Seasonal Fluctuations of Zooplankton, Dissolved Oxygen, and Temperature in Lake Bemidji, Minnesota

Authors

Cody Coyle

Document Type

Article

Abstract

With the current influx of aquatic invasive species in Minnesota lakes, the status of zooplankton has become vital. Zooplankton are at the base of all food chains in aquatic ecosystems, ecosystems that vary greatly throughout a year’s time. The objectives of this study were to 1) track the location of zooplankton throughout the water column for an entire year, and 2) establish relationships between zooplankton location and specific water column characteristics. Zooplankton, dissolved oxygen, and temperature samples were collected bi-monthly at various depths at the deepest point in the southern basin of Lake Bemidji. Zooplankton were most abundant in the summer with densities ranging from 5-31 specimens per liter, with the highest densities being found in 3-8 meters of water. Densities during the winter ranged from 3-14 specimens per liter while being more homogenous in the water column. Dissolved oxygen remained high in the epilimnion throughout the year, peaking at 14.91 mg/L on 2 May 2017. A steady decline of dissolved oxygen as depth increased was observed in both winter and summer months with the lowest reading being 0.01 mg/L at 15 meters of depth on 15 September 2017. Temperature peaked in the epilimnion at 21.5 °C in the summer with it ranging from -0.5-3.4 °C in the winter. Hopefully these results will help fisheries managers and others interested in this field better understand the trends in zooplankton densities in lakes.

Publication Date

2018

Comments

Faculty Sponsor: Dr. Andrew W. Hafs, BSU Aquatic Biology Program.

Recommended Citation

Coyle, Cody, "Seasonal Fluctuations of Zooplankton, Dissolved Oxygen, and Temperature in Lake Bemidji, Minnesota" (2018). Journal of Earth and Life Science. 28.
https://pines.bemidjistate.edu/j-earth-life-sci/28