Production and hydrochemical characteristics of the estuaries of the rivers of Artemovka and Shkotovka, flowing into the apex of the Ussuri Bay (the Sea of Japan), were studied in the summer of 2011. Because of the high rate of destruction processes, the partial pressure in river waters of the Shkotovka, Arte movka, and Knevichanka (the Artemovka's major tributary) was 800, 1800, and 3700 µatm, respectively. Unlike the Shkotovka R. estuary, the high trophic level of the Artemovka R. and a favorable combination of hydrological and hydrochemical conditions in the study period determined the high rate of production pro cesses (chlorophyll a concentration reached 200 µg/L, oxygen oversaturation was more than twofold, the par tial pressure of carbon dioxide dropped to 25 µatm). A conservative and nonconservative dependence of alka linity on salinity was also found to exist in the water of the Shkotovka and Artemovka rivers, respectively.