Thesis: Monosulfidic Black Ooze in the Peel Harvey Estuary System – formation, oxidation and transformation to pyrite in a eutrophic estuary receiving acid sulfate soil drainage.
Monosulfidic Black Ooze (MBO) forms as a natural part of the global sulfur cycle and when undisturbed is recognised as playing an important role in improving water quality. However they are regarded as a potential environmental hazard as they release contaminant stores and deoxygenate water when oxidised. In estuarine systems influenced by eutrophication and acidic drainage, MBO formation can be accelerated. Anomalously high concentrations of MBO have been found in the Peel Harvey estuary system (as well as some other eutrophic systems). My research will investigate the spatial distribution of total reactive sulfur in the Peel Harvey sediments, and the interactions with nutrients and metals. It will also involve the potential mechanisms for retarding the transformation of MBO to pyrite (resulting in higher MBO accumulation), and how the oxidation of the MBOs impact water quality of the system.
Why my research is important
Eutrophication of estuarine systems is an internationally recognised problem in terms of ecological and economic sustainability of coastal communities. It is becoming increasingly accepted that sulfur geochemistry plays an important role in affecting (both beneficially and adversely) estuarine sediment and water quality.
MBOs can be a significant environmental hazard, and understanding sulfur biogeochemistry during their formation and oxidation is critical to effectively manage MBOs. This is particularly true when such systems are subject to disturbance by development and recreation, such as is seen in the Peel Harvey estuary system. My research will have applications in improving the environmental health of estuary systems during MBO disturbance. It will also strengthen understanding of the mechanisms controlling accumulation of anomalously high MBO in some eutrophic estuary systems (increased formation and decreased transformation to pyrite).