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Biogeochemica l Research At Lake Baikal Beat Müller, Lawrence Och EAWAG Federal Institute of Science and Technology of the Environment, Kastanienbaum, Switzerland Michael Sturm EAWAG Federal Institute of Science and Technology of the Environment, Dübendorf/Switzerland Elena G. Vologina IEC Institute of the Earth‘s Crust, Russ.Acad.Sci., Irkutsk/Russia

Biogeochemical Research At Lake Baikal

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Biogeochemical Research At Lake Baikal. Beat Müller, Lawrence Och EAWAG Federal Institute of Science and Technology of the Environment , Kastanienbaum, Switzerland Michael Sturm EAWAG Federal Institute of Science and Technology of the Environment , D ü bendorf/ Switzerland - PowerPoint PPT Presentation

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Page 1: Biogeochemical Research At Lake Baikal

Biogeochemical ResearchAt Lake Baikal

Beat Müller, Lawrence OchEAWAGFederal Institute of Science and Technology of the Environment, Kastanienbaum, Switzerland

Michael SturmEAWAGFederal Institute of Science and Technology of the Environment, Dübendorf/Switzerland

Elena G. VologinaIECInstitute of the Earth‘s Crust, Russ.Acad.Sci., Irkutsk/Russia

Page 2: Biogeochemical Research At Lake Baikal

Focus of Scientific Interest

Element budgets and fluxes:

How is the lake influenced by changing loads? How do they affect the ecosystem?Quantify the loads in and out of the lake, and quantify the fluxes between reservoirs

Sediment formation:

Investigation of the biogeochemical processes and rates that determine the formation of the ‘young sediment’ so that the climate signals in the ‘old sediment’ can be interpreted

Page 3: Biogeochemical Research At Lake Baikal

Fluxes between reservoirs and the cycling of elements

Import

Export

Precipitation/DepositionPrimary

ProductionExport from

Epilimnion(New production)

Gross Sedimentation

Net Sedimentation

Mineralization/

Dissolution

Turbulence/

Advection Mineralization

BIOLOGY

GEOLOGY

CHEMISTRY

PHYSICS

Page 4: Biogeochemical Research At Lake Baikal

Sediment traps: • Export from Hypolimnion

• Degrad. in water column

• Gross sedimentation

Sinking

particles

Particle Fluxes: Sedimentation

Page 5: Biogeochemical Research At Lake Baikal

The Large Moorings

Page 6: Biogeochemical Research At Lake Baikal

current meter(30 min. intervals)

Acousticreleaser

T-logger(10 min. intervals)

sequencingtrap(24 cups,2 weeks interval)

integratingtrap

(2 cups)

Mooring Instruments

Page 7: Biogeochemical Research At Lake Baikal

Sediment cores:• Net sedimentation

• Mineralization/Dissolution

sediments

Particle Fluxes: Sedimentation

Page 8: Biogeochemical Research At Lake Baikal
Page 9: Biogeochemical Research At Lake Baikal
Page 10: Biogeochemical Research At Lake Baikal

• Mineralization of organic matter

• Consumption of oxidants• Release of nutrients

water

Processes at the Sediment-Water Interface

sediments

Page 11: Biogeochemical Research At Lake Baikal

O2 concentration

profiles

Mineralization and Dissolution

mm

Page 12: Biogeochemical Research At Lake Baikal

O2 concentration

profiles

Mineralization and Dissolution

mm

In average: 3 mmol O2 m-

2d-1 => 1.1 mio t O2 a-1

i.e. Mineralization of => 880’000 t algae a-1

=> 92 km3 of water (a layer of 3m thickness)

Page 13: Biogeochemical Research At Lake Baikal

Advection:Estimation of annual cold-water intrusions into the deep water of the Lake

Turbulent mixing:Determination of vertical diffusivity with temperature microstructure measurements and inertial diffusivity

eg. Sibio N P

Upwel- ling

Cold water

intrusions

Fluxes in the water column

Page 14: Biogeochemical Research At Lake Baikal

Fluxes in the water column

CDT ProbeTemp.logger

Page 15: Biogeochemical Research At Lake Baikal

kt P yr-1

50 10

P fluxWater column 40 80 P in

Sed. traps

50

25

20P fluxPorewate

rP inSediments

25 difference

30 difference

P inSed. traps

Fluxes of Phosphorus (South Basin)

Page 16: Biogeochemical Research At Lake Baikal

kt P yr-1

50Fluxes of Phosphorus (South Basin)

Page 17: Biogeochemical Research At Lake Baikal

Selenga is the main tributary discharging50 % of the water load75 % of the particle load50 % of terrestrial organic carbon

Monitoring of Tributaries

Reliable monitoring data ofhydrologymajor elements, nutrientssuspended particles

are essential to estimateelement budgetslong term changes

Page 18: Biogeochemical Research At Lake Baikal

Sediment Formation

Sediment formation:

Investigation of the biogeochemical processes and rates that determine the formation of the ‘young sediment’ so that the climate signals in the ‘old sediment’ can be interpreted

Page 19: Biogeochemical Research At Lake Baikal

Formation at the redoxinterface

Upper layer moves up with sedimentation

Lower layer stays in place

Observed in layers of up to 65’000 years

What causes the detachment?

Indicators of changes in the catchment (climate?)

What happens here?

Early diagenetic processes in the sediment

Page 20: Biogeochemical Research At Lake Baikal

Early diagenetic processes in the sediment

Page 21: Biogeochemical Research At Lake Baikal

Early diagenetic processes in the sediment

Page 22: Biogeochemical Research At Lake Baikal

Diagenetic Processes of the Fe/Mn layer

O2

Oxidation of Mn(II) by O2

Reduction of Mn(IV) by Corg, Fe

Diffusion CH4

Methanogenesis

Oxidation by Fe-oxide

Fe(II) reduces Mn-oxide

Diffusion Fe(II)

Diffusion of Mn(II)

Diffusion of Fe(II)

Reduction of Fe(III) by Corg

Page 23: Biogeochemical Research At Lake Baikal

Development of Fe/Mn layers

MnFe

Page 24: Biogeochemical Research At Lake Baikal

Thank you

Page 25: Biogeochemical Research At Lake Baikal
Page 26: Biogeochemical Research At Lake Baikal

SB NB New Production 20.8 14.6 gC m-2 yr-1

Net Sedimentation 2.6 1.5 gC m-2 yr-1

Fluxes of N, P and Sibio were 30% smaller in the NB than in the SB.

Denitrification rates 37 (SB) and 52 (NB) mmol m-2 yr-1. (cf. 57 mmol m-2 yr-1 for oceans (Middleburg et al., 1996))

10.6 and 6.0 mmol P m-2 yr-1 were transferred to the deep water in the SB and NB where 26% and 42% P were retained in the sediments.

Summary Nutrient Budgets

Page 27: Biogeochemical Research At Lake Baikal

Structure of the buried crust: Micro-XRF Profiles

Page 28: Biogeochemical Research At Lake Baikal
Page 29: Biogeochemical Research At Lake Baikal
Page 30: Biogeochemical Research At Lake Baikal

Peeper Plate after Exposition

Page 31: Biogeochemical Research At Lake Baikal
Page 32: Biogeochemical Research At Lake Baikal
Page 33: Biogeochemical Research At Lake Baikal

O2 fluxWater column 20.

820.8

Corg inSed.

traps

14.6

2.611.0

O2 fluxPorewa

ter Corg inSedimens

12.0

difference

6.2 difference7.2

difference

Corg inSed.

traps

gCm-2yr-

1

13.6

sum

Fluxes of Organic Carbon (South Basin)

Page 34: Biogeochemical Research At Lake Baikal

im Sediment-Porenwasser

Rücklösung:0.56 mmol/m2 d

SILIKAT

Jährlicher Eintrag aus dem Einzugsgebiet:

250’000 t Si/Jahr

bei 31’500 km2… 180’000 t Si/Jahr