IN PLACE

The IN PLACE -Integrated Network for Production and Loss Assessment in the Coastal Environment- team examines the limitations and possibilities of an integrated monitoring network to study primary productivity of pelagic and benthic microalgae, including an automated FRRF on a fixed monitoring platform.

The problem of undersamling phytoplankton

Many of monitoring programs of pelagic microalgae in the Wadden Sea have a sampling frequency of once to twice per month at maximum. In spite of the importance to primary production, the dynamics of benthic microalgae are not measured at all. This leads to 'under sampling' of phytoplankton during the growing season, causing changes in the patterns of algal dynamics to remain unnoticed and changes in the functioning of the food unexplained. Because high-frequency measurements can be carried out with automated equipment, it is possible to estimate growth conditions (light, temperature, salinity, turbidity) and  biomass of micro algae. The automated measurement of primary production is, however, a lot more complex. 

Optimal techniques

At present, optical techniques are available that measure the photosynthetic activity of phytoplankton, including the promising FRR (Fast Repetition Rate) fluorometer. To know how well a local field observation represents a larger area, such measurements should be performed at various locations. This can be done by manual and continuous measurements from automated sampling platforms and combining research vessels with Earth Observation (EO) data from aircraft and satellites. 

The resulting information on the spatial temporal variation in primary production by microalgae in the World Heritage Wadden Sea might contribute to a better understanding of the role of microalgal dynamics in the food web, and thus the carrying capacity of these intertidal mudflat ecosystems.