Arsenic metabolism in marine organisms

  • Tuti Siregar

Student thesis: Doctoral Thesis

Abstract

Arsenic has been categorised as a toxic element and potentially hazardous to marine organisms and human health. Arsenic is naturally found in seawater and sediment, although in low concentrations. In its 5th oxidation state, called arsenate (AsV), bioavailability is high due to its similarity with the common marine nutrient, phosphate. Although arsenic is famous for its highly toxic effects and has been called a ‘king of poison’, not all arsenic species are dangerous. Arsenic toxicity is strongly dependent on chemical speciation. There are many studies on the concentration of total arsenic and arsenic species in marine organisms, but it remains unclear what the end-product of arsenic cycling in the marine environment is. The proposed pathways related to the formation of arsenobetaine (AB) in marine animals are also still poorly understood. The aim of this thesis was to provide new insights into arsenic metabolism and transmission from primary producers (macroalgae) to primary consumers (sea urchins and herbivorous fish)...

Despite a large body of research on arsenic metabolism in marine organisms, there remains large gaps in knowledge about arsenic transformation in marine food chains and consequent risks to human health. This thesis has shown that inorganic arsenic found in the marine environment is readily taken up by marine primary producers due to its resemblance to the essential nutrient, phosphate, and then is transmitted through marine food chains. However there are a series of complex transformations a detoxification processes which take place within macroalgae and grazers. While it was possible to partially describe this process, there is a need for further work utilising high-resolution mass spectrometry to describe the actual pathway of the biotransformation process of AsV into PO4 As-sugars. There is also a need for longer term studies of uptake across marine food chains and interactions with a wider range of other stressors.
Date of Award2022
Original languageEnglish
SupervisorRoss Thompson (Supervisor), Simon Foster (Supervisor) & Jill Bartlett (Supervisor)

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