A Description of Occurrence and Morphology of a New Species of Red‐Water Forming Strombidium (Spirotrichea, Oligotrichia)

We describe a red‐water ciliate, Strombidium lingulum n. sp., collected from a marine fjord in British Columbia (BC), Canada. In August, 1995, red‐brown streaks were observed in the waters of Kyuquot Sound. BC. These streaks were composed of a ciliate population with an abundance in the surface of ˜ 1.5 × 10 3 cells ml ‐1 . Density was reduced to < 50 cells ml ‐1 below the surface. The bloom persisted for only a few hours; cells were observed for 3‐4 days and were only occasionally observed in the weeks after the bloom. The red waters were speculated to be formed by a combination of downwelling events and an observed phototactic migration of the ciliate. As the ciliate was positively phototactic and pigmented, it may be mixotrophic; it was certainly heteroirophic, as it contained dinoflagellates and small ciliates in food vacuoles. Ciliates were preserved in Lugol's iodine and then both protargol stained and prepared for scanning electron microscopy.