Nearshore estuarine and marine ecosystems-e.g., seagrass meadows, marshes, and mangrove forests-serve many important functions in coastal waters. A better understanding of these habitats, that serve ...as nurseries for marine species, and the factors that create site-specific variability in nursery quality will improve conservation and management of these areas.
Reduced water quality is a major local threat to coral reefs worldwide, and has caused severe declines in the health of coral reefs in Hawaii, especially the nearshore areas. The corals living in ...Maunalua Bay, Oahu are under continual stresses from sedimentation and toxicant laden runoff as a result of large-scale urbanization that has taken place in the last century. Despite prolonged exposure to these environmental stressors, some corals are able to thrive, suggesting selection (adaptation). My dissertation research investigated whether corals in the nearshore areas have genetically adapted to their reduced water quality environment. The first chapter analyzed the population genetic structure of P. lobata, which revealed clear genetic differentiation between the nearshore and offshore P. lobata populations in Maunalua Bay, as well as two reefs in West Maui. My second chapter investigated the phenotypic differences between the nearshore and offshore P. lobata genotypes, found in the first chapter, to determine if the observed genetic differentiation was formed by selection. The reciprocal transplant and common garden experimental results showed clear physiological and molecular response differences between the two genotypes, highlighting the stress resilient traits of the nearshore genotype and inherent differences in the metabolic state between the genotypes. The results from the first and second chapters, however, suggest this local adaptation might happen at the cost of genetic diversity. The Porites corals are a notoriously difficult genus to identify correctly, due to their highly variable skeletal architecture and unresolved phylogeny. In order to assess the intraspecific morphological and genetic variations in P. lobata, morphometrics and genomic (RAD-seq) analyses were conducted in my third chapter. The morphometric data revealed significant groupings of skeletal characters between the geographic locations, and population genomic analysis also supported the strong geographical signature. There was a significant correlation between the morphological and the genetic distances, suggesting the genetic basis for the skeletal morphology of P. lobata. Understanding the genetic basis of coral survival offers a critical insight into their adaptive ability, which is indispensable for protecting the essential reef-building corals from impending environmental and climate change.
Ecologically and commercially significant coral reef fishes were surveyed at 28 sites in the Turks and Caicos Islands during August 1999. Our results constitute the first quantitative census of these ...fishes and can serve as baseline information for subsequent studies. Their density and size generally were highest off West Caicos and lowest in Mouchoir Bank. Herbivore density overall showed no correlation with macroalgal index (a proxy for biomass) or live stony coral cover, but surgeonfish density was positively correlated with macroalgal index. Species richness of these select fishes was positively correlated with the species richness of stony corals that were greater than or equal to 10 cm in diameter. Current fishing pressures overall were low, and the reef-fish communities appeared relatively intact on the Turks and Caicos Banks. However, overfishing and destructive fishing practices have negatively impacted the reef fish communities on Mouchoir Bank.
Major constituents of the benthic reef community (stony corals, algae) were assessed in 28 reefs on the Caicos, Turks and Mouchoir Banks. Living stony coral cover ranged from 8-28%, averaging 18% ...overall. Montastraea annularis and M. faveolata of "intermediate" sizes (<100 cm) dominated all examined reefs. Live Acropora palmata and A. cervicornis were scarce. The most frequently recruiting scleractinians were Porites astreoides and Agaricia agaricites; Montastraea recruits were uncommon. Old partial-colony mortality (overall mean = 23%) was greater than recent partial-colony mortality (mean = 3%). Crustose coralline algae and turf algae were generally more abundant than macroalgae. Mouchoir Bank, with the most isolated reefs, was in relatively poor condition, which suggests that remoteness alone does not protect coral reefs.
Sulforaphane and allyl isothiocyanate, naturally occurring isothiocyanates, have been reported to inhibit adipocyte differentiation, but little is known about how they compare in terms of their ...potency and mechanism of action. In the present study, we compared the effects of sulforaphane and allyl isothiocyanate on the differentiation of 3T3-L1 preadipocytes. A mixture of insulin, dexamethasone, and 3-isobutyl-1-methylxanthine was used to establish a differentiation medium. We found that, at a concentration as low as one-tenth that of allyl isothiocyanate, sulforaphane reduced triacylglycerol levels, lipid-filled adipocyte quantity, and mRNA and protein levels of CCAAT-enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ). These results suggested that sulforaphane may be a more potent adipocyte differentiation inhibitor than allyl isothiocyanate. Our results may provide insight into possible strategies for the prevention of obesity and related conditions.
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