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Modeling the dynamics of metabolism in montane streams using continuous dissolved oxygen measurements
Author(s) -
Birkel Christian,
Soulsby Chris,
Malcolm Iain,
Tetzlaff Doerthe
Publication year - 2013
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/wrcr.20409
Subject(s) - moorland , environmental science , ecosystem , hydrology (agriculture) , streams , atmospheric sciences , riparian zone , ecosystem respiration , productivity , primary production , ecology , biology , geology , computer network , geotechnical engineering , computer science , macroeconomics , habitat , economics
We inferred in‐stream ecosystem processes in terms of photosynthetic productivity (P), system respiration (R), and reaeration capacity (RC) from a five parameter numerical oxygen mass balance model driven by radiation, stream and air temperature, and stream depth. This was calibrated to high‐resolution (15 min), long‐term (2.5 years) dissolved oxygen (DO) time series for moorland and forest reaches of a third‐order montane stream in Scotland. The model was multicriteria calibrated to continuous 24 h periods within the time series to identify behavioral simulations representative of ecosystem functioning. Results were evaluated using a seasonal regional sensitivity analysis and a colinearity index for parameter sensitivity. This showed that >95 % of the behavioral models for the moorland and forest sites were identifiable and able to infer in‐stream processes from the DO time series for around 40% and 32% of the time period, respectively. Monthly P/R ratios <1 indicate a heterotrophic system with both sites exhibiting similar temporal patterns; with a maximum in February and a second peak during summer months. However, the estimated net ecosystem productivity suggests that the moorland reach without riparian tree cover is likely to be a much larger source of carbon to the atmosphere (122 mmol C m −2 d −1 ) compared to the forested reach (64 mmol C m −2 d −1 ). We conclude that such process‐based oxygen mass balance models may be transferable tools for investigating other systems; specifically, well‐oxygenated upland channels with high hydraulic roughness and lacking reaeration measurements.