Deciphering the impact of land-uses on terrestrial organic matter and mercury inputs to large boreal lakes of central Quebec using lignin biomarkers

作者：Moingt Matthieu^*; Lucotte Marc; Paquet Serge; Ghaleb Bassam

来源：Applied Geochemistry, 2014, 41: 34-48.

DOI：10.1016/j.apgeochem.2013.11.008

To evaluate watershed impacts of anthropogenic activities on terrestrial organic matter (TOM) and total mercury (THg) dynamics in large boreal lake ecosystems, we studied sediment cores retrieved in eight large lakes of Quebec (Canada). Two lakes with pristine watersheds were considered as reference lakes and six lakes with watersheds affected by different types of anthropogenic activities (e.g. logging and/or mining activities) were used to illustrate the influence of land-use on TOM and Hg cycling in lakes. A Geographical Information System (GIS) approach was used to correlate the evolution of anthropogenic land-uses from 1979 to 2010 (e.g. logging and mining activities) to TOM and THg contents measured in sediment cores. In each core, THg concentrations gradually increased over the recent years. Using lignin biomarkers, we noticed that the presence of both intense logging and mining activities in the watershed does not necessarily correspond to noticeable changes in the relative amount of terrestrial organic matter (TOM) exported from the watershed to the sediments and by extension to the level of THg measured in sediments. Apparently large-scale watersheds show some "buffering'' capacity to land-use disturbance.

• 出版日期2014-2