Understanding the Implications of Hydrographic Processes on the Dynamics of the Carbonate System in a Sub-Antarctic Marine-Terminating Glacier-Fjord (53°S)

The biogeochemical dynamics of fjords in the southeastern Pacific Ocean are strongly influenced by hydrological and oceanographic processes occurring at a seasonal scale. In this study, we describe role hydrographic forcing on variability carbonate system Sub-Antarctic glacial fjord, Seno Ballena, Strait Magellan (53°S). Biogeochemical variables were measured 2018 during three cruises (fall, winter spring) from high-frequency p CO 2 -pH mooring for 10 months ± 1 m depth fjord. data showed that freshwater input glacier adjacent surface layer fjord forced development undersaturated (< 400 ?atm) low aragonite saturation state (? Ar < 1) water. During spring, water had relatively (mean = 365, range: 167 - 471 ?atm), high pH 8.1 total proton concentration scale, 8.0 8.3), ? 1.6, 1.3 4.0). Concurrent measurements phytoplankton biomass nutrient conditions spring indicated periods lower values corresponded to higher photosynthesis rates, resulting autochthonous vertical mixing. contrast, (range: 365 – 433 T 8.1) 0.9 2.0) recorded cold waters fall. naturally ion concentrations diluted seawater decreased calcium depth, primary productivity caused relative increase . Assuming global climate change will bring further retreat ocean acidification, study represents important advances our understanding meltwater glacier–fjord systems.