关键词:
n-Alkanes
Posidonia oceanica
Carbon and nitrogen stable isotopes
Mediterranean Sea
Aegean Sea
Alexandroupolis Gulf
摘要:
We analyzed n-alkane contents and their stable carbon isotope composition, as well as the carbon and nitrogen isotope composition (delta C-13, delta N-15) of sediment organic matter and different tissues of Posidonia oceanica seagrass sampled in Alexandroupolis Gulf (A.G.), north-eastern Greece, during 2007-2011. n-Alkane contents in P. oceanica and in sediments showed similar temporal trends, but relative to bulk organic carbon content, n-alkanes were much more enriched in sediments compared to seagrass tissue. Individual n-alkanes in sediments had similar values than seagrass roots and rhizomes and were more depleted in C-13 compared to seagrass leaves and sheaths, with delta C-13 values ranging from -35 parts per thousand, to -28 parts per thousand and from -25 parts per thousand, to -20 parts per thousand, respectively. n-Alkane indexes such as the Carbon Preference Index, carbon number maximum, and n-alkane proxy 1 (C-23 + C-25/C-23 + C-25 + C-29 + C-31) indicate strong inputs of terrestrial organic matter, while the presence of unresolved complex mixtures suggests potential oil pollution in some sampled areas. (C) 2015 Elsevier Ltd. All rights reserved.