The role of ponds in pesticide dissipation at the catchment scale: The case of the Save agricultural catchment (Southwestern France).

Pesticides are a major source of pollution for ecosystems. In agricultural catchments, ponds serve as buffer areas for pesticide transfers and biogeochemical hotspots for pesticide dissipation. Some studies have highlighted the specific impact of ponds on the dynamics of pesticides, but knowledge of their cumulative effect at the watershed scale is scarce.

Laboratory growth capacity of an invasive cyanobacterium () on organic substrates from surface waters of permafrost peatlands.

Within a global warming trend, invasive cyanobacteria, abundant in tropical and temperate regions, can migrate northward and colonize thermokarst lakes in permafrost-affected territories. For a better understanding of the cyanobacterial proliferation mechanism in those lakes, we performed laboratory growth of typical invasive cyanobacteria, , onto various organic-rich solutions representative of permafrost peatlands. Aqueous leachates of lichen, moss and peat were the most favorable substrates for massive growth.

Impact of freeze-thaw cycles on organic carbon and metals in waters of permafrost peatlands.

Despite the importance of soil and surface waters freezing in permafrost landscapes, the behaviour of dissolved organic carbon (DOC), nutrients and metals during periodic freeze-thaw cycles (FTC) remains poorly known. The on-going climate warming is likely to increase the frequency of FTC in continental aquatic settings, which could modify the chemical composition of waters. In this study, we conducted 9 repetitive cycles of overnight freezing (-20 °C) and 5 h thawing (4 °C) in the laboratory using representative 0.