Siliceous productivity changes in Gulf of Ancud sediments (42 degrees S, 72 degrees W), southern Chile, over the last similar to 150 years
| Type | Article | ||||||||
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| Date | 2011-03 | ||||||||
| Language | English | ||||||||
| Author(s) | Rebolledo Lorena1, 2, Gonzalez Humberto E.1, 2, 3, 4, Munoz Praxedes5, 6, Iriarte Jose L.3, 4, 7, Lange Carina B.2, 3, 4, 8, Pantoja Silvio2, 3, 4, 8, Salamanca Marco8 | ||||||||
| Affiliation(s) | 1 : Univ Austral Chile, Fac Ciencias, Inst Biol Marina, Valdivia, Chile. 2 : Univ Concepcion, Ctr Invest Oceanog Pacifico Sur Oriental COPAS, Concepcion, Chile. 3 : Univ Concepcion, Programa COPAS Sur Austral, Concepcion, Chile. 4 : CIEP, Bilbao 449, Coyhaique, Chile. 5 : Univ Catolica Norte, Dept Biol Marina, Fac Ciencias Mar, Larrondo 1281, Coquimbo, Chile. 6 : Univ Catolica Norte, Ctr Estudios Zonas Aridas CEAZA, Larrondo 1281, Coquimbo, Chile. 7 : Univ Austral Chile, Ctr Invest Nutr CIEN, Inst Acuicultura, Puerto Montt, Chile. 8 : Univ Concepcion, Dept Oceanog, Concepcion, Chile. |
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| Source | Continental Shelf Research (0278-4343) (Pergamon-elsevier Science Ltd), 2011-03 , Vol. 31 , N. 3-4 , P. 356-365 | ||||||||
| DOI | 10.1016/j.csr.2010.06.015 | ||||||||
| WOS© Times Cited | 16 | ||||||||
| Keyword(s) | Productivity, Siliceous microfossil, Geochemical proxies, Sediments, Gulf of Ancud, Chile | ||||||||
| Abstract | 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, delta(15)N=8.7 +/- 0.35 parts per thousand, and C/N =8.76 +/- 0.36. Marine diatoms compose 94% of the total assemblage of siliceous microfossils. Our record of productivity based on the mass accumulation rates of organic carbon, total nitrogen, Si(OPAL), and total diatoms showed high values between 1863 and 1869 AD followed by a declining trend until 1921 AD, a transition period from 1921 to 1959 AD with fluctuating values, and a clear decreasing pattern from 1960 AD to the present. This marked reduction in productivity was associated with decreased precipitation and Puelo River streamflow (41 degrees S), as well as a warmer and more stratified water column, especially since the 1980s. | ||||||||
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