Images of the Great Lakes (with captions in “notes” pane) Great Lakes Environmental Assessment and Mapping Project (GLEAM) 17 December 2012

Environmental stress mapped across the surface of the Great Lakes, based on the combined influence of 34 different environmental threats.  The map can be used to guide future restoration efforts. Image courtesy of University of Michigan.

Satellite view of the Great Lakes, captured by the NASA Aqua-MODIS satellite on August 28, 2010. Photo courtesy of NASA and taken by Jeff Schmaltz, MODIS Rapid Response Team at NASA Goddard Space Flight Center. Website source with more information: http://www.flickr.com/photos/gsfc/4968915002/

Boats at Grand Haven Marina in Michigan August 16, 2002, with invasive plants (purple loosestrife here) and shoreline development in the background. The Laurentian Great Lakes are valued for recreational boating and other ecosystem services, but they face dozens of environmental stressors. Photo courtesy of Michigan Sea Grant.

Fishing is a highly valued human benefit of the Great Lakes, but it also requires careful management to ensure that native populations stay abundant and maintain their role in the food web. This image shows commercial fishermen with a catch of lake whitefish. Photo courtesy of Michigan Sea Grant.

Invasive zebra mussels appeared in the Great Lakes in Lake St Invasive zebra mussels appeared in the Great Lakes in Lake St. Clair in 1986, followed by quagga mussels in 1989. Invasive mussel colonization has resulted in profound physical and chemical changes in the Great Lakes. Shown here are mussel shells washed up on a Great Lakes beach. Photo courtesy of Michigan Sea Grant.

The sea lamprey invaded Lake Ontario in the early 19th century and spread throughout the Great Lakes in the mid-20th century. The sea lamprey parasitizes several species of commercial and sport fishes including lake trout, lake whitefish, and stocked salmon. The Great Lakes Fishery Commission coordinates a sea lamprey control program to reduce sea lamprey population size. Photo by Ted Lawrence, courtesy of the Great Lakes Fishery Commission.

Common reed is a wetland plant that can grow up to 20 feet (6 meters) tall and forms dense stands that crowd out native plants, inhibit animal movement, serve as a poor quality food for animals, and slow decomposition. This photo from June 2007 was taken in Point Mouille Game Area on the shores of Lake Erie. Photo courtesy of Michigan Sea Grant.

Satellite view of Lake Erie, captured by the NASA Aqua-MODIS satellite on October 9, 2011. Rivers feeding into the lake wash pollutants like nutrients from agricultural and urban lands into the lake, one factor contributing to harmful algae blooms (light green swirls). We also see tan swirls, which are sediments being washed in from rivers entering the lakes. The open water is dark blue, and light blue (almost white) swirls are likely chalky sediments suspended from a recent storm. Image courtesy of NASA and taken by Jeff Schmaltz, MODIS Rapid Response Team at NASA Goddard Space Flight Center. Website source with more information: http://earthobservatory.nasa.gov/IOTD/view.php?id=76115

A child swims at Bay City Park along Lake Huron in Michigan with a coastal power plant nearby. The Great Lakes are valued for their beaches and other recreational areas, but they face dozens of environmental stressors. Photo courtesy of Dave Brenner.