Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

A.M. Cvancara


Sediment cores were taken from Main Bay and Creel Bay of Devils Lake (in 1975 and 1976) and East Devils Lake (in 1978), within the Devils Lake basin, and from Red Willow Lake (in 1979), a control lake outside of the Devils Lake basin, northeastern North Dakota. The cores were sampled, for the recovery of the ostracods, at 10-cm intervals. Fifteen species of ostracods were present in the studied cores: 8 candonids, 1 cyclocyprid, 3 cyprids, and 3 limnocytherids. Two distinct faunas are recognized. The Devils Lake-East Devils Lake fauna consists of Candona lactea, C. rawsoni, Cyprinotus glaucus, Potamocypris smaragdina, Limnocythere (Limnocytherina) ceriotuberosa, and L. staplini. The Red Willow Lake fauna consists of Candona acutula, C. candida, C. caudata, C. decora, C, ohioensis, C. lactea, C. pronopa, C. rawsoni, Cypridopsis vidua, Cyclocypris ampla, and Limnocythere (Limnocytherina) itasca. Only two species are in common in the two faunas. Variations of diversity, similarity, and equitability indices, and abundance of species with depth are used to interpret major episodes of environmental disruption. The faunas do not increase in complexity with time. The Devils Lake-East Devils Lake fauna indicates that the lakes have remained saline with time, but episodes of greatly increased salinity or desiccation have occurred at several intervals. Using sedimentation rates determined by Callender (1968) for Main Bay, major disruptive events are interpreted at 7,000, 1,500, 1,200, and 900 years BP. Sed imentation rates have not been determined for the other cores. The Red Willow Lake fauna indicates that the lake has remained relatively fresh with time, but periods of environmental disruption have occurred. The changing environments through time of Main Bay of Devils Lake, as interpreted on the basis of ostracod distribution patterns, correlates only generally with interpretations based on diatom succession and geo chemical analysis of the sediments.

Included in

Geology Commons