MARINE AND ATMOSPHERIC SCIENCES.
Vicechair: Alan M. Schiller, University of Southern Mississippi
1:00 LESIONS ASSOCIATED WITH THE MONOGENEAN ERPOCOTYLE TIBURONIS ON GILLS OF WILD AND CAPTIVE BONNET-HEAD SHARKS (SPHYRNA TIBURO)
Stephen A. [Bullard.sup.*] , Salvatore Frasca, Jr. , and George W. Benz , (1.) Gulf Coast Research Laboratory, Ocean Springs, MS 39564; (2.) University of Connecticut, Storrs, CT 06269; and (3.) Southeast Aquatic Research Institute, Chattanooga, TN 37401
Gill lesions associated with infection by Erpocotyle tiburonis (Monogenea: Hexabothriidae) on wild and aquarium-held bonnethead sharks (Sphyrna tiburo [Carcharhiniformes: Sphyrinidae]) were compared using light and scanning electron microscopy. Four wild sharks each had 3-11 widely-dispersed adult specimens of E. tiburonis, and 1 of the sharks hosted a juvenile specimen. Lamellae near adult specimens of E. tiburonis were pushed aside or bent, but otherwise similar to those of normal filaments. Two aquarium-held sharks each had hundreds of juvenile and adult specimens of E. tiburonis. In these cases, lamellae were in disarray but otherwise normal near juveniles, while a thick layer of hyperplastic epithelium both filled spaces between lamellae and partially or completely covered lamellae near adults. The intense captive infections of E. tiburonis caused severe hyperplastic lesions that probably caused the death of the sharks by reducing or blocking respiratory water flow over lamellae and by reducing both gas eous and ionic exchanges across the lamellar epithelium. However, the wild sharks had relatively minor lesions, suggesting a benign wild parasite-host relationship. Support from Mississippi Alabama Sea Grant Consortium (MASGC) and NOAA/NMFS No. NA86FL0476.
1:15 RELATIVE SUSCEPTIBILITY OF LITOPENAEUS VANNAMEI (KONA STOCK) TO WHITE SPOT SYNDROME VIRUS AND TAURA SYNDROME VIRUS
M. Andres [Soto.sup.*], Virginia Shervette, and Jeffrey M. Lotz, University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39566
We used an experimental procedure that is based on a mathematical epidemiology model to study the survival rate of Litopenaeus vannamei from exposures to white spot syndrome virus (WSSV) and Taura syndrome virus (TSV). The experimental procedure involves exposing 12 susceptible shrimp to a single infected shrimp cadaver for a specified period of time, and then isolating the exposed shrimp individually to determine the number of infections and deaths. In this study, susceptible shrimp are exposed to the infected cadaver for 14 h and isolated for five days. The L. vannamei used in the experiments are from the original unselected population of shrimp (Kona stock) that have been maintained by the United States Marine Shrimp Farming Program. In experiment one, the mean survival rate from a WSSV exposure was 0.55, and from a TSV exposure was 0.52. In experiment two, the mean survival rate from a WSSV exposure was 0.60, and from a TSV exposure was 0.62. A statistical difference was not detected in final mean surviv al rates between the WSSV and TSV exposed groups from either experiment (chi-square test). In both experiments, for the WSSV exposed shrimp, most animals died between 24 and 48 h post-exposure, and for the TSV exposed shrimp, most animals died between 48 and 96 h post-exposure. Our results suggest the original unselected population of L. vannamei are as susceptible to TSV as to WSSV.
1:30 EXPERIMENTAL INFECTION OF THE BLUE CRAB (CALLINECTES SAPIDUS) WITH WHITE SPOT SYNDROME VIRUS: EVALUATION OF WATERBOURNE TRANSMISSION
Charles H. FLowers, Jr. [*], Jeffrey M. Lotz, and Verlee Breland, University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39566
White Spot Syndrome Virus (WSSV) has been devastating to shrimp aquaculture in Asia well as North and South America. Because WSSV is quite virulent in penaeid shrimp and has a wide host range, we undertook to evaluate the susceptibility of wild caught blue crabs (Callinectes sapidus) to infection with WSV. Blue crabs were collected in bayous near Ocean Springs, MS. This experiment examined three variables: infectivity and mortality differences between sexes, and water-borne transmission. Crabs were retained individually in baskets with plexiglass lids and fine meshed nylon sacks on the exterior of the baskets. These sacks were introduced to inhibit particulate matter from traveling from basket to basket. Six baskets were placed in each of four 1900-L tanks. Into the baskets of each tank were placed three males and three females (one crab per basket) of comparable size (120-150mm carapace width). Two males and two females in each tank were fed one moribund Litopenaeus vannamei each, once a day for five days. The feeding ratio for this trial was approximately 5% M:M. The remaining male and female in each tank were fed specific-pathogen free (SPF) L. vannamei with their cephalothoraces separated from their abdomen to allow for ease of predation. The feeding ratio for clean shrimp to crabs was equivalent to the per os viral treatment. Confirmation of WSSV infection was accomplished through the use of polymerase chain reaction (PCR), histology, and bioassay. This research was funded in part by the United States Department of Agriculture/CSREES grant #98-38808-6019.
1:45 THE EFFECTS OF SALINITY STRESS ON SURVIVAL OF NAIVE AND CHRONIC, TAURA SYNDROME VIRUS INFECTED SHRIMP (LITOPENAEUS VANNAMEI)
Lesber F. [Salazar.sup.*], M. Andres Soto, and Jeffrey M. Lotz, University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39566
Taura syndrome virus (TSV) is one of the most important shrimp viruses affecting farmed shrimp in the Western Hemisphere. Infected shrimp go through an acute phase in which most mortality is observed. In the ensuing chronic phase shrimp remain infected but otherwise appear normal. If chronically infected shrimp resume normal functions they should be as likely to survive a stress test as naive shrimp. Therefore we undertook this study to determine if chronically infected shrimp can withstand salinity shock as well as naive shrimp. All shrimp were obtained from the SPF program of the United States Marine Shrimp Farming Program. Chronically infected shrimp were shrimp that had survived a previous TSV laboratory per os challenge. Two experiments were conducted that compared survival of chronically infected and naive L. vannamei subjected to different salinity shocks. In the first experiment, shrimp were transferred from tanks containing 24 ppt seawater individually into jars containing either 6, 12, 18, or 24 pp t seawater. The second experiment consisted of transferring chronically infected and naive shrimp from 24 ppt into seawater of 0, 3, 6, 12, and 24 ppt. In both experiments there was a statistically significant difference in survival between chronically infected and naive shrimp at the salinity shock of 6 ppt. (Pearson Chi-square test, [alpha] = 0.05). These results suggest that chronically infected shrimp are not as likely to resist stress as naive shrimp.
2:00 RESPONSE OF MARSH PLANTS TO CD-SPIKED SEDIMENTS: EFFECTS ON SITE PARTITIONING EFFECTS OF METALS AND BIOAVAILABILITY
Thomas F. [Lytle.sup.*] , Krystal Gage , Nicole Housley , and Julia S. Lytle , (1.) Gulf Coast Research Laboratory, Ocean Springs, MS 39566; (2.) Mississippi State University, Mississippi State, MS 39762; and (3.) University of Mississippi, Oxford, MS 38677
A study was initiated to determine how the dominant saltmarsh macrophytes, Juncus roemerianus and Spartina alterniflora respond to coastal sediments that have been contaminated with Cd. Cd contamination at one site for each plant was effected by addition of Cd to surface sediments. Leaves and sediments were collected after two months (winter) and seven months (summer) and analyzed for Cd with sediments analyzed to determine how much Cd was distributed in sediment fractions, each possessing varying degrees of bioavailability. During winter, Cd in sediments under Spartina and Juncus locates primarily in Fe oxide fraction (reducible) in contrast to primary location in Mn oxide fraction (easily reducible) of controls, but during ensuing active growth months much of the Cd migrates to Mn oxide fraction. Compared to large amplification of Cd in all fractions of sediments for Juncus and Spartina occurring seven months after Cd enrichment, very little difference is seen in amount of Cd uptaken in leaves of either pl ant species. Significant amounts of Cd are relocated to organic fraction of sediments underlying Spartina after seven months (not observed with Juncus). It appears that these marsh plants do play a major role is establishing the distribution of Cd and consequently the bioavailability in sediments and in a way unique to each species.
2:30 POTENTIAL FOR USE OF JUNCUS ROEMERIANUS FOR PHYTOREMEDIATION OF COASTAL SEDIMENTS CONTAMINATED WITH PETROLEUM HYDROCARBONS
Hernando C. Payne [II.sup.*] , Larry Stewart , Thomas F. Lytle , and Julia S. Lytle , (1.) Jackson State University, Jackson, MS 39217; (2.) California Institute of Technology, Pasadena, CA; and (3.) Gulf Coast Research Laboratory, Ocean Springs, MS 39566
Polynuclear aromatic hydrocarbons (PAH) are one of the most common sources of coastal contamination resulting from petroleum products and combustion byproducts. To remedy this problem in an economically efficient manner, environmental agencies need to know if marine plants can assist in the clean-up of these contaminants in marine sediments and water by the process called phytoremediation. A field study was designed to determine uptake ability of PAHs by the dominant Gulf estuarine plants Juncus roemerianus and Spartina alterniflora. Four sites were selected that represented various levels and histories of PAH contamination: a Department of Defense site in Biloxi, a harbor site with long history of various types of contamination, a site spiked with used motor oil to represent a very recent episode of PAH contamination, and a site which served as a control. Leaves, roots, and underlying sediments were analyzed for aliphatic and aromatic hydrocarbons. Though there was evidence of uptake into leaf tissues of hy drocarbons by both plants, J. roemerianus was quite remarkable in having hydrocarbons in leaves with both the distribution and even higher levels of the entire suite of aliphatic hydrocarbons than that found in the sediments. There is good evidence that this marsh plant holds great promise as a candidate for phytoremediating petroleum contaminated sites.
2:45 GEOGRAPHIC VARIATION IN EGG DIAMETER AND FECUNDITY OF BLUE CRAB CALLINECTES SAPIDUS
Lori C. [Hill.sup.*], Kristin N. Ealy, and Patricia M. Biesiot, University of Southern Mississippi, Hattiesburg, MS 39406-5018
Previous work in our lab has shown seasonal variation in egg diameter of blue crabs from Mississippi. The present study was conducted to determine if egg diameter and fecundity varied within this species over its range in U.S. waters. Ovigerous crabs were obtained during summer 2000 from coastal sites in Louisiana, Mississippi, Florida, South Carolina, North Carolina, Maryland, and Delaware. Crabs were similar in size as determined by carapace width. Egg diameters were measured using video microscopy, and fecundity was estimated using a direct count/dry weight method. The diameter of blue crab eggs ranged from 243 to 309 [micro]m, with an overall mean of 268[+ or -]21 [micro]m. Although mean egg diameter was greatest for crabs from the west coast of Florida (282[+ or -]22 [micro]m) and least for crabs from Mississippi (258 [micro]m), these were not statistically significant differences. There was no apparent relationship between egg diameter and fecundity. Fecundity ranged from 1,557 X [10.sup.3] to 6,168 X [10.sup.3] eggs per crab with a mean of 2,871 X [10.sup.3]; larger females exhibited greater fecundity. Mean fecundity was greatest for South Carolina crabs (4,319 X [10.sup.3]) followed by Mississippi (3,885 X [10.sup.3]) and Louisiana (3,014 X [10.sup.3]. Although variations in egg diameter and fecundity occur among blue crabs from different states, the variations are not predictable and likely do not indicate geographic influence.
3:00 BEHAVIORAL EFFECTS OF INDUCED SPAWNING IN TILAPIA, OREOCHROMIS NILOTICUS
Shawanda R. [Wilson.sup.*] and Michael D. Porter, Mississippi Valley State University, Indianola, MS 38741
Experiments were performed to determine if visual cues, olfactory stimulation, or a combination of both is involved in inducing spawning of Tilapia. Two possible hypotheses for the outcome of these experiments are 1) olfactory stimulation will cause the females to ovulate, or 2) both visual cues and olfactory stimulation will cause the females to ovulate. Three tanks were set up side-by-side with dividers placed between them. A filter is set up to allow water to circulate between tanks two and three as to permit water containing pheromones secreted from a male to enter the female's tank. The divider is removed from between tanks one and two to allow visualization of a male during an experimental trial. The fish are then arranged so that the female is always in the middle tank (tank 2) and the males, one of which produces milt and one that does not, are in the other two (tanks 1 and 3) being alternated every two to three trials. HCG is pipetted onto the gills of the females and the male that is producing milt . MS-222 is used as an anesthesia to calm the fish when the hormone is given. The male that is not producing milt is isolated in a dark room after every trial to suppress milt production. Females are exchanged after every trial with at least a month break between trails.
3:15 THE EFFECT OF DIFFERENT HARVEST VOLUMES ON CALANOID COPEPOD CULTURES
Jason T. [Lemus.sup.*], John T. Ogle, and Jeffrey M. Lotz, University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39566
Calanoid copepods from the Mississippi Sound waters have been cultured using the brown water technique in which half the water volume of a zooplankton culture tank is removed and replaced every other day while harvesting copepods. It was assumed that the proportion of harvested copepods was equal to the proportion of water volume removed. Four harvest levels (0%, 25%, 50%, and 75%) were used to determine the effects of harvesting on copepod populations and harvest yields over a 16-day period. Harvested copepods in the range of 23 [micro]m to 125 [micro]m were preserved and counted, while the remaining copepods were returned to the tanks. Each day, 4 g of rice bran was added to all the tanks. The copepod population of each treatment was estimated. The mean copepod yield for each treatment on each harvest day was calculated. Naupliar density and adult density were significantly greater in the 0% treatment than the 50% and 75% treatments. Adult density was significantly greater in the 25% treatment than the 50% and 75% treatments and 50% was significantly greater than the 75% treatment. There were significantly more copepods harvested in the 50% and 75% regimes than the 25%. The 50% and 75% regimes did not differ significantly from each other. Naupliar and adult density decreased with increasing exploitation levels, whereas copepod yield increased with increasing harvest rate. A 75% harvest of one tank would produce the most copepod nauplii; however, harvesting 25% of 2.24 tanks to every one tank harvested at 75% would be more cost effective.
3:30 Divisional Business Meeting
3:45 Divisional Poster Session
A TECHNIQUE FOR PROCESSING UNDISTURBED MARINE SAND SEDIMENTS
Maritza [Abril.sup.*] , Jana B. Avant , Kenneth J. Curry , Richard H. Bennett , and Matthew H. Hulbert , (1.) University of Southern Mississippi, Hattiesburg, MS 39406; (2.) SeaProbe, Inc. Picayune, MS 39466; and (3.) Research Dynamic Co., West Chester, PA 19380
A study of sediment pore fluid pathways and porometry require an "undisturbed" sediment sample for analysis. To preserve the interstitial organic material and the in situ structure, agar infiltration was employed. Cores were collected and placed in a water bath at 55[degrees]C for 45 minutes. Subcores within the main core were infiltrated with liquid agar for 1 to 2 h, followed by a cooling at room temperature. Once the agar solidified it held the sand particles together avoiding disturbances that would be created by subsequent processing. Annotations were made on the position and the physical-chemical parameters. Plugs of 1 cm were taken from the subcores for fixation and plastic embedding. These plugs were fixed in formaldehyde, dehydrated in an ethanol and propylene oxide sequence, and embedded in ERL 4206 epoxy resin (Spurr's). Sediment samples so processed were used for the study, reconstruction and quantification of the two and three dimensional microfabric.
DIURNAL AND NOCTURNAL ACTIVITY BUDGETS OF CAPTIVE BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)
Rachel [Thames.sup.*] and Stan Kuczaj, University of Southern Mississippi, Hattiesburg, MS 39406
Behavioral observations were taken from nine captive bottlenose dolphins over an 8-week period to estimate their activity budgets over a 24-hour day. Instantaneous samples on individual dolphins were taken every minutes throughout the course of a day. Behaviors were expected to be influenced by time of day and age. Observed behaviors were placed into one of five categories: swim high, swim low, play high, play low, and rest. Preliminary data analyses suggest that dolphin behavior is influenced by these factors.
EXAMINATION OF SURFACE GRADIENTS OF DISSOLVED OXYGEN IN AQUACULTURE PONDS
Tracy A. [Thurmond.sup.*] and Michael D. Porter, Mississippi Valley State University, Itta Bena, MS 38941-1400
This project involves comparing patterns in night-time dissolved oxygen levels in commercial catfish (Ictalurus punctatus) ponds. The study examines the role of wind in relation to the orientation of the ponds to see if there are any effect on oxygen distribution. It examines eight ponds during the months of August and September. Oxygen levels were checked on opposite ends of each pond at 2 hour intervals over a 12 hour period. Geographic Information System (GIS) will be used to analyze the data. The interaction of wind with pond dissolved oxygen will be analyzed.
THE EFFECTS OF SUBSTRATE STRUCTURAL COMPLEXITY ON TWO POPULATIONS OF STONE CRABS (MENIPPE ADINA) FROM OYSTER REEFS IN THE MISSISSIPPI SOUND
Daniel [Bass.sup.*] and Harriet M. Perry, Cooperative Intern Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553 and Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39564
The stone crab, Menippe adina, is commonly found in northern Gulf waters and is associated with rock jetties and oyster reefs. Structural complexity and niche availability have been found to affect size frequency of stone crab populations. Stone crab populations from two reefs with different relief were examined to determine abundance and size class differences. The two reefs were located in Mississippi Sound approximately 25 miles apart and differ in age and structural complexity. Stone crab populations were sampled using artificial habitats. Habitat samplers were filled with oyster shell, placed on the reefs, and allowed to soak for three months. Samplers were retrieved, returned to the laboratory and stone crabs removed and frozen. Sex, carapace width ([+ or -] 0.02 mm), and weight ([+ or -] 0.001 g) were determined. The abundance and size frequencies of the crabs were compared between the two reefs (Student's t-test, [alpha] = 0.05) to examine the effects of structural complexity on the composition of th e stone crab populations.
USE OF ESTUARINE VEGETATION FOR PHYTOREMEDIATING CD-CONTAMINATED WATERS
Thomas F. [Lytle.sup.*] , Nicole Housley , Krystal Gage , and Julia S. Lytle , (1.) Gulf Coast Research Laboratory, Ocean Springs, MS 39566; (2.) University of Mississippi, Oxford, MS 38677; and (3.) Mississippi State University, Mississippi State, MS 39762
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. To determine whether freshwater and brackish plants will translocate metals into their tissues and produce these sequestering compounds, we tested Najas guadalupensis, a submerged non-rooted and Bacopa monnieri, a rooted plant by placing them into plastic containers and exposing them to Cd levels of 0, 0.1 and 1.0 ppm. During 12 intervals covering five days including a 1 day depuration period, plants were removed and examined for Cd levels. Najas guadalupensis removed significantly more Cd in less time than did the B. monnieri, though the latter retained the Cd in tissues much longer than did the N. guadalupensis parti cularly at the 1 ppm exposure level. Results suggest that examination of very hardy submerged and rooted plants that be readily cultured and resist toxic effects of Cd may be of value in considerations of plant candidates for cleaning up coastal ponds or other enclosed waters with Cd contamination.
UPTAKE OF CADMIUM AND CHROMIUM BY JUNCUS ROEMERIANUS
Julia S. [Lytle.sup.*] , Roshunda Sample , and Thomas F. Lytle , (1.) University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39564 and (2.) Jackson State University, Jackson, MS 39217
Gulf coastal sediments, particularly estuarine sediments, contain elevated levels of heavy metals, some of which are toxic. Studies have shown that some agricultural plants take up and accumulate heavy metals, but it is not known whether coastal marsh plants can accumulate metals in their tissue. Phytoremediation, a natural process by which plants remove contaminants from sediments and waters, may be an alternative process for removing metals from coastal waters and sediments. A laboratory study designed to assess uptake of cadmium and chromium by Juncus roemerianus, Mississippi's most dominant tidal marsh plant, indicated that this species bioaccumulated twice the concentration exposure levels of chromium and five times the concentration levels of cadmium in seven days. Total glutathione and peroxidase activity were measured to evaluate the plants' response to oxidative stress. Glutathione levels increased in a dose response manner when exposed to chromium but decreased when exposed to cadmium. Results of t his experiment can be used to help determine if J. roemerianus can be used in cleaning up metal contamination in coastal sediments.
UPTAKE OF HEAVY METALS BY SPARTINA ALTERNIFLORA
Julia S. [Lytle.sup.*] , Valencia A. Payne , and Thomas F. Lytle , (1.) University of Southern Mississippi, Institute of Marine Sciences, Ocean Springs, MS 39564 and (2.) Jackson State University, Jackson, MS 39217
Phytoremediation is a process using plants to remove contaminants from sediment, air or water. Though it is well known that many agricultural plants take up contaminants from soils, little is known regarding the uptake capability of coastal plants. A laboratory study was designed to assess the ability of Spartina alterniflora to take up Cd, Pb, Ag, Cr, and Cu from water. Peroxidase activty (POD) was measured on days two and eight to assess the ability of S. alterniflora to handle oxidative stress. Four replicate microcosms, each containing 12 plants, were prepared for each of the five metals tested and four replicates were prepared as test controls. Test solutions were prepared in Hoagland's solution to contain 1 ppm metal concentrations. On days two and eight, half of the plants in each microcosm were collected and analyzed for heavy metals and POD. Heavy metal analysis was made using atomic absorption spectrophotometry and POD analysis was measured using UV/Visible spectrophotometry. One replicate microcos m from each treatment was evaluated for biomass. Biomass decreased in all metal treatments except chromium, and chromium biomass increased. Plants in the silver treatment lost significantly more biomass than those of the other metal treatments. Uptake of cadmium was small on day two but increased significantly from day two to day eight when it accumulated 16 times the exposure concentration. Chromium elicited both the strongest POD and glutathione response. Spartina alterniflora took up 16 times the exposure concentration of both cadmium and copper in eight days and may be a possible candidate for phytoremediation of heavy metals.
HABITAT RECORDS OF SOME FISH SPECIES IN THE VICINITY OF MISSISSIPPI SOUND
Sonya D. [Barner.sup.*], Sara E. LeCroy, and Chet F. Rakocinski, University of Southern Mississippi, Gulf Coast Research Laboratory Campus, Ocean Springs, MS 39566-7000
To generate museum records and document biodiversity in Mississippi coastal waters, fishes were collected from various habitats in Mississippi Sound and nearby Gulf of Mexico waters, ranging from Fort Bayou inshore waters to open waters near Horn and Chandaleur Islands. Samples were collected with seines and an otter trawl. Fishes were sorted, identified, catalogued and deposited in the fish museum at Gulf Coast Research Laboratory (GCRL). The GCRL Museum database was searched to provide additional information on the five most abundant species from each habitat in order to compare fish habitat preferences for the most common species collected. Forty species of fish were identified. The following families had the highest number of species: Carangidae (5), Fundulidae (5), Sciaenidae (5), Engraulidae (3) and Sparidae (3), followed by the Clupeidae (2), Gobiidae (2), Mugilidae (2), Synodontidae (2) and Syngnathidae (2). Of the seven species collected at the Fort Bayou station, Menidia beryllina, Anchoa mitchilli , and Lucania parva were the most abundant accounting for about 76% of the total catch. In the offshore areas of Barrier islands, eleven species were collected with Anchoa hepsetus, A. mitchilli, and Saurida brasiliensis being the most abundant. Two different distribution patterns were evident based on our collections. Pelagic forage species such as Anchoa mitchilli and Menidia beryllina were widespread, showed no apparent habitat association and were euryhaline, occurring widely throughout the area. The second pattern was shown by species that were associated with one or two habitat types. These included Sauridia brasiliensis, Eutremeus teres, and Stenotomus caprinus, which were collected only at the open water stations, Gobiosoma bosc, from low salinity mud bottoms, Trachinotus carolinus and Menticirrhus americanus from nearshore sand bottoms, and all three species of Fundulus, Oligoplites saurus, and Eucinostomus argenteus from high salinity grassbeds.
RELATIONSHIP BETWEEN THE FLUORESCENCE LIFETIME OF CHLOROPHYLL A AND PRIMARY PRODUCTIVITY WITHIN THE MISSISSIPPI PLUME AND ADJACENT SHELF REGION DURING HIGH- FLOW AND LOW-FLOW CONDITIONS
Callie M. [Hall.sup.*] , R.L. Miller , S.M. Fernandez , and B.A. McKee , (1.) NASA, Geospace Applications and Development Directorate, Stennis Space Center, MS 39522; (2.) Ciencia, Inc.; and (3.) Tulane University, New Orleans, LA 70118
In situ measurements of chlorophyll fluorescence intensity have been widely used to estimate phytoplankton biomass but provide little information on the physiological state of the phytoplankton under study. Lifetime-based measurements of chlorophyll fluorescence, however, provide a framework in which photosynthetic rates of phytoplankton can be analyzed according to phytoplankton physiology. Within photosynthetic organisms, high chlorophyll a lifetimes correspond to low photochemical efficiency and low chlorophyll a lifetimes correspond to high photochemical efficiency. Along with the measurement of primary production and ambient nutrient concentrations within the Mississippi River plume in the northern Gulf of Mexico, phytoplankton fluorescence lifetimes were measured using a Fluorescence Lifetime Phytoplankton Analyzer (developed under a NASA Small Business Innovative Research contract to Ciencia, Inc.). The extent to which nutrient and effluent loading within this dynamic coastal region affect the photosy nthetic performance of phytoplankton, especially during low-flow and high-flow conditions of the Mississippi River, will be presented as a function of phytoplankton fluorescence lifetimes. Comparisons will be made between the relationship of phytoplankton primary productivity and chlorophyll a fluorescence lifetime during high and low discharge of the Mississippi River to the plume environment. Differences between chlorophyll a fluorescence lifetime and between primary productivity measured during the two flow regimes will be discussed also.
9:00 SIMPLE SYRINGE FILTRATION METHODS FOR FIELD FILTRATION OF DISSOLVED TRACE ELEMENT SAMPLES
Alan M. Shiller, University of Southern Mississippi, Stennis Space Center, MS 39522
Adequate sample filtration is an important aspect of sample processing for dissolved trace element analysis. Inadequate filtration can be responsible for improperly high results. There have been debates in the literature about filtration protocols as well as defining the dissolved phase. Here I examine the use of both 0.45 [micro]m polyethylene and 0.02 [micro]m alumina syringe filters. Even for river water it appears that these filters can be properly cleaned for dissolved trace element sample processing. The use of all-poly syringes is also required. While only small ([sim]10-15 mL) samples are obtained by this method, the use of highly sensitive analytical techniques such as high resolution ICPMS allows quantification of many dissolved trace elements even at the low ppt level.
9:15 THE NORTHERN GULF OF MEXICO LITTORAL INITIATIVE (NGLI): A COLLABORATIVE MODELING, MONITORING, AND RESEARCH EFFORT
Vernon [Asper.sup.*] , John Blaha , Carl Szczechowski , Craig Cumbee , Bob Willems , Steven E. Lohrenz , Donald Redalje , and Arne-R. Diercks , (1.) University of Southern Mississippi, Stennis Space Center, MS 39529; (2.) U.S. Naval Oceanographic Office, Stennis Space Center, MS 39529; and (3.) Ocean Technologies, L.L.C., Pass Christian, MS 39571
The objective of the NGLI project is the implementation and testing of a circulation, sediment, and wave modeling system for the Mississippi Sound and adjoining rivers, bays, and shelf waters. The final product will be a system which can be utilized by local, state, and federal agencies for a variety of purposes that deal with military training, research into littoral processes, resource management planning, maximum nutrient loads, and the possible contamination of coastal waters, rivers, and beaches. In order to develop and refine this modeling system, a suite of in situ data is required, including the circulation, optical quality and physical characteristics of the water along with important atmospheric parameters such as wind speed and direction, rainfall, humidity, and barometric pressure. These parameters are being measured by an expanding suite of sensor systems, some of which relay their observations in real time to a data collection system at NAVO. The installation and maintenance of these sensors re presents a substantial investment of both funds and effort, and will be discussed along with a presentation of the first data sets to be produced.
9:30 VALIDATION OF MODAS-NRLPOM FORECASTING SYSTEM
Germana [Peggion.sup.*] and Daniel N. Fox, University of Southern Mississippi, Stennis Space Center, MS 39522
A scalable, rapidly relocatable version of the Princeton Ocean Model has been implemented to provide short term (2 day) forecast applications in support of real-time naval operations. The simulations are initialized with temperature and salinity fields generated by the Modular Ocean Data Assimilation System (MODAS) which uses optimal interpolation to assimilate scattered profiles into a first guess field using remote sensed data. MODAS has proven to be a valuable tool in deep and open areas where a high correlation exists between surface and subsurface flow. In coastal areas the correlation is week and MODAS nowcast may lack accuracy. We will present the results of 3 real-time exercises in 3 different coastal domains. 1) off the NJ coast in support of the LEO- 15 program (where a large amount of in situ were available); 2) the Northeastern Gulf in support of the FBE-H naval exercise off Panama City, Fla. (where few data were collected), and 3) the Monterrey Bay, Ca in support of the Bioluminescence field pro gram (no in situ data). All the cases have been configured with some nesting/coupling procedures between: 1) existing real-time large-scale models (such as POM in North Pacific and NCOM-global) and 2) 1-way nesting between domains of different resolutions. The coupling/nesting procedure will also be presented and discussed.
9:45 COMPARISON OF MOS FORECASTS AGAINST HIGH-RESOLUTION FORECASTS
Darryl [Nash.sup.*], Laurita Brown, Frederick Howard, and Pat Fitzpatrick, Jackson State University, Jackson, MS 39217
The Northern Gulf of Mexico Littoral initiative (NGLI) is an initiative sponsored by the U. S. Navy with participation from several companies and universities including Jackson State University. The purpose of this initiative is to implement, verify, and test a circulation-sediment-wave modeling system for the Mississippi sound, bays, and shelf waters. The goal of (NGLI) is to develop an improved, high-resolution forecast suite in support of troop developments in costal (littoral) regions. The tools currently being used to assist in these predictions are Nested Grid Model (NGM) coupled with Model Output Statistics (MOS), which are considered to be the benchmark standards. The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) is a high-resolution forecasting tool developed by the Navy. COAMPS was designed to run at a higher resolution than MOS and is thought to provide more accurate forecasts than its predecessor. The purpose of our experiment is to examine whether COAMPS is the more accurate of t he two forecasting systems. We plan to accomplish this by deploying a COAMPS model at predetermined sites along the Northern Gulf of Mexico Littoral Region. The data from our COAMPS model will be plotted against data generated from MOS models. Both models will then be compared against observed conditions to determine accuracy. It is our hypothesis that COAMPS will prevail as the more accurate of the two weather forecasting systems.
10:15 EXAMINATION OF INHERENT OPTICAL PROPERTIES, BIOGEOCHEMICAL CONSTITUENTS AND PHYSICAL PROPERTIES IN SOUTHEASTERN LAKE MICHIGAN DURING STRATIFIED CONDITIONS
Amy G. [Brown.sup.*] , Steven E. Lohrenz , and Gary L. Fahnenstiel , (1.) University of Southern Mississippi, Stennis Space Center, MS 39529 and (2.) Great Lakes Environmental Research Laboratory, Muskegon, MI 49440
Evaluation of remote sensing algorithms in coastal and lake waters is limited by a paucity of in situ optical and biogeochemical data. This study is the first to examine the relationship between physical properties, inherent optical properties (spectral absorption and scattering), and dissolved and particulate constituents (e.g. SPM, Chl a, and CDOM) in southeastern Lake Michigan. Our study was conducted in the outflow region of the St. Joseph River during the stratified period in June, 1999. Our results demonstrated that the river is a potential source of horizontal gradients between near shore and offshore stations, and contributed to a localized area of distinct bio-optical properties. The results of this study will be used to refine estimates of subsurface irradiance for modeling primary production and will contribute to a database for validation of ocean color algorithms for estimation of algal biomass and other constituents in this lake ecosystem.
10:30 A STUDY OF THE RELATIONSHIP BETWEEN LONGSHORE/OFFSHORE BAR DEPTH AND DISTANCE FROM THE SHORE
Cynthia M. [Fiallos.sup.*] and Peter Fleischer, Naval Oceanographic Office, Stennis Space Center, MS 39522
Although the dynamics and morphology of offshore/longshore bars have been studied extensively, bar depth as function of distance from the shore is generally ignored. Knowing bar depth with respect to distance from shore, as well as the seasonal and tidal variables affecting bars, is advantageous when navigating vessels to the beach, and for conducting amphibious operations. We
have compiled and analyzed data from the literature in order to determine what relationship exists between the depth of longshore/offshore bars and distance from the shore in various environments and seasons. Regression equations were calculated for data subsets as well as for combined data from various environments and seasons. The combined, full data set has a linear regression of y = 0.66 + 0.0071x ([R.sup.2] = 0.62), which best describes the relationship between bar depth and distance from the shore. From limited data, it appears that bar depth and distance from shore diminish during spring. The effect of tidal range upon bar depth , the magnitude of seasonal variation, and type of coast require additional data to establish confidence in any relationships.
10:45 HIGH FREQUENCY COASTAL RADAR (CODAR) SURFACE CURRENT MEASUREMENTS IN THE MISSISSIPPI SOUND
Ame-R. [Diercks.sup.*] , Charles Riley , Kim Pettway , and Don Barrick , (1.) Ocean Technologies, L.L.C., Pass Christian, MS 39571 and (2.) CODAR Ocean Sensors, Ltd., Los Altos, CA 94024
Two 25 MHz CODAR high frequency (HF) radar systems have been installed along the coast of the Mississippi Sound to acquire synoptic real time surface currents in coastal waters at a spatial resolution of one square kilometer. At over 500 grid points, current vectors are derived hourly in real time to produce surface current maps. Installation, operation and maintenance of these HF radar systems represents a substantial investment of both funds and effort. Concepts, operation and first results of these two shore-based CODAR systems will be presented. Objectives of the HF radar operations include the contribution of boundary data to the Northern Gulf of Mexico Littoral Initiative (NGLI) modeling system in the Mississippi Sound, and establishment of a database of high resolution surface currents. Long term surface current data can aid in tracking contaminants, trace their origin, and help in other environmental and research related objectives.
11:00 HIGH-RESOLUTION RECORD OF LATEST QUATERNARY PALEOCEANOGRAPHY IN THE GREAT AUSTRALIAN BIGHT
Charlotte A. [Brunner.sup.*] and Miriam S. Andres, University of Southern Mississippi, Stennis Space Center, MS 39529 and Geological Institute, ETH-Zentrum, Sonneggstr. 5, CH-8092, Zurich, Switzerland
An enormous temperate-water, carbonate reef has dominated the structure of the continental margin of the Great Australian Bight (GAB) since the late Eocene. The bryozoan reef growth flourished in particular during the large fluctuations in Quaternary sea level, which sculpted redeposited reef carbonate into thick seismic sequences within the outer reef and adjacent reef and continental slope. Sediment accumulated at a stunning rate near 1 m/k.y. on the shelf edge and upper slope, where Quatemary-age sequences exceed 500 m in thickness. Despite the evident volumetric importance of temperate reef systems, such as the GAB, to burial of carbon, the nature and growth of temperate-water bryozoan reefs and reef slopes remain poorly known. In this study, the latest Quaternary sections of two ODP holes from the shelf edge (200 m water depth) and slope (700 m water depth) were examined in detail to determine the paleoceanographic conditions that modulate carbonate production in the GAB bryozoan reef. Assemblages of pl anktonic foraminifers, stable carbon and oxygen isotope anomalies, sedimentation rates, and other proxies of seawater properties were evaluated to determine the conditions that spurred periods of fastest carbonate production. Preliminary results suggest that strong, episodic upwelling stimulated production at the shelf edge during marine oxygen isotope stage 3.
11:15 CORAL REEF ECOSYSTEMS OF BELIZE
Christopher [Simmons.sup.*] and Gary Gaston, University of Mississippi, University, MS 38677
Coral reef ecosystem off the coast of Belize, located around South Water Caye, is studied in terms of and pertaining to coral reef ecology. Reef ecosystem surrounding South Water Caye is studied and surveyed using a patch reef acquisition method. Aspects of physiology, morphology/behavior, and sex change/mating systems are studied and described using the tropical marine fish of the coral reef ecosystem.
1:00 FEEDING HABITS OF JUVENILE POMPANO (TRACHINOTUS CAROLINUS) COLLECTED FROM THE EASTERN GULF OF MEXICO
Kersten N. [Wheeler.sup.*], Richard W. Heard, and Chet F. Rakocinski, University of Southern Mississippi, Gulf Coast Research Laboratory Campus, Ocean Springs, MS 39566-7000
Relatively little information is available on the feeding habits of the Florida pompano (Trachinotus carolinus) from the eastern Gulf of Mexico. From June to October 2000, juvenile pompano were collected from coastal habitats in Mississippi, Alabama, and Florida. These shallow water habitats offer a diverse array of potential prey items for this commercially important fish. We compared feeding habits of Florida pompano based on their size and collection site. The digestive tracts of the pompano were examined, and were found to contain at least 45 different prey taxa. Crustaceans, primarily juvenile mole crabs (Emerita sp.), were the dominant food item of the juvenile pompano from all of the collection sites. Our data indicates that during the summer/fall months, juvenile pompano are opportunistic feeders utilizing the most readily available food resources of the habitats in which they forage. In addition, we found that the diversity of the pompano diet decreases as the fish grows.
1:15 EFFECT OF SALINITY ON FOOD CONSUMPTION BY THE MYSIDS, AMEPICAMYSIS BAHIA AND BOWMANIELLA FLORIDANA
Natasha R. [Magee.sup.*], Eric J. Fisher, and Paulinus Chigbu, Jackson State University, Jackson, MS 39217
Mysids serve important trophic role in aquatic ecosystems where they occur. They are omnivorous, feeding on detritus and plankton, and serve as prey for many economically important fish species. In the nearshore areas of the Mississippi Sound, at least, three species have been reported including Bowmaniella floridana, Americamysis bahia, and A. almyra. These species are euryhaline, hence are capable of tolerating considerable variations in salinity that often occur in the nearshore areas of the Sound. The objective of our study was to determine if salinity has any influence on food consumption by B. floridana and A. bahia. Mysids were acclimated in the laboratory to various salinity levels: 5, 15, and 35 ppt over a period of one week. During this period, they were fed Artemia nauplii daily. Thereafter, the mysids were transferred into 3 L plastic containers each containing a mysid. There were five replicates of each salinity treatment for a total of fifteen containers for each experiment. Mysids were then st arved for 24 hours after which they were fed sixty (60) Artemia nauplii. After six (6) hours, the nauplii remaining in each container was counted. The mysids were subsequently killed, measured and identified. Food consumption by B. floridana was highest at 5 ppt and least at 35 ppt (P = 0.0001). No significant differences were observed among salinity treatments in the number of nauplii ingested by A. bahia (P = 0.096). It seems, therefore, that salinity is an important factor influencing growth and life history of B. floridana.
1:30 MULTIPLE PATERNITY IN THE GRASS SHRIMP PALAEMONETES PUGIO
Michelle A. [Baragona.sup.*], Lisa A. Haig-Ladewig, and Shiao Y. Wang, University of Southern Mississippi, Hattiesburg, MS 39406
Microsatellite markers were used to study the mating system of Palaemonetes pugio. Grass shrimp genomic libraries were screened for clones containing more than five tandem trinucleotide repeats or more than seven tandem dinucleotide repeats. Among the 11 microsatellite loci characterized, two were selected on the basis of polymorphism and ease of amplification to genotype 30 embryos from each of 10 brooding females collected from an estuary in the northern Gulf of Mexico. Results indicate that 8 of the 10 females were brooding embryos sired by more than one male.
1:45 COASTAL WETLANDS "BROWN-OUTS": ARE THEY OCCURRING IN MISSISSIPPI MARSHES?
Kristal E. [Cromer.sup.*], Matthew L. Treadway, Cynthia A. Moncreiff, John D. Caldwell, Brett R. Blackburn, and Nicole M. Opel, Cooperative Intern Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553 and Gulf Coast Research Laboratory, Sciences, University of Southern Mississippi, Ocean Springs, MS 39566-7000
Unexpected large areas of dead and dying Spartina alterniflora Loisel. were observed in Louisiana saltwater marshes during the summer of 2000. To date no causes for these "brown-outs" have been identified, although it is suspected that lack of rainfall is the reason why the plants are dying. Mississippi has experienced the same drought conditions, so there was interest in determining if this phenomenon was occurring in Mississippi's saltwater marshes. Overflights of the marshes in coastal Mississippi were conducted to look for dead and dying Spartina alterniflora. Local marshes were visited where observations on the condition of saltwater marsh vegetation were made along with measurements of surface-water and soil-water salinity. Preliminary investigations suggest this phenomenon is not occurring in coastal Mississippi.
2:15 FISHERY IMPLICATIONS OF PHYLLORHIZA PUNCTATA BLOOMS IN MISSISSIPPI COASTAL WATERS
Kirsten M. [Larsen.sup.*], Harriet M. Perry, Christine Trigg, and Tom VanDevender, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39564
Phyllorhiza punctata von Lendenfeld 1884, a scyphomedusa native to the Indo-Pacific, and introduced to the tropical Atlantic and Caribbean in the 1960s, was initially sighted in Mississippi coastal waters in mid-June, 2000. Heaviest concentrations were noted offshore and in the vicinity of barrier island passes. By mid-August, massive numbers ([sim]2 per [m.sup.2]) were present in western Mississippi Sound. The scyphomedusae are thought to have been transported from the Caribbean into the Gulf of Mexico via the Loop Current. Satellite altimetry assimilated into a numerical model from May 2000 indicates that a large eddy detached from the Loop current and moved onto the shelf in the northern Gulf. Current effects on area fisheries include clogging of shrimp nets with resultant gear damage and a decrease in trawling effort in areas where jellyfish are most numerous. Since P. punctata is a voracious filter feeder, potential impacts include a decrease in zooplankton biomass as a result of their high and constant filtering capacity. Many of Mississippi's fishery resources have planktonic larvae and there is concern that larval numbers may be reduced and overall abundance of these species affected. Peak abundance of meroplankton was coincident with bloom conditions of P. punctata. Long-term ecological effects of this non-indigenous species are unknown.
2:30 MISSISSIPPI SOUND'S PHYTOPLANKTON POPULATIONS: WERE THEY AFFECTED BY THE APPEARANCE OF PHYLLORHIZA PUNCTATA?
Matthew L. [Treadway.sup.*], Kristal E. Cromer, Cynthia A. Moncreiff, John D. Caldwell, Brett R. Blackburn, and Nicole M. Opel, Cooperative Intern Program, Mississippi Gulf Coast Community College-Jackson County Campus, Gautier, MS 39553 and Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs MS 39566-7000
Phyllorhiza punctata were discovered in the Mississippi Sound in May of 2000 by researchers at the Dauphin Island Sea Lab and the USM Institute of Marine Sciences. This exotic jellyfish feeds by filtering large volumes of water, stripping it of phytoplankton, zooplankton, and small fish and crustaceans. Because of this it competed with native fauna and may have altered the structure of food webs in Mississippi Sound. To examine the possible effects of Phyllorhiza punctata on phytoplankton, which form the base of the food web, we looked at chlorophyll a, total suspended solids, and phytoplankton community structure. These variables should allow any major impacts from jellyfish invasion to be detected. Since Phyllorhiza punctata has changed into a different life cycle stage, we may not know the full potential of their effects until they reappear in the spring time.
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|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2001|
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