Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel (Prymnesiophyceae) isolated from the South China Sea

• Published in: Chinese Journal of Oceanology and Limnology
• Main Authors: Xu Ning, Huang Bozhu, Hu Zhangxi, Tang Yingzhong, Duan Shunshan, Zhang Chengwu
• Format: Report
• Language: English
• Published: SCIENCE PRESS 2017
• Subjects: Phaeocystis globosa; harmful algal bloom; temperature; salinity; irradiance; growth; Marine & Freshwater Biology; Oceanography; Limnology; NUTRIENT SOURCES; ICE MICROALGAE; MCMURDO SOUND; EUTROPHICATION; COASTAL; PHYTOPLANKTON; DINOPHYCEAE; ANTARCTICA; OCEAN; PHOTOSYNTHESIS; McMurdo Sound; Antarc*; Antarctica
• Online Access: http://ir.ihb.ac.cn/handle/342005/32781; https://doi.org/10.1007/s00343-017-5352-x

Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth of P. globosa (I-s) was 60 mu mol/(m(2)center dot s), which was lower than those of other harmful algal species (70-114 mu mol/(m(2)center dot s)). A moderate growth rate of 0.22/d was observed at 2 mu mol/(m(2)center dot s) (the minimum irradiance in the experiment), and photo-inhibition did not occur at 230 mu mol/(m(2)center dot s) (the maximum irradiance in the experiment). Exposed to 42 different combinations of temperatures (10-31 degrees C) and salinities (10-40) under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24 degrees C and 35, and 27 degrees C and 40. The optimum growth rates (> 0.80/d) were observed at temperatures ranging from 24 to 27 degrees C and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20 degrees C to 31 degrees C and salinities from 20 to 40, it could not grow at temperatures lower than 15 degrees C or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain of P. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year.