Graphene oxide (GO) as a novel and promising material has a huge market and multiple applications. The release of GO into the aquatic system during their life cycle would lead to potential risks for the environment and aquatic organisms. This study evaluated the impacts of GO on algal growth and algal organic matter (AOM) of Microcystis aeruginosa. GO exhibited moderate effects on algal growth and the photosynthetic system. There was no evident influence on cell density and chlorophyll-a content at GO concentrations below 10 mg/L. Variation and characteristics of AOM after the interaction between GO and algae were analyzed. The characteristics of intracellular organic matter on algae’s exposure to GO showed no significant difference compared with the control group. Conversely, GO had greater impacts on extracellular organic matter after the interaction with algae. The dissolved organic carbon and microcystin-LR showed a significant decline with the increasing GO concentration. The overall molecular weight decreased as well, typically for low molecules. Moreover, the three-dimensional fluorescence spectrum showed that the humic acid- or fulvic acid-like organics decreased obviously. These conclusions reflect that GO has a strong adsorption capacity for removing extracellular organic matter, whereas it did not inflict damage to the algal cells, so that little change could be found in intracellular organic matter. The current study is expected to be beneficial in interpreting the potential risks of GO on algal growth and the variation of AOM.

中文翻译：

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氧化石墨烯对铜绿微囊藻藻类有机物的影响

氧化石墨烯（GO）作为一种新颖而有前途的材料，具有巨大的市场和多种应用。GO在其生命周期中释放到水生系统中会导致对环境和水生生物的潜在风险。这项研究评估了GO对铜绿微囊藻的藻类生长和藻类有机质（AOM）的影响。GO对藻类生长和光合系统表现出中等程度的影响。对细胞密度和叶绿素a无明显影响GO浓度低于10 mg / L时的含量 分析了GO与藻类相互作用后AOM的变化和特征。藻类接触GO后细胞内有机质的特征与对照组相比无显着差异。相反，GO与藻类相互作用后对细胞外有机物的影响更大。随着GO浓度的增加，溶解的有机碳和微囊藻毒素-LR显着下降。总体分子量也降低，通常对于低分子而言。而且，三维荧光光谱显示腐殖酸或黄腐酸样有机物明显减少。这些结论表明，GO具有强大的吸附能力，可去除细胞外有机物，而它并未对藻类细胞造成损害，因此细胞内有机物几乎没有变化。预期当前的研究将有助于解释GO对藻类生长和AOM变异的潜在风险。