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| Caniupan, Magaly; Lamy, Frank; Lange, Carina B.; Kaiser, Jerome; Kilian, Rolf; Arz, Helge W.; Leon, Tania; Mollenhauer, Gesine; Sandoval, Susana; De Pol-holz, Ricardo; Pantoja, Silvio; Wellner, Julia; Tiedemann, Ralf. |
| Here we provide three new Holocene (11-0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50-53 degrees S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs except for the past similar to 0.6 cal ka BP. However, they do not exhibit an early Holocene temperature optimum as registered further north off Chile and in Antarctica. This may have resulted from a combination of factors including decreased inflow of warmer open marine waters due to lower sea-level stands, enhanced advection of colder and fresher inner fjord waters, and stronger westerly winds. During... |
| Tipo: Text |
Palavras-chave: Holocene; Alkenones; Sea-surface temperature; Fjords; Chile. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00290/40088/39292.pdf |
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| Rebolledo, Lorena; Gonzalez, Humberto E.; Munoz, Praxedes; Iriarte, Jose L.; Lange, Carina B.; Pantoja, Silvio; Salamanca, Marco. |
| We evaluated changes in siliceous export production and the source of organic matter preserved in sediment core MD07-3109H recovered from the Gulf of Ancud, Chiloe Inner Sea (42 degrees S, 72 degrees W, water column depth: 328 m), southern Chile. We analyzed the abundance of siliceous microfossils (diatoms, silicoflagellates, sponge spicules, Chrysophyte cysts, phytoliths), geochemical proxies (weight percent silicon %Si(OPAL), organic carbon, total nitrogen. C/N molar), and sediment stable isotopes (delta(13)C(org), delta(15)N). Chronology based on (210)Pb and (14)C provided an accumulated age of 144 years at the base of the core. Sediments of core MD07-3109H are predominantly marine in origin, averaging delta(13)C(org)=-20.75 parts per thousand+0.82,... |
| Tipo: Text |
Palavras-chave: Productivity; Siliceous microfossil; Geochemical proxies; Sediments; Gulf of Ancud; Chile. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00214/32520/30999.pdf |
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| Aracena, Claudia; Kilian, Rolf; Lange, Carina B.; Bertrand, Sebastien; Lamy, Frank; Arz, Helge W.; De Pol-holz, Ricardo; Baeza, Oscar; Pantoja, Silvio; Kissel, Catherine. |
| One of the most important factors controlling fjord primary production in southernmost Patagonia is the variability in the thermohaline structure of the water column. In the present-day environment, thermal stratification is mostly related to freshwater input and in particular, the seasonal melting of glaciers. Here we assess whether this relation between fjord productivity and freshwater input holds true for the Holocene, using a sediment record from the central basin of the Strait of Magellan (core MD07-3132, 53°44.17′S; 70°19.03′W, 301 m). Our approach relies on a proxy-based reconstruction of fjord sea surface temperature (alkenone SST), paleosalinity, freshwater input, and paleoproductivity. The results indicate that, during the early Holocene, the... |
| Tipo: Text |
Palavras-chave: Strait of Magellan; Holocene; Paleoproductivity; Thermohaline conditions. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40518/39325.pdf |
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| Bertrand, Sebastien; Hughen, Konrad A.; Sepulveda, Julio; Pantoja, Silvio. |
| The Patagonian fjords have a clear potential to provide high-resolution sedimentary and geochemical records of past climate and environmental change in the Southern Andes. To improve our ability to interpret these proxy records, we investigated the processes that control fjord sediment inorganic geochemistry through a geochemical, mineralogical and sedimentological analysis of surface sediment samples from the fjords of Northern Chilean Patagonia. A simple Terrestrial Index based on measurements of salinity and Fraction of Terrestrial Carbon was used to estimate the terrestrial input/river discharge at each site. Our results demonstrate that, under the cold climate conditions of Patagonia, chemical weathering is weak and the inorganic geochemical... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00092/20299/17933.pdf |
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| Aracena, Claudia; Lange, Carina B.; Iriarte, Jose Luis; Rebolledo, Lorena; Pantoja, Silvio. |
| The Chilean Patagonian fjords region (41-56 degrees S) is characterized by highly complex geomorphology and hydrographic conditions, and strong seasonal and latitudinal patterns in precipitation, freshwater discharge, glacier coverage, and light regime; all of these directly affect biological production in the water column. In this study, we compiled published and new information on water column properties (primary production, nutrients) and surface sediment characteristics (biogenic opal, organic carbon, molar C/N, bulk sedimentary delta(13)C(org)) from the Chilean Patagonian fjords between 41 degrees S and 55 degrees S, describing herein the latitudinal pattern of water column productivity and its imprint in the underlying sediments. Based on information... |
| Tipo: Text |
Palavras-chave: Biogenic opal; Organic carbon; Stable carbon isotopes; Primary production; Fjords; Patagonia. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00214/32519/30998.pdf |
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| Harada, Naomi; Ninnemann, Ulysses; Lange, Carina B.; Marchant, Margarita E.; Sato, Miyako; Ahagon, Naokazu; Pantoja, Silvio. |
| We show environmental and nitrogen cycle changes between 13 and 2.5 kyr BP (from the latest deglaciation to the Holocene) based on biogeochemical records in a sediment core from the Pacific entrance of the Strait of Magellan. Organic carbon, total nitrogen, and C-37 alkenone contents were low during 13-9 kyr BP but increased rapidly at 8 kyr BP. The relative contribution of tetra-unsaturated C-37 alkenone, used as a salinity proxy, suggests low salinity during 13-9 kyr BP changing to high salinity at 8 kyr BP. Planktic foraminifer data showed that Globigerina bulloides was more abundant during the deglacial-early Holocene than in the mid-late Holocene, whereas abundances of Neogloboquadrina pachyderma showed the opposite pattern. This evidence plus... |
| Tipo: Text |
Palavras-chave: Biogenic components; Delta C-13; Delta N-15; Planktic foraminifera; Alkenone; Sea surface temperature; Southern Patagonia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37548/36825.pdf |
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