College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou, 363000, China; Fujian Province University Key Laboratory of Pollution Monitoring and Control, Minnan Normal University, Zhangzhou, 363000, China.
College of Chemistry, Chemical Engineering & Environmental Science, Minnan Normal University, Zhangzhou, 363000, China.
Chemosphere. 2023 Oct;337:139308. doi: 10.1016/j.chemosphere.2023.139308. Epub 2023 Jun 24.
Human activities, including industrial and agricultural production, as well as domestic sewage discharge, have led to heavy metal pollution and eutrophication in coastal waters. This has caused a deficiency of dissolved inorganic phosphorus (DIP), but an excess dissolved organic phosphorus (DOP) and high concentrations of zinc. However, the impact of high zinc stress and different phosphorus species on primary producers remains unclear. This study examined the impact of different phosphorus species (DIP and DOP) and high zinc stress (1.74 mg L) on the growth and physiology of the marine diatom Thalassiosira weissflogii. The results showed that compared to the low zinc treatment (5 μg L), high zinc stress significantly decreased the net growth of T. weissflogii, but the decline was weaker in the DOP group than in the DIP group. Based on changes in photosynthetic parameters and nutrient concentrations, the study suggests that the growth inhibition of T. weissflogii under high zinc stress was likely due to an increase in cell death caused by zinc toxicity, rather than a decrease in cell growth caused by photosynthesis damage. Nonetheless, T. weissflogii was able to reduce zinc toxicity by antioxidant reactions through enhancing activities of superoxide dismutase and catalase and by cationic complexation through enhancing extracellular polymeric substances, particularly when DOP served as the phosphorus source. Furthermore, DOP had a unique detoxification mechanism by producing marine humic acid, which is conducive to complexing metal cations. These results provide valuable insights into the response of phytoplankton to environmental changes in coastal oceans, particularly the effects of high zinc stress and different phosphorus species on primary producers.
人类活动，包括工农业生产和生活污水排放，导致沿海海域重金属污染和富营养化。这导致溶解无机磷（DIP）缺乏，但溶解有机磷（DOP）和高浓度锌过剩。然而，高锌胁迫和不同磷形态对初级生产者的影响尚不清楚。本研究考察了不同磷形态（DIP 和 DOP）和高锌胁迫（1.74 mg L）对海洋硅藻塔玛斯氏海链藻生长和生理的影响。结果表明，与低锌处理（5 μg L）相比，高锌胁迫显著降低了塔玛斯氏海链藻的净生长，但在 DOP 组的下降幅度小于 DIP 组。基于光合参数和养分浓度的变化，研究表明，高锌胁迫下塔玛斯氏海链藻的生长抑制可能是由于锌毒性导致细胞死亡增加，而不是光合作用损伤导致细胞生长减少。尽管如此，塔玛斯氏海链藻能够通过抗氧化反应增强超氧化物歧化酶和过氧化氢酶的活性，以及通过增强细胞外聚合物物质（特别是当 DOP 作为磷源时）的阳离子络合作用，来减轻锌毒性。此外，DOP 通过产生海洋腐殖酸具有独特的解毒机制，有利于与金属阳离子络合。这些结果为了解沿海海洋中浮游植物对环境变化的响应提供了有价值的信息，特别是高锌胁迫和不同磷形态对初级生产者的影响。
