Impeller pumps are the most common pump used in UNOLS vessels and can affect particle assemblages under certain conditions (Cetinic et al., 2016). Diaphragm and peristaltic pumps are recommended in order to minimize artifacts introduced by the pump. Past comparison (Fig. 3B-C in Westberry et al., 2010), as well as a recent comparison between data collected from the in-line system and with Niskin bottles found a very good agreement.
We have used the following pumps: