Diatom-derived ecological facilitation in Salish Sea plankton communities: A species-specific study

Phytoplankton serve as the globally dominant primary producer. They support biologically rich and diverse marine ecosystems like that of the Salish Sea. Much of this primary production can be attributed to planktonic diatoms. Seasonal diatom blooms are commonly followed by the flourishing of other phyla of nano-plankton. We propose a novel hypothesis that diatoms play a facilitative role in Salish Sea phytoplankton, which is contrary to all other publications that have proposed diatoms have an allelopathic effect on competing phytoplankton (Yamasaki et al. 2011; Suikkanen et al. 2011; An et al. 2008). Our preliminary experiment showed significant evidence of diatom-derived chemicals positively affecting the growth rates of four phyla of non-diatom phytoplankton. During this experiment, we observed a dominance of Skeletonema diatoms by the end of our bloom incubation period. Through species-specific growth experiments on a diverse set of nanoplankton, we used this study is to uncover the role of chemical facilitation by diatoms to control planktonic populations in the Salish Sea and whether any species of diatom has a disproportionate influence on this ecological facilitation.