Carbon Isotope Composition of Particulate Organic Material in
East Siberian Rivers
V. Rachold and H.-W. Hubberten
Alfred-Wegeller-lllstitutfiir Polar- Ulld Meeresforschullg, Forschullgsstelie Potsdam, Telegrafellberg A43,
D 14473 Potsdam, GermallY
Received 14. February 1997 and accepted in revised form 5 March 1998
Abstract - Stable carbon isotope methods have been applied to study the origin of
particulate organic material (POM) in the Siberian rivers Lena, Ya~'\o and Khatanga, all of
which drain to the Laptev Sea. The carbon isotope composition (8 . C values) of POM in
the studied rivers exhibits a range of -25 to -31 %0 vs. V -POB. The negative correlation
between sediment load and total organic carbon (TOC) concentration of the suspended
particulate material (SPM) can be explained by a two-endmember mixing model for the
PRM, which is also confirmed by the carbon isotope data. A linear correlation between
8 . C values and reciprocal particulate organic carbon (POC) concentrations is observed.
Mixing calculations indicate that the major fraction originates from an isotopically heavier,
detrital endmember, while a smaller amount is formed from an isotopically lighter,
autochthonous phytoplankton endmember. Annual carbon fluxes of the studied rivers are
presented in order to demonstrate the significance of riverine carbon export to the Laptev
Sea.
Introduction
Within the framework of the German-Russian project "The Laptev Sea System" (Kassens and
Karpiy, 1994; Kassens et aI., 1994; Kassens et aI., 1995), our study concentrates on the
material transport of East Siberian rivers discharging into the Laptev Sea. Today, large amounts
of sea ice feeding the Transpolar drift are formed above the wide Laptev Sea shelf (Dethleff et
aI., 1993; Niirnberg et aI., 1994; Eicken et aI., 1996). Material transported by the Siberian
rivers, mainly by the Lena, is to some extent incorporated into sea ice entering the Transpolar
drift and contributes to sedimentation in the central Arctic Ocean and the North Atlantic (Bischof
et aI., 1990; Reimnitz et aI., 1994).
The oceanic carbon budget is strongly influenced by fluvial carbon input (Degens et aI.,
1991). To expand our knowledge of the origin of riverine carbon and its transfer to the oceans,
stable carbon isotope methods have been applied in numerous studies (Fontugne and
Jouanneau, 1987; Cai et aI., 1988; Mariotti et aI., 1991; Quay et aI., 1992; Tan and Edmond,
1993; Thornton and McManus, 1994). However, previous investigations concentrated mainly
on tropical rivers. Existing data on Arctic rivers have been summarized by Telang et al. (1991).
Recent studies reported on the biogeochemistry of the Lena (Cauwet and Sidorov, 1996; Lara et
al. in press). In the present article, we focus on the particulate organic material (POM) transport
of the Lena, Yana, and Khatanga (Figure I). The objectives are to identify the sources of the
POM in the Siberian rivers using carbon isotope ratios and to quantify the POM transport to the
Laptev Sea.
Hydrology and Geology of the Lena, Yana, and Khatanga basins
The following section presents a short overview of the hydrological characteristics of the Lena,
Yana, and Khatanga catchment areas. Detailed information has been presented elsewhere
(Alabyan et aI., 1995; Rachold et aI., 1996). In terms of water discharge, the Lena is the eighth
In: Kassens, H., H.A. Bauch, r. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, J. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin. 1999, 223-238.
East Siberian Rivers
V. Rachold and H.-W. Hubberten
Alfred-Wegeller-lllstitutfiir Polar- Ulld Meeresforschullg, Forschullgsstelie Potsdam, Telegrafellberg A43,
D 14473 Potsdam, GermallY
Received 14. February 1997 and accepted in revised form 5 March 1998
Abstract - Stable carbon isotope methods have been applied to study the origin of
particulate organic material (POM) in the Siberian rivers Lena, Ya~'\o and Khatanga, all of
which drain to the Laptev Sea. The carbon isotope composition (8 . C values) of POM in
the studied rivers exhibits a range of -25 to -31 %0 vs. V -POB. The negative correlation
between sediment load and total organic carbon (TOC) concentration of the suspended
particulate material (SPM) can be explained by a two-endmember mixing model for the
PRM, which is also confirmed by the carbon isotope data. A linear correlation between
8 . C values and reciprocal particulate organic carbon (POC) concentrations is observed.
Mixing calculations indicate that the major fraction originates from an isotopically heavier,
detrital endmember, while a smaller amount is formed from an isotopically lighter,
autochthonous phytoplankton endmember. Annual carbon fluxes of the studied rivers are
presented in order to demonstrate the significance of riverine carbon export to the Laptev
Sea.
Introduction
Within the framework of the German-Russian project "The Laptev Sea System" (Kassens and
Karpiy, 1994; Kassens et aI., 1994; Kassens et aI., 1995), our study concentrates on the
material transport of East Siberian rivers discharging into the Laptev Sea. Today, large amounts
of sea ice feeding the Transpolar drift are formed above the wide Laptev Sea shelf (Dethleff et
aI., 1993; Niirnberg et aI., 1994; Eicken et aI., 1996). Material transported by the Siberian
rivers, mainly by the Lena, is to some extent incorporated into sea ice entering the Transpolar
drift and contributes to sedimentation in the central Arctic Ocean and the North Atlantic (Bischof
et aI., 1990; Reimnitz et aI., 1994).
The oceanic carbon budget is strongly influenced by fluvial carbon input (Degens et aI.,
1991). To expand our knowledge of the origin of riverine carbon and its transfer to the oceans,
stable carbon isotope methods have been applied in numerous studies (Fontugne and
Jouanneau, 1987; Cai et aI., 1988; Mariotti et aI., 1991; Quay et aI., 1992; Tan and Edmond,
1993; Thornton and McManus, 1994). However, previous investigations concentrated mainly
on tropical rivers. Existing data on Arctic rivers have been summarized by Telang et al. (1991).
Recent studies reported on the biogeochemistry of the Lena (Cauwet and Sidorov, 1996; Lara et
al. in press). In the present article, we focus on the particulate organic material (POM) transport
of the Lena, Yana, and Khatanga (Figure I). The objectives are to identify the sources of the
POM in the Siberian rivers using carbon isotope ratios and to quantify the POM transport to the
Laptev Sea.
Hydrology and Geology of the Lena, Yana, and Khatanga basins
The following section presents a short overview of the hydrological characteristics of the Lena,
Yana, and Khatanga catchment areas. Detailed information has been presented elsewhere
(Alabyan et aI., 1995; Rachold et aI., 1996). In terms of water discharge, the Lena is the eighth
In: Kassens, H., H.A. Bauch, r. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, J. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin. 1999, 223-238.