Links between stream water nitrogen and terrestrial vegetation in Northeast Greenland

The Arctic is warming and significant changes to the landscape, including increased vegetative cover (“greening”), are expected in the near future. These landscape changes may alter nitrogen (N) availability in terrestrial, stream, and coastal ecosystems, where production is often N limited, but the exact changes in nutrient cycling are uncertain. Here, we analyzed the relationship between vegetation greenness (i.e., NDVI) and dissolved inorganic (DIN) and organic (DON) concentrations in streams draining 14 headwater catchments (mean 3.6 km², range 0.4–11 km²) across three samplings in the Zackenberg area, Northeast Greenland. We found large variation in DIN and DON concentrations across the sampled streams. We further show that this variation is correlated to water temperature and catchment NDVI, such that increased vegetation greenness and temperature correlated with lower DIN, and increased greenness also correlated with higher DON concentrations in streams. The results suggest that increased terrestrial vegetation due to rising air temperature could substantially alter dissolved N concentrations and form in streams, with potentially cascading impacts on coastal areas.