Land-Ocean Interactions in the Coastal Zone
Coastal systems are biogeochemical hotspots located at the intersection of material and energy transfer between continents, oceans and the atmosphere. The coastal ecotone is thus a transport-reaction node, one that modulates elemental fluxes between continental and marine ecosystems.
Observable effects of this functional role include higher rates of primary production in coastal waters promoted by higher nutrient availability, on the one hand introduced by surface and subterranean discharge and benthic remineralisation, and, on the other hand, by upwelling water masses which deliver remineralised inorganic solutes produced by the breakdown of organic compounds settled in the continental slope and deep sea.
As an example, the Nitrogen (N) cycle is globally perturbed by artificial N fixation and subsequent input of "new" bio available N into terrestrial and marine ecosystems - this perturbation is set to grow.
Coastal waters are a common receptor of excess N derived from human activities. Their generally high primary production can be enhanced to the point of eutrophication or even dystrophy, leading to degraded water and environmental quality, increased organic matter content, heterotrophy and massive ecological change.
Thus, predictions of the behaviour of bio available elements, coupled with accurate estimates of their transformation pathways, reaction rates and fluxes, at the continental-marine boundary are of vital importance in the context of an Ecosystem-based Approach (EBA) to Marine and Coastal management.
Research within this theme is organized around 5 main questions:
- What role does Submarine Groundwater Discharge (SGD), primarily amongst others, play as a vector for the transport and transformation of land-derived solutes into marine systems and what are its main forcing agents?
- How does nutrient (N, P, Si) enrichment interact with other stressors (human influence in hydrology, exploitation of ecosystem services, toxic contaminants, climate) to drive changes in the functional role of marine systems?
- How do system-specific attributes modulate the response of marine systems to contamination and nutrient enrichment?
- How does anthropogenic environmental change in the coastal zone impact marine environmental health and modify the Earth system as a host for humanity and other species?
- Do environmental managers need to take into account specific processes occurring at this interface while implementing water and land-use policies in the littoral zone, and if so, how?