Jianjun Cui, Baohua Zhang, Chunli Chen, Xinlu Wu, Manning Lei, Zhaojun Zeng, Kun Lin, Cunxi Fang, Jinyi Wu, Enyi Xie, Wenrong Zhu, Xiao Jiang, Hui Guo, Alvin P. Monotilla
Owing to its high toxicity, recalcitrance, and bioaccumulation potential, heavy metal cadmium (Cd) bioaccumulates through the food chain and threatens the stability of aquatic ecosystems and human health. It poses a challenge in current aquatic environmental remediation. Against the backdrop of global warming, high-temperature-tolerant macroalgae-based bioremediation technologies have potential for treating aquaculture effluents. Here, Gracilariopsis heteroclada , a characteristic high-temperature-tolerant species in southern China, was selected as the research object. Physiological experiments with gradient Cd²+ concentrations were designed to study the growth and physiological response mechanisms and tolerance thresholds of G. heteroclada to Cd, while quantifying its Cd biosorption capacity. The results showed that Cd concentrations ≥ 0.5 mg/L significantly inhibited algal growth, with the growth rate decreasing to −0.14%/d at 10 mg/L. Elevated cadmium levels also markedly affected photosynthetic pigment contents and chlorophyll fluorescence parameters, with the initial concentrations causing significant inhibition being 0.5, 1, 7, and 7 mg/L for Chl a, Car, PE, and PC, respectively. In addition, G. heteroclada exhibited strong cadmium purification capacity, achieving a maximum adsorption rate of 3904.87 µg/(g·h) and removal efficiencies exceeding 40% after 72 h of treatment. In summary, G. heteroclada shows strong potential for cadmium remediation and biomonitoring in aquaculture systems, providing practical implications for sustainable aquaculture and the effective utilization of red algal resources. © 2026 The Authors.
Fisheries College of Guangdong Ocean University, Key Laboratory of Marine Ecology and Aquaculture Environment of Zhanjiang, Zhanjiang, 524088, China; Xuwen Seaweed Development Co., Ltd., Xiangshan, Zhejiang, Ningbo, 315000, China; South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Department of Biology, University of San Carlos, Cebu, 6000, Philippines
