Professor, Department of Biological Sciences

University of Notre Dame

Bio:

Gary E. Belovsky is a Professor in the Department of Biological Sciences at the University of Notre Dame. He earned a B.B.A. from Universtiy of Notre Dame, an M.F.S from Yale University, and a Ph.D from Harvard University. His post-doctoral appointments include Harvard Society of Fellows and University of Washington. He's held faculty positons in the School of Natural Resources & Departement of Biology at University of Michigan, the Department of Zoology at University of New South Wales (Austrailia), the Department of Fisheries & Wildlife at Utah State University, and as Gillen Director of the University of Notre Dame Environmental Research Center. Dr. Belovsky has conducted research at the National Bison Range in Montana since 1978 where he studies grassland, herbivore and predator ecology, especially for grasshoppers and birds, has been monitored and experimentally studied to understand ecosystem dynamics and the effects of climate change. Dr. Belovsky has worked on Great Salt Lake research since 1995. He works with UDWR’s Great Salt Lake Ecosystem Project, phytoplankton, microbialite, brine shrimp and brine fly larval biology have been experimentally studied and compared with lake observations. This has led to a synthesis of the lake’s pelagic ecosystem that was published in 2011, and development of a brine shrimp cyst harvesting model for UDWR management that was published in 2019. Since starting these studies, the ultimate goal was to develop a Great Salt Lake ecosystem model that could be employed to address lake management in the face of changing climate, water use, industrialization, agriculture and urbanization. Completion of the pelagic portion of the model is nearly complete.

Title: Why is salinity important to Great Salt Lake’s ecosystem?

Abstract: When we refer to hypersaline lakes, like Great Salt Lake (GSL), as extreme environments, the perception is that salinity drives biotic abundance. However, for biota adapted to living there, the environment is not stressful. Rather, the low salinity of freshwater is stressful, as is the high salinity of the salt-saturated north arm of the lake, where many GSL species are absent. Salinity changes in GSL arise as high lake levels (volume) dilutes salts and low levels concentrate salts. These changes in salinity impact phytoplankton and microbialites (primary producers), which in turn affect survival, growth and reproduction of brine shrimp and brine fly larvae (primary consumers) directly and through their food’s abundance (primary producers).

However, salinity is not the only thing changing with lake level. Nitrogen sources, that limit primary producers, which are food for primary consumers, are diluted and concentrated. Finally, lake level affects heating and cooling of the Lake, which affects primary producers and consumers. In turn, primary consumer abundance may affect their avian consumers. Therefore, attempting to attribute changes in lake salinity, as lake levels change, to ecological changes can be misleading, as availability of nitrogen sources and temperature also change.

Lake level’s simultaneous linkage to salinity, nitrogen and temperature makes it difficult to attribute observed GSL ecological changes to any one factor, as factors work in concert or opposition on each biotic element. Laboratory experiments varying factors (salinity, temperature, nitrogen sources, amount of food and type of food) independently for each primary producer and consumer are needed to disentangle effects, and my lab has conducted these. Experimental results are employed to construct a computer model to assess how lake level affects the GSL ecosystem, and attributes the relative importance of each factor. The model predicts very well GSL 2015-2020 observations, explaining 79 – 96% of the variation for different biotic elements, and indicates that nitrogen resources for primary production (types and amount of food for consumers) and temperature appear more important than salinity.

Regardless, changes in lake level are affecting the Great Salt Lake ecosystem’s health and economic value, and the model can help forecast these changes. A future complication is posed by anthropogenic climate change, because the model indicates that the importance of salinity increases as temperature increases.