More Than Slime: The Benefits of Algae, From Earth’s Earliest Days to the Present

Sandra Folzer, Weavers Way Environment Committee

I’ve become enamored with algae. They have such a bad rep. Yet, we owe our existence to these early life forms, because they provided the oxygen that made our life possible and now supply 50% of our oxygen.

The alga story started with a single-cell bacteria that was able to produce oxygen through photosynthesis and drastically changed the early atmosphere. If algae had not produced oxygen, other life forms would not have evolved. Fossils attest to the existence of algae/seaweed over one billion years ago. 

Phycologists, who study algae, believe there are more than 72,000 species. They differ in means of reproduction, cellular structure and color, but they all have a slimy exterior, which they use to protect themselves from the sun’s radiation while they use the sun for photosynthesis.

Algae are not plants. They don’t have roots; instead, they have “holdfasts” at the base upon which they rest. Some green algae evolved into the first plant, the liverwort; “wort” means “root” in Old English.

Algae/seaweed are amazingly versatile and healthful. Nori, the seaweed used in making sushi, includes more nutrients and minerals than land vegetables, including vitamins A, B-complex, niacin, calcium, magnesium, selenium, iodine, iron and protein. It also contains amino acids, which are anti-inflammatory and lower triglycerides in blood, thus reducing the risk of heart problems. Eating seaweed gives all the benefits of omega oil, because fish take it in by eating algae. 

Some scientists believe that our ancestors developed their larger brains as a result of consuming seaweed. Brain cells need iodine and DHA, a type of omega-3 oil in the membrane of brain cells. Since seaweed is an excellent source of these nutrients, some believe homo sapiens originated near Cape Agulhas at the southern tip of South Africa, which is one of the most productive seaweed colonies in the world.

Of course, algae have a downside, too. Every summer I have to combat it in my pond. Barley straw usually works, but this past summer, we were inundated with a new feathery algae that took over the pond. The state Fish and Wildlife Service recommended introducing sterile grass carp to take care of the problem. They are vegetarian so will not eat other fish. 

That solution sounded easy until I learned I needed a permit to buy the fish. I nearly had to promise my firstborn, along with a $100 fee to get the permit. I imagined they’d be ordinary-looking fish, but my neighbor informed me that theirs have grown to a length of five feet. Imagine me swimming around with a fish nearly as big as I am.

You’ve probably heard about algae blooms, which are ruining many lakes and seas. One culprit, called a blue-green “algae,” is actually a bacteria. Other true algae are problematic because they take oxygen out of the water, kill the fishing. 

I wondered how this could happen, since algae produce oxygen. Because of an overabundance of nitrogen runoff from industrial farms and industry, the algae grow too rapidly and crowd out one another. Any oxygen produced is used up during decomposition, causing hypoxia, or lack of oxygen. The algal blooms also prevent sunlight from penetrating the water, which prevents phytoplankton and algae from manufacturing their food from sunlight. As a result, the fish often die from lack of oxygen. 

These blooms become “dead areas” where marine life cannot survive. More than 300 dead zones worldwide were reported in 2018, according to Scientific American. The magazine also reported that the largest dead zone in the United States is in the Gulf of Mexico, and it occurs every year due to runoff from the Mississippi Basin.

Some types of algae blooms are poisonous to people and livestock. Toxic algae blooms may be difficult to identify. According to the Missouri Department of Natural Resources, they look like pea soup, though they may be of different colors. Toxic blooms also have a putrid odor. 

If you’re in doubt about whether a body of water with algae is safe, stay out and don’t let pets near it. The most common health effects of algae-bloom contact are rashes, but symptoms may include vomiting, diarrhea, dizziness and respiratory problems. 

In 2019, 176 dolphins died from algae blooms near Sarasota, FL. According to the Florida Fish and Wildlife Conservation Commission, many manatees and sea turtles have also been killed.

Scientists believe we can reduce algal blooms by limiting nitrogen-rich fertilizers and preventing sewage leaks and industrial waste. Congress passed the Harmful Algal Bloom and Hypoxia Research and Control Act in 1998 to combat the problem.

It would be easy to condemn algae for all the trouble they cause, but they also are beneficial. Aside from being nutritious and providing half of our oxygen, algae has many benefits:

  • Algae are a potential source of fuel.
  • Algae are a healthful food.
  • Algae may be more effective than antibiotics for boosting livestock growth.
  • According to Ruth Kassinger’s 2019 book “Slime: How Algae Created Us, Plague Us and Just Might Save Us,” algae reduce flatulence (methane) when fed to cows, if we do that we could cut 15% of carbon dioxide emissions.
  • Algae are used in many products from toothpaste to lipstick. (Carrageenan, for example, is made from alga.)
  • Algae are fed to farmed fish to replace fish, which are becoming scarce.

I definitely have a new appreciation of algae. I recommend reading Kassinger’s book if you want to increase your algae knowledge.