1. Малахова Т. В. (Malakhova T. V.)
2. Артёмов Ю. Г. (Artemov Yu. G.)
3. Мурашова А. И. (Khurchak A. I.)
4. Решетник Л. В.
   
   ФИЦ «Институт биологии южных морей имени А. О. Ковалевского РАН»
5. Fedirko A. V.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)
6. Егоров В. Н. (Egorov V. N.)

Methods and Results. The surveys were performed in the 113th cruise of the R/V Professor Vodyanitsky (June, 2020) in the upper 100-m layer at the deep-water station (1570 m) in the northeastern Black Sea, and at the shallow-water station (39 m) in the Yalta Bay. The differences in vertical distribution of the CH₄ concentration in the seawater in these areas were found. Diurnal range of the CH₄ concentrations in the surface water layer (0–1 m) was 0.8–16 nmol/l and 0.2–7 nmol/l for the shallow and deep-water areas, respectively. Shown was the fluxes’ high variability at the water – atmosphere boundary in course of a day, namely, from the atmospheric CH4 inflow to the seawater up to the CH₄ emission (up to 3 μmol/m²day) to the atmosphere.

Conclusions. The maximum CH₄ fluxes to the atmosphere recorded at both stations were observed at night. It was shown that the atmospheric CH₄ emission to seawater was not a significant factor in the CH₄ redistribution in a water column since the calculated values of the atmosphere – seawater specific daily CH₄ flux constituted the fractions of a percent of its store in the water column. Diurnal dynamics of the vertical CH₄ distribution and SSL in the aerobic layer of the deep-water station was revealed to be of a similar pattern. Against high variability of the data for the individual time ranges, obtained were significant determination coefficients between the CH₄ concentration and the sound-scattering coefficient of layer ml' as a characteristic of the biomass amount.