Abstract
The effects of water turbulence on rotifer communities were experimentally studied under different predation pressures. When the larvae of the phantom midge (Chaoborus flavicans) were present in turbulent water, the abundance of most rotifer taxa was enhanced. Especially the genera Chromogaster, Keratella, Polyarthra, and Trichocerca, increased in abundance. In calm water, chaoborids did not affect the rotifer community. In turbulent water predation by chaoborids was targeted more towards cladocerans (Bosmina sp.) and predation pressure on rotifers was relaxed. Additionally, reduced competition with cladocerans probably contributed to the increase of rotifer abundance. Turbulence alone had no significant effect on rotifer abundance because their individual size was small compared with the diameter of the turbulent eddies. The study suggested that the effects of turbulence on rotifers is not direct but takes place through changed predator–prey relations, i.e., the effect depends on the abundance of invertebrate predators. In aquatic ecosystems with a high density of chaoborids, increasing turbulence can considerably increase the abundance of rotifers.
Highlights
Small-scale turbulence is an abiotic factor that contributes to the feeding of aquatic animals by affecting encounter rates between predators and prey and thereby influencing ingestion rates of predators (Rothschild & Osborn, 1988; Marraseet al., 1990; Harkonen et al, 2014a)
The present study suggested that intermediate turbulence alone does not have a direct influence on rotifers
This was expected because the effect of turbulence on planktonic organisms depends on the size of the organisms in relation to the size of the turbulent eddies
Summary
Small-scale turbulence is an abiotic factor that contributes to the feeding of aquatic animals by affecting encounter rates between predators and prey and thereby influencing ingestion rates of predators (Rothschild & Osborn, 1988; Marraseet al., 1990; Harkonen et al, 2014a). Studies on the effects of turbulence on rotifers, which are usually clearly smaller than crustacean zooplankton and in size range of 100–700 lm, have been relatively sparse and conclusions have been variable. Both positive and negative responses of rotifers to increasing turbulence have been reported (Miquelis et al, 1998; Sluss et al, 2008; G.-Toth et al, 2011; Zhou et al 2018). Any disturbance affecting rotifer communities may influence the whole aquatic food web, and turbulence levels in many aquatic ecosystems are probably increasing due to increasing wind speeds and decreasing water levels, and these changes will influence the planktonic communities (Pryor et al, 2005; G.-Toth et al, 2011)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
