Understanding climate systems requires knowledge of climatic effects on C cycling and
greenhouse gas dynamics in coupled land-water-atmospheric systems, and in-turn, how these
feedback into the climate system. A major knowledge gap is to what extent C released from
permafrost soils is transported, processed and emitted as CO2 and CH4 in inland waters vs.
exported to downstream costal and ocean waters. Lakes and streams at high latitudes release
significant amounts of CO2 and CH4 to the atmosphere. These fluxes are largely controlled
by climate dependent factors (temperature, wind, precipitation) and hydrological flowpaths to
water bodies, either directly or via its regulation of the terrestrial production and export of
C6,7. Of particular importance is the organic C released from thawing permafrost which could
largely be metabolized leading to increased CO2 and CH4 emissions. C emission from
lakes and streams in areas of discontinuous permafrost has been shown to be comparable to
terrestrial atmospheric C exchange and to exceed downstream C export, implying an
important role of inland waters in the C cycle.

Despite these advances in our understanding of C fluxes in lakes and streams there is a
fundamental knowledge gap of climate impact on C transport and cycling in inland waters at
high latitudes, and especially when attempting to extrapolate and predict large scale patterns
and future trends. This is particularly true for the vast areas of boreal and arctic
Russia/Siberia.

This project proposes a comparative study of lake-stream networks across a climate gradient (boreal-arctic) in western Siberia (Fig. 2) covering a large range of permafrost conditions (absence-sporadic-discontinuous-continuous). The project includes (1) field surveys of CO2 and CH4 concentrations in approximately 50 lakes and 50 streams, and a more (2) detailed quantification of annual lateral and vertical C fluxes in selected catchments. Methods include a combination of manual and continuous measurements of dissolved organic and inorganic C, CO2, CH4 and gas transfer velocity (k) using chamber and logger techniques. Isotopic tracer (2H, 18O) sampling and modelling will allow hydrological transit times in each catchment and aquatic network to be estimated, and stream flow to be separated into different geographic sources of flow contribution within catchments16,17. Bioassay experiments18 will be used to assess temperature dependency in degradation rates, and in total bioavailability, of river DOC across the gradient. Additional measurements include depth, pH, nutrients, water temperature, wind, and discharge for each region. Most of the equipment needed is already available in the group. The project will have access to established field sites, digital maps of the region and to laboratory facilities at Tomsk State University, Russia.

The C footprint of the project will be minimized as far as possible by following the guidelines provided by JPI Climate website for travel, meetings, office and infrastructure. For this project it is of particular importance to minimize travel by virtual meetings, by having local staff for sampling, by planning meetings to minimize travel distances and to enable use of night trains.

Potential Impact:
Stakeholders and users: The proposed project tackles key uncertainties in the effects and feedbacks between changes in climate and permafrost dynamics and ecosystem biogeochemistry that are directly relevant to coupled GCMs used for predicting the consequences of climatic change; these are a primary tool to allow society, through its policy, to respond to, and anticipate, potential consequences of climate and environmental change. Hence the main beneficiaries will be northern government departments and their relevant agencies. The benefits would be improved modelling and hence more robust outputs and understanding leading to stronger evidence based policy decisions. The main route to dissemination to governments internationally is through IPCC and its scientific evidence base. Understanding the relationships between hydrology and ecosystem response is crucial for determining environmental standards for Water Framework Directives and assisting in the future development of ecologically based assessment tools.
High visibility by high quality publications, presentations, special sessions/workshops and networking is efficient means for knowledge transfer to the society (see details of these activities above). The webpage will be an addition channel for outreach to society. We will invite stakeholders to special sessions and to the workshop. We will also report to and interact with the Freshwater Ecosystem Monitoring Group (FEMG, Jan Karlsson is part of expert group lead from Sweden), an expert group within CAFF (Biodiversity working group of the Arctic Council) as we anticipate our results will have implications for understanding habitat properties of importance for freshwater organisms. Further, we will communicate the results of the project to the society via different outreach activities (regular public lectures and excursions during summer season) carried out at the Climate Impacts Research Centre (CIRC, Jan Karlsson is codirector).

Knowledge exchange-The project will actively interact with national and international colleagues (e.g. via IFBAR, THAW, HYDRA, VeWa mentioned above). International guest researchers will be invited to some project meetings to stimulate global knowledge transfer and connect to possible related efforts at other latitudes. This includes other related consortia within JPi Climate where there may be large potential for added value by collaboration and exchange of knowledge. An added value of the interdisciplinary and international nature of the project is training of postdoctoral, master and PhD students in state-of-the-art methods applied to environmental studies focused on tracing sources and fates of carbon in the environment. For placement funding we will approach the NERC policy placement programme, and bid to the NERC International Opportunities Fund. For engagement with schools outside of the fieldwork area, our past experience shows it is best to use STEM Ambassadors as one school is more willing to share comment through existing schools networks. Therefore schools visits will be arranged as part of STEM programme.