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Biogeochemical and ecological impacts of amphipod circoviruses in benthic habitats.

 Kalia Bistolas, Ian Hewson, Jim Watkins, Lars Rudstam (Funded by National Science Foundation)

Benthic amphipods are key indicators of ecosystem health in the Laurentian Great Lakes. Annual monitoring programs depict progressive and precipitous declines in populations of the dominant amphipod, Diporeia spp. in three of the four deep lakes between 1997 and 2018. The mechanism(s) responsible for Diporeia population decline remain unknown. A previous study identified several putative CRESS-DNA viruses associated with Diporeia. The current project corroborates these findings and indicates that CRESS-DNA viruses are common constituents of Diporeia nanobiomes from both Great Lakes and Finger Lakes populations. One previously identified viral genotype, LM29173, is prevalent and recurrent among Lake Michigan and Lake Huron Diporeia. While this viral genotype is more abundant in declining Diporeia populations, we found that the distribution of LM29173 is most closely associated with amphipod haplotype demographics (irrespective of the state of population decline). This makes it unlikely that this virus caused the Diporeia decline in the Great Lakes. Since little is known about the role of CRESS-DNA viruses in mediating the ecology, physiology, or mortality of crustaceans, we also surveyed the viruses more broadly across crustacean taxa. This has revealed many new viral types are present in crustaceans. Kalia Bistolas completed her PhD in 2019 and is now a postdoc in Oregon State continuing working on viral diseases, but now in marine systems.