Organophosphorus (OP) is bioavailable to phytoplankton with photolysis can play an important role in the process. The photolysis behaviour of an OP (adenosine 5′-monophosphate, AMP) in seawater was investigated, and AMP can release inorganic phosphate under environmentally relevant light conditions, indicating OP photodegradation might be important in the phosphorus biogeochemical cycle. The results are helpful to further understand the bioavailability and cycle of OP in marine environment.

Organic phosphorus (OP) is a potential source of bioavailable phosphorus for phytoplankton through photolysis and other degradation processes. Therefore, OP photodegradation plays an important role in phosphorus biogeochemical cycle.

Taking adenosine 5′-monophosphate (AMP) as a model OP, we investigated the photolysis behaviour in seawater and discussed the mechanism. The photolysis dynamics were studied based on the inorganic phosphorus production at appropriate time intervals, which was analysed by spectrophotometric molybdenum blue method. The effects of medium, light and radicals were investigated.

It was found that AMP can release inorganic phosphate under photosynthetically active radiation and ultraviolet (UV) with UVB being the most reactive band. The degradation of AMP in seawater was lower than that in deionised water under the same conditions, and the fresh seawater was more beneficial than aged seawater. The kinetics could be described by a pseudo-first order equation. Fe³⁺ can promote the photolysis due to the generation of ·OH radicals, while within the range of this study, changes of Fe³⁺ content have no substantial effect on the promotion. The influence of ethanol and tetrahydrofuran as radical inhibitor showed evident inhabitation to the degradation, indicating that ·OH and ¹O₂ played an important role in the process, and ·OH seemed more important than ¹O₂.

OP photodegradation is of importance in the phosphorus biogeochemical cycle. Varying properties of the medium and light can affect the OP transformation in seawater. The results are helpful to further understand the bioavailability and cycle of OP in the marine environment.

有机磷（OP）可被浮游植物生物利用，光解作用在此过程中发挥重要作用。研究了 OP（5′-单磷酸腺苷，AMP）在海水中的光解行为，AMP 在环境相关光照条件下可以释放无机磷酸盐，表明 OP 光降解可能在磷生物地球化学循环中发挥重要作用。研究结果有助于进一步了解OP在海洋环境中的生物利用度和循环。

有机磷（OP）是浮游植物通过光解和其他降解过程生物可利用磷的潜在来源。因此，OP光降解在磷生物地球化学循环中发挥着重要作用。

以5′-单磷酸腺苷（AMP）为模型OP，研究了海水中的光解行为并讨论了其机理。根据适当时间间隔产生的无机磷来研究光解动力学，并通过分光光度钼蓝法进行分析。研究了介质、光和自由基的影响。

研究发现，AMP在光合有效辐射和紫外线（UV）的作用下可以释放无机磷酸盐，其中UVB是最活跃的波段。相同条件下，海水中AMP的降解低于去离子水，新鲜海水比陈化海水更有利。动力学可以用伪一级方程来描述。Fe ³⁺因产生·OH自由基而促进光解，而在本研究范围内，Fe ³⁺含量的变化对其促进作用没有实质性影响。乙醇和四氢呋喃作为自由基抑制剂的影响对降解表现出明显的抑制作用，表明·OH和¹ O ₂在该过程中发挥了重要作用，并且·OH似乎比¹ O ₂更重要。

OP 光降解在磷生物地球化学循环中非常重要。介质和光的不同特性会影响海水中OP的转化。研究结果有助于进一步了解OP在海洋环境中的生物利用度和循环。