Green, Jim (1998) Plankton associated with medusae of the freshwater jellyfish Craspedacusta sowerbyi (Lankester) in a Thames backwater. Freshwater Forum, 11, pp. 69-76.
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Samples of plankton were taken from Broom Water in August 1997 after a sighting of medusae on 11th August. Broom Water is about 8 m wide, and extends 250 m from the main channel of the Thames, above the weir at Teddington. On 11th August medusae were so abundant that it was possible to collect 20 in ten minutes. They were rising to the surface in bright sunlight, then sinking slowly down through the water. Examination of a medusa's tentacles under a microscope revealed the presence of a commensal protozoan, a ciliate Trichodina pediculus. Over 20 species of phytoplankton were found in Broom Water. Most of the species are common and widespread, but it was a surprise to find Errerella bornhemiensis with its characteristic pyramidal colonies, which is a relatively rare species. Zooplankters in Broom Water consisted of Rotifera and Crustacea. Zooplankton is the main food of Craspedacusta and it was found that the crustaceans but not the rotifers did undergo significant changes during the period 11-19th August. The major changes were a big increase in the percentage of cyclopoids, and a marked decrease in Bosmina. This could be because the delicate cuticle of Bosmina is much more susceptible to the stinging cells of the medusae compared with the tougher exoskeleton of the cyclopoid.
|Title:||Plankton associated with medusae of the freshwater jellyfish Craspedacusta sowerbyi (Lankester) in a Thames backwater|
|Journal or Publication Title:||Freshwater Forum|
|Page Range:||pp. 69-76|
|Issuing Agency:||Freshwater Biological Association|
|Uncontrolled Keywords:||Backwaters; Commensalism; Epibionts; Food webs; Freshwater crustaceans; Interspecific relationships; Predation; Species diversity; Zooplankton; England; Thames river; Craspedacusta sowerbyi|
|Depositing User:||Hardy B Schwamm|
|Date Deposited:||26 Nov 2010 13:40|
|Last Modified:||29 Sep 2011 18:11|
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