Decadal to Centennial History of Lena River Discharge to the Arctic Ocean

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Decadal to Centennial History of Lena River
Discharge to the Arctic Ocean

• Principal Investigators
• Eugeny B. Karabanov, Douglas F. Williams
• PhD. Candidates
• Janiel Rivera Pinet
• Straud Armstrong
• Department of Geological Sciences
• University of South Carolina

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Variations of sea-ice flux from the Arctic to the
North Atlantic Ocean are known to cause major
changes in thermohaline circulation. Via this
mechanism, the influx of freshwater from Siberian
rivers plays an important role in ventilation of
the Arctic and North Atlantic Oceans and global
climate processes (SEARCH, 2001). From this point
of view, understanding the history of freshwater
discharge to the Arctic is a critical component
of water exchange between the Arctic, North
Atlantic (PARCS, 1999 ASOF, 2001).
Variations of sea-ice flux from the Arctic to the
North Atlantic Ocean are known to cause major
changes in thermohaline circulation. Via this
mechanism, the influx of freshwater from Siberian
rivers plays an important role in ventilation of
the Arctic and North Atlantic Oceans and global
climate processes (SEARCH, 2001). Understanding
the history of freshwater discharge to the Arctic
is a critical component of water exchange between
the Arctic and North Atlantic (PARCS, 1999 ASOF,
2001).
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Synthesis of river-monitoring data reveals that
the average annual discharge of fresh water from
the six largest Eurasian rivers to the Arctic
Ocean appears to have increased by 7 from 1936
to 1999 (Peterson et al., 2002). These changes in
river discharge are potentially important to NADW
formation and global climate processes.
From Aaagard, Carmack, 1989
From Peterson et al., 2002
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Our goals are

• The Lena River delivers approximately 525 km3
  yr-1 of freshwater. The average sediment supply
  from the Lena to the Laptev Sea is about 21 x106
  tons of suspended material per year and annually
  the Lena River delivers to the Laptev Sea 5.3 t6
  of total organic carbon (4.5 t6 dissolved and 0.8
  t6 particulate organic carbon).

• to recover high-resolution records of
  freshwater discharge variability and terrestrial
  organic carbon flux to the Arctic Ocean via the
  Lena River for the last 50-150 years
• to extend this record into the Late Holocene (
  the last 2,000 years)

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Research Objectives

• determine present-day fluxes of
  freshwater-sediments-organic carbon to the Laptev
  Sea
• parameterize historical records of Lena River
  discharge with sedimentary records
• obtain decadal to centennial scale resolution

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About the Study Area
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First Year Plan on Lena Rivercollect water and
sediment samples, major elements, nutrients and
organic components of Lena River system.

• Major ions, nutrients, dissolved and particulate
  organic carbon
• C, N stable isotopes
• Sediment and suspended matter samples for rare
  and heavy metals
• Sediment and suspended matter samples for
  radionuclides
• Samples for present day pollen rain

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First year plan on Lena River delta - study of
modern processes and proxies of the Lena River
water-sediment-carbon discharge- collect
sediment cores from peat deposits, river
floodplain, lagoons and shallow bays
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Second and Third Year Plans

• Extend our work on Lena River delta to Laptev Sea
  shelf

Lena Delta
Tiksi
SIBERIA
RUSSIA
Yakutsk
Bathymetric units
Jakobsson, M., et al.