Climate and Land Cover Trends Affecting Freshwater Inputs to a Fjord in Northwestern Patagonia

Freshwater inputs strongly influence oceanographic conditions in coastal systems of northwestern Patagonia (41–45°S). Nevertheless, the freshwater on these has weakened recent decades due to a marked decrease precipitation. Here we evaluate potential influences climate and land cover trends Puelo River (640 m 3 s –1 ), main source input Reloncaví Fjord (41.5°S). Water quality was analyzed along basin (six sampling points) at discharge site (1, 8, 25 depth), through six field campaigns carried out under contrasting streamflow scenarios. We also used several indicators hydrological alteration, cross-wavelet transform coherence analyses association between precipitation (1950–2019). Lastly, using WEAP model, maps (2001–2016) burned area reconstructions (1985–2019), simulated future impacts (2030) processes River. Total Nitrogen total phosphorus, dissolved carbon, iron concentrations measured river were 3–15 times lower than those fjord. Multivariate showed that drives carbon composition river. High contribute with humic colored materials, while low corresponded higher arrival protein-like materials from basin. The significant magnitude (lower summer autumn), duration (minimum annual streamflow), timing (more floods spring), frequency (fewer prolonged floods). change (LCC) analysis indicated more 90% maintained its cover, changes attributed large wildfires. Considering trends, simulations project slight increase mainly evapotranspiration. According previous simulations, projections present direction opposite forced by change. combined effect reduction fiords decline water highlights need for robust data LCC this river-fjord complex Patagonia.