| As an important component of Marine primary productivity, the process of arsenic absorption and conversion by microalgae is crucial for maintaining the balance of Marine ecosystems. At the same time, because arsenic is passed along the food chain, it also poses a certain threat to human health. Due to the large amount of input of terrestrial and dry and wet deposition nitrogen, the N/P ratio ratio in the ocean is seriously unbalanced, but the effect of the change of the N/P ratio on the uptake and conversion of arsenic by marine microalgae is still unclear. The effect of N/P ratio on the absorption and conversion of arsenate (AsV) was studied. By measuring cell growth, chlorophyll fluorescence parameters, intracellular arsenic content, arsenic form and enzymes related to arsenic absorption and transport, the physiological response and arsenic metabolism mechanism of Dunaliella salina were investigated. The results showed that the N/P ratio had a significant effect on the absorption and conversion of AsV. Under the condition of high phosphorus, the conversion of inorganic arsenic to organic arsenic can be promoted by increasing nitrogen concentration appropriately. Under the condition of low phosphorus, increasing nitrogen concentration promoted the absorption and conversion of As by Dunaliella salina. When the N/P ratio was 10, the arsenic conversion degree of Dunaliella salina was the highest, and the organic arsenic content accounted for 96.7%. The results of this study provide an important reference for understanding the biogeochemical cycle of arsenic in marine ecosystems and evaluating the ecological and health risks of arsenic in marine ecosystems. |