Search results for "Rotifera"
showing 2 items of 32 documents
Selection of low investment in sex in a cyclically parthenogenetic rotifer
2009
Cyclical parthenogens, which combine asexual and sexual reproduction, are good models for research into the ecological and population processes affecting the evolutionary maintenance of sex. Sex in cyclically parthenogenetic rotifers is necessary for diapausing egg production, which is essential to survive adverse conditions between planktonic growing seasons. However, within a planktonic season sexual reproduction prevents clonal proliferation. Hence, clones with a low propensity for sex should be selected, becoming dominant in the population as the growing season progresses. In this context, we studied the dynamics of the heritable variation in propensity for sexual reproduction among clo…
Responses of zooplankton to cane sugar additions to a small humic lake, Alinen Mustajärvi
2010
The response to projected increase in dissolved organic carbon (DOC) loading to boreal lakes is being studied in lake Alinen Mustajärvi, a small humic lake in southern Finland, where labile DOC concentration has been artificially increased during 2008 and 2009 by monthly additions of cane sugar. As part of this wider project, in this thesis the responses of the zooplankton community to cane sugar addition were studied. Zooplankton samples were collected monthly in the ice-free periods of 2007, 2008 and 2009 and the mean densities and mean carbon biomasses of rotifers and crustacean zooplankton (cladocerans and copepods) were calculated. Stable isotope analyses (δ13C and δ15N) were made for …