Browsing by Author "Garreaud, R."

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    Recent Deoxygenation of Patagonian Fjord Subsurface Waters Connected to the Peru–Chile Undercurrent and Equatorial Subsurface Water Variability
    (American Geophysical Union, 2023-05-26) Linford, P.; Pérez-Santos, I.; Montes Torres, Ivonne; Dewitte, B.; Buchan, S.; Narváez, D.; Saldías, G.; Pinilla, E.; Garreaud, R.; Díaz, P.; Schwerter, C.; Montero, P.; Rodríguez-Villegas, C.; Cáceres-Soto, M.; Mancilla-Gutiérrez, G.; Altamirano, R.
    In recent decades, global dissolved oxygen (DO) measurements have registered a decrease of ∼1%–2% in oxygen content, raising concerns regarding the negative impacts of ocean deoxygenation on marine life and the greenhouse gas cycle. By combining in situ data from 2016 to 2022, satellite remote sensing, and outputs from a physical-biogeochemical model, we revealed the deoxygenation process in the Patagonian fjords for the first time. Deoxygenation was associated with the advection of equatorial subsurface water (ESSW) mass into the northern region of Patagonia. An analysis of the circulation regime using the Mercator-Ocean global high-resolution model confirmed the importance of the Peru–Chile undercurrent (PCUC) in transporting the ESSW poleward, contributing to the entrance of ESSW into the northern Patagonian fjords. A mooring system installed in the water interchange area between the Pacific Ocean and Patagonian fjords detected a decreasing DO of −21.66 μmol L⁻¹ over 7 years, which was explained by the increase in PCUC transport of 1.46 Sv. Inside the Puyuhuapi fjord system, a second DO time series exhibited more marked deoxygenation with −88.6 μmol L⁻¹ over 3 years linked with the influence of ESSW and local processes, such as DO consumption by the organic matter degradation. The recent deoxygenation registered in the northern Patagonian fjords demonstrates the significance of studying DO in the context of reducing the global oxygen content, further warranting the quantification of the impacts of deoxygenation on life cycles of marine organisms that inhabit the Patagonian fjords and channels and the Humboldt current system.
    Palabras clave:DeoxygenationHypoxiaWater masses
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    South Pacific Integrated Ecosystem Studies meeting: toward conservation and sustainable use of marine recources in the South Pacific
    (Wiley, 2016-04) Parada, C.; Frusher, S.; Bustamante, R. H.; Di Lorenzo, E.; Bernal, P.; Cryer, M.; Dunn, A.; Garreaud, R.; Gutierrez, M.; Jennings, S.; Montecinos, Aldo; Neira, S.; Quiñones, R. A.; Takahashi, Ken; Tascheri, R.; Yannicelli, B.
    The South Pacific region represents the world's largest oceanic water mass and plays a significant role in the earth's climate systems. This region also contains the largest group of island nations, most of whom are dependent on marine resources for their livelihoods. Several of the largest coastal and ocean fisheries also occur in this region (FAO, 2014). In addition, for the countries asscoiated with the southern Pacific Ocean region, the sea provides significant social, cualtural and economic benefits, with many countries being heavily reliant on both coastal and oceanic marine resources (Bell et al., 2013) . Increasing coastal populations and climate change are expected to augment human demands on already fully exploited or over-exploited marine resources, threatening both food security and suistanable livelihoods (Bell et al., 2011). Therefore, it is imperative that the science that describes and predicts linked biophysical and human systems is understood and developed to meet these needs. Climate change will have many impacts on marine ecosystems, with implications for end users including individuals, local communities, industries and governments. Improved scientific support for policy and management desicion-making in the face of these potential impacts is essential.
    Palabras clave:Marine resourcesClimate changeOceanography