Small but Mighty . . . Microbes

Water is essential for life so is one of the important clues when searching for life on any planet. Except for heavily processed drinking water, you can find signs of life in nearly every drop of water on Earth; diatoms, dinoflagellates, micro-algae and blue-green algae (a type of bacteria) are common species. There are hundreds of thousands of species in these groups that do all the hard ecological lifting at the base of the food webs in the oceans, lakes and rivers, all the while sucking up megatons of carbon dioxide and pumping out endless amounts of oxygen. Most people will never see them. These dynamos are more ecologically noteworthy than any charismatic mega-fauna, but their image problem starts with their size . . . you can fit many individuals on the pointy end of a pin. Scientists like Michel Poulin have spent their careers in discovering new species and describing their contributions to aquatic ecology.

Malaysian freshwater diatom

freshwater diatom

It is a good thing that these aquatic organisms are small, because some are difficult to live with. Problem species are always present, but in low concentrations are no trouble. Under the right growing conditions they and other species explode in a bloom of abundance. Bloom conditions usually involve fertilization, lots of light and warmth, like when sewage leaks into a lake during the summer. Blue-green algae in high concentration regularly foul water sources for livestock and humans. Perhaps more famous are the blooms that occur in the oceans or red tides, because of their immense distribution and deadly toxicity; named for the color of the water due to the red or brown colored dinoflagellates. Less is known about the cause of red tides, but they regularly close the harvest of fish and shellfish that can pass on the toxins to humans.

In addition to their extensive roles in aquatic ecology, these microscopic organisms can tell stories about climate history. Diatoms live in intricate glass houses called frustules and each species can be identified by the design of this silica architecture. Scientists have discovered the correlation between the presence of certain species and the physical nature of the environment; temperature, pH, water hardness, etc. As diatoms die and their frustules accumulate in undisturbed sediments, they lay down a record of the water conditions. Thousands of years of lake sediments are regularly mined by researchers like Paul Hamilton and John Smol who look at communities of diatoms and add to our knowledge of climate history in Canada’s north. Aquatic microbes provide answers in a wide variety of aquatic situations and researchers have access to information about them through growing digital databases; e.g.  the National Phycological (algae) Database of Canada or CANA.

The Canadian Museum of Nature is showcasing water in  Canada’s Waterscapes, a traveling exhibit, and in a permanent Water Gallery at the Victoria Memorial Museum Building, so everyone has easier access to information about this incredible natural resource and its many inhabitants.

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