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RESEARCH PRODUCT
Planktonic rotifer feeding in hypertrophic conditions
S. S. S. SarmaEduardo VicenteS. NandiniMaria Rosa Miraclesubject
CyanobacteriaBotanySestonIngestionRotiferFraction (chemistry)Growth rateBacterioplanktonAquatic ScienceBiologyPlanktonbiology.organism_classificationEcology Evolution Behavior and Systematicsdescription
We studied the role of rotifers as grazers in hypertrophic waters, dominated by poorly edible filamentous and colonial cyanobacteria. Population growth of Anuraeopsis fissa and Brachionus angularis, from hypertrophic lake Albufera in Valencia, was followed for 15 days in three treatments of different food size fractions: (a) 0–15 µm (lake water filtered through 15 µm nytal sieve), (b) 0–3 µm (15 µm lake water filtrate filtered through 3 µm nuclepore filter), and (c) 3–15 µm (re-suspension, in absolute filtered lake water, of the seston collected on the 3 µm filter, after passing lake water previously filtered through 15 µm). None of the species grew when fed the food size fraction of 3–15 µm that contained a large proportion of filamentous and colonial cyanobacteria. A. fissa showed highest growth parameters when fed the <3 µm food size fraction, which was mainly composed of bacterioplankton, but much reduced growth on the whole <15 µm seston fraction. On the other hand, B. angularis showed highest growth on the whole <15 µm seston fraction and a moderate growth when fed only on the <3 µm seston fraction. Clearance, ingestion, and assimilation rates were measured with 3H-thymidine plus 3H-leucine-labeled lake bacteria community, suspended in the 15 and 3 µm lake water filtrates. B. angularis had higher rates than A. fissa, and both had higher rates when suspended in the <3 µm seston fraction. Our results confirm that bacteria are the dominant food source for both species in this hypertrophic lake, but clear niche differences separate them. A. fissa is more dependent on smaller food particles and is more sensitive to dense blooms of colonial and filamentous cyanobacteria than B. angularis. The distinct feeding abilities of these species shape their differential distributions in space and time.
year | journal | country | edition | language |
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2014-02-07 | International Review of Hydrobiology |