image: Winter collection of sediment cores from the bottom of Lake Baikal whilst the lake was frozen. view more
Credit: Image credit: Anson W. Mackay
Wind-driven nutrient upwelling in the world's oldest lake has increased dramatically in the last 2,000 years, according to a study. Lake Baikal in Siberia is the world's oldest lake and a designated World Heritage Site, within which a high number of endemic species have evolved. To uncover how nutrient availability in the lake has changed over time, George Swann, Virginia Panizzo, and colleagues examined the silicon isotope composition of diatoms, which are dominant primary producers, over the past 2,000 years. The authors collected sediment core samples from the lake. Analysis of the fossilized diatoms contained in the sediment indicated a significant increase in silicon availability in the 20th and 21st centuries, a result of nutrient upwelling from the lake's depths. The authors reanalyzed climate records for the time period and found an increase in wind strength over the lake in winter and spring, resulting in deep ventilation and increased mixing of the water. The authors note that increasing water temperatures as ice cover decreases may further increase seasonal wind intensity and mixing. According to the authors, the changes, combined with shoreline eutrophication and other stressors, could alter ecosystem community dynamics in the lake.
Article #20-13181: "Changing nutrient cycling in Lake Baikal, the world's oldest lake," by George E. A. Swann et al.
MEDIA CONTACTS: George E.A. Swann, University of Nottingham, UNITED KINGDOM; e-mail: george.swann@nottingham.ac.uk; Ginnie Panizzo, University of Nottingham, UNITED KINGDOM; e-mail: virginia.panizzo@nottingham.ac.uk
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Journal
Proceedings of the National Academy of Sciences