Mangroves are increasingly used as biofiltering systems of (pre-treated) domestic effluents. However, these wastewater discharges may affect local macrofauna. This laboratory study investigates the effects of wastewater exposure on the mangrove spider crab Neosarmatium meinerti, a key engineering species which is known to be affected by waste waters in effluent-impacted areas. These effects were quantified by monitoring biological markers of physiological state, namely oxygen consumption, the branchial cavity ventilation rate, gill physiology and morphology, and osmoregulatory and redox balance. Adults acclimated to clean seawater (SW, 32 ppt) and freshwater (FW, ∼0 ppt) were compared to crabs exposed to wastewater for 5 h (WW, ∼0 ppt). Spider crabs exposed to WW increased their ventilation and whole-animal respiration rates by 2- and 3-fold respectively, while isolated gill respiration increased in the animals exposed to FW (from 0.5 to 2.3 and 1.1 nmol O₂ min⁻¹ mg DW⁻¹ for anterior and posterior gills, respectively) but was not modified in WW-exposed individuals. WW exposure also impaired crab osmoregulatory capacity; an 80 mOsm kg⁻¹ decrease was observed compared to FW, likely due to decreased branchial NKA activity. ROS production (DCF fluorescence in hemolymph), antioxidant defenses (superoxide dismutase and catalase activities) and oxidative damage (malondialdehyde concentration) responses varied according to animal gender. Overall, this study demonstrates that specific physiological parameters must be considered when focusing on crabs with bimodal breathing capacities. We conclude that spider crabs exposed to WW face osmoregulatory imbalances due to functional and morphological gill remodeling, which must rapidly exhaust energy reserves. These physiological disruptions could explain the ecological changes observed in the field.

红树林被越来越多地用作（预处理的）生活污水的生物过滤系统。但是，这些废水的排放可能会影响当地的大型动物。这项实验室研究调查了废水暴露对红树林蜘蛛蟹Neosarmatium meinerti的影响，是一种关键工程物种，已知会受到污水影响地区的废水的影响。通过监测生理状态的生物标志物，即耗氧量，cavity腔通气率，g的生理学和形态学以及渗透压和氧化还原平衡，可以量化这些影响。将适应清洁海水（SW，32 ppt）和淡水（FW，〜0 ppt）的成年动物与暴露于废水5小时（WW，〜0 ppt）的螃蟹进行比较。暴露于WW蜘蛛蟹增加了它们的通风和整体动物呼吸速率由2-和分别3倍，而分离的鳃呼吸暴露于FW（从0.5动物增加至2.3和1.1纳摩尔ö ₂分钟^-1 毫克DW ^{- 1个}分别用于前g和后g），但在暴露于WW的个体中未进行任何修改。WW暴露也损害了蟹的渗透调节能力。80 mOsm千克^-1与FW相比观察到的减少，可能是由于分支NKA活性降低。ROS的产生（血淋巴中的DCF荧光），抗氧化剂的防御作用（超氧化物歧化酶和过氧化氢酶活性）和氧化损伤（丙二醛浓度）的响应因动物性别而异。总的来说，这项研究表明，在关注具有双峰呼吸能力的螃蟹时，必须考虑特定的生理参数。我们得出的结论是，暴露于WW的蜘蛛蟹由于功能和形态的g重塑而面临渗透调节失衡，必须迅速耗尽能量储备。这些生理上的破坏可以解释在田间观察到的生态变化。