Citation :
« Winner of many international awards, this classic natural history film examines the ecology of a marsh and represented a major development in the genre. It avoids the cute, anthropomorphic approach then common in natural history films in favour of respecting its subject and its audience. World in a Marsh was also released theatrically in the Canada Carries On series in a shortened version titled The Lively Pond. »
-- Peter Morris

Source :
FILM REFERENCE LIBRARY. « Canadian Film Encyclopedia », Film Reference Library (Toronto International Film Festival Group), http://cfe.tiff.net/canadianfilmencyclopedia/. (s.v. 'World in a Marsh') [en anglais]