Already from the beginning of my scientific career, research on marine environments have been the lead focus in my biological and ecological studies. My PhD on marine ecological communities is mainly focussed on explaining shifts in population dynamics in all trophic levels in both the present and the past. Not only by analyzing shifts in marine populations, determine physiological requirements in different life stages of important marine species (lower- and higher trophic levels) is important in order to predict how sea food webs will chance due to (a)biotic factors in the Wadden Sea. Combining the analysis of historical data, the collection of field work data and the inventory of potential important nursery habitats in the Wadden Sea will tell us more about how marine populations on larger world wide scale might change in the future.