Seasonal patterns in hydrochemical mixing in three Great Lakes rivermouth ecosystems

Journal of Great Lakes Research
By: , and 



Rivermouth ecosystems in the Laurentian Great Lakes represent complex hydrologic mixing zones where lake and river water combine to form biologically productive areas that are functionally similar to marine estuaries. As urban, industrial, shipping, and recreational centers, rivermouths are the focus of human interactions with the Great Lakes and, likewise, may represent critical habitat for larval fish and other biota. The hydrology and related geomorphology in these deltaic systems form the basis for ecosystem processes and wetland habitat structure but are poorly understood. To this end, a multidisciplinary team of scientists examined hydrogeomorphic structure and lake-tributary mixing in rivermouths using water chemistry, stable isotopes, and current profiling over a five-month period. Results showed that the maximum depth of the rivermouth ecosystem influenced mixing, with temperature-related, density-dependent wedging and layering that isolated lake water below river water occurring in deeper systems. The inherent size of the rivermouth ecosystem, local geomorphology, and human modifications such as shoreline armoring and dredging influenced mixing by altering the propensity for density differences to occur. The improved scientific understanding and framework for characterizing hydrogeomorphic processes in Great Lakes rivermouths across a disturbance gradient is useful for conservation, management, restoration, and protection of critical habitats needed by native species.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Seasonal patterns in hydrochemical mixing in three Great Lakes rivermouth ecosystems
Series title Journal of Great Lakes Research
DOI 10.1016/j.jglr.2019.03.009
Volume 45
Issue 3
Year Published 2019
Language English
Publisher Elsevier
Contributing office(s) Great Lakes Science Center, Upper Midwest Environmental Sciences Center, Wisconsin Water Science Center
Description 13 p.
First page 651
Last page 663
Country United States
State Michigan, Wisconsin
Other Geospatial Ford River, Lake Michigan, Manitowoc River, Pere Marquette River
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