MARINE AND ATMOSPHERIC SCIENCES.
Vicechair: Jeffrey Lotz, University of Southern Mississippi
8:40 BOTTOM SCATTERING VARIABILITY DURING THE 1996 PANAMA CITY, FLORIDA, HIGH-FREQUENCY ACOUSTIC EXPERIMENT
Marcia A. Wilson [*], Jerald W. Caruthers , Ralph Goodman  and Steve Stanic , (1.) Naval Research Laboratory, Stennis Space Center, MS 39529 and (2.) Naval Research Laboratory on IPA from Pennsylvania State University, State College, PA 16804
An experiment was performed in shallow water near Panama City, Florida to study spatial variability of high-frequency bottom reverberation. A towed body with two transducer arrays installed at 15 and 40 degrees from horizontal was tested. The active transducer emitted a lms acoustic pulse every tenth of a second as the towed body moved over the relatively uniform sand bottom. Frequency rotated among 4 to 7 frequencies between 75 and 375 kHz. Reverberation envelopes for each frequency were plotted to show the changes in amplitude and arrival time for a series of pulses interacting with the bottom along the track of the towed body. An integrated reverberation level for each pulse was obtained. Several statistical analysis methods were used to determine whether changes in the reverberation probability density function were sufficient to indicate a difference in seafloor characteristics encountered. Analysis based on the chi-squared test was able to quantify differences between segments of data along a given tra ck.
9:00 A MODULAR OCEAN DATA ASSIMILATION SYSTEM
Daniel N. Fox [*] and Germana Peggion, Naval Research Laboratory, Stennis Space Center, MS 39529 and University of Southern Mississippi, Stennis Space Center, MS 39529
A scalable, rapidly relocatable ocean analysis and forecast system has been developed to provide accurate estimates of the acoustic environment. The system is built from reusable software modules, which facilitates adding or modifying capabilities, and runs well on a wide spectrum of computer hardware, from low-end workstations to supercomputers. In situ measured ocean profiles of temperature and salinity are optimally interpolated into a novel synthetic ocean environment which is generated using remotely sensed data and linear regressions derived from 100 years of measured profiles. This analysis is then used to initialize a robust, relocatable version of the Princeton Ocean Model, including tides. The system has been found to be much more accurate than other commonly used ocean climatologies and will be demonstrated in several areas including the northern Gulf of Mexico.
9:20 DYNAMICAL BALANCE IN THE INDONESIAN SEAS CIRCULATION
William H. Bumett [*] and Vladimir M Kamenkovich, Stennis Space Center, MS 39529-5001 and University of Southern Mississippi, Stennis Space Center, MS 39529
A high-resolution, regional, four-open port, nonlinear, barotropic ocean model (2D POM) is used to show that a pressure difference between the Pacific and Indian Ocean is not the dominant factor determining the total transport of the Indonesian throughflow. Two types of experiments were performed. In Experiment 1, the normal and tangential velocities at the ports are prescribed. The total transports through these ports are taken from analyses of historical observations, and the total inflow and outflow balanced to ensure mass conservation. Experiment 1's steady state results were used as boundary conditions for Experiment 2 where sea surface elevations and tangential velocities are specified at the open ports. To study the influence of the pressure head, the sea-surface elevation found in Experiment 1 was perturbed by a constant value at the open ports. A series of experiments were performed and the relative importance of the different terms in the momentum equations were analyzed both within and outside the equatorial zone.
9:40 HIGH PERFORMANCE VISUALIZATION OF METOC INFORMATION
George W. Heburn, Naval Meteorology and Oceanography, Stennis Space Center, MS 39529
Historically, graphical representations have been used to convey complex meteorological and oceanographic (METOC) information to the end user. Initially, this was in the form of hand drawn analyses of an iso-surface of some METOC parameter, i.e., pressure, temperature, etc. and sent to remote users via facsimile broadcast. Today, with the wide spread use of computers and the Internet, the primary conveyance of METOC is in the form of computer generated analyses of iso-surfaces and 2D and 3D grid fields of NIETOC parameters. As the desktop graphics workstations become more powerful and immersive display devices become more prevalent the opportunity exists to make better use of scientific visualization techniques to provide METOC information to the Warfighter. The Naval Meteorology and Oceanography Command (NMOC) in partnership with Mississippi State University (MSU), Jackson State University (JSU), and the Center for Higher Learning/University of Southern Mississippi (CHL/USM), has embarked on a High Performa nce Visualization Center Initiative (HPVCI). The HPVCI will create the infrastructure for ...a center without walls, in which the researchers can perform their research without regard to geographical location interaction with colleagues, accessing instrumentation, sharing data and computational resources, and accessing information in digital libraries. This will initially include efforts in the following: (1) collaborative scientific visualization; (2) the management/manipulation of very large geophysical and simulation data sets; (3) adaptive computation for battlefield tactics; and (4) electronic classroom, distance learning and educational outreach. The ultimate goal of this research program is to develop better visualization techniques to provide the Warfighter with the METOC information needed to exploit the natural environmental condition to his advantage.
10:20 A NEW GRADUATE DEGREE IN HYDROGRAPHIC SCIENCE AT THE UNIVERSITY OF SOUTHERN MISSISSIPPI
Denis A. Wiesenburg [*], Donald G. Redalje, and Andre Godin, University of Southern Mississippi, Stennis Space Center, MS 39529
A new graduate degree program in Hydrographic Science has recently been established by The University of Southern Mississippi (USM) Department of Marine Science. Along with the U.S. Navy, USM now offers, one-year non-thesis Master of Science degree in Hydrographic Science. Presently, there are no accredited academic programs in Hydrographic Science, within the United States, that are certified at the Category A level by the FIG/IHO International Advisory Board. The USM curriculum has been designed to meet requirements of the FIG/IHO Category A standards for academic proficiency in hydrographic surveying. The curriculum will be presented to the FIG/IHO International Advisory Board for certification in April 2000. The USM Department of Marine Science is located at the Stennis Space Center that is also the home of the U.S. Naval Oceanographic Office (NA VOCEANO), the Naval Research Laboratory-Stennis Space Center (NRL-SSC) and the NOAA National Data Buoy Center. Department of Marine Science faculty members, as well as other USM faculty with related knowledge and expertise, will actively participate in the delivery of this new graduate degree program in Hydrographic Science. Expertise from nearby industry and governmental agencies (e.g. NRL-SSC, NAVOCEANO) are also available to provide additional support to the program. The unique aggregation of hydrographers, oceanographers, and facilities at the Stennis Space Center provides an ideal location for this new program.
10:40 ONTOGENETIC CHANGES IN BIOCHEMICAL COMPOSITION OF RED SNAPPER LUTJANUS CAMPECHANUS
Kenneth R. Camp [*], Patricia M. Biesiot , and Jeffrey M. Lotz , (1.) University of Southern Mississippi, Hattiesburg, MS 39406-5018 and (2.) Gulf Coast Research Laboratory, Institute of Marine Sciences, Ocean Springs, MS 39566-7000
Changes in proximate analysis (protein and lipid), lipid classes, and fatty acid composition were monitored during early development of red snapper Lutjanus campechanus. Ova, embryos, and larvae from day 0 to 17 days post-hatch were sampled. Protein was the major constituent at 49-78% of the ash-free dry mass (AFDM) and increased consistently, in mass and proportion, between the embryo and 17 day old stages. Total lipids were highest in ova and embryos at 34% AFDM, decreased markedly to 12% AFDM by day 3 due to yolk absorption, and increased to 16% AFDM by 17 days post-hatch because of exogenous feeding. Proportions of major lipid classes changed during development. Sterol esters (SE) and triacylglycerols (TAG) occurred in ova but were almost completely depleted by end of the yolk sac stage (3 days post-hatch). By day 17, SE and TAG stores were replenished. Phosphatidyl choline and phosphatidyl ethanolamine remained at high levels throughout development, presumably conserved because of their roles as membran e lipids. The dominant fatty acids were docosahexaenoic acid (22:6[omega]3), palmitic acid (16:0), oleic acid (18:1[omega]9), eicosapentaenoic acid (20:5[omega]3), and linolenic acid (18:3[omega]3) which comprised, respectively, 35-40 mol%, 12-17 mol%, 8-12 mol%, 4-7%, 0-7% of the fatty acid pool. Partial funding was provided through NMFS/DOC grant number NA86FL0476.
11:00 PHYTOPLANKTON PIGMENTS AS INDICATORS OF ENVIRONMENTAL QUALITY IN ST. LOUIS BAY AND MISSISSIPPI SOUND
Karie E. Holtermann [*] and Donald G. Redalje, University of Southern Mississippi, Stennis Space Center, MS 39522
As part of an environmental quality study of the St. Louis Bay, Mississippi, samples were taken for High Performance Liquid Chromatography (HPLC) phytoplankton pigment analysis. Samples were taken at 9 stations during incoming and outgoing tides over the course of 9 months. Pigment analysis using HPLC followed the procedure of (Wright et al. 1991). A model using signature pigments as indicators of phytoplankton species was used to determine trends. In coastal and estuarine environments it is expected that larger phytoplankton such as diatoms or dinoflagellates will dominate due to their ability to utilize higher concentrations of nutrients found there. Smaller phytoplankton will dominate in oceanic environments where nutrients are not as abundant. Analysis of two stations, one representing an estuary environment inside St. Louis Bay and one representing the Mississippi Sound environment were compared. Diatoms were more abundant in the Mississippi Sound while dinoflagellates dominated in St. Louis Bay as show n by the presence of indicator pigments.
11:20 UTILIZATION OF A HYPERVARIABLE REGION AS A GENETIC TAG FOR RED SNAPPER, LUTJANUS CAMPECHANUS
Amber F. Garber [*], Kenneth C. Stuck, and Walter D. Grater, University of Southern Mississippi, Institute of Marine Sciences, Gulf Coast Research Laboratory, Ocean Springs, MS 39564
The ultimate goal of a marine finfish stock enhancement program is the release of hatchery-reared fish that successfully reproduce and interbreed with the receiving native populations. Since generational contributions of released fish cannot be estimated by physical tagging, a reliable genetic tag must be identified and employed. As part of an ongoing stock enhancement program for red snapper, Lutjanus campechanus, in the northern Gulf of Mexico, we assessed the potential for using a hypervariable region sequence of the mitochondrial DNA control region (mtCR) as a genetic tag. Total genomic DNA was extracted from 27 red snapper, amplified, cloned, sequenced, and aligned to determine the genetic structure of the mtCR. A hypervariable region of 170 base pairs (bp) was identified where 23 of the 27 red snapper were found to be unique. To assess the potential of this region for use as a genetic tag, total genomic DNA was extracted from additional red snapper and amplified utilizing primers that flank the hyperva riable region. These samples are currently being sequenced. Preliminary analysis of the sequence data indicates that the level of polymorphism in the hypervariable region may be useful in specific genetic population assessments at release sites.
11:40 FACTORS INFLUENCING POPULATION LEVELS OF THE STONE CRAB, MENIPPE ADINA IN MISSISSIPPI SOUND
Virginia Shervette [*], Harriet Perry , Patricia M. Biesiot , Kirsten Larsen , and James R. Warren , (1.) University of Southern Mississippi, Hattiesburg, MS 39406-5018 and (2.) Gulf Coast Research Laboratory, Institute of Marine Sciences, University of Southern Mississippi, Ocean Springs, Mississippi 39566-7000
Many marine organisms are restricted to habitats which provide essential refuge. The stone crab, Menippe adina, is associated with rock rubble jetties and oyster reefs in northern Gulf of Mexico estuaries. Lack of extensive hard bottom habitat, competition for limited space, and predation all operate to influence population levels. Establishment of low profile artificial reefs in Mississippi Sound provided an opportunity to investigate refuge limitation in juvenile stone crabs and to examine the roles of predation and inter-specific competition in controlling population levels. There is strong evidence that size-specific refuge limitation exerts control on both population size structure and density of stone crabs. Stone crab larvae and small juveniles (10-24 mm carapace width) are relatively abundant in Mississippi Sound and the species does not appear to be recruitment limited. Larger juveniles are less common and their numbers may be related to quantity and quality of suitable habitat. Competition for avai lable habitat may be acute between M. adina and other xanthid crabs (Eurypanopeus depressus and Panopeus simpsoni). Competition for habitat also occurs between stone crabs and the toadfish, Opsanus beta. Toadfish collected in the study area are active predators on the three xanthid taxa.
1:20 MITOCHONDRIAL GENETICS AND SYSTEMATICS IN THE GENUS PARALICHTHYS
Glenn M. Hendrix [*], Kenneth C. Stuck, and Walter D. Grater, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39564
Three species of Paralichthys occur in the Northern Gulf of Mexico: P. albigutta, P. lethostigma, and P. squamilentous. Paralichthys lethostigma is an important recreational and commercial species in Mississippi and is listed as a secondary species for possible enhancement by the U.S. Gulf of Mexico Stock Enhancement Consortium. There is little published information available on the genetics of Paralichthys, and no published mitochondrial DNA sequences for the three species in this study. We conducted this study to determine the potential of using 12S rRNA (commonly used for taxonomic identification of marine finfish) as a genetic marker for the identification of Paralichthys species from the northern Gulf. Total DNA was extracted from five individuals of each species and used as template for a PCR that amplified approximately 900 base pairs of the 12S gene. The resulting PCR fragments were gel purified, T/A cloned, and sequenced. The sequences were then screened for 30 restriction endonuclease sites, and it was found that a combination of Msp I and Xho I could be used to separate the three species. This molecular technique may be particularly useful for identifying otherwise indistinguishable specimens, such as newly hatched larvae.
1:40 OPTICAL AND PHYSICAL PROPERTIES CHARACTERIZE SURFACE DYNAMICS N THE CHESAPEAKE BAY PLUME
Michele Routhier [l][*], Robert A. Amone , and Richard Gould , (1.) University of Southern Mississippi, Stennis Space Center, MS 39529 and (2.) Naval Research Laboratory, Stennis Space Center, MS 39529
Surface optical and physical properties of the Chesapeake Bay plume are examined through a tidal cycle during the Chesapeake Bay Outflow Plume Experiment (COPE II, May 1997) to determine small scale structure of mixing processes. We describe the movement of the plume using surface salinity and the optical properties of absorption (a) and scattering (b) coefficients. Coupled with the shipboard measurements, five aircraft hyperspectral images over a 6-hour partial tidal cycle show the changing surface patterns. Surface a and b values from an ac9 instrument decreased along a 24 km offshore ship transect. The absorption coefficient at 412 nm decreased from 1.3 m-1 inside the plume to 0.1 m-1 outside, and the scattering coefficient at 555 nm decreased from 3.30 m-1 to 1.05 m-1. We compare the ac9 a and b measurements with estimates derived from the hyperspectral imagery. The short time and space scales resolvable with hyperspectral aircraft imagery makes it a unique tool for characterizing plume dynamics.
2:00 HEAVY METAL CONCENTRATIONS IN CHACEON QUINQUEDENS TISSUES FROM THE NORTHERN GULF OF MEXICO
Harriet Perry [l][*], Wayne Isphording , Christine Trigg , Newton Fawcett , Richard Waller , and Kirsten Larsen , (1.) University of Southern Mississippi, Institute of Marine Science, Gulf Coast Research Laboratory, Ocean Springs, MS 39566; (2.) University of South Alabama, Mobile, AL 36688; and (3.) University of Southern Mississippi, Hattiesburg, MS 39406-5043
The geryonid, Chaceon quinquedens, is common in slope waters of the eastern Gulf of Mexico (GOM) at depths greater than 400 fathoms. Highest concentrations of red crabs occur in the north central GOM in an area influenced by run-off from the Mississippi River. Their geographic location, close association with sediments, and protracted intermolt period favor accumulation of metal contaminants. Ten male and ten female red crabs were collected using molded plastic traps. Sediment and water samples were taken concurrently with trap collections. Crabs were dissected at sea and samples of gill, muscle, and hepatopancreas taken. Eggs were removed from ovigerous females. Trace elements/heavy metals were measured using inductively coupled plasma spectrophotometry and atomic absorption spectrophotometry. Concentrations for sediment and water were approximately [less than or equal to] levels previously reported for the GOM or other oceanic areas. Cu, Zn, As, Cd, Cr, Sn, Sc, and Hg levels in most wet tissues were found to be significantly higher than sediment levels. Bioaccumulation was most evident in the hepatopancreas, followed by the gills, and muscle tissue. Mean concentrations of Cr and Pb in wet muscle tissue were greater than FDA levels of concern.
2:20 THE HOLOCENE PALEOENVIRONMENT OF THE PEARL RIVER MARSH, MISSISSIPPI AND LOUISIANA
Richelle A. Hanson [*] and Charlotte A. Brunner, University of Southern Mississippi, Stennis Space Center, MS 39529
The goal of this study is to determine paleoenvironmental changes in the Pearl River Marsh using foraminiferal assemblages. The present-day marsh, located on the border of Mississippi and Louisiana, is microtidal with salinity ranging from fresh to brackish ([less than]12). Four 3" diameter vibra-cores were taken in a transect from the freshwater marsh, through the brackish marsh, and ending near Lake Bourne. The cores, which averaged 6 m in length, penetrated Holocene peats and sands, with three piercing the underlying Pleistocene Prairie Formation. A census of foraminifers was taken at 50-100 cm intervals in each core by microscope observation of wet samples. Consistent with the present-day salinity gradient, the assemblage from the upper 100 cm of the mid-marsh core is dominated by brackish, benthic, agglutinated foraminifers with a trace of saline species. In contrast, the assemblage includes only brackish species from 152-250 cm. There is an interval of barren peat from 305-369 cm. The assemblage below is similar to the surface assemblage. These results are interpreted as the response of the foraminiferal assemblage to changes in salinity caused by formation of the St. Bernard Lobe of the Mississippi River Delta. Prior to [sim]3500 yBP, the Pearl River Marsh experienced open exchange of fresh and salt water. During formation and activity between [sim]3500 and 1500 yBP, the St. Bernard Lobe isolated the Pearl River from the salt input from the Mississippi Sound. During subsidence of the St. Bernard Lobe, infiltration of sound waters progressively increased, leading to the present-day, brackish salinity.
2:40 Break; Divisional Business Meeting
3:00 ROLE OF SURFACTANTS IN PHYTOREMEDIATION
Julia S. Lytle [*], Thomas F. Lytle, and Larry Stewart, University of Southern Mississippi, Institute of Marine Sciences, Gulf Coast Research Laboratory, Ocean Springs, MS 39564
Contaminated sediments are a major concern in the marine environment. A promising alternate procedure for cleaning up contaminated sediments is through the use of plants, referred to as phytoremediation. Plants naturally ooze exudates from their roots that act as surfactants to release sediment-bound contaminants into the sediment pore water. Once contaminants are dissolved into the water, they are bioavailable to plants and other organisms. Uptake and degradation by organisms can effectively remediate the sediments. An experiment was designed to test the effect of two levels of a nonionic surfactant on the bioavailability of a polynuclear aromatic hydrocarbon (PAH), fluoranthene, for uptake by the estuarine plant, Sesbania vesicaria. The objective of the study was to determine what surfactant level is needed to effectively make sand-bound fluoranthene bioavailability to S. vesicaria. Seven microcosms, each containing three replicate treatments, were prepared with and without PAH contaminated sands and satur ated with either distilled water, water with a low surfactant concentration, or water with a high surfactant concentration. Controls were prepared for each treatment. After a six-week exposure, fluoranthene concentrations in plant tissue and sands were measured using a fluorescence spectrophotometer. Uptake was expected to be greatest in plants growing in contaminated sands wetted with the higher surfactant concentrations. Plant growth ( height, biomass and root elongation) was correlated with plant uptake of fluoranthene.
3:20 THE USE OF SEAWIES BIO-OPTICAL PROPERTIES TO TRACE FLORIDA'S HARMFUL ALGAL BLOOMS
Donna Thomas [*], Robert A. Arnone , Richard P. Stumpf , Karen Steidinger , and Brad Pederson , (1.) University of Southern Mississippi, Stennis Space Center, MS 39529; (2.) Naval Research Laboratory, Stennis Space Center, MS 39529; (3.) NOAA National Ocean Service, Silver Spring, MD 20910; (4.) Florida Department of Environmental Protection, St. Petersburg, FL 33701; and (5.) Mote Marine Laboratory, Sarasota, FL 34326
We traced the spatial and temporal extent of a Gymnodinium breve bloom off of the Florida panhandle from August through October 1999 using a time series of inherent optical properties (spectral absorption and back-scattering) and chlorophyll concentration derived from SeaWiFS imagery. High cell counts of Gymnodinium breve were correlated with SeaWiFS-derived chlorophyll concentration. We discuss the influence of elevated cell counts on the backscattering to absorption ratio and chlorophyll concentration derived from SeaWiFS. Improved atmospheric corrections and new iterative techniques allow SeaWiFS algorithms to be extended into the coastal environment to derive the bio-optical properties. SeaWiFS provides real-time trends of the bio-optical properties that help identify the environmental and biological cues used to predict the occurrence of future outbreaks of harmful algal blooms.
3:40 AMPHIPOD FAUNA OF LOW PROFILE ARTIFICIAL REEFS N MISSISSIPPI SOUND
Harriet Perry [*], Kirsten Larsen, Sara LeCroy, Christine Trigg, and James R. Warren, Institute of Marine Science, University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39566-7000
Artificial reefs serve as fish attractants and may increase production of some species by increasing habitat. Although over twenty low profile artificial reefs (oyster shell, concrete rubble, limestone gravel) have been constructed in Mississippi inshore waters, there are no data on reef community structure or the association of fish populations with these reefs. A study of the faunal assemblages associated with reef colonization in Mississippi Sound was begun in December 1998 as part of a larger program to assess productivity of these reefs in relation to recreational fishing opportunities. Colonization was studied by placing a series of crates filled with 0.025 [m.sup.3] of limestone gravel or oyster shell on a newly created limestone/shell reef. A portion of the crates are sampled at 3, 6, 9 or 12-month intervals and all organisms removed and counted. The present data are taken from the initial three-month colonization period. Amphipods were the most abundant macro-crustaceans associated with the reef mat erials. Two genera of free-living gammarideans dominated the amphipod fauna on both substrates: Melita and Apocorophium. There was no significant difference in the species composition between the two substrate types. Melita nitida was extremely abundant; Melita longisetosa and Apocorophium louisianum were also common in samples. Monocorophium acherusicum was found only in oyster shell samples in limited numbers.
4:00 Divisional Poster Session
DIET ANALYSES OF FISH ASSOCIATED WITH LOW PROFILE ARTIFICIAL REEFS IN MISSISSIPPI SOUND
Israel Anderson Denham [*], James R. Warren , and Jude LeDoux , (1.) Mississippi Gulf Coast Community College, Gautier, MS 39533 and (2) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566-7000
Artificial reefs have become important to the Mississippi Gulf Coast recreational fisheries. These inshore reefs promote tourism along the Gulf Coast by attracting sport fishermen. Over twenty inshore artificial reefs have been established in the Mississippi Sound. One reef (Gulf Park Estates) was chosen to provide information on the benthic organisms that colonize this reef and utilization of the reef by local fish species. During this study, samples were taken from the reef at three month intervals using entanglement gear. All fish were returned to the Gulf Coast Research Laboratory where stomachs were removed and preserved. Stomachs were removed from Menticirrhus americanus, Cynoscion arenarius, C. nebulosus, Leiostomus xanthurus, and Paralichthys lethostigma, and the stomach contents were analyzed. Ostracods, copepods, and cumaceans were found within stomachs from L. xanthurus. Stomach contents from M. americanus consisted primarily of unidentifiable fish remains. Cynoscion nebulosus and C. arenarius stom ach contents consisted predominately of fish and shrimp.
SAGA OF THE SEA TURTLES
Jennifer Hale, J.L. Scott Marine Education Center and Aquarium, University of Southern Mississippi, Biloxi, MS 39530
Sea Turtles have gained worldwide attention due to their endangered status. Human activity has contributed to their decline. Populations have been decimated by hunting, either for consumption or for the use of the shell in ornamentation, and by drowning as a result of being taken as by-catch. To add to their troubled future, many sea turtles are becoming infected with the fibropapilloma tumors which are growths that are virally caused. Discover how and why these fatal tumors are rapidly spreading through the sea turtle populations and what measures are being taken to help these animals survive. Materials will be provided to the attendees.
SEASONAL OCCURRENCE, ABUNDANCE, AND RECRUITMENT OF THREE XANTHID CRABS ON A LOW PROFILE ARTIFICIAL REEF
Christopher Hayesl [*], Kirsten Larsen , Harriet Perry , Christine Trigg , and James R. Warren , (1.) Cooperative Intern Program, Mississippi Gulf Coast Community College, Gautier, MS 39553 and (2.) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566-7000
The establishment of low profile artificial reefs composed of limestone gravel and/or oyster shell in coastal waters of Mississippi provided the opportunity to study the seasonal occurrence, abundance, and recruitment of three species of xanthid crabs (Eurypanopeus depressus, Panopeus simpsoni, and Menippe adina) associated with these structures. Menippe adina supports limited commercial fisheries in the northern Gulf of Mexico. The mud crabs, E. depress us and P. simpsoni, are ecologically important components of oyster reef communities. Plastic crates filled with either limestone or oyster shell substrate were placed on an existing low profile reef located in approximately 1.5 m of water. Four crates of each substrate were placed on the reef in each season (winter, spring, and summer). Crates were removed from the water after three months. Crabs were picked from samples and identified to species. Each crab was measured and weighed and a total number and weight by species recorded. Egg-bearing females were n oted. Recruitment occurred for all species in the late summer/early fall.
PRODUCTION OF PHYTOCHELATINS N PREDOMINANT MARSH PLANTS AS A RESPONSE TO SEDIMENT HEAVY METAL CONTAMINATION
Nicole A. Housley [*], Thomas F. Lytle , Kenneth McMurtrey , and Julia S. Lytle 2, (1.) Cooperative Intern Program, Mississippi Gulf Coast Community College, Gautier, MS 39533; (2.) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566-7000; and (3.) University of Southern Mississippi, Hattiesburg, MS39406
Of available methods to remediate metal contaminated soil, phytoremediation offers significant advantages. Use of plants to remove/immobilize metals in soils is effective in many applications and non-destructive to natural environmental systems. We have examined ability of coastal marsh plants to remove metals from contaminated sediments and the mechanisms of removal and storage in the plants. Many terrestrial and aquatic plants produce metal-binding phytochelatins, synthesized from glutathione in response to heavy metals. To determine whether marsh plants also produce these compounds and may serve to sequester and store these metals, we have tested Juncus roemerianus and Spartina alterniflora by spiking associated sediments with Cd and placing barriers around plants to restrict movement of the Cd. After a two month exposure, exposed and control plants were removed, tissue extracted, and phytochelatins derivatized before separation and quantification by HPLC. Associated sediments were analyzed for Cd and othe r metals (Cu, Zn, Ag, Cr, Ni, Pb, Co). These metals were fractionated into bioavailable and non-bioavailable by a simultaneous extraction procedure so that the presence and level of tissue phytochelatins could be related to quantity of heavy metals readily available to plants.
DEVELOPMENT OF A WEB SITE FOR HARMFUL ALGAL BLOOM SPECIES FOUND IN MISSISSIPPI SOUND
Elizabeth A. Quave [*], Cynthia A. Moncreiff , Todd A. Randall , and John D. Caldwell , (1.) Cooperative Intern Program, Mississippi Gulf Coast Community College, Gautier, MS 39553 and (2.) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs MS 39566-7000
Toxic and harmful algal bloom species that can occur in northern Gulf of Mexico waters will be featured on a web site under development by the authors. This site will include the classic "red tide" alga Gymnodinium breve, several species of Prorocentrum, Dinophysis caudata, and Alexandrium monilatum, plus several of the roughly 20 other potentially harmful algal species that are known to occur in coastal Mississippi waters. The site will be targeted toward the general public as a source of basic details on algal blooms, their causes, and the potential effects they can have on people, wildlife, and the environment. Species accounts will consist of photomicrographs, line drawings, and general life history information plus the possible effects of exposure to these harmful algal blooms. Videotapes of harmful algal blooms that occur during the project time frame will also be made using a microscope imaging system to aid in identification and will be included on the site.
THE EFFECTS OF HURRICANE GEORGES ON THE PELICAN ROOKERIES
Alison Sharpe, J.L. Scott Marine Education Center and Aquarium, Institute of Marine Sciences, University of Southern Mississippi, Biloxi, MS 39530
Along the coastal areas of the United States, the brown pelican can be seen soaring effortlessly over the marine and estuarine waters. Just a few years ago, the brown pelican was listed as an endangered species throughout its range. Today, in most areas, they have been removed from their endangered status. In September of 1998 Hurricane Georges struck the Mississippi coast, leaving a wake of destruction along tour mainland and decimating the brown pelican rookeries along the Chandeleur Island chain. This presentation will discuss the nesting problems and whether natural disasters, like hurricanes, might be a contributing factor that could return these marine birds to the endangered species list.
BIOCHEMICAL RESPONSES OF SESBANIA VESICARIA TO A POLYUNSATURATED AROMATIC HYDROCARBON, FLUORANTHENE
Larry Stewart [*], Julia S. Lytle, and Thomas F. Lytle, University of Southern Mississippi, Institute of Marine Sciences, Gulf Coast Research Laboratory, Ocean Springs, MS 39564
Bioremediation is one of the most promising developments in modern pollution control. Plants contain enzymes that can either detoxify the contaminant, or can stimulate bacteria in the rhizosphere which can degrade the contaminant. Plants release materials through their roots, referred to as exudates. This nutrient rich material is a food source to bacteria and also acts as a surfactant to solubilize soil-bound contaminants onto the plant roots. Some plant species are able to take up the contaminant into their tissue. However, plants cannot survive without defense mechanisms that allow them to cope with these contaminants. Many estuarine plants have evolved various mechanisms of defense. Glutathione, a known plant antioxidant can relieve oxidative stress and as an enzyme, can degrade toxins. Ascorbic acid is another antioxidant plants synthesize in response to oxidative stress. In a laboratory designed study, Sesbania vesicaria was grown in sands coated with 10 ppm fluoranthene. Two levels of surfactants were added to test containers to simulate the exudates' ability to reduce surface tension and solubilize contaminants. After 6 weeks of exposure, plant tissue (root and leaf) was extracted and glutathione and ascorbic acid levels were measured. The objective of the study was to determine what concentration level of surfactant is needed to solubilize sediment-bound fluoranthene and to assess the effect of elevated surfactant levels as a function of plant response.
8:40 TECHNIQUE DEVELOPMENT FOR SURFACTANT CHARACTERIZATION OF PLANT EXUDATES
Ashley D. Trahan [*], Larry Stewart , Julia S. Lytle , and Thomas F. Lytle , (1.) University of Southern Mississippi, Hattiesburg, MS 39406 and (2.) University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39564
Contaminated sediments pose a significant threat to environmental and human health. They are a major sink for a wide range of pollutants. An alternative method for cleaning up these waste sites is the use of organisms, primarily bacteria, and plants. Plants release exudates that act as a nutrient source for bacteria, and these materials also act as a surfactant which can help to solubilize sediment-bound contaminants. Bacteria have been identified that produce exudates specifically to facilitate the degradation of highly insoluble organic compounds and presumably plants may also behave similarly. Exudates can vary in composition depending on species and maturity of plant and the root rhizosphere. To better understand the role of exudates as surfactants, an experiment was designed to characterize exudates from Spartina alterniflora collected at different time intervals of their growth. Plants were grown under hydroponic conditions in order to easily collect plant water exudates. Ionic and nonionic standards w ere used to develop a technique for characterizing surfactants; using an Orion surfactant electrode. No evidence of cationic or anionic surfactants was found and nonionic surfactants analysis will require isolation from exudates before further analysis. Other experiments established the enhanced solubility of certain polynuclear aromatic hydrocarbons in aqueous solutions containing the S. alterniflora exudates and suggested the role these exudates may play in mobilization of sediment contaminants. Exudates were frozen for later analysis when further development of nonionic surfactant techniques are complete.
9:00 EFFECTS OF A RECURRENT COASTAL PLUME ON THE LIGHT ABSORPTION EFFICIENCY OF PHYTOPLANKTON SPECIES IN SOUTHEASTERN LAKE MICHIGAN
Kimberly A. Kelly [*], Steven E. Lohrenz , and Gary L. Fahnenstiel , (1)University of Southern Mississippi, Institute of Marine Sciences, Stennis Space Center, MS 39529 and (2)NOAA Great Lakes Environmental Research Laboratory, Muskegon, MI 49441
Microphotometric techniques were used to measure the light absorption characteristics of phytoplankton at the single-cell level. Typically, phytoplankton absorption has been determined at the community level using bulk measurements. Use of microphotometric techniques enables the direct measurement of the in vivo absorption efficiency factor [Q.sub.a](l) of individual cells. Light is an important variable controlling the development of the spring diatom community in Lake Michigan. This study examined the impact of a recurrent coastal plume on variations in light availability and the associated absorption characteristics of three phytoplankton groups in the vicinity of the plume. Three groups were examined including Aulacoseira islandica, Aulacoseira subarctica and smaller centric (8-10 mm) diatoms. The magnitude of [Q.sub.a](l) for all phytoplankton groups did not vary significantly with depth or time or across plume gradients. However, a comparison between species revealed that the spectral shape of [Q.sub.a ](l) differed in the blue wavelengths. The centric diatoms had a higher blue-to-red ratio than the Aulacoseira species. The possibility is considered that such differences in light absorption efficiency impart a competitive advantage that could contribute to the higher abundance of centric diatoms in plume assemblages.
9:20 HISTOPATHOLOGY OF WHITE SPOT VIRUS IN THE RED SWAMP CRAYFISH, PROCAMBAR US CLARKII
Rena Krol [*], K. Vijayan, Jeffrey M. Lotz, and Robin Overstreet, (1)Institute of Marine Sciences, Ocean Springs, MS 39566 and (2)Central Institute of Brackishwater Aquaculture, Madras, India
White spot virus (WSV), a major disease-causing agent in the shrimp aquaculture industry in the eastern hemisphere, can also infect Procambarus clarkii, the economically important freshwater crayfish from the southeastern U.S. This study examines WSV in Procambarus clarkii by transmission electron microscopy and light microscopy and compares the viral infection with that found in shrimp. Captive crayfish were injected with an inoculum of WSV-infected tissue from Penaeus monodon from India. In another experiment, crayfish were fed tissues of Litopenaeus vannamei which had been exposed to WSV-infected P. monodon. Gill, foregut, and cuticular epidermis were prepared for light microscopy. Foregut was prepared for transmission electron microscopy (TEM). By the second day post injection, animals exhibited lethargy and morbidity. No white spots appeared in the exoskeleton. By the fourth day, cumulative mortality was 100%. The feeding experiments ran for 17 days. Cumulative mortality at that time was 88% for crayfis h fed WSV-infected P. monodon and 50% for crayfish fed L. vannamei exposed to WSV-infected P. monodon. Histology revealed WSV infection in cell nuclei of the three tissues examined. TEM of foregut showed bacilliform virions 240-310 rim long by 80-100 nm wide. Some viions were found in membrane-bound vesicles in the cell cytoplasm. This study was funded in part by USDA, CSREES Award No. 98-38808-6019.
9:40 DISSOLVED RARE EARTH ELEMENTS IN THE LOWER MISSISSIPPI RIVER
Alan M. Shiller [*], Julie Havens, and Robyn Hannigan , (1.)University of Southern Mississippi, Stennis Space Center, MS 39529 and (2.)Old Dominion University, Norfolk, VA 23529
Rare earth elements (REEs) form an unique series in which incremental changes in chemical properties occur across the series as a result of decreasing ionic radius as f-shell electrons are filled in. In general it is found that heavier REEs are preferentially complexed in solution whereas lighter REEs are preferentially sorbed to particle surfaces. Most of the REEs are found in the trivalent oxidation state in natural waters. However, oxidation of Ce(III) to Ce(IV) and subsequent scavenging removal of Ce(IV) can lead to lower than expected dissolved concentrations of this element (the so-called Ce anomaly). In our study, dissolved REE concentrations were determined in a monthly time series of the lower Mississippi River which was conducted from October 1991 to December 1993. Overall our results agree with limited previous investigations; i.e., the river shows enrichment of heavy REEs relative to light REEs and also has a significant Ce anomaly. However, the previous investigations relied on only single sampl es from the river. Our seasonal investigation reveals significant temporal variations in the river's REE chemistry. In particular, we observe substantial (and generally correlated) variations in heavy REE enrichment and Ce anomaly. Overall the most fractionated (with respect to crustal composition) waters generally occur in winter and spring and the least fractionated waters occur in summer.
10:00 RESISTANCE OF NAIVE AND PREVIOUSLY EXPOSED LITOPENAEUS VANNAMEI (CRUSTACEA: PENAEIDAE) TO TAURA SYNDROME VIRUS OR WHITE SPOT VIRUS
Anne Marie Moore [*], Jeffrey M. Lotz, and Verlee Breland, Gulf Coast Research Laboratory, Institute of Marine Sciences, University of Southern Mississippi, Ocean Springs, MS 39566-7000
Taura syndrome virus (TSV) and white spot virus (WSV) are the two most important shrimp pathogens affecting aquaculture of the white-legged shrimp Litopenaeus vannamei in the Western Hemisphere. A matter of days after exposure to TSV the mortality in a population of cultured L. vannamei is typically 75% whereas mortality after exposure to WSV is likely to be 90%. As part of an ongoing study on the pathology and epidemiology of TSV and WSV we undertook to compare the survival of naive L. vannamei and survival of previously exposed L. vannamei to re-challenge with the homologous virus. Shrimp between 1 and 5 g were exposed by feeding infected shrimp cephalothoraces at a rate of 3% body weight. Survivors of such primary exposures were used for subsequent re-exposures to virus. Several re-exposure experiments were performed with the TSV and WSV survivors. In a typical experiment 12 TSV survivors were challenged with TSV and 10 WSV survivors were challenged with WSV. After 21 days the TSV survivors challenged wit h TSV had 0% mortality whereas the WSV survivors rechallenged with WSV had 100% mortality after 5 days. It appears that surviving a TSV challenge imparts resistance to rechallenge with TSV whereas survival of a WSV challenge does not impart resistance to re-challenge with WSV. Partial funding was provided through USDA/CSREES grant number 98-388086019.
10:40 CALIBRATION OF SPLIT-FLOW THIN-CELL (SPLITT) FRACTIONATION
Toshi Uozumi [*] and Alan M. Shiller, University of Southern Mississippi, Stennis Space Center, MS 39529
Split-flow thin-cell (SPLITT) fractionation is a continuous particle separation technique which is relatively new and still under development. SPLITT is a rapid hydrodynamic separation technique applicable to environmental samples. Separation is achieved using the gravitational settling of particles as they traverse the SPLITT cell. Each operation separates particles into two fractions at a certain cutoff diameter which can be easily changed by adjusting flow rates (i.e., the transit time of particles through the SPLITT cell). In theory, the necessary flow rates are predictable by first principle calculations; however, the actual cutoff diameter does not always match the theoretical cutoff diameter. This seems to be the case especially when a sample contains particles with differing densities. Therefore, the cutoff diameter requires calibration by measuring the actual size of the separated particles. This procedure can be done by using a combination of SEM and an image-processing program with a capability of quantifying particle dimensions. In our study, river particles ( 1-64 microns) taken from the Mississippi River are separated into four different size fractions using the SPLITT technique. The separation of Mississippi River suspended particles is a first step in work aimed at understanding the nature of seasonal changes in the surface area of the river particles.
11:00 SIZE-DEPENDENT VARIATIONS OF PHYTOPLANKTON SPECTRAL ABSORPTION IN COASTAL WATERS SOUTH OF CHESAPEAKE BAY
Steven E. Lohrenz [*], Christopher L. Carroll , and Alan D. Weidemann , (1.) University of Southern Mississippi, Stennis Space Center, MS 39529 and (2.) Naval Research Laboratory, Stennis Space Center, MS 39529
Critical to our understanding of coastal ecosystems is knowledge of phytoplankton distributions. Our ability to characterize phytoplankton distributions in coastal environments has the potential to be greatly enhanced by the application of remote sensing. One factor contributing to uncertainty in estimates of pigment concentrations by remote sensing is variability in pigment absorption coefficients. The coastal region south of Chesapeake Bay is an excellent area to examine consequences of variability in phytoplankton communities. Various studies have noted differences in phytoplankton size and taxonomic composition among different water masses in the region. Our objective was to examine whether variations in pigment spectral absorption accompanied the differences in phytoplankton size and taxonomic composition. The shapes of the pigment absorption spectra for near-shore low salinity (plume) stations were characterized by lower blue-to-red absorption ratios than was the case for higher salinity stations furth er offshore. The spectral shapes of the [less than]3 micron size fractions at the near-shore stations were similar to those observed at the offshore stations indicating that the observed differences in spectral shape were size-related. Our findings demonstrate that characterization of pigment absorption by remote sensing must take into account variations in phytoplankton size and associated absorption properties.
11:20 THE EFFICACY OF THREE MARSH PLANTS IN PHOTOREMEDIATION OF HEAVY METALS
Jeffrey Lyons [*], Nathaniel Smith , Thomas F. Lytle , and Julia S. Lytle , (1.) Vanderbilt University, Nashville, TN; (2.) Alcom State University, Alcorn State, MS 39096; and (3.) University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39564
Phytoremediation, vegetation-enhanced bioremediation, offers an attractive alternative to conventional means of decontaminating sediments. Little research has explored use of coastal marsh plants in phytoremediation of sediments. Three prominent marsh plants, Juncus roemerianus, Spartina alterniflora, and Sagittaria lancifolia and associated sediments were collected from a Department of Defense site with known elevated levels of heavy metals, from Ocean Springs Harbor and also from a control site in Ocean Springs. Plant roots and leaves were acid digested and analyzed by either flame or furnace atomic absorption spectrophotometry for Cu, Zn, Co, Ag, Cr, Cd, Ni and Pb. Sediments were digested to remove "bioavailable" fractions of metals associated with either iron oxide, manganese oxide or organic phases. S. lancifolia (being most exceptional in ability to translocate metals from roots to leaves) and S. alterniflora generally contained higher uptake levels of metals than J. roemerianus with Cd, Cu and Ni bein g most dramatically accumulated. Pb and Zn were less well accumulated. Cr though at high total levels occurred in sediment mostly in forms not readily available to plants and was at very low levels in plant tissues and vividly demonstrates the importance of defining sediment metals in terms of "bioavailable" rather than total amounts as a level most environmentally meaningful.
11:40 TRANSMISSION OF WHITE SPOT VIRUS TO LITOPENEAUS VA NNA MEI (CRUSTACEA: PENAEIDAE)
M. Andres Soto [*], and Jeffrey M. Lotz, Gulf Coast Research Laboratory, Ocean Springs, MS 39566-7000
White spot virus can cause up to 100 % crop mortality on shrimp farms. The transmission coefficient, [beta], derived from a mathematical epidemiology model with the Reed-Frost method of pathogen transmission was used to compare transmission from cannibalism to transmission from water of white spot virus to Litopeneaus vannamei, The formula for estimating the transmission rate is: [beta] = 1 - exp (([S.sub.1] I [S.sub.o] / [I.sub.o] where, [S.sub.o] and [I.sub.o] are the number of susceptible and infected animals, respectively, at the beginning of the experiment, and [S.sub.1] are the number of susceptible animals at the end of the experiment. Twelve susceptible animals ([S.sub.o]) were placed in each of nine cylindrical tanks (surface area = 1 [m.sub.2). In four tanks, shrimp were allowed to cannibalize one dead, infected shrimp, and shrimp in four other tanks were exposed by cohabitation to one infected shrimp. Shrimp in one tank served as the negative control. After 14 hours all shrimp were isolated to avo id further exposure from newly infected shrimp and at day four the experiment was stopped. All shrimp were examined histologically for white spot virus. The transmission coefficient from cannibalism was 0.38, and from water was zero. Partial funding was provided by USDAICSREES grant # 98-38808-6019.