The Evaluation of Sinanodonta Woodiana Application Feasibility as a Microcystis-Blooming Removal Tool in Microcosm Experiments

Abstract

Sinanodonta woodiana is widely distributed throughout Chinese freshwaters and is an important economic pearl mollusk. In order to evaluate the application feasibility of S. woodiana as a Microcystis-blooming removal tool, a series of microcosm experiments were performed. First the 6-day feeding responses experiment was carried out with naturally blooming pond water and the bivalves in laboratory, which was lasted for 6 days. In this experiment, phytoplankton abundances and community structure were analyzed on 0-day and 6-day for both control and treatment microcosms; also, filtration rate, absorption efficiency, oxygen consumption rate and ammonia excretion rate of S. woodiana were measured on 0-day and 6-day and finally the scope for growth (SFG) value as a measure of metabolic energy balance for S. woodiana was calculated and compared. The results showed that Microcystis spp. of colony and unicell were reduced obviously on the 6-day; meanwhile, after six days' exposure to Microcystis-blooming pond water, the SFG value for S. woodiana increased. Furthermore, in the extended long-term grazing experiment, bivalves were fed with highly concentrated toxic Microcystis-blooming water and non-toxic Chlorella at the constant concentration (Chl.a=424.5 mg/m 3 ) in two respective tanks for 12 days. No bivalve mortality was registered on both Chlorella group and blooming water group. In addition, SFGs were significantly higher for the blooming water group, compared with them for Chlorella group on 3-day, 6-day and 12-day. These results indicated that toxic Microcystis spp. in natural eutrophic water can be removed greatly by S. woodiana; moreover, the bivalves themselves have strong adaptation ability when they were exposed to toxic natural eutrophic water. Therefore, it can be inferred that there is high application feasibility of S. woodiana as a Microcystis-blooming controller in practice.

POSSIBLE SURVIVAL MECHANISMS OF <i>SINANODONTA WOODIANA</i> EXPOSED TO MICROCYSTIN

“…(2) Six-day feeding responses experiment 6) The experiment was performed at controlled conditions (25 ± 1°C , 12h light:dark cycle, 3400 lux) in four tanks (40 cm × 25.2 cm × 26.2 cm, 20 L liquid). The bivalves of similar size (shell length of 7.45 ± 0.41 cm) were chosen and kept in three replicated treatment tanks (3 bivalves per tank); the rest tank without bivalves was set as control.…”

“…The results of the physiological rates measured in these two experiments are shown in Table 1. (3) Long-term grazing experiment 6) The long-term comparative grazing experiment was carried out to evaluate the effects of toxic cyanobacteria on S. woodiana's feeding and survival. As shown in Fig.1 (a), the culturing part of this experiment was conducted in two tanks (40 cm × 25.2 cm × 26.2 cm) both containing 10 L of filtered water from a pond in Oita, Japan, with 10 bivalves (shell length of 7.32 ± 0.31 cm) at controlled conditions (25 ± 1°C, 12 h light:dark cycle, 3400 lux) with continuous aeration.…”

“…In our previous study, in order to assess the feasibility of applying S. woodiana as a Microcystis blooms removal tool in eutrophic shallow lakes, we performed a series of laboratory experiments: (1) S. woodiana's acute physiological responses to different microalgae diets 5) , (2) six-day feeding response experiment 6) , and the results suggested that not only the pure cultured Microcystis aeruginosa, but also the naturally blooming toxic Microcystis spp. of unicell and colony can be grazed greatly by S. woodiana; moreover, in the following long-term grazing experiment 6) , the bivalves themselves have shown strong adaptation ability when they were exposed to toxic natural eutrophic water for 12 days 6) . In accordance with the phenomena of A (S).…”

Texture of the Freshwater Shells from the Unionidae Family Collected in the Czech Republic Investigated by X-ray and Neutron Diffraction

“…(ii) Sinanodonta woodiana (I. Lea, 1834) is a non-native species in the Czech Republic (and in the whole of Europe), and is spreading to an increasing number of localities and thus oppressing the original species [16]. This species is also very sensitive to water pollution and is an indicator of water purity [17].…”