pdf WQ7 April 2020 Update - Decreased Algae Density in Les Cheneaux Island Waters Attributed to Cooler Water Temperatures and Rising Lake Huron Levels

Author: R.A. Smith

Author Affiliation: LCWC

Journal: Unpublished Report April 2020



From 2013 through 2019 water levels in the Les Cheneaux Islands have risen 63 inches (160 cm). During the same period, aver- age water temperatures dropped 3.5o to 4.5 o Centigrade ( 8o Fahrenheit). It was expected that these shifts in conditions would result in a related downward shift in phosphorus concentrations that are monitored each summer as part of our water quality program. This was not the case, however. Phosphorus values appeared to change little. Neither did it make sense that, while phosphorus concentrations remained level, the algae population densities decreased. Phosphorus is a primary food source for algae and if the phosphorus levels remained level, then algae concentrations would have been expected to remain within a constant range as well. Algae populations measured were phytoplankton, the free-living plankton that are found dispersed in the water column. The following paper examines this apparent disconnect between the expected and the actual.


Sincere appreciation is expressed to several people involved during this lengthy study, they include:

  • Editors of this document: Bill Kurtz, Scott Myers and Ed
  • Sample analysis: Tim Veverica and staff at the Univ Mich Biol Station at Douglas
  • Sample collection: Scott Myers, Lynn Wolters, Neil Williams, Mark Clymer, Mike & Laurel Jellison, Fred and Joyce Moore, Barb Smith, Mary Baker, Dave Dunn.