In this paper, we propose a stochastic phytoplankton–zooplankton system considering phytoplankton defensive and zooplankton offensive effects. The aim of this paper is to study the effects of environmental fluctuations on plankton population dynamics. We prove the existence, uniqueness and stochastically ultimately boundedness of global positive solutions, and the extinction and persistence in the mean of plankton populations. When the system is persistent in the mean, there exists a unique stationary distribution. To further investigate the dynamics of the stochastic plankton system, we perform some numerical simulations and find that the white noise can directly affect the survival of plankton populations. The phytoplankton defense can strengthen the capability of phytoplankton protection that will benefit the plankton survival and weaken the impact of environmental fluctuations, but it has a negative effect on zooplankton population. Our findings reveal that zooplankton offense is beneficial to the survival of phytoplankton but may threaten the persistence of zooplankton population. An appropriate increase of phytoplankton defense or decrease of zooplankton offense can potentially change the survival state of the plankton system.

在本文中，我们提出了考虑浮游植物防御和浮游动物进攻效应的随机浮游植物-浮游动物系统。本文的目的是研究环境波动对浮游生物种群动态的影响。我们证明了全局正解的存在性、唯一性和随机最终有界性，以及浮游生物种群平均值的灭绝和持续性。当系统均值持续存在时，存在唯一的平稳分布。为了进一步研究随机浮游生物系统的动力学，我们进行了一些数值模拟，发现白噪声可以直接影响浮游生物种群的生存。浮游植物防御可以增强浮游植物的保护能力，有利于浮游生物的生存，减弱环境波动的影响，但对浮游动物种群有负面影响。我们的研究结果表明，浮游动物的进攻有利于浮游植物的生存，但可能威胁浮游动物种群的持续存在。适当增加浮游植物防御或减少浮游动物进攻可能会改变浮游生物系统的生存状态。