Вплив з’єднувального каналу Куяльник – Чорне море на показники зоопланктону

Changes in the qualitative and quantitative indicators of mesozooplankton in seawater flowing througha special channel from the Odessa Bay of the Black Sea to the Kuyalnytsya estuary are considered in order tomaintain the permissible level of salinity. This is the first study in the world of the impact of a high-velocitycanal on zooplankton for seawater. In 2017, during the operation of the connecting channel (in the cold waterperiod), a comparison of zooplankton indicators was performed at sea and at the exit from the channel. As a resultof passing through the canal, the quantitative indicators of zooplankton decreased by an order of magnitude:the number at sea – 18372 ind. ∙ m-3 and at the exit from the canal – 398 ind. ∙ m-3; biomass – 60.0 mg ∙m-3 and 2.0 mg ∙ m-3, respectively. The percentage of losses fluctuated by seasons and ranged from 41% (April) to99% (February) in number, and from 27% (March) to 99% (February and December) in biomass. Such a large runwas associated with changes in the qualitative composition of zooplankton. Zooplankton of the study period wasrepresented by 11 taxa. Its constant component at sea and at the exit of the canal was Acartia clausi + tonsa. Insome months, the following representatives of zooplankton were present only in the sea: in April, the eutrophicindicator Noctiluca scintillans (Macartney) Kofoid & Swezy, 1921 (40 ind. ∙ m-3, 1.8962.0 mg ∙ m-3), and –Rissoa splendida Eichwald, 1830 (20 ind. ∙ m-3, 0.140 mg ∙ m-3), and in February – rotifers of the genus Keratella(1400 ind ∙ m-3, 0.700 mg ∙ m-3). All these species did not tolerate passage through the channel: N. scintillans and R. splendida did not pass at all; rotor losses ranged from 88.5% to 99.9%. Minimal losses were observedin Acartia clausi + tonsa from 0% to 83.0%, depending on the stage of development. Based on the calculationsof the monthly volume of water entering the estuary, 43,657 kg of zooplankton entered the estuary duringthe 6 months of the canal’ s operation, which could not harm the estuary resources.