Christopher B. Fuller

Comparative toxicity of oil, dispersant, and oil plus dispersant to several marine species

Dispersants are a preapproved chemical response agent for oil spills off portions of the U.S. coastline, including the Texas-Louisiana coast. However, questions persist regarding potential environmental risks of dispersant applications in nearshore regions (within three nautical miles of the shoreline) that support dense populations of marine organisms and are prone to spills resulting from human activities. To address these questions, a study was conducted to evaluate the relative toxicity of test media prepared with dispersant, weathered crude oil, and weathered crude oil plus dispersant. Two fish species, Cyprinodon variegatus and Menidia beryllina, and one shrimp species, Americamysis bahia (formerly Mysidopsis bahia), were used to evaluate the relative toxicity of the different media under declining and continuous exposure regimes. Microbial toxicity was evaluated using the luminescent bacteria Vibrio fisheri. The data suggested that oil media prepared with a chemical dispersant was equal to or less toxic than the oil-only test medium. Data also indicated that continuous exposures to the test media were generally more toxic than declining exposures. The toxicity of unweathered crude oil with and without dispersant was also evaluated using Menidia beryllina under declining exposure conditions. Unweathered oil-only media were dominated by soluble hydrocarbon fractions and found to be more toxic than weathered oil-only media in which colloidal oil fractions dominated. Total concentrations of petroleum hydrocarbons in oil-plus-dispersant media prepared with weathered and unweathered crude oil were both dominated by colloidal oil and showed no significant difference in toxicity. Analysis of the toxicity data suggests that the observed toxicity was a function of the soluble crude oil components and not the colloidal oil.

Behavior of a chemically-dispersed oil and a whole oil on a near-shore environment

Abstract To investigate the use of dispersants as an oil spill chemical countermeasure in the surf-zone, a simulated oil spill was conducted at the Shoreline Environmental Research Facility (SERF), formerly known as the Coastal OilSpill Simulation System (COSS), a wave tank facility in Corpus Christi, Texas. Sand was added to each tank to establish a beach with a prescribed slope of 10 degrees. Natural seawater flowed continually through the system to emulate alongshore currents. The replicated experimental treatments included pre-mixed oil plus dispersant (three tanks), oil only (three tanks), and unoiled controls (two tanks). Known amounts of either whole oil or dispersed oil were added to the respective tanks. Both the sediment and water column were periodically sampled during the 10-day experiment, and a materials balance on the oil was determined for both oil treatments. The environmental compartments where oil accumulated were sediments, water column, and non-aqueous-phase layer. The discharge from the tanks was presumed to be the primary sink, as water was drawn from the tanks at a known and constant flow rate. Tidal cycles were simulated by varying the computer-controlled influent rate. The oil mass (measured as total petroleum hydrocarbons) for each compartment/sink was calculated using data from four time points. At the experiment’s conclusion, approximately 49% of the applied oil for the oiled treatment remained in the tanks sorbed to sediments or other surfaces. The rest of the oil was removed via the effluent. In the chemically-dispersed oil treatment, all of the oil was flushed from the tanks; no oil (≪1%) remained on the sediments. These studies indicate that a timely dispersant application to spilled oil can reduce residual oil accumulation on beach substrates.

COMPARATIVE TOXICITY OF OIL, DISPERSANT, AND DISPERSED OIL TO TEXAS MARINE SPECIES

ABSTRACT Dispersants are one class of chemical response agents currently approved for use on offshore oil spills. However, questions persist regarding potential environmental risks of nearshore dispersant applications. To address these questions, the relative toxicity of weathered crude oil, dispersant, and weathered crude oil plus dispersant were compared. This study included one luminescent marine bacteria (Vibrio fisheri), two marine vertebrate (Cyprinodon variegatus and Menidia beryllina), and one invertebrate test species (Mysidopsis bahia). Both the vertebrate and invertebrate species were tested under spiked (short episodic) exposure regimes and 96-hour continuous exposure regimes using protocols developed by the Chemical Response to Oil Spills: Ecological Effects Research Forum (CROSERF) and U.S. Environmental Protection Agency (EPA), respectively. Toxicity to the marine bacteria was evaluated after a 15-minute exposure using the Microbics Microtox® system. Results showed no significant variance b...

NUCLEAR BASIC PROTEINS FROM THE BINUCLEATE DINOFLAGELLATE PERIDINIUM FOLIACEUM (PYRROPHYTA)1

Histories of the endosymbiont nucleus of the binucleate dinoflagellate Peridinium foliaceum Stein were prepared from isolated nuclei and analyzed by peptide mapping, ammo acid composition, and two‐dimensional gel electrophoresis. Using these criteria, we identified the presence of two HI‐like histories and the core histones H3, H2A, H2B, and H4. These histones are similar but not identical to those of the endosymbiont nucleus of the bi‐nucleate dinoflagellate Peridinium balticum Levander.

Development of a cheap, GPS-based, radio-tracked, surface drifter for closed shallow-water bays

This paper describes the development of an inexpensive (/spl sim/

Multi-parameter Instrument Array and Control System (MPIACS): a software interface implementation of real-time data acquisition and visualization for environmental monitoring

500), GPS-based, radio-tracked, surface-drifter system designed to operate within a closed shallow water bay. Texas bays and estuaries are generally shallow, weather/event driven, complex non-linear systems. In spite of the amount of activity that occurs within the bays, very little real-time information is collected. The Conrad Blucher Institute for Surveying and Science (CBI) at Texas A&M University-Corpus Christi is working toward better understanding of these bays by operating a pair of SeaSonde/spl trade/ HF Radar units within Corpus Christi Bay. This experience has shown the need for a specialized drifter that can be used in conjunction with the HF Radar operation and other bay research activities.

Sensing the coastal environment

Recent developments in sensor technology over the past decade have shifted the paradigm in environmental as well as oceanographic sampling and monitoring. The environmental and oceanographic scientific communities continue to deploy more and more in situ sensors either as single-unit deployments for generation of time-series and vertical profiles or as a towed-array for mapping environmental variables in surface waters in multidimensional space. Emergency response activities are also enhanced by way of real-time geo-referenced data acquisition using mobile in situ sensor arrays. Against this backdrop, we developed a software interface for real-time acquisition, analysis and visualization from a towed-array of sensors. This is the Multi-parameter Instrument Array and Control System (MPIACS) described in this paper and was used in the fall of 2002 during a mock oil-spill exercise in Corpus Christi Bay, Texas under he auspices of the Texas General Land Office (TGLO). The interface is designed for correlative visualization along the transect between as many as six state variables or environmental indicators allowing the implementation of adaptive sampling schemes. The software can also be used for scheduled sampling of water quality parameters in surface waters.

Estimating Colloidal Concentration Using Acoustic Backscatter

Abstract The spatial and temporal dynamics of near-shore ecosystems are being studied by the Conrad Blucher Institute for Surveying and Science at Texas A&M University-Corpus Christi with special consideration of episodic events associated with anthropogenic activity. Our growing array of estuarine and coastal monitoring stations in the Corpus Christi region supplies real-time, continuous input from a broad array of sensors (physical, chemical and biological) to feed comprehensive converged data sets that in turn foster, in a new context, the interpretation and evaluation of environmental perturba- tions (episodic events) and their ecological effects.

REALTIME GEO-REFERENCED DETECTION OF DISPERSED OIL PLUMES

Interest has grown for using acoustic Doppler current profilers (ADCPs) to measure suspended solids concentrations (SSC) in aqueous environments because of the ability to make simultaneous unobtrusive long-term multipoint measurements with high spatial and temporal resolutions. The acoustic backscatter intensity (ABS) measured by ADCPs is a function of the particle size distribution, concentration, and incident acoustic signal strength and thus provides the theoretical basis for measuring SSC. The applicability of using ABS from a 2400-kHz ADCP to estimate SSC in units of volume concentration over variable particle size distributions is evaluated in a controlled laboratory study. Results from this research show a log-linear relationship between ABS and volume concentrations over variable size distributions. Volume concentrations predicted from the sonar equation using measured ABS and empirically derived response coefficients compare well with the measured concentrations over the full range of concentrations and particle size distributions tested. The ABS response is shown to be linear with the theoretical Rayleigh scattering target strength, calculated from the empirical particle size distribution, and thus explains the observed linearity over a variable particle size distribution. These results indicate that ABS can be used to provide meaningful volume concentration estimates for characteristically variable colloidal suspensions.

Understanding particle-mediated contaminant transport through real-time monitoring

The current SMART protocol used by the U.S. Coast Guard relies on traditional ex-situ fluorometers that require physical transport of the sample from the water column to the instruments. While samp...