4.1 g°m—2°d—1. The community production/respiration ratio (P/R) ranged from 0.02 to 0.4 with an annual mean of 0.2. This is clearly a heterotrophic stream reach, where high rates of community respiration are supported by inputs of organic matter from extensive riparian swamps. Mean annual organ carbon turnover length at the fourth—order site was 570 km, although on most dates the length was much less, with a median of 114 km. Turnover lengths are significantly less than those at the sixth—order site, but much greater than observed in other rivers of similar size, probably because most of ...