The Human Cost
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The Human Cost: I worked with my friend, NPR journalist Christian Roselund, to depict the horrors and trauma after Hurricane Gustav ripped through the coast of southern Louisiana. The revelations and issues at the time have not changed since this last year’s aggressive storm season and it’s important to look back to see lessons learned and items still needing action.

Saltwater Intrusion On The Gulf Coast: An Assessment Of The Interactions Of Salinity Stress, Genetic Diversity And Population Characteristics Of Fish Inhabiting Coastal Marshes

A consequence of climate change

is the intrusion of saltwater into freshwater systems. Coastal Louisiana is currently experiencing higher than expected salinities in traditionally freshwater marshes and waterways. Studies of the effects of saltwater intrusion on resident animals are usually limited to documenting community changes. There has been little investigation of effects of saltwater intrusion on the demography and genetic structure. We propose to use the rapidly changing situation in Louisiana?s coastal marshes to understand how increasing salinity affects populations of resident fishes. Our objective is to examine how increasing salinity affects the ecology, demography, population structure, and genetic variation. The model organism for this research will be the western mosquitofish (Gambusia affinis) a wide spread and common predator that has been the subject of numerous studies on the effects of environmental stress on individual viability. We will test the hypothesis that increasing salinity is influencing genetic variation through demographic bottlenecks and local adaptation. We will also examine the hypothesis that fragmentation, associated with sea-level rise, will increase genetic differentiation among populations, as well as extinction of local populations.

We will assess demographic and genetic characteristics of populations

exposed to different levels of salinity stress in both the field and experimental mesocosms. . Field sampling will be conducted in two separate hydrological basins across a salinity gradient including fresh, intermediate, and brackish marsh. We will assay genetic variation using microsatellite and allozyme markers to determine if increased salinity leads to changes in genetic diversity and interpopulation genetic differentiation through effects on population size and habitat fragmentation. Using mesocosms, we will determine if losses of genetic diversity, likely to occur with decreases in population size resulting from salinity exposure, affect the viability of fish populations in recovering freshwater environments, as well as in habitats with continued exposure to increased salinity. Experimental manipulations and field sampling will also be used to determine if a population?s history of exposure to increased salinity affects subsequent viability in brackish and freshwater environments.

Publications and Presentations:

Publications have been submitted on this project: View all 15 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

coastal ecosystems, fish, fragmentation, genetic diversity, global climate, marshes, wetlands., RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, climate change, Oceanography, Aquatic Ecosystem, Environmental Monitoring, Atmospheric Sciences, Ecological Risk Assessment, Ecology and Ecosystems, wetlands, coastal ecosystem, fish habitat, climatic influence, global change, coastal environments, fisheries, fish communities, salt water intrusion, aquatic ecosystems, environmental stress, environmental stressors, habitat diversity, coastal ecosystems, estuarine ecosystem, ecosystem impacts, marsh ecosystem, global warming, aquatic ecology, ecosystem stress, sea level rise, genetic diversity, Global Climate Change

Progress and Final Reports:


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