Numerical simulation of the vertical migration of Microcystis (cyanobacteria) colonies based on turbulence drag

Zhao, Hongru; Zhu, Wei; Chen, Huaimin; Zhou, Xiaohua; Wang, Ruochen; Li, Ming

doi:10.4081/jlimnol.2016.1501

Cited by 7 publications

(6 citation statements)

References 32 publications

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“…Movement of the Microcystis colony in turbulence can be considered analogous to the sediment transport process in turbulent currents 21 . The turbulent force, , on the Microcystis population under wind-driven current disturbance is composed of turbulent drag, virtual mass, and pressure-gradient forces.…”

Section: Methodsmentioning

confidence: 99%

“…Wu et al 19 observed that Microcystis in Lake Taihu, with a colony size of 36–120 µm, were evenly distributed vertically under windy conditions and congregated at the surface when there was no wind. Laboratory test results from Xiao et al 20 and a numerical simulation test from Zhao et al 21 showed that the ability of Microcystis to resist the disturbance of wind-driven currents is positively correlated with colony size. Microcystis has a resistance limit for turbulent kinetic energy (TKE).…”

Section: Introductionmentioning

confidence: 99%

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Influence of wind and light on the floating and sinking process of Microcystis

Xue

Zhu

et al. 2022

Sci Rep

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The vertical migration and accumulation of Microcystis colonies is a critical process in algal bloom formation. This work explored the effect of wind and light intensity on the vertical migration of Microcystis colonies. The wind-driven currents, light-driven changes in mass density of colonies, and the effect of colony size was coupled to simulate the vertical motion of colonies via Ansys Fluent and MATLAB. Results showed that light causes Microcystis to exhibit a ‘day-sinking and night-floating’ (d-n) phenomenon, however, wind weakens the phenomenon by forming a turbulent drag force that inhibits the vertical movement of Microcystis. This study proposed a kinetic ratio-based method, that there is a specific equilibrium turbulent kinetic energy and when turbulent kinetic energy of the water body is greater than the equilibrium turbulent kinetic energy, the d-n phenomenon does not occur. For Lake Taihu, the wind-driven turbulent kinetic energy is usually greater than the equilibrium turbulent kinetic energy. Therefore, Microcystis colonies may not exhibit the d-n phenomenon. Our findings provide a new theoretical basis for current process-based models in simulating algal blooms in large shallow lakes.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of wind and light on the floating and sinking process of Microcystis

Xue

Zhu

et al. 2022

Sci Rep

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“…Nutrients in the waterbody also play a role in density change [5]. Additionally, turbulence and vertical water velocities can influence vertical migration in cyanobacteria [16].…”

Section: Discussionmentioning

confidence: 99%

“…Microcystis colonies in the Three Gorges Reservoir were observed to migrate to greater depths in open water while those in a protected enclosure stayed closer to the surface [12]. Zhao et al [16] found that Microcystis spp. (mainly M. aeruginosa) in a laboratory experiment could maintain buoyancy up to a critical value of turbulent kinetic energy, and that this value increased with colony size.…”

Section: Introduction 1backgroundmentioning

confidence: 99%

Modeling Cyanobacteria Vertical Migration

Overman

Wells

2022

Water

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Cyanobacteria often cause harmful algal blooms and release toxic substances that can harm humans and animals. Accurately modeling these phytoplankton is a step towards predicting, preventing, and controlling such blooms. Certain cyanobacteria species are known to migrate vertically in the water column on a daily cycle. Capturing this behavior is one aspect of modeling their dynamics. Previous studies on modeling cyanobacterial vertical migration are reviewed and summarized. Several models of cyanobacteria vertical movement are tested using data from field studies. These models are applied using both continuum and particle-tracking frameworks. Models range in complexity from simple functions of time to more complicated calculations of cyanobacteria buoyancy. Simple models were often able to predict cyanobacteria migration at low values of vertical diffusion in both types of modeling frameworks. More complicated models of buoyancy change performed better in the particle-tracking framework than in the continuum framework. Analysis of the models developed and tested provides information on the applicability of these models in more complex hydrodynamic and water quality models.

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“…In turn, colony formation probably benefits 'nutrient, O 2 , and CO 2 exchange within the "phycosphere" by associated bacteria, thus minimizing nutrient (especially P) limitation (Paerl and Millie 1996;Cook et al 2019). Colony formation may also benefit the buildup of Microcystis biomass because of the high resistance of colonies to grazing pressure from zooplankton (Gerphagnon et al 2015), and an increased floating velocity of large colonies allowing more effective light capture in the upper water column even under wind-wave mixing (Zhao et al 2017), which is line with the positive correlation between colony size and biomass (Fig. 6a,b).…”

Section: Discussionmentioning

confidence: 99%

Ecological stoichiometry of functional traits in a colonial harmful cyanobacterium

Duan

Tan

Paerl

et al. 2021

Limnology & Oceanography

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Trait-based approaches provide a mechanistic framework crossing scales from cellular traits to community dynamics, while ecological stoichiometry applies first principles to understand how the balance of energy and elements shape ecological interactions. However, few studies have explicitly linked both frameworks. In this study, we tested the stoichiometric regulation of a number of carbon (C) based (e.g., extracellular polysaccharides and colony formation) and nitrogen (N) containing traits (i.e., chlorophyll a, phycocyanin, and gas vesicle content) in cyanobacteria in laboratory experiments and in the field. We exposed the cosmopolitan colony forming freshwater cyanobacterium Microcystis sp. in batch experiments to light, N and phosphorus (P) limitation, and enhanced CO 2 levels, and assessed the regulation of these traits. Cyanobacterial traits followed stoichiometrically predictable patterns, where N containing traits increased with cellular N content, and decreased with increasing C : N ratios. C-based traits increased with cellular C content and C : N ratios under nutrient, particularly N, limitation. The pattern of colony formation was confirmed with field data from Lake Taihu (China), showing an increase in colony size when N was limiting and N : P ratios were low. These findings demonstrate how an explicit coupling of trait-based approaches to ecological stoichiometry can support our mechanistic understanding of responses of cyanobacteria toward shifts in resource availability.

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Numerical simulation of the vertical migration of Microcystis (cyanobacteria) colonies based on turbulence drag

Abstract: The

Cited by 7 publications

References 32 publications

Influence of wind and light on the floating and sinking process of Microcystis

Influence of wind and light on the floating and sinking process of Microcystis

Modeling Cyanobacteria Vertical Migration

Ecological stoichiometry of functional traits in a colonial harmful cyanobacterium

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