ALGAL BLOOMS IN THE GREAT LAKES OF NORTH AMERICA

Climate change effects on major drivers of harmful algal blooms (HABs): best management practices and HAB severity

Composed mainly of tourism and travel industries, the Lake Erie economy is valued at $10 billion/year. Harmful algal blooms (HABs) recurring in the western basin and hypoxia in the central basin of Lake Erie, one of the Great Lakes in northern America, have had a detrimental impact on economy of the region. With the predicted increase in temperature and precipitation, future recurrences of HABs will likely get worse with the changing climate. Thus, it is vital to identify best management practices and estimate HABs occurrence severity despite these mitigations in order to maintain Lake Erie’s economy.

CASE STUDY DESCRIPTION

Issue to be addressed

The recurrence of harmful algal blooms (HABs) in the western basin of Lake Erie is mainly attributed to the increase in dissolved reactive phosphorus (DRP) loads to Lake Erie. The extent of the HABs in summer of 2011 and 2015 was also the largest in the last decade. There is a consensus among the researchers, government agencies, and stakeholders that this increase in DRP is mainly coming from the agricultural lands of the Lake Erie watersheds. While current efforts are geared toward achieving the 40% nutrient reduction set by the 2012 Great Lakes Water Quality Agreement (GLWQA) between the United States and Canada, the effects of climate change on these reduction strategies has not been fully understood. Thus, this case study will quantify the amount of nutrient exports and the corresponding algal bloom severity under different future climate scenarios and mitigation practices. The results will help inform and prepare better the stakeholders (e.g. farmers, government agencies (local, state, federal), policymakers, and non-governmental organizations (NGOs)) against the effects of climate change.

Decision support to client

We will  provide and discuss the results of the project with the client, the Toledo Metropolitan Area Council of Governments (TMACOG), comprised mainly of government agencies, private entities, and NGOs in northwest Ohio and southeast Michigan. We envisage that these stakeholders will use these results to develop contingency management plans in anticipation of the climate change effects on water quality and quantity at Lake Erie. Specifically, this project will identify effective practices that the client could implement to reduce nutrient exports (hence, HABs) despite the climate change effects.

Temporal and spatial scale

The average of twenty-year baseline and future projections (1981-2000, 2001-2017, 2020-2040, 2040-2060) of the selected CIIs will be provided and discussed with the client and stakeholders. Management and mitigation practices are usually implemented at the field (~10 hectares) to watershed level (>90 km2). The project will focus on the Maumee watershed, a major load contributor to Lake Erie.

Knowledge brokering

We have presented the objectives to the client and asked for their ranking of the CIIs according to their needs (see table 1). The client is looking forward to seeing the results of the study (e.g. the CIIs and water impacts). We plan to present the baseline results (1981-2000 and 2001-2017) by the end of spring 2018.

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National Center for Water Quality Research from Heidelberg University

Toledo Metropolitan Area Council of Governments (TMACOG) Watersheds Committee

Poster displayed at the Kick–Off meeting, 7/8 September 2017, Norrköping, Sweden