The proliferation of sea lice (Lepeophtheirus salmonis) represents a major challenge for the salmonid aquaculture industry in Norway. Hydrogen peroxide (H₂O₂) is a chemotherapeutant frequently used on Norwegian farms, however, its toxicity to non-target benthic species and habitats remains poorly understood. Maerl beds are constructed by the accumulation of non-geniculate coralline algae and provide important ecological functions. Due to the rapid expansion of aquaculture in Norway and the continued use of H₂O₂ as an anti-sea lice treatment, it is crucial to understand the impact of H₂O₂ on the physiology of maerl-forming species. The effects of a 1 h exposure to H₂O₂ on the photophysiology and bleaching of the coralline alga Lithothamnion soriferum were examined here through a controlled time-course experiment. PAM fluorimetry measurements showed that H₂O₂ concentrations ≥ 200 mg l⁻¹ negatively affected photosystem II (PSII) in thalli immediately after exposure, which was observed through a significant decline in maximum photochemical efficiency (F_v/F_m) and relative electron transport rate (rETR). The negative effects on PSII induced by oxidative stress, however, appear to be reversible, and full recovery of photosynthetic characteristics was observed 48 h to 28 days after exposure to 200 mg H₂O₂ l⁻¹ and 2000 mg H₂O₂ l⁻¹, respectively. At 28 days after exposure, there was evidence of two- to four-times more bleaching in thalli treated with concentrations ≥ 200 mg H₂O₂ l⁻¹ compared to those in the control. This indicates that despite the recovery of PSII, persistent damages can occur on the structural integrity of thalli, which may considerably increase the vulnerability of coralline algae to further exposure to H₂O₂ and other chemical effluents from salmonid farms.

海虱（Lepeophtheirus Salmonis）的繁殖是挪威鲑鱼养殖业面临的主要挑战。过氧化氢 (H ₂ O ₂ ) 是挪威农场经常使用的化学治疗剂，然而，它对非目标底栖物种和栖息地的毒性仍然知之甚少。Maerl 床由非膝状珊瑚藻的积累构成，具有重要的生态功能。由于挪威水产养殖业的迅速扩张以及继续使用 H ₂ O ₂作为抗海虱处理方法，了解 H ₂ O _{2的影响至关重要}关于成矿物种的生理学。在此通过受控的时间过程实验检查了 1 小时暴露于 H ₂ O ₂对珊瑚藻Lithothamnion soriferum的光生理学和漂白的影响。PAM 荧光测定法测量表明，H ₂ O ₂浓度 ≥ 200 mg l ^-1在暴露后立即对菌体中的光系统 II (PSII) 产生负面影响，这是通过最大光化学效率 (F _v /F _m) 和相对电子传输速率 (rETR)。然而，氧化应激对 PSII 的负面影响似乎是可逆的，并且在暴露于 200 mg H ₂ O ₂ l ^-1和 2000 mg H ₂ O ₂ l后 48 小时至 28 天观察到光合特性的完全恢复^-1，分别。_{在暴露后 28 天，有证据表明，用浓度 ≥ 200 mg H 2} O ₂ l ^-1处理的菌体中的漂白增加了 2 到 4 倍与对照组相比。这表明尽管 PSII 恢复了，但菌体的结构完整性可能会发生持续性损害，这可能会大大增加珊瑚藻进一步暴露于鲑鱼养殖场的 H ₂ O ₂和其他化学流出物的脆弱性。