The impact of elevated atmospheric CO2 on cadmium toxicity in Pyropia haitanensis (Rhodophyta)

• Published in: Environmental science and pollution research international 2018-11, Vol.25 (33), p.33361-33369
• Main Authors: Ma, Haiying, Zou, Dinghui, Wen, Jiayi, Ji, Zhiwei, Gong, Jingyu, Liu, Chunxiang
• Format: Article
• Language: English
• Subjects: Acidification; Algae; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Cadmium; Carbon dioxide; Chemical evolution; Coastal waters; Earth and Environmental Science; Ecotoxicology; Electron transport; Environment; Environmental Chemistry; Environmental Health; Environmental science; Growth rate; Heavy metals; Irradiance; Ocean acidification; Photosynthesis; Physiology; Pyropia haitanensis; Research Article; Rhodophyta; Seaweeds; Superoxide dismutase; Thalli; Toxicity; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-018-3289-z

Cadmium is one of the major heavy metal pollutions in coastal waters, and it is well known that cadmium at trace concentration is toxic to macroalgae. Change in marine carbonate system and ocean acidification caused by elevated atmospheric CO 2 also alter physiological characteristics of macroalgae. However, less research is focused on the combined impacts of elevated CO 2 and cadmium pollution on the growth and physiology in macroalgae. In this study, the maricultivated macroalga Pyropia haitanensis (Rhodophyta) was cultured at three levels of Cd 2+ (control, 4 and 12 mg L −1 ) and two concentrations of CO 2 , the ambient CO 2 (AC, 410 ppm) and elevated CO 2 (HC, 1100 ppm). The results showed that 12 mg L −1 Cd 2+ significantly suppressed the relative growth rate and superoxide dismutase activity in AC-grown P. haitanensis , while such inhibition extents by Cd 2+ were alleviated in HC-grown algae. Cd 2+ had no effects on efficiency of electron transport (α) and maximum electron transport rate (ETR max ), but α was increased by elevated CO 2 . Cd 2+ dramatically suppressed the maximum net photosynthesis oxygen evolution rate (NPR m ) and the minimum saturation irradiance (I k ) when the algal thalli were grown at AC, while such suppression of NPR m by Cd 2+ was much decreased when the thalli were grown at HC. Collectively, our results suggested that elevated CO 2 would alleviate Cd 2+ toxicity on P. haitanensis .