Microlife in California Rice Fields

By Ken W. “Creekman” Davis

How can we possibly compare 17th century canals of the Dutch Republic to California rice fields in 2018? It’s easy! In 1657, Anton van Leeuwenhoek, the “Father of Microbiology” reported the discovery of “Miniscule Animalcules” in many of the waters of the Dutch Republic including the Delft Canal. He reported in a series of letters to the Royal Society of London that the water beasts were, “So small, in my sight, that I judged that even if 100 of these very wee animals lay stretched out one against another, they could not reach the length of a grain of coarse sand.” His observations were originally ridiculed because at the presence of microscopic organisms was met with scientific disbelief. His discoveries included bacteria, which he observed with a self-made microscope.

Many of the same wee animals thrive today in California’s winter-flooded rice fields. When the fields are wetted, millions of bacteria and bacteria-like organisms begin to break down the rice straw and release carbon, nitrogen, phosphorous and other elements necessary for plants and animals. This is routine! Good bacteria are major players in the decomposition of organic matter and the cycling of chemical elements in soil and waterways. We frequently forget that bacteria are possibly the most important group of organisms on the planet.

bacteria under microscope

Bacteria are also food for microscopic one-celled animals that form the Lower Aquatic Food Web and thrive in winter-flooded rice fields. Protozoa eat the bacteria, larger protozoa eat their smaller cousins, rotifers and copepods eat the protozoa, and water bears eat all of them. Eventually, larger animals such as water fleas and scuds dine on the bacteria, all the previously mentioned critters, plus a good helping of algae. Those nutritious creatures are moved up the food web to hungry birds and fish such as the juvenile salmon studied in the Nigiri Project.

bacteria under microscope

The winter-flooded rice field connection with Anton van Leeuwenhoek was recently germane when I photographed a colonial animal that that appeared to have granular rust-colored metal stalks. In 1702, the amateur scientist described, and drew, with the aid of his primitive microscope, an animal he called the “Iron Protozoa.” His comments and crude red crayon drawing of the metallic-looking stalks caught my attention (Science has since determined the stalks are formed by granular calcium, iron, and manganese). Leuwenhoek’s curiosity about water creatures 316 years ago helped me to determine the odd microscopic creature’s identification. (In fact, his description and drawing were significantly more informative than my extensive library of modern science.) The rusty-stalked colony of protozoa is Anthophysa vegetans, now known as the Iron Flagellate.

bacteria under microscope

I look forward to sharing more of the microscopic aquatic world found in rice fields soon, including high definition video. Stay tuned!

Ken W. “Creekman” DavisKen W. “Creekman” Davis is an aquatic biologist and wildlife photojournalist with more than 30-years experience. His images have been published in more than 4000 different periodicals, newsletters, brochures, encyclopedias and websites.