To determine how biogeochemical fluxes and trophic structure in coastal ecosystems are related to the nature and strength of physical forcing functions, and to evaluate the importance of biological macrostructures in modifying the physical mixing processes in the benthic boundary layer.
Estuaries and coastal seas are among the most productive ecosystems in the biosphere. The underlying mechanisms for the high production are poorly understood, but the interactions between the benthic and pelagic environment in these shallow systems are likely to be important. Coupling in shallow waters between the mainly autotrophic pelagic zone and the mainly heterotrophic benthos varies on a continuum in time, from hours to months, depending on the intensity of vertical mixing and establishment of stratification. Several gaps in our understanding of important biogeochemical processes have been filled in recent years, however, the importance of physical forcing and high frequency variability on biogeochemical processes in shallow coastal waters hitherto have been almost completely ignored, primarily due to lack of technology. Recent improvements in instrumentation, however, now allow us to measure spatial and temporal variation in turbulent kinetic energy dissipation rate directly, even close to the water column boundaries. In the project, the main focus will be on physical and biogeochemical interactions on the vertical scale in the coastal zone.
The project will use a combination of laboratory and field studies. A key element in the project is campaign periods carried out in 3 European coastal waters of contrasting energy input - the macrotidal eutrophic Oosterschelde estuary, Holland, the microtidal eutrophic Isefjord, Denmark, and the microtidal oligotrophic Jomqueet Bay, Spain. The campaigns will consist of a core program with contemporaneous measurements of physical mixing processes and biogeochemical fluxes and a number of process studies related to specific tasks within the project. The specific process studies can be divided into 4 main areas: physical mixing, bentho-pelagic coupling, benthic boundary layer and benthic canopies. Laboratory studies will include development of methods to be used in the field and various types of flume and mesocosm studies. In the field emphasis will be on measurements of vertical profiles just above the bottom or within and above plant canopies and will be related to turbulent intensity.
The individual tasks and campaign periods will result in a set of biogeochemical process models, that will be integrated into a physical transport/turbulence framework to result in a coupled physical-biogeochemical model for the coastal zone.This model will be an important tool in distinguishing between ecosystem changes caused by natural events and human activities.
Funding SchemeCSC - Cost-sharing contracts
21020 Ispra - Varese
452 96 Stroemstad
2500 EX Den Haag ('S-gravenhage)
4401 EA Yerseke