Lakes can play a large role in structuring the chemical and physical templates of streams, yet they often are overlooked when stream function is evaluated. We examined how lakes within stream networks affect organic matter decomposition. We used a cotton-strip assay to evaluate cellulose decomposition potential (CDP) as loss of cotton-strip tensile strength in streams upstream and downstream of 4 mountain lakes in a lake district in the Sawtooth Mountains, Idaho. In addition, we used this assay to determine decomposition potentials along a longitudinal gradient in 1 stream–lake network. Decomposition coefficients (k) were 43% greater in lake-outflow streams than lake-inflow streams. Temperature explained 65% of the variability in decomposition rates across lake inflows and outflows, and decomposition rates in inflow streams were highly correlated with mean daily temperature (r = 0.99). Conversely, decomposition rates in outflow stream were strongly correlated with total N/total P ratios (TN/TP; r = 0.94). When temperature ranges were small, as was observed across 4 lake outflows and along a longitudinal gradient, decomposition rates appeared to be driven by differences in nutrient availability, mainly TP and, to a lesser extent, TN. Together, these results demonstrate that although temperature is a primary driver of decomposition, when temperature is similar across locations, nutrient availability can drive decomposition rates. Our results indicate that lakes within fluvial networks can modify stream function by altering both temperature and nutrient availability.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.