Loading...
Publication
Marine pollution effects on sea turtles nesting in São Tomé and Príncipe
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 5.45 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Marine ecosystems are increasingly threatened by pollution which poses significant risks to vulnerable species like sea turtles. São Tomé and Príncipe archipelago serves as a crucial nesting site for threatened green sea turtles (Chelonia mydas) and has the last significant rookery of the critically endangered hawksbill turtles (Eretmochelys imbricata) in the Eastern Atlantic. This thesis investigates metal and persistent organic pollutants (POPs) accumulated by female sea turtles from these populations and their impacts on turtles' health and reproductive success. In general, green turtles had higher overall metal levels than hawksbills, except for mercury and selenium. In green turtles, changes in gene expression related to detoxification, antioxidant defenses, reproduction, and embryonic development were observed, concomitantly with increased levels of specific metals and POPs. Moreover, genotoxic effects with strong links to metal contamination were identified, and in particular to Hg which was highly correlated with the formation of lobed nuclei in female erythrocytes of both species. Metals were also found to be associated with alterations in egg morphometry and in egg quality for both species, particularly affecting yolk fatty acids, with more pronounced effects in the phospholipid fraction. The POPs analysis in green turtles showed that contaminant transfer from females to their eggs is occurring, although with different transference rates depending on the specific congener or metabolite. POP contamination was further associated with alterations in the yolk's fatty acid profile of this species, posing complex risks to their embryonic development. Possible effects of the overall egg quality and POP levels on the hatching success of green turtles were also observed. Overall, this thesis identifies specific biomarkers that provide valuable tools for future monitoring studies and emphasizes the need for enhanced conservation strategies and further research on the effects of environmental contaminants on these endangered sea turtles.
Description
Keywords
Sea turtles Environmental Toxicology Metals POPs Marine Biology and Conservation Tartarugas marinhas Toxicologia Ambiental Metais Biologia Marinha e Conservação