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

Arctic OceanArctic Ocean

Principal Investigators:Eugeny B. Karabanov, Douglas F. Williams

PhD. Candidates:Janiel Rivera PinetStraud Armstrong

Department of Geological SciencesUniversity of South Carolina

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Variations of sea-ice flux from the Arctic to the North Variations of sea-ice flux from the Arctic to the North Atlantic Ocean are known to cause major changes in Atlantic Ocean are known to cause major changes in

thermohaline circulation. Via this mechanism, the influx thermohaline circulation. Via this mechanism, the influx of freshwater from Siberian rivers plays an important role of freshwater from Siberian rivers plays an important role in ventilation of the Arctic and North Atlantic Oceans and in ventilation of the Arctic and North Atlantic Oceans and

global climate processes (SEARCH, 2001). From this global climate processes (SEARCH, 2001). From this point of view, understanding the history of freshwater point of view, understanding the history of freshwater discharge to the Arctic is a critical component of water discharge to the Arctic is a critical component of water exchange between the Arctic, North Atlantic (PARCS, exchange between the Arctic, North Atlantic (PARCS,

1999; ASOF, 2001).1999; ASOF, 2001). Variations of sea-ice flux from the Arctic to the North Atlantic Variations of sea-ice flux from the Arctic to the North Atlantic

Ocean are known to cause major changes in thermohaline Ocean are known to cause major changes in thermohaline circulation. Via this mechanism, the influx of freshwater from circulation. Via this mechanism, the influx of freshwater from

Siberian rivers plays an important role in ventilation of the Siberian rivers plays an important role in ventilation of the Arctic and North Atlantic Oceans and global climate Arctic and North Atlantic Oceans and global climate

processes (SEARCH, 2001). processes (SEARCH, 2001).

Understanding the history of freshwater discharge to the Understanding the history of freshwater discharge to the Arctic is a critical component of water exchange between the Arctic is a critical component of water exchange between the

Arctic and North Atlantic (PARCS, 1999; ASOF, 2001).Arctic and North Atlantic (PARCS, 1999; ASOF, 2001).

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Synthesis of river-monitoring Synthesis of river-monitoring data reveals that the average data reveals that the average

annual discharge of fresh annual discharge of fresh water from the six largest water from the six largest

Eurasian rivers to the Arctic Eurasian rivers to the Arctic Ocean appears to have Ocean appears to have

increased by 7% from 1936 to increased by 7% from 1936 to 1999 1999 (Peterson et al., 2002).(Peterson et al., 2002). These These changes in river discharge changes in river discharge are potentially important to are potentially important to NADW formation and global NADW formation and global

climate processes.climate processes.

From Peterson et al., 2002From Peterson et al., 2002

From Aaagard, Carmack, 1989From Aaagard, Carmack, 1989

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)

Our goalsOur goals are: are:

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

Research ObjectivesResearch Objectives

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Tiks i

G iga nsk

K iren sk

Y s t-K u t

About the Study AreaAbout the Study Area

Tiksi

Gigans k

Kiren sk

Yst-K ut

First Year PlanFirst Year Plan on Lena Riveron Lena River

collect water and sediment samples, major collect water and sediment samples, major elements, nutrients and organic components of elements, nutrients and organic components of

Lena River system.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 planFirst year plan on Lena River delta on Lena River delta

- study of modern processes and - study of modern processes and proxies of the Lena River water-proxies of the Lena River water-

sediment-carbon dischargesediment-carbon discharge

- collect sediment cores from peat - collect sediment cores from peat deposits, river floodplain, lagoons deposits, river floodplain, lagoons

and shallow baysand shallow bays

Second and Third Year PlansSecond and Third Year Plans

Extend our work on Lena River delta to Laptev Sea shelf

Lena Delta

Tiksi

Yakutsk

SIBERIARUSSIA

Jakobsson, M., et al.

Bathymetric units: