Marine Ecology Laboratory, Department of Life Sciences, Presidency University, 86/1, College Street, Kolkata 700073, India.
Marine Ecology Laboratory, Department of Life Sciences, Presidency University, 86/1, College Street, Kolkata 700073, India.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111549. doi: 10.1016/j.ecoenv.2020.111549. Epub 2020 Nov 3.
Meiobenthos has been considered as an excellent tool for biomonitoring assessment. Elevated temperature and oil pollution are considered as the most pervasive aspects of global environmental changes and matter of concern for contemporary society. Presently, very limited information is available about the synergistic effect of these stressors on meiobenthic community structure and tolerance potential from tropical intertidal environment. Here, we assessed their impacts on meiobenthic community by conducting a 60 days long benthocosm experiment selecting three sets of temperature (25°, 30° and 35 °C) and two sets of diesel oil (low and high) combinations. Gradual changes in their community composition were revealed discernibly with exposures to both the disturbances after 30 and 60 days of experimental period. Diversity profiles for the nematodes were less affected, but copepods showed a graded response of decreasing density with increasing dose of both the stressors. Other meiobenthic taxa such as halacarid mite, turbellaria and polycheate juveniles were adversely affected and eliminated from the treatments, howbeit abundance of ostracods, foraminiferans and bivalve settlers varied significantly. A 3-factor PERMANOVA indicated a significant effect of temperature, diesel, between their interaction and interaction among stressors and time on meiofaunal abundances. In case of free-living nematodes, temperature rise and diesel contamination synchronously led to an elimination of k-selected species like Halalaimus gracilis, H. longicaudatus, Oxystomina aesetosa and Pomponema sp. with a significant decrease in abundance of H. capitulatus and Oncholaimus sp. The r-selected species Daptonema invagiferoum, Sabatieria praedatrix, Theristus acer, Monhystera sp. and Thalassomonhystera sp. had endured even at high doses of diesel treatment in three different temperatures set up. The effects were evident in term of changes in life strategies with an increment of opportunistic species and increased trophic diversity of deposit feeders in treated sediments. Overall, elevated temperature together with diesel oil contamination were found to alter species dynamics within shallow intertidal meiobenthic communities, which might have significant Armageddon on benthic ecosystem functioning.
底栖微型生物一直被认为是生物监测评估的一个极好工具。升高的温度和石油污染被认为是全球环境变化最普遍的方面，也是当代社会关注的问题。目前，关于这些胁迫因素对热带潮间带环境中底栖微型生物群落结构和耐受潜力的协同作用，我们所掌握的信息非常有限。在这里，我们通过进行为期 60 天的底栖生物共生实验，选择三组温度（25°C、30°C 和 35°C）和两组柴油（低和高）组合，评估了它们对底栖微型生物群落的影响。在实验进行 30 天和 60 天后，暴露于两种干扰因素后，明显揭示了它们群落组成的逐渐变化。线虫的多样性特征受影响较小，但桡足类的密度随着两种胁迫因素剂量的增加呈梯度下降。其他底栖微型生物类群，如卤虫螨、扁形动物和多毛类幼体受到不利影响，并从处理中消除，但介形类动物、有孔虫类和双壳类定居者的丰度变化显著。一个三因子 PERMANOVA 表明，温度、柴油、它们之间的相互作用以及胁迫因素和时间对小型底栖动物丰度的显著影响。对于自由生活的线虫，温度升高和柴油污染同步导致了选择压力较低的物种如 Halalaimus gracilis、H. longicaudatus、Oxystomina aesetosa 和 Pomponema sp. 的消除，H. capitulatus 和 Oncholaimus sp. 的丰度显著减少。选择压力较高的物种 Daptonema invagiferoum、Sabatieria praedatrix、Theristus acer、Monhystera sp. 和 Thalassomonhystera sp. 即使在三种不同温度设置下的高剂量柴油处理中也能存活。这种影响表现在生活策略的变化上，即在处理沉积物中，机会主义物种增加，食沉积物动物的营养多样性增加。总的来说，升高的温度与柴油污染一起，被发现改变了浅潮间带底栖微型生物群落内的物种动态，这可能对底栖生态系统功能产生重大影响。
