Effects of Modified Clay on Phaeocystis globosa Growth and Colony Formation.

Xiangzheng Ren,Xihua Cao,Xiuxian Song,Lixia Qiu,Zhiming Yu

doi:10.3390/ijerph181910163

Abstract

Phaeocystis globosa is a globally distributed harmful algal blooms (HABs) species dominated by the colonial morphotype, which presents dramatic environmental hazards and poses a threat to human health. Modified clay (MC) can effectively flocculate HAB organisms and prevent their subsequent growth, but the effects of MC on colony-dominated P. globosa blooms remain uncertain. In this paper, a series of removal and incubation experiments were conducted to investigate the growth, colony formation and colony development of P. globosa cells after treatment with MC. The results show that the density of colonies was higher at MC concentrations below 0.2 g/L compared to those in the control, indicating the role of P. globosa colonies in resistance to environmental stress. Concentrations of MC greater than 0.2 g/L could reduce the density of solitary cells and colonies, and the colony diameter and extracellular polysaccharide (EPS) content were also decreased. The adsorption of MC to dissolved inorganic phosphorus (DIP) and the cell damage caused by collision may be the main mechanisms underlying this phenomenon. These results elucidate that the treatment with an appropriate concentration of MC may provide an effective mitigation strategy for P. globosa blooms by preventing their growth and colony formation.

Highlights

Accepted: 10 September 2021Phaeocystis globosa, a globally distributed phytoplankton species, is one of the main causes of harmful algal blooms (HABs) and plays an important role in regulating the global climate and the structure of the food web [1,2,3,4]
To identify factors that are involved in Modified clay (MC) controlling P. globosa blooms except flocculation, the effects of MC on P. globosa solitary cell growth, colony formation and colony development were investigated
Treatment could effectively remove P. globosa solitary cells and inhibit their growth, with the inhibition efficiency of the 0.3 g/L MC treatment exceeding 90%. (2) The colony abundances increased under MC concentrations of less than 0.2 g/L

Summary

Introduction

Accepted: 10 September 2021Phaeocystis globosa, a globally distributed phytoplankton species, is one of the main causes of harmful algal blooms (HABs) and plays an important role in regulating the global climate and the structure of the food web [1,2,3,4]. P. globosa has a complex polymorphic lifecycle, alternating between solitary cells and colonial morphotypes. Solitary cells possess two equal heterodynamic flagella and a short haptonema, with a cell diameter of 3–9 μm [5,6]. Colonies are composed of polysaccharides that can form a spherical matrix in which thousands of colonial cells are uniformly embedded, and are able to reach up to 3 cm in diameter [7,8,9]. The formation of colonies is of great biological and ecological importance for the lifecycle of P. globosa. The thin and tough matrix of these colonies provides a defence mechanism against predators, viruses and other unfavorable environmental factors [10,11,12,13,14]

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Results

Discussion

Conclusion