DANUBE RIVER SULINA BRANCH

(1)

ÇORUH & ACHARISTSGALI RIVER ÇORUH & ACHARISTSGALI RIVER

KERCH STRAIT/KUBAN & DON RIVER KERCH STRAIT/KUBAN & DON RIVER DANUBE RIVER SULINA BRANCH

DANUBE RIVER SULINA BRANCH

DANUBE RIVER ST. GHEORGHE BRANCH DANUBE RIVER ST. GHEORGHE BRANCH

GÜLÜÇ & ÇATALAĞI RIVER GÜLÜÇ & ÇATALAĞI RIVER DNIESTER RIVER

DNIESTER RIVER DISCUSSION & CONCLUSION

PROXY DATA

• n-alkanes show typical odd-over-even- predominance (OEP)

• average chain length of the n-alkanes indica- tes terrigenous C ₃ plant origin for all samples

• δ ¹³ C value of the n-C ₂₉₊₃₁ alkanes indicate C ₃ plant origin of leaf waxes for core GeoB11985

• BIT Index values decrease with increasing distance from land

• C/N ratios vary between 7 and 10: generally high terrigenous input (defined by less molecu- lar nitrogen)

• CPI values are higher in Western Black Sea transects: more phytoplankton contribution or (oil-seepage) contamination in the Eastern Black Sea?

MOLECULAR AGE RELATIONSHIPS

• long-chain n-fatty acids show increasing ages with increasing chain-length: higher re- sistance to degradation?

• long-chain n-alkanes are older than long- chain n-fatty acids

• good age agreement between n-C

₂₈₊₃₀

fatty acid and bulk organic carbon (TOC)

• TOC ages are decreasing with increasing dis- tance from land

TIMESCALES OF TERRIGENOUS ORGANIC MATTER TRANSPORT

• pre-aging on land reflected by the old TOC and biomarker ¹⁴ C ages

• different residence times/reservoir ages for the different hinterlands: Danube River input oldest - highest soil reservoir age? Dniester River input youngest

this study is still in progress...please ask!

ACKNOWLEDGEMENTS

This study was funded by the Helmholtz-University Young Investigators Group „Application of molecular ¹⁴C analysis for the study of sedimentation processes and carbon cycling in marine sediments“. Additional support was given by GLOMAR Bremen International Gra- duate School for Marine Sciences.

TERRIGENOUS ORGANIC MATTER INPUT TO THE BLACK SEA ORIGINATING FROM DIFFERENT HINTERLAND REGIMES

Stephanie KUSCH ^* , Janet RETHEMEYER, Gesine MOLLENHAUER

*Stephanie.Kusch@awi.de

Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany Faculty of Geosciences, University of Bremen, Klagenfurter Str., 28359 Bremen, Germany

INTRODUCTION

We present geochemical proxy data, bulk radiocarbon (

¹⁴

C) ages and compound-specific

¹⁴

C ages of terrige-

nous biomarkers from core-top samples collected along sample transects and from core locations in front of different river mouths around the Black Sea. The sample locations derive terrigenous input from different climatic hinterlands (Figure 1).

STUDY AREA

The Black Sea receives an annual river runoff of 350km³/a. This fluviatile runoff is mainly discharged by the rivers of the north-western coastline (255.4km³/a) which in total account for 73.4% of the riverine freshwater input.

Especially the Danube river, the main tributary, draining 200km³/a transports enormous amounts of terrigenous orga- nic matter to the Black Sea. The Dnies- ter river discharges 9.1km³/a and the Azov Sea discharge amounts to 42.9km

³

/a. The Gülüç and Çatalağci River together discharge 1.32km³/a and the Çoruh and Acharistsgali River amount for 8km³/a.

PROXIES

C/N ratio: elemental ratio C

_HCl

/N

_{non HCl}

Branched and Isoprenoid Tetraether Index (BIT Index):

(GDGT

_m/z1050

+GDGT

_m/z1036

+GDGT

_m/z1022

) /(GDGT

_m/z1050

+GDGT

_m/z1036

+GDGT

_m/z1022

+GDGT

_m/z1092

)

Average Chain Length (ACL): Σ(iX

_i

)/ΣX

_i

with X= abundance and i= 25, 27, 29, 31 and 33 carbon atoms for n-alkanes

Carbon Preference Index (CPI): 0.5*[Σ (X

_i

+X

_i+2

+…+X

_n

)/Σ(X

_i-1

+X

_i+1

+…+X

_n-1

)+Σ (X

_i

+X

_i+2

+…+X

_n

)/Σ(X

_i+1

+X

_i+3

+…+X

_n+1

)]

with X= abundance, i= 25 and n= 33 for n- alkanes

METHODS

GC/FID

PCGC/PFC HPLC/MS

The

¹⁴

C concentration of the n-fatty acids is corrected for the addition of one methyl group during PCGC-purification via mass balance equation.

14

P128 P125 P120 P169 P168 P167

sample

0 0.2 0.4 0.6 0.8 1 1.2

fMC

)TOC

pre-bomb ¹⁴C

7621-1

sample

0 2 4 6 8 10 12 14

C/N ratio ^9.13

0 0.5 1

BIT Index

0.04

Figure 3: Average chain length (ACL) and Carbon Preference Index (CPI) for the Danube River Sulina branch transect.

Figure 5: Radiocarbon data (fraction modern carbon fMC) for the Danube River Sulina branch transect.

Figure 7: Average chain length (ACL) and Carbon Preference Index (CPI) for the Danube River St. Gheorghe branch transect.

Figure 9: Radiocarbon data (fraction modern carbon fMC) for the Danube River St.

Gheorghe branch transect.

Figure 15: Bulk and compound-specific δ¹³C and radiocarbon data (fraction modern carbon fMC) for the Gülüç and Çatalaği River core location.

Figure 14: Average chain length (ACL) and Carbon Preference Index (CPI) for the Gülüç and Çatalaği River core location.

Figure 21: Average chain length (ACL) and Carbon Preference Index (CPI) for the Çoruh and Acharistsgali River transect.

Figure 23: Radiocarbon data (fraction modern carbon fMC) for the Çoruh and Acha- ristsgali River transect.

Figure 18: Bulk and compound-specific δ¹³C data for the Kerch Strait transect.

Figure 19: Radiocarbon data (fraction modern carbon fMC) for the Kerch Strait transect.

Figure 12: Bulk and compound-specific δ¹³C and radiocarbon data (fraction modern carbon fMC) for the Dniester River transect.

Figure 11: Average chain length (ACL) and Carbon Preference Index (CPI) for the Dniester River transect.

Figure 2: C/N ratio and BIT Index for the Danube River Sulina branch transect.

Figure 6: C/N ratio and BIT Index for the

Danube River St. Gheorghe branch transect. Figure 20: C/N ratio and BIT Index for the

Çoruh and Acharistsgali River transect.

Figure 16: C/N ratio and BIT Index for the Kerch Strait transect.

Figure 10: C/N ratio and BIT Index for the Dniester River transect (.

Figure 13: C/N ratio and BIT Index for the Gülüç and Çatalaği River core location.

Figure 17: Average chain length (ACL) and Carbon Preference Index (CPI) for the Kerch Strait transect.

Figure 8: Bulk and compound specific δ¹³C data for the Danube River St. Gheorghe branch transect.

Figure 4: Bulk δ¹³C data for the Danube River Sulina branch transect.

Figure 22: Bulk δ¹³C data for the Çoruh and Acharistsgali River transect.

P128 P125 P120 P169 P168 P167

sample

-36 -32 -28 -24 -20

δ13 C [‰]

)TOC

C₃plant leaf waxes

TOC younger TOC younger

TOC younger TOC younger

younger

C₂₄

younger

C₃plant leaf waxes

C₄plant leaf waxes C₄plant

leaf waxes

C₄plant leaf waxes

11985 11986 11983 11984

sample

-36 -32 -28 -24 -20

δ13 C [‰]

)TOC 1C₂₄ fatty acid +C₂₆ fatty acid %C₂₈₊₃₀ fatty acid AC₂₉₊₃₁ alkane P153 P157 P158

sample

0 0.2 0.4 0.6 0.8 1 1.2

fMC

P153 P157 P158 -36

-32 -28 -24 -20

δ13 C [‰]

)TOC

pre-bomb ¹⁴C

14

P128 P125 P120 P169 P168 P167

sample

0 5 10 15 20 25 30

ACL

29.24 29.7 29.52 29.41 29.55 29.06

0 4 8

CPI4.96

3.83

5.87

4.45

7.14

6.26

P177 P111 P110 7612-3 7614-1 7604-1

sample

0 5 10 15 20 25 30

ACL

29.3 29.77 29.79 29.67 29.67 29.16

0 4 8

CPI4.81

3.94 4.14

6.66

4.25

5.22

7621-1

sample

0 5 10 15 20 25 30

ACL

29.89

0 4 8

CPI4.36

11985 11986 11983 11984

sample

0 5 10 15 20 25 30

ACL

29.51 29.36 29.2 29.31

0 4 8

CPI3.79 4.03 3.83 4.54

P153 P157 P158 MC242

sample

0 5 10 15 20 25 30

ACL

29.68 29.54 29.67 29.35

0 4 8

CPI5.31 6

5.33

4.19

P177 P111 P110 7612-3 7614-1 7604-1

sample

-36 -32 -28 -24 -20

δ13 C [‰]

)TOC 1C₂₄ fatty acid %C₂₈ fattyacid

P177 P111 P110 7612-3 7614-1 7604-1

sample

0 0.4 0.8 1.2

0.2 0.6 1

fMC

)TOC 1C₂₄ fatty acid %C₂₈ fatty acid

7621-1

sample

0 0.2 0.4 0.6 0.8 1 1.2

fMC

7621-1 -36

-32 -28 -24 -20

δ13 C [‰]

)TOC 1C₂₄ fatty acid +C₂₆ fatty acid P177 P111 P110 7612-3 7614-1 7604-1

sample

0 2 4 6 8 10 12 14

C/N ratio

9.41 8.84 8.84 9.29

8.07

13.61

0 0.5 1

BIT Index

0.4

0.04 0.07

0.02 0.03 0.04 P128 P125 P120 P169 P168 P167

sample

0 2 4 6 8 10 12 14

C/N ratio

9.12

7.54

8.82

13.22

8.43

4.61

0 0.5 1

BIT Index

0.64

0.12 0.08 0.04 0.13

0.05

P153 P157 P158 MC242

sample

0 2 4 6 8 10 12 14

C/N ratio

8.67

7.75 8.26 8.72

0 0.5 1

BIT Index

0.26

0.12

0.03 0.04

11985 11986 11983 11984

sample

0 2 4 6 8 10 12 14

C/N ratio ^7.82

8.28

9.36

8.31

0 0.5 1

BIT Index

0.06 0.03 0.02 0.03

terrigenous input

terrigeno

us input terrigenous input

terrigenou

s input

11960 11931 11905

sample

-36 -32 -28 -24 -20

δ13 C [‰]

)TOC

11960 11931 11905

sample

0 0.2 0.4 0.6 0.8 1 1.2

fMC

)TOC 11960

11931 11905

sample

0 2 4 6 8 10 12 14

C/N ratio

10.13 9.95 9.61

0 0.5 1

BIT Index

0.04 0.27

0.04

11960 11931 11905

sample

0 5 10 15 20 25 30

ACL

29.45

29.08 29.09

0 4 8

CPI4.16

4.37 4.14

terrige

nous input

pre-bomb ¹⁴C

younger

11985 11986 11983 11984

sample

0 0.2 0.4 0.6 0.8 1 1.2

fMC

)TOC 1C₂₄ fatty acid +C₂₆ fatty acid %C₂₈₊₃₀ fatty acid AC₂₉₊₃₁ alkane

pre-bomb ¹⁴C

TOC more ma

rine contribution

TOC more marine contribution

C₂₈

CC₂₈₊₃₀₂₆ C₂₄

C₂₆ C₂₄

Figure 1: Study area with core locations on transects in front of major rivers draining the Black Sea from different hinterland regimes.

Danube River South Danube River North Dniestr River Don and Kuban River Çoruh and Acharistsgali River Gülüç and Çatalağci River

DANUBE RIVER SULINA BRANCH

ÇORUH & ACHARISTSGALI RIVER ÇORUH & ACHARISTSGALI RIVER

KERCH STRAIT/KUBAN & DON RIVER KERCH STRAIT/KUBAN & DON RIVER DANUBE RIVER SULINA BRANCH