1 Introduction ................................................. 1
1.1 Phytoplankton pigments as markers for community
structure and environmental changes ..................... 1
1.2 Phytoplankton and pigments in Lake Baikal ............... 9
1.3 International interest in paleoclimate and
paleolimnologic research in Lake Baikal ................ 14
1.4 Outline of the thesis .................................. 16
2 Materials, methods and site descriptions .................... 19
2.1 Lake Baikal ............................................ 19
2.2 Water samples .......................................... 21
2.2.1 Sample collection ............................... 21
2.2.2 Phytoplankton qualitative and quantitative
determination ................................... 22
2.2.3 HPLC-aided pigment analysis in water samples .... 23
2.2.4 Spectrophotometric data from long-term
monitoring ...................................... 24
2.2.5 Fluorescence measurements ....................... 24
2.3 Sediment traps ......................................... 25
2.3.1 Mooring and sampling ............................ 25
2.3.2 HPLC-aided pigment analysis in sediment trap
materials ....................................... 25
2.3.3 C/N-analysis .................................... 26
2.4 Sediment ............................................... 26
2.4.1 Description of CONTINENT coring sites ........... 26
2.4.2 Short and piston core sampling .................. 28
2.4.3 Pigment and C/N-analyses in sediment samples .... 29
2.4.4 Chronography .................................... 29
2.5 Statistics used ........................................ 31
3 Results ..................................................... 33
3.1 Recent spatial and seasonal phytoplankton and pigment
distribution ........................................... 33
3.1.1 Regional distribution ........................... 33
3.1.2 Vertical distribution ........................... 45
3.1.3 Seasonal dynamics ............................... 53
3.2 Pigment transfer through the water column and
preservation in the surface sediment ................... 59
3.2.1 Transfer fluxes and composition of settling
material (South 2001-2002) ...................... 59
3.2.2 Regional and interannual differences of
pigment sedimentation ........................... 66
3.2.3 Degradation and preservation within the
surface sediment ................................ 70
3.3 High-resolution analysis of fossil phytoplankton
pigments ............................................... 75
3.3.1 Holocene ........................................ 75
3.3.2 Last Interglacial (Kazantsevo) .................. 80
4 Discussion .................................................. 87
4.1 Recent phytoplankton pigments in Lake Baikal as
markers for community structure and environmental
changes ................................................ 87
4.1.1 Regional phytoplankton and pigment
distribution and driving factors ................ 88
4.1.2 Pigments as markers for vertical changes
during stratification and homothermy ............ 92
4.1.3 Seasonal dynamics of phytoplankton and
pigments and driving factors .................... 95
4.1.4 Remote sensing .................................. 97
4.1.5 Does a pigment-based approach accurately
monitor phytoplankton community and
environmental changes in Lake Baikal's
euphoric zone? ................................. 100
4.2 Phytoplankton pigment transfer through the water
column and preservation within the surface sediment ... 101
4.2.1 Fluxes in Lake Baikal compared to marine and
freshwater systems ............................. 101
4.2.2 Degradation processes in the water column of
the South basin ................................ 101
4.2.3 Composition of the settling material in the
South basin .................................... 104
4.2.4 Comparison of the sedimentation and
degradation between South and North ............ 105
4.2.5 Degradation within the surface sediment ........ 107
4.2.6 Do recently buried pigments reflect the
phytoplankton standing crop? ................... 109
4.3 Reconstruction of past phytoplankton variations ....... 1ll
4.3.1 Holocene ....................................... 111
4.3.2 Last Interglacial (Kazantsevo) ................. 115
4.3.3 Do fossil pigments track past phytoplankton
community structure and environmental
changes? ....................................... 120
5 Conclusion ................................................. 121
6 References ................................................. 123
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