jsta / 2018_aslo

Does Lake and Stream Connectivity Control Phosphorus Retention in Lakes?

DOES LAKE AND STREAM CONNECTIVITY CONTROL PHOSPHORUS RETENTION IN LAKES?

Lake water residence time and depth are known to be strong predictors of phosphorus (P) retention. However, there is substantial variation in P retention among lakes with the same depth and residence time. One potential explanatory factor for this remaining variation is that connectivity among lakes as well as connectivity between lakes and nearby streams influences either lake P trapping or the quality of stream delivered P. Therefore, we examined the extent to which connectivity among lakes versus connectivity between lakes and streams contributes to differences in P retention among lakes. Specifically, we evaluated the effect of lake-based and stream-based connectivity metrics on P retention using a hierarchical parameterization of the Vollenweider equation. We compared Vollenweider’s k in lakes with high and low stream versus lake connectivity. We found that variation in k is more strongly associated with lake connectivity metrics compared to stream connectivity metrics. This result suggests that lake-associated processes, which likely control P trapping, play a larger role in determining P retention than stream-associated processes which may affect variation in the type of delivered P.

Slides and related materials will be archived at http://doi.org/ckpf prior to the conference.