Algae is a funny old thing. This group of photosynthesising aquatic organisms come in many shapes and sizes (but mostly very, very small) and you’ll probably recognise them from kelp and seaweed, but there is a lot more to them than that. For example, algae are a critical part of the food chain, as well as producing a huge amount of the oxygen we breath.


Here are a few vital algae facts to help you enjoy, understand, and respect one of the world’s most important organisms.

  1. Take a breath: half the oxygen you breathed in was made by algae. We don’t think much about algae, except when we see yucky, slimy scum on a pond. But algae first oxygenated Earth’s atmosphere. If all Earth’s algae died tomorrow, we would soon expire, too.
  2. Swallow a single drop of ocean water and you’ll swallow thousands of microscopic algae. There are more algae in the oceans than stars in the Universe.
  3. Algae are the base of the marine food chain: without algae, there would be no fish or any other sea animals.
  4. All plants evolved from algae. Without plants to eat, fish would never have evolved to become land animals, including us.
  5. Farmers have been feeding a little seaweed to their animals’ feed for at least two thousands years, recognising its health benefits. They have long added a little seaweed to soil where it acts as a biostimulants, increasing crop yield by 10 to 30 percent. The seaweed additive market is $450 million and, while still in its infancy, employs many hundreds of harvesters in Canada, Maine, and northern Europe.
  6. Coral reefs depend on algae. Symbiotic algae that live inside corals (which are animals) create sugars through photosynthesis. Those sugars provide 90 percent of the corals’ energy needs.
  7. Certain algae called zooxanthellae (“zoox”) live inside corals, which are animals. The algae produce sugars that they pass to the corals, providing 90 per cent of their energy needs, while the corals provide nitrogen and shelter to the algae. Without this symbiosis, we would not have corals reefs, which are highly valuable to mankind. Seventeen percent of the world’s protein comes from reefs. One billion people depend on reefs for food, protection from storms, or employment.
  8. Warming oceans cause corals to eject their zoox, which produce lethal superoxides in higher temperatures. Ninety-three percent of all coral reefs are damaged by the loss of zoox. Sixty percent of the Caribbean’s reefs have already disappeared. Many experts believe coral reefs will be extinct by mid-century, at the latest.
  9. Our brains are dependent on the iodine and omega-3 oils that algae contain. When we don’t eat algae (or sea creatures that dined on algae) we run the risk of thyroid deficiency and lower IQs. Some scientists attribute the expansion of the hominid brain to access to seaweed and algae-eating fish.
  10. Agar, the medium that coats the bottom of petri dishes and is an irreplaceable part of medicine and science, is also an algae-derived hydrocolloid. Shortages of the seaweed Gelidium threaten laboratories worldwide. There is no substitute.
  11. Algae are in your kitchen and bathroom. Listed as carrageenan or alginate, you’ll find them in ice cream where they prevent ice crystals from forming, in chocolate milk to keep cocoa suspended, and in salad dressing to keep the components mixed. Algae gel your toothpaste, thicken your body lotion, and coat tablets to hold the ingredients together. And that’s just the start!
  12. Oxybenzone and similar sunscreens that wash off our bodies are deadly for corals and other marine life. Hawaii and other states are banning these sunscreens. Algae have evolved protection from UV rays, and algae-based sunscreens hold promise.
  13. The US Navy has run ships and planes on non-polluting fuel made from the oils in algae. The price of algae oil has dropped radically and new technology will drive it down further. If the price of fossil fuels reflected the cost of their environmental damage, we would be flying jets on algae fuel.
  14. Algae can substitute for oil and natural gas in plastics. A Mississippi company called Algix is making the soles of running shoes and other products with EVA made from algae. In 2019, they will use more than 5 million kilos of pond scum. Ten billion pairs of running shoes are made annually; the potential for algae plastics is big.
  15. Harmful algae blooms are getting bigger and lasting longer in our era of climate change and fertiliser run-off. The blooms already cause hundreds of millions of dollars of annual losses to fishermen and tourist economies around the world.
  16. Red algae living on the Greenland ice sheet account for 5 to 10 per cent of the ice sheet’s shrinkage. The algae turn the snow pink when the slightest melt occurs. This “watermelon snow” absorbs light, which heats the snow, and creates a feedback loop that hastens the disappearance of snow.
  17. The burps and flatulence of livestock constitute 15 per cent of the greenhouse gases that mankind emits each year. Australian researchers recently discovered that a little Asparagopsis seaweed added to animal feed stops gut bacteria from producing gas. Emissions are reduced by 50 to 85 percent.
  18. Can algae combat global warming? Seeding the iron-poor Southern Ocean with iron dust encourages algae blooms that absorb carbon dioxide and sequester it to the ocean floor. Whether the technique is effective is not yet clear; more research is needed.
Bloom: From Food to Fuel, the Epic Story of How Algae Can Save Our World by Ruth Kassinger is available from 4 July 2019 (£16.99, Elliott & Thompson)
Bloom: From Food to Fuel, the Epic Story of How Algae Can Save Our World by Ruth Kassinger is available from 4 July 2019 (£16.99, Elliott & Thompson)


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