Thesis: The Chemical Oceanography lab welcomes the return of Ms Edem Mahu a PhD student from the University of Ghana working with Dr. Coale and Dr. Aiello to reconstruct the history of metal and organic pollution to 5 coastal estuaries on the Ghanian coast. In addition Edem will be refining her original methods for the determination of esterase activity (a proxy for living biomass) in hemipelagic and coastal sediments. The purpose is to develop a tool for determining impacts of oil drilling/spills to sediments.
Thesis:The effect of methylmercury body burdens on Chinook Salmon (Oncorhynchus tshawytscha) smoltification.
William Berkley Kauffman
Thesis: Analysis of Microbial Diversity in Elkhorn Slough Sediment along vertical geological gradients.
Thesis: Sediment Resuspension and Intermediate Nepheloid Layers in Soquel Canyon, Monterey Bay.
Thesis: Molecular, histological, and behavioral differences in largemouth bass (Micropterus salmades) and topsmelt (Altherinops affinis) exposed to methyl mercury.
Thesis: Photo-degradation of Methyl Mercury in the Sacramento-San Joaquin Delta Estuary.
Thesis: A 300-year geochronological assessment of atmospheric mercury deposition in California: implications for pre-anthropogenic biotic exposure.
Thesis: The impact of light availability on benthic oxygen release by the seagrasses Thalassia testudinum and Zostera marina.
Thesis: Mercury methylation in sediments from Coastal and Sierra watersheds: implications for methyl mercury mitigation in the San Francisco Bay-Delta Complex.
Thesis: A multi-proxy of the paleoclimate of the Monterey Bay National Marine Sanctuary during the Late Quaternary.
Thesis: The influence of dissolved copper on the production of domoic acid by Pseudo-nitzschia species in Monterey Bay California.
Thesis: Sediment accumulation and sedimentary diatom abundance on the continental shelf of Central California.
My thesis consisted of investigating the flux on metals out of the sediments in South San Francisco Estuary. Trace metals can be very toxic to many animal species and biaccumulate up the food chain into species that are consumed by humans. Many people utilize the Estuary as a source of sustinance yet they are contaminating themselves in the process. Understanding they cycling of these contaminants in the Estuary will enable us to better control the fate of all inhabitants in and around the area. Recycle for LIFE!.
Thesis: Dendraster excentricus distribution in Monterey Bay, California
Encarney’s thesis consisted of investigating the Chemical and biological mechanisms that control the precipitation and dissolution of arsenic, a redox-sensitive metalloid toxin, at the sediment-water interface in the South San Francisco Bay are described.
Rhodoliths, free-living calcareous red algae, create large and diverse habitats worldwide. Although these plants are abundant and ecologically important, little is known about their growth rate. We determined the growth rate for an individual rhodolith, Lithothamnium crassiusculum, from the southern Gulf of California through 14C analysis using Accelerator Mass Spectrometry (AMS). The growth rate was calibrated against the isotopic signature of a coral (Porites panamensis) with known growth rate. The comparison of “bomb” radiocarbon from this coral with an 18O based growth rate to the “bomb” radiocarbon record of the rhodolith indicated a rhodolith radial growth rate of 0.6 mm/yr. This growth rate suggests large L. crassiusculum, which have been found with radii in excess of 6 cm, may live over 100 years. Since rhodolith beds form important habitats for other species, this growth rate indicates recovery from disturbances will be slow. Declines in the ?14C record associated with the large El Nino events of 1957, 1982, and 1992 indicate 14C analysis may identify large past climatic events. The ability to determine past climate changes through AMS 14C analysis of rhodoliths would increase the geographic range of available climate records from the tropical oceans to the entire global ocean and potentially allow for the determination of paleoclimate from rhodoliths in fossil beds.
Worked on a hydrogen sulfide analysis using a technique without chemicals.
I worked with an in situ chemical analyzer (scanner) designed and developed by Dr. Ken Johnson. I used the scanner in conjunction with an Remotely Operated Vehicle (ROV) or a submarine to measure sulfur in “cold seeps” found on the ocean floor in Monterey Bay and off the coast of Costa Rica. Cold seeps are areas or cracks in the ocean floor where nutrients are actively expelled from the earth’s crust. Sulfur is an important alternative energy source for organisms (chemoautotrophs) living on the ocean floor, where sunlight is not available.
In the nearshore environment the sediments can be an important source or sink of trace metals. The whole purpose of our TEFLOM study is to better understand this environment. I am analyzing our TEFLOM data set, comparing different methods for doing trace metal flux calculations with an eye towards better understanding the movement of these metals into and out of sediments along the continental margin.
Thesis: The Shipboard Determination of Iron (III) in Seawater using Continuous Flow Analysis Colormetric Detection.
Thesis: Effects of sediment depth and season on growth and carbohydrate allocation in P. torreyi. by Barbara Plechner.
Thesis: Spectrophotometric Determination of Dissolved Manganese in Natural Waters: In Situ Chemical Mapping in Hydrothermal Plumes, with Concurrent Measurements of Total Dissolved Iron.