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The first stage of information processing in the electrosensory system involves the encoding of local changes in transdermal potential into trains of action potentials in primary electrosensory afferent nerve fibers. To develop a quantitative model of this encoding process for P-type (probability-coding) afferent fibers in the weakly electric fish(More)
Oil stranded by the 1989 Exxon Valdez spill has persisted in subsurface sediments of exposed shores for 16 years. With annualized loss rates declining from approximately 68% yr(-1) prior to 1992 to approximately 4% yr(-1) after 2001, weathering processes are retarded in both sediments and residual emulsified oil ("oil mousse"), and retention of toxic(More)
In the aftermath of the 1989 Exxon Valdez oil spill, a Long Term Environmental Monitoring Program (LTEMP) has been regularly sampling mussels (and some sediments) for polycyclic aromatic and saturated hydrocarbons (PAH and SHC) at sites in Port Valdez, Prince William Sound, and the nearby Gulf of Alaska region. After 1999, a decreasing trend appears in(More)
Sampling zooplankton is a useful strategy for observing trace hydrocarbon concentrations in water because samples represent an integrated average over a considerable effective sampling volume and are more representative of the sampled environment than discretely collected water samples. We demonstrate this method in Port Valdez, Alaska, an approximately 100(More)
When crude oil or refined petroleum products are released into an aquatic environment, immediate changes in their chemical and physical properties occur as a result of several simultaneous weathering processes. These are evaporation, dissolution, dispersion into the water column, photochemical payne (4. The importance of photochemical processes in the(More)
Chemical analysis of large populations of floating (n=62) and stranded (n=1174) Macondo oils collected from the northern Gulf of Mexico sea surface and shorelines during or within seven weeks of the end of the Deepwater Horizon oil spill demonstrates the range, rates, and processes affecting surface oil weathering. Oil collected immediately upon reaching(More)
In-situ burning during the Deepwater Horizon oil spill generated tens of thousands of barrels of in-situ burn (ISB) residues in the northern Gulf of Mexico (GoM), most or all of which eventually sank to the seafloor. Chemical analyses showed that floating and sunken (~1400m deep) ISB residues (1) exhibited distinct n-alkanes and UCM profiles inconsistent(More)
Following the Deepwater Horizon oil spill, the spilled Macondo oil was severely weathered during its transport within the deep-sea plume as discrete particles, which were subsequently deposited on the seafloor. The Macondo oil deposited in deep-sea sediments was distinguished from ambient (background) hydrocarbons and naturally-seeped and(More)
Olefin-based synthetic-based drilling mud (SBM) was released into the Gulf of Mexico as a result of the Deepwater Horizon (DWH) disaster in 2010. We studied the composition of neat SBM and, using conventional GC-FID, the extent, concentration, and chemical character of SBM-derived olefins in >3600 seafloor sediments collected in 2010/2011 and 2014.(More)