Colonization dynamics of ciliate morphotypes modified by shifting sandy sediments

• Published in: European journal of protistology Vol. 50; no. 4; pp. 345 - 355
• Main Authors: Risse-Buhl, Ute, Felsmann, Katja, Mutz, Michael
• Format: Journal Article
• Language: English
• Published: Munich Elsevier GmbH 01.08.2014; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Bacterial Load; Bacterial Physiological Phenomena; Bedload; Biological and medical sciences; Ciliophora - cytology; Ciliophora - growth & development; Ciliophora - physiology; Feeding strategy; Fresh water ecosystems; Fundamental and applied biological sciences. Psychology; Geologic Sediments - parasitology; Hyporheic zone; Population Dynamics; Protists; Protozoa; Ripple; Rivers - parasitology; Stream; Synecology; Systematics. Geographical distribution. Morphology. Cytology; Water Microbiology; Feeding strategy; Hyporheic zone; Ripple; Protists; Stream; Bedload; Protozoa; Sediments; Morphotype; Freshwater environment; Strategy; Ciliata; Colonization
• ISSN: 0932-4739; 1618-0429; 1618-0429
• DOI: 10.1016/j.ejop.2014.03.006

Sandy stream-bed sediments colonized by a diverse ciliate community are subject to various disturbance regimes. In microcosms, we investigated the effect of sediment shifting on the colonization dynamics of 3 ciliate morphotypes differing in morphology, behavior and feeding strategy. The dynamics of the ciliate morphotypes inhabiting sediment pore water and overlying water were observed at 3 sediment shifting frequencies: (1) stable sediments, (2) periodically shifting sediments such as migrating ripples, and (3) continuously shifting sediments as occurring during scour events of the uppermost sediment. Sediment shifting significantly affected the abundance and growth rate of the ciliate morphotypes. The free-swimming filter feeder Dexiostoma campylum was vulnerable to washout by sediment shifting since significantly higher numbers occurred in the overlying water than in pore water. Abundance of D. campylum only increased in pore water of stable sediments. On the contrary, the vagile grasper feeder Chilodonella uncinata and the sessile filter feeder Vorticella convallaria had positive growth rates and successfully colonized sediments that shifted periodically and continuously. Thus, the spatio-temporal pattern of sediment dynamics acts as an essential factor of impact on the structure, distribution and function of ciliate communities in sand-bed streams.