The synergetic effects of turbulence and turbidity on the zooplankton community structure in large, shallow Lake Taihu

Abstract

Climate change is predicted to influence the heat budget of aquatic ecosystems and, in turn, affect the stability of the water column leading to increased turbulence coupled with enhanced turbidity. However, the synergetic effects of turbulence and turbidity on zooplankton community structure remain to be understood in large, shallow lakes. To determine the possible synergetic effects of these factors on zooplankton communities, a 15-day mesocosm experiment was carried out and tested under four turbulence and turbidity regimes namely control (ɛ = 0, 7.6 ± 4.2 NTU), low (ɛ = 6.01 × 10 m s, 19.4 ± 8.6 NTU), medium (ɛ = 2.95 × 10 m s, 55.2 ± 14.4 NTU), and high (ɛ = 2.39 × 10 m s, 741.6 ± 105.2 NTU) conditions, which were comparable to the natural conditions in Lake Taihu. Results clearly showed the negative effects of turbulence and turbidity on zooplankton survival, which also differed among taxa. Specifically, increased turbulence and turbidity levels influenced the competition among zooplankton species, which resulted to the shift from being large body crustacean-dominated (copepods and cladocerans) to rotifer-dominated community after 3 days. The shift could be associated with the decrease in vulnerability of crustaceans in such environments. Our findings suggested that changes in the level of both turbidity and turbulence in natural aquatic systems would have significant repercussions on the zooplankton communities, which could contribute to the better understanding of community and food web dynamics in lake ecosystems exposed to natural mixing/disturbances.

Assessment of the Impact of the Nile Flood on Food Chain in Lake Nasser—Egypt, with Special Reference to Turbidity

“…The changes in zooplankton during the two sampling seasons coincided with those of the phytoplankton and are concurrent with turbidity, as reported by [37] [38]. Besides, the competition among plankton species was intensified as a result of the turbidity of the water [39]. These results are similar to that obtained by [34] which concluded that the southern part (upstream) is richer in zooplankton than the northern one (downstream), as in Figure 6, and this coincided with the increased nutrient level in the water coming with the flood [40].…”

Environmental constraint of intraguild predation: Inorganic turbidity modulates omnivory in fairy shrimps

“…Changes in inorganic turbidity can lead to significant shifts in community composition (Teffera et al, 2018;Zhou et al, 2018).…”

“…As suspended inorganic particles (e.g. clay, silt; Eiler et al, 2003) interfere with the filter-feeding process (Kirk & Gilbert, 1990), their high concentration in the water is expected to have a negative effect on zooplankters (Dejen, Vijverberg, Nagelkerke, & Sibbing, 2004;Teffera et al, 2018;Zhou, Qin, & Han, 2018). There is, however, a difference among suspension feeders in their ability of coping with (often extreme) turbid conditions.…”

Functional responses of Daphnia magna to zero-mean flow turbulence

“…Although turbulence might enhance the food capture capacity of D. magna individuals 22,52,53 , at ε > ε cr , the mechanical movement was inhibited. Other authors have found turbulence to affect or disturb vertical refuge for zooplankton 54 and/or zooplankton community composition through changes in phytoplankton 55 and predation 56,57 . Therefore, high levels of turbulence will inhibit D. magna swimming, affect survival and increase the contact of D. magna individuals with their preys 4,8,58 .…”