Development of an integrated assessment of large lakes using towed in situ sensor technologies: Linking nearshore conditions with adjacent watersheds

Abstract

Coastal and nearshore regions of most large lakes have not been included in monitoring efforts in a regular, consistent and comprehensive fashion. To address this need, we have been developing a survey approach using towed in situ sensors to provide spatially-extensive mapping of nearshore conditions. Within the last decade, we have applied a strategy of towing along the coastline in all five US/Canadian Laurentian Great Lakes. We have developed confidence in the strategy's ability to assess the entire nearshore region comprehensively and efficiently. This article presents an overview of steps of the development, a selection of representative results, and our continuing evaluation of the approach. Findings to date demonstrate an ability to establish linkages between conditions in the nearshore and adjacent watersheds at a variety of spatial scales, including to the US basin-wide level. Results here highlight two plankton sensors (fluorometer for phytoplankton and [laser] optical plankton counter ([L]OPC)) for zooplankton. Results suggested a strong coherence between plankton parameters and a non-linear relationship of plankton metrics to human development of the landscape across the Great Lakes basin.

Keywords:

• Great Lakes
• coastal monitoring

Acknowledgements

We are indebted to Sam Miller, who captained a number of surveys and who has helped develop and maintain the instrument and data-stream arrays and performed some of the processing, since the start of this endeavor. Jon Van Alstine also has been a key in the field and in data processing. Matt Starry of SRA International has accomplished most of the GIS processing for us to establish tow tracks along bathymetric contours and to link tracks with adjoining landscape units. We enlisted many from the Mid-Continent Ecology Division of the EPA's Office of Research and Development who ably helped with towing surveys over the past decade, including Jill Scharold, John Morrice, Anne Cotter, Mike Knuth, Greg Peterson, Corlis West, Joel Hoffman, Mike Sierszen, Leroy Anderson, David Bolgrien, David Miller and Mario Picinich, as well as a number of summer students. We thank the EPA's Great Lakes National Program Office (GLNPO), specifically Paul Horvatin and Glenn Warren, for providing the R/V Lake Guardian as a platform for a substantial portion of the ∼6000 km stretch of Great lakes nearshore waters through which we have now trailed our tethered instrument array. GLNPO also provided funding for data processing and we have a partnership to assist with technology transfer to enable continued Great Lakes nearshore monitoring. Thanks to David Bolgrien and Mary Ann Starus for helpful reviews of the initial draft of this article and to anonymous reviews by the journal referees and its editing staff. This work was funded entirely by the USEPA. Any mention of trademarks or brand names does not imply endorsement by the USEPA. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the USEPA.