Mitigating harmful cyanobacterial blooms in drinking water reservoirs through in-situ sediment resuspension

¹ State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences
² School of Environment and Spatial Informatics, China University of Mining and Technology
³ Zhejiang Weicheng Huanbao Co. Ltd.
⁴ Management Station of Shuangxikou Reservoir, Reservoir Management Service Center of Yuyao
⁵ School of Civil Engineering, Chang’an University
⁶ University of Chinese Academy of Sciences

^✉ Correspondence: Ming Su <mingsu@rcees.ac.cn>, Min Yang <yangmin@rcees.ac.cn>

Supplementary Material

Figures and/or tables are provided below as the supplementary evidences to the main text.

Test in laboratory simulators

Fig. S1 ‎ The figure illustrated the protocol of Sediment Resuspension in laboratory simulators. As shown above, SR operation was periodically conducted in LEs for two minutes (then settled for the following 118 mins) every 2 hours from 7:00 to 19:00 during the first day (Stage SR-ON). No SR operation was performed for all three simulators from day 11 to day 40 (Stage SR-OFF). Besides, the unique light source was switched on from 7:00 to 19:00 during six SR cycles to provide light for the growth of algae. Water and sediments samples were collected before the first SR cycle began. The sampling frequency was every day during Stage SR-ON and one every 2 days during Stage SR-OFF (no samples were collected during day 21–30 due to COVID 19 constraints).

Field applications

Field applications in five drinking water reservoirs

Equipment operational parameters, basic feature and sampling of five reservoirs

Reservoir	SMH	SXK	NJ	CX	HM
Depth (m)	10.5	28.7	7.8	4	6.4
Work area (ha)	25	18	26.5	3.8	12
Risk area (ha)	12	6.4	14.3	1.3	4.12
Numbers of boats	1	1	2	3	3
Work time (d)	180~210	180~210	14	11	10
Work hour (h/d)	10	10	10	10	10
Frequency (1/d)	0.625	1.172	1.049	17.31	5.461
Investigation time	Apr.~Oct., 2023	Apr.~Oct., 2023	Sep., 2021	Jul., 2022	Oct., 2023
Dominant genus	Achnanthes; Microcystis	Pseudanabaena; Raphidiopsis	Microcystis; Synedra	Microcystis	Raphidiopsis
Sampling frequency	biweekly	biweekly	daily	daily	daily
Sampling depth (m)	0.5;3.0;6.0	0.5;3.0;6.0	0.5;3.0;6.0	0.5;2.0;4.0	0.5;3.0;6.0
Collect sediment?	yes	yes	no	no	no

Table S1 ‎ Equipment operational parameters, basic characteristics of algal blooms, and sampling protocols in five drinking water reservoirs.

The changes in turbidity and extinction coefficient during a single SR operation

Fig. S3 ‎ The changes in turbidity over time during a single SR operation (repeated three times, n = 3) in the field test of SXK Reservoir (A); The changes in extinction coefficient over time in SR cycles (n = 60) during LEs tests (B). Each data point represents the mean value of the respective measurements.

The difference in dissolved nitrogen and dissolved organic carbon during SR operation

Fig. S5 ‎ Comparison of total dissolved nitrogen (TDN) and dissolved organic carbon (DOC) between SR-operated samples (LC, FC) and untreated samples (LEs, FE) in laboratory simulators and field applications. Panel A illustrates the difference in TDN between SR-operated samples and untreated samples within laboratory simulators (p-value = 0.0116), three short-term SR-operated reservoirs (CX, NJ and HM Reservoirs, p-value = 0.4445), and two long-term SR-operated reservoirs (SMH and SXK Reservoirs, p-value = 0.8324). Panel B illustrates the difference in DOC between SR-operated samples and untreated samples within laboratory simulators (p-value = 0.6713) and three short-term SR-operated reservoirs (p-value = 0.1104).

Improvement of sediment quality in laboratory simulators

Fig. S6 ‎ Interfacial oxide layer was formed between the sediment and the water phase in laboratory simulators with 10 days’ SR operation (LE, B) in comparison with untreated control set (LC, A).

Evaluation of algae control effect and phosphorus changes during SR OFF in laboratory simulators

Fig. S7 ‎ The dynamics of Microcystis cell density in LEs (LE1 & LE2) during Stage SR-ON (days 1–10) and Stage SR-OFF (days 11–20) are depicted. *Microcystis* cell density decreased during Stage SR-ON but subsequently increased during Stage SR-OFF, providing additional evidence of the impact of SR on algae control.

Fig. S8 ‎ The dynamics of dissolved phosphorus concentration in LC and LEs over the first 20 days are illustrated. Dissolved phosphorus decreased to extremely low levels during SR in both LC and LEs. However, in LC, dissolved phosphorus began to rise significantly between days 11 and 20, with an increase rate of 4.29 μg L^-1 d^-1 (R² = 0.92, p-value = 0.0027). In contrast, increasing rate of LEs was much lower (1.55 μg L^-1 d^-1, R² = 0.53, p-value = 0.007).

Algal control effect of SR in drinking water reservoirs

Fig. S9 ‎ Changes in total algal density over time in FC (without SR operation) and FE (with SR operation) of SMH Reservoir.

Fig. S10 ‎ Changes in total algal density over time in FC (without SR operation) and FE (with SR operation) of SXK Reservoir.

Fig. S11 ‎ Changes in different phylum density over time in CX Reservoir. Specifically, severe *Microcystis* bloom occurred in CX reservoir in October of 2021 and one boat was used to resuspend sediment for emergency algae control. Dynamics of cell density for different phylum in the Reservoir during 10 days SR operation were shown here. Significant decline in cell density especially density of Cyanobacteria occurred after the fourth day of SR operation.

Fig. S12 ‎ The changes in total algal density over time in FC (without SR operation) and FE (with SR operation) of CX Reservoir. During day -6 to day 0, severe cyanobacteria bloom was found in the whole reservoir including FE and FC. During day 1–11, two boats were employed for CX reservoir and conducted SR operation in FE. Decrease rate of 2.043 × 10⁸ cells L^-1 d^-1 in cell density was found in FE, while density remained rising in FC. After day 11, the algae control effect had been confirmed, and the number of boat decreased to one to maintain effectiveness. The following are additional explanations: (1) Comparison of cell densities between SR-operated site (FE) and untreated site (FC) during day 1–11 is shown in Fig. 4B; (2) several images illustrating the changes in water surface from day 0 to day 10 is shown in Fig. 4D.

Fig. S13 ‎ Comparison of cell density between FC and FE in NJ Reservoir. Here, \(C_0\) represented original cell density of FC and FE, and \(C\) represented cell density during SR operation in FE and FC. The dotted line in this figure represented \(C/C_0 = 1\). In more detail, \(C_0\) represented original cell density of FC and FE, and \(C\) represented cell density during SR operation in FE and FC. Therefore, \(C/C_0 > 1\) denoted increase in cell density during our investigation, while \(C/C_0 < 1\) denoted decrease in cell density. Data points of 42 were used for FC and FE in each figure.

Fig. S14 ‎ The changes in total algal density over time in FC (without SR operation) and FE (with SR operation) of HM Reservoir. As shown in the figure, algal density decreased during Stage SR-ON (day 1–11) and stayed in a relatively low level during Stage SR-OFF (day 12–55) in FE. While in FC, algal density increased and stabled at a higher level during the whole investigation in FC. Additionally, comparison of cell densities between FE and FC during day 12–55 is shown in Fig. 4B.

Summary of algal growth rates under various light conditions

Fig. S15 ‎ The effect of light intensity on the growth of cyanobacteria. Data are collected from references: *Cylindrospermopsis* (Bonilla et al., 2012; Briand et al., 2004; Willis et al., 2016; Xiao et al., 2020, 2017), *Microcystis* (Bañares-España et al., 2012; Briand et al., 2012; Hesse et al., 2001; Li et al., 2014; Lürling et al., 2013; Marinho et al., 2013; Mello et al., 2012; Salvador et al., 2016; Sugimoto et al., 2015; Thomas and Litchman, 2015; Torres et al., 2016; Wiedner et al., 2003; Wu et al., 2011; Xiao et al., 2020, 2017), *Pseudanabaena* (Cao et al., 2023; Zhang et al., 2016), *Limnothrix* (Daniels, 2016; Nicklisch, 1999, 1998; Shatwell et al., 2012; Tiwari et al., 2001), *Planktothrix* (Jia et al., 2019; Nicklisch, 1998; Torres et al., 2016), *Planktothricoides* (Lu et al., 2022; Mohanty et al., 2022), *Oscillatoria* (Cai et al., 2017; Foy, 1983; Tang et al., 1997; Tiwari et al., 2001; Van Der Ploeg et al., 1995) and *Synechocystis* (Luimstra et al., 2018).

The changes in Chlorophyll a during a single operation in field tests

Fig. S16 ‎ The changes in Chlorophyll a over time during a single SR operation (repeated three times, n = 3) in the field test of SXK Reservoir (A)

Investigation of dissolved iron and manganese during SR operations in five Reservoirs

Fig. S17 ‎ Comparison of dissolved iron between FC and FE in two reservoirs with long-term SR operation (A) and NJ reservoirs with short-term SR operation (B).

Fig. S18 ‎ Comparison of dissolved manganese between FC and FE in two reservoirs with long-term SR operation (A) and NJ reservoirs with short-term SR operation (B).

References

Bañares-España, E., Kromkamp, J.C., López-Rodas, V., Costas, E., Flores-Moya, A., 2012. Photoacclimation of cultured strains of the cyanobacteriumr Microcystis aeruginosa to high-light and low-light conditions. FEMS Microbiology Ecology 83, 700–710. https://doi.org/10.1111/1574-6941.12025

Bonilla, S., Aubriot, L., Soares, M.C.S., González-piana, M., Fabre, A., Huszar, V.L.m., Lürling, M., Antoniades, D., Padisák, J., Kruk, C., 2012. What drives the distribution of the bloom-forming cyanobacteria Planktothrix agardhii and Cylindrospermopsis Raciborskii? Fems Microbiology Ecology 79, 594–607. https://doi.org/10.1111/j.1574-6941.2011.01242.x

Briand, E., Bormans, M., Quiblier, C., Salençon, M.-J., Humbert, J.-F., 2012. Evidence of the cost of the production of microcystins by microcystis aeruginosa under differing light and nitrate environmental conditions. PLoS ONE 7, e29981. https://doi.org/10.1371/journal.pone.0029981

Briand, J.-F., Leboulanger, C., Humbert, J.-F., Bernard, C., Dufour, P., 2004. CYLINDROSPERMOPSIS RACIBORSKII (CYANOBACTERIA) INVASION AT MID-LATITUDES: SELECTION, WIDE PHYSIOLOGICAL TOLERANCE, ORGLOBALWARMING?1. Journal of Phycology 40, 231–238. https://doi.org/10.1111/j.1529-8817.2004.03118.x

Cai, F., Yu, G., Zhang, K., Chen, Y., Li, Q., Yang, Y., Xie, J., Wang, Y., Li, R., 2017. Geosmin production and polyphasic characterization of Oscillatoria limosa agardh ex gomont isolated from the open canal of a large drinking water system in tianjin city, china. Harmful Algae 69, 28–37. https://doi.org/10.1016/j.hal.2017.09.006

Cao, T., Fang, J., Jia, Z., Zhu, Y., Su, M., Zhang, Q., Song, Y., Yu, J., Yang, M., 2023. Early warning of MIB episode based on gene abundance and expression in drinking water reservoirs. Water Research 231, 119667. https://doi.org/https://doi.org/10.1016/j.watres.2023.119667

Daniels, O., 2016. Autecology, allelopathy and toxicity of Limnothrix (strain AC0243): Multiple-organism studies using laboratory cultures (PhD thesis). University Queensland, Australia.

Foy, R.H., 1983. Interaction of temperature and light on the growth rates of two planktonic Oscillatoria species under a short photoperiod regime. British Phycological Journal 18, 267–273. https://doi.org/10.1080/00071618300650281

Hesse, K., Dittmann, E., BÃrner, T., 2001. Consequences of impaired microcystin production for light-dependent growth and pigmentation of microcystis aeruginosa PCC 7806. FEMS Microbiology Ecology 37, 39–43. https://doi.org/10.1111/j.1574-6941.2001.tb00851.x

Jia, Z., Su, M., Liu, T., Guo, Q., Wang, Q., Burch, M., Yu, J., Yang, M., 2019. Light as a possible regulator of MIB-producing Planktothrix in source water reservoir, mechanism and in-situ verification. Harmful Algae 88, 101658. https://doi.org/10.1016/j.hal.2019.101658

Li, M., Nkrumah, P.N., Xiao, M., 2014. Biochemical composition of microcystis aeruginosa related to specific growth rate: Insight into the effects of abiotic factors. Inland Waters 4, 357–362. https://doi.org/10.5268/IW-4.4.710

Lu, J., Su, M., Su, Y., Wu, B., Cao, T., Fang, J., Yu, J., Zhang, H., Yang, M., 2022. Driving forces for the growth of MIB-producing Planktothricoides raciborskii in a low-latitude reservoir. Water Research 118670. https://doi.org/10.1016/j.watres.2022.118670

Luimstra, V.M., Schuurmans, J.M., Verschoor, A.M., Hellingwerf, K.J., Huisman, J., Matthijs, H.C.P., 2018. Blue light reduces photosynthetic efficiency of cyanobacteria through an imbalance between photosystems I and II. Photosynthesis Research 138, 177–189. https://doi.org/10.1007/s11120-018-0561-5

Lürling, M., Eshetu, F., Faassen, E.J., Kosten, S., Huszar, V.L.M., 2013. Comparison of cyanobacterial and green algal growth rates at different temperatures. Freshwater Biology 58, 552–559. https://doi.org/10.1111/j.1365-2427.2012.02866.x

Marinho, M.M., Souza, M.B.G., Lürling, M., 2013. Light and phosphate competition between cylindrospermopsis raciborskii and microcystis aeruginosa is strain dependent. Microbial Ecology 66, 479–488. https://doi.org/10.1007/s00248-013-0232-1

Mello, M.M. e., Soares, M.C.S., Roland, F., Lurling, M., 2012. Growth inhibition and colony formation in the cyanobacterium microcystis aeruginosa induced by the cyanobacterium cylindrospermopsis raciborskii. Journal of Plankton Research 34, 987–994. https://doi.org/10.1093/plankt/fbs056

Mohanty, B., Majedi, S.M., Pavagadhi, S., Te, S.H., Boo, C.Y., Gin, K.Y.-H., Swarup, S., 2022. Effects of light and temperature on the metabolic profiling of two habitat-dependent bloom-forming cyanobacteria. Metabolites 12, 406. https://doi.org/10.3390/metabo12050406

Nicklisch, A., 1999. Competition between the cyanobacterium limnothrix redekei and some spring species of diatoms under p-limitation. International Review of Hydrobiology 84, 233–241. https://doi.org/https://doi.org/10.1002/iroh.199900024

Nicklisch, A., 1998. Growth and light absorption of some planktonic cyanobacteria, diatoms and chlorophyceae under simulated natural light fluctuations. Journal of Plankton Research 20, 105–119. https://doi.org/10.1093/plankt/20.1.105

Salvador, D., Churro, C., Valério, E., 2016. Evaluating the influence of light intensity in mcyA gene expression and microcystin production in toxic strains of Planktothrix agardhii and Microcystis aeruginosa. Journal of Microbiological Methods 123, 4–12. https://doi.org/10.1016/j.mimet.2016.02.002

Shatwell, T., Nicklisch, A., Köhler, J., 2012. Temperature and photoperiod effects on phytoplankton growing under simulated mixed layer light fluctuations. Limnology and Oceanography 57, 541–553. https://doi.org/10.4319/lo.2012.57.2.0541

Sugimoto, K., Negishi, Y., Amano, Y., Machida, M., Imazeki, F., 2015. Roles of dilution rate and nitrogen concentration in competition between the cyanobacterium microcystis aeruginosa and the diatom cyclotella sp. In eutrophic lakes. Journal of Applied Phycology 28, 2255–2263. https://doi.org/10.1007/s10811-015-0754-7

Tang, E.P.Y., Tremblay, R., Vincent, W.F., 1997. CYANOBACTERIAL DOMINANCE OF POLAR FRESHWATER ECOSYSTEMS: ARE HIGH-LATITUDE MAT-FORMERS ADAPTED TO LOW TEMPERATURE?1. Journal of Phycology 33, 171–181. https://doi.org/10.1111/j.0022-3646.1997.00171.x

Thomas, M.K., Litchman, E., 2015. Effects of temperature and nitrogen availability on the growth of invasive and native cyanobacteria. Hydrobiologia 763, 357–369. https://doi.org/10.1007/s10750-015-2390-2

Tiwari, O., Prasanna, R., Yadav, A., Wattal, D., Singh, P., 2001. Growth potential and biocide tolerance of non-heterocystous filamentous cyanobacterial isolates from rice fields of uttar pradesh, india. Biology and Fertility of Soils 34, 291–295. https://doi.org/10.1007/s003740100402

Torres, C.D.A., Lürling, M., Marinho, M.M., 2016. Assessment of the effects of light availability on growth and competition between strains of Planktothrix agardhii and Microcystis aeruginosa. Microbial Ecology 71, 802–813. https://doi.org/10.1007/s00248-015-0719-z

Van Der Ploeg, M., Dennis, M., De Regt, M., 1995. Biology of Oscillatoria chalybea, a 2-methylisoborneol producing blue-green alga of Mississippi Catfish Ponds. Water Science and Technology 31, 173–180. https://doi.org/10.1016/0273-1223(95)00473-Z

Wiedner, C., Visser, P.M., Fastner, J., Metcalf, J.S., Codd, G.A., Mur, L.R., 2003. Effects of light on the microcystin content of Microcystis strain PCC 7806. Applied and Environmental Microbiology 69, 1475–1481. https://doi.org/10.1128/aem.69.3.1475-1481.2003

Willis, A., Chuang, A.W., Woodhouse, J.N., Neilan, B.A., Burford, M.A., 2016. Intraspecific variation in growth, morphology and toxin quotas for the cyanobacterium, cylindrospermopsis raciborskii. Toxicon 119, 307–310. https://doi.org/10.1016/j.toxicon.2016.07.005

Wu, X., Wu, Z., Song, L., 2011. Phenotype and temperature affect the affinity for dissolved inorganic carbon in a cyanobacterium microcystis. Hydrobiologia 675, 175–186. https://doi.org/10.1007/s10750-011-0815-0

Xiao, M., Hamilton, D.P., O’Brien, K.R., Adams, M.P., Willis, A., Burford, M.A., 2020. Are laboratory growth rate experiments relevant to explaining bloom-forming cyanobacteria distributions at global scale? Harmful Algae 92, 101732. https://doi.org/10.1016/j.hal.2019.101732

Xiao, M., Willis, A., Burford, M.A., 2017. Differences in cyanobacterial strain responses to light and temperature reflect species plasticity. Harmful Algae 62, 84–93. https://doi.org/10.1016/j.hal.2016.12.008

Zhang, T., Zheng, L., Li, L., Song, L., 2016. 2-methylisoborneol production characteristics of Pseudanabaena sp. FACHB 1277 isolated from Xionghe Reservoir, China. Journal of Applied Phycology 1–10. https://doi.org/10.1007/s10811-016-0864-x

Other Formats