The monthly San Pedro Ocean Timeseries cruise was last week. Just like every SPOT sampling expedition, I collected plankton to 1) practice drawing protists while simultaneously practicing my microscope-based identification and 2) get an idea of who’s winning, who’s making moves, and think about WHY in the protistan community.
Because the microbe communities are so responsive to environmental changes, the possibility of seeing something unexpected, weird, or simply out-of-place is high. For example, I might see high densities of unusual diatoms out of season or large quantities of a specific heterotrophic protist. This cruise, as I scanned through the relatively banal plankton community on the inverted compound microscope, I spotted an extremely large, polka-dotted ciliate that I could not identify beyond the fact that it was indeed a ciliate belonging to the hypotrich group therein.
Ciliates are extremely diverse in lifestyle, size range, and morphology. All ciliates have lots of tiny cilia on their cell surface that are used for mobility and controlling water currents in their proximity. All known planktonic ciliates earn a living by consuming things smaller than them. We know from many quantitative studies that ciliates play a major role in energy flow in planktonic food webs as important intermediaries between pico/nano plankton and microzooplankton like copepods.
