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Full-Text Articles in Life Sciences

Bottom-Up Control Of Parasites, David S. Johnson, Richard Heard Oct 2017

Bottom-Up Control Of Parasites, David S. Johnson, Richard Heard

VIMS Articles

Parasitism is a fundamental ecological interaction. Yet we understand relatively little about the ecological role of parasites compared to the role of free-living organisms. Bottom-up theory predicts that resource enhancement will increase the abundance and biomass of free-living organisms. Similarly, parasite abundance and biomass should increase in an ecosystem with resource enhancement. We tested this hypothesis in a landscape-level experiment in which salt marshes (60,000 m2 each) received elevated nutrient concentrations via flooding tidal waters for 11 yr to mimic eutrophication. Nutrient enrichment elevated the densities of the talitrid amphipod, Orchestia grillus, and the density and biomass of its …


Transmission Routes Maintaining A Viral Pathogen Of Steelhead Trout Within A Complex Multi-Host Assemblage, Rachel Breyta, Ilana Brito, Paige Ferguson, Gael Kurath, Kerry Naish, Maureen Purcell, Ar Wargo, Shannon Ladeau Jan 2017

Transmission Routes Maintaining A Viral Pathogen Of Steelhead Trout Within A Complex Multi-Host Assemblage, Rachel Breyta, Ilana Brito, Paige Ferguson, Gael Kurath, Kerry Naish, Maureen Purcell, Ar Wargo, Shannon Ladeau

VIMS Articles

This is the first comprehensive region wide, spatially explicit epidemiologic analysis of surveillance data of the aquatic viral pathogen infectious hematopoietic necrosis virus (IHNV) infecting native salmonid fish. The pathogen has been documented in the freshwater ecosystem of the Pacific Northwest of North America since the 1950s, and the current report describes the disease ecology of IHNV during 2000-2012. Prevalence of IHNV infection in monitored salmonid host cohorts ranged from 8% to 30%, with the highest levels observed in juvenile steelhead trout. The spatial distribution of all IHNV-infected cohorts was concentrated in two sub-regions of the study area, where historic …