aquatic ecology 1 [vynechat] dejiny 1 [vynechat] dejiny objavov a vynálezov 1 [vynechat] discoveries and inventions 1 [vynechat] ekohydrológia 1 [vynechat] environmental management 1 [vynechat] environmentálny manažment 1 [vynechat] history of discoveries and inventions 1 [vynechat] hydrosféra 1 [vynechat] hydrosphere 1 [vynechat] inventors 1 [vynechat] objavitelia a vynálezcovia 1 [vynechat] objavy a vynálezy 1 [vynechat] vodné zdroje 1 [vynechat] water catchment areas 1 [vynechat]