Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (6): 1386-1396.DOI: 10.3773/j.issn.1005-264x.2008.06.020

• Original article • Previous Articles     Next Articles


JIANG Zhi-Bing, ZENG Jiang-Ning, CHEN Quan-Zhen(), LIAO Yi-Bo, SHOU Lu, XU Xiao-Qun, LIU Jing-Jing, HUANG Yi-Jun   

  1. Laboratory of Marine Ecosystem and Biogeochemistry, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China
  • Received:2008-04-10 Accepted:2008-06-30 Online:2008-04-10 Published:2008-11-30
  • Contact: CHEN Quan-Zhen


Aims With the drastic increase in number of power plants adjacent to estuaries and bays, damage to plankton caused by thermal shock and chlorination in cooling systems has become a serious ecological problem in coastal areas. Presently, there are no criteria for temperature increment (ΔT) and chlorine dosage (CD) for coastal cooling systems in China. Our objectives are to 1) determine under which Δ T and CD that the phytoplankton biomass has potential to recover after passage through a cooling system and 2) supply a scientific basis for environmental risk assessment and standard formulation of Δ T andCD in cooling water.

Methods In four seasons from August 2006 to May 2007, we collected phytoplankton from the Yueqing Bay. In the laboratory, we stressed the phytoplankton at different Δ T (0, 4, 8, 12 ℃) and CD (0, 1.0, 1.8, 3.2, 5.6 mg·L-1). We then recorded the phytoplankton cell density (PCD) every 24 h in a stable culture for 15 d.

Important findings Both thermal shock and season significantly affected PCD recovery (p<0.001). The recovery period was longer with rising acclimation temperature (AT) and Δ T. When AT was low in spring, autumn and winter, PCD could recover to the control level in 1-6 d at the Δ T of 4-12 ℃. However, thermal shock would affect PCD more severely when AT was high in summer, as 4-9 d was needed for recovery at the Δ T of 4-8 ℃ and the resilience was lost at the Δ T of 12 ℃. Chlorination also significantly affected the PCD recovery (p<0.001) and had a greater impact than thermal shock. ThePCD recovery period was longer with increasing CD. Though PCD could generally restore during 15 d at the CD of 1.0-1.8 mg·L-1, it could not at the CDof 5.6 mg·L-1 in all seasons. Also, there was a synergistic effect between Δ T and CD that the effect of chlorine on PCD recovery was enhanced under temperature increase in the four seasons. Based on these data, current Δ T (6-12 ℃), CD (1-2 mg·L-1) and residual chlorine discharge level (0.15-0.25 mg·L-1) in coastal power plants do not severely affect subtropical phytoplankton biomass.

Key words: thermal shock, chlorine stress, marine phytoplankton, recovery, coastal power plant