Measuring spatial variation in secondary production and food quality using a common consumer approach in Lake Erie

Ecological Applications
Prepared in collaboration with National Oceanic and Atmospheric Administration
By: , and 

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Abstract

Lake Erie is a large lake straddling the border of the U.S. and Canada that has become increasingly eutrophic in recent years. Eutrophication is particularly focused in the shallow western basin. The western basin of Lake Erie is hydrodynamically similar to a large estuary, with riverine inputs from the Detroit and Maumee Rivers mixing together and creating gradients in chemical and physical conditions. This study was driven by two questions: How does secondary production and food quality for consumers vary across this large mixing zone? and Are there correlations between cyanobacterial abundance and secondary production or food quality for consumers? Measuring spatial and temporal variation in secondary production and food quality is difficult for a variety of logistical reasons, so here a common consumer approach was used. In a common consumer approach, individuals of a single species are raised under similar conditions until placed in the field across environmental gradients of interest. After some period of exposure, the response of that common consumer is measured to provide an index of spatial variation in conditions. Here, a freshwater mussel (Lampsilis siliquoidea) was deployed at 32 locations that spanned habitat types and a gradient in cyanobacterial abundance in the western basin of Lake Erie to measure spatial variation in growth (an index of secondary production) and fatty acid (FA) content (an index of food quality). We found secondary production was highest within the Maumee rivermouth and lowest in the open waters of the lake. Mussel tissues in the Maumee rivermouth also included more eicosapentaenoic and docosapentaenoic fatty acids (EPA and DPA, respectively), but fewer bacterial FAs, suggesting more algae at the base of the food web in the Maumee rivermouth compared to open lake sites. The satellite-derived estimate of cyanobacterial abundance was not correlated to secondary production, but was positively related to EPA and DPA content in the mussels, suggesting more of these important FAs in locations with more cyanobacteria. These results suggest that growth of secondary consumers and the availability of important fatty acids in the western basin are centered on the Maumee rivermouth.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Measuring spatial variation in secondary production and food quality using a common consumer approach in Lake Erie
Series title Ecological Applications
DOI 10.1890/15-0440
Volume 26
Issue 3
Year Published 2016
Language English
Publisher Ecological Society of America
Contributing office(s) Upper Midwest Environmental Sciences Center
Description 13 p.
First page 873
Last page 885
Country United States
Other Geospatial Lake Erie
Online Only (Y/N) N
Additional Online Files (Y/N) N