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Ongoing Project: Biogeochemical and ecological impacts of amphipod circoviruses in benthic habitats.

Chris Hotaling with interns Iris Lin, Eliza Bonner and Catherine Louie at CBFS Open House Kalia Bistolas, Ian Hewson, Elliot Jackson, and Lars Rudstam (Funding from the National Science Foundation) 

Benthic amphipods serve as keystone species in the Laurentian Great Lakes, mediating functional and structural diversity in profundal communities by contributing to net detritivory, herbivory, and sediment bioturbation. Long-term, lake wide annual monitoring programs depict progressive and severe (up to 90%) declines in populations of the dominant amphipod, Diporeia spp. between 1997- 2015. The causative factors implicated in Diporeia decline remain unknown. However, previous metaviromic studies identified a well-represented CRESS-DNA virus associated with Diporeia from four of the five Great Lakes, excluding Lake Superior. Prevalence, load, and persistence of this single putative circovirus (LM29173) largely coincide with the severity of Diporeia decline in independent populations. This study builds upon assessments of circoviral prevalence and load from 2013, and identifies LM29173 as a persistent constituent of the Diporeia nanobiome over a multi-year sampling period. Furthermore, comparative analysis of Diporeia metaviromes from independent sampling sites in lakes with varying benthic profiles reveal several distinct patterns of viral consortia. While it is unclear if circoviruses are directly deleterious to amphipod hosts, it is apparent that CRESS-DNA sequence elements sharing similar features to LM29173 are ubiquitous in amphipod-associated metaviromes. In the upcoming year, this project actively seeks to determine if these circoviruses mediate the nutritional quality of Diporeia spp. or alter benthic biogeochemical cycling.