On the biogeochemical response of a glacierized High Arctic watershed to climate change: Revealing patterns, processes and heterogeneity among micro-catchments

Our novel study examines landscape biogeochemical evolution following deglaciation and permafrost change in Svalbard by looking at the productivity of various micro-catchments existing within one watershed. It also sheds light on how moraine, talus and soil environments contribute to solute export from the entire watershed into the downstream marine ecosystem.

We find that solute dynamics in different micro-catchments are sensitive to abiotic factors such as runoff volume, water temperature, geology, geomorphological controls upon hydrological flowpaths and landscape evolution following sea level and glacial changes. Biotic factors influence the anionic composition of runoff because of the importance of microbial SO42− and NO3− production. The legacy of glaciation and its impact upon sea level changes is shown to influence local hydrochemistry, allowing Cl− to be used as a tracer of thawing permafrost that has marine origins. However, we show that a ‘glacial signal’ dominates solute export from the watershed. Therefore, although climatically driven change in the proglacial area has an influence on local ecosystems, the biogeochemical response of the entire watershed is dominated by glacially derived products of rapid chemical weathering. Consequently, only the study of micro-catchments existing within watersheds can uncover the landscape response to contemporary climate change.