Annex 1: Nutrients

The purpose of this Annex is to address the issue of excess nutrients and reduce harmful and nuisance algal blooms.

There is an urgent need for a coordinated and strategic response to nutrient management issues in the Great Lakes, and in Lake Erie in particular. In the 1970s and 1980s, collaborative efforts to reduce phosphorus, were successful and lake conditions improved. By 1985, phosphorus loadings into the Great Lakes were at or below targets identified in the Canada-United States Great Lakes Water Quality Agreement. However, since the mid-1990s there has been a resurgence of algal blooms in Lake Erie and the nearshore areas of Lakes Huron and Ontario.

The reasons for the occurrence of algal blooms are now more complex than in past decades. The introduction of invasive species such as zebra and quagga mussels and round gobies the changes in agricultural production systems, increased urbanization, and climate change are all contributing factors. New solutions are required.

The Great Lakes are currently experiencing nutrient levels that impair human use and also result in harmful effects on ecosystem functions. This Annex recognizes that the continued environmental, social and economic health of the Great Lakes basin requires the effective and efficient management of nutrients from human activities. It addresses the need for improved understanding of nutrient issues while continuing to develop and promote actions to improve nutrient management and to reduce inputs from wastewater and stormwater.

Actions to understand and address issues related to nearshore water quality, aquatic ecosystem health, and harmful and nuisance algae will continue for all the Great Lakes. However, early efforts will be focussed on the nearshore and open waters of Lake Erie, and on priority watersheds. This focus on Lake Erie will address the lake at greatest risk and maximize returns on investment while generating scientific data and policy approaches that may be transferable to the other Great Lakes and potentially to aquatic ecosystems elsewhere in Canada.

There are a number of complementary initiatives that contribute to the goal of reducing harmful and nuisance algal blooms in the Great Lakes. These include federal and provincial investments in nutrient related research and monitoring; green infrastructure, wastewater technologies and facilities upgrades; and improvements in urban and rural land use and land management practices. Working with the Great Lakes community, this Annex strives towards the long-term goal of attaining the sustainable use of nutrients for the continued health and productivity of the Great Lakes ecosystem and economy. Specific commitments are provided to enhance the scientific understanding of nutrient dynamics, develop phosphorous targets and action plans, reduce nutrient inputs from urban and rural stormwater and wastewater, and increase the efficiency of agricultural nutrient use consistent with a healthy Great Lakes ecosystem and economy. Commitments in other Annexes including Lakewide Management, Climate Change Impacts and Promoting Innovation also contribute to reducing excessive nutrients.

Canada and Ontario will:

  1. (a) Improve knowledge and understanding of nutrient concentrations and loadings in Great Lakes tributary discharges, with an emphasis on Lake Erie tributaries;
  2. (b) Improve knowledge and understanding of phosphorus sources, the forms of phosphorus being discharged to the Great Lakes, and their seasonal characteristics; and
  3. (c) Enhance information on land use, soil and management practices relevant to excess phosphorus in the Great Lakes, with specific emphasis on Lakes Erie and Huron.

Ontario will:

  1. (d) Conduct sub-watershed and field scale research to support the ongoing development and implementation of new approaches and technologies for the reduction of phosphorus from agricultural sources;
  2. (e) Investigate the contribution of natural heritage features to reducing excess phosphorus from rural and agricultural landscapes; and
  3. (f) Support monitoring in priority watersheds to quantify land use – water quality relationships, including conducting event based monitoring where feasible.

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Canada will lead, with Ontario’s support:

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Canada will lead, with Ontario’s support:

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