Quality and Distribution of Frozen Organic Matter (Old, Deep, Fossil Carbon) in Siberian Permafrost
Lutz Schirrmeister (1), Jens Strauss (1), Sebastian Wetterich (1), Guido Grosse (2), and Pier Paul Overduin (1)
(1) Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Dept. of Periglacial Research, Potsdam, Germany (Jens.Strauss@awi.de), (2) Geophysical Institute, Permafrost Laboratory, University of Alaska Fairbanks, Fairbanks, USA
Introduction
ŸSince 1998, northeast Siberian permafrost sequences have been analyzed as frozen paleoenvironmental archives of the last
~200,000 years (joint Russian-German science cooperation “SYSTEM LAPTEV SEA”). Organic matter (OM) properties were used as an important paleo proxy
ŸThis study summarizes regional datasets on the quality and quantity of fossil OM in permafrost sequences of NE Siberia:
à to show the permafrost carbon pool heterogeneity related to paleoenvironmental dynamics, and
à to improved estimations of permafrost organic carbon stocks.
• OM distribution in the upper permafrost zone up to 100 m depth in the Northeastern Siberian Arctic indicates considerable variability of OM between different stratigraphical units, between same stratigraphical units at different study sites, and even within stratigraphic units at the same site.
0 50 100
Absolute ice content
[%]
0 2 4 6 8
Height[ma . s. l . ]
0 2 4 6 8
Height[ma . s. l . ]
6 8 10
Height[ma . s. l . ]
16 18 20 22 24 26 28
Height[ma . s. l . ]
4 6 8 10 12
Height[ma . s. l . ]
0 50 100
Absolute ice content
[%]
0 10 20
TOC [wt%]
0 10 20
TOC [wt%]
0 5 10
TIC [wt%]
0 5 10
TIC [wt%]
0 20 40
C/N
0 20 40
C/N
-32 -28 -24
13C [VPDB, ‰]
-32 -28 -24
13C [VPDB, ‰]
Late Glacial / Early Holocene thermokarst lake deposits Holocene polygonal cover in thermokarst depression
Taberite formed during Weichselian to Holocene transition
Middle Weichselian Ice Comlex deposits
Early Weichselian alluvial deposits
Eemian
thermokarst lake deposits
Taberite formed during Saalian to Eemian transition
Pre-Eemian
alluvial deposits
Late Saalian Ice Complex deposits
1
2 3
4 5
6 7
8 9
11
12 13 10
16 15
18 17
14
19
20 21
22
Study sites
Western Laptev Sea:
(1) Cape Mamontov Klyk Lena Delta:
(2) Turakh Sise Island, (3) Ebe Sise Island (Nagym), (4) Khardang Island, (5) Kurungnakh Sise Island
Central Laptev Sea:
(6) Bykovsky Peninsula, (7) Muostakh Island New Siberian Archipelago:
(8) Stolbovoy Island, (9) Bel’kovsky Island, (10) Kotel’ny Island (Cape Anisii), (11) Kotel’ny Island (Khomurganakh River), (12) Bunge Land (low terrace), (13) Bunge Land (high terrace), (14) Novaya Sibir Island, (15) Maly Lyakhovsky Island
Dmitry Laptev Strait:
(16) Bol’shoy Lyakhovsky Island (Vankina river mouth), (17) Bol’shoy Lyakhovsky Island (Zimov’e river mouth), (18) Cape Svyatoy Nos, (19) Oyogos Yar coast
Indigirka-Kolyma lowland:
(20) Duvanny Yar (Lower Kolyma R. ).
(21) Kytalyk (Berelekh R.), (22) Pokhodsk (Kolyma Delta)
of permafrost archives in NE Siberia with fossil OM data sets
EGU2013-12417
Methods
Ice content – gravimetrically measured
→ Ice-rich (>50 %), ice-bearing (25-50 %), ice-poor (< 25%)
→ Syncryogenic formation, thawing & refreezing (taberite)
→ Total mass balance calculation, bulk density estimation
TC, TN, TOC - CNS analyzer (Elementar Vario EL III)
TOC → Variations in OM accumulation and degradation TOC/TN → Decomposition degree, microbial activities
→ Low ratios: strongly decomposed;
high ratios: less decomposed
TC-TOC→ TIC; inorganic carbon (e.g. fossil shells)
d13C (TOC) - Finnigan DELTA S mass spectrometer
→ OM origin (marine, terrestrial; subaerial/aquatic)
→ Composition of plant material
→ Isotopic fractionation during carbon metabolism
13 13
→ Decomposition degree (low d C less, high d C strong)
44.2 ± 9.0 n = 22 44.4 ± 16.0 n = 67 47.4 ± 14.6 n = 20
40.3 ± 12.8 n = 234 28.8 ± 4.8 n = 4 38.3 ± 12.5 n = 66
22.4 ± 11.3 n = 313 29.0 ± 8.3 n = 37 32.6 ± 8.3 n = 23 58.7 ± 20.1 n = 20 0 20 40 60 80 100
10.9 ± 12.2 n = 50 5.3 ± 4.9 n = 52 5.9 ± 9.0 n = 148
3.7 ± 4.2 n = 359 2.7 ± 1.4 n = 9 2.2 ± 0.9 n = 109
0.4 ± 1.3 n = 426 3.1 ± 4.0 n = 75 1.0 ± 0.7 n = 119 6.2 ± 4.1 n = 14 0.01 0.1 1 10
0.2 ± 0.2 n = 22 0.2 ± 0.3 n = 114 0.6 ± 0.6 n = 37
0.4 ± 0.5 n = 289 0.4 ± 0.1 n = 9 0.4 ± 0.2 n = 94
0.1 ± 0.1 n = 352 0.6 ± 0.9 n = 61 0.3 ± 0.1 n = 15 1,82 ± 3.0 n = 9
0 2 4 6 8
11.8 ± 3.2 n = 50 10.0 ± 5.4 n = 133 14.9 ± 5.8 n = 42
10.6 ± 5.2 n = 311 7.3 ± 3.4 n = 9 9.3.0 ± 2.3 n = 112
8.8 ± 8.8 n = 79 10.2 ± 3.7 n = 37 6.5 ± 5.0 n = 16 14.2 ± 4.8 n = 14
0 10 20 30 40
-27.63 ± 0.87 n = 52 -27.93 ± 1.33 n = 139 -27.98 ± 1.320 n = 49
-26.38 ± 1.26 n = 338 -29.47 ± 1.55 n = 9
-25.58 ± 0.70 n = 111
-25.70 ± 1.31 n = 99 -27.50 ± 0.70 n = 36 -25.05 ± 0.29 n = 18 -27.89 ± 1.03 n = 14 -32 -30 -28 -26 -24 -22
Middle Weichselian Ice Complex Holocene thermo- erosional valley Late Glacial to Holocene thermokarst Holocene cover Taberites
Late Weichselian Ice Complex
Early to Late Weichselian fluvial deposits Eemian thermokarst lake deposits Pre Eemian floodplain Late Saalian ice-rich deposits
absolute
ice content (wt%) TOC (wt%) TIC (wt%) C/N C (‰ vs VPDB)d13
Stratigraphical classification of permafrost deposits by organic matter signatures, Schirrmeister et al. (2011)
min max
median Q1 Q3
Box plot graph displays the minimum, maximum, median, lower quartile and upper quartile
The south coast of Bolshoy Lyakhovsky Island
Lateglacial to Holocene thermokarst basins (lacustrine and polygonal mires)
Middle Weichselian Ice Complex deposits
Eemian ice wedge casts Early Weichselian alluvial deposits
Studied section of different stratigraphical units from Bolshoy Lyakhovsky Island (site 16), Dmitry Laptev Strait
Stratigraphical Units
Ice Content
[wt%] Bulk
Density [g cm-3],
Total organic
carbon [wt%],
Carbon inventory
[kg C m-3] SD Holocene thermo-erosional
valley 44.2 ± 9.0 0.781 5.3 ± 4.9 41.42 40.87
Holocene thermokarst 44.4 ± 16.0 0.775 6.9 ± 9.0 53.51 77.22
Holocene cover 47.4 ± 14.5 0.686 10.9 ± 12.9 74.73 96.26
Taberites 28.8 ± 4.8 1.242 2.7 ± 1.4 33.55 17.82
Late Weichselian
Ice Complex 38.3 ± 12.5 0.958 2.2 ± 0.9 21.08 11.92
Middle Weichselian
Ice Complex 40.5 ± 12.8 0.892 3.7 ± 4.1 33.23 40.07
Early to Middle Weichselian
fluvial deposits 22.4 ± 11.3 1.434 0.5 ± 1.4 7.17 18.72
Eemian lake deposits 29 ± 8.3 1.236 3.2 ± 4.2 39.57 50.10
Pre Eemian floodplain 32.6 ± 8.3 1.129 1.0 ± 0.8 11.29 8.28
Saalian Ice Complex 58.7 ±20.1 0.347 5.3 ± 4.3 18.41 34.93
Carbon inventory estimates
General scheme of the stratigraphical segments of the permafrost zone, and several components of arctic periglacial landscapes
Yedoma
Thermokarst depression
(alas)
Thermo- erosional valley
Distance (m)
SE
Zimov'e River valley
height(ma.s.l.)
IV IV
IIa
4500 5000 5500
4000 3500
3000 2500
2000
1500 6000
500
0 6500
0 5 10 15 20 25 30 35
NW
Thermokarst depression
(alas)
Taberal deposits Saalian ice-rich deposits
Eemian thermokarst deposits
Pre Eemian flood plain deposits Middle Weichselian ice-rich deposits with numerous peat inclusion
Holocene deposits
Ice wedges of different generations Peat in the modern
flood plain Early Weichselian flood plain deposits
Periglacial reworked weathering crust
+ 40
+ 30
+ 20
+ 10
0
- 10
- 20
- 30
- 40
Eemian Interglacial
Saalian glacial Weichselian Glacial
Active layer
Tertiary Talik
Dmitry Laptev Strait Thermokarst
depression
Cretaceous basement rocks Holocene cover
Permafrost table
height[ma.s.l.]
Ice wedges Plant cover
Ice casts
Saalian ice-rich deposits (200 to 150 ka)
Eemian thermokarst deposits (130 to 110 ka)
Early Weichselian (100 to 60 ka) and
pre Eemia (> 130 ka) flood plain deposits
Middle Weichselian ice-rich deposits with numerous peat inclusion
(60 to 25 ka)
Late Weichselian ice-rich deposits (25 to 15 ka)
Lategalcial (15 to 10 ka) and Holocene deposits (< 10 ka)
Talik zone
Unfrozen marine deposits (< 5ka) Unfrozen lake deposits (< 10 ka)
Thermokarst lake
Tertiary sands with coal
Bedrock (granite,limestone, sandstone)
?
? ?
? ?
Talik
?
? ?
?
?
Eemian taberites
Conclusion
ŸCarbon contents, OM qualities and decomposition degrees are highly variable and connected to changing paleoenvironmental conditions
à Interglacial & interstadial periods: High TOC contents, high C/N, low δ13C less-decomposed OM accumulated under wet, anaerobic soil conditions.
à Glacial & stadial periods: Less variable, low TOC, low C/N, high δ13C values stable environments with reduced bioproductivity and stronger OM decomposition under dryer, aerobic soil conditions.
ŸOM release to the ocean, lakes, rivers and the atmosphere due to permafrost degradation (e.g.
thermokarst, thermal erosion, coastal erosion) and microbial decomposition.
ŸThe landscape average is likely about 30 % lower than previously published permafrost carbon inventories
ŸStill large uncertainties in carbon estimations/
calculations.
à Detailed mapping of permafrost deposits especially of Ice Complex (Yedoma-type) and thermokarst deposits (Alas-type), their distribution and thickness are essential for OM pool estimation.
à Measurements and estimations on OM available for decomposition are necessary.
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Reference
Schirrmeister, L., G. Grosse, S. Wetterich, P. P. Overduin, J. Strauss, E. A. G. Schuur, and H.‐
W. Hubberten (2011), Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic, J. Geophys. Res. 116, G00M02, doi:10.1029/2011JG001647
Scheme of stratigraphical units from Bolshoy Lyakhovsky Island (site 17), Dmitry Laptev Strait
