Sea ice diatom contributions to Holocene nutrient utilization in East Antarctica
| Type | Article | ||||||||||||
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| Date | 2014-04-22 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Panizzo Virginia1, Crespin Julien1, Crosta Xavier2, Shemesh Aldo1, Masse Guillaume3, 4, 5, Yam Ruth1, Mattielli Nadine6, Cardinal Damien5, 6, 7 | ||||||||||||
| Affiliation(s) | 1 : Weizmann Inst Sci, Dept Earth & Planetary Sci, IL-76100 Rehovot, Israel. 2 : Univ Bordeaux 1, UMR CNRS EPOC 5805, F-33405 Talence, France. 3 : CNRS, UMI TAKUVIK 3376, Quebec City, PQ, Canada. 4 : Univ Laval, Quebec City, PQ, Canada. 5 : Univ Paris 06, UPMC IRD CNRS MNHN, LOCEAN IPSL, Paris, France. 6 : Univ Libre Bruxelles, Dept Earth & Environm Sci, Lab G Time, Brussels, Belgium. 7 : Royal Museum Cent Africa, Sect Mineral & Geochem, Tervuren, Belgium. |
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| Source | Paleoceanography (0883-8305) (Amer Geophysical Union), 2014-04-22 , Vol. 29 , N. 4 , P. 328-342 | ||||||||||||
| DOI | 10.1002/2014PA002609 | ||||||||||||
| WOS© Times Cited | 12 | ||||||||||||
| Keyword(s) | diatoms, silicon isotopes, diatom bound carbon isotopes, seasonal ice zone, Holocene, Southern Ocean | ||||||||||||
| Abstract | Combined high-resolution Holocene δ30Sidiat and δ13Cdiat paleorecords are presented from the Seasonal Ice Zone, East Antarctica. Both data sets reflect periods of increased nutrient utilization by diatoms during the Hypsithermal period (circa 7800 to 3500 calendar years (cal years) B.P.), coincident with a higher abundance of open water diatom species (Fragilariopsis kerguelensis), increased biogenic silica productivity (%BSi), and higher regional summer temperatures. The Neoglacial period (after circa 3500 cal years B.P.) is reflected by an increase in sea ice indicative species (Fragilariopsis curta and Fragilariopsis cylindrus, up to 50%) along with a decrease in %BSi and δ13Cdiat (< −18‰ to −23‰). However, over this period, δ30Sidiat data show an increasing trend, to some of the highest values in the Holocene record (average of +0.43‰). Competing hypotheses are discussed to account for the decoupling trend in utilization proxies including iron fertilization, species-dependent fractionation effects, and diatom habitats. Based on mass balance calculations, we highlight that diatom species derived from the semi-enclosed sea ice environment may have a confounding effect upon δ30Sidowncore compositions of the seasonal sea ice zone. A diatom composition, with approximately 28% of biogenic silica derived from the sea ice environment (diat-SI) can account for the increased average composition of δ30Sidiat during the Neoglacial. These data highlight the significant role sea ice diatoms can play with relation to their export in sediment records, which has implications on productivity reconstructions from the seasonal ice zone. | ||||||||||||
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