SUMMER DISTRIBUTION OF TOTAL SUSPENDED PARTICULATES IN THE WESTERN BASIN OF LAKE ERIE AND SANDUSKY BAY

We quantified the particle distribution and composition of surface waters in the western basin of Lake Erie and Sandusky Bay to better understand the factors that contribute to water quality. This will help us to ground truth satellite data collected from these shallow, eutrophic water bodies. This project consisted of undergraduates, graduate students and faculty advisors working in collaboration from the Departments of Geology and Biological Sciences at Kent State University. The research period consisted of 4 cruises on 6/11/07, 6/27/07, 7/29/07 and 8/14/07 at times corresponding to Landsat 5 overpasses. The sites consisted of 20 locations around the western basin and in Sandusky Bay. These locations were chosen to encompass many of the environments in Lake Erie ranging from deeper water, shallower bay waters and riverine discharges. During each cruise, we measured secchi depth, collected plankton tows, filtered surface water, and collected surface water samples for particle size analysis. Physical limnology and biological parameters were measured using a Hach Hydrolab DS5X Multiparameter Sonde, capable of measuring pressure, temperature, conductivity, DO, pH, ORP, Turbidity, Chl a, and Phycocyannin cell concentration. The water samples were analyzed in the lab using a Malvern Mastersizer 2000 Laser Particle Size analyzer to determine particle size. This data was correlated against ASD LabSpec Pro FR UV/VIS/nIR analyzer measurements on the GF/F filters. Principle component analysis of the particle size data indicate three peaks: a clay peak (~2.5um median grain size) associated with illite or smectite followed by two biogenic peaks corresponding to phytoplankton (~12um median particle size) and zooplankton (~75um median particle size). ASD reflectance data exhibit a clay peak at ~1910nm and biogenic peaks at 650nm and 685nm associated with plant pigment. The reflectance data is consistent on all 4 cruises, and the abundance of clays as well as biogenics are concentrated highest near the shore and associated with river discharge. Sites offshore show lower levels of turbidity which also decreased later in the year. The Malvern Mastersizer 2000 data was consistent with the ASD reflectance data and showed the same trend of increased particle abundance and size in the stations nearest the shore and in the bay.