Free-living Freshwater Protozoa: A Color Guide

Rating:
Summary: Notosolenus? or Petalomonas?
Review: D. J. Patterson is a Professor of Biology at the University of Sydney, and although his book was written primarily for specialists as a guide to identifying approximately 350 of the most common kinds of freshwater protozoa, it also holds much that will be of real interest to the amateur naturalist. The book falls into three parts: an Introduction, the guide or Key, and concluding supplementary materials.

The 22-page Introduction covers such topics as: What protozoa are; Distinguishing protozoa from other microbes; How to choose and care for a microscope; Contrast enhancement; Techniques of microscopical examination; Drawing and photographing protozoa; Video microscopy; Where to find and how to collect protozoa; Keeping samples; etc. A great deal of useful and practical advice will be found in this Introduction, some of which I haven't seen elsewhere.

For example, in discussing microscopes Patterson suggests that phase contrast optics will allow the protozoologist who is observing living organisms "to see more and to see it with ease," and that ideally phase contrast objectives should be used in preference to the bright-field (normal) variety (p.11). To illustrate the different kinds of visual information which different contrast enhancement techniques provide, he gives us, on pages 155-57, a fascinating series of photographs of the Paramecium bursaria as viewed under Bright-field, Phase contrast, Differential interference contrast, Dark ground, Interference contrast, Polarized light, Fluorescence microscopy, and various types of staining. The differences are striking.

I was also interested to note the author's concern for the welfare of these tiny and extremely delicate and fragile organisms while we are engaged in observing them. He warns us that "Usually, active motility is a sign of distress. Typical causes might be pressure from a coverslip, overheating, or depletion of oxygen. The cells move until they find a more favorable site." And he advises us that "The use of minimal illumination or gently blowing on a preparation as you observe it often 'calms' protozoa," thereby making them easier to observe (p.13). Other methods of limiting distress are also described, and great care should be taken not to heat the organism.

Following the Introduction we are given a 'Classification of protozoa,' line drawings of the main genera, and then the main part of the book, the step-by-step guide to identifying protozoa.

For each of the organisms covered in the book, the author gives a detailed description and bibliographical references, a color microphotograph (with the type of contrast enhancement used), line drawings which point up certain important features, and occasionally a detailed line drawing of the entire organism. The book concludes with line drawings of six Protozoan communities (Planktonic, Attached, Benthos, Organically rich benthos, Anoxic benthos, Sewage treatment plants), a 10-page Glossary of Terms, a scholarly Bibliography of over 400 items, and an index.

Dr Patterson's book is well-organized, easy to use, well-printed in double columns on 222 quarto size pages of high-quality glossy paper, stitched, bound in a waterproof wrapper, and sturdy enough to be taken into the field along with a field microscope such as the Swift FM-31-P40 LWD.

Although experts may find details to quibble about, speaking as an amateur I have only two criticisms of the book. The first is that the color microphotographs, although generally good, measure only 43mm x 70 mm and are far too small. Protozoa such as the Stentor (Fig. 216) or Tachysoma (Fig. 265) are among the most strikingly beautiful creations of Nature, and although Patterson's microphotography may not be quite up to the standards of a Werner Nachtigall, I get the feeling that he is a much better photographer than the tiny and rather average reproductions in this book would seem to suggest. All of the photographs are small, some are very dark, others not particularly clear, and few do full justice to either Nature's or, I suspect, Dr Patterson's own artistry, though together with the line drawings (most of which are are even tinier) they are adequate for purposes of identification.

My second criticism has to do with the very high price of the book, a price which one would have thought ought to have ensured a size and quality of color reproduction far superior to what we have been offered here. But despite its high price and its underwhelming reproductions of what must have been striking originals, this is a book which has much to offer any protozoa specialist or enthusiast who may be trying to pin down unidentified protozoa. It may just help you to decide whether you are looking at a Notosolenus (Fig.80) or a Petalomonas (Fig.83), or at something else! And students ought certainly to at least head for the library to read its excellent Introduction.

Rating:
Summary: A useful aid for protozoan identification
Review: I have been examining the biota in activated sludge for over 15 years and have found this book to be the best reference for color micrographs of protozoa. Size of organisms, and features that are useful in identifying them are clearly indicated. The authors use both phase-contrast and DIC optical systems to very clearly present numerous organisms. There is also a short section in the back that gives the reader insight into some of the ecological roles of the various organisms. This book would be valuable to anyone microscopically examining activated sludge.

Rating:
Summary: The Best Book for Identifying Living Protozoa
Review: Patterson's color guide to free-living freshwater protozoa is probably the most useful of the protozoan identification guides for living protozoa, especially if you are examining the protozoa under phase contrast. Living protozoa do not necessarily look much like some of the drawings in manuals. The photos, while a bit on the small side (probably because of the cost of printing) are thus very helpful (and very beautiful). Using Kudo's old standard "Protozoology" and Jahn, Bovee and Jahn's "How to Know the Protozoa" as a back up you can identify many of the organisms you examine and be fairly certain of the result. I understand the high cost, as the market for this book is probably somewhat limited. Freshwater microscopy is not like even butterfly watching in popularity, but there are a small number of devotees worldwide. Professionals are also somewhat fewer in number than in other specialties. This does not mean that protozoology is unimportant, only that it is less popular than some other areas of natural science.

Given this, the appearance of a book of this quality is remarkable. Its utility is evident and I have now used it several times to help me identify protozoa in samples from sinkholes in New Mexico. I recommend it without reservation.