Titanium dioxide nanoparticles (n-TiO₂) are emerging contaminants and the ecological impact of these materials to the nearshore environment is largely unknown. The reactivity of n-TiO₂ increases with light exposure, and the photocatalytic effects have been shown on cultures of bacteria and microalgae in the laboratory. The purpose of this study was to assess the response of natural bacterial and microalgal communities associated with marine aggregates to n-TiO₂ under conditions similar to those found in the photic zone of nearshore waters. Nano and bulk TiO₂ particles were incorporated into marine aggregates over 4 days under two light conditions: 6:18 and 0:24 (hours light:dark). The abundance and metabolic response of heterotrophic bacteria and viability of microalgae associated with aggregates were assessed. Although the proportion of living microalgae was unchanged, the abundance, total metabolic activity and functional diversity of heterotrophic bacteria were significantly altered by irradiated n-TiO₂.

二氧化钛纳米颗粒（n-TiO ₂）是正在出现的污染物，这些材料对近岸环境的生态影响在很大程度上是未知的。n-TiO ₂的反应性随曝光而增加，并且在实验室中已显示出对细菌和微藻培养物的光催化作用。这项研究的目的是评估与海洋聚集体有关的天然细菌和微藻类群落对n-TiO ₂的响应，其条件类似于在近岸水域光合带中发现的条件。纳米和块状TiO ₂在两种光照条件下（6:18和0:24（小时光照：黑暗）），在4天的时间内将这些颗粒掺入到海洋聚集体中。评估了异养细菌的丰度和代谢反应以及与聚集体相关的微藻的活力。尽管活微藻的比例没有变化，但是通过辐照n-TiO _2可以显着改变异养细菌的丰度，总代谢活性和功能多样性。