Vidal Tânia, Marques Catarina, Abrantes Nelson, Pereira Joana Luísa, Soares Amadeu M V M, Gonçalves Fernando
Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal,
Environ Sci Pollut Res Int. 2015 Apr;22(8):5919-30. doi: 10.1007/s11356-014-3713-y. Epub 2014 Oct 30.
The availability of rapid and effective methodologies for assessing lotic systems with microphytobenthos is still quite scarce. Hence, the primary goal of this study was to optimize the growth conditions of the sensitive and ubiquous benthic diatom Navicula libonensis for laboratorial and field assessments. The effect of different conditions of temperature, photoperiod, initial cell density, test duration and cell encapsulation into calcium alginate beads was evaluated in a first set of experiments. There was a slight increase in the growth of free and immobilized cells at 23 °C, at lower initial cell densities and at the shortest experimental period (6 days). Through all the conditions, the growth profiles of free versus immobilized were fairly variable. A second experimental trial involved the validation of selected conditions, applied to the ecotoxicological testing of N. libonensis to two reference chemicals-3,5-dichlorophenol and potassium dichromate. A similar response of free and immobilized cells was observed between exposures to spiked stream water and synthetic medium, and through the conditions tested. This outcome suggests that N. libonensis may potentially provide reliable responses under direct in situ exposures.
用于评估含有微型底栖藻类的流水系统的快速有效方法仍然非常匮乏。因此，本研究的主要目标是优化敏感且分布广泛的底栖硅藻利博舟形藻（Navicula libonensis）的生长条件，以用于实验室和现场评估。在第一组实验中，评估了温度、光周期、初始细胞密度、试验持续时间以及将细胞封装到海藻酸钙珠中的不同条件的影响。在23°C、较低的初始细胞密度和最短的实验周期（6天）下，游离细胞和固定化细胞的生长略有增加。在所有条件下，游离细胞与固定化细胞的生长曲线差异较大。第二项实验涉及对选定条件的验证，将其应用于利博舟形藻对两种参考化学品——3,5-二氯苯酚和重铬酸钾的生态毒理学测试。在暴露于加标溪水和合成培养基以及所测试的条件下，观察到游离细胞和固定化细胞有类似的反应。这一结果表明，利博舟形藻在直接原位暴露下可能会提供可靠的反应。
