Articoli di riviste: "Fjords de Patagonie"

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Díaz-Rosas, Francisco, Catharina Alves-de-Souza, Emilio Alarcón, Eduardo Menschel, Humberto E. González, Rodrigo Torres e Peter von Dassow. "Abundances and morphotypes of the coccolithophore <i>Emiliania huxleyi</i> in southern Patagonia compared to neighbouring oceans and Northern Hemisphere fjords". Biogeosciences 18, n. 19 (8 ottobre 2021): 5465–89. http://dx.doi.org/10.5194/bg-18-5465-2021.

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Abstract. Coccolithophores are potentially affected by ongoing ocean acidification, where rising CO2 lowers seawater pH and calcite saturation state (Ωcal). Southern Patagonian fjords and channels provide natural laboratories for studying these issues due to high variability in physical and chemical conditions. We surveyed coccolithophore assemblages in Patagonian fjords during late spring 2015 and early spring 2017. Surface Ωcal exhibited large variations driven mostly by freshwater inputs. High-Ωcal conditions (max. 3.6) occurred in the Archipelago Madre de Dios. Ωcal ranged from 2.0–2.6 in the western Strait of Magellan and 1.5–2.2 in the inner channel and was subsaturating (0.5) in Skyring Sound. Emiliania huxleyi was the only coccolithophore widely distributed in Patagonian fjords (> 96 % of total coccolithophores), only disappearing in the Skyring Sound, a semi-closed mesohaline system. Correspondence analysis associated higher E. huxleyi biomasses with lower diatom biomasses. The highest E. huxleyi abundances in Patagonia were in the lower range of those reported in Norwegian fjords. Predominant morphotypes were distinct from those previously documented in nearby oceans but similar to those of Norwegian fjords. Moderately calcified forms of E. huxleyi A morphotype were uniformly distributed throughout Patagonia fjords. The exceptional R/hyper-calcified coccoliths, associated with low Ωcal values in Chilean and Peruvian coastal upwellings, were a minor component associated with high Ωcal levels in Patagonia. Outlying mean index (OMI) niche analysis suggested that pH and Ωcal conditions explained most variation in the realized niches of E. huxleyi morphotypes. The moderately calcified A morphotype exhibited the widest niche breadth (generalist), while the R/hyper-calcified morphotype exhibited a more restricted realized niche (specialist). Nevertheless, when considering an expanded sampling domain, including nearby southeast Pacific coastal and offshore waters, even the R/hyper-calcified morphotype exhibited a higher niche breadth than other closely phylogenetically related coccolithophore species. The occurrence of E. huxleyi in naturally low pH–Ωcal environments indicates that its ecological response is plastic and capable of adaptation.

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Ross, Lauren, Iván Pérez-Santos, Brigitte Parady, Leonardo Castro, Arnoldo Valle-Levinson e Wolfgang Schneider. "Glacial Lake Outburst Flood (GLOF) Events and Water Response in A Patagonian Fjord". Water 12, n. 1 (16 gennaio 2020): 248. http://dx.doi.org/10.3390/w12010248.

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As a result of climate change, the frequency of glacial lake outburst floods (GLOF) is increasing in Chilean Patagonia. Yet, the impacts of the flood events on the physics and biology of fjords is still unknown. Current velocities, density, in-situ zooplankton samples, and volume backscatter (Sv) derived from an acoustic profiler were used to explore the response of circulation and zooplankton abundance in a Patagonian fjord to GLOF events in 2010 and 2014. Maximum Sv was found both during the GLOFs and in late winter to early spring of 2010 and the fall and summer of 2014. The increase in Sv in late winter and spring of 2010 corresponded to multiple zooplankton species found from in-situ net sampling. In addition, diel vertical migrations were found during this seasonal increase both qualitatively and in a spectral analysis. Concurrently with zooplankton increases, wind forcing produced a deepening of the pycnocline. Zooplankton abundance peaked in the fjord when the pycnocline depth deepened due to wind forcing and throughout the entire spring season, indicating that mixing conditions could favor secondary production. These results were corroborated by the 2014 data, which indicate that weather events in the region impact both fjord physics and ecology.

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Pérez-Santos, Iván, Leonardo Castro, Lauren Ross, Edwin Niklitschek, Nicolás Mayorga, Luis Cubillos, Mariano Gutierrez et al. "Turbulence and hypoxia contribute to dense biological scattering layers in a Patagonian fjord system". Ocean Science 14, n. 5 (9 ottobre 2018): 1185–206. http://dx.doi.org/10.5194/os-14-1185-2018.

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Abstract. The aggregation of plankton species along fjords can be linked to physical properties and processes such as stratification, turbulence and oxygen concentration. The goal of this study is to determine how water column properties and turbulent mixing affect the horizontal and vertical distributions of macrozooplankton along the only northern Patagonian fjord known to date, where hypoxic conditions occur in the water column. Acoustic Doppler current profiler moorings, scientific echo-sounder transects and in situ plankton abundance measurements were used to study macrozooplankton assemblages and migration patterns along Puyuhuapi Fjord and Jacaf Channel in Chilean Patagonia. The dissipation of turbulent kinetic energy was quantified through vertical microstructure profiles collected throughout time in areas with high macrozooplankton concentrations. The acoustic records and in situ macrozooplankton data revealed diel vertical migrations (DVM) of siphonophores, chaetognaths and euphausiids. In particular, a dense biological backscattering layer was observed along Puyuhuapi Fjord between the surface and the top of the hypoxic boundary layer (∼100 m), which limited the vertical distribution of most macrozooplankton and their DVM, generating a significant reduction of habitat. Aggregations of macrozooplankton and fishes were most abundant around a submarine sill in Jacaf Channel. In this location macrozooplankton were distributed throughout the water column (0 to ∼200 m), with no evidence of a hypoxic boundary due to the intense mixing near the sill. In particular, turbulence measurements taken near the sill indicated high dissipation rates of turbulent kinetic energy (ε∼10-5 W kg−1) and vertical diapycnal eddy diffusivity (Kρ∼10-3 m2 s−1). The elevated vertical mixing ensures that the water column is well oxygenated (3–6 mL L−1, 60 %–80 % saturation), creating a suitable environment for macrozooplankton and fish aggregations. Turbulence induced by tidal flow over the sill apparently enhances the interchange of nutrients and oxygen concentrations with the surface layer, creating a productive environment for many marine species, where the prey–predator relationship might be favored.

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Linford, Pamela, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera et al. "Oceanographic processes driving low-oxygen conditions inside Patagonian fjords". Biogeosciences 21, n. 6 (20 marzo 2024): 1433–59. http://dx.doi.org/10.5194/bg-21-1433-2024.

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Abstract. The dissolved oxygen (DO) levels of coastal ocean waters have decreased over the last few decades in part because of the increase in surface and subsurface water temperature caused by climate change, the reduction in ocean ventilation, and the increase in stratification and eutrophication. In addition, biological and human activity in coastal zones, bays, and estuaries has contributed to the acceleration of current oxygen loss. The Patagonian fjord and channel system is one world region where low-DO water (LDOW, 30 %–60 % oxygen saturation) and hypoxia conditions (<30 % oxygen saturation, 2 mL L−1 or 89.2 µmol L−1) are observed. An in situ dataset of hydrographic and biogeochemical variables (1507 stations), collected from sporadic oceanographic cruises between 1970 and 2021, was used to evaluate the mechanisms involved in the presence of LDOW and hypoxic conditions in northern Patagonian fjords. Results denoted areas with LDOW and hypoxia coinciding with the accumulation of inorganic nutrients and the presence of salty and oxygen-poor Equatorial Subsurface Water mass. The role of biological activity in oxygen reduction was evident in the dominance of community respiration over gross primary production. This study elucidates the physical and biogeochemical processes contributing to hypoxia and LDOW in the northern Patagonian fjords, highlighting the significance of performing multidisciplinary research and combining observational and modeling work. This approach underscores the importance of a holistic understanding of the subject, encompassing both real-world observations and insights provided by modeling techniques.

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Bao, Weiyang, e Carlos Moffat. "Impact of shallow sills on circulation regimes and submarine melting in glacial fjords". Cryosphere 18, n. 1 (9 gennaio 2024): 187–203. http://dx.doi.org/10.5194/tc-18-187-2024.

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Abstract. The increased melting and rapid retreat of marine-terminating glaciers is a key contributor to sea-level rise. In glacial fjords with shallow sills common in Patagonia, Alaska, and other systems, these bathymetric features can act as a first-order control on the dynamics. However, our understanding of how this shallow bathymetry interacts with the subglacial discharge from the glacier and impacts the fjord circulation, water properties, and rates of submarine melting is limited. To address this gap, we conduct idealized numerical simulations using a coupled plume–ocean fjord model spanning a wide range of initial ocean conditions, sill depths, and subglacial discharge. A previously documented circulation regime leads to strong mixing and vertical transport over the sill, where up to ∼ 70 % of the colder water from the upper-layer outflow is refluxed into the deeper layer, cooling the incoming warm oceanic water by as much as 1 ∘C and reducing the stratification near the glacier front. When the initial stratification is relatively strong or the subglacial discharge is relatively weak, an additional unsteady circulation regime arises where the freshwater flow can become trapped below the sill depth for weeks to months, creating an effective cooling mechanism for the deep water. We also find that submarine melting often increases when a shallow sill is added to a glacial fjord due to the reduction of stratification – which increases submarine melting – dominating over the cooling effect as the oceanic inflow is modified by the presence of the sill. These results underscore that shallow-silled fjords can have distinct dynamics that strongly modulate oceanic properties and the melting rates of marine-terminating glaciers.

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de la Torriente, Ana, Renato A. Quiñones, Diego A. Miranda-Urbina e Fidel Echevarría. "South American sea lion and spiny dogfish predation on artisanal catches of southern hake in fjords of Chilean Patagonia". ICES Journal of Marine Science 67, n. 2 (16 ottobre 2009): 294–303. http://dx.doi.org/10.1093/icesjms/fsp235.

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Abstract de la Torriente, A., Quiñones, R. A., Miranda-Urbina, D. A., and Echevarría, F. 2010. South American sea lion and spiny dogfish predation on artisanal catches of southern hake in fjords of Chilean Patagonia. – ICES Journal of Marine Science, 67: 294–303. The South American sea lion (Otaria flavescens) is a pinniped known to interact with fisheries, potentially damaging gear and lowering catches. Predation by O. flavescens and spiny dogfish (Squalus acanthias) on artisanal southern hake (Merluccius australis) catches in fjords of Chilean Patagonia is estimated and compared. Observations were made in the Gulf of Ancud and Comau Fjord in southern Chile from October 2005 to September 2006. Losses of southern hake catches to O. flavescens predation were 1.6% of the total catch of the species, and to spiny dogfish predation were slightly higher, at 3.3%. The predation of both species on southern hake catches varied throughout the year, but was lower in summer. Both predators showed a preference for adult southern hake over juveniles. There was no significant relationship between predation on southern hake catches by the sea lion and the availability of adult and juvenile southern hake on longlines (AHCL). However, there was a significant relationship (p < 0.05) between AHCL and spiny dogfish predation. Most O. flavescens interaction events (81.4%) were during longline retrieval. Our results showed minimal interactions between O. flavescens and the artisanal southern hake fishery in the area, so with the present abundance of O. flavescens, there is no justification for reducing the sea lion population by hunting.

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Ahumada, Ramón, Elizabeth González, Christian Díaz e Nelson Silva. "Characterization of Baker Fjord region through its heavy metal content on sediments (Central Chilean Patagonia)". Latin American Journal of Aquatic Research 43, n. 3 (23 febbraio 2017): 581–87. http://dx.doi.org/10.3856/vol43-issue3-fulltext-20.

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The spatial distribution of heavy metals content (Ba, Cd, Cu, Pb, Sr and Zn) in sediments of the Baker Fjord and surrounding channels in the central region of the Chilean fjords (47°45'S, 48°15'S) is analyzed. The aim of the study was characterized the patterns of abundance and distribution of these metals in surface sediments. The area corresponds to a poorly studied zone with low human activity. Distribution patterns would be influenced by rainfall conditions (local erosion), fluvial (continental sediments carried by rivers), glacier (glacier flour) and estuarine circulation. Cluster analysis allows differentiation among the sampled sites and group with similar characteristics. Finally, the concentrations found were contrasted with average values of metamorphic rocks and show with some certainty that the values found for calendar for this area and the greatest concentrations are the result of natural enrichment.

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Soto, Eulogio H., e Guillermo San Martín. "New reports and a new species of Syllidae (Annelida) from Chilean Patagonia". Journal of the Marine Biological Association of the United Kingdom 98, n. 7 (24 luglio 2017): 1599–607. http://dx.doi.org/10.1017/s0025315417001242.

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The Syllidae subfamilies Eusyllinae, Anoplosyllinae and Autolytinae, as well as the incertae sedis genera (Aguado et al., 2012), were studied from samples collected in shallow water from fjords and channels in Chilean Patagonia. One new species Paraehlersia kawesqar sp. nov. is described. The genus Nudisyllis Knox & Cameron, 1970 is recorded for the first time for Chile, while the species Brachysyllis infuscata (Ehlers, 1901a) and Syllides japonica Imajima, 1966 are recorded for the first time for continental Chile. Finally, Syllides articulosa Ehlers, 1897 and Epigamia sp. are also reported. The majority of the species were found inside tubes of the polychaete worm Chaetopterus cf. variopedatus (Renier, 1804) – a new habitat for syllid polychaetes. This work is an important contribution to the knowledge of syllids in Chile and to the polychaete fauna of the Patagonian region generally.

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Rebolledo, Lorena, Carina B. Lange, Sébastien Bertrand, Práxedes Muñoz, Marco Salamanca, Pablo Lazo, José L. Iriarte, Gabriel Vargas, Silvio Pantoja e Laurent Dezileau. "Late Holocene precipitation variability recorded in the sediments of Reloncaví Fjord (41°S, 72°W), Chile". Quaternary Research 84, n. 1 (luglio 2015): 21–36. http://dx.doi.org/10.1016/j.yqres.2015.05.006.

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We present reconstructions of late Holocene changes in the source of organic matter and siliceous export production in the Relocanví Fjord (41°S, 72°W), Northern Chilean Patagonia, based on organic carbon content, δ13Corg, N/C ratio, diatom assemblages and biogenic silica contents from three sediment cores. The age models are based on a combination of 210Pb profiles, AMS 14C dating, and on the first occurrence of the diatom Rhizosolenia setigera f. pungens, as a stratigraphic marker in the fjords. The cores span the last 300 to 700 yr. Diatoms dominate the siliceous assemblages in the three cores (98% on average). Our results suggest that precipitation seasonality in the region of Reloncaví was high in CE 1300–1400 and CE 1700–1850, with a clear decreasing trend since CE 1850. The latter trend is in agreement with instrumental records and tree-ring reconstructions. These fluctuations seem to be associated with the Southern Annular Mode (SAM).

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Friedlander, Alan M., Enric Ballesteros, Jennifer E. Caselle, Mathias Hüne, Alyssa M. Adler e Enric Sala. "Patterns and drivers of benthic macroinvertebrate assemblages in the kelp forests of southern Patagonia". PLOS ONE 18, n. 1 (6 gennaio 2023): e0279200. http://dx.doi.org/10.1371/journal.pone.0279200.

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The kelp forests of southern Patagonia have a large diversity of habitats, with remote islands, archipelagos, peninsulas, gulfs, channels, and fjords, which are comprised of a mixture of species with temperate and sub-Antarctic distributions, creating a unique ecosystem that is among the least impacted on Earth. We investigated the distribution, diversity, and abundance of marine macroinvertebrate assemblages from the kelp forests of southern Patagonia over a large spatial scale and examined the environmental drivers contributing to the observed patterns in assemblage composition. We analyzed data from 120 quantitative underwater transects (25 x 2 m) conducted within kelp forests in the southern Patagonian fjords in the Kawésqar National Reserve (KNR), the remote Cape Horn (CH) and Diego Ramírez (DR) archipelagos of southern Chile, and the Mitre Peninsula (MP) and Isla de los Estados (IE) in the southern tip of Argentina. We observed rich assemblages of macroinvertebrates among these kelp forests, with a total of 185 unique taxa from 10 phyla and 23 classes/infraorders across the five regions. The number of taxa per transect was highest at IE, followed by MP, CH, and KNR, with the lowest number recorded at DR. The trophic structure of the macroinvertebrate assemblages was explained mostly by wave exposure (28% of the variation), followed by salinity (12%) and the KNR region (11%). KNR was most distinct from the other regions with a greater abundance of deposit feeders, likely driven by low salinity along with high turbidity and nutrients from terrigenous sources and glacial melt. Our study provides the first broad-scale description of the benthic assemblages associated with kelp forests in this vast and little-studied region and helps to establish baselines for an area that is currently lightly influenced by local anthropogenic factors and less impacted by climate change compared with other kelp forests globally.

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Medina-Vogel, Gonzalo, Carlos Calvo-Mac, Nicole Delgado-Parada, Gabriela Molina-Maldonado, Stephanie Johnson-Padilla e Paulette Berland-Arias. "Co-Occurrence Between Salmon Farming, Alien American Mink (Neogale vison), and Endangered Otters in Patagonia". Aquatic Mammals 49, n. 6 (15 novembre 2023): 561–68. http://dx.doi.org/10.1578/am.49.6.2023.561.

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The southern river otter (Lontra provocax) and the marine otter (Lontra felina) are endangered species that inhabit Chile. In southern Chile, both species cohabit with the American mink (Neogale vison), an invasive exotic species. The Chilean aquaculture industry has grown exponentially since the late 1980s, with salmon farming taking place from central Chile to the Patagonian fjords and channels. This study assessed co-occurrence between otters, mink, and aquaculture in Patagonia by (1) distributing a survey among workers, fisheries personnel, and aquaculture inspectors concerning observations of otters and mink inside or around aquaculture facilities and outcomes; and (2) a geographical assessment of distribution overlap between known otter territory and salmon farming-registered facilities. We recorded the first anecdotal evidence of interaction, described as co-occurrence, among native otters, American mink, and salmon aquaculture in Patagonia, which varied among seasons and seems to be increasing. We also recorded evidence of difficulty in recognition of the three mustelids among respondents. There is a geographically extended interaction between otters and salmon farms in Chile. The evidence of interaction among alien American mink, native endangered otters, and aquaculture is an early alarm for human–wildlife conflict, and further studies are recommended to ensure native otter conservation.

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Silva, Nelson, e Cristian A. Vargas. "Hypoxia in Chilean Patagonian Fjords". Progress in Oceanography 129 (dicembre 2014): 62–74. http://dx.doi.org/10.1016/j.pocean.2014.05.016.

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BERTOLINO, MARCO, GABRIELE COSTA, ANNA REBOA, GIORGIO BAVESTRELLO, MAURIZIO PANSINI, FEDERICO BETTI, MARZIA BO e GIOVANNI DANERI. "The sponge fauna of the Seno Magdalena and Puyuhuapi Fjord (Chile), with a description of two new species". Zootaxa 4623, n. 2 (25 giugno 2019): 306–20. http://dx.doi.org/10.11646/zootaxa.4623.2.5.

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The presence of fjords, islands and channels originating from glacial erosion and ice cap retreat, makes the Chilean benthic biodiversity difficult to explore and study. Our survey of this region allowed the identification of 29 Demospongiae species in total. Two of them are new to science and here described: Biemna lutea sp. nov., and Hamigera cleistochela sp. nov.. Two species (Clathria (Clathria) microxa and Lissodendoryx (Ectyodoryx) patagonica,) are new for the region and the Chilean fjords. Lissodendoryx (Ectyodoryx) patagonica was found for the second time after the original description by Ridley & Dendy, 132 years ago. These results – considering the small number of species identified on the whole – are promising and confirm that the marine biodiversity of Chilean fjords is remarkable but not well known yet.

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Viddi, Francisco A., Rodrigo Hucke-Gaete, Juan P. Torres-Florez e Sandra Ribeiro. "Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile". ICES Journal of Marine Science 67, n. 5 (10 gennaio 2010): 959–70. http://dx.doi.org/10.1093/icesjms/fsp288.

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Abstract Viddi, F. A., Hucke-Gaete, R., Torres-Florez, J. P., and Ribeiro, S. 2010. Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile. – ICES Journal of Marine Science, 67: 959–970. Compared with other Chilean coastal areas, little is known about the diversity and distribution of cetaceans in northern Patagonian fjords. Between December 2000 and November 2001, surveys on platforms of opportunity were undertaken in southern Chile to evaluate species richness and the spatial and seasonal distribution of cetaceans. Nine species were recorded, blue, humpback, and minke whales, Peale's dolphin, Chilean dolphin, killer whale, false killer whale, bottlenose dolphin, and Cuvier's beaked whale. The pattern of cetacean distribution displayed significant seasonal differences, with most baleen whales (mysticetes) observed during late summer and autumn, and toothed cetaceans (odontocetes) mostly during spring. Generalized additive models, used to assess the spatial distribution of cetaceans, showed that mysticetes were distributed disproportionately along a north–south gradient, in open gulfs with oceanic influence, and close to shore. In contrast, odontocetes were observed mainly within narrow channels, areas with complex coastal morphology, peaking at different water depths. These findings, although from a single year of data, increase our understanding of habitat determinants of cetacean distribution in southern Chile. The results have the potential to be applied to coastal conservation and management in the region.

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Wils, Katleen, Marlies Wermersche, David Van Rooij, Galderic Lastras, Frank Lamy, Helge W. Arz, Giuseppe Siani, Sebastien Bertrand e Maarten Van Daele. "Late Holocene current patterns in the northern Patagonian fjords recorded by sediment drifts in Aysén Fjord". Marine Geology 441 (novembre 2021): 106604. http://dx.doi.org/10.1016/j.margeo.2021.106604.

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Dowdeswell, J. A., E. K. Dowdeswell e C. Rodrigo. "Pockmarks in the fjords of Chilean Patagonia". Geological Society, London, Memoirs 46, n. 1 (2016): 109–10. http://dx.doi.org/10.1144/m46.159.

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Rivera, A., M. Koppes, C. Bravo e J. C. Aravena. "Little Ice Age advance and retreat of Glaciar Jorge Montt, Chilean Patagonia". Climate of the Past 8, n. 2 (5 marzo 2012): 403–14. http://dx.doi.org/10.5194/cp-8-403-2012.

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Abstract. Glaciar Jorge Montt (48°20' S/73°30' W), one of the main tidewater glaciers of the Southern Patagonian Icefield (SPI), has experienced the greatest terminal retreat observed in Patagonia during the past century, with a recession of 19.5 km between 1898 and 2011. This retreat has revealed trees laying subglacially until 2003. These trees were dated using radiocarbon, yielding burial ages between 460 and 250 cal yrs BP. The presence of old growth forest during those dates indicates that Glaciar Jorge Montt was upvalley of its present position before the commonly recognized Little Ice Age (LIA) period in Patagonia. The post-LIA retreat was most likely triggered by climatically induced changes during the 20th century; however, Glaciar Jorge Montt has responded more dramatically than its neighbours. The retreat of Jorge Montt opened a 19.5 km long fjord since 1898, which reaches depths in excess of 390 m. The bathymetry is well correlated with glacier retreat rates, suggesting that dynamic responses of the glacier are at least partially connected to near buoyancy conditions at the ice front, resulting in high calving fluxes, accelerating thinning rates and rapid ice velocities.

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Sauter, Tobias. "Revisiting extreme precipitation amounts over southern South America and implications for the Patagonian Icefields". Hydrology and Earth System Sciences 24, n. 4 (23 aprile 2020): 2003–16. http://dx.doi.org/10.5194/hess-24-2003-2020.

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Abstract. Patagonia is thought to be one of the wettest regions on Earth, although available regional precipitation estimates vary considerably. This uncertainty complicates understanding and quantifying the observed environmental changes, such as glacier recession, biodiversity decline in fjord ecosystems and enhanced net primary production. The Patagonian Icefields, for example, are one of the largest contributors to sea-level rise outside the polar regions, and robust hydroclimatic projections are needed to understand and quantify current and future mass changes. The reported projections of precipitation from numerical modelling studies tend to overestimate those from in situ determinations, and the plausibility of these numbers has never been carefully scrutinized, despite the significance of this topic to our understanding of observed environmental changes. Here I use simple physical arguments and a linear model to test the plausibility of the current precipitation estimates and its impact on the Patagonian Icefields. The results show that environmental conditions required to sustain a mean precipitation amount exceeding 6.09±0.64 m yr−1 are untenable according to the regional moisture flux. The revised precipitation values imply a significant reduction in the surface mass balance of the Patagonian Icefields compared to previously reported values. This yields a new perspective on the response of Patagonia's glaciers to climate change and their sea-level contribution and might also help reduce uncertainties in the change of other precipitation-driven environmental phenomena.

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Rivera, A., M. Koppes, C. Bravo e J. C. Aravena. "Little ice age advance and retreat of Glaciar Jorge Montt, Chilean Patagonia, recorded in maps, air photographs and dendrochronology". Climate of the Past Discussions 7, n. 5 (5 ottobre 2011): 3131–64. http://dx.doi.org/10.5194/cpd-7-3131-2011.

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Abstract. Glaciar Jorge Montt (48°20' S/73°30' W), one of the main tidewater glaciers of the Southern Patagonian Icefield (SPI), has experienced the fastest frontal retreat observed in Patagonia during the past century, with a recession of 19.5 km between 1898 and 2011. This record retreat uncovered trees overridden during the Little Ice Age (LIA) advance of the glacier. Samples of these trees were dated using radiocarbon methods, yielding burial ages between 460 and 250 cal yr BP. The dendrochronology and maps indicate that Glaciar Jorge Montt was at its present position before the beginning of the LIA, in concert with several other glaciers in Southern Patagonia, and reached its maximum advance position between 1650 and 1750 AD. The post-LIA retreat is most likely triggered by climatically induced changes during the 20th century, however, Glaciar Jorge Montt has responded more dramatically than its neighbours. The retreat of Jorge Montt opened a new fjord 19.5 km long, and up to 391 m deep, with a varied bathymetry well correlated with glacier retreat rates, suggesting that dynamic responses of the glacier are at least partially connected to near buoyancy conditions at the ice front, resulting in high calving fluxes, accelerating thinning rates and rapid ice velocities.

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Giesecke, R., J. Höfer, T. Vallejos e H. E. González. "Death in southern Patagonian fjords: Copepod community structure and mortality in land- and marine-terminating glacier-fjord systems". Progress in Oceanography 174 (maggio 2019): 162–72. http://dx.doi.org/10.1016/j.pocean.2018.10.011.

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Molinet, Carlos, Edwin J. Niklitschek, Susana Coper, Manuel Diaz, Patricio A. Diaz, Monica Fuentealba e Francisca Marticorena. "Challenges for coastal zoning and sustainable development in the northern Patagonian fjords (Aysen, Chile)". Latin American Journal of Aquatic Research 42, n. 1 (10 marzo 2014): 18–29. http://dx.doi.org/10.3856/vol42-issue1-fulltext-2.

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Palma, Sergio, María Cristina Retamal, Nelson Silva e Claudio Silva. "Horizontal and vertical distributions of siphonophores in relation to oceanographic conditions in Chilean Patagonian fjords". Scientia Marina 78, n. 3 (28 agosto 2014): 339–51. http://dx.doi.org/10.3989/scimar.03966.04b.

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Pérez-Santos, Iván, José Garcés-Vargas, Wolfgang Schneider, Lauren Ross, Sabrina Parra e Arnoldo Valle-Levinson. "Double-diffusive layering and mixing in Patagonian fjords". Progress in Oceanography 129 (dicembre 2014): 35–49. http://dx.doi.org/10.1016/j.pocean.2014.03.012.

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24

Cuevas, María José, Konrad Górski, Leonardo R. Castro, Aurélien Vivancos e Malcolm Reid. "Otolith elemental composition reveals separate spawning areas of anchoveta, Engraulis ringens, off central Chile and northern Patagonia". Scientia Marina 83, n. 4 (3 dicembre 2019): 317. http://dx.doi.org/10.3989/scimar.04918.28a.

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Abstract (sommario):

The anchoveta (Engraulis ringens) is widely distributed throughout the Humboldt Current (4°30′-44°S). In recent years, its eggs and larvae have also been found inside fjords and channels of northern Patagonia, close to the southern limit of the central-south Chilean fishery zone. Currently, it is unclear whether these southern individuals constitute an independent subpopulation. This study analysed the elemental composition of otoliths from 102 specimens from central Chile and northern Patagonia using laser ablation inductively coupled plasma mass spectrometry. The results indicated that the elemental composition of the otolith cores (Mg, Pb, Zn, Ba) differed significantly between sites, revealing the existence of two discrete spawning zones, one in central Chile and one in northern Patagonia. However, the low significant differences of elemental signatures of otolith edges suggest that either individuals from both areas move between spawning areas and mix at certain periods of the year, or they represent pocket units that form part of a larger stock that moves along the coast.

25

SOTO, EULOGIO H., e GUILLERMO SAN MARTÍN. "Exogoninae (Annelida: Syllidae) from Chilean Patagonia". Zootaxa 4353, n. 3 (24 novembre 2017): 521. http://dx.doi.org/10.11646/zootaxa.4353.3.7.

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The subfamily Exogoninae was studied from samples collected in shallow waters of the fjords and channels of the Patagonian region of Chile. Two new species are described: Exogone yagan n. sp. and Erinaceusyllis carrascoi n. sp. The species Exogone heterosetoides, Erinaceusyllis bidentata and Erinaceusyllis perspicax are newly reported to Chile, as well as the genus Erinaceusyllis San Martín, 2005. Parapionosyllis brevicirra, Sphaerosyllis hirsuta and Salvatoria rhopalophora, n. comb., are also reported, with the latter redescribed. Finally, we redescribe Exogone anomalochaeta from Antarctica. Most of the species were found inside tubes of Chaetopterus cf. variopedatus; this habitat is new for Exogoninae. This research is a new taxonomic account of Syllidae in Chile and improves the knowledge of Exogoninae of the Patagonian region.

26

Mutschke, Erika, e Matthias Gorny. "The benthic decapod fauna in the channels and fjords along the South Patagonian Icefield, Southern Chile". Scientia Marina 63, S1 (30 dicembre 1999): 315–19. http://dx.doi.org/10.3989/scimar.1999.63s1315.

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27

Mohr, Christian H., Oliver Korup, Héctor Ulloa e Andrés Iroumé. "Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords". Global Biogeochemical Cycles 31, n. 11 (novembre 2017): 1626–38. http://dx.doi.org/10.1002/2017gb005647.

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28

Valdés-Castro, Valentina, Humberto E. González, Ricardo Giesecke, Camila Fernández e Verónica Molina. "Assessment of Microbial Community Composition Changes in the Presence of Phytoplankton-Derived Exudates in Two Contrasting Areas from Chilean Patagonia". Diversity 14, n. 3 (7 marzo 2022): 195. http://dx.doi.org/10.3390/d14030195.

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Abstract (sommario):

Patagonian fjords and channels in southern Chile are heterogeneous ecosystems characterized by the interaction of estuarine and marine waters influencing physical-chemical conditions and biological assemblages. Besides salinity, microbial communities from estuarine and marine origin are naturally subjected to changing organic matter quality and variable nutrient concentrations. In this study, we tackle the response of the bacterial community from estuarine and marine origins associated with two size classes (<0.7 µm and <1.6 µm) to the addition of sterile phytoplankton-derived exudates (PDE) compared to control conditions (no addition). Picoplanktonic cell abundance, active bacterial composition analyzed through 16S rRNA sequencing, changes in dissolved organic carbon (DOC) and δ13C were determined over 5 and 15 days after PDE addition. Our results showed that the active marine bacteria were richer and more diverse than their estuarine counterparts, and were dominated by Alphaproteobacteria and Gammaproteobacteria, respectively. PDE addition in both the fractions and the sample origin resulted in an enrichment throughout the incubation of Rhodobacteracea and Cryimorphaceae families, whereas Epsilonproteobacteria (Arcobacteraceae) were mainly favored in the estuarine experiments. Picoplankton abundance increased with time, but higher cell numbers were found in PDE treatments in both size classes (>2 × 105 cell mL−1). In all the experiments, DOC concentration decreased after eight days of incubation, but shifts in δ13C organic matter composition were greater in the estuarine experiments. Overall, our results indicate that despite their different origins (estuarine versus marine), microbial communities inhabiting the fjord responded to PDE with a faster effect on marine active bacteria.

29

Meier, Aravena, Grießinger, Hochreuther, Soto-Rogel, Zhu, Pol-Holz, Schneider e Braun. "Late Holocene Glacial Fluctuations of Schiaparelli Glacier at Monte Sarmiento Massif, Tierra del Fuego (54°24′S)". Geosciences 9, n. 8 (3 agosto 2019): 340. http://dx.doi.org/10.3390/geosciences9080340.

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The Magallanes–Tierra del Fuego region, Southern Patagonia (53–56°S) features a plethora of fjords and remote and isolated islands, and hosts several thousand glaciers. The number of investigated glaciers with respect to the multiple Neoglacial advances is based on a few individual studies and is still fragmentary, which complicates the interpretation of the glacial dynamics in the southernmost part of America. Schiaparelli Glacier (54°24′S, 70°50′W), located at the western side of the Cordillera Darwin, was selected for tree-ring-based and radiocarbon dating of the glacial deposits. One focus of the study was to address to the potential dating uncertainties that arise by the use of Nothofagus spp. as a pioneer species. A robust analysis of the age–height relationship, missing the pith of the tree (pith offset), and site-specific ecesis time revealed a total uncertainty value of ±59 years. Three adjacent terminal moraines were identified, which increasingly tapered towards the glacier, with oldest deposition dates of 1749 ± 5 CE, 1789 ± 5 CE, and 1867 ± 5 CE. Radiocarbon dates of trunks incorporated within the terminal moraine system indicate at least three phases of cumulative glacial activity within the last 2300 years that coincide with the Neoglacial phases of the Southern Patagonian Icefield and adjacent mountain glaciers. The sub-recent trunks revealed the first evidence of a Neoglacial advance between ~600 BCE and 100 CE, which so far has not been substantiated in the Magallanes–Tierra del Fuego region.

30

Baldrich, Ángela M., Patricio A. Díaz, Gonzalo Álvarez, Iván Pérez-Santos, Camila Schwerter, Manuel Díaz, Michael Araya et al. "Dinophysis acuminata or Dinophysis acuta: What Makes the Difference in Highly Stratified Fjords?" Marine Drugs 21, n. 2 (19 gennaio 2023): 64. http://dx.doi.org/10.3390/md21020064.

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Dinophysis acuminata and D. acuta, which follows it seasonally, are the main producers of lipophilic toxins in temperate coastal waters, including Southern Chile. Strains of the two species differ in their toxin profiles and impacts on shellfish resources. D. acuta is considered the major cause of diarrhetic shellfish poisoning (DSP) outbreaks in Southern Chile, but there is uncertainty about the toxicity of D. acuminata, and little information on microscale oceanographic conditions promoting their blooms. During the austral summer of 2020, intensive sampling was carried out in two northern Patagonian fjords, Puyuhuapi (PUY) and Pitipalena (PIT), sharing D. acuminata dominance and D. acuta near detection levels. Dinophysistoxin 1 (DTX 1) and pectenotoxin 2 (PTX 2) were present in all net tow samples but OA was not detected. Although differing in hydrodynamics and sampling dates, D. acuminata shared behavioural traits in the two fjords: cell maxima (>103 cells L−1) in the interface (S ~ 21) between the estuarine freshwater (EFW)) and saline water (ESW) layers; and phased-cell division (µ = 0.3–0.4 d−1) peaking after dawn, and abundance of ciliate prey. Niche analysis (Outlying Mean Index, OMI) of D. acuta with a high marginality and much lower tolerance than D. acuminata indicated an unfavourable physical environment for D. acuta (bloom failure). Comparison of toxin profiles and Dinophysis niches in three contrasting years in PUY—2020 (D. acuminata bloom), 2018 (exceptional bloom of D. acuta), and 2019 (bloom co-occurrence of the two species)—shed light on the vertical gradients which promote each species. The presence of FW (S < 11) and thermal inversion may be used to provide short-term forecasts of no risk of D. acuta blooms and OA occurrence, but D. acuminata associated with DTX 1 pose a risk of DSP events in North Patagonian fjords.

31

Maturana, Claudia S., Rodrigo A. Moreno, Fabio A. Labra, Claudio A. González-Wevar, Nicolás Rozbaczylo, Franklin D. Carrasco e Elie Poulin. "DNA barcoding of marine polychaetes species of southern Patagonian fjords". Revista de biología marina y oceanografía 46, n. 1 (aprile 2011): 35–42. http://dx.doi.org/10.4067/s0718-19572011000100005.

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32

Godoy, N., A. Canepa, S. Lasternas, E. Mayol, S. Ruíz-Halpern, S. Agustí, J. C. Castilla e C. M. Duarte. "Experimental assessment of the effect of UVB radiation on plankton community metabolism along the Southeastern Pacific off Chile". Biogeosciences 9, n. 4 (2 aprile 2012): 1267–76. http://dx.doi.org/10.5194/bg-9-1267-2012.

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Abstract. The potential effects of UV on community metabolism (NCP, GPP and R) were assessed along the Southeast Pacific off the Chilean coast during the Humbold-2009 cruise (54.80° S–23.85° S) on board R/V Hespérides from 5 to 15 March 2009. Estimates of community metabolism were performed at eight stations, including three stations on Patagonian fjords and five stations on the Humboldt Current System. The effect of UVB radiation on net community production (NCP) was evaluated at the stations in the Humboldt Current system by comparing metabolic rates derived using quartz bottles, largely transparent to UVB, and borosilicate glass, which is opaque to UVB and part of UVA, incubated under the ambient solar radiation. Autotrophic planktonic communities with variable NCP prevailed along the area, with the highest NCP rates (7.1–11.1 mmol O2 m−3 d−1) observed in the Patagonian fjords and the northernmost station. All five experiments showed significantly different NCP rates between communities incubated under the full ambient radiation and those incubated under reduced UVB. One of the experiments showed elevated NCP when the community was exposed to the full solar radiation, while four experiments showed a significantly lower NCP in the presence of UVB. These results suggest that the intense UVB radiation in this area, partly inhibits NCP in the Southwest Pacific off Chile.

33

Ross, L., I. Pérez-Santos, A. Valle-Levinson e W. Schneider. "Semidiurnal internal tides in a Patagonian fjord". Progress in Oceanography 129 (dicembre 2014): 19–34. http://dx.doi.org/10.1016/j.pocean.2014.03.006.

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34

Pinilla, Elías, Manuel I. Castillo, Iván Pérez-Santos, Oliver Venegas e Arnoldo Valle-Levinson. "Water age variability in a Patagonian fjord". Journal of Marine Systems 210 (ottobre 2020): 103376. http://dx.doi.org/10.1016/j.jmarsys.2020.103376.

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35

Capella, Juan J., José Z. Abramson, Yerko A. Vilina e Jorge Gibbons. "Observations of killer whales (Orcinus orca) in the fjords of Chilean Patagonia". Polar Biology 37, n. 10 (3 luglio 2014): 1533–39. http://dx.doi.org/10.1007/s00300-014-1535-5.

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36

González, H. E., L. Castro, G. Daneri, J. L. Iriarte, N. Silva, C. A. Vargas, R. Giesecke e N. Sánchez. "Seasonal plankton variability in Chilean Patagonia fjords: Carbon flow through the pelagic food web of Aysen Fjord and plankton dynamics in the Moraleda Channel basin". Continental Shelf Research 31, n. 3-4 (marzo 2011): 225–43. http://dx.doi.org/10.1016/j.csr.2010.08.010.

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37

Castillo-Hidalgo, Gissella, Mauricio F. Landaeta, Eduardo Anaya-Godínez e Claudia A. Bustos. "Larval fish assemblages from channels and fjords of south Pacific Patagonia: effects of environmental conditions". Revista de Biología Marina y Oceanografía 53 (1 agosto 2018): 39. http://dx.doi.org/10.22370/rbmo.2018.53.0.1253.

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Abstract (sommario):

Chilean Patagonian fjords are characterized by strong stratification and chemical gradients which influence the ichthyoplankton distribution and abundance. Plankton samples were collected through bongo net oblique tows in 40 stations from onboard a bio-oceanographic cruise took place in inner fjords of southern Chile (47° to 51°S). Water column physical data were obtained with a conductivity-temperature-depth profiler (CTD) and turbidity was measured with a portable turbidimeter from 0 to 100 m depth. Stations were distributed by three zones: oceanic, channels and continental waters. A total of 1424 larvae were collected, representing 21 families. Dominant taxa were Maurolicus parvipinnis (31%), Sebastes oculatus (12%), Merluccius australis (11%), Lampanyctodes hectoris (10%), and Bathylagichthys parini (8%). Most of the environmental variability was determined by salinity, mainly in the area where continental waters are discharged. The water column in the oceanic zone presented mixed waters dominated by the myctophid L. hectoris and the sternoptychid M. parvipinnis. No significant effect of turbidity gradients on larval fish assemblages was evident during spring. The channel zone was both more saline, and density stratified with less turbidity, and lower abundance of species. Two ichthyoplanktonic assemblages were evident, one living in oceanic waters, and the other from channels and inner zones.

38

Díaz, Patricio A., e Rosa I. Figueroa. "Toxic Algal Bloom Recurrence in the Era of Global Change: Lessons from the Chilean Patagonian Fjords". Microorganisms 11, n. 8 (25 luglio 2023): 1874. http://dx.doi.org/10.3390/microorganisms11081874.

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Toxic and harmful algal blooms (HABs) are a global problem affecting human health, marine ecosystems, and coastal economies, the latter through their impact on aquaculture, fisheries, and tourism. As our knowledge and the techniques to study HABs advance, so do international monitoring efforts, which have led to a large increase in the total number of reported cases. However, in addition to increased detections, environmental factors associated with global change, mainly high nutrient levels and warming temperatures, are responsible for the increased occurrence, persistence, and geographical expansion of HABs. The Chilean Patagonian fjords provide an “open-air laboratory” for the study of climate change, including its impact on the blooms of several toxic microalgal species, which, in recent years, have undergone increases in their geographical range as well as their virulence and recurrence (the species Alexandrium catenella, Pseudochattonella verruculosa, and Heterosigma akashiwo, and others of the genera Dinophysis and Pseudo-nitzschia). Here, we review the evolution of HABs in the Chilean Patagonian fjords, with a focus on the established connections between key features of HABs (expansion, recurrence, and persistence) and their interaction with current and predicted global climate-change-related factors. We conclude that large-scale climatic anomalies such as the lack of rain and heat waves, events intensified by climate change, promote the massive proliferation of these species by creating ideal conditions for their growth and persistence, as they affect water-column stratification, nutrient inputs, and reproductive rates.

39

Landaeta, M. F., N. Suarez-Donoso, C. A. Bustos e F. Balbontin. "Feeding habits of larval Maurolicus parvipinnis (Pisces: Sternoptychidae) in Patagonian fjords". Journal of Plankton Research 33, n. 12 (15 settembre 2011): 1813–24. http://dx.doi.org/10.1093/plankt/fbr081.

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40

Iriarte, José L., Silvio Pantoja e Giovanni Daneri. "Oceanographic Processes in Chilean Fjords of Patagonia: From small to large-scale studies". Progress in Oceanography 129 (dicembre 2014): 1–7. http://dx.doi.org/10.1016/j.pocean.2014.10.004.

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41

Friedlander, Alan M., Enric Ballesteros, Whitney Goodell, Mathias Hüne, Alex Muñoz, Pelayo Salinas-de-León, Catalina Velasco-Charpentier e Enric Sala. "Marine communities of the newly created Kawésqar National Reserve, Chile: From glaciers to the Pacific Ocean". PLOS ONE 16, n. 4 (14 aprile 2021): e0249413. http://dx.doi.org/10.1371/journal.pone.0249413.

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Abstract (sommario):

The newly created Kawésqar National Park (KNP) and National Reserve (KNR) in southern Chile consists of diverse terrestrial and marine habitats, which includes the southern terminus of the Andes, the Southern Patagonia Ice Fields, sub-Antarctic rainforests, glaciers, fjords, lakes, wetlands, valleys, channels, and islands. The marine environment is influenced by wide ranging hydrological factors such as glacier melt, large terrigenous inputs, high precipitation, strong currents, and open ocean water masses. Owing to the remoteness, rugged terrain, and harsh environmental conditions, little is known about this vast region, particularly the marine realm. To this end, we conducted an integrated ecological assessment using SCUBA and remote cameras down to 600 m to examine this unique and largely unexplored ecosystem. Kelp forests (primarily Macrocystis pyrifera) dominate the nearshore ecosystem and provide habitat for myriad benthic organisms. In the fjords, salinity was low and both turbidity and nutrients from terrigenous sources were high, with benthic communities dominated by active suspension feeders (e.g., Bivalvia, Ascidiacea, and Bryozoa). Areas closer to the Pacific Ocean showed more oceanic conditions with higher salinity and lower turbidity, with benthic communities experiencing more open benthic physical space in which predators (e.g., Malacostraca and Asteroidea) and herbivorous browsers (e.g., Echinoidea and Gastropoda) were more conspicuous components of the community compared to the inner fjords. Hagfish (Myxine sp.) was the most abundant and frequently occurring fish taxa observed on deep-sea cameras (80% of deployments), along with several taxa of sharks (e.g., Squaliformes, Etmopteridae, Somniosidae, Scyliorhinidae), which collectively were also observed on 80% of deep-sea camera deployments. The kelp forests, deep fjords, and other nearshore habitats of the KNR represent a unique ecosystem with minimal human impacts at present. The KNR is part of the ancestral territory of the indigenous Kawésqar people and their traditional knowledge, including the importance of the land-sea connection in structuring the marine communities of this region, is strongly supported by our scientific findings.

42

Rodrigo, Cristián, Daniel López, Erick Cifuentes e Francisco Fernandoy. "Primeras mediciones de isótopos estables de agua y su comportamiento en fiordos de los Campos de Hielo Patagónico Sur, Chile". Revista de Biología Marina y Oceanografía 56, n. 3 (26 aprile 2022): 221–25. http://dx.doi.org/10.22370/rbmo.2021.56.3.3183.

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Stable isotope measurements of seawater from fjords in the Southern Patagonian Icefields area are presented for the first time. Stable water isotope variability was associated with physiographic and oceanographic factors. Isotope depletion and lower salinity were observed at lower depths, which is consistent with shallow estuarine waters. At greater depths, the characteristics of the modified Subantarctic water mass are inferred, and the glacier proximity and temperature do not show a clear relationship with the isotopic contents. These results could be a robust basis for a possible new proxy associated with changes in water masses, freshwater mixing, and paleoclimatic studies.

43

Rodrigo, Cristián, Daniel López, Erick Cifuentes e Francisco Fernandoy. "Primeras mediciones de isótopos estables de agua y su comportamiento en fiordos de los Campos de Hielo Patagónico Sur, Chile". Revista de Biología Marina y Oceanografía 56, n. 3 (26 aprile 2022): 221–25. http://dx.doi.org/10.22370/rbmo.2021.56.3.3183.

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Abstract (sommario):

Stable isotope measurements of seawater from fjords in the Southern Patagonian Icefields area are presented for the first time. Stable water isotope variability was associated with physiographic and oceanographic factors. Isotope depletion and lower salinity were observed at lower depths, which is consistent with shallow estuarine waters. At greater depths, the characteristics of the modified Subantarctic water mass are inferred, and the glacier proximity and temperature do not show a clear relationship with the isotopic contents. These results could be a robust basis for a possible new proxy associated with changes in water masses, freshwater mixing, and paleoclimatic studies.

44

Hüne, Mathias, Alan M. Friedlander, Enric Ballesteros, Jennifer E. Caselle e Enric Sala. "Assemblage structure and spatial diversity patterns of kelp forest-associated fishes in Southern Patagonia". PLOS ONE 16, n. 9 (20 settembre 2021): e0257662. http://dx.doi.org/10.1371/journal.pone.0257662.

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Knowledge of the ecology of the fish fauna associated with kelp (primarily Macrocystis pyrifera) forests in Southern Patagonia is scarce, especially in how abiotic and biotic variables influence their structure, diversity, and distribution. This information is important for the management and conservation of this unique ecosystem, which has minimal anthropogenic impacts at present. We analyzed data from 122 quantitative underwater transects conducted within kelp forests at 61 stations from Chile’s southern Patagonian fjords to the Cape Horn and Diego Ramirez archipelagos and the southern tip of Argentina, including the Mitre Peninsula and Isla de los Estados. In total, 25 fish species belonging to 13 families were observed. Multivariate analysis indicated that there are significant differences in fish assemblage structure among locations and wave exposures, which was driven primarily by Patagonotothen sima and Paranotothenia magellanica, which occurred on exposed and semi-exposed stations. P. cornucola was mainly distributed across sheltered stations of the Kawésqar National Park. Temperature, salinity, depth, and kelp density influenced fish assemblage structure, with the highest diversity in areas with the lowest temperature and greater depth at Isla de los Estados. In contrast, species richness, diversity, abundance, and biomass were all lower in areas with high density of the understory kelp Lessonia spp., which might be driven by the absence of P. tessellata, P. squamiceps and P. cornucola, the most important species in terms of occurrence, abundance, and biomass. Our study provides the first broad-scale description of the fish assemblages associated with kelp forests along the southern cone of South America based on non-invasive visual transects, improving our knowledge of the distribution of fish assemblages across several environmental conditions in this vast and little-studied area.

45

Seguel, Miriam, Carlos Molinet, Manuel Díaz, Gonzalo Álvarez, Carlos García, Andrés Marín, María Olga Millanao e Patricio A. Díaz. "Paralytic Shellfish Toxins in the Gastropod Concholepas concholepas: Variability, Toxin Profiles and Mechanisms for Toxicity Reduction". Marine Drugs 21, n. 1 (6 gennaio 2023): 44. http://dx.doi.org/10.3390/md21010044.

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Harmful algal blooms of toxin-producing microalgae are recurrent in southern Chile. Paralytic shellfish poisoning (PSP) outbreaks pose the main threat to public health and the fishing industry in the Patagonian fjords. This study aims to increase understanding of the individual and spatial variability of PSP toxicity in the foot of Concholepas concholepas, Chile’s most valuable commercial benthic invertebrate species, extracted from the Guaitecas Archipelago in Chilean Patagonia. The objective is to determine the effect of pigment removal and freezing during the detoxification process. A total of 150 specimens (≥90 mm length) were collected from this area. The live specimens were transferred to a processing plant, where they were measured and gutted, the foot was divided into two equal parts, and pigment was manually removed from one of these parts. The PSP toxicity of each foot (edible tissue) was determined by mouse bioassay (MBA) and high-performance liquid chromatography with fluorescence detection and postcolumn oxidation (HPLC-FLD PCOX). The individual toxicity per loco, as the species is known locally, varied from <30 to 146 μg STX diHCL eq 100 g−1 (CV = 43.83%) and from 5.96 to 216.3 μg STX diHCL eq 100 g−1 (CV = 34.63%), using MBA and HPLC, respectively. A generalized linear model showed a negative relation between individual weight and toxicity. The toxicological profile showed a dominance of STX (>95%), neoSTX and GTX2. The removal of pigment produced a reduction in PSP toxicity of up to 90% and could represent a good detoxification tool moving forward. The freezing process in the muscle with pigment did not produce a clear pattern. There is a significant reduction (p < 0.05) of PSP toxicity via PCOX but not MBA. Furthermore, the study discusses possible management and commercialization implications of the findings regarding small-scale fisheries.

46

Rodríguez-Benito, Cristina, Isabel Caballero, Karen Nieto e Gabriel Navarro. "Observation of Maritime Traffic Interruption in Patagonia during the COVID-19 Lockdown Using Copernicus Sentinel-1 Data and Google Earth Engine". Remote Sensing 13, n. 6 (16 marzo 2021): 1119. http://dx.doi.org/10.3390/rs13061119.

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Human mobilization during the COVID-19 lockdown has been reduced in many areas of the world. Maritime navigation has been affected in strategic connections between some regions in Patagonia, at the southern end of South America. The purpose of this research is to describe this interruption of navigation using satellite synthetic aperture radar data. For this goal, three locations are observed using geoinformatic techniques and high-resolution satellite data from the Sentinel-1 satellites of the European Commission’s Copernicus programme. The spatial information is analyzed using the Google Earth Engine (GEE) platform as a global geographical information system and the EO Browser tool, integrated with several satellite data. The results demonstrate that the total maritime traffic activity in the three geographical hotspots selected along western Patagonia, the Chacao Channel, crossing of the Reloncavi Fjord and the Strait of Magellan was totally interrupted during April–May 2020. This fact has relevant repercussions for the population living in isolated areas, such as many places in Patagonia, including Tierra del Fuego. The study also demonstrates the relevance of satellite radar observations in coastal areas with severe cloud cover, such as the one evaluated here.

47

Palma, Sergio, María Cristina Retamal, Nelson Silva e Antonio Canepa. "Siphonophores in fjords and channels in southern Patagonia: biodiversity, spatial distribution and environmental association". Journal of the Marine Biological Association of the United Kingdom 98, n. 2 (20 ottobre 2016): 245–59. http://dx.doi.org/10.1017/s0025315416001302.

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This study characterizes the abundance and spatial distribution of siphonophores between the Trinidad Channel (50°06′S) and the Strait of Magellan (52°45′S) in southern Chile, during October–November 2009. Ten species were identified, of which Agalma elegans, Rosacea plicata and Sphaeronectes fragilis are new records for this region. Dominant species showed similar dominance values e.g. Lensia conoidea (26.3%), Dimophyes arctica (24.6%), Lensia meteori (22.2%) and Muggiaea atlantica (20.7%). Eudoxids of L. conoidea and D. arctica represented 97.3% of all eudoxids collected and they were mainly collected in estuarine waters. The highest densities were found in estuarine waters (high vertical stratification and low temperature, salinity and dissolved oxygen values). On the other hand, the lowest densities were found in coastal areas influenced by permanent influx of Sub-Antarctic waters from the Pacific (greater instability and vertical mixing, higher temperatures, salinity and dissolved oxygen values). Temperature and dissolved oxygen were the most important environmental variables. In general, all the dominant species showed a positive association with temperature and a negative association with dissolved oxygen (with the exception of L. meteori). The vertical distribution showed that M. atlantica was mainly distributed in the first 50 m, in association with estuarine waters, while L. conoidea, L. meteori and D. arctica were mainly found in the deeper layer (50–200 m) and in association with modified Sub-Antarctic waters. The comparison of the results obtained in the springs of 1996 and 2009 showed a significant increase in abundance.

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GALEA, HORIA R., GÜNTER FÖRSTERRA e VERENA HÄUSSERMANN. "Additions to the hydroids (Cnidaria: Hydrozoa) from the fjords region of southern Chile". Zootaxa 1650, n. 1 (30 novembre 2007): 55–68. http://dx.doi.org/10.11646/zootaxa.1650.1.4.

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This report considers five species of hydroids collected during a scientific expedition to the Northern Patagonian Zone of Chile in March 2007. Two poorly known species, Halecium fraseri Ralph, 1958 (Haleciidae) and Thuiaria polycarpa Kirchenpauer, 1884 (Sertulariidae), are redescribed from new, fertile material. The genus Parathuiaria Leloup, 1974 is assigned to the synonymy of Thuiaria Fleming, 1828, and notes are provided on the taxonomy of its type species, T. polycarpa. Three other hydroid species, Halecium tenellum Hincks, 1861 (Haleciidae), Amphisbetia operculata (Linnaeus, 1758) (Sertulariidae), and an athecate hydroid tentatively assigned to the genus Turritopsis McCrady, 1857 (Oceaniidae), are mentioned and accompanied by figures and brief remarks.

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Briceño, Cristóbal, Leslie A. Knapp, Alejandra Silva, José Paredes, Iván Avendaño, Aliro Vargas, Juan Sotomayor e Alejandro R. Vila. "Detecting an increase in an Endangered huemul Hippocamelus bisulcus population following removal of cattle and cessation of poaching in coastal Patagonia, Chile". Oryx 47, n. 2 (aprile 2013): 273–79. http://dx.doi.org/10.1017/s0030605312000014.

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AbstractThe conservation of threatened species poses many challenges but through cooperation and pooling of resources, individuals and organizations can work together to achieve better results. Here we describe our experience, working through a governmental and private alliance, studying one of the most threatened mammals in the Southern Cone. The huemul deer Hippocamelus bisulcus, one of two members of the Hippocamelus genus of South America, is endemic to Argentina and Chile and currently inhabits only a small fraction of its former range. Little is known about the huemul because it generally lives in remote areas with a harsh climate and rugged terrain. Using drive counts and fixed width transects over 5 consecutive years (2004–2008) we estimated density and abundance, and examined population changes and social structure, in three coastal huemul populations in the area of the Témpanos and Bernardo fjords of Bernardo O'Higgins National Park, Chile. Our results suggest that synergistic conservation actions, such as cattle removal and poaching control, can lead to the recovery of threatened huemul. The baseline information obtained from our surveys and the lessons learned through this governmental and private alliance will be useful for future monitoring of the huemul in the Patagonian fjords of Chile.

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Sepúlveda, Sergio A., Alejandra Serey, Marisol Lara, Andrés Pavez e Sofía Rebolledo. "Landslides induced by the April 2007 Aysén Fjord earthquake, Chilean Patagonia". Landslides 7, n. 4 (13 marzo 2010): 483–92. http://dx.doi.org/10.1007/s10346-010-0203-2.

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Articoli di riviste sul tema "Fjords de Patagonie"

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