Population dynamics and reproduction of the heterotrophic dinoflagellate Noctiluca scintillans in Jiaozhou Bay, China

Abstract

Outbreaks of the heterotrophic dinoflagellate Noctiluca scintillans have impacted the Chinese coastal ecosystem for decades; however, which and how environmental factors affect its reproductive pattern and further influence its population dynamics remain to be investigated. From January 2019 to January 2020, 9 cruises were conducted at 12 stations in Jiaozhou Bay, China. The different life stages of N. scintillans were distinguished and quantified with the assistance of microscopic observation and quantitative real-time PCR (qRT-PCR). N. scintillans was seasonally abundant in winter-spring and September, but depleted in summer and October. The asexual reproduction of N. scintillans, which appeared as binary fission, mainly occurred in colder water (<11°C), and could be the major mode of reproduction driving population growth in March-April. In September, even though the asexual mode is by this time restricted by high water temperatures (>26°C), N. scintillans blooms still occurred with the assistance of sexual reproduction and the potential coupling effect of a favorable food source and physical environment, in which chain-forming diatoms were dominant in the phytoplankton community and gametes could be accumulated by continuous mild southeast winds and rainless weather. The present study contributes to a better understanding of the life cycle of N. scintillans in natural seawaters and provides valuable information to assess the variation in the abundance of gametes.

Long‐term changes in Noctiluca scintillans blooms along the Chinese coast from 1933 to 2020

“…Generally speaking, the spatial distribution may be related to regional environmental characteristics including temperature, salinity, topography, hydrologic conditions, and nutrients. Researches had shown that suitable hydrologic conditions are beneficial to the rapid increase in the local cell density of N. scintillans (Fevre & Grall, 1970; Huang & Qi, 1997; Zhang et al, 2022). Among Chinese coastal provinces, Guangdong and Fujian have the longer coastline, numerous islands, and bays, which can reduce the disturbance of strong currents and winds and provide favorable conditions for the occurrence of N. scintillans blooms.…”

“…Researches had shown that suitable hydrologic conditions are beneficial to the rapid increase in the local cell density of N. scintillans (Fevre & Grall, 1970;Zhang et al, 2022). Among Generally, HABs are usually driven by several factors, nutrients (or foods) are only the material basis, but not the decisive factor (Wang, Wu, et al, 2020).…”

Interactions between Noctiluca scintillans and Three Co-Occurring Microalgae in Response to Varying Nutrient Levels

“…In addition to its role in the regulation of carbon transfer within marine food webs, N. scintillans also serves as a crucial factor for nutrient regeneration [13,24]. This organism can accumulate and regenerate substantial quantities of dissolved nutrients (e.g., NH 4 + and PO 4 3− ) and organic substances [23,25,26].…”