Abiotic controls and temporal variability of river metabolism: multiyear analyses of Mississippi and Chattahoochee River data

• DOI: 10.1899/13-018.1
• Publication Date: 2013-08-27T13:37:15Z
• Authors: Walter K. Dodds; Allison M. Veach; Claire M. Ruffing; Danelle M. Larson; Jason L. Fischer; Katie H. Costigan
• Keywords: Seasonality

Whole-ecosystem metabolism is an important indicator of the role organic matter, C cycling, and trophic structure in rivers. Ecosystem well studied small streams, but less known about large We estimated daily whole-ecosystem over 2 y for 1 site each at Mississippi Chattahoochee Rivers USA to understand factors influencing temporal patterns ecosystem metabolism. rates gross primary production (GPP), community respiration (CR), net (NEP) with a curve-fitting approach publicly available discharge (Q), dissolved O2, temperature, photosynthetically active radiation (PAR) data. Models were run week-long blocks, power analyses suggested that should be established least once 10-wk period throughout year characterize annual accurately these analyzed weekly averaged periods Spearman rank correlation identify potential drivers path interactions among variables driving GPP, CR, NEP. Both rivers had overall negative NEP, River stronger seasonal trends. In River, CR was strongly positively correlated Q, which suggests variation availability allochthonous C. Chattahoochee, most whereas GPP negatively autochthonous processes water-column light attenuation played roles dynamics. Our results suggest heterotrophic time scales autotrophy can seasonally.