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Lake Baikal deepwater renewal mystery solved
Author(s) -
Schmid Martin,
Budnev Nikolay M.,
Granin Nick G.,
Sturm Michael,
Schurter Michael,
Wüest Alfred
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl033223
Subject(s) - geology , downwelling , shore , oceanography , advection , stratification (seeds) , climate change , biogeochemical cycle , sedimentary rock , structural basin , upwelling , paleontology , seed dormancy , physics , germination , botany , chemistry , dormancy , biology , environmental chemistry , thermodynamics
Deepwater renewal by intrusions and turbulent diffusion in Lake Baikal is very effective despite the enormous depth of up to 1642 m and the permanently stable stratification below ∼300 m depth. Temperature time series recorded at the bottom of a mooring installed since March 2000 in the South Basin of the lake indicate recurrent freshwater intrusions with volumes of 50 to 100 km 3 , about one order of magnitude larger than previously observed intrusions. Numerous mechanisms have been proposed to explain the advective deep water renewal. Here we present for the first time direct observations which prove that they are caused by coastal downwelling and subsequent thermobaric instability along the steep lake shores. Understanding these mechanisms is an important prerequisite for studying biogeochemical cycles, for predicting the effects of climate change on this unique ecosystem and for evaluating the local climate history from the extraordinary sedimentary record of Lake Baikal.