What is pond scum, or algae? Harmful or Useful?


The word algae is the plural form of an incredible range of organisms that we usually associate with single-celled life forms having a nucleus and being able to use photosynthesis to create their own food from sunlight and carbon dioxide.

pond scum-algae uses

Their waste is oxygen without which we humans would die off in a matter of minutes. Algae can also be multi-celled and grow to enormous sizes such as the giant kelp seaweed that can grow to over 50 meters long.

Besides providing us with oxygen, if properly farmed and harvested, which many are already doing, it could help mitigate hunger and provide sorely needed nutrition throughout the world.

The term algae is now reserved for eukaryotic pond scum, that is, organisms having a nucleus enclosed by a membrane. What used to called blue-green algae is now recognized as bacteria in that it is prokaryotic, having no internal nucleus.

Nevertheless they also rely on photosynthesis to create their nutrients and expel oxygen as waste. So blue-green algae is now known as cyanobacteria from the Greek word for blue.

The number of different algae species is unknown but we do know that there are hundreds of thousands of them. The Museum of Natural History in Washington, D.C. has over 300,000 different species cataloged in their collection.

Pond Scum as Fertilizer and Farm Runoff

Farms are routinely villanized when their fertilizer residue is allowed to runoff into streams that feed larger tributaries. The runoff eventually ends up in bodies of water such as the Chesapeake Bay where it creates dead zones from lack of oxygen in the water.

What happens is that algae captures the nutrients from farm runoff, such as phosphorus and nitrogen, and combined with sunlight and warmth, spurs rapid growth which we refer to as algae blooms. If that nutrient rich algae could be harvested, which it is in many countries, it could be used as fertilizer itself.

Algae gets a bad rap for sucking all the oxygen out of whatever pond or waterway it inhabits and killing off fish and other aquatic life that needs that oxygen to survive.

The truth is a little different. Remember, algae creates oxygen as its waste product. It doesn’t use oxygen. While algae gets the blame for creating hypoxic, or dead zones, in bodies of water, it is the bacteria that feeds on dead algae that takes up the available oxygen.

No matter, if we didn’t have the algae bloom, we wouldn’t have such a huge mass of dead, decaying pond scum to feed the bacteria and we wouldn’t have large dead zones in the Gulf of Mexico or Chesapeake Bay.

Green algae and pond weed; food or fuel?

Nutritional uses of algae range from eating it as a food, such as the seaweeds that are consumed in Asia and dietary supplements which are gaining in popularity in the U.S.

Undoubtedly the use of pond scum in nutritional supplements will continue to grow as more information is made available on their benefits; assuming of course that the pharmaceutical industry and the FDA don’t put the brakes on the use of algae for its health benefits.

The three major algae supplements to be covered are Spirulina, Chlorella and Astaxanthin.