Unraveling the complexity of subtropical seagrass nitrogen cycling : a stable isotope approach

Seagrass ecosystems are important and complex habitats recognised as hotspots of coastal nitrogen cycling, however the underlying processes are not well constrained. This thesis explores nitrogen input and loss processes within individual seagrass meadows via novel applications of stable isotopic techniques. By comparing above and below ground processes it was revealed that leaves and their associated epiphytes were the main drivers of nitrogen fixation and that morphologically diverse seagrass species favour different nitrogen loss processes. Overall this research unravels some of the biogeochemical complexity that controls whether a seagrass community acts as either a nitrogen source or sink.