Browsing by Author "Bonaventura, Celia"

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    Acute Toxicity and Sub-Lethal Effects of Non-Point Source Pollutants on Invertebrates
    (2007-05-07T19:07:30Z) Romano, Jocelyn Ann
    Non-point source pollution is not generated from any single source, rather can arise from a mixture of agricultural, residential, and industrial activities. As a result of these activities millions of tons of chemicals enter into aquatic environments annually with the potential to disrupt the fragile ecosystems existing within. Common anthropogenic compounds most frequently seen in estuarine environments include pesticides, antifoulants, polycyclic aromatic hydrocarbons (PAH), and industrial solvents. This dissertation examines the acute toxicity and sub-lethal effects of diuron, CuPT, B(a)P, and styrene in the mud snail, Ilyanassa obsoleta, the American oyster, Crassostrea virginica, the sea urchin, Lytechinus variegatus, and/or the barnacle, Amphibalanus (= Balanus) amphitrite. In addition, the general effects of non-point source pollution within the Rachel Carson Estuarine Research Reserve (RCERR) were examined at six sites in order to gain a better understanding of the current health of this unique habitat. Of the four compounds tested, only the industrial solvent, styrene, resulted in an LC50 (1341 µg L-1, I. obsoleta) that was within the range of currently reported environmental levels. Diuron and CuPT did not elicit mortality at environmentally relevant concentrations, but did significantly reduce fecundity in I. obsoleta and C. virginica and fertilization success and larval development in L. variegatus. The only notable sub-lethal effect elicited by the PAH, benzo(a)pyrene, was a significant decrease in egg capsule production by I. obsoleta following exposure to concentrations as low as 50 µg L-1. Within the RCERR, animals from Sites 4, 5, and 6 were observed to have significant differences with respect to fecundity, condition index, and/or ECOD activity when compared to conspecific organisms from control Site 1. This is most likely a consequence of their proximity to anthropogenic sources. Large variation in mortality (15-98.9%) was observed when families of A. amphitrite from a single population where exposed to CuPT. It is often difficult to extrapolate data from laboratory findings into natural populations. Frequently the organisms used under laboratory conditions are genetically very similar, while field population can vary with anthropogenic exposure. Caution must be taken when developing protocols for risk assessment to ensure that actual environmental conditions are being represented.
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    Polycyclic Aromatic Hydrocarbons and the North Atlantic Right Whale
    (2011-04-29) Pelc, Carey
    The critically endangered North Atlantic right whale (Eubalaena glacialis) is a protected species and yet it continues to exhibit high mortality and low reproductive rates. A large amount of known mortality to right whales is caused by ship strikes and gear entanglements. Protective policies have reduced the likelihood of these types of mortalities, but low reproductive rates continue to be of concern. Many cumulative factors can play a role in the poor reproductive success of right whales, but little is known on what role contaminants such as polycyclic aromatic hydrocarbons (PAH) play. This masters project aimed to explore the relationships between PAH concentrations in right whale tissue and prey, and Cytochrome P450 (CYP1A) expression relative to various life parameters such as location, gender, age, and reproductive variables. Dermal biopsy samples were obtained from both North Atlantic and Southern right whale species in various years between 1993-2000. CYP1A expression in the endothelial tissues of the biopsies was measured. Polycyclic aromatic hydrocarbon concentrations were measured in biopsy samples from the North Atlantic species as well as from their zooplankton prey in various nearshore and offshore habitats. The results of this study show that there are significant differences in CYP1A expression in whale samples from different feeding and calving areas. Differences in the levels of expression are likely attributed to levels of contaminant exposure through prey consumption. A cross-sectional comparison of CYP1A expression and PAH levels in biopsy samples did not show a significant correlation to reproductive parameters, but a firm conclusion regarding a causal relationship was not possible due to paucity of data. A more longitudinal study is suggested to obtain higher quality information about the relationship between PAH levels and CYP1A expression and reproductive parameters. Understanding the relationships between contaminant levels and reproductive success can be useful to inform managers of other variables that could be impacting right whale health and the recovery of the species.
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    United States Small Cetacean Rehabilitation Policy: Driving forces behind a socially motivated policy
    (2004) Gluch, Nora
    Within the Untied States the policy reflects the importance society as a whole places on an issue. Cetaceans hold a special status in American society as a cultural icon due to their intelligence, social interaction, and extensive ability to communicate. Cetacean rehabilitation policy exemplifies the construction of a socially driven policy. The rehabilitation of cetaceans is a high cost endeavor with a low success rate, but is still a formal component of marine mammal protection. The structure of the stranding and rehabilitation network illustrates the socially motivated nature of rehabilitation policy. In an examination of major newspapers over the last five years in the U.S., three major themes driving the development of cetacean rehabilitation policy emerge. Responsibility/moral obligation, emotional connection between humans and cetaceans, and anthropomorphizing of cetaceans all play an essential role in the construction of cetacean rehabilitation policy. Understanding the social function that cetacean rehabilitation policy plays within U.S. society is crucial to tailoring it in order to adequately meet the needs of the public and society. It is essential to describe and legitimize rehabilitation policy for its inherent worth within the social and political framework of the United States.