Glycerol dialkyl glycerol tetraethers in surficial coastal and open marine sediments around China: Indicators of sea surface temperature and effects of their sources
Glycerol dialkyl glycerol tetraethers in surficial coastal and open marine sediments around China: Indicators of sea surface temperature and effects of their sources
复制标题
DOI：
10.1016/j.palaeo.2013.12.006
复制
发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Haoda Zhou;Jianfang Hu;B. Spiro;P. Peng;Jianhui Tang
中科院分区：
文献类型：
--
作者：
Haoda Zhou;Jianfang Hu;B. Spiro;P. Peng;Jianhui Tang
精确重建过去海表温度（SST）对于了解过去气候及其变化具有重要意义。近年来，基于甘油二烷基甘油四醚（GDGT）的TEX 86（由86个碳原子组成的四醚的四醚指数）已被开发成为一种很有前途的SST重建指标。本研究以我国近海和外海18°N ~ 38°N水深1000 m的表层沉积物为研究对象，研究了GDGT的分布特征< 100 or >。GDGT的分布模式反映了GDGT的生物来源和生境特征。分支GDGTs（brGDGTs）在黄海的分布与黄河下游相似，表明黄海brGDGTs来源于陆源土壤。而环化率的变化的支链四醚（CBT）衍生的pH值在珠江口（PRE）表明，brGDGT也可能在沿海沉积物或在水体中原位产生。在浅水区（水深< 100 m，黄海、东海和PRE），与年平均SST卫星相比，TEX 86 H SST（SST 86 H）被高估或低估，很可能是由季节性或冷偏地面信号的叠加造成的。在南海（SCS），在水深> 1000 m处，SST 86 H与卫星测定的年平均SST吻合较好，表明TEX 86 H温度在这些研究区域以及类似的深水环境中具有适用性。这些研究结果为分支/类异戊二烯指数（BIT）和TEX 86作为温度和古温度指标在中国近海和开阔海域的应用提供了依据。
Accurate reconstruction of past sea surface temperature (SST) is important for the understanding of past climate and its variations. Recently, the TEX86indicator (TetraEther indeX of tetraethers consisting of 86 carbon atoms), based on glycerol dialkyl glycerol tetraethers (GDGTs) has been developed into a promising proxy for SST reconstruction. In this study, we investigated the distribution of GDGTs in surficial sea bottom sediments from coastal and open marine settings around China between 18°N and 38°N in water depth of either < 100 or > 1000 m.As the distribution patterns of GDGTs reflect their biological sources and their respective habitats these can be identified from the sediment samples investigated. The distributions of branched GDGTs (brGDGTs) in the Yellow Sea (YS) was found to be similar to that of the lower Yellow River basin indicating that the brGDGTs in the YS originated from terrestrial soil. While the variability of the cyclisation ratio of branched tetraethers (CBT)-derived pH values in the Pearl River estuary (PRE) suggested that brGDGTs might also be produced in situ in coastal sediments or in the water column. In the shallow areas (water depth < 100 m, the YS, East China Sea and PRE) TEX86H-based SST (SST86H) was overestimated or underestimated when compared with mean annual SSTsatellite, most likely caused by seasonality or overprint by a cold-biased terrestrial signal. In the South China Sea (SCS), at water depth > 1000 m, the SST86Hmatched well the mean annual SST determined by satellite, indicating the applicability of the TEX86Htemperatures for paleoclimate investigations in these study areas and, potentially, in similar settings of deep water. These findings provide the basis for application of branched/isoprenoid index (BIT) and TEX86as indicators for temperature and paleotemperature in coastal and open marine environments around China.