2009 Volume 21 Issue 4 Pages 97-111
ABSTRACT: The impact of mussels (Mytilus galloprovincialis), attached to quaywalls in Amagasaki port, on deposition of materials was studied in situ using sediment traps. Observed lowering concentration of dissolved oxygen and phytoplankton near the walls was attributed to metabolic activity of the mussels. Due to deposition of feces and pseudofeces discharged by filter-feeders, sedimentation rate were doubled under the mussels attached on the quaywall comparing to an adjacent reference site. Even more obvious impact was increase in particle organic carbon (POC) and particle nitrogen (PN) fluxes, which are tripled comparing to those at referent site leading to local organic enrichment near the walls. Increased deposition changed downward fluxes of all investigated metals (Zn, Cu, Pb, Cd and Cr). Results of factor analysis indicated influence of mussels on the redistribution of metals and their concentration in deposited matter, first of all, on redistribution and concentration of Zn and Cd through the selection of fine particles. However, contrary to organic matter, whose concentration in surface sediments and trapped material reflect a clear gradient, which decreases from the wall to the referent position, metal concentrations do not reveal similar effect.
