Sea-surface temperature and sea ice distribution of the Southern Ocean at the EPILOG Last Glacial Maximum—a circum-Antarctic view based on siliceous microfossil records

Gersonde, Rainer; Crosta, Xavier; Abelmann, Andrea; Armand, Leanne K.

doi:10.1016/j.quascirev.2004.07.015

Cited by 523 publications

(589 citation statements)

References 59 publications

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“…Even if a regionally variable carbon reservoir effect (1300-6000 y) is taken into account, the deglaciation indeed appears to have occurred diachronously. A diachronous timing of the coldest climatic conditions around Antarctica during the last glacial period is also indicated by the timing of maximum cooling and sea-ice expansion in the Southern Ocean, which preceded the global sea-level minimum corresponding to the maximum ice sheet build-up [48]. Diachronous deglaciation is also consistent with recent ice-sheet modelling results, which emphasize the role of physical mechanisms other than global sea-level rise in triggering the retreat of grounded ice [49].…”

Section: Extinction In the Seasupporting

confidence: 80%

“…It is thus likely that the selective pressure of submarine mass wasting had a major physical impact on the slope fauna. Additionally, benthic organisms on the slope would have been stressed by low food availability [36], caused by a drop in phytoplankton productivity in response to almost permanent sea-ice cover around Antarctica during the last glacial period (Box 2, Figure Ib [47,48]). The combination of these factors might have contributed to the present impoverishment in diversity of some shallow-water taxa, such as decapods [23] and bivalves [17,24], in Antarctic waters.…”

Section: Extinction In the Seamentioning

confidence: 99%

“…The blue-shaded area represents the depth interval between the present coastline and the 1000-m contour on the continental slope (taken from [66]), corresponding to those areas that were covered by grounded ice and ice shelves, or affected by intense mass wasting, respectively. The bright green line depicts the maximum summer sea-ice extent during the last glacial period according to [47] and the dark green line the extent according to Gersonde et al [48]. The winter sea-ice limit was located even farther to the north according to both reconstructions [47,48] and is not shown.…”

Section: Extinction In the Seamentioning

confidence: 99%

“…The bright green line depicts the maximum summer sea-ice extent during the last glacial period according to [47] and the dark green line the extent according to Gersonde et al [48]. The winter sea-ice limit was located even farther to the north according to both reconstructions [47,48] and is not shown.…”

Section: Extinction In the Seamentioning

confidence: 99%

See 3 more Smart Citations

On the origin of Antarctic marine benthic community structure

Thatje

Hillenbrand

Larter

2005

Trends in Ecology & Evolution

246

273

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Section: Extinction In the Seasupporting

confidence: 80%

Section: Extinction In the Seamentioning

confidence: 99%

Section: Extinction In the Seamentioning

confidence: 99%

Section: Extinction In the Seamentioning

confidence: 99%

See 2 more Smart Citations

On the origin of Antarctic marine benthic community structure

Thatje

Hillenbrand

Larter

2005

Trends in Ecology & Evolution

246

273

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“…In our study, we use contents of opal and biogenic barium (Ba bio ) and MAR Opal for a semi-quantitative Belkin and Gordon, 1996; thin line), the modern summer sea-ice coverage (light-grey shaded), and the sea-ice edges for modern winter (dashed line), LGM summer (bold line) and LGM winter (dotted line) according to Gersonde et al (2005). The area between the modern summer and winter sea-ice edges delineates the present seasonal ice zone (SIZ) and the area between the modern winter sea-ice edge and the APF delineates the modern permanent open-ocean zone (POOZ).…”

Section: Methodsmentioning

confidence: 99%

Polar stratification: A critical view from the Southern Ocean

Hillenbrand

Cortese

2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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Oceanic stratification represents an effective mechanism to reduce vertical mixing of the water column, thereby locking up carbon dioxide (CO 2 ) in the deep sea and preventing air-sea exchange of CO 2 . It has been proposed that enhanced stratification of the upper water column in polar oceans during late Cenozoic cooling episodes limited the upwelling of CO 2 -rich deep waters and thus CO 2 -release to the atmosphere, resulting in a net global drawdown of atmospheric CO 2 . Increased stratification in the Subarctic Northwest Pacific, during both the onset of Northern Hemisphere glaciation at 2.73 Ma and late Quaternary glacial periods, has been recently linked to enhanced ocean stratification south of the Antarctic Polar Front (APF) in the Pacific and Atlantic sectors of the Southern Ocean. Increased stratification of Southern Ocean surface waters was mainly deduced from a reduction of biological production during these cooling episodes, manifested by the decrease of geochemical proxies for productivity, such as biogenic opal and barium, in the marine sediment records. However, the records chosen from the Southern Ocean do not provide evidence for a more stratified upper water column, rather the observed decrease in biological productivity is likely to have resulted from an expansion of annual sea-ice coverage. The sediment records suggest that south of the APF in the Pacific and Atlantic sectors of the Southern Ocean, extensive sea ice may have contributed to the global CO 2 -drawdown during glacial periods, with hypothetical glacial increase of stratification in today's permanent open-ocean zone merely being an "add on" caused by this expansion.

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New insights into sea ice nitrogen biogeochemical dynamics from the nitrogen isotopes

Fripiat

Sigman

Fawcett

et al. 2014

Global Biogeochemical Cycles

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We report nitrogen (N) isotopic measurements of nitrate, total dissolved nitrogen, and particulate nitrogen from Antarctic pack ice in early and late spring. Salinity-normalized concentrations of total fixed N are approximately twofold higher than in seawater, indicating that sea ice exchanges fixed N with seawater after its formation. The production of low-δ 15 N immobile organic matter by partial nitrate assimilation and the subsequent loss of high-δ 15 N nitrate during brine convection lowers the δ 15 N of total fixed N relative to the winter-supplied nitrate. The effect of incomplete nitrate consumption in sea ice is thus similar to that in the summertime surface ocean, but the degree of nitrate consumption is greater in ice, leading to a higher δ 15 N for organic N (~3.9‰) than in the open Antarctic Zone (~0.6‰). Relative to previous findings of very high-δ 15 N organic matter in sea ice (up to 41‰), this study indicates that it would be difficult for sea ice to explain the high δ 15 N of ice age Antarctic sediments. The partitioning of N isotopes between particulate and dissolved forms of reduced N suggests that primary production evolved from new to regenerated production from early to late spring. Even though nitrate assimilation raises the δ 15 N of nitrate, the δ 15 N of sea ice nitrate is frequently lower than that of seawater, providing direct evidence that the regeneration of reduced N in the ice includes nitrification, with mass and isotopic balances suggesting that nitrification supplies a substantial fraction (up to~70%) of nitrate assimilated within Antarctic spring sea ice.

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Sea-surface temperature and sea ice distribution of the Southern Ocean at the EPILOG Last Glacial Maximum—a circum-Antarctic view based on siliceous microfossil records

Cited by 523 publications

References 59 publications

On the origin of Antarctic marine benthic community structure

On the origin of Antarctic marine benthic community structure

Polar stratification: A critical view from the Southern Ocean

New insights into sea ice nitrogen biogeochemical dynamics from the nitrogen isotopes

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