Tracing soil organic matter from source to sink

Jung-Hyun Kim1,*, Claudia Zell1, Patricia Moreira-Turcq2, Marcela Andrea Pérez3, David Hollander4, Dorthe KlitgaardKristensen5, Roselyne Buscail6, Jaap S. Sinninghe Damsté1

1Royal Netherlands Institute for Sea Research (NIOZ), The Netherlands, 2IRD-LMTG-HYBAM, France, 3UFAM, Brazil, 4University of South Florida, USA, 5Norwegian Polar Institute, Norway, 6CEFREM-CNRS UMR 5110, France, y, ,

1. Introduction:The transport of terrestrial organic matter (OM) to coastal sediments representsa significant flux in the global carbon cycle. Although a large range of bulk andmolecular proxies for terrestrial OM is available, quantification of the relativeinputs of terrestrial OM to marine sediments is still difficult. The incompleteunderstanding of the transfer of terrestrial OM from land to the ocean isprobably due to the lack of diagnostic (geochemical) proxies especially for soilOM hi h t f t thi d f th t t l t t i l b b d t R tl

I.

O

OO

O

OH

O

O

OH

O

O

OH

II.

Branched versus Isoprenoid Tetraether

(BIT) index:

*E-mail: Jung-Hyun.Kim@nioz.nl

OM which accounts for two third of the total terrestrial carbon budget. Recently,several developments have however led to new insights into the recognition ofsoil OM in marine environments. The Branched and Isoprenoid Tetraether (BIT)index (Hopmans et al., 2004, Fig. 1) has been introduced as a proxy to trace soilOM input from land to the marine environments (e.g. Walsh et al., 2008; Kim etal., 2009). This index is based on the relative abundance of non-isoprenoidalglycerol dialkyl glycerol tetraethers (GDGTs) versus a structurally relatedisoprenoid GDGT “crenarchaeol”. Branched GDGTs are produced by anaerobicbacteria thriving in soils (Weijers et al., 2006), whereas crenarchaeol isproduced predominantly by marine Crenarchaeota (Sinninghe Damsté et al.,2002). We discuss the use of the BIT index to trace soil OM input in contrastingdepositional settings: the Rhone prodelta (NW Mediterranean), the fjords of

O

OH

O

O

OH

O

O

OH

O

O

O

O

OH

OH

III.

IV.Approaching 0 → marine dominated organic matterApproaching 1 → soil dominated organic matter

[I + II + III]

[I + II + III + IV]

Fig. 1. Glycerol dialkyl glycerol tetraethers (GDGT) structures and the definition of theBIT index. I, II, and III indicate the branched GDGTs and IV is crenarchaeol.p g p ( ), j

Svalbard (Arctic Ocean), and the Amazon shelf and fan (tropical Atlantic).

2. Results:

Amazon shelf & fan (tropical Atlantic):

0.90 (n = 1)0.85 (n = 45)

Têt

0.78 (n = 1)

0.72 (n = 1)

AudeAgly

Gulf of Lions (NW Mediterranean):

Latit

ude

0

10

500

600

700

800

900

1000

Le

vel (

cm)

High water level (June 2005)

Fjords of Svalbard (Arctic Ocean):

LB KLB

MB

TB

B

A

0.8

1.0

(0.96±0.05, n=15)

Fig. 2. We investigated suspended particulate matter (SPM) collectedin the Rhône River and its tributeries (Doubs, Saône, Ain, Isère, andDurance) and other smaller Mediterranean rivers. BIT values of theRhône River are comparable to those of its tributaries. The BIT valueof the Rhône River at Arles (0.9, n=1) is higher than those of smallerMediterranean rivers flowing into the Gulf of Lions.

43 5

44.0

1

44.0

0.4

A Bbranched GDGTs BIT index

Rhône RiverRhône River

Water depth Altitude (m)

Longitude

-80 -70 -60 -50

-10

Fig. 6. Sampling locations of soil (O) and SPM in the red box in theAmazon basin. The SPM samples were collected during the highwater level in June, 2005.

0

100

200

300

400

O N D J F M A M J J A S O N D J

Water Cycle

Wa

ter

L

Amazon River

Fig. 4. (A) Map of the Arctic Ocean. (B) Sampling locations of marinesurface sediment (O), IRD (), soil (), and coal (). LB, KLB, MB,TB, KB, and KV indicate Lilliehöökbreen, Kollerbreen, Mayerbreen,Tinayrebreen, Kongsbreen, and Kongvegen, respectively. The BITindex of Svalbard soils was close to, as is typically found for soils. BITvalues of IRD were much lower while those of marine sediments

12°00'E11°00'E

79°10'N

79°00'N

Kongsfjord

Kross

fjord

Ny-Ålesund

KB

KVCoal

0.0

0.2

0.4

0.6

BIT

inde

x

Soil Coal IRD Marine sediment

nd

(0.44±0.06, n=4)

(0.02±0.02, n=29)

0 0

0.2

0.4

0.6

0.8

1.0

BIT

index 0.97±0.03

(n=21)0.93±0.03

(n=10) 0.84±0.09 (n=15)

79.0

79.2

79.4

Latit

ude

Latit

ude

C:N ratio

-25

-24

-23

-22

4

5

6

7

8

79.0

79.2

79.4

0

20

40

60

80ReteneC

0

40

80

120

160

A

Ny-Ålesund

Ny-Ålesund

Ny-Ålesund

Ny-Ålesund

B

D

D

December, 2003

2.5 3.0 3.5 4.0 4.5 5.0 5.5

42.0

42.5

43.0

43.5

0

5

10

15

2.5 3.0 3.5 4.0 4.5 5.0 5.5

42.0

42.5

43.0

43.5

-0.1

0.1

0.2

0.3

Latit

ude

(N)

Lat

itude

(N

)

0.0

Têt RiverTêt River

Rhône River

2.5 3.0 3.5 4.0 4.5 5.0 5.5

42.0

42.5

43.0

43.5

44.0

0

10

30

50

70

90

100

(%)

C Soil percentage

Têt River

Rhône River

(g

g TO

C-1

)

Fig. 7. The BIT values of soils are close to 1. BIT values of river bedsediments are also high, while those of river SPM are generally lower,varying among different tributaries.

values of IRD were much lower, while those of marine sedimentswere generally low.

n-alkane

13Corg

0.0

Soil River bed sediment June SPM

Rio Negro

Rio SolimõesRio Madeira

Rio Tapajós

Rio Amazonas

Rio Trombetas

Obidos

0.92±0.0 (n=4)

0.90±0.0 (n=3)

0.74±0.01 (n=2)

0.59 (n=1)

0.87 (n=1)

0.81±0.02 (n=4)

6

g g

OC

-1)

g g

OC

-1)

‰V

PD

B)

79.0

79.2

79.4

Latit

ude

E Branched GDGTs

0

1

2

3

4

BIT

LongitudeLongitude

Latit

ude

10.5 11 11.5 12 12.510.5 11 11.5 12 12.5

79.0

79.2

79.4Ancient OMMarine OM

0

20

40

60

80

Ny-Ålesund Ny-Ålesund

BIT index

0

0.1

0.2

0.3

0.4

F

Ny-Ålesund Ny-Ålesund

HG

0

20

40

60

80

4. Future work:We will continue to work on soils and SPM collected in theAmazon watershed and marine surface sediments as well as

Longitude (E) Longitude (E)

Fig. 3. In the Gulf of Lions, BIT values range from 0.01 to 0.85, withhigher values along the coast compared to those offshore. The soilOM contributions to the total organic carbon (TOC), estimated basedon the BIT index, are >10% along the coast, while those from theouter shelf and the continental slope are below 10% (Kim et al.,2010). The spatial distribution patterns of GDGT parameters aresimilar to the MODIS image of the Gulf of Lions showing across andalong-shelf dispersion of the river plumes occurred in December,2003 (Guillén et al., 2006).

Fig. 5. Bulk geochemical parameters suggest a predominant marine

BIT

ind

ex

-54 -52 -50 -48 -46 -44 -42-4

-2

0

2

4

6

Lat

itude

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

g g

OC

-1)(%

)

(%)

Amazon watershed and marine surface sediments as well asSPM sampled in the Amazon shelf and fan. GDGTparameters will be compared with other geochemicalparameters. This will further shed light on the potential of theBIT index for tracing soil OM input from land to the ocean andquantifying its fluxes.

Reference:Hopmans, E.C., J.W.H. Weijers, E. Schefuß, L. Herfort, J.S. Sinninghe Damsté, and S. Schouten, A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoidtetraether lipids. Earth Planet.

Sci. Lett. 224, 107-116, 2004.Kim, J.-H., B. Zarzycka, R. Buscail, F. Peters, J. Bonnin, W. Ludwig, S. Schouten, and J.S. Sinninghe Damsté, Factors controlling the Branched Isoprenoid Tetraether (BIT) Contribution of river-borne soil organic carbon to

the Gulf of Lions (NW Mediterranean). Limnol. Oceanogr.,55, 507–518, 2010.Walsh, E.M., A.E. Ingalls, and R.G. Keil. Sources and transport of terrestrial organic matter in Vancouver Island fjords and the Vancouver-Washington Margin: A multiproxy approach using d13Corg, lignin phenols, and the

ether lipid BIT index. Limnol. Oceanogr. 53, 1054-1063, 2008.Sinninghe Damsté, J.S., E.C. Hopmans, S. Schouten, A.C.T. van Duin, and J.A.J. Geenevasen, Crenarchaeol: the characteristic core glycerol dibiphytanyl glycerol tetraether membrane lipid of cosmopolitan pelagic

crenarchaeota. J. Lipid Res., 43, 1641-1651, 2002.Weijers, J.W.H., S. Schouten, E.C. Hopmans, J.A.J. Geenevasen, O.R.P. David, J.M. Coleman, R.D. Pancost, and J.S. Sinninghe Damsté, Membrane lipids of mesophilic anaerobic bacteria thriving in peats have typical

archaeal traits. Environ. Microbiol., 8, 648-657, 2006.

Fig. 8. The BIT values of marine sediments collected in the Amazonfan in 2010 are generally around 0.1, except for three sites withenhanced values (0.4-0.8). This suggests that deposition orpreservation of soil organic matter are higher at those sites located onthe continental shelf and slope.

Acknowledgement:We thank to J. Ossebaar. M. Kienhuis, and E. Hopmans (NIOZ) for analytical support. Thanks also go to V.Willmott, F. Peterse, N. Koç, other participants, and the crew of the SciencePub International Polar Yearcruises on the R/V Lance from the Norwegian Polar Institute. This study was carried out within the ERCPACEMAKER (Past Continental Climate Change: Temperatures from Marine and Lacustrine Archives) and ERGSOURCE (Tracing Amazon soil organic carbon input from land to the ocean) projects. This work was alsosupported by the CARBAMA (Carbon biogeochemistry and atmospheric exchanges in the Amazon Riversystem), the CHACCRA (Climate and Human induced Alterations in Carbon Cycling at the River-seAconnection), and EXTREMA (Episodes météo-climatiques extrêmes et redistribution des massessédimentaires et des polluants associés au sein d'un système côtier) projects funded by the French NationalResearch Agency.

contribution to sedimentary OM. The BIT index indicates that soil OMcontribution to the marine sediments is minor. However, theparameters of retene, n-alkanes, and the depleted bulk radiocarboncontent (14C value) suggest that ancient OM of both coal-derivedand mature IRD-derived OM is being buried in the Kongsfjord-Krossfjord system of Svalbard in the high Arctic.

Longitude