Graduate School of Science and Engineering, Ibaraki University, Hitachi, Ibaraki, 316-8511, Japan.
Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Abiko, Chiba, 270-1194, Japan.
Environ Pollut. 2022 Sep 1;308:119676. doi: 10.1016/j.envpol.2022.119676. Epub 2022 Jun 23.
Changes in natural estuarine environment and anthropogenic disturbances are becoming significant threats to organisms, particularly bivalves. A deeper understanding of the relationship between biochemical- and individual-level responses is necessary to assess the combined effects of natural and anthropogenic factors on bivalves. To the best of our knowledge, this is the first study where the oxygen radical absorbance capacity (ORAC) and carbon-based scope for growth (C-SFG) were applied as biomarkers to evaluate the response of the brackish water clam Corbicula japonica to four spatiotemporally varying environmental factors. High water temperature and food availability supported C-SFG while high salinity inhibited it. Most of wastewater (WW) treatments resulted in negative C-SFG values because of a reduced clearance rate and increased excretion rate. In particular, high food availability with WW treatment resulted in the lowest C-SFG value of -114 μg C·ind h. The ORAC was activated in response to high salinity with WW treatment (p < 0.05). To ascertain the combined effects of the natural and anthropogenic factors, principal component and cluster analyses were performed on the ORAC and C-SFG data. Anthropogenic WW was found to have different effects on the physiological and biochemical biomarkers according to the natural conditions. A roughly negative correlation was observed between ORAC and C-SFG because activation of the antioxidant capacity can influence the growth potential of the clams through the additional use of available metabolic energy. However, some exceptions were observed where both the ORAC and C-SFG values were either high or low, which could be because the C-SFG response varies depending on different metabolic behaviors even when the ORAC response remains the same. These results indicate that the biochemical-level response (i.e., ORAC) of C. japonica can be interpreted using individual-level response (i.e., C-SFG), but careful attention must be given to over- or underestimation.
自然河口环境变化和人为干扰正成为生物，特别是双壳类动物的重大威胁。为了评估自然和人为因素对双壳类动物的综合影响，我们需要更深入地了解生物化学和个体水平响应之间的关系。据我们所知，这是首次应用氧自由基吸收能力（ORAC）和基于碳的生长范围（C-SFG）作为生物标志物来评估咸水蛤蜊日本沼虾对四个时空变化的环境因素的响应。高水温和丰富的食物支持 C-SFG，而高盐度则抑制它。大多数废水（WW）处理由于清除率降低和排泄率增加而导致负的 C-SFG 值。特别是，高食物可用性与 WW 处理导致最低的 C-SFG 值为-114μg C·ind·h。ORAC 在高盐度和 WW 处理的刺激下被激活（p<0.05）。为了确定自然和人为因素的综合影响，对 ORAC 和 C-SFG 数据进行了主成分和聚类分析。根据自然条件，发现人为 WW 对生理和生化生物标志物有不同的影响。ORAC 和 C-SFG 之间观察到大致负相关，因为抗氧化能力的激活可以通过额外利用可用代谢能量来影响蛤蜊的生长潜力。然而，也观察到一些例外情况，ORAC 和 C-SFG 值都很高或都很低，这可能是因为 C-SFG 响应取决于不同的代谢行为，即使 ORAC 响应保持不变。这些结果表明，C. japonica 的生化水平响应（即 ORAC）可以用个体水平响应（即 C-SFG）来解释，但必须注意过度或低估。
