Organic carbon and mercury exports from pan-Arctic rivers in a thawing permafrost context - A review.

Climate change affects more than elsewhere the northern circumpolar permafrost region. This zone comprises large rivers flowing mainly to the Arctic Ocean, delivering about 10 % of the global riverine water flux. These pan-Arctic Rivers drive the dynamics of northern organic carbon (OC) and mercury (Hg) cycling.

A combined microbial and biogeochemical dataset from high-latitude ecosystems with respect to methane cycle.

High latitudes are experiencing intense ecosystem changes with climate warming. The underlying methane (CH) cycling dynamics remain unresolved, despite its crucial climatic feedback. Atmospheric CH emissions are heterogeneous, resulting from local geochemical drivers, global climatic factors, and microbial production/consumption balance.

Anaerobic oxidation of methane and associated microbiome in anoxic water of Northwestern Siberian lakes.

Arctic lakes emit methane (CH) to the atmosphere. The magnitude of this flux could increase with permafrost thaw but might also be mitigated by microbial CH oxidation. Methane oxidation in oxic water has been extensively studied, while the contribution of anaerobic oxidation of methane (AOM) to CH mitigation is not fully understood.

Sub-oxycline methane oxidation can fully uptake CH produced in sediments: case study of a lake in Siberia.

It is commonly assumed that methane (CH) released by lakes into the atmosphere is mainly produced in anoxic sediment and transported by diffusion or ebullition through the water column to the surface of the lake. In contrast to that prevailing idea, it has been gradually established that the epilimnetic CH does not originate exclusively from sediments but is also locally produced or laterally transported from the littoral zone. Therefore, CH cycling in the epilimnion and the hypolimnion might not be as closely linked as previously thought.

Contribution of Peatland Permafrost to Dissolved Organic Matter along a Thaw Gradient in North Siberia.

Permafrost peatlands are important carbon stocks currently experiencing rapid evolution after permafrost thaw. Following thaw, dissolved organic matter (DOM) is a potentially important pathway for the release of permafrost carbon. This study investigates the origin and composition of DOM across sites at different stages of thaw in a discontinuous permafrost area of North Siberia.

Assessment of sediment and organic carbon exports into the Arctic ocean: The case of the Yenisei River basin.

The export of organic carbon export by the rivers to the oceans either as particulate organic carbon (POC) or dissolved organic carbon (DOC) is very sensitive to climate change especially in permafrost affected catchments where soils are very rich in organic carbon. With global warming, organic carbon export in both forms is expected to increase in Arctic regions. It should affect contemporary biogeochemical cycles in rivers and oceans and therefore modify the whole food web.

Eurasian river spring flood observations support net Arctic Ocean mercury export to the atmosphere and Atlantic Ocean.

Midlatitude anthropogenic mercury (Hg) emissions and discharge reach the Arctic Ocean (AO) by atmospheric and oceanic transport. Recent studies suggest that Arctic river Hg inputs have been a potentially overlooked source of Hg to the AO. Observations on Hg in Eurasian rivers, which represent 80% of freshwater inputs to the AO, are quasi-inexistent, however, putting firm understanding of the Arctic Hg cycle on hold.

People, pollution and pathogens - Global change impacts in mountain freshwater ecosystems.

Mountain catchments provide for the livelihood of more than half of humankind, and have become a key destination for tourist and recreation activities globally. Mountain ecosystems are generally considered to be less complex and less species diverse due to the harsh environmental conditions. As such, they are also more sensitive to the various impacts of the Anthropocene.

First assessment of water and carbon cycles in two tropical coastal rivers of south-west India: an isotopic approach.

Rationale: The contribution of tropical coastal rivers to the global carbon budget remains unmeasured, despite their high water dynamics, i.e. higher run-off with their basin characteristic of warm temperature.