A large fraction of the material transferred across the land-ocean boundary is intercepted by coastal sediment beds and associated benthic communities. In particular, sandy sediments act as dynamic, natural biogeochemical reactors intercepting elemental transfers from continents to the ocean.
This way, permeable beds located at the borderline between coastal plains and productive marine ecosystems may be the intersecting point of pelagic borne inputs of organic matter and receptors of major concentrations of inorganic compounds, including key pollutants, seeping from the underlying strata.
This makes them the perfect locus to study for example, the influence of carbon loading on denitrification of groundwater-borne nitrogen, among other reaction pathways linking biogeochemical cycling to human activity in the coastal zone.
All evidence gathered so far shows that here, it is the dynamics of advective flow that controls, to a large extent, microbial diversity and the rates of microbial processes, the size of organic and inorganic pools and even their changes within a very large range of timescales.
The mediatory role of coastal sediments over anthropogenic N fluxes to the coastal zone is far from certain, and generally unknown for SGD, but its comprehension is a crucial aspect of future environmental management.
Research within this theme is organized around 5 main questions:
- What is the main biogeochemical framework underpinning the role of sandy sediment beds as bio-catalytic filters?
- How important are sandy permeable sediments located on the borderline between inland groundwater inputs and productive marine ecosystems as sources or sinks of nutrients?
- How do site-specific attributes including interfacial flow rates and associated material fluxes, act as drivers of biogeochemical reactivity of permeable sediments and how does it in turn affect local marine ecosystem health?
- How and to what extent different benthic transformation pathways affecting specific solute species inter-relate and contribute to the functional role and service provided by coastal ecosystems?
- How can a deeper conceptual and mechanistic understanding of the role of natural sediment beds as bio-catalytic filters contribute to the development of ecosystem mitigation and restoration strategies?