Assessment of the sources of sedimentary organic matter in the Bohai Sea and the northern Yellow Sea using biomarker proxies

作者：Xing, Lei; Hou, Di; Wang, Xinchen; Li, Li; Zhao, Meixun^*

来源：Estuarine, Coastal and Shelf Science, 2016, 176: 67-75.

DOI：10.1016/j.ecss.2016.04.009

• Biomarker
• Terrestrial organic matter
• The Bohai Sea
• The northern Yellow Sea
• BIT

To evaluate the applicability of source proxies and to assess the sources of sedimentary organic matter in the Bohai Sea (BS) and the northern Yellow Sea (NYS), we analyzed total organic carbon (TOC), total nitrogen (TN), delta C-13 of TOC, n-alkanes, phytoplankton biomarkers, and glycerol dialkyl glycerol tetraethers (GDGTs) including branched GDGTs (brGDGTs) in 60 surface sediment samples covering the BS and the NYS. Spatial distribution comparison and principal component analysis indicate that with the exception of brGDGTs, terrestrial biomarkers have different spatial distribution pattern from marine biomarkers, suggesting that the sources control the distributions of these biomarkers in spite of hydrodynamic forcing. Significantly positive correlation (R-2 = 0.5) between TOC normalized brGDGTs content and TOC normalized crenarchaeol content suggested in situ production of brGDGTs in the BS and the NYS. The delta C-13 values, TMBR [terrestrial and marine biomarker ratio: (C-27 + C-29 + C-31 n-alkanes)/[(C-27 + C-29 + C-31 n-alkanes) (brassicasterol dinosterol alkenones)]] and BIT (branched isoprenoid tetratether index) proxy indicated high terrestrial organic matter (TOM) input near the Huanghe River Estuary, while TOC/TON did not reveal similar distribution pattern. Quantitative estimates of TOM using a binary model revealed much higher TOM percentage from delta C-13 (avg. 58%) and TMBR (avg. 31%) than from BIT (avg. 7.4%). Our results suggest that, owing to significant in situ production of brGDGTs, the BIT is not a good proxy for indicating soil OM contribution in marine sediments from the BS and the NYS.

• 出版日期2016-7-5
• 单位中国海洋大学