Geology topics

Justin A. Saarinen

Publications and source records attributed to Justin A. Saarinen.

4 recordsLinked to original sources

USGS2026

Geospatial data identify potentially restorable coastal wetland habitats in the Laurentian Great Lakes

Identifying areas with high restoration potential can guide investment and support management of coastal wetland habitats in the Laurentian Great Lakes. Restoration is a priority in the region since extensive degradation and alteration from anthropogenic activities reduced coastal wetlands to only a small fraction of historical extent. Our study evaluated the likelihood of coastal wetland restoration success using multi-criteria geospatial modeling in six restoration assessments focused on the U.S. portion of the Great Lakes coastline. We incorporated parameters into our model that positively influenced restoration potential, such as hydroperiod, wetland soil types, surface water flow networks, and conservation and recreation status of the land. Alternatively, factors that negatively influenced restoration potential were the proportion of impervious surfaces and other important human land uses of permeable soils. The resulting composite restoration index and online interfaces provide valuable decision-support tools for ecosystem managers. The modeled amount of restorable coastal wetland habitat and the characteristics of areas identified as restorable varied among the six restoration assessments, with the highest restoration index values occurring predominantly in low-elevation areas with frequent inundation that were near flowlines hydrologically connected to the Great Lakes. Conversely, areas with a greater proportion of impervious surfaces and anthropogenic land uses (e.g., golf courses) received low restoration index values. Our analysis highlights the heterogeneity of coastal wetland restoration potential throughout the Great Lakes, as well as the need for careful consideration of natural and anthropogenic land use factors to execute successful coastal wetland restoration.

Great Lakes↗

USGS2020

Spatial epidemiological patterns suggest mechanisms of land-sea transmission for Sarcocystis neurona in a coastal marine mammal

Sarcocystis neurona was recognised as an important cause of mortality in southern sea otters (Enhydra lutris nereis) after an outbreak in April 2004 and has since been detected in many marine mammal species in the Northeast Pacific Ocean. Risk of S. neurona exposure in sea otters is associated with consumption of clams and soft-sediment prey and is temporally associated with runoff events. We examined the spatial distribution of S. neurona exposure risk based on serum antibody testing and assessed risk factors for exposure in animals from California, Washington, British Columbia and Alaska. Significant spatial clustering of seropositive animals was observed in California and Washington, compared with British Columbia and Alaska. Adult males were at greatest risk for exposure to S. neurona, and there were strong associations with terrestrial features (wetlands, cropland, high human housing-unit density). In California, habitats containing soft sediment exhibited greater risk than hard substrate or kelp beds. Consuming a diet rich in clams was also associated with increased exposure risk. These findings suggest a transmission pathway analogous to that described for Toxoplasma gondii, with infectious stages traveling in freshwater runoff and being concentrated in particular locations by marine habitat features, ocean physical processes, and invertebrate bioconcentration.

California, Washington, British Columbia, Alaska↗

USGS2018

Defining the risk landscape in the context of pathogen pollution: Toxoplasma gondii in sea otters along the Pacific Rim

Pathogens entering the marine environment as pollutants exhibit a spatial signature driven by their transport mechanisms. The sea otter ( Enhydra lutris ), a marine animal which lives much of its life within sight of land, presents a unique opportunity to understand land–sea pathogen transmission. Using a dataset on Toxoplasma gondii prevalence across sea otter range from Alaska to California, we found that the dominant drivers of infection risk vary depending upon the spatial scale of analysis. At the population level, regions with high T. gondii prevalence had higher human population density and a greater proportion of human-dominated land uses, suggesting a strong role for population density of the felid definitive host of this parasite. This relationship persisted when a subset of data were analysed at the individual level: large-scale patterns in sea otter T. gondii infection prevalence were largely explained by individual exposure to areas of high human housing unit density, and other landscape features associated with anthropogenic land use, such as impervious surfaces and cropping land. These results contrast with the small-scale, within-region analysis, in which age, sex and prey choice accounted for most of the variation in infection risk, and terrestrial environmental features provided little variation to help in explaining observed patterns. These results underscore the importance of spatial scale in study design when quantifying both individual-level risk factors and landscape-scale variation in infection risk.

California↗

USGS2014

Effects of wildfire on sea otter (Enhydra lutris) gene transcript profiles

Wildfires have been shown to impact terrestrial species over a range of temporal scales. Little is known, however, about the more subtle toxicological effects of wildfires, particularly in downstream marine or downwind locations from the wildfire perimeter. These down-current effects may be just as substantial as those effects within the perimeter. We used gene transcription technology, a sensitive indicator of immunological perturbation, to study the effects of the 2008 Basin Complex Fire on the California coast on a sentinel marine species, the sea otter ( Enhydra lutris ). We captured sea otters in 2008 (3 mo after the Basin Complex Fire was controlled) and 2009 (15 mo after the Basin Complex Fire was controlled) in the adjacent nearshore environment near Big Sur, California. Gene responses were distinctly different between Big Sur temporal groups, signifying detoxification of PAHs, possible associated response to potential malignant transformation, and suppression of immune function as the primary responses of sea otters to fire in 2008 compared to those captured in 2009. In general, gene transcription patterns in the 2008 sea otters were indicative of molecular reactions to organic exposure, malignant transformation, and decreased ability to respond to pathogens that seemed to consistent with short-term hydrocarbon exposure.

California↗