AbstractPlankton samples were collected from June through October, 1970, at 5, 10, 15, and 18 m stations on transects extending into Indiana waters of Lake Michigan from Michigan City, Burns Ditch, and Gary.Bosmina longirostris, Daphnia retrocurva, and Cyclops bicuspidatus thomasi were the three dominant crustacean zooplankters in Indiana waters of Lake Michigan. Each species made up more than 10% of the total crustacean zooplankton community.The rotifer community was dominated by Polyarthra vulgaris. Other numerous rotifers included Keratella cochlearis, Synchaeta sp., and Kellicotia lonqispina.There were few consistent differences between the three transects, but, as station depth increased to 18 m, the population dynamics on the three transects tended to become more similar.In general the zooplankton community structure was made up of small microfiltrators with few macrofiltrators or predacious zooplankton present.The dominance of the microfiltrators, small size of Daphnia retrocurva sampled, seasonally late appearance of larger zooplankters, skewed sex ratios of Diaptomus, and increased numbers of zooplankton in general may all be the result of heavy alewife predation on large zooplankton forms.The dominance of less effective microfilter feeding zooplankton and the continued increase of nutrient levels in southern Lake Michigan may be combining to effect an increase in the eutrophication rate in the shallow Indiana waters of Lake Michigan.Ball State UniversityMuncie, IN 47306
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/180598 |
| Date | 03 June 2011 |
| Creators | Johnson, David L. |
| Contributors | McComish, Thomas S. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | vii, 129 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
| Coverage | n-us-in |
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