Can Algae Save the World?

Most of us know algae as that unwelcome visitor in an aquarium.

But some species of this ancient group of organisms have a hero's role to play in cleaning up the world's waters.

Heavy metals are elements that are at least five times denser than water. This group of metals includes:

• Arsenic
• Mercury
• Cadmium
• Lead
• Chromium
• Silver
• Copper
• Selenium

Small amounts of some heavy metals, like copper, selenium and zinc, are essential for human health.

But in large amounts, or accumulated over time, these metals can be deadly.

Heavy metals enter our bodies through pesticides, contaminants in food, and even cigarette smoke. 

But the leading source of heavy metal contamination is water.

Heavy metals are normally found in soils. They end up in water naturally from flooding and erosion. 

But human activity adds a much larger load of heavy metals to the world's waters.

Human-made sources of heavy metal pollution include:

• Runoff from roads and landfills
• Industrial pollution
• Wastewater dumping
• Vehicle fuel leaks

That's why scientists continue to search for a safe, economical way to clear heavy metal contaminants from water.

Now, they may have found that solution.

Algae are ancient, mysterious organisms that share characteristics of plants, animals and bacteria. There are over 30,000 known species of algae, and these species aren't necessarily related.

Algae contain chlorophyll and rely on photosynthesis like plants, but they don't have roots, leaves or stems. Some are terrestrial and can move like animals. Others have some characteristics of bacteria.

Algae can range in size from microscopic organisms to ones that can reach up to 50 feet in length.

Algae produces more than two thirds of the world's oxygen, which supports marine life and adds oxygen into the air.

Algae is also a rich source of nutrients, so it can be harvested for food and even medicines. 

But that's not all. Research reveals that algae can also absorb heavy metals in water. Heavy metals bind to the cell walls of certain kinds of algae.

Researchers have found that an algae species called chlorella can clear more than 90% of heavy metals in water.

It can also clear up to 98% of certain kinds of metals, such as mercury and cadmium.

These discoveries could lead to large-scale algae farming and facilities to "wash" water through chlorella and other algae species. Scientists could also develop algae species with even more ability to absorb heavy metals.

Heavy metals captured using algae could be reclaimed for other uses, too.

Algae alone can't solve the problem of the world's polluted waters.

But the "superpowers" of this humble aquarium pest could provide a safe, economical tool for clearing some of the most dangerous toxins in waters around the globe.