Diffusive emission of carbon dioxide and hydrogen sulfide from Valley of Death, Kamchatka, Russia

Valley of Death, discovered almost half a century ago and located in the very upper reaches of the river Geysernaya, about 7 km from the Geyser Valley in Kamchatka, is famous for occurrences of dead animals there. During field work in August 2023, the soil CO2 flux was measured using the accumulation chamber method in the lower section of the Valley of Death. On an area of 6.2 x 10(3) m(2), the flux was measured at 100 randomly distributed points. At several points a MultiGas device was used for analysis of the composition of soil gases (CO2, H2S, SO2). Data processing showed the presence of a single "hydrothermal" population of the CO2 flux. The average CO2 flux was found to be 1272 g m- 2 d(-1), with the maximum value of 28,984 g m- 2 d-(1). The average weight ratio of CO2/H2S was 14.7 +/- 4, and thus, the "deadly" part of the surface of Death Valley in August 2023 emitted -8 t d(-1) of CO2 and - 0.54 t d(-1) of H2S. The soil temperature at the measurement points was close to the air temperature and did not correlate with the CO2 flux. Such value of the CO2 flux corresponds not <3.5 kg s(-1) of hydrothermal steam condensed beneath the degassing part of Valley of Death.