Lake ice is an essential and integral part of the cryosphere and freshwater systems. The formation of lake ice affects the physical, hydrological, and biological conditions of ecological systems.

Even though winter is not favorable, it has been shown that there is a biological activity in sub-ice water, and that the importance of primary production in ice-covered lakes during winter is increasingly recognized in lake metabolism. This underlines the role of winter ecology in the study of changes in environmental conditions of lakes and their biogeochemical cycles.

A study led by Prof. SONG Kaishan from the Northeast Institute of Geography and Agroecology of the Chinese Academy of Sciences evaluated the growth of phytoplankton in 28 ice-covered lakes across the Songnen Plain to understand how they take part in the whole-ecosystem functioning. The study was published online on Journal of Environmental Management.

The researchers collected a total of 1026 water samples were in April, September, and January during 2014-2018. In the frozen period, despite the limited light availability and low temperature, the phytoplankton survived in sub-ice waters with a low concentration of chlorophyll a (Chla). Its average concentration was positively correlated with the concentration observed in the previous autumn (rp = 0.563, p < 0.01).

According to the regression tree analysis, during the winter period, Chla was mainly related to the concentration of total nitrogen in sub-ice water (TNwater), the concentration difference of total phosphorus between water and ice (TPcd), and the total suspended matter (TSM) (p< 0.05). They could explain the 77.8% of the variance in the Chla concentration of during winter.

There is growing interest in winter ecosystems in terms of phytoplankton to help understand the potentially important implications for annual lake biogeochemical loads and primary productivity. The present study, carried out in the cold region, may serve as a framework for future research or global scaling studies concerning seasonally ice-covered lakes.

The study entitled “Variability of chlorophyll and the influence factors during winter in seasonally ice-covered lakes” has been published online in Journal of Environmental Management.

Contact:

Prof. SONG Kaishan, Ph. D

Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China

Tel: 86-431-85542364

E-mail: songks@iga.ac.cn