A rapid assay of phytoplankton viability

船舶吸收和释放压载水可以将微生物从全球海洋的一个部分运送到另一个部分，对自然生态系统可能产生负面影响。为了减少引入外来微生物所带来的威胁，《控制和管理船舶压载水和沉积物国际公约》对船舶压载水处理实施了全球性规定，自2019年9月起生效。该公约对排放的沃茨中活细胞的浓度规定了限制。美国现有的法规在规范活细胞的排放方面与国际标准不同。根据定义，活细胞能够繁殖，但非活细胞不能。由于压载水处理的目的是防止微生物的繁殖，因此细胞存活率为压载水处理提供了一个合理的标准。紫外线C（UVC）辐射可以对压载水进行消毒，广泛应用于饮用水和废水处理。UVC治疗通过破坏核苷酸使细胞不能存活，但不一定完全杀死它们。因此，如果在用UVC处理的水中用美国强制的活/死测定法进行测试，则无活力（因此非侵入性）细胞登记为活细胞。压载水处理中UVC的接受取决于开发出准确的可行性替代试验。证明可行性的最直接方法是生长试验。然而，生长测定可能需要数周才能完成，因此不适合用于船上测试，以确保压载水处理系统符合监管标准。在NSERC和Trojan UV的支持下，开发了一种基于荧光的浮游植物活力快速测定（RAPV），并在实验室进行了测试。拟议的研究伙伴关系的目标是测试RAPV的功效;建立快速检测的理论基础;并改进确定单细胞而不是批量组装的活力的技术。在5年内，这项研究将开发用于评估浮游植物生存能力的测试，这些测试将立即应用于压载水处理市场，但也将允许在受损沃茨的评估和处理、自然种群研究以及用于食品、生物燃料和其他高价值产品的藻类大规模培养方面开发新的工业市场。

Uptake and release of ballast water by ships can transport microorganisms from one part of the global ocean to another, with potentially negative consequences for natural ecosystems. To lessen the threat posed by the introduction of alien microorganisms, the International Convention for the Control and Management of Ships' Ballast Water and Sediments imposes global regulations for treatment of ships' ballast water, effective September 2019. The Convention imposes limits on the concentrations of viable cells in discharged waters. Existing regulations in the USA differ from the internationally standards in regulating the discharge of living cells. By definition, a viable living cell is able to reproduce, but a nonviable living cell is not. Because the goal of ballast water treatment is prevention of reproduction of microorganisms, cell viability offers a reasonable standard for treatment.Ballast water could be disinfected by application of ultraviolet C (UVC) radiation, which is widely used in treatment of drinking and waste water. UVC treatment renders cells nonviable by damaging nucleotides but does not necessarily kill them outright. Consequently, nonviable (so non-invasive) cells register as living if tested with the US-mandated live/dead assay in water treated with UVC. Acceptance of UVC for ballast water treatment depends on development of accurate alternative tests of viability.The most direct means of demonstrating viability is with a growth assay. However, growth assays can take weeks to complete, so are inappropriate for shipboard testing to ensure that a ballast water treatment system complies with regulatory standards. With the support of NSERC and Trojan UV, an hours-long fluorescence-based Rapid Assay of Phytoplankton Viability (RAPV) has been developed and tested in the laboratory. The goals of the proposed research partnership are to test the efficacy of the RAPV; to establish the theoretical foundations underlying the rapid assay; and to refine techniques for determining viability of single cells rather than bulk assemblages. Within 5 years, this research will develop tests for assessing phytoplankton viability that have immediate application to the ballast water treatment market but will also allow development of new industrial markets in assessment and treatment of impaired waters, in studies of natural populations and in mass culture of algae for food, biofuels and other high-value products.