Marine and atmospheric sciences.
Vicechair: Patricia Biesiot, University of Southern Mississippi
Deer Isle Room
8:30 EFFECTS OF TEMPERATURE, SALINITY, AND FEEDING RATE ON BUDDING OF DRY-MONEMA DALMATINUM SCYPHISTOMAE
Brian [Ortman.sup.*] (1) W. Monty Graham (2), and Patricia M. Biesiot (1), (1.) University of Southern Mississippi, Hattiesburg, MS 39406, and (2.) Dauphin Island Sea Lab, Dauphin Island, AL 36528
Drymonema dalmatinum, a large non-indigenous scyphozoan jellyfish, appeared in the northern Gulf of Mexico during fall 2000. Planulae, shaken from the brooding structures of adult medusae caught in the field, settled and metamorphosed into scyphistomae in the lab and were maintained in culture. Individual polyps were placed into separate wells in six-well tissue culture plates to monitor asexual budding for two weeks. Combinations of four temperatures (15, 20, 24, 30[degrees]C), three salinities (15, 25, 35 ppt), and two feeding regimes (newly-hatched Artemia nauplii either once or three times per week) were used, for a total of 24 treatments with two replicates per treatment. The number of scyphistomae in each well was counted three times per week to determine colony size. Budding did not occur in any of the 15[degrees]C or 15 ppt treatments. Although budding occurred among scyphistomae fed once a week at the higher salinity and temperature combinations, colony sizes were small (2 or 3 polyps) and the result s were not significantly different among treatments. Colony size was significantly greater (4 or 5 polyps) among scyphistomae fed three times per week in all treatments at the higher salinities and temperatures. Scyphistomae of D. dalmatinum appear to require temperatures greater than 15[degrees]C, salinities greater than 15 ppt, and frequent feeding for successful colony growth.
8:45 GEOGRAPHIC ASSESSMENT OF BLUE CRAB CALLINECTES SAPIDUS: EMBRYO SIZE, FECUNDITY, AND BIOCHEMICAL COMPOSITION
Kristin N. [Ealy.sup.*] and Patricia M. Biesiot, University of Southern Mississippi, Hattiesburg, MS 39406
The present study was conducted to determine if embryo size, fecundity, and the biochemical composition (protein, carbohydrate, lipid, ash) of embryos and ovaries varied among populations of blue crab Callinectes sapidus Rathbun over its range in U.S. waters. Ovigerous crabs were obtained during summer 2000 from coastal sites in three biogeographic provinces: Virginian, Carolinian, and Louisianian. Mean embryo diameter per female ranged from 243-309 [micro]m and mean individual embryo dry weight ranged from 2.3-2.9 [micro]g; neither measure was significantly different among the provinces. Fecundity was estimated using a direct count/dry weight method and ranged from 1.6-6.2 million embryos per crab; larger females exhibited greater fecundity. Mean fecundity was greatest for Carolinian crabs (3.5 million embryos per female) followed by Louisianian (3.1 million) and Virginian crabs (2.2 million) and was significantly different only between Virginian and Carolinian crabs (P = 0.030). There were no significant re lationships between embryo diameter and female body size or between embryo diameter and fecundity. Although no significant differences were observed in embryo biochemical composition among the provinces, there were significant differences in ovarian composition between Virginian and Carolinian crabs for carbohydrate (P 0.026) and for ash (P = 0.006). Minor differences in embryo size, fecundity, and biochemical composition occur among blue crabs from the three provinces but the variations are not predictable and likely do not indicate geographic influence.
9:00 VIABLE BUT NONCULTURABLE ESCHERICHIA COLI: A STUDY COMPARING THE DIRECT VIABLE COUNT PROCEDURE WITH MEMBRANE FILTRATION FOR TOTAL E. COLI AGAR ENUMERATION
Andrea M.B. [Phillips.sup.*] (1) D. Jay Grimes (1), and Judith L. Williams (2), (1.) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566, and (2.) University of Southern Mississippi Gulf Coast, Long Beach, MS 39560
Escherichia coli, a common fecal coliform bacterium, is used as a biological indicator species for the detection of fecal pollution in marine waters. Viable but nonculturable E. coil are living cells, which are dormant and cannot be cultured using current EPA standard microbiological enumeration methods. This inability to culture the cells is thought to result from low nutrient sources, temperature and salinity fluctuations, and/or other environmental factors. However, the Direct Viable Count (DVC) procedure allows for the microscopic enumeration of all living or viable bacteria in the marine environment by incubation with an anti-microbial agent and a nutrient food source that collectively bring the bacteria out of dormancy. Nalidixic acid (NA) is used as the anti-microbial agent; it is a gyrase inhibitor that prevents DNA synthesis by disallowing septum formation and thus, prohibiting cell division. Yeast extract (YE) as the food source allows the cells to continue metabolizing nutrients, meanwhile growing elongated or fattened during incubation. To quantify the exact number of viable but nonculturable cells in a given sample, the DVC number has to be compared to the mTEC method (EPA 1103.1) for total E. coli, by the membrane filtration procedure. Results thus far have yielded a significantly higher amount of E. coli detected using the DVC method over the mTEC method suggesting that the present E. coli detection methods may be under estimating true numbers and needs to be reevaluated.
9:15 ACOUSTIC SEAFLOOR CHARACTERIZATION IN ONSLOW BAY FROM EM 121A HYDROPHONE DATA
Frank W. [Bentrem.sup.*] and John Sample, Naval Research Laboratory, Stennis Space Center, MS 39529
Acoustic inversion of Simrad EM 121A multibeam sonar data is presented for seafloor sediment classification in Onslow Bay. The sonar hydrophone data is beamformed and calibrated and transformed into backscattering strength vs. grazing angle. The Mourad-Jackson backscatter model is used to invert the data via simulated annealing to obtain mean sediment grain size. The inversion results agree with the ground truth sediment type (sand) along the entire shiptrack and closely agrees with the ground truth in grade of sand (i.e., very fine, fine, medium, coarse, very coarse) in areas with significant sediment layers (deeper than one meter).
9:30 ANALYSIS OF TEMPERATURE AND SALINITY VARIABILITY IN THE MISSISSIPPI SOUND BASED ON NGLI CTD DATA
Sergey [Vinogradov.sup.*], Nadya Vinogradova, Vladimir Kamenkovich, and Dmitri Nechaev, University of Southern Mississippi, Stennis Space Center, MS 39529
The analysis of interannual, seasonal and daily variations of temperature and salinity for the region of Mississippi Sound has been performed using the Northern Gulf of Mexico Littoral Initiative (NGLI) in-situ data. The results of physical and numerical analysis of six CTD (conductivity-temperature-salinity) surveys, R/V Pelican cruises in February, May, November 1999 and January/February, May, August/September 2000, will be represented in this report. The data of 25-hour stations have been used to analyze temperature and salinity daily variations and identify underlying physical mechanisms. Estimation of seasonal and interannual variances of temperature and salinity fields is important for ocean modeling systems. It has been applied in calibration and validation of the operational numeric model, ECOM (Estuarine, Coastal and Ocean Model) in the region of the Northern Gulf of Mexico.
9:45 BAROTROPIC AND BAROCLINIC CIRCULATION PATITERNS WITHIN THE INDONESIAN SEAS
William H. [Burnett.sup.*] and Vladimir Kamenkovich, University of Southern Mississippi, Hattiesburg, MS 39406
An extensive series of numerical experiments using anon-linear, high-resolution ocean model centered over the Indonesian Seas are performed to investigate the fundamental dynamics of the Indonesian Seas Throughflow. The model is initialized with seasonally varying prescribed transports through four open ports that simulate the Pacific and Indian Ocean major currents. Atmospheric coupling is accomplished with local monthly wind stresses from the Hellerman and Rosenstein climatology. Results from the barotropic experiment with no wind forcing reveal that the Mindanao Current splits towards the Makassar Strait, the Malucca Sea, and the Halmahera Sea and exits via the Lombok, Sumba, Ombai Straits, and the Timor Sea. Barotropic experiments with local wind forcing reveal that the majority of the Mindanao Current transport flows toward the North Pacific Ocean during the southeast boreal monsoon, and towards the Celebes Sea during the northwest boreal monsoon. Results from the baroclinic, high-resolution model with a nd without wind forcing will also be discussed.
10:15 DIURNAL FEEDING HABITS OF FLORIDA POMPANO (TRACHINOTUS CAROLINUS)
Kersten [Wheeler.sup.*], Richard W. Heard, and Chet F. Rakocinski, USM-Gulf Coast Research Laboratory, Ocean Springs, MS
Florida pompano are well known for being sought after by commercial and recreational fishermen for their delectable flesh. Relatively little information is available on the feeding habits of Florida pompano (Trachinotus carolinus) from the northern Gulf of Mexico. Previous studies on pompano have speculated that these fish are diurnal feeders without any confirmation. We conducted a diel feeding study over a 24 hour period during the summer of 2001 on a protected barrier island beach in Alabama. This study was conducted in order to determine any shifts in diet preferences over the course of a day and to determine pompano diel feeding chronology. Fish were collected every 4 hours for gut content analysis. We found that pompano were feeding in the early morning hours and in the afternoon. We were unable to determine if pompano were actively feeding at night but future research may be able to conlude whether pompano are truly diurnal feeders.
10:30 HABITAT UTILIZATION BY JUVENILE FISHES IN THE WESTERN MISSISSIPPI SOUND
Ramsey [Wash.sup.*], Kirsten M. Larsen, Harriet Perry, and Christine Trigg, Cooperative Internship Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553, and J.L. Scott Marine Education Center and Aquarium, The University of Southern Mississippi, Biloxi, MS 39530
Estuarine habitats contribute substantially to the productivity of selected fishery species. The link between the amount of vegetated habitat and fishery production is well established in the Gulf of Mexico. Most of the information on fish species inhabiting near-shore areas in Mississippi coastal waters is from the central and eastern Mississippi Sound; there is little data available for the western Sound. Knowledge of habitat utilization by juvenile fishes is especially critical for the western Mississippi Sound because this area is heavily influenced by freshwater intrusion from Lakes Pontchartrain and Borgne. In years with heavy rainfall and/or snowmelt, spillways along the Mississippi River open and floodwaters are diverted into the Mississippi Sound. In this study, marsh edge and open water habitats were sampled using a drop sampler. The sampler consisted of a bottomless fiberglass cylinder one meter in diameter which enclosed 0.78 [m.sup.2] of bottom. The samples were taken weekly from March through Ju ly. Juvenile fishes were removed from samples, measured to the nearest millimeter and weighed to the nearest 0.1 gram. Determination of the distribution and abundance of juvenile fishes will identify critical habitat and provide information necessary for assessment of changes that may occur as a result of freshwater diversion activities.
10:45 CHEMICAL ANALYSIS OF FISH TANKS
Ryan [Pew.sup.*], Cherie [Pringle.sup.*], and Rick Kastner, Cooperative Internship Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553, and J.L. Scott Marine Education Center and Aquarium, The University of Southern Mississippi, Biloxi, MS 39530
Our project was to test the water quality in the tanks in the J.L. Scott Marine Education Center and Aquarium. The parameters included: pH, salinity, oxygen content, and temperature to determine the optimal range for marine life. An oxygen meter was used to find the levels of oxygen that is present in the water. A pH meter was used to determine the pH and the temperature. A pH meter tests the level of hydrogen ions that are present within the water. Each week tests were administered on the tanks to determine changes in pH, oxygen content, salinity, and temperature. This data was then recorded each week on a chart for analyses. We will present the result of our study.
11:00 A SURVEY OF THE CHEMICAL HYDROLOGY OF THE ST. LOUIS BAY ESTUARY
Amanda [McPeek.sup.*], Jeremy Bell, Christine Trigg, Faye Mallette, and Harriet Perry, Cooperative Internship Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553, and J.L. Scott Marine Education Center and Aquarium, The University of Southern Mississippi, Biloxi, MS 39530
The St. Louis Bay watershed is one of four major estuaries of the Mississippi Sound and has traditionally been considered relatively pristine in water quality. Recent population growth and expanding industrial development have placed increased pressure on the natural resources of our coastal estuaries. Hydrological sampling of St. Louis Bay was conducted as a part of a larger study examining the environmental health of the Mississippi Sound (Gulf of Mexico Estuarine Inventory and Study, Mississippi, 2001). Surface and bottom water samples were collected using a 2.5 L Niskin bottle. Seven stations were sampled starting upstream in the Jourdan River, extending through the St. Louis Bay, and into the Mississippi Sound. Water temperature, salinity, and dissolved oxygen were measured in the field using a YSI dissolved oxygen meter. Ammonia, nitrite, nitrate, orthophosphate, and total phosphate concentrations were measured in the laboratory using standard methods of chemical analyses. Sampling was conducted in the fall and winter of 2001. Hydrological data were compared seasonally and with historical data from the study area.
11:15 A SURVEY OF THE HYDROLOGY OF BAYOU CASOTTE
Jeremy [Bell.sup.*], Amanda McPeek, Christine Trigg, Faye Mallette, and Harriet Perry, Cooperative Internship Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553, and J.L. Scott Marine Education Center and Aquarium, The University of Southern Mississippi, Biloxi, MS 39530
Bayou Casotte is a heavy industrialized bayou of the Mississippi Sound and has traditionally been considered less pristine than other coastal areas. Recent population growth and expanding industrial development have placed increased pressure on the natural resources of our coastal estuaries. Hydrological sampling of Bayou Casotte was conducted in conjunction with a larger study examining the environmental health of the Mississippi Sound (Gulf of Mexico Estuarine Inventory and Study, Mississippi, 2001). Surface and bottom water samples were collected using a 2.5 L Niskin bottle. Seven stations were sampled starting from the upper reaches of Bayou Casotte to its mouth in the Mississippi Sound. Water temperature, salinity, and dissolved oxygen were measured in the field using a YSI dissolved oxygen meter. Ammonia, nitrite, nitrate, orthophosphate, and total phosphate concentrations were measured in the laboratory using standard methods of chemical analysis. Sampling was conducted in the fall and winter of 2001. Hydrological data were compared seasonally and with data from another study conducted simultaneously in St. Louis Bay.
11:30 Divisional Business Meeting
Deer Isle Room
1:00 IMPACT OF AGRICULTURAL PESTICIDES WITHIN WEEKS BAY, A NATIONAL ESTUARINE RESEARCH RESERVE
Julia S. [Lytle.sup.*] and Thomas F. Lytle, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566
Spiraling releases of pesticides in coastal watersheds have impacted our Gulf estuaries. Baldwin County, Alabama is historically dominated by agricultural activities; Fish and Magnolia Rivers drain the watershed that empties into Weeks Bay National Estuarine Research Reserve, located in Baldwin County. A study was designed to trace the transport of pesticides through the watershed, measure loads, and assess fate and impact of these pesticides on Weeks Bay. Sixty-seven sites within the rivers, Weeks Bay and Mobile Bay were chosen for sampling water, sediment and macrophytes. Samples were collected both routinely as well as after heavy rain events. Pesticides measured in highest concentrations within Weeks Bay were simazine, atrazine and 2,4-D. Results of this three-year study showed that transport of pesticides was pronounced near the source and that each river had pesticide profiles that were unique to the agricultural practices in those drainage regions. Once riverine input reached Weeks Bay, the high flushi ng rates within the shallow estuary homogenized bay sediments, losing the distinctive fingerprints of each of the river inputs. Toxicty tests using sediment and pore water indicated a minimal impact within the Bay while some sites within the rivers showed slightly higher toxicity. High suspended sediment loads possibly transports pesticides into Mobile Bay where they are dispersed.
1:15 MARSH PLANTS: VALUABLE ALLIES IN COMBATING ESTUARINE POLLUTION BY. PETROLEUM HYDROCARBONS
Thomas F. [Lytle.sup.*] and Julia S. Lytle, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566
The marsh plant, Juncus roemerianus, possesses properties that may uniquely qualify it to aid in efforts to decontaminate sites with problematic levels of sedimentary hydrocarbons, e.g. military installations. In collaboration with environmental officers of Keesler Air Force Base sites of hydrocarbon contamination populated by this plant were examined to determine potential of use of this plant for sediment clean up. It was found that in contrast to J. roemerianus found at uncontaminated sites or to other marsh plants, J. roemerianus growing in contaminated sediments produced large quantities of soap-like substances in the rhizophere. This suggested that our previous observations of ability of this plant to uptake virtually insoluble hydrocarbons may have stemmed from a contaminant response in the plant to release surfactants into surrounding soil to aid in dissolution of hydrocarbons. In examining the leaves from these plants it was found that both aliphatic and aromatic hydrocarbons occurred in levels very similar to that found in the sediments and much higher than in plants growing in clean areas. Most intriguing was the modification that occurred to aromatics in leaves during translocation process indicating extensive reworking or degradation of the aromatics. Additional work is underway to determine how this plant is able to solubilize hydrocarbons and whether the unique soil bacterial community participates in this process. Also studies have begun to determine whether ecotypes of J. roemerianus have developed in longterm contaminated sites that would be better candidates for cloning plants for use in phytoremediation.
1:30 REMOTE SENSING ALGORITHMS BY NUMERICAL INVERSION OF RADIATIVE TRANSFER MODELS: NEURAL NETWORK AND OPTIMIZATION METHODS COMPARED
David [Hughes.sup.*] (1), R.J. Holyer (1), and Z.P. Lee (2), (1.) University of Southern Mississippi, Hattiesburg, MS 39406, and (2.) University of South Florida, Tampa, FL
The purpose of this research is to conduct the first direct quantitative comparison between two widely used bathymetric tools concerning Case 2 waters. The optimization method and the neural network method are compared using two hyperspectral images (HyMap of Ship Island, Mississippi, and A VIRIS of Tampa Bay, Florida). Both methods attempt to solve the inverse optics problem where the optimization method utilizes forward solutions provided by a semianalytical method and the neural network utilizes HYDROLIGHT. The analysis of the respective inversion procedures and results is accomplished using sensitivity analysis, error distribution analysis, and observations on convergence. The methods are compared on the basis of accuracy, efficiency, robustness, and extension to the aforementioned complex coastal environments. The final product of this research is a quantitative comparison to show the robustness and applicability of the two methods to two varied bathymetry cases. It is shown that the neural network metho d exhibits more robustness and efficiency than the optimization method whereas the optimization method shows greater accuracy for selective images.
1:45 ONTOGENY OF CULTURED LARVAE OF RED SNAPPER LUTJANUS CAMPECHANUS WITH EMPHASIS ON DEVELOPMENT OF THE DIGESTIVE SYSTEM
David [Chiluiza.sup.*], Rena A. Krol, Nancy J. Brown-Peterson, John T. Ogle, and William E. Hawkins, The University of Southern Mississippi, Ocean Springs, MS 39566
During culture of red snapper Lutjanus campechanus, high mortalities occur at 3-5 days post-hatch (DPH) and 17-19 DPH. To investigate this problem, we examined the ontogeny of the digestive system using serial, thin-sectioned tissues and high-resolution light microscopy. Larvae were sampled daily from hatch to 30 DPH, fixed in Bouin's solution, embedded in methyl n-butyl methacrylate medium and sectioned at 1.0 or 2.0 [micro]m. At hatching, the digestive system is composed of a simple straight gut lying dorsal and posterior to the yolk sac. During the first 3 DPH, gut differentiates and all its related organs develop. These changes represent a high-energy demand that the larvae obtained through yolk consumption, which was depleted by day three. From day four onward, morphological changes were mostly related to the increasing size and specialization of organs, and mainly, to the formation of a pseudostomach from the midgut. Morphological characteristics, particularly those related to the ontogeny of the digest ive system, could reflect the quality of red snapper larvae and, therefore, the likelihood of their survival. Knowledge of the development of the digestive system could help to identify when the fish are ready to accept food, to determine the optimal diet, and to find solutions to rearing problems by determining an appropriate ontogenic feeding schedule. (Supported in part by Grant NA86FL0476 from NOAA).
2:00 PATHOLOGY, ECOLOGY, AND TAXONOMY OF BLOOD FLUKES (SANGUINICOLIDAE) FROM HEARTS OF FISHES IN THE GULF OF MEXICO
Stephen A. [Bullard.sup.*] and Robin M. Overstreet, University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39566
Adult blood flukes infect marine and freshwater fishes and are usually reported from the heart, branchial vessels, or mesenteric vessels. Little is known on blood fluke diversity, host ranges, geographic ranges, and pathogenicity. Only four adult sanguinicolids have been reported from 6 Gulf of Mexico fishes, an adult blood fluke has not been described from a Gulf fish in 46 years, none has been described from the northern Gulf west of Mobile Bay, a study on the distribution or seasonality of a blood fluke in a Gulf fish population has not been conducted, and there are few details of wild host-parasite relationships. We examined the vascular system of roughly 1,300 fishes of 153 species, 92 genera, 52 families, and 15 orders from the Gulf of Mexico, Caribbean Sea, Eastern Pacific Ocean, and Western North Atlantic Ocean. Collections included specimens of Selachohemecus sp. from blacktip sharks (Carcharhinus limbatus), Cardicola sp. 1 from red drums (Sciaenops ocellatus), Cardicolasp. 2 from black drums (Pogoni as cromis), a new species in a new genus from red snappers (Lutjanus campechanus), and Psettaroides sp. from cobias (Rachycentron canadum). Drum flukes were collected throughout the year, and most flukes were collected from a single host species. These blood flukes utilize homologous morphological features in different ways and different degrees to attach and locomote within their hosts. We also examined sections of infected tissues to gain insight on the host response to blood flukes. (Supported by NOAA/NMFS No. NA96FL0358 and Mississippi-Alabama Sea Grant Consortium).
2:30 SPECTRAL ANALYSIS OF OBSERVED AND SIMULATED GULF STREAM TRANSPORT IN THE FLORIDA STRAITS
Kevin [McKone.sup.*], (1) Vladimir Kamenkovich (1), Tammy Townsend (2) and Harley Hurlburt (2), (1.) University of Southern Mississippi, Stennis, MS 39529, and (2.) Naval Research Laboratory, Stennis, MS 39529
Multiple methods of spectral and cross-spectral analysis, using both parametric and non-parametric methods, are used to validate signals in observed and simulated Gulf Stream transport time series. Signal strength and frequency of observed transport from cable voltage measurements in the Florida Straits at 27[degrees]N are looked at and compared to the signal strength and frequency of simulated transport time series signals from the Naval Research Laboratory (NRL) Layered Ocean Model (NLOM). Simulated transport time series are taken from the Old Bahama Channel (OBC), transport between Key West, Florida, and Havana, Cuba, Florida Straits at 27[degrees]N, and the Northwest Providence Channel. These time series are short, averaging only 13 years in length. With signals including, but not limited to biennial, seasonal and six month, the problem of choosing a method of signal analysis becomes nontrivial. Qualitative comparisons of signal strength and frequency have been made on individual time series. If all metho ds used show similar strength and frequency for a particular signal, the signal is then taken as real. This same method has also been used to compare signals between time series using a similar qualitative approach with multiple methods of cross-spectral analysis.
2:45 STOMACH CONTENT ANALYSIS OF PINFISH, LAGODON RHOMBOIDES, FROM WIDGEONGRASS BEDS, RUPPIA MARITIMA, IN THE GRAND BAY NERR
Kenneth J. [Brookins.sup.*] (1), Donna Drury (2), and Chet F. Rakocinski (2), (1.) Jackson State University, Jackson, MS 39219, and (2.) University of Southern Mississippi, Gulf Coast Research Laboratory, Ocean Springs, MS 39566
Pinfish, Lagodon rhomboides, were collected from within widgeon grass, Ruppia maritima, in the Grand Bay National Estuary Research Reserve (NERR) in June and July 2001 to evaluate their trophic role. Sampling for fish and available prey in the area were conducted using a seine and a kick net respectively. Water parameters (D.O., salinity, and temperature) were measured using a YSI multiparameter meter. Captured fish ranged in size from 33 mm to 73 mm. A total of nine prey types were observed in the stomachs of the fish; including amphipods, copepods, fish, shrimp, and crabs. Plant material consisting of Ruppia maritima and epiphytes, as well as spartina detritus were also observed in the stomachs. In terms of prey contribution by volume, amphipods (15%-95%) and copepods (35%) dominated. Fish < 50 mm consumed mainly amphipods (55%) and copepods (35%); whereas, fish > 50 mm consumed amphipods (35%) and plant material (40%). This ontogenetic shift from primarily camivorous diet to an omnivorous one is consistent with results of previous studies. Our study suggests that the trophic role of pinfish in widgeon grass beds may be more complex than other investigations have reported.
3:00 THE USE OF CHLOROPHYLL FLUORESCENCE LIFETIME TO ASSESS PHYTOPLANKTON PHYSIOLOGY WITHIN THE MISSISSIPPI RIVER PLUME
Callie M. [Hall.sup.*] (1), Donald G. Redalje (2), Richard L. Miller (1), and Salvador Fernandez (3), (1.) NASA, Stennis Space Center, MS 39529; (2.) University of Southern Mississippi, Stennis Space Center, MS 39529; and (3.) Ciencia, Inc.
Although discrete measurements of phytoplankton carbon fixation provide some of the ancillary information needed for ocean color algorithm development, such measurements are often difficult to make (due to sample manipulation and artefacts common to the procedure) and do not provide real-time information on phytoplankton physiology. Measurements of chlorophyll fluorescence lifetime, however, provide a non-intrusive assessment of phytoplankton photochemical conversion and can be used to estimate parameters directly related to phytoplankton primary productivity. The increased spatial and temporal coverage of chlorophyll fluorescence lifetime measurements, compared to classical incubation-based techniques used to estimate carbon fixation, provides a meaningful snapshot of photosynthetic efficiency within environments which are physically variable at relatively small spatial and temporal scales, i.e., river-dominated environments. Chlorophyll fluorescence lifetime was used to assess phytoplankton photosynthetic e fficiency within the horizontal and vertical mixing gradients within the Mississippi River Plume. Extensive research has addressed the seasonality and magnitude of primary production attributed to Mississippi River outflow within the Gulf of Mexico, but few studies have gauged the photosynthetic efficiency of phytoplankton along this estuarine continuum. Environmental data (nutrient and chlorophyll concentrations, temperature, salinity, and light transmission) were collected during periods of increased and decreased river discharge (spring and fall, respectively) to examine the impact on fluorescence lifetime.
3:15 VARIATIONAL INTERPOLATION METHOD FOR COMPARING CTD OBSERVATION DATA WITH PRINCETON OCEAN MODEL DISTRIBUTIONS OF THE TEMPERATURE AND SALINITY FIELDS IN MISSISSIPPI SOUND
Nadya [Vinogradova.sup.*], Sergey Vinogradov, Dmitri Nechaev, and Vladimir Kamenkovich, University of Southern Mississippi, Stennis Space Center, MS 39520
During 1999-2001 in the course of Northern Gulf of Mexico Littoral Initiative project (NGLI) five CTD surveys were performed in Mississippi Sound. At the same time the distribution of temperature and salinity were calculated using a version of Princeton Ocean Model (PDOM). The goal of this paper is to propose a method that allows comparing these observations and the distribution obtained from modeling. The method of variational interpolation has been proposed, developed and implemented for the analysis of temperature and salinity observations. The interpolation is based on the minimization of the cost function which takes into account the spatial correlations and error variances of the observed fields. The method allows taking into account the influence of coastlines, island boundaries and bottom topography on the correlation structure in the observed fields. A series of experiments have been conducted to tune the statistical parameters of the interpolation. The horizontal distribution for the temperature and salinity fields at two depth layers (0.5-2.0 m and 2.0-4.0 m) has been recovered from the observations on the curvilinear grid of PDOM. Though the interpolation technique was designed for the validation of the model versus the CTD data, the obtaining temperature and salinity distribution and the error observation maps also allow to perform circulation analysis for Mississippi Sound.
3:30 Divisional Poster Session
DETERMINATION OF THE LD50 OF THE TAURA SYNDROME VIRUS (TSV) ON THE SHRIMP, LITOPENAEUS VANNAMEI
Jonathan E. [Watkins.sup.*] (1), Andy Soto (1), and Jeffery Lotz (2) (1.) Jackson State University, Jackson, MS 39217, and University of Southern Mississippi-Gulf Coast Research Laboratory, Ocean prings, MS 39566
Taura Syndrome Virus (TSV) is the most economically significant disease affecting the shrimp industry in the Americas. TSV, first noticed infecting shrimp on farms in Equador and Colombia in the early 1990's, has now spread throughout the shrimp-growing regions of the world. We conducted experiments using shrimp weighing between 2 and 3 g to determine the LD50 of TSV on L. vannamei. In the first experiment 80 shrimp were injected with a cell-free shrimp homogenate containing TSV. The shrimp were divided into groups of twenty and were assigned to treatments of 1:[10.sup.-1], 1:[10.sup.-2], 1:[10.sup.-3], and 1:[10.sup.-4] (w/v) dilutions of tissue from shrimp known to have died of TSV, with distilled water. In the second experiment, the homogenates consisted of a 1:[10.sup.-4], 1:[10.sup.6], 1:[10.sup.8], 1:[10.sup.-10], 1:[10.sup.-12] (w/v) dilutions. We injected the homogenate (0.02 ml/g body weight) into the muscle of the third abdominal segment of each shrimp. Ten L. vannamei were injected with a virus-fre e homogenate of the [10.sup.-4] dilution as negative control for both experiments. Each shrimp was placed in a 1 L jar. The jars were then supplied with an air stone and placed in a water bath maintained at 29[degrees]C. The shrimp were fed and kept in the jars for five days. Shrimp mortality ranged from 100% at 1:[10.sup.-1] virus dilution to 0 at 1:[10.sup.-12] The data suggest that the LD50 of TSV on L. vannamei is about 1:[10.sup.-5].
HEMATOLOGICAL AND SERUM BIOCHEMICAL CHANGES IN CYPRINUS CORPIA IN RESPONSE TO ENDOSULFAN TOXICITY
F. [Jenkins.sup.*] (1), J. Smith (1), B. Rajanna (1), U. Shammem (2), U.D. Kandalam (2), S. Vardhanapu (2), and R. Madhavi (2) (1.) Alcorn State University, Lorman, MS 39096, and (2.) Andhra University, India
Endosulfan, an organochlorine pesticide used extensively as an agricultural pesticide is a known toxin to fish as well as human upon exposure. This study was conducted to investigate effects of endosulfan on hematological and serum biochemical changes and immunosuppressive activities in Carp (Cyprinus carpio) cultured on a large scale in India. Carps were exposed to sub lethal (5 ppb) and lethal (10 ppb) doses of endosulfan for 30 d and 96 h respectively. Blood samples were analyzed for various hematological and serum biochemical parameters. Endosulfan at all concentrations reduced RBC (Red Blood Cells) and enhanced WEC (White Blood Cells) counts. This trend was more pronounced at 14 d.p.e (days after post exposure) and continued till 30 d.p.e. However, the reduction in the hemoglobin and hematocrit values were not significant. Significant reductions in protein, albumin, globulin and enzymes such as; alkaline phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase indicated that the fish was under severe metabolic stress. These results suggest that even a very low concentration of the pesticide may induce alterations in the general hematological profile and serum biochemistry in Carp. (Supported by: NIH/FIC/MIRT #TW00132 and MBRS-SCORE #GM55356)
POROSITY AND TORTUOSITY OF SANDY MARINE SEDIMENTS: FORT WALTON BEACH, FLORIDA
Kenneth J. Curry (1), Conrad W. Curry (2), [Maritza Abril.sup.*] (1) Ann Curry (1), Richard H. Bennett (2), and Matthew H. Hulbert (3) (1.) University of Southern Mississippi, Hattiesburg, MS 39406; (2.) SEAPROBE, Inc., Picayune, MS 39466; and (3.) Research Dynamic Co., West Chester, PA 19380
Diver marine sediment cores were collected off Fort Walton Beach, Florida, and were stabilized on board the research vessel by gently pouring liquid agar into each core and allowing it to solidify. Subsamples were subsequently embedded with Spurr's (ERL 4206) epoxy resin which stabilized the three-dimensional fabric. Porosity was measured using known (measured) densities of the sand grains ([[gamma].sub.s]) and embedding material ([[gamma].sub.p]) using the relation n = ([[gamma].sub.t] - [[gamma].sub.s])/([[gamma].sub.p] - [[gamma].sub.s]) where [[gamma].sub.t] is the bulk density of the sample measured using Archimedes' Principle. Porosity of the marine sediments ranged from 41 to 52%. Tortuosity was determined by sanding and polishing a sediment surface, capturing an image of that surface with incident light from a half-silvered mirror, and using image analysis software to measure the shortest pathway through the pores. Both vertical and orthogonal horizontal aspects were measured for tortuosity. Values of tortuosity in any plane ranged from 1.03 to 1.27. This work was supported by the Office of
PRODUCTION OF A HIGHLY TOXIC SUBSTANCE, TBT, FROM AN INNOCUOUS SUBSTANCE, DBT, IN COASTAL WATERS
Thomas F. [Lytle.sup.*] (1), Julia S. Lytle (1), Steve Manning (1), and William Walker (2), (1.) Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566, and (2.) USEPA, Gulf Breeze, FL
Dibutyltin (DBT) is used in the plastics polymerization process, as catalyst in PVC products and is primary degradation product of tributyltin (TBT), an antifoulant in marine paint. DBT and other organotin compounds make their way into the environment through antifoulants, PVC processing plants, and PVC products maintained in water and water handling systems. A flow-through saltwater lifecycle toxicity test was conducted to determine the chronic effect of DBT to sheepshead minnow (Cyprinodon variegatus Lacepede), an estuarine species. Embryos were monitored through hatch, maturation, growth, and reproduction in concentrations of 158, 286, 453, 887, and 1510 Fg DBT/L. Progeny were monitored for survival as embryos and fry/juveniles, and growth for 30 days post-isolation. Mean length of parental generation fish was significantly reduced on day 30 at concentrations> 887 Fg DBT/L. The lowest observable effect concentration (LOEC), 887 Fg DBT/L, and no observable effect concentration (NOEC), 453 Fg DBT/L, were bas ed on effects on the mean length of parental generation. Fecundity, as egg viability, was significantly reduced at the LOEC. Survival of parental and progeny generation embryos was not significantly affected by concentrations < LOEC. The mean length, wet weight and dry weight of progeny generation juveniles were not significantly affected at concentrations < LOEC. TBT, a ubiquitous impurity in DBT, was also monitored throughout study; chronic effects relative to the measured TBT concentrations reflected a similar response pattern to results of an earlier TBT life-cycle study with C. variegatus and suggest TBT as a likely source of some gross biological effects in this study.
SIZE AND WEIGHT RELATIONSHIPS FOR THE GREEN PORCELAIN CRAB, PETROLISTHES ARMATUS, FROM THE MISSISSIPPI SOUND WITH SOME NOTES ON GROWTH
Kirsten M. [Larsen.sup.*], Christine Trigg, and Harriet Perry, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39566
Petrolisthes armatus is a porcellanid crab commonly found on oyster reefs in the Gulf of Mexico. Interest in this porcellanid crab has increased in recent years due to its migration north along the Atlantic coast. Prior to 1990 records for this species did not exist north of the Indian River, Florida. However, large numbers of this species began appearing in tidal oyster reefs along Georgia in the mid 1990s, and it has since moved into both North and South Carolina. Little information exists on this species and none has been found to date on its morphmetrics. This study examined the morphometric characteristics of P. armatus collected from the Mississippi Sound. Carapace length, carapace width, and weight relationships were determined for 150 crabs held in captivity. Crabs were measured (0.01 mm), weighed (1 mg), and placed in individual habitats until they molted. Molting data were collected on 30 crabs and growth (percent increase in carapace length) was calculated.
DISSOLVED RARE EARTH ELEMENTS IN TWO CONTRASTING FLUVIAL SYSTEMS: THE LOWER MISSISSIPPI RIVER AND THE LOCH VALE WATERSHED
Alan M. Shiller, University of Southern Mississippi, Stennis Space Center, MS 39529
The rare earth elements (REEs) form a unique chemical set wherein the gradual decrease in ionic radius across the series leads to systematic changes in geochemical behavior. The properties of the REEs make them particularly useful tools for inquiring into processes that mobilize elements during weathering and transport. Herein, dissolved REE time series from two very different fluvial systems (the Mississippi River and the Loch Vale watershed) are contrasted. In the lower Mississippi (a large flood plain river), there is enrichment of heavy REEs relative to light REEs and also a significant Ce anomaly. These results are in accord with previous observations of transition elements in the lower Mississippi River which suggested the importance of redox processes within the river system in controlling seasonal concentration variability. In contrast, in the Loch Vale system (a small seasonally snow-covered catchment), both light and heavy REEs show a ~5-fold seasonal variability. In this case, an abrupt increase in REE concentrations occurs during early spring when the beginning thaw flushes organic-rich soil water from the watershed. Overall, the results suggest that the greater pH of the Mississippi (~7.8 versus 6.4 for Loch Vale) may result in the differing REE behaviors of these two systems: redox-affected sorption behavior dominating in the Mississippi and organic complexation dominating in Loch Vale.
PALEOCEANOGRAPHY OF A COOL-WATER CARBONATE RAMP DURING THE PAST 130,000 YEARS Charlotte A. [Brunner.sup.*], David M. Anderson, and Miriam S. Andres, University of Southern Mississippi, Stennis Space Center, MS 39529; NOAA, Boulder, CO 80305; and ETH-
Zentrum, CH-8092 Zurich, Switzerland
The cool-water carbonates of the Great Australian Bight (GAB) were produced by a heterozoan fauna that flourished during the Quaternary, sequestering huge amounts of carbonate on the adjacent slope. The biogenic carbonate was deposited in prograding clinoforms at rates exceeding 50 cm/1000 y, matching or exceeding top rates downslope from large coralgal reefs. Despite the importance of such cool-water carbonate systems to the carbon cycle, the hydrographic conditions that nourished the verdant growth remain poorly known. In this work we examine watermass conditions, specifically paleotemperature, during the last 130,000 years at ODP Site 1127 on the upper slope. Age control is provided by oxygen isotope stratigraphy and AMS [C.sup.14] dating. Paleotemperatures are estimated from planktonic foraminifer assemblages using the Modern Analog Technique. Paleotempertures range from 9[degrees] to 18[degrees]C [+ or -]1.4[degrees]C in the cool season and 12[degrees] to 24[degrees]C [+ or -]1.9[degrees]C in the warm se ason. During the period of vigorous bryozoan mound building of MIS 3, paleotemperatures remained below 14[degrees]C during the austral winter and below 20[degrees]C during the summer. An underlying control, like upwelling, likely affected both paleotemperature and heterozoan production at this time.
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|Title Annotation:||various articles on marine and river ecology|
|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2002|
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