Introduction

 

The department aims to obtain a mechanistic understanding of the structure and dynamical behaviour of marine macrobenthos populations, ranging from the shelf margin to the intertidal. The general approach that is followed and which is also one of the great challenges in modern ecology, is to try to understand the properties of populations and communities on the basis of characteristics of individual organisms. The department focuses both on the role of bottom-up (food input and competition for food and other resources) and top-down (predation) processes in structuring benthic communities.

 

Research methods include

(1) field observations, along with long-term (and wide range) surveys;

(2) manipulative field experiments, e.g. using new lander technology;

(3) laboratory experiments, e.g. using the experimental large-scale tidal facilities; and

(4) modelling.

 

Within the department research focuses intensively on the tidal flats in the Wadden Sea and some tropical systems, notably in north-west Australia and West Africa and on the soft-sediments of the North Sea and continental shelf margin. The tidal flats of the Wadden Sea, easily accessed from the institute, have the advantage that they are relatively species-poor and, in terms of biomass, dominated by only a few species. This means that the problem of complexity, which is a major obstacle in linking community behaviour to individual characteristics, may be less severe. In the western Wadden Sea, only four species (three bivalves and one polychaete) account for 80% of the total biomass of the intertidal infauna. Detailed studies focus on these four most abundant species, and their predators. Recent developments in the employment of landers that can be installed at the seafloor for longer periods, enables advanced manipulative experiments. Hence, the experimental approach, so far only possible on the tidal flats, can now also be followed in our second area of interest, the shallow parts of the North Sea.

 

In addition to detailed individual-oriented studies, long-term population and community studies are being performed in all three types of systems. In the Wadden Sea twice-annual surveys started in the late 1960s. These long-term studies focus on the population dynamics of the benthic fauna and their predators, the food conditions for the benthic fauna, and on environmental conditions, such as water temperature. They provide an important mean for generating and validating hypotheses on the structuring processes in marine ecosystems. Mollusc shells accommodate an archive for studying environmental and climatic changes over much longer periods.

 

Most of our studies are embedded in national or European programmes. Although emphasis is put on benthic communities, studies on seabirds and marine mammals are also performed, yet mainly externally (national government, EU) funded.