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SUMMARY:Silicon cycling and opal production in the Atlantic: lessons from 
 the last deglaciation - Kate Hendry\, University of Bristol
DTSTART:20161013T163000Z
DTEND:20161013T173000Z
UID:TALK67659@talks.cam.ac.uk
CONTACT:Dr Rachael Rhodes
DESCRIPTION:Major shifts in ocean circulation are thought to be responsibl
 e for abrupt shifts in temperature and atmospheric CO2 as the Earth warmed
  up after the last ice age\, linked to changes in latitudinal heat transpo
 rt and deep ocean carbon storage. There is also widespread evidence for sh
 ifts in biological production during these times of deglacial CO2 rise\, i
 ncluding enhanced growth of silica-producing algae (diatoms) in regions su
 ch as the equatorial Atlantic. In this talk\, I’ll show how we can use m
 arine sediment geochemical archives to demonstrate that the supply of diss
 olved silicon – a key nutrient for diatoms - was enhanced in the NE Atla
 ntic during the abrupt climate events of the deglaciation. However\, despi
 te an enriched supply of this critical nutrient at depth\, diatoms could o
 nly proliferate during abrupt climate shifts in regions of the NE Atlantic
  where the deep supply of dissolved silicon could reach the surface. These
  regions were influenced by enhanced regional wind-driven upwelling and we
 akened stratification due to circulation changes during phases of weakened
  Atlantic meridional overturning. Globally near-synchronous pulses of diat
 om production and enhanced subsurface concentrations of dissolved silicon 
 suggest that widespread deglacial surface-driven breakdown of stratificati
 on\, linked to changes in atmospheric circulation\, had major consequences
  for biological productivity and carbon cycling across the North Atlantic.
LOCATION:Latimer Room (Old Court)\, Clare College\, Trinity Lane
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