Lipid composition of particulate matter measured on water bottle samples during POLARSTERN cruise ARK-XI/1

The lipid composition of particulate matter in oceanic environments can provide informations on the nature and origin of the organic matter as well as on their transformation processes. Molecular characteristics for lipids in the Arctic environment have been used as indicators of the sources and transformation of organic particulate matter (Smith et al., 1997; Fahl and Stein, 1997, 1999). However, the features of the lipid composition of particulate matter in the Arctic with its high seasonality of ice Cover and primary productivity has been studied insufficiently.
Lipids are one of the most important compounds of organic matter. On the one hand, the composition of lipids is a result of the variability of biological sources (phyto- and zooplankton, higher plants, bacteria etc.). On the other hand, the lipid composition of particulate matter is undergone significant alteration during vertical transport. The organic matter balance in the Arctic marginal seas, such as the Kara and Laptev seas, is characterized by the significant supply of dissolved and particulate material by the major Eurasian rivers - Ob, Yenisei and Lena (Cauwet and Sidorov, 1996; Gordeev et al., 1996, Martin et al., 1993). In relation to the world's ocean the primary productivity values are lower in the Arctic seas due to the ice-cover. However local increased values of primary productivity can be connected with the melting processes inducing increased phytoplankton growth near ice-edge (Nelson et al., 1989; Fahl and Stein, 1997) and enhanced river supply of nutrients, These features can influence the proportion of allochtonous and autochtonous components of the organic matter in the Arctic marginal seas (Fahl and Stein, 1997; Stein and Fahl, 1999). Furthermore, increased lipid contents in aquatic environments were found near density discontinuities (Parish et al., 1988). Although being less informative than lipid studies on the molecular level the character of lipid composition analysis on the group could also be used for studying of particulate organic matter and its transformation in sedimentation processes in the Arctic. In this paper the investigation of the characteristics of lipid composition performed by Alexandrova and Shevchenko (1997) in Arctic seas was continued.

海洋环境中颗粒态物质的脂类组成，可提供有机质的性质、来源及其转化过程的相关信息。北极环境中脂类的分子特征，已被用作有机颗粒物质来源与转化的指示指标（Smith等，1997；Fahl与Stein，1997、1999）。然而，北极地区海冰覆盖与初级生产力具有高度季节性，其颗粒态物质脂类组成特征的相关研究尚不充分。
脂类是有机质中最重要的组成成分之一。一方面，脂类组成反映了生物来源的多样性，包括浮游植物、浮游动物、高等植物、细菌等；另一方面，颗粒态物质的脂类组成在垂直输运过程中会发生显著改变。北极边缘海（如喀拉海与拉普捷夫海）的有机质平衡，以欧亚大陆主要河流——鄂毕河、叶尼塞河与勒拿河——大量输入溶解态与颗粒态物质为典型特征（Cauwet与Sidorov，1996；Gordeev等，1996；Martin等，1993）。
相较于全球海洋，北极海域因海冰覆盖，初级生产力水平普遍偏低，但局部区域的初级生产力升高现象，可与融冰过程诱导的冰缘浮游植物增殖（Nelson等，1989；Fahl与Stein，1997）以及河流输入营养盐增多相关联。这些特征会影响北极边缘海有机质中异源与自源组分的占比（Fahl与Stein，1997；Stein与Fahl，1999）。
此外，研究发现在密度跃层附近的水生环境中，脂类含量会出现升高现象（Parish等，1988）。
尽管相较于分子层面的脂类研究，脂类的类群组成分析的信息量相对有限，但该方法仍可用于研究北极地区沉积过程中的颗粒态有机质及其转化过程。
本文延续了Alexandrova与Shevchenko（1997）在北极海域开展的脂类组成特征相关研究。