SGEM SGEM 2021. 21th International Multidisciplinary Scientific GeoConference. Volume 21. Water Resources. Forest, Marine and Ocean Ecosystems : conference proceedings of selected papers. 16-22 August, 2021 - Albena, Bulgaria Issue 3.1 Hydrology and Water Resources, Marine and Ocean Ecosystems, Forest Ecosystems, Soils. -- 1. vyd. -- Sofia : STEF 92 Technology, 2021. -- 736 s. -- ISBN : 978-619-7603-24-8. -- 978-619-7603-25-5 (DVD). -- ISSN : 1314-2704. -- 10.5593/sgem2021/3.1.