Biogeochemical behavior of particulate elements in the Hövsgöl‒Ustilimsk water system in Mongolia and Russia

Ko Hosoda, Takahiro Murata, Akihito Mochizuki, Toshiya Katano, Yuji Tanaka, Tetsuro Mimura, Osamu Mitamura, Shin-ichi Nakano, Yuko Sugiyama, Yasuhiro Satoh, Yasunori Watanabe, Ayuriin Dulmaa, Chananbaatar Ayushsuren, Darmaa Ganchimeg, Valentin V. Drucker, Vladimir A. Fialkov, Masahito Sugiyama

We investigated the behavior of particulate elements in the Hövsgöl‒Ustilimsk water system, located between Mongolia and Russia, and discussed the biogeochemical mechanism regulating their dynamics. The composition of particulate ele ments was influenced by the geology in each catchment, and was analyzed using the concentration of particulate Al as an indicator. Results revealed that the behaviors of particulate alkaline earth metals in the Egiin Gol River and those of particulate P and Si in Lake Hövsgöl, the Bratsk Reservoir, and the Ustilimsk Reservoir reflected the biogeochemical conditions of each catchment. Flowing down the Egiin Gol River, decreasing pH provided conditions in which suspended calcium carbonate particles were easily dissolved, and led to a decrease in the concentration of particulate Ca and an increase in that of dissolved Ca. The concentration of particulate Ba was found to be related to that of particulate Al, Ca, and Mn, suggesting that particulate Ba was incorporated in aluminosilicate and carbonate rocks while dissolved Ba was adsorbed to the manganese oxide. In Lake Hövsgöl and the Bratsk and Ustilimsk Reservoirs, the concentrations of particulate P and Si were higher than the estimated values from the abundance of elements in the crust and particulate Al concentration, showing that biological activities increased concentrations of particulate P and Si in the lakes. Overall, the behaviors of particulate elements were regulated by the geological features in each catchment and geochemical character istics of the elements themselves, as well as by biological activities.

Limnology

Springer Nature

https://doi.org/10.1007/s10201-026-00845-9