My research program seeks to understand the structure and function of freshwater food webs and how non-native species influence ecological processes. My students work primarily with crustacean zooplankton and use a variety of approaches including paleolimnology, laboratory and field experiments, stable isotopes, and field monitoring in inland lakes and the Laurentian Great Lakes. Many of our questions are motivated by finding solutions to the management of aquatic invasive species. Two current projects include: 1) 'Characterizing spiny water flea impacts using sediment records' which is funded by the Minnesota Aquatic Invasive Species Research Center, University of Minnesota; and 2) 'What gear on your boat is most likely to spread spiny water flea?' which is funded by the Aquatic Invasive Species Prevention Program, St. Louis County, Minnesota.
Bythotrephes longimanus (aka, spiny water flea, pictured below) has been a model organism for my research program. This invasive species invaded North America in the late 1900s, most likely in the ballast water of transoceanic ships. Learn more about spiny water flea, our recent projects, and my Lake Ecology class by accessing the following links:
Pawlowski, MB, Branstrator, DK, and Hrabik, TR. 2018. Major shift in the phenology of crustacean biomass in western Lake Superior associated with temperature anomaly. Journal of Great Lakes Research 44: 788-797.
Aliff, MN, Reavie, ED, TenEyck, MC, Branstrator, DK, Schwerdt, T, Cangelosi, AA, and Cai, M. 2018. Evaluation of a method for ballast water risk-release assessment using a protist surrogate. Hydrobiologia 817: 11-22.
Pawlowski, MB, DK Branstrator, TR Hrabik, and RW Sterner. 2017. Changes in the cladoceran community of Lake Superior and the role of Bythotrephes longimanus. Journal of Great Lakes Research 43: 1011-1110.
Branstrator, DK, AE Beranek, ME Brown, LE Hembre, and DR Engstrom. 2017. Colonization dynamics of the invasive predatory cladoceran, Bythotrephes longimanus, inferred from sediment records. Limnology and Oceanography 62: 1096-1110.
Sorensen, ML, and DK Branstrator. 2017. The North American invasive zooplanktivore Bythotrephes longimanus is less hypoxia-tolerant than the native Leptodora kindtii. Canadian Journal of Fisheries and Aquatic Sciences 74: 824-832.
Current Graduate Students
Megan Corum, (MS in Water Resources Science)
Nichole DeWeese (MS in Water Resources Science). ‘Characterizing spiny water flea impacts in Lake Mille Lacs and Lake Kabetogama using sediment records.’
Recent Graduate Students
Ian Harding (MS in Integrated Biosciences, 2017 graduate). ‘Growth and predatory demand of cisco (Coregonus artedi) in Western Lake Superior.’ Co-advised with T. Hrabik.
Matthew Pawlowski (MS in Integrated Biosciences, 2016 graduate). ‘Changes in the zooplankton community of Lake Superior and the implications of climate change and Bythotrephes longimanus.’ Co-advised with T. Hrabik.
Michael Sorensen (MS in Water Resources Science, 2015 graduate). ‘Hypoxia tolerance of the invasive zooplankton Bythotrephes longimanus and the native zooplankton Leptodora kindtii.’
Matthew TenEyck (PhD in Water Resources Science, 2015 graduate). ‘Defining the risk-release relationship of Daphnia magna, a non-native aquatic species in the environment of the Duluth-Superior Harbor.
Samantha Oliver (MS in Integrated Biosciences, 2012 graduate). ‘Nutrient regeneration by the zooplankton community in the deep chlorophyll layer of Lake Superior.’ Co-advised with T. Hrabik.
Ashley Beranek (MS in Integrated Biosciences, 2012 graduate). ‘An assessment of the long-term phenology and impact of Bythotrephes longimanus in Island Lake Reservoir, Minnesota, using sediment records.