Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, Bremerhaven 27570, Germany.
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, Bremerhaven 27570, Germany.
Ecotoxicol Environ Saf. 2024 Oct 1;284:116873. doi: 10.1016/j.ecoenv.2024.116873. Epub 2024 Aug 15.
Sessile intertidal organisms live in a harsh environment with challenging environmental conditions and increasing anthropogenic pressure such as microplastic (MP) pollution. This study focused on effects of environmentally relevant MP concentrations on the metabolism of intertidal Pacific oyster Crassostrea gigas, and its potential MP-induced vulnerability to warming during midday low tide. Oysters experienced a simulated semidiurnal tidal cycle based on their natural habitat, and were exposed to a mixture of polystyrene microbeads (4, 7.5 and 10 µm) at two environmentally relevant concentrations (0.025 µg L and 25 µg L) for 16 days, with tissue samplings after 3 and 12 days to address dose-dependent effects over time. On the last day of exposure, the remaining oysters were additionally exposed to low tide warming (3 °C h) to investigate possible MP-induced susceptibility to aerial warming. Metabolites of digestive gland and gill tissues were analysed by using untargeted H nuclear magnetic resonance (NMR) based metabolomics. For the digestive gland metabolite profiles were comparable to each other independent of MP concentration, exposure time, or warming. In contrast, gill metabolites were significantly affected by high MP exposure and warming irrespective of MP, initiating the same cellular stress response to counteract induced oxidative stress. The activated cascade of antioxidant defence mechanisms required energy on top of the general energy turnover to keep up homeostasis, which in turn may lead to subtle, and likely sub-lethal, effects within intertidal oyster populations. Present results underline the importance of examining the effects of environmentally relevant MP concentrations not only alone but in combination with other environmental stressors.
固着潮间带生物生活在一个恶劣的环境中，面临着极具挑战性的环境条件和不断增加的人为压力，如微塑料（MP）污染。本研究重点关注环境相关 MP 浓度对潮间带太平洋牡蛎（Crassostrea gigas）代谢的影响，以及其在中午低潮时对变暖的潜在 MP 诱导脆弱性。牡蛎经历了基于其自然栖息地的模拟半日潮周期，并在两种环境相关浓度（0.025 µg/L 和 25 µg/L）下暴露于聚苯乙烯微珠混合物（4、7.5 和 10 µm）中 16 天，在第 3 天和第 12 天进行组织取样，以研究随时间推移的剂量依赖性影响。在暴露的最后一天，其余的牡蛎还额外暴露于低潮变暖（3°C h），以研究可能的 MP 诱导对空气变暖的敏感性。使用非靶向 H 核磁共振（NMR）基于代谢组学分析消化腺和鳃组织的代谢物。对于消化腺的代谢物图谱，无论 MP 浓度、暴露时间或变暖如何，彼此之间都相似。相比之下，鳃代谢物无论 MP 如何，都受到高 MP 暴露和变暖的显著影响，从而引发相同的细胞应激反应以抵消诱导的氧化应激。抗氧化防御机制的激活级联反应需要在一般能量代谢的基础上额外的能量来维持体内平衡，这反过来又可能导致潮间带牡蛎种群中出现微妙的、可能是亚致死的影响。目前的结果强调了不仅要单独研究环境相关 MP 浓度的影响，还要研究其与其他环境胁迫因素相结合的影响的重要性。
