groundwater-flow

Increasing human pressure and climate change are predicted to alter coastal ecological processes, but at present we have no capacity to understand or predict these impacts. Making such predictions and managing complex ecosystems requires a mechanistic understanding of groundwater flow and nutrient dynamics.

Submarine groundwater discharge (SGD) has become increasingly recognized as a major pathway for the flow of nutrients, organic carbon, metals, and even contaminants from land into the coastal ocean. While there have been a number of studies that focus on the role of SGD in estuarine and coastal biogeochemistry, only a few of these studies have occurred in the southern hemisphere, and none in southern Africa. Such information is critical for understanding not only regional SGD and its influence on the local environment, but our understanding of how SGD impacts global ocean biogeochemistry. Through the use of radium isotope methods, we are investigating groundwater flow and nutrient fluxes between iSimangaliso Wetland Park and the coastal ocean. Understanding the mechanisms of nutrient delivery and the composition of those nutrients is essential for elucidating how these estuarine and coastal ecosystems develop in response to local (direct increases in human population), regional (upstream development), and large scale climate change. The project dovetails with the international GEOTRACES program (http://www.geotraces.org).