Nutrients

Harmful algae blooms can produce cyanotoxins that are harmful to humans, pets, livestock, and ecosystem health. Harmful algae blooms are a frequent occurrence in the Great Lakes, particularly in Lake Erie and Lake Michigan at the mouths of the Maumee and Fox Rivers and are partially caused by an excess of nutrients such as nitrogen and phosphorous in the water column.

Nitrogen and phosphorus are plant essential nutrients that are currently in excess in many aquatic ecosystems due to runoff from urban and agricultural areas. In high amounts, these nutrients are detrimental to aquatic ecosystem health, because elevated nutrients promote excessive growth or “blooms” of algae and other nuisance species. Many species that cause blooms can produce toxins which are...

Nutrients lost from agricultural areas in watersheds of the Great Lakes cause harmful algal blooms and hypoxia in some areas of the Great Lakes. Substantial efforts are being made in these watersheds to reduce the amount of nutrients entering the streams and rivers; however, additional work is needed to further reduce nutrient loads to meet international water quality standards. Limited research...

Rivers have a natural capacity to improve water quality when they are connected to their natural floodplains and are not overloaded with sediment and nutrient runoff. Where rivers have been disconnected from their historical floodplains and channelized to eliminate backwater areas, increased flow and nutrient loads have contributed to local and downstream problems of excessive nutrient enrichment...

Rivermouth ecosystems, or freshwater estuaries, are the focus of human and wildlife interactions with the Great Lakes. They are highly valued as the region’s urban, industrial, shipping and recreational centers; and home to recreational harbors, wildlife viewing and production, beaches and urban riverfronts. Rivermouths are also both the mixing zones where nutrients from upstream watersheds are...

Biological production represents the total amount of living material (biomass) that was produced during a defined period of time. This production is important because some of it is used for food and some is valued for recreation, it is a direct measure of total ecosystem processes, and it sustains biological diversity. Production is a measure of energy flow, and is therefore a natural currency for...