Title: The vertical distribution of some ciliated Protozoa in the plankton of a eutrophic pond during summer stratification
Abstract: Summary The vertical distribution of some ciliated Protozoa in the plankton of a pond in north‐west England was investigated during August 1971. At this time, when the pond was stratified with an oxygen dificient hypolimnion, ciliates were counted at 10‐cm depth intervals every 5 h over 25 h. The most common species ( Loxodes magnus and L. striatus ) were confined to the hypolimnion; there was no diurnal migration into the epilimnion. Earlier work had shown that Loxodes species require oxygen; it is therefore possible that these ciliates, which inhabited the oxygen dificient hypolimnion, migratedvertically, from time to time, to an oxygen supply at the boundary with the well‐oxygenated epilimnion. To test this, Loxodes populations were confined in cellophane tubese both in the hypolimnion (at 3 m) and epilimnion (0.5 m) for 12 and 24 h (earlier trials had shown that the tubes were not markedly toxic). The ciliates died at both depths, and in a further experiment when Loxodes were confined at 3 m and 0.5 m and sampled at 5‐h intervals up to 25 h it was found that they survived longer in the hypolimnion. It is suggested that ciliatees confined at 3 m died because they were unable to migrate vertically to an oxygen supply, while those at 0.5 m died because some other adverse factor was operating in the eiplimnion. Laboratory experiments showed that Loxodes died inn water in which phytoplankton photosynthesis took place and it is suggested that side effects of photosynthesis in the epilimnion (e.g. a rise in pH) caused the death of ciliates exposed at 0.5 m.
Publication Year: 1972
Publication Date: 1972-06-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 35
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot