Benthic Community Metabolism in Two Northern Mississippi Streams

Abstract

Seasonal estimates of metabolism were determined with closed, replicate, 12-liter recirculating chambers on an artificially constructed gravel bar in a seventh order stream, the Tombigbee River, and on a natural riffle in a fourth order stream, the Buttahatchie River. In the Tombigbee and Buttahatchie rivers, the reypettive ranges for metabolism parameters were as follows (in g 0 m d : gross community 2 primary productivity, 0.39 to 2.97 and 0.06 to 0.44; net community primary productivity, -0.72 to 2.38 and -0.50 to 0.11; community respiration, 0.60 to 6.00 and 0.24 to 1.04; net daily metabolism, -3.22 to 1.61 and -0.90 to -0.01; and ratios of gross community primary I productivity to 24 hour community respiration (P/R), 0.38 to 2.01 and 0.09 to 0.98. Stepwise multiple linear regression indicated that most of the variation in metabolism parameters was explained by temperature, detritus, substrate-level light, and total Kjeldahl nitrogen in the Buttahatchie River, and by turbidity, temperature, chlorophyll, and nitrate-nitrogen in the Tombigbee River. Both rivers were predominately heterotrophic. The Tombigbee River was autotrophic only in January, at which time an algal-based community existed. During all other sampling periods, both communities were dominated by bacteria and utilized allochthonous inputs.

Variability in benthic respiration in three southeastern Australian lowland rivers

“…Respiration at our sites was typically an order of magnitude less than in the lowland Spree River (Germany), where community respiration was estimated to be 8.1-21.3 g O 2 m À2 d À1 (Böhme, 1994; and Pusch, 2001). The average respiration across our sites was similar to that reported for some northern hemisphere streams (Hedin, 1990;Naimo et al, 1988), but was an order of magnitude less than a fourth-order Australian stream draining a eucalypt forest (Treadwell et al, 1997). The average community respiration at our sites was up to two orders of magnitude less than that occurring in blackwater rivers (Fuss and Smock, 1996;Meyer et al, 1997).…”

Effects of inorganic sedimentation and riparian clearing on benthic community metabolism in an agriculturally-disturbed stream

“…In contrast, the cobble site remained slightly autotrophic. The estimates of NCP and GCP for the two sand impacted sites were among the lowest photosynthesis values ever recorded for streams using chamber estimates (Bott et al, 1978;Busch & Fisher, 1981;Bott et al, 1985;Brown & King, 1987;Naimo et al, 1988;King & Cummins, 1989a). In contrast, estimates of NCP and GCP at the OCC site were relatively high when compared to values in the literature.…”

“…In contrast to chlorophyll a from the sand sites, OCC pigment densities tended to be high relative to many those reported for natural systems (Minshall et al, 1983;Naimo et al, 1988;Davies-Colley, 1992;Minshall et al, 1992). This may be due, in part, to the greater stability offered by cobble substrates (Tett et al, 1978).…”

Spatio-temporal variation of benthic metabolism in a large, regulated river

“…However, our CR rates were less than half of what has been reported by comparable studies (e.g., Naiman, 1983;Naimo & Layzer, 1988;Rier & King, 1996). Differences in CR could be linked to variations in methods between our study and previous studies.…”