Tributary Influences on Nearshore Water Quality in Lake Superior's Chequamegon Bay

Session: 57. - Advances in Understanding Nearshore Ecosystems in Great Lakes and Connecting Channels

Matthew Hudson, Northland College, Mary Griggs Burke Center for Freshwater Innovation, [email protected]
Matthew Cooper, Northland College, Mary Griggs Burke Center for Freshwater Innovation, [email protected]
Randy Lehr, Northland College, Mary Griggs Burke Center for Freshwater Innovation, [email protected]
Christopher McNerney, Northland College, [email protected]

Abstract

Chequamegon Bay (CB) is one of the warmest, shallowest, most isolated, and southerly bays in Lake Superior; and is an ideal location to study effects of climate change and eutrophication on nearshore water quality. Since 2014, we have conducted an integrated sampling program to collect baseline data in CB, with the goal of understanding how nearshore water quality relates to physical processes and tributary loading to affect ecosystem processes. Our approach includes 1) maintaining a series of continuous stream discharge monitoring stations and developing estimates of suspended sediment and phosphorus loading to CB, 2) collecting semi-monthly water chemistry profiles, phosphorus, chlorophyll, suspended sediment, and plankton samples from 11-12 stations in CB, and 3) completing a ROMS hydrodynamic model for CB and adjacent Lake Superior nearshore. Results indicate that large storm events lead to episodic pulses of sediment and phosphorus to CB. We will report on expanded analyses of watershed loading and in-lake water chemistry datasets, with a particular focus on identifying linkages between tributary loading and CB water quality and identifying signals in our datasets that differentiate baseline and episodic, event-driven conditions that could assist with understanding how future climate and/or land use changes could affect ecosystem conditions in CB.

1. Keyword
sediment load

2. Keyword
Lake Superior

3. Keyword
water quality