Cell density-dependent suppression on the development and photosynthetic activities of Sargassum fusiformis embryos by dinoflagellate Karenia mikimotoi

Tiange Shang; Lidong Lin; Binbin Chen; Min Wang; Wenli Qin; Chuanjun Dai; Hengguo Yu; Jun Li; Ronald W Thring; Zengling Ma; Min Zhao

doi:10.1016/j.hal.2020.101842

Cell density-dependent suppression on the development and photosynthetic activities of Sargassum fusiformis embryos by dinoflagellate Karenia mikimotoi

Harmful Algae. 2020 Jun:96:101842. doi: 10.1016/j.hal.2020.101842. Epub 2020 Jun 11.

Authors

Tiange Shang¹, Lidong Lin², Binbin Chen¹, Min Wang¹, Wenli Qin¹, Chuanjun Dai¹, Hengguo Yu¹, Jun Li¹, Ronald W Thring³, Zengling Ma⁴, Min Zhao⁵

Affiliations

¹ Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China; National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China.
² Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China; Dongtou Fisheries Science and Technology Research Institute, Dongtou, Wenzhou 325700, China.
³ Environmental Science and Engineering, University of Northern British Columbia, Prince George, British Columbia V2N4Z9, Canada.
⁴ Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China; National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China. Electronic address: mazengling@wzu.edu.cn.
⁵ Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China; National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China. Electronic address: zhaomin-zmcn@tom.com.

PMID: 32560840
DOI: 10.1016/j.hal.2020.101842

Abstract

Lots of research has demonstrated that macroalgae can strongly inhibit the growth of harmful algal bloom (HAB) species in general. However, the effects of HABs or HAB-forming species on macrophytes are still largely uncharacterized until now. In the present study, the effects of the dinoflagellate Karenia mikimotoi cell density gradient, live cell suspension (LC), ruptured cell suspension (RC) as well as the cell-free supernatant (FC) of K. mikimotoi at 1000 μg Chla l^-1 (~1.0 × 10⁵ cells ml^-1) on the development and photosynthesis of Sargassum fusiforme embryos were investigated in a series of laboratory experiments. The results showed that co-cultivation with K. mikimotoi at 500 μg Chla l^-1(~5.0 × 10⁴ cells ml^-1) and higher cell densities significantly (P<0.05) inhibited the development, pigment content and photosynthetic activities of the embryos. In addition, the inhibitory effects increased with increased cell densities and prolonged exposure time. Compared to the embryos cultured with the F/2 medium (Control), exposure to LC, RC and FC of K. mikimotoi at 1000 μg Chla l^-1for 2 weeks all led to decreased relative growth rate (RGR), chlorophyll (Chl) a content, carotenoids (Car) content and photosynthetic activities of the embryos, with LC and RC exhibiting the maximal and the minimal suppression. The dominant inhibitory effects of FC on the embryos indicated that the suppression was mainly caused by the allelochemicals, while the slightest inhibitory effects of RC on the embryos suggested that some intracellular growth-promoting substances were synchronously released when K. mikimotoi cells lyzed. In addition, the most severe growth suppression of embryos by LC indicated that intact cell contact by K. mikimotoi probably also contributed to the inhibitory effects. These results indicated that a dense HAB formed by K. mikimotoi could seriously suppress the development and photosynthesis of S. fusiforme embryos and eventually reduce the seedlings stock.

Keywords: Development; Embryos; Karenia mikimotoi; Morphology; Photosynthesis; Sargassum fusiformis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cell Count
Dinoflagellida*
Harmful Algal Bloom
Photosynthesis
Sargassum*