Department of Biology, Faculty of Science, Istanbul University, 34134, Vezneciler, Istanbul, Turkey; International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco.
International Atomic Energy Agency, Environment Laboratories, 4a Quai Antoine 1er, MC-98000, Principality of Monaco, 98000, Monaco.
Chemosphere. 2020 Jul;250:126314. doi: 10.1016/j.chemosphere.2020.126314. Epub 2020 Feb 24.
The dissolved oxygen concentration of the world's oceans has systematically declined by 2% over the past 50 years, and there has been a notable commensurate expansion of the global oxygen minimum zones (OMZs). Such wide-scale ocean deoxygenation affects the distribution of biological communities, impacts the physiology of organisms that may affect their capacity to absorb and process contaminants. Therefore, the bioaccumulation efficiencies of three contrasting radionuclides, Ag, Cs and Zn were investigated using controlled aquaria in the blue mussel Mytilus edulis under three contrasting dissolved oxygen regimes: normoxic; 7.14 mg L, reduced oxygen; 3.57 mg L and hypoxic 1.78 mg L conditions. Results indicated that hypoxic conditions diminished Ag uptake in the mussel, whereas depuration rates were not affected. Similarly, hypoxia appeared to cause a decrease in the Zn bioaccumulation rate, as evidenced by both weakened uptake and rapid elimination rates. Effects of hypoxia on the metabolome of mussels were also explored by untargeted Nuclear Magnetic Resonance (NMR) spectroscopic methods. The metabolic response was characterised by significantly greater abundance of several amino acids, amino sulfonic acids, dicarboxylic acids, carbohydrates and other metabolites in the lowest oxygen treatment, as compared to the higher oxygen treatments. Clearance rates significantly dropped in hypoxic conditions compared to normoxia. Results suggest that hypoxic conditions, and even partly moderate hypoxia, alter ventilation, an-aerobic, oxidative and osmoregulation metabolism of this mussel, which may further influence the trace element bioaccumulation capacity.
在过去的 50 年中，全球海洋的溶解氧浓度系统地下降了 2%，并且全球氧气最小区（OMZ）明显扩大。这种大规模的海洋脱氧作用影响生物群落的分布，影响可能影响其吸收和处理污染物能力的生物体的生理学。因此，使用三种不同的溶解氧条件下的贻贝 Mytilus edulis 控制水族箱，研究了三种对比放射性核素 Ag、Cs 和 Zn 的生物累积效率：正常氧；7.14 mg/L、低氧；3.57 mg/L 和缺氧 1.78 mg/L。结果表明，缺氧条件降低了贻贝对 Ag 的吸收，而净化率不受影响。同样，缺氧似乎导致 Zn 的生物累积率降低，这表现在摄取和快速消除率都减弱。还通过非靶向性核磁共振（NMR）光谱方法探索了缺氧对贻贝代谢组的影响。代谢反应的特征是在最低氧处理中，几种氨基酸、氨基酸磺酸、二羧酸、碳水化合物和其他代谢物的丰度明显更高，与较高氧处理相比。在缺氧条件下，清除率明显下降。结果表明，缺氧条件，甚至部分中度缺氧，改变了这种贻贝的通气、无氧、氧化和渗透压调节代谢，这可能进一步影响微量元素的生物累积能力。
