Department Chair

Alexander Y. Karatayev, Ph.D., Director of the Great Lakes Center

Date of Award

5-2020

Access Control

Open Access

Degree Name

Great Lakes Ecosystem Science

Department

Great Lakes Center

Advisor

Lyubov E. Burlakova

First Reader

Lyubov E. Burlakova, Ph.D., Senior Research Scientist, Thesis Advisor

Second Reader

Alexander Y. Karatayev, Ph.D., Director of the Great Lakes Center

Third Reader

Robert J. Warren II, Ph.D., Associate Professor of Biology

Abstract

Non-native invasive Dreissena mussels have altered the flow of energy in numerous freshwater systems by diverting nutrients from pelagic to littoral benthic food-webs, thus reducing primary production available to deep offshore benthos. Though the effect of the nearshore-dwelling Dreissena polymorpha (zebra mussel) on benthos has been studied thoroughly, little is known about the deep, offshore impacts of Dreissena rostriformis bugensis (quagga mussel). In the last two decades, quagga mussels have displaced zebra mussels in shallow Great Lakes regions and colonized previously uninhabited offshore lake regions. It is likely that the spread of quagga mussels into deep profundal areas has resulted in new interactions with offshore benthic communities. If there are positive interactions present, I expect positive correlations between quagga mussel and total non-dreissenid benthos and for taxonomic structures to be affected by Dreissena. Here, I investigate whether the positive impacts of quagga mussels on benthic communities previously observed in the nearshore benthos also occur in offshore benthos due to the recent quagga mussel colonization. I also investigate changes in nearshore and offshore benthic community composition in the presence and absence of quagga mussels. Benthic survey data collected under the Cooperative Science and Monitoring Initiative from Lake Michigan in 2015 and Lake Huron in 2017 were used in this study. Increased Dreissena abundance correlated with total non-dreissenid benthos regardless of depth and taxonomic structures of benthic communities change with depth and appear to be affected by dreissenid presence.

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