Quantifying the benthic metabolism of tropical coral reefs and seagrasses in a changing climate

• Main Author: Mallon, Jennifer
• Format: Thesis
• Language: English
• Published: 2023
• Subjects: GC Oceanography; GE Environmental Sciences; Ocean acidification
• Online Access: http://theses.gla.ac.uk/83381/; https://theses.gla.ac.uk/83381/3/2022MallonPhD.pdf

Tropical coastal regions are home to around a third of the world’s population, where entire communities depend upon ecosystem services derived from an interconnected network of coral reefs, seagrasses, mangroves, and associated fauna. The tropical coastal zone incorporates numerous unique and widely distributed habitats, from mangroves to mud flats, however this thesis focusses on two interconnected marine tropical ecosystems. Coral reefs and seagrasses are global biodiversity hotspots with high rates of productivity which fuel coastal biogeochemical cycling. Seagrasses support blue carbon sequestration, sediment retention, and provide critical habitat. Biogenic calcification by coral reef organisms constructs massive calcium carbonate (CaCO3)structures, as calcifying organisms deposit skeletons over thousands of years. This robust CaCO3 structure protects coastlines from storms by absorbing the impact of wave energy and is critical for maintaining healthy shores. Coral skeletons form a uniquely intricate architecture which provides habitat for diverse ecological communities and many economically important species. However, anthropogenic climate change threatens the ecological function of these systems. High concentrations of carbon dioxide (CO2) are absorbed into the oceans, resulting in ocean acidification and warming waters, with catastrophic impacts on calcifying organisms. As the global climate crisis threatens coastal ecosystems and the services they provide, the development of metrics to track and predict changes to ecosystem function are essential for advancing scientific conservation efforts. Biogeochemical measurements of benthic metabolism are proposed as an efficient tool for long-term and high-resolution tracking of changes to species composition and ecosystem function. Benthic metabolism in coastal ecosystems describes carbon cycling driven by biological processes: inorganic (calcification – dissolution) and organic carbon metabolism (photosynthesis – respiration). These processes can be measured ...