Tintinnids – beautiful and strange life forms | Natural History
Published 6:00 pm Tuesday, August 28, 2012
By Russel Barsh and Madrona Murphy
Smaller than a flea’s egg, this little creature looks like a hairy amoeba in a wine glass, busily darting to and fro, or thoughtfully twirling its crown of tiny hair-like cilia before making its next move. Strange as they look to us, tintinnids play an essential role in all freshwater and marine ecosystems.
A few 100 species of tintinnids worldwide convert as much as one-fourth of the solar energy captured by single-celled photosynthetic organisms, into fatty biomass that the smallest multi-cellular animals can eat: a crucial link in the food web. In some high nutrient or low oxygen aquatic ecosystems, including Fisherman Bay, they may process up to 90 percent of all primary (photosynthetic) production into tasty food for copepods and the tiny free-swimming larvae of worms, mollusks and crustaceans
Tintinnids belong to a group of single-celled organisms that use hair-like cilia for propulsion. They spin their cilia like tiny propellers to generate strong currents that move them around, as well as suck prey into their mouths.
Tintinnids are easily identified by their transparent vase-shaped or tubular “shell” or lorica, which is composed mainly of protein. Lorica shapes are species-specific. And loricae are tough enough to fossilize, so paleontologists know more about tintinnids than most other single-celled organisms. Tintinnids have been on earth for at least 635 million years, and probably longer, judging from fossils discovered in 2011.
The function of loricae remains unclear, however. Loricae do not appear to be an effective defense against larger animals. Loricae may help tintinnids stay afloat, just as the strange shapes and elongated spines (setae) of many diatoms increase their surface area and delay sinking. Some tintinnids may store potential food supplies by carrying bacterial passengers in their lorica.
When food grows scarce in winter, tintinnids encyst and sink into the sediment to rest there until the water warms and phytoplankton prey are again abundant. Tintinnids can re-emerge, in vast hungry numbers, within days of a plankton bloom, and they appear to be one of the reasons (together with nutrient limitation) why blooms do not last very long. In fact, dinoflagellates and diatoms may have evolved algal toxins principally to ward off tintinnids, although sadly these chemical weapons can also be toxic to fish and other vertebrate animals—including us.
All you need to hunt for tintinnids is a jar of fresh seawater, a coffee filter, and a microscope that can attain at least 200 times magnification. Use the filter to concentrate the sample before examining it. Or follow Kwiaht’s Facebook page to learn more about the beautiful and strange life forms that inhabit our coastal waters! And if you see strange colors in the water, leave a message at 468-ITOX (468-4869) so that a local volunteer can get a sample for identification.
