TY JOUR TI Change in composition of periphyton of filtration elements in recirculation aquaculture systems under combined impact of UV radiation and ultrasound KW periphyton KW biofilter KW recirculation aquaculture system KW ultraviolet KW ultrasound KW purification KW relative frequency of occurrence JO Vestnik of Astrakhan State Technical University. Series: Fishing industry AU Klimov, V.. AU Nikiforov-Nikishin, D.L. AU Kochetkov, N.I. AU Gorbunov, A.. PY 2022 IS PB Astrakhan State Technical University