Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2018-02-27T16:54:04Z No. of bitstreams: 1 Dissertação Rodrigo Wanick final .pdf: 4229460 bytes, checksum: 57308d047672489aade74b41da93624d (MD5) / Made available in DSpace on 2018-02-27T16:54:04Z (GMT). No. of bitstreams: 1 Dissertação Rodrigo Wanick final .pdf: 4229460 bytes, checksum: 57308d047672489aade74b41da93624d (MD5) / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / Neste trabalho foi realizado a identificação das metalotioneínas na ostra Crassostrea rhizhophore para sua aplicação em estudos de caratér ambiental. Para realizar a identificação, forma necessárias adaptações no metódo de extração protéica descrito por Viarengo et. al (1997). / In this work metallothioneins were identified in the mangrove oyster Crassostrea rhizophorae to be used in environmental studies, employing modifications in the protein extraction method descrived by Viarengo et. al (1997).

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-11-01T12:22:04Z No. of bitstreams: 1 Izabel Cristina da Silva Almeida Funo.pdf: 3957187 bytes, checksum: 43e9590f401b0f3753de80740bfee8f0 (MD5) / Made available in DSpace on 2017-11-01T12:22:04Z (GMT). No. of bitstreams: 1 Izabel Cristina da Silva Almeida Funo.pdf: 3957187 bytes, checksum: 43e9590f401b0f3753de80740bfee8f0 (MD5) Previous issue date: 2016-02-19 / This thesis evaluated productive and biological parameters of the native oyster on Maranhão Island to contribute to the improvement of cultivation methods suitable to the region’s environmental characteristics. To attain this objective, three experiments were conducted which evaluated the efficiency of capturing oyster spats in artificial collectors (experiment II); the growth and the survival of the oyster Crassostrea gasar, exposed to different salinity levels (experiment I) and submitted to different cultivation systems (experiment III). The most important results in this study demonstrate that the C. gasar species is resistant to a wide range of salinity, and can be cultivated in marine regions with salinity from 30-35, and in estuaries in which the salinity is not equal to or lower than 5. It was found that the spat capture of the oysters was significantly influenced by the type of collector, location and period of collection (P<0.05, MANOVA). The spat collection was significantly higher in the PVC collector and at point II (mangue) (P<0.05, Tukey). The spat capture took place during the whole year, and the dry period (with less rainfall and higher salinity) was more propitious to spat collection, while the rainy period (with lower salinity) had higher growth of the individuals. The growth of the C. gasar oysters was significantly higher in the longline cultivation system (P<0.05, Student t test). Nevertheless, no significant difference was found in survival between the cultivation systems tested (P>0.05 Student t test). The months with greater rainfall, concentration of particulate inorganic matter, food availability (particulate organic material and chlorophyl a) and with lower salinity and temperature had better oyster growth. On the other hand, there was a greater agglomeration of organisms undesirable to cultivation at this time, which were associated to the lower survival rate registered in this period. / A presente tese visou avaliar parâmetros produtivos e biológicos da ostra nativa na ilha do Maranhão, a fim de contribuir com o aprimoramento de metodologias de cultivo adequadas às características ambientais da região. Para atingir esse objetivo, foram desenvolvidos três experimentos, os quais avaliaram a eficácia da captação de semente de ostras em coletores artificiais (experimento II); o crescimento e a sobrevivência da ostra Crassostrea gasar, exposta a diferentes níveis de salinidades (experimento I) e submetida a diferentes sistemas de cultivo (experimento III). Os resultados mais relevantes neste estudo demonstram que a espécie C. gasar é resistente a uma ampla faixa de salinidade, podendo ser cultivada em áreas marinhas com salinidades entre 30 e 35, como também em áreas estuarinas nas quais a salinidade da água não apresente valores iguais ou inferiores a 5. Verificou-se que a captação de sementes de ostras foi influenciada significativamente pelo tipo de coletor, local e período de coleta (P<0,05, MANOVA). A coleta de sementes foi significativamente superior no coletor de PVC e no ponto II (mangue) (P<0,05, Tukey). A captação de semente ocorreu durante todo ano, sendo que o período seco (menor intensidade pluviométrica e maior salinidade) mostrou-se mais propício para a coleta de semente, enquanto no período chuvoso (menor salinidade) foi registrado maior crescimento desses indivíduos. O crescimento das ostras C. gasar foi significativamente superior no sistema de cultivo espinhel (P<0,05, teste t de Student). Contudo, não foi constatada diferença significativa da sobrevivência entre os sistemas de cultivo balsa e espinhel (P>0,05, teste t de Student). Os meses com maior intensidade pluviométrica, concentração de material particulado inorgânico, disponibilidade de alimento (material particulado orgânico e clorofila a) e com menor salinidade e temperatura favoreceram o crescimento das ostras. Por outro lado, resultaram em maior aglomeração de organismos indesejáveis ao cultivo, os quais foram associados à menor sobrevivência registrada nesse período.

Oyster reefs provide valuable ecosystemservices that contribute to coastal resilience. Unfortunately, many reefs have been degraded or removed completely, and there are increased efforts to restore oysters in many coastal areas. In particular, much attention has recently been given to the restoration of shellfish reefs along eroding shorelines to reduce erosion. Such fringing reef approaches, however, often lack empirical data to identify locations where reefs are most effective in reducing marsh erosion, or fully take into account habitat suitability. Using monitoring data from 5 separate fringing reef projects across coastal Louisiana, we quantify shoreline exposure (fetch + wind direction + wind speed) and reef impacts on shoreline retreat. Our results indicate that fringing oyster reefs have a higher impact on shoreline retreat at higher exposure shorelines. At higher exposures, fringing reefs reduced marsh edge erosion an average of 1.0 m y-1. Using these data, we identify ranges of shoreline exposure values where oyster reefs are most effective at reducing marsh edge erosion and apply this knowledge to a case study within one Louisiana estuary. In Breton Sound estuary, we calculate shoreline exposure at 500 random points and then overlay a habitat suitability index for oysters. This method and the resulting visualization show areas most likely to support sustainable oyster populations as well as significantly reduce shoreline erosion. Our results demonstrate how site selection criteria, which include shoreline exposure and habitat suitability, are critical to ensuring greater positive impacts and longevity of oyster reef restoration projects.

No description available.

Widely regarded as a keystone species and ecosystem engineer, the eastern oyster Crassostrea virginica plays a vital role in estuarine environments. Complex, three-dimensional oyster reefs act as havens for biodiversity and contribute to ecological processes. Recently, concern for this resource has arisen in Mosquito Lagoon, Florida, the southernmost limit along the Atlantic coast for undisturbed, intertidal reefs of C. virginica. Since the 1990s, intense recreational boating activity has caused atypical dead margins (mounds of disarticulated shells) to emerge on the seaward edges of oyster reefs located along major navigational channels. Once dead margins are formed, little is known about their influence on biotic composition and interactions on oyster reefs. This study focused on the affect of dead margins on: (1) mobile species biodiversity and distribution, (2) reef architecture, and (3) the affect of structural variables on predation of juvenile oysters. To determine if dead margins influenced the biodiversity of mobile species on oyster reefs, lift nets (1 m2) were deployed within Mosquito Lagoon for one year (June 2004 - June 2005). These nets (5/site) were deployed on the back-reef areas of six reefs (3 reference reefs and 3 reefs containing dead margins). To simulate reef habitat, one and a half liters of live oysters were placed within each net. Lift nets were checked monthly and surveyed for all mobile species. The resulting data were assimilated into a species inventory containing 65 species of fishes, mollusks, crustaceans, worms, and echinoderms. The two most abundant species present on reefs in Mosquito Lagoon were the big-claw snapping shrimp Alpheus heterochaelis, a filter-feeder, and the flat-back mud crab Eurypanopeus herbstii, a predator of oyster spat. Contrary to expections, analyses of community metrics showed that dead margins did not significantly affect the biodiversity of back-reef areas on oyster reefs. Modified lift nets (0.25 m2) were placed on six different oyster reefs (3 reference reefs and 3 containing dead margins) to test if dead margins affected the distribution of mobile species inhabiting oyster reefs. Nine nets were arranged to cover three separate areas of each reef: the fore-reef (3 nets), mid-reef (3 nets), and back-reef (3 nets). Half a liter of oyster shells were placed inside each net. These nets were checked weekly, for five weeks and species richness, density, and biomass were recorded. Analyses revealed that all community metrics were significantly higher on reference reefs than reefs affected with dead margins. Further, a significant drop in all three metrics was seen on the mid-reef area of affected reefs. The absence of species on this area is hypothesized to be due to a lack of water, shade, and habitat complexity. To document architectural differences, two types of transects were run along five reference reefs and five reefs with dead margins. First, quadrat transects determined the percent of live oysters, the percent of shell clusters, topographic complexity (using chain links), and the angle of shells on each reef type. Transect lines were stretched parallel to the water line and covered all three reef areas (fore-reef, mid-reef, and back-reef). The results showed reference reefs to have approximately four-fold more live oysters, approximately twice as many shell clusters, and significantly greater topographic complexity. Numbers of live oysters and shell clusters were greater on the fore-reef and back-reef areas of both reef types. Second, laser transects were used to record reef profiles and the slope of fore-reef areas. Transect lines were stretched perpendicular to the water line and every 20 cm the distance between the lagoon bottom and reef top was measured. Vertical reef profiles and fore-reef slopes were significantly different between reference reefs and reefs with dead margins. Dead margins compressed reef widths, increased center peaks, and increased slopes on the fore-reef area by two-fold. Lastly, field experiments were conducted to determine the affect of dead margins on the vulnerability of oyster spat to predation. Structural variables (e.g. shell orientation, single versus shell clusters, reef slope) were manipulated and effects on oyster mortality were observed. Three predators were tested: the blue crab Callinectes sapidus, the common mud crab Panopeus herbstii, and the Atlantic oyster drill Urosalpinx cinerea. Structural variables did not have a significant influence on oyster mortality; however, a significant difference was established between predators. Panopeus herbstii consumed the most juvenile oysters, followed by U. cinerea and then C. sapidus. Together, these findings document ecological implications of dead margins on C. virginica reefs and reinforce the urgent need for enhanced regulations and restoration. If the intensity of recreational boating remains unregulated, dead margins will continue to increase. Thus, in order to maintain the diversity and productivity of Mosquito Lagoon, it is crucial to fully understand how dead margins alter the biogenic habitat and biotic communities of oyster reefs.

Sea level rise and changing storm frequency and intensity resulting from climate change create tremendous amounts of uncertainty for coastal species. Intertidal species may be especially affected since they are dependent on daily inundation and exposure. The eastern oyster Crassostrea virginica is an economically and biologically important sessile intertidal species ranging from Canada to the Gulf of Mexico. Declines and changes in distribution of oyster populations has forced commercial harvesting to spread from subtidal to intertidal reefs. We investigated the potential responses of intertidal C. virginica to sea level rise, and the response of larval settlement to sedimentation which is likely to increase with higher water levels and storm frequency. Inundation was used as a proxy for sea level rise. We hypothesized four possible outcomes for intertidal oyster reefs as a result of changes in inundation due to sea level rise: (a) intertidal reefs become subtidal and remain in place, (b) intertidal reefs will be lost, (c) intertidal reefs migrate shoreward upslope and remain intertidal, and (d) intertidal reefs will grow in elevation and remain intertidal. To test the plausibility of these four outcomes, oyster ladders were placed at two sites within Apalachicola Bay, Florida, USA. Ladders supported oyster recruitment mats at five heights within the range of intertidal elevations. The bottom-most mat was placed near mean low tide, and the top mat near mean high tide to investigate the effect of tidal inundation time on C. virginica. Sediment traps were attached to ladders with openings at equal elevation to the oyster mats. Ladders were deployed for one year starting in June 2012, and again in June 2013, during peak oyster recruitment season. Monthly for six months during year one, sediment was collected from traps, dried to constant weight and weighed to obtain a monthly average for total sediment at each elevation. At the end of one year, oyster mats were collected from the field and examined for the following responses: live oyster density, mean oyster shell length of live oysters, mean oyster shell angle of growth relative to the benthos, and mean number of sessile competitors. We used AICc to identify the most plausible models using elevation, site, and year as independent variables. Oyster density peaked at intermediate inundation at both sites (maximum 1740 oysters per m2), it decreased slightly at the mean low tide, and sharply at the mean high tide. This response varied between years and sites. Mean oyster shell length peaked near mean low tide (6.7 cm), and decreased with increasing elevation. It varied between years and sites. Oyster shell angle of growth relative to the benthos showed a quadratic response for elevation; site but not year affected this response. Sessile competitor density also showed a quadratic response for elevation and varied between sites and years. Barnacles were the primary spatial competitor reaching densities of up to 28,328 barnacles per m2. Total monthly sedimentation peaked at the lowest elevations, and varied by site, with an order of magnitude difference between sites. Sediment increased with decreasing elevation. Outcomes a, c, and d were found to be viable results of sea level rise, ruling out complete loss of intertidal reefs. Outcome (a) would be associated with decrease in oyster density and increase in oyster length. Outcome (c) would require the laying of oyster cultch upslope and shoreward of current intertidal reefs, as well as the removal of any hard armoring or development. Outcome (d) remained possible, but is the least likely requiring a balance between sedimentation, oyster angle of growth, and recruitment. This should be further investigated. A laboratory experiment was designed to test relative impact of varying sediment grain sizes on settlement of C. virginica larvae. Previous studies showed that suspended solids resulted in decreased larval settlement when using mixed sediment grain sizes. Predicted storm levels and hurricane levels of total suspended solids were used in flow tanks. Sediment from the field experiment was sieved into seven size classes, the most common five of which were used in the experiment since they represented 98.8% of total mass. Flow tanks were designed and built that held 12 aged oyster shells, instant ocean saltwater, and sediment. Oyster larvae were added to the flow tanks and allowed one hour to settle on shells. Each run utilized one of the five size classes of sediment at either a high or low concentration. Following the one-hour settlement period, oyster shells were removed from the flow tank and settled larvae were counted under a dissecting microscope. Settlement was standardized by settlement area using Image J. AICc model selection was performed and the selected model included only grain size, but not concentration. A Tukey's post hoc test differentiated < 63 µm from 500 – 2000 µm, with the < 63 µm grain size having a negative effect on oyster larval settlement. This indicates that the smaller grain sizes of suspended solids are more detrimental to oyster larval settlement than larger grain sizes. The oyster ladder experiment will help resource managers predict and plan for oyster reef migration by cultch laying, and or associated changes in oyster density and shell length if shoreward reef growth is not allowed to occur. The laboratory experiment will help to predict the impacts of future storms on oyster larval recruitment. Together this information can help managers conserve as much remaining oyster habitat as possible by predicting future impacts of climate change on oysters.

Endocrine disrupting chemicals (EDCs) are compounds that can interfere with hormone signaling pathways and are now recognized as pervasive in estuarine and marine waters. One prevalent EDC in California’s coastal waters is the xenoestrogen 4-nonylphenol (4-NP), which has been shown to impair reproduction, development, growth, and in some cases immune function of marine invertebrates. To further investigate effects of 4-NP on marine invertebrate immune function we measured total hemocyte counts (THC), relative transcript abundance of immune-relevant genes, and lysozyme activity in Pacific oysters (Crassostrea gigas) following bacterial infection. To quantify these effects we exposed oysters to dissolved phase 4-NP at high (100 μg l-1), low (2 μg l-1), or control (100 μl ethanol) concentrations for 7 days, and then experimentally infected (via injection into the adductor muscle) the oysters with the marine bacterium Vibrio campbellii. 4-NP significantly altered the effects of bacterial infection had on THC. Oysters exposed to both high and low 4-NP did not experience a bacteria-induced increase in THC, as seen in control oysters. We also determined that V. campbellii infection induced differential expression of a subset of immune-related genes tested (Cg-bigdef2, Cg-bpi1, Cg-lys1, Cg-timp) in some, but not all, tissues; 4-NP exposure altered expression patterns in two of these genes (Cg-bpi1 and Cg-tgase). Exposure to 4-NP alone also caused differential expression in some genes (Cg-bpi1, Cg-galectin1, Cg-clec2). Lastly, low levels of 4-NP significantly increased lysozyme activity 24 h post-infection. These results suggest that exposure to 4-NP can alter both cellular and humoral immune responses to bacterial infection in C. gigas.

Foodborne disease outbreaks associated with the protozoan parasite Cryptosporidium spp. are an emerging public health concern. Shellfish, including Eastern oysters (Crassostrea virginica) in Chesapeake Bay and other Atlantic coastal waters, have been identified as a potential source of Cryptosporidium parvum infection for humans. The inactivation of C. parvum and other pathogens in raw molluscan shellfish would provide increased food safety for normal and at-risk consumers. The objectives of this study were to evaluate the efficacy of three alternative food-processing treatments (e-beam irradiation, microwave energy, and high hydrostatic pressure processing) on the viability of C. parvum oocysts in Eastern oysters. Oysters were artificially infected with the Beltsville strain of C. parvum and subjected to the three treatments in separate experiments. The effects of the treatments were evaluated by inoculation of the processed oyster tissues using the neonatal mouse bioassay. E-beam radiation of in-shell and shucked oysters treated with doses of 1.0, 1.5 or 2.0 kGy produced significant reductions (P < 0.05) in C. parvum mouse infectivity. A dose of 2.0 kGy completely terminated the infectivity of C. parvum and did not adversely affect the visual appearance of the oysters. Microwave treatments of shucked oysters at time (temperature) exposures of 1 sec (43.2°C), 2 sec (54.0°C), and 3 sec (62.5°C) produced a reduction in C. parvum mouse infectivity of 26.7%, 33.3%, and 46.7%, respectively. Microwave treatments at 2 sec (54.0°C) and 3 sec (62.5°C) showed extensive changes in oyster meat texture and color. Thus due to lack of efficacy and unacceptable tissue changes, microwave treatment of oysters is not considered a viable food processing method. High pressure processing of shucked oysters at all pressures tested (305 MPa, 370 MPa, 400 MPa, 480 MPa, 550 MPa) significantly (P < 0.05) reduced infectivity of C. parvum oocysts as measured by the neonatal mouse bioassay. A treatment of 550 MPa at 180 sec produced the maximum decrease of C. parvum infectivity (93.3%). The results indicate that HPP (high pressure processing) can produce significant (P < 0.05) reductions in infectivity of C. parvum oocysts. Measurement of tristimulus color values of pressurized raw oysters at extended processing times from 120 sec to 360 sec at 550 MPa showed an increase (P < 0.05) in whiteness. One (e-beam irradiation) of the three food-processing treatments shows promise for commercial applications to reduce public health risks from cryptosporidiosis in Eastern oysters. / Ph. D.

The objective of this research was to determine if Vibrio populations, specifically V. vulnificus were affected in oysters by the processing methods employed in Virginia. This study was conducted between July and September in 1995 and during the month of August of 1996 when water temperature was expected to be high. Oysters were harvested from Virginia and the Gulf coast and shucked and blown by Virginia processors. They were tested for aerobic plate counts incubated at 35-37°C, salt content, pH, total Vibrios and V. vulnificus populations before and after processing. Oysters were stored in crushed ice and maintained an internal temperature of 1°C and tested at 5, 10, and 15 days after processing. Oysters were also stored at -9°C tested every one to two weeks. Procedures described in the Food and Drug Administration’s Bacteriological Analytical Manual for identification of V. vulnificus were followed. V. vulnificus populations were not significantly affected by blowing. V. vulnificus populations decreased in oysters stored at 1°C and -9°C. V. vulnificus levels decreased faster in blown oysters harvested from the Gulf coast. Vibrio populations were not significantly reduced by blowing in oysters that were 1°C. Oysters stored at -9°C showed decreased Vibrio populations. pH and APC showed an inverse relationship in oysters that were 1°C. In oysters stored at -9°C, pH and APC showed a positive correlation. Significance of these correlations varied. / Master of Science

Live eastern oyster (Crassostrea virginica) reefs have declined by 62.6% in Mosquito Lagoon (ML) along the eastern Florida coast since 1943. While this species creates reefs by successive generations of oysters recruiting to conspecific shells, C. virginica can also attach to non-reef substrates including mangrove roots and armoring (e.g., seawalls), which may help counteract reef habitat loss. In recent decades, warmer winters have enabled red (Rhizophora mangle) and black (Avicennia germinans) mangrove expansion in subtropical salt marshes and temperate estuaries where oyster reefs occur. Additionally, 11.8% of ML's shorelines have been armored as of 2018. These non-reef substrates add potential surface area and a 3-D substrate for oyster settlement. Aerial imagery from 1984 to 2021 was used to track extent (ha) changes in mangroves, oyster reefs, and hard armoring. Mangrove extent increased 859.2%, hard-armoring extent decreased 56.3%, and live oyster reef area decreased 55.3% (rate: -0.86 ha/yr). Additionally, 83 oyster reefs were 100% converted into mangrove islands, resulting in a 654.6% increase in the number of new conversions between 1984 and 2021. To determine if oyster abundances on non-reef substrates are comparable to live oyster reefs, oyster characteristics were compared between substrate types using field surveys to collect metrics (live densities, shell heights, canopy heights). Mean densities and canopy heights (± S.E.) were highest on concrete/metal seawalls (481.8 ± 113.0 oysters m2 and 678.4 ± 408.6 mm, respectively). Mean shell heights (± S.E.) were largest on oyster reefs (52.0 ± 2.2 mm) and within black mangrove pneumatophores on oyster reefs (41.3 ± 10.0 mm). Between 1984 and 2021, oyster reefs lost 291.0 oysters/ha versus non-reef habitats, which added an average (± S.E.) of 104.7 ± 78.2 oysters/ha. These findings suggest mangrove roots and armoring support oyster reef-level populations by providing 3-D attachment space and partially offset oyster losses on reefs.