Seasonal variability of nutrients and organic carbon in the Kamchatka and Avacha Rivers (Kamchatka Peninsula) in 2023

In 2023, during the main phases of the water regime, four expeditions were carried out to collect water samples from sources to mouths in the Kamchatka and Avacha rivers, flowing into Kamchatka Bay and Avacha Bay of Eastern Kamchatka, respectively. In the r. In Kamchatka, seasonal extremes of concentrations and fluxes with river runoff of dissolved and organic phosphorus, as well as organic carbon, were established during the period of snow melting in the river valley and in the highlands (May–June), which was less in the river. Avacha. The annual fluxes with the runoff of the Kamchatka River and the Avacha River were respectively 4565 and 289 tons/year for Ptot, 9526 and 2006 tons/year for Ntot, 60485 and 3992 tons/year for DOC. The article discusses the sources and fluxes of nutrients in the catchments of the studied rivers and the potential responses of the aquatic ecosystems of the receiving basins in connection with volcanism, including in connection with the eruption of the Shiveluch volcano, which occurred on April 11, 2023.