Response of growth and development of the Pacific oyster (Crassostrea gigas) to thermal discharge from a nuclear power plant

Abstract

Background: During electricity generation of nuclear power plant, heat energy cannot be completely converted into electrical energy, and a part of it is lost in the form of thermal discharge into the environment. The thermal discharge is harmful to flora and fauna leading to environmental deterioration, biological diversity decline, and even biological extinction.

Results: The present study investigated the influence of thermal discharge from a nuclear power plant on the growth and development of Pacific oyster Crassostrea gigas which is widely used as bio indicator to monitor environmental changes. The growth of soft part and the gonad development of oysters were inhibited due to thermal discharge. During winter season, temperature elevation caused by thermal discharge promoted the growth of oyster shells. During summer season, the growth rate of oysters in thermal discharge area was significantly lower than that of the natural sea area.

Conclusions: The results of this study provided a better understanding of assessing the impact of thermal discharge on the marine ecological environment and mariculture industry. It also provided a scientific basis for defining a safe zone for aquaculture in the vicinity of nuclear power plants.

Keywords: Crassostrea gigas; Growth and development; Nuclear power plant; Thermal discharge.

Fig. 1

Study area and sample stations in Haizhou Bay

Fig. 2

Diagram showing method of measuring the height, length, and width of oyster valves

Fig. 3

Variation of temperature at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 4

Variation of SH at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 5

Variation of SL at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 6

Variation of SW at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 7

Variation of MY at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 8

Variation of GSI at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 9

Variation in phytoplankton density at sample stations. Different letters of the same sampling date indicate significant difference at 0.05

Fig. 10

The growth rate of oyster after March 18, 2016. Different letters of the same index indicate significant difference at 0.05