Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-28
Total Federal Funds: $15,409 Total Non-Federal Funds: $30,817
Principal Investigators: Ted Ozersky
Abstract: Invasive dreissenid mussels (zebra and quagga mussels) are changing aquatic ecosystems throughout North America, with large and diverse effects on water quality, biological communities and productivity of invaded lakes and rivers. The ecological impacts of dreissenids are exerted through different mechanisms, including re-engineering of the cycling of ecologically important elements such as carbon (C) and the nutrients phosphorus (P) and nitrogen (N). While the effects of dreissenid excretion and soft-tissues on the cycling and storage of C, N and P have received some attention, our understanding of the role of dreissenid shell material in biogeochemical cycling is unfavorably out of proportion to its potential ecological importance. Shell may dominate the long-term effects of dreissenids on ecosystems because of its large quantity, long persistence in the ecosystem and incorporation of large quantities of ecologically important elements, including the nutrients N and P, as well as C and calcium (Ca). Understanding and predicting how dreissenid shell accumulation and dissolution affects invaded ecosystems is important for the informed management of water resources in the face of continuing dreissenid invasions and their interactions with other stressors, such as excessive nutrient loading, climate change and other invasive species. Three questions stand in the way of integrating the role of shell material into our understanding of how dreissenids change ecosystems. We do not know how much shell there is in different systems, what this shell is made from and what its long-term fate is. In the proposed project, graduate and undergraduate students will work with the PI to address these questions through surveys and experiments in dreissenid-infested lakes in Minnesota. We will measure mussel biomass and shell production and quantity in a set of lakes along a gradient of parameters such as size, invasion history and productivity. The elemental composition and fate of dreissenid shell material from different lakes will be determined using chemical analysis and shell dissolution experiments. Measurements of shell quantity, composition and fate will be combined with information about sampled lakes to produce predictive relationships between lake characteristics and the role of shell material in geochemistry of ecologically important elements such as C, Ca, N and P. The proposed work has the potential to contribute to more informed management of dreissenid-invaded waters in Minnesota and elsewhere and will provide training opportunities to graduate and undergraduate students at the University of Minnesota Duluth.