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T9
Diatom response to recent pollution and environmental change at
Lake Baikal, Siberia
S. Roberts 1 *, S. McGowan 1 , G.E.A. Swann 1 , A.W. Mackay 2 , V.N. Panizzo 1
1 School of Geography, University of Nottingham, Nottingham;
2 ECRC, Department of Geography, UCL, London
This research project aims to investigate the impact of recent anthropogenic activity, and
natural climate variability over the past 1000 years on Lake Baikal. Situated within a rift
zone in southeastern Siberia, Lake Baikal is the world’s oldest, deepest and most
voluminous lake, leading to high levels of endemicity (Timoshkin, 2007). This UNESCO
site has undergone substantial catchment changes since the 1950s as a result of
increased development, catchment logging and industrialisation, increasing the nutrient
loading into the photic zone (Ciesielki et al., 2006). Interlinked with this, declining ice-cover
thickness and duration along with increased nutrient enrichment from regional permafrost
thaw and fluvial input are also suggested to have impacted the aquatic ecosystem
(Hampton et al., 2008; Todd and Mackay, 2003).
We studied diatoms from sediment cores in the north, south and central basins of the lake.
Diatoms contribute to over half of the primary productivity within Lake Baikal and are
comprised of many endemic species (e.g. Aulacoseira baicalensis and Cyclotella minuta).
We hypothesised that within areas of localised eutrophication the abundances of
cosmopolitan diatom species such as Synedra acus v. radians and Synedra acus v. acus
will increase due to higher nutrient availability (nitrogen, phosphorus and silicon). Previous
research shows evidence of diatom assemblage changes within shallow-water regions of
the south basin from 1960 AD onwards in regions close to major fluvial inputs and
factories (Mackay et al, 1998). However, the impact of recent nutrient enrichment over the
last 15-20 years from increased catchment activity remains unknown. Results from diatom
taxonomic counts and a dissolution index to account for taphonomic processes (Ryves et
al., 2009) are presented from sediment cores obtained from the north basin of the lake
and from the south and central basins, which are believed to be more heavily impacted by
anthropogenic activities. These results highlight the on-going temporal and spatial
changes in the lake ecosystem that are occurring in response to anthropogenic forcing
from both climate change and catchment activities, with observed increases in Synedra
species abundances in the uppermost sediment samples.
Keywords: diatom; nutrient; pollution; climate; Baikal
Ciesielski, T., Pastukhov, M.V., Fodor, P., Bertenyi, Z., Namiesnik, J., Szefer, P. (2006). 'Relationships
and bioaccumulation of chemical elements in the Baikal seal (Phoca sibirica).' Environmental Pollution,
139, 372-384
Hampton, S.E., Izmesteva, L.R., Moore, M.V., Katz, S.L., Dennis, B., Silow, E.A. (2008). ‘Sixty years of
environmental change in the world’s largest freshwater lake – Lake Baikal, Siberia.’ Global Change
Biology, 14, 1947-1958
Mackay, A.W., Flower, R.J., Kutmina, A.E., Granina, L., Rose, N.L., Appleby, P.G., Boyle, J.F.,
Battarbee, R.W. (1998). ‘Diatom succession trends in recent sediments from Lake Baikal and their
relation to atmospheric pollution and to climate change.’ Phil. Trans. R. Soc. Lond. B., 353, 1011-1055
Ryves, D.B., Battarbee, R.W., Frit, S.C. (2009). ‘The Dilemma of Disappearing Diatoms: Incorporating
Diatom Dissolution Data into Palaeoenvironmental Modelling and Reconstruction.’ Quaternary Science
Reviews, 28, 1-2, 120-136
Timoshkin, O.A. (2007). In: New Scope on the Boreal Ecosystems in East Siberia. Proceedings of the
International Symposium, Kyoto Nov.23–25 1994.
Todd, M.C., Mackay, A.W. (2003). ‘Large-Scale climate controls on Lake Baikal ice cover.’ Journal of
Climate, 16, 3186-3199