Blue Ciliates (Folliculinopsis sp.)
These deep blue, single celled protists reside on basalt substrates and are very common surrounding hydrothermal vents along the Juan de Fuca ridge. They are colonial creatures that live inside of self-constructed tubes called loricae, from which extend two arm-like appendages. They are one of the first colonizers to a vent field, and may help to initiate the colonization process.
Due to the high concentrations of bacteria found on and in the ciliates, scientists were intrigued by the possible evidence of a bacterial-protozoan symbiotic relationship. Experiments proved that a relationship did exist, the first of its kind to be discovered. While the bacteria gain a habitat for survival, the protozoa obtain food and protection via chemical mechanisms from the bacteria.
References:
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0485.2006.00118.x/epdf
