Biogeochemistry of the MAximum TURbidity Zone of Estuaries (MATURE): some conclusions

In this paper, we give a short overview of the activities and main results of the MAximum TURbidity Zone of Estuaries (MATURE) project. Three estuarie s (Elbe, Schelde and Gironde) have been sampled intensively during a joint 1-week campaign in both 1993 and 1994. We introduce the publicly available database, and compare trends and patterns in suspended matter, nutrients an d organic matter in the three estuaries. Despite the large differences in s uspended particulate matter concentrations between the estuaries, some gene ral relationships can be deduced. Organic matter dynamics is shown to be de termined by sorption onto the particulate matter. This in turn induces a pr edictable change in bacterial degradability. Floc size, determined by an in situ camera, is a function of organic content, suspended matter concentrat ion and (in a highly non-linear way) salinity. Higher trophic levels in the biological system are negatively affected by the dilution of their food wi th indigestible particles. (C) 1999 Elsevier Science B.V. All rights reserv ed.