Compartmentation of trace metals in Cymodocea nodosa from a heavily polluted area (Central Gulf of Gabes; Southern Mediterranean Sea): Potential use of the seagrass as environmental monitoring and bioremediation tool

Abstract

This study was conducted to better understand the adaptative strategies of Cymodocea nodosa occurring in the heavily polluted environment of central Gulf of Gabes (SE Tunisia). Cd, Cu, Pb and Zn concentrations were assessed in the seagrass roots, rhizomes, and leaves, and in the surrounding seawater and sediments. Sediments were found to be the main source of contaminants bioaccumulated in C. nodosa. Bioaccumulation patterns differed significantly with metals and plant organs. While Cd, Cu and Zn were found to accumulate in leaves, Pb concentrates mainly in roots. In the heavily polluted environment of the Gulf of Gabes, C. nodosa seems to have developed two different adaptative strategies: metal trapping in roots and metal transfer from permanent (roots) to temporary (leaves) organs. These mechanisms allow the seagrass to remove the excess of metals. These properties show the potential use of C. nodosa not only as bioindicator but also as an effective bioremediation tool.