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Relationships of body length (L) and filtering rate (fl of four Daphnia species and Holopedium gibber-urn were examined in situ during the day' and night, During the day filtering rates were low and variable. At night filtering rates were higher and more consistent, with large animals filtering at disproportionately high rates. This resulted in regressions(More)
Aerial respiratory behavior in Lymnaea was operantly conditioned so that the animals perform aerial respiration significantly less often. Using the standard training procedure (pond water made hypoxic by bubbling N2 through it) both food-deprived and fed animals learned and exhibited long-term memory (LTM). However, food-deprived animals exhibited neither(More)
Isolated female D. leptopus oscillate between gravid and nongravid reproductive conditions. When gravid, the oviducts are visible as a pair of dark bands lateral to the digestive tract. Periodically the females revert to a nongravid condition by releasing all the unfertilized oocytes into the environment. The oviducts then remain transparent until they(More)
The filtrate from a suspension of the cyanobacterium Anabaena minutissima var. attenuata depressed thoracic limb beat frequency of Daphnia carinata by 38–45% in a food-free medium. Repeated exposure to the filtrate produced a similar depression of activity with full or neary full recovery. Response time to the filtrate was 5–8 min and recovery time was 8–12(More)
Experiments were run to determine the effect of filtrate from incubated Aphanizomenonflos-aquae on the thoracic appendage beat rate and frequency of postabdominal rejections by Daphnia carinata. Comparisons were made between the response to Aphanizomenon filtrate and to purified saxitoxin (STX). The short-term response pattern to the filtrate included an(More)
Cyanobacteria produce many neurotoxins including beta-methylamino-L-alanine (BMAA) that has been liked to amyotrophic lateral sclerosis (ALS) and neurodegenerative disease. A number of ALS cases have been diagnosed among residents of Enfield, NH, a town encompassing a lake with a history of cyanobacteria algal blooms. To investigate an association between(More)
Zooplankton accumulate microcystins (MC), a potent cyanobacteria toxin, and therefore may act as vectors of the toxin up the aquatic food web; however this transfer has not yet been quantified. In addition there is a lack of information regarding fish's ability to metabolize MC when administered a low dose over a longer period of time. We monitored MC(More)
The activity of the degradation products of linoleic and linolenic acids in inhibiting the growth of the green alga Chlorella pyrenoidosa was determined using the paper disk-agar plate method. Although hydroperoxides derived from these acids and aldehyde biodegradation products and other related aldehydes and alcohols showed inhibitory activity, it is(More)
Volatile organic compounds produced by cyanobacteria and algae in freshwater lakes and contributing to the odour of lakes were tested for their ability to inhibit the growth of the green alga Chlorella pyrenoidosa by the paper disk-agar plate method. Geosmin, β-cyclocitral, α- and β-ionones, and geranylacetone exhibited inhibitory activity by diffusion in(More)