Dissertation/Thesis Abstract

The geochemical influence of trace element concentrations from marine sedimentary bedrock on freshwater streams in the western Transverse Mountain Ranges
by Caprile, Jose A., M.S., California State University, Long Beach, 2016, 125; 10134003
Abstract (Summary)

Government agencies assess the biological integrity of streams and the chemistry of groundwater to monitor anthropogenic impacts on freshwater ecosystems. Some of the impacted streams lack obvious stressors that can be linked to the impacts. In the case of elevated nutrients and ionic concentrations found in impacted stream sites within the Malibu Creek Watershed, research from the Las Virgenes Municipal Water District pointed towards the naturally occurring leachate from the Modelo formation, which contests previous studies suggesting an influence from anthropogenic activity. Differentiating between natural sources of trace element concentrations and point/non-point source contamination could aid in resolving water quality issues since monitoring occurs near anthropogenic development. Water, bedrock, and diatoms were sampled from spring, seep, and stream sites underlain by Tertiary sedimentary bedrock throughout the study area. Multivariate analyses revealed an association of groups driven by salinity along with a correlation between geochemistry and diatom assemblages. Mixing models and radar charts identified potential rock types as sources for analyte concentrations. Sites that were underlain by the Modelo formation presented brackish water conditions and high nutrient concentrations, which potentially influenced the diatom species compositions found at the spring/seep sites as a result of weathering.

Indexing (document details)
Advisor: Underwood, Dessie L. A.
Commitee: Allen, Bengt, Laton, William R.
School: California State University, Long Beach
Department: Biological Sciences
School Location: United States -- California
Source: MAI 55/05M(E), Masters Abstracts International
Subjects: Ecology, Biogeochemistry, Aquatic sciences, Geochemistry
Keywords: Bedrock leachate, Diatom species compositions, Sedimentary bedrock, Spring-fed streams, Water chemistry
Publication Number: 10134003
ISBN: 9781339925059
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