Department of Biotechnology, Norwegian University of Science and Technology, Sem Sælandsvei 6/8, 7491 Trondheim, Norway.
Water Res. 2010 Oct;44(18):5439-49. doi: 10.1016/j.watres.2010.06.059. Epub 2010 Jul 1.
Transport of ballast water with ships represents a risk for introduction of foreign species. If ballast water is treated during uptake, there will be a recolonization of the ballast water by heterotrophic bacteria during transport. We investigated survival and succession of heterotrophic bacteria after disinfection of seawater in the laboratory, representing a model system of ballast water treatment and transport. The seawater was exposed to ultraviolet (UV) irradiation, ozone (2 doses) or no treatment, incubated for 16 days and examined with culture-dependent and -independent methods. The number of colony-forming units (CFU) was reduced below the detection level after disinfection with UV and high ozone dose (700 mV), and 1% of the initial level for the low ozone dose (400 mV). After less than 3 days, the CFU was back or above the starting point for the control, UV and low ozone treatment, whereas it took slightly more than 6 days for the high ozone treatment. Disinfection increased substrate availability and reduced cell densities. Lack of competition and predation induced the recolonization by opportunistic bacteria (r-strategists), with significant increase in bacterial numbers and a low diversity (based on DGGE band pattern). All cultures stabilized after the initial recolonization phase (except Oz700) where competition due to crowding and nutrient limitation favoured bacteria with high substrate affinity (K-strategists), resulting in higher species richness and diversity (based on DGGE band pattern). The bacterial community was significantly altered qualitatively and quantitatively and may have a higher potential as invaders in the recipient depending on disinfection method and the time of release. These results have implications for the treatment strategy used for ballast water.
船舶压载水的运输代表了外来物种引入的风险。如果在吸取压载水时对其进行处理，那么在运输过程中，异养细菌将会重新殖民压载水。我们在实验室中调查了海水消毒后异养细菌的存活和演替情况，这是一种压载水处理和运输的模型系统。海水暴露于紫外线（UV）辐射、臭氧（2 个剂量）或未经处理，培养 16 天，并使用依赖培养和非依赖培养的方法进行检查。经 UV 和高臭氧剂量（700 mV）消毒后，菌落形成单位（CFU）的数量减少到检测水平以下，而低臭氧剂量（400 mV）则减少到初始水平的 1%。不到 3 天后，CFU 恢复到或高于对照、UV 和低臭氧处理的起始点，而高臭氧处理则需要略多于 6 天。消毒增加了基质的可用性并降低了细胞密度。缺乏竞争和捕食诱导了机会主义细菌（r-策略者）的重新殖民，细菌数量显著增加，多样性降低（基于 DGGE 带模式）。所有培养物在初始再殖民阶段后稳定下来（除了 Oz700），由于拥挤和营养限制导致的竞争有利于具有高基质亲和力的细菌（K-策略者），从而导致更高的物种丰富度和多样性（基于 DGGE 带模式）。细菌群落在质量和数量上都发生了显著变化，并且根据消毒方法和释放时间，在受纳水体中可能具有更高的入侵潜力。这些结果对压载水处理所采用的处理策略具有重要意义。
