Posidonia oceanica mat is considered a long-term bioindicator of contamination. Storage and sequestration of trace elements (TEs) and organic carbon (Corg) were assessed in dead P. oceanica mat and bare sediments from a highly polluted coastal marine area (Augusta Bay, Central Mediterranean). Sediment elemental composition and sources of organic matter have been altered since the 1950 s. Dead P. oceanica mat displayed a greater ability to bury and store TEs and Corg than nearby bare sediments, acting as a long-term contaminant sink over the past 120 years. Here, TEs, being probably associated with the mineral fraction, were stabilised and trapped despite die-off of the overlying P. oceanica meadow. Mat deposits registered historic contamination phases well, confirming their role as natural archives for recording TE trends in marine coastal environments. This sediment typology is enriched with seagrass-derived refractory organic matter, which acts mainly as a diluent of TEs. Bare sediments showed evidence of inwash of contaminated sediments via reworking, more rapid and irregular sediment accumulation, and due to the high proportions of labile organic matter a greater capacity to store TEs. Through different processes, both sediment typologies represent a repository for chemicals and may pose a risk to the marine ecosystem as a secondary source of contaminants in the case of sediment dredging or erosion.
Authors: Di Leonardo R, Mazzola A, Cundy AB, Tramati CD, Vizzini S. ;Full Source: Environmental Toxicology & Chemistry. 2016 Jun 27. doi: 10.1002/etc.3539. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][Epub ahead of print] ;[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]