Effects of Chemical Inducers on Larval Oyster Settlement in Suboptimal Conditions

Corresponding author (Biological Science): Alexz Carpenter, [email protected]://egrove.olemiss.edu/pharm_annual_posters_2022/1005/thumbnail.jp

Effect of Ploidy on Early Oyster Life Stage Tolerance of Salinity and Temperature

Corresponding author (BioMolecular Sciences): Christian Boudreaux, [email protected]://egrove.olemiss.edu/pharm_annual_posters_2022/1003/thumbnail.jp

Negative impacts of flood-associated water quality stressors on early oyster life stages

Presenter: Jessica Pruetthttps://egrove.olemiss.edu/pharm_annual_posters_2021/1008/thumbnail.jp

Transmission studies and the composition of prokaryotic communities associated with healthy and diseased Aplysina cauliformis sponges suggest that Aplysina Red Band Syndrome is a prokaryotic polymicrobial disease

Aplysina cauliformis, the Caribbean purple rope sponge, is commonly affected by Aplysina Red Band Syndrome (ARBS). This transmissible disease manifests as circular lesions with red margins and results in bare spongin fibers. Leptolyngbya spp. appear to be responsible for the characteristic red coloration but transmission studies with a sponge-derived isolate failed to establish disease, leaving the etiology of ARBS unknown. To investigate the cause of ARBS, contact transmission experiments were performed between healthy and diseased sponges separated by filters with varying pore sizes. Transmission occurred when sponges were separated by filters with pore sizes ≥ 2.5 μm, suggesting a prokaryotic pathogen(s) but not completely eliminating eukaryotic pathogen(s). Using 16S rRNA gene sequencing methods, 38 prokaryotic taxa were significantly enriched in diseased sponges, including Leptolyngbya, whereas seven taxa were only found in some, but not all, of the ARBS-affected sponges. These results do not implicate a single taxon, but rather a suite of taxa that changed in relative abundance with disease, suggesting a polymicrobial etiology as well as dysbiosis. As a better understanding of dysbiosis is gained, changes in the composition of associated prokaryotic communities may have increasing importance for evaluating and maintaining the health of individuals and imperiled coral reef ecosystems

Effect of ploidy on salinity and temperature tolerance in early life stages of the Eastern oyster (\u3ci\u3eCrassostrea virginica\u3c/i\u3e)

The U.S. Gulf of Mexico contains the largest remaining wild oyster fishery in the world, but populations have declined in recent decades. A growing interest in off-bottom aquaculture that relies on triploid eastern oysters (Crassostrea virginica) has emerged in the Gulf region, yet these faster growing oysters suffer high mortality as adults during low salinity (\u3c5) events in warmer summer months. The combined effects of low salinity and high temperature stress on early life stages of triploid oysters are unknown. Early life stages are particularly crucial to understand because triploid oysters do not occur naturally and must be reared in hatchery settings, requiring appropriate water conditions to yield the greatest survival and growth. Thus, we tested the effects of different temperatures (28 ºC and 32 ºC) and salinities (5, 10, and 15) on diploid and triploid oysters at three critical production stages: veliger, pediveliger, and spat. Veliger survival was significantly lower for triploids relative to diploid oysters at all experimental conditions, but triploid veligers had faster growth than diploids at 32 ºC and salinity of 15. Pediveliger settlement was not affected by ploidy type and was reduced only at high temperature (32 ºC) and the lowest salinity (5). Diploid spat showed highest survival at 28 ºC and 15 salinity, while triploids survived best at 32 ºC and 15 salinity. Triploid spat attained greater shell height compared to diploids in our 6- day exposures, but growth decreased for both ploidies at lower salinities. At the salinity and temperature levels examined, diploid early life stages performed best at 28 ºC and 15 salinity, whereas triploids were more successful at 32 ºC and 15 salinity. A broader understanding of the combined effects of environmental stressors will improve the success of hatchery production yields and the resulting economic and environmental benefits of the oyster industry

Microbiome diversity and metabolic capacity determines the trophic ecology of the holobiont in Caribbean sponges

Sponges are increasingly recognized as an ecologically important taxon on coral reefs, representing significant biomass and biodiversity where sponges have replaced scleractinian corals. Most sponge species can be divided into two symbiotic states based on symbiont community structure and abundance (i.e., the microbiome), and are characterized as high microbial abundance (HMA) or low microbial abundance (LMA) sponges. Across the Caribbean, sponge species of the HMA or LMA symbiotic states differ in metabolic capacity, as well as their trophic ecology. A metagenetic analysis of symbiont 16 S rRNA and metagenomes showed that HMA sponge microbiomes are more functionally diverse than LMA microbiomes, offer greater metabolic functional capacity and redundancy, and encode for the biosynthesis of secondary metabolites. Stable isotope analyses showed that HMA and LMA sponges primarily consume dissolved organic matter (DOM) derived from external autotrophic sources, or live particulate organic matter (POM) in the form of bacterioplankton, respectively, resulting in a low degree of resource competition between these symbiont states. As many coral reefs have undergone phase shifts from coral- to macroalgal-dominated reefs, the role of DOM, and the potential for future declines in POM due to decreased picoplankton productivity, may result in an increased abundance of chemically defended HMA sponges on tropical coral reefs

Coral recruitment is impacted by the presence of a sponge community

© 2019 Peng Luo et al., published by De Gruyter, Berlin/Boston. C23H13NO4, monoclinic, P21/n (no. 14), a = 11.6537(6) Å, b = 5.1315(2) Å, c = 26.8047(13) Å, β = 96.266(3)°, V = 1593.4(13) Å3, Z = 4, Rgt(F) = 0.0531, wRref(F2) = 0.1432, T = 90.0(5) K

Combined and Independent Effects On Hypoxia and Tributylin On mRNA Expression and Physiology of the Eastern Oyster (\u3ci\u3eCrassostrea virginica\u3c/i\u3e)

Oyster reefs are vital to estuarine health, but they experience multiple stressors and globally declining populations. This study examined effects of hypoxia and tributyltin (TBT) on adult Eastern oysters (Crassostrea virginica) exposed either in the laboratory or the field following a natural hypoxic event. In the laboratory, oysters were exposed to either hypoxia followed by a recovery period, or to hypoxia combined with TBT. mRNA expression of HIF1-α and Tβ-4 along with hemocyte counts, biomarkers of hypoxic stress and immune health, respectively, were measured. In field-deployed oysters, HIF1-α and Tβ-4 expression increased, while no effect on hemocytes was observed. In contrast, after 6 and 8 days of laboratory-based hypoxia exposure, both Tβ-4 expression and hemocyte counts declined. After 8 days of exposure to hypoxia + TBT, oysters substantially up-regulated HIF1-α and down-regulated Tβ-4, although hemocyte counts were unaffected. Results suggest that hypoxic exposure induces immunosuppression which could increase vulnerability to pathogens

Combined and independent effects of hypoxia and tributyltin on mRNA expression and physiology of the Eastern oyster (Crassostrea virginica)

© 2020, The Author(s). Oyster reefs are vital to estuarine health, but they experience multiple stressors and globally declining populations. This study examined effects of hypoxia and tributyltin (TBT) on adult Eastern oysters (Crassostrea virginica) exposed either in the laboratory or the field following a natural hypoxic event. In the laboratory, oysters were exposed to either hypoxia followed by a recovery period, or to hypoxia combined with TBT. mRNA expression of HIF1-α and Tβ-4 along with hemocyte counts, biomarkers of hypoxic stress and immune health, respectively, were measured. In field-deployed oysters, HIF1-α and Tβ-4 expression increased, while no effect on hemocytes was observed. In contrast, after 6 and 8 days of laboratory-based hypoxia exposure, both Tβ-4 expression and hemocyte counts declined. After 8 days of exposure to hypoxia + TBT, oysters substantially up-regulated HIF1-α and down-regulated Tβ-4, although hemocyte counts were unaffected. Results suggest that hypoxic exposure induces immunosuppression which could increase vulnerability to pathogens

Energetics of a Predator-Prey Interaction: Corals and Coral-feeding Fishes

Various hypotheses have been proposed to account for defense of a feeding territory by coral-feeding fishes. However, before the adaptive significance of feeding territories can be fully understood, energetics of the predator/prey relationship must be quantified. Energetics of the interaction between the coral Pocillopora meandrina and the territorial coral-feeding damselfish Plectroglyphidodonjohnstonianus were examined to determine the minimum energetic requirement of the predator and the effect of predation on productivity of the prey. Coral productivity for colonies exposed (experimental) and not exposed (control) to predation, and metabolic rates of the fish were determined. Fish required 240 cal /day, while corals produced 0.2 1 cal/cm2/day. A typical colony of P. meandrina did not produce enough energy to sustain a fish. Data presented here indicate that territories of two or more colonies should provide sufficient energy. Predation by an individual P. johnstonianus did not have a measurable effect on coral primary productivity