Understanding the Drivers of Lake Ontario Nearshore Algae Blooms: Can Models Get Us Any Closer?

Session: State of Lake Ontario: 2003-2018 CSMI Overview (2)

James Pauer, USEPA/ORD Mid-Continent Ecology Division, [email protected]
Wilson Melendez, General Dynamics Information Technology, [email protected]
Mary Moffett, USEPA/ORD Mid-Continent Ecology Division, [email protected]
Tom Hollenhorst, EPA Mid Continent Ecology Division, [email protected]
Terry Brown, USEPA, [email protected]
Dustin Woodruff, USEPA/ORD Mid-Continent Ecology Division, [email protected]

Abstract

As part of the 2018 Cooperative Science and Monitoring Initiatives (CSMI), several sampling and research studies were undertaken to address ecological concerns in Lake Ontario.  One such concern is persistent nuisance algae in the nearshore.  Phosphorus is an important driver of algae growth such as for Cladophora, although the mechanism is not fully understood. It is also unclear what the major sources of phosphorus are. Is it inter-basin loads (Lake Erie via the Niagara River) or intra-basin loads (Lake Ontario tributaries)?  Mathematical models can be useful to address these issues in large complex systems such as the Great lakes where several drivers are responsible for excessive algal growth. We developed a simple biogeochemical model to describe and predict phosphorus and resulting algal concentration at several locations in the southern shore of Lake Ontario. The goal is to combine observations with model results to determine the fate and transport of nutrients and algae in the lake. Here we show initial results, and discuss challenges and next steps.