Application of flow cytometry in ballast water analysis—biological aspects

Ballast water may, when discharged, cause the spread of nonindigenous and potentially invasive species. International ballast water treatment regulations have accelerated the development of new methods to detect, enumerate and assess the status of organisms in the water to be discharged. Flow cytometry (FCM) is a powerful technique with a broad range of applications with the possibility for multi-parametric analysis and the potential of combining it with other techniques being two strong advantages. This review will discuss whether FCM is suitable for ballast water analysis according to international ballast water regulations, and sum up the advantages and disadvantages. It will also give an overview of available labeling techniques. Finally, a discussion on the knowledge gaps and future potential for FCM within ballast water analysis is presented.