Seagrass Cymodocea nodosa as a trace element biomonitor: Bioaccumulation patterns and biomonitoring uses

• Roots and leaves of C. nodosa show similar bioaccumulation capacity.
• Rhizomes of C. nodosa act as transit organs of trace elements.
• C. nodosa adopts exclusion strategies only for some toxic elements.
• Roots and leaves of C. nodosa act as bioindicators of trace elements in sediments.

This study aimed to investigate the bioaccumulation patterns of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the seagrass Cymodocea nodosa. Results showed that roots and leaves of C. nodosa tend to accumulate similar values of trace elements but significantly greater than rhizomes, which seem to act as transit organs. Cu was the only element with similar concentrations in the three organs. C. nodosa showed no correlation with trace elements in water, whereas Cd, Cu, Ni and Zn in sediments were correlated with C. nodosa. This study showed also that C. nodosa tends to adopt an exclusion strategy for some toxic elements like Cr except As. In general, the roots and leaves of C. nodosa acted as bioindicators of several trace elements in sediments. Leaves are easier to sample and are suggested for short-term monitoring, given their periodic turnover. In turn, roots are more suitable for collecting historical information on past environmental conditions.