Autotrophlc-Heterotrophic Community Metabolism Relationships of a Woodland Stream

Abstract

ABSTRACT Using an in situ chamber oxygen method at five first through third order stream riffle sites in Augusta Creek, Michigan, estimates of community metabolism were made on a monthly or seasonal basis (1973–1975). Net community productivity (NCP) ranged from −0.25 to 4.03 gO2m −2d−1, community respiration (CR) from 0.24 to 3.67 gO2m 2d1, and gross community productivity (GCP) from 0.09 to 5.35 gO2m −2d−1. The integrative parameters net daily metabolism (NDM) and ratio of GCP to 24 hour CR (P/R) ranged from −0.72 to 2.68 gO2m −2d−1 and 0.017 to 2.5, respectively and remained relatively constant at each site. Most parameters were consistently low and stable at first order sites, while autotrophic sites differed significantly. The first order sites were heterotrophic (P/R<1) with negative NDM. The meadow second order site was autotrophic with little capacity for export, illustrated by low NDM. Both third order sites (wooded and cleared) were autotrophic, but the cleared site had a higher NDM.