February 1st to 5th 2016
Olhão, Portugal
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Trace elements in future oceanic conditions in Seagrass ecosystem: Ecological implications and toxic effects.

Scientific Exhibition
Future Oceans
Wednesday, February 3, 2016 -
18:30 to 20:00

Mishra, A.K. 1 Santos, R. 2 Spencer, J.H. 3 Apostolaki, E. 4

1University of Algarve
2University of Algarve
3Plymouth University
4Hellenic Center for Marine Research

Ocean acidification (OA) and reduced pH, affects the speciation and availability of metals and the metal bio-geochemistry via alteration of metal uptake rates of the biota in marine ecosystem. Seagrass ecosystem production is predicted to increase in the future oceanic conditions, but in lower pH, trace elements concentration will increase, leading to metal toxicity and it can act as a stressor for the seagrass ecosystem. So in our work we try to quantify the concentration of trace elements and their toxicity levels in three natural (CO2) vents of Greece in seagrassPosidonia oceanica and Cymodocea nodosa. Trace elements (TE) Cd, As, Co, Hg, Cu, Pb, Fe, Ni, Mn and Zn, of sediments and seagrass (leaves, rhizomes and roots) of Posidonia oceanica and Cymodocea nodosa were analysed from the natural (CO2) vents of Greece by ICP-OES and ICP-MS technique. Trace Element Pollution Index (TEPI), Trace element spatial index (TESVI) provided detailed concentration and availability of trace elements in sediments. Critical toxicity level (CTL) and Bio concentration factors (BCF) provided TE concentration for seagrass, to detect the toxicity level and the difference between sediment and seagrass concentration respectively for each element. TE concentrations increased from the control towards the (CO2) vents. In the high (CO2) conditions the concentration of Fe (37625.21 mg/kg), Co (13.19 mg/kg), Pb (3.96 mg/kg) were higher in sediments, whereas Cu (248.35mg/kg), Zn (82.84mg/kg), Ni (43.00 mg/kg), As (525.30 mg/kg), Hg (0.46 mg/kg) were higher in roots, Mn (2006.59) mg/kg in rhizomes and Cd (1.74 mg/kg) in leaves. In the control sites TE was lower in concentration than the vents. Cu (248.35mg/kg), Pb (3.96 mg/kg) and Ni (43.00 mg/kg) concentration was higher than CTL to both P. oceanicaand C. nodosa. Trace elements concentration increased and varied for each (CO2) vents between sediments and seagrass significantly along the gradient with toxic effects of few TE in future ocean conditions.
keywords: 
P. oceanica, C. nodosa, CTL, TEPI, TESVI, ICP-OES, ICP-MS

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