The aliphatic hydrocarbon distributions of terrestrial plants around an alpine lake: a pilot study from Lake Ximencuo, Eastern Qinghai-Tibet Plateau

As part of an investigation of the sources of aliphatic hydrocarbons to the sediments of alpine Lake Ximencuo, leaves of the eight dominant vascular plants were collected and their hydrocarbon contents were analyzed. A series of unsaturated aliphatic hydrocarbons were identified in the plant leaves; in particular, Festuca sp. contain a series of n-alkadienes that have rarely been reported in previous studies. The comparison of n-alkane proxies (ACL27–33, ACLT, Paq, and CPI) and δ13Corg among plant leaves, surface soils, and lake sediments suggests that organic proxies have been altered to varying degrees during the transport and burial process of organic materials. It is believed that microbial reworking and source changes have great impacts on organic proxies in the alpine lake system. In addition, the cluster analysis for plant leaves depending on n-alkane compositions and the ACLT proxy generates similar results. Accordingly, we postulate that the average chain length of plant waxes might be a potential indicator of plant classification in regions such as the Qinghai-Tibet Plateau.