Meagan Gonneea, Marine Chemistry & Geochemistry


Coral-based proxies of tropical hydrology: method development, validation and application

Coral-based proxies of tropical hydrology: method development, validation and applicationSubmarine groundwater discharge is the flow of water from land to the sea, but unlike rivers, this flow occurs underground. Largely unstudied until the advent of radioisotopes as groundwater tracers around fifteen years ago, this component of the hydrologic cycle is proving to be volumetrically as important as river flow (although a mixture of fresh and seawater). Given the nature of groundwater, with a high sediment to water ratio and the fact that the water accumulates its chemical signature over the entire recharge area, the total chemical load discharging to the coast can be quite large. Groundwater is in fact the most important source of nutrients, trace metals and pollutants to some coastal regions. While submarine groundwater discharge has been studied for nearly twenty years, it is not an easy phenomenon to quantify, given its diffuse and heterogeneous nature. Thus, while we are beginning to appreciate the spatial variability groundwater discharge displays, we have a very limited understanding of temporal variability on the scale of months, to years and beyond. Yet knowledge of this type of variability is necessary to understand how groundwater discharge will respond to climate change, and thus how coastal systems sensitive to groundwater discharge will react to climate shifts. What is required to fill this knowledge gap is a high-resolution historical record of submarine groundwater discharge.