STATISTICAL EVALUATION OF ECOSYSTEM PROPERTIES INFLUENCING THE UPTAKEOF AS, CD, CO, CU, HG, MN, NI, PB AND ZN IN SEAWEED (FUCUS-VESICULOSUS) AND COMMON MUSSEL (MYTILUS-EDULIS)

In order to evaluate the influence of geographically varying marine ec osystem properties on the uptake of trace elements in bioindicators, s amples were taken of seaweed (Fucus vesiculosus) and common mussel (My tilus edulis) along the North Sea and Baltic Sea coast. Seasonal varia tions of the bioindicator status were minimized by sampling within 1 m onth. Ecosystem properties considered were the geographical position, the salinity and the concentrations of the macroelements Ca, Fe, K, Mg , Na, P and S in the bioindicators. Trace elements studied were As, Cd , Co, Cu, Hg, Mn, Ni, Pb and Zn. Factor analysis of the concentration patterns in the bioindicators and of salinity as a function of locatio n confirmed the influence of the geographically varying salinity on th e biological uptake of macroelements and trace elements. This influenc e of salinity was higher in the case of seaweed than in the case of mu ssel. Comparison of the geographical courses of the macroelement and t race-element concentrations by cluster analysis revealed corresponding courses for As and Hg in both bioindicators. All other elements showe d different courses in seaweed and mussel. Subsequent cluster analysis comparing locations with respect to the macroelement or trace-element concentration patterns in the bioindicators, indicated a clear separa tion of North and Baltic Sea locations. However, the trace-element con centration patterns provided a regionally less distinctive ecosystem a rrangement than those of the macroelement ones. The results of the clu ster analysis were verified by discriminant analysis forming groups of locations with respect to geographical position and salinity. Results of discriminant analysis demonstrated, both for seaweed and for musse l as bioindicators, that the location groups formed according to the m acroelement concentration patterns corresponded well with the geograph ical regions in the order of salinity. On the other hand, location gro ups based on the trace-element concentration patterns again showed a m odified less distinctive ecosystem arrangement than the location group s based on macroelement concentration patterns. This confirms modified conditions for the uptake of trace elements in seaweed or mussel in c omparison to the uptake of macroelements. (C) 1997 Elsevier Science B. V.