Marine Creatures of the Northern Gulf of Mexico – Ciliate Protozoans

After two articles on protozoans, we now know what these animal-like creatures are.  We have discussed some that move by flagella, and others than move by pseudopodia.  The last group by short flagella called cilia.

Ciliates are often covered with these small hair-like structures and can move them relatively fast.  Thus, they swim MUCH faster than flagellates, and both are faster than the amoeboid sarcodinids.

They are easy, and not easy, to identify under a microscope.  You will be examining the slide seeing diatoms and dinoflagellates scattered across the screen, an occasional flagellate slowly swim by, the very slow fried egg-looking amoeboid slime through, and then a dot/cell will zip by at high speed.  That was a ciliate.  Easy to identify because anything moving that fast is a ciliate.  Hard to identify because you have NO idea which one.  Under the heat of the light, they will eventually slow down, and you can better see them for identification.

Most ciliates have an open mouth and what is called an oral groove.  This groove acts like a throat leading the food to the food vacuole – where it is digested.  Waste will live the protozoan either through the cell membrane, or back out the mouth.  At the opening if the mouth are numerous cilia that generate a current sucking up food like a vacuum cleaner and moving it down the oral groove.  Most have many nuclei which are easily seen under the scope.  They move through the water column collecting food and moving it down the food chain.  Most lack shells, so do not contribute to the sediments of the ocean floor or on our beaches.

Up to this point in the series we have been discussing the microscopic phytoplankton and zooplankton found in the Gulf of Mexico.  These are creatures few know about, nor do they understand their importance in cycling food, energy, nutrients, and other chemical processes that keep the ecology of the northern Gulf of Mexico in balance.  But is now time to turn our attention to the larger – macroscopic – creatures of this world.  We begin with seaweed.

 

References

Yaeger, R.G. 1996. Protozoa: Structure, Classification, Growth, and Development.  Chapter 77. Medical Microbiology, 4^th edition. https://www.ncbi.nlm.nih.gov/books/NBK8325/#A4082.