Eleven- and ten-year basic cycles of Lake Baikal spring phytoplankton conformed to solar activity cycles

The paper presents an analysis and discussion on a phenomenon of Lake Baikal spring phytoplankton known as ‘melosira years,’ or high-productive years, which are years when spring a psychric set of planktonic algae intensively blooms in the interstitial water within the thawing ice and in the under-ice water. Alternative of these high- and low-productive years is one of greatest baikalian mysteries long attracting researchers’ attention. Analysis of a sequence of high-productive years from 1943 to present, allowed us to reveal 11- and 10-year cycles in long-term dynamics of the Lake Baikal spring phytoplankton. Within these basic cycles we have found enclosed three intervals between high-productive years. Moreover, these intervals being usually 3 and 4 years long became doubled, i.e., 6 and 8 years long, from 1968 to 1990 that equals 22 years in length, or two 11-year fragments. This phenomenon of doubling can be explained in terms of the resonance theory so we consider the ‘melosira years’ phenomenon to be bound up with solar activity, resonantly influencing baikalian phytoplankton. Also we found that Lake Baikal spring phytoplankton skip between their 11- and 10-year cycles in conforming to a current solar activity length.