image by: A Toxic Inconvenience
Innumerable microscopic algae help anchor aquatic ecosystems; they turn sunlight into food, and themselves serve as food for water-dwelling frogs, fish, snails, and insects.
But under the wrong conditions—warm water, too much sunlight, and excess nutrients from agricultural or sewage runoff—some species of algae can multiply uncontrollably, forming green, red, blue-green, or brown masses that smother the surface of waters and can produce potentially dangerous toxins.
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Toxic algae blooms appear when nutrients from farm fertilizer and manure run off into rivers and streams and other bodies of water, triggering the growth of microscopic single-celled organisms. The blooms are actually cyanobacteria but widely referred to as algae. Blooms often have a rotten smell and resemble spilled blue-green paint or split-pea soup.
If a growing number of scientists have their way — and can get federal funding they say is desperately need to protect the public — algae forecasts could become as common as weather reports, and as essential.
In Florida, the Army Corps of Engineers is working to combat a growing environmental menace: blue-green algae. Nitrogen and phosphorus runoff from farms and subdivisions combines with warm summer weather to create massive blooms of algae in rivers and lakes that can be toxic.
In central Florida, Lake Okeechobee has been hit hard in recent years.
Algae and cyanobacteria are simple, plant-like organisms that live in water. Algae and cyanobacteria can quickly grow out of control, or “bloom.”
Cyanobacteria can produce toxins that cause asthma-like symptoms, severe vomiting, diarrhea, or irritated skin or eyes.
In a warming ocean, Alexandrium algae are shredding marine food webs—and disrupting beloved Alaska traditions.
So why don’t we have algal blooms all the time? This is because algae don’t just require nutrients to grow. Like any plant, factors such as temperature and light availability are also important in determining how quickly algae grow and whether they form blooms. Blooms also need slow moving or still water to become established.
The world’s lakes and oceans are teeming with phytoplankton. These microscopic photosynthetic organisms (mainly algae) make up the base of aquatic and marine food webs. Although phytoplankton play a critical role in sustaining life, some species of single-celled algae can be harmful when they occur in large numbers. When conditions are right, these species rapidly reproduce until they create huge masses of algal cells.
Freshwater Harmful Algal Blooms happen most often where there are high levels of nutrients like nitrogen or phosphorus present in warm, still waters like lakes, ponds, or reservoirs. They can also occur in rivers, especially during summer months.
Researchers are racing to find solutions to outbreaks of blue-green algae that are increasing in frequency and severity. Carpets of stinking algae have sickened people and animals and hurt the fishing and tourism industries.
Toxic bloom is terrible for acquatic life – the good news is, we may be able to harness the sludge as a carbon-neutral biofuel.
In a bloom, millions of these tiny organisms produce a paralyzing neurotoxin that prevents fish and marine life from respirating. It’s mildly dangerous for humans too: The toxin can go airborne and be dangerous for some people with respiratory sensitivities. And doctors aren’t sure what the long-term effects of breathing air with the toxin may be.
Breaking waves can send algal blooms airborne.
Just as tiny droplets collect into cloud, microscopic algae congregate into blooms that can be seen from space. Every year, harmful algal blooms (or HABs) force beach closures, contaminate drinking water, and sicken people and their pets.
The long-term health effects of harmful algal blooms in people and animals remain unclear.
The excessive algal growth, or algal bloom, becomes visible to the naked eye and can be green, blue-green, red, or brown, depending on the type of algae.
Algae are always present in natural bodies of water like oceans, lakes, and rivers, but only a few types can produce toxins.