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Abstracts of Oral Presentations

CHARACTERIZATION OF GROWTH ANOMALIES INPORITES COMPRESSA USING METABOLOMICS AND TRACE ELEMENTAL ANALYSIS

Andersson, E (GPMB, The University of Charleston, SC), Stewart, J (NIST), Work, T (US Geological Survey), Woodley, C (NOAA), Anderson, P (College of Charleston), Schock, T (NIST) and Day, R (NIST)

Coral growth anomalies (GAs) are tumor-like coral lesions, generally characterized by localized increased skeletal growth resulting in an abnormal protuberant mass on a coral colony. There are competing hypotheses of causative factors, including pathogens, UV radiation, and water quality stressors. Although GAs have been characterized in multiple coral species using field surveys and laboratory techniques, the mechanisms responsible for the disruption of the skeletal morphology and associated impacts to coral soft tissues remain unknown. The current study utilizes a combination of 1H NMR metabolomics and ICP-MS trace element analysis to further characterize these anomalies.

Paired fragments comprising lesion (GA) and healthy Porites compressa were collected (n=15) from Coconut Island (Oahu, Hawaii) where prevalence of GAs is high. Significant increases were detected in skeletal V/Ca, Mo/Ca, Sb/Ca, U/Ca, and Sr/Ca ratios, as well as a significant decrease in the skeletal Mg/Ca ratio, in GA samples relative to healthy samples (paired sample T­‐test; FDR adjusted p­‐value <0.05). Potential geochemical and physiological implications of the trace elemental differences between GA and healthy samples will be discussed. Metabolomics data analyses revealed 89 peaks important for discriminating between GA and healthy metabolic signatures. Metabolite identification and possible physiological implications of these metabolites will be discussed. Evaluating the metabolome of the disease state in conjunction with complementary ICP-mass spectrometry trace element data on the skeletal anomalies will provide novel and diverse insight into the biochemistry associated with the disease.


TEMPORAL CHANGES IN SOUTH ATLANTIC OCEAN FISH BIODIVERSITY

Baker, N (GPMB, The University of Charleston, SC), McGlinn, D (College of Charleston), Ballenger, J (SCDNR), Plante, C (College of Charleston) and Strand, A (College of Charleston)

Due to pressures from anthropological activities and environmental changes, large decreases in the number of species have been reported across the globe. This “global biodiversity crisis” has become a topic of much interest, with studies noting declines of species numbers and individuals and increased homogenization of communities. However, there is much ambiguity on the extent and nature of these changes, due to the fact that the scale of the sampling studies effects the observed results. This study used a scale-dependent approach to measure changes the fish community has undergone in the south Atlantic Ocean over the past three decades. Using coastal trawl data provided by the SCDNR Southeast Area Monitoring and Assessment Program - South Atlantic, we analyzed various facets of biodiversity for the historic (1990-1995) and modern (2010-2015) fish assemblages. We found that there have been no significant changes in the species richness, though the modern assemblage has a much higher number of individuals. The modern community is also patchier, and has a slightly higher spatial turnover of both rare and common species. These results provide a better understanding of the changes occurring in the south Atlantic fish community across multiple spatial scales, and demonstrate the importance of scale in the analysis when conducting studies of biodiversity.


QUANTIFYING MICROPLASTICS IN THE GUT OF STRANDED COMMON BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) FROM SOUTH CAROLINA, USA

Battaglia, FM (GPMB, The University of Charleston, SC)

Plastic pollution is one of the most common and persistent problems impacting marine ecosystems to date. An increasing number of studies focus on the potential for microplastics (< 5 mm) to negatively impact marine biota, such as by hindering nutritional uptake or as a possible route for toxin transfer. Ingestion of microplastics has been reported for a variety of lower trophic level organisms in both field and laboratory studies, including zooplankton, polychaetes, bivalves, crustaceans, and fish. Conversely, ingestion by higher trophic levels remains largely unexplored. The common bottlenose dolphin (Tursiops truncatus) is a long-lived resident and apex predator in coastal and estuarine ecosystems along the southeastern United States and as such, can be a sensitive gauge for environmental quality within its range. The aim of the present study is to provide the first measure for microplastic ingestion in T. truncatus by analyzing the gut contents of stranded dolphins recovered in South Carolina, USA. It is hypothesized that T. truncatus may be exposed to microplastics through its prey. The gastrointestinal tract of stranded dolphins is removed and the contents washed into glass containers. Intact prey items and otoliths are stored for separate prey analysis while the remaining gut contents are sieved to separate into size fractions. A 1M KOH solution is added to eliminate organic material and facilitate the visual identification of microplastics in samples. Findings from this investigation will aid future studies examining microplastics as a possible route for the transfer of toxins to marine apex predators like T. truncatus.


A SURVEY OF SERUM VANIN-1 CONCENTRATION ACROSS SPECIES OF DIVING MARINE MAMMALS AND TERRESTRIAL MAMMALS USING MASS SPECTROMETRY

Boxall, B (GPMB, The University of Charleston, SC), Neely, B (NIST), Van Dolah F (NOAA), McFee W (NOAA), Naylor, G (College of Charleston) and Janech, M. (MUSC)

A proteomic study of bottlenose dolphin serum identified and measured the highest concentration of pantetheinase (Vanin-1) for any mammal. Vanin-1 is known to catalyze the formation of the free-thiol antioxidant cysteamine, from the vitamin B5 precursor, pantetheine. Because diving marine mammals have a high antioxidant capacity in their tissues and blood to counter dive-induced oxidative stress; we hypothesized that elevated levels of Vanin-1 in diving marine mammals may represent an adaptation or response to diving. To test this hypothesis, serum Vanin-1 concentrations were measured across closely related mammalian taxonomic groups of terrestrial and marine mammals. Serum Vanin-1 concentrations were estimated by parallel reaction monitoring using species-specific stable isotopic peptide standards. In members of Carnivora, serum Vanin-1 concentrations were high (greater than 1.0 ug/mL) in sea lions (mean=9.16 ug/mL, ±1.0), but not detectable in dogs. In members belonging to Paenungulata, which includes hyraxes and manatees, Vanin-1 levels were high in manatees (mean=24.21 ug/mL, ±8.46), but not detectable in hyraxes. In members belonging to Euungulata, Vanin-1 levels were high in 9 out of 10 cetacean species surveyed (range=2.87-­106.38 ug/mL). A high Vanin-1 phenotype appears to be characteristic of nearly all other members of Euungulata, which includes hippos (15.75 ug/mL, n=1), ruminants (range=2.32-­45.60 ug/mL), and horses (mean=45.02 ug/mL, ±18.38). Interestingly, Vanin-1 was not detectable in pigs. In conclusion, a high serum Vanin-1 phenotype appears to be unique to diving marine mammals in Carnivora and Paenungulata, but not in Euungulata. In Euungulata, a high serum Vanin-1 phenotype appears to be an ancestral state that was retained in cetaceans.


ESTIMATING THE AGE AND SIZE DEPENDENCY OF SPAWNING FREQUENCY IN GAG AND SCAMP GROUPER OFF THE SOUTHEASTERN U.S. TO IMPROVE POPULATION MODELS

Gamboa Salazar, K (GPMB, The University of Charleston, S.C.), Wyanski, DM (SCDNR), Bubley, WJ (SCDNR), Klibansky, N (NOAA) and Sancho, G (College of Charleston)

The productivity of a fish stock can be measured by the relationship between reproductive output and recruitment into the stock. Spawning stock biomass (SSB), the total weight of mature females, is used to calculate reproductive output, but it assumes a consistent relationship between number of oocytes and fish weight. Increases in spawning frequency with size have been documented in marine fishes, invalidating this assumption. Parameters calculated from SSB-based assessments can therefore lead to inaccurate estimates of productivity and ineffective management regulations. To remove the assumption, assessments have begun to quantify reproductive output as total egg production (TEP). However, when information on spawning frequency variability is lacking, a constant spawning frequency is assumed for calculation of TEP. This study investigated the relationships between spawning frequency and both age and size in two reef fish species off the southeastern United States: Gag (Mycteroperca microlepis) and Scamp (Mycteroperca phenax). Archived gonad samples (n=7,177) were histologically examined for determination of reproductive phase and presence of spawning indicators. Regressions indicate that spawning frequency is parabolically related to both age (R2=0.807) and size (R2=0.842) for Gag, and to size for Scamp (R2=0.901). Further, an estimate of Gag TEP is 34.7% lower when calculated with an age-based spawning frequency than with a constant one. These analyses will be used to generate more accurate, age- and size-based models of reproductive output. Incorporating these models into TEP estimates should lead to more accurate calculations of stock productivity, thus providing better estimates of harvest rates to ensure stock sustainability.


EVERY INVASION TELLS A DIFFERENT STORY: CRYPTIC LINEAGES AND HYBRIDIZATION IN A COSMOPOLITAN MARINE INVERTEBRATE

Harper, K (GPMB, The University of Charleston, SC), Scheinberg, L (San Francisco State University), Boyer, K (San Francisco State University) and Sotka, E (College of Charleston)

Marine biological invasions are accelerating in number and impacts. To understand and manage such invasions, it is important to both accurately identify invasive species and identify their introduction sources and pathways. This effort is complicated by the rampant speciation and potential hybridization of invertebrates. As one case study, we collected 349 individuals of the estuarine amphipod Ampithoe valida from across native and introduced populations, Sanger sequenced mitochondrial COI and genotyped ~10K nuclear single-nucleotide-polymorphisms (or SNPs) using RADseq. Across the native range of A.valida, we found both mitochondrial and nuclear divergence between Pacific and northwestern Atlantic populations, indicating two subspecies or species. In contrast, three introduction events generated distinct genetic outcomes. An introduced population in Argentina has both Atlantic mitochondrial and nuclear genotypes. However, two California populations show varying levels of mito-nuclear discordance: San Francisco Bay populations have Pacific mitochondria and a mix of Atlantic-and-Pacific SNPs, while Humboldt Bay has Atlantic mitochondria and a mix of Atlantic-and-Pacific SNPs. The mito-nuclear discordance among introduced populations suggests recent hybridization of Atlantic and Pacific sources in these estuaries and possibly adaptive introgression of mitochondrial loci, nuclear loci, or both. More generally, we find that mitochondrial loci alone generate a mistaken demographic and evolutionary history that can be resolved with nuclear SNPs.


DETERMINING THE ELEVATIONAL RANGE AND INUNDATION PERIOD OF THE RIBBED MUSSEL (GEUKENSIA DEMISSA) ALONG A SALINITY GRADIENT IN SOUTH CAROLINA, U.S.A.

Julien, A (GPMB, The University of Charleston, SC), A. Tweel (SCDNR), N. Hadley (SCDNR), D. McGlinn (College of Charleston), and P. Kingsley-Smith (SCDNR)

The ribbed mussel, Geukensia demissa, is an ecosystem engineer that promotes salt marsh functioning throughout its range along the eastern coast of North America. Over the past 5 years, commercial landings of G. demissa in South Carolina have increased considerably, yet the fishery lacks species-specific regulations. While habitat characterization is commonly used as a management tool for other commercially important bivalves (e.g., the eastern oyster, Crassostrea virginica), such information for G. demissa in South Carolina is currently lacking. As part of a broader study to improve understanding of the ecological role of G. demissa in the salt marsh community, its elevational range and inundation period were characterized along a salinity gradient in Charleston, S.C. In Spring 2017, transects were established at 8 sites along the Ashley River. At each site, 6 transects consisting of 5 sampling points were established, and G. demissa presence or absence was recorded. Elevation was determined using survey-grade GNSS equipment. Temperature sensors were placed at 3 of the sites for 1 month, and inundation period was inferred from changes in the temperature profile during night-time high tides, when water and air temperatures could be distinguished. A logistic regression model was developed to determine the probability of G. demissa occurrence, which was greatest at elevations slightly below mean high water and at intermediate salinities (18 ppt). The model is relevant to managing the emerging fishery, as it may help in mapping G. demissa habitat, but has yet to be tested in systems outside of the Ashley River.


CIRRAL MORPHOLOGY, ACTIVITY, AND PARTICLE SIZE CAPTURE OF A COMMENSAL BARNACLE, CHELONIBIA TESTUDINARIA, RAISED IN CAPTIVITY

Lane, Z (GPMB, The University of Charleston, SC), DiTullio, J (College of Charleston), Fair, P (NOAA), Van Dolah, F (NOAA), and Zardus, J (The Citadel)

Using a novel rearing technique, the epibiotic barnacle Chelonibia testudinaria has been raised under laboratory conditions for the first time. An evolutionary history which specifically shaped this species for a commensal life on the shells of sea turtles and crabs had, in the past, made C. testudinaria difficult to cultivate in the lab. New methodology and mechanical innovation now provides an opportunity to investigate basic life history and behavioral traits of this species that were previously a challenge to address experimentally. This study aims to confirm via scanning electron and light microscopy that the cirral morphology of lab-raised individuals is comparable to that of wild conspecifics, as well as to characterize through video analysis how flow rate affects the feeding behavior of this species in slowly accelerating flume flow. Additionally, adult barnacles will be exposed to a spectrum of differently sized food particles during ninety minute feeding trials. Water samples will be collected at intervals from the experimental flume throughout each trial and the change in concentration of various sizes will be quantified with a Coulter Counter. By recoding shifts in particle size concentrations, a minimum food size can be established along with potential size-based feeding selectivity in this species.


OCCURRENCE, FATE, AND EFFECTS OF MICROPLASTICS IN THE CHARLESTON HARBOR ESTUARY, SOUTH CAROLINA

Leads, R (GPMB, The University of Charleston, SC) and Weinstein, J (The Citadel)

Microplastics are ubiquitous in the environment, occurring at concentrations as high as thousands of particles/m2. Charleston Harbor contains an average of 414±77 microplastic particles/m2 in intertidal sediments, with black fragments suspected to be tire wear particles (TWP) constituting >90% of the particles at some sites. The present study further characterized the abundance and distribution of microplastics in an effort to identify sources in Charleston Harbor. As rivers are a contributor of non-point and point source microplastics, three tributaries of Charleston Harbor—the Ashley, Cooper, and Wando Rivers—were surveyed. Intertidal sediment, subtidal sediment, and sea surface microlayer (SML) samples were collected from three sites (upstream, midstream, downstream) along each river and were analyzed for microplastics (63-500 µm). Microplastic abundance in intertidal sediments, subtidal sediments, and the SML did not differ significantly among upstream, midstream, or downstream sites. Microplastic abundance in intertidal sediments (p<0.0001) and the SML (p=0.003) differed significantly among rivers, with the Cooper River containing the fewest microplastics (63±13 particles/m2, 5±1 particles/L). Blue fibers and black TWP were the most abundant microplastics observed, constituting 26% and 28%, respectively, of total microplastics collected. The Cooper River contained the fewest microplastics but the greatest number of point source discharges, suggesting that non-point sources are a significant contributor of microplastics in Charleston Harbor. Data regarding the acute toxicity of TWP, including their effect on immune function, in grass shrimp (Palaemonetes pugio) will be presented. These results are the first to report the prevalence of TWP in the microplastic litter of a southeastern estuary and their potential effects on an ecologically important species.


OPTIMAL FORMATION OF ACCURATE JUVENILE ABUNDANCE INDICES IN STOCK ASSESSMENTS OF SOUTH ATLANTIC FISHERIES: A CASE STUDY

Reynolds, J (GPMB, The University of Charleston, SC) and Smart, T (SCDNR)

As growing human populations put an increasing demand on finite ocean resources, fisheries management tools rely ever more on high quality input data and a comprehensive understanding of model factors. Stock assessment modeling for South Atlantic (SA) king mackerel, Scomberomorus cavalla, uses inputs such as abundance indices, growth parameters, and fisheries landings. However, one underlying assumption in this modeling system is there are measurable connections among life stages. A juvenile abundance index developed from the SEAMAP-SA Coastal Trawl Survey (CTS) is presumed to represent ecological recruitment. Very weak correlations to other life stage proxies suggested a deficiency with the juvenile abundance index accuracy and indicated a more optimal formation of the index should be considered. Examination of CTS juvenile length frequencies support that the smallest juveniles appear in the summer and spring juveniles are from overwintering of the previous year class, in concert with previous observations of spawning season. Juvenile abundance indices developed using year class rather than year of sampling (as done for previous assessments) showed substantial differences, in particular reducing annual variation compared to the previous formulation. Temperature, season, and sampling region have also been found to have significant effects on the development of this index.


INVESTIGATION OF THE SALINITY TOLERANCE OF THE INVASIVE ISLAND APPLE SNAIL IN SOUTH CAROLINA

Underwood, EB (GPMB, The University of Charleston, SC), Darden, TL (SCDNR), Plante, CJ (College of Charleston), Fowler, AE (George Mason University), Knott, DM (Poseidon Taxonomic Services, LLC) and Kingsley-Smith, PR (SCDNR)

The Island apple snail (Pomacea maculata), native to South America, is an invasive freshwater gastropod currently established in several southeastern states, including South Carolina. Pomacea maculata is considered an invasive species due to the negative impacts of its intense grazing, high fecundity, ability to out-compete native species, and potential to serve as a host for the rat lungworm nematode parasite (Angiostrongylus cantonensis), which can cause eosinophilic meningitis in humans. Despite these impacts, knowledge of P. maculata specific to South Carolina is limited.

The primary aim of this study is to determine the salinity tolerance of P. maculata hatchlings. By determining the survival of P. maculata in varying salinities, resource managers can improve predictions of the capability for this species to invade brackish habitats in South Carolina. Ten hatchlings, obtained from egg clutches deposited by adult snails in a biosecure laboratory, were placed in each of five treatment salinities (0, 4, 8, 12, and 16 psu) replicated 16 times and mortality was assessed daily for 14 days. Kaplan-Meier survival analysis was conducted to determine median survival probabilities, while differences in mean survival were determined using Kruskal-Wallis tests with post-hoc Dunn's tests. 100% survival was observed at 0 psu, and 0% survival was observed at both 12 psu and 16 psu. Median survival probabilities at 4 psu and 8 psu were 87% and 22%, respectively. These results demonstrate the capability of this species to survive in upstream estuary habitats with salinities as high as 8 psu in South Carolina.


ORIGIN, EVOLUTION AND DEVELOPMENT OF THE CHORDATES

Swalla, Billie (Director, Friday Harbor Laboratories, University of Washington)

Hemichordates are a sister clade to echinoderms, but have a bilateral body plan, with a head and a posterior, more similar to chordates than to radial echinoderms. Hemichordates share all of the chordate characteristics of pharyngeal slits, an anterior/posterior axis specified by Hox genes, an endostyle and a hollow dorsal neural tube, except a notochord. Furthermore, there are similar genetic networks defining specific tissues and body regions. Some hemichordates, such as Ptychodera flava, have the capacity to regenerate their entire anterior and posterior segments, if cut in half. Remarkably, they regenerate their entire nervous system, proboscis, collar, heart and gill slits within two weeks. The number of shared characteristics that hemichordates share with chordates, suggests strongly that the deuterostome ancestor also was worm-like, with gill slits, a Hox gene specified A-P axis and most of the chordate characters. This evolutionary scenario suggests that “Chordate Origins” may be due to losses in the echinoderm and hemichordate clade