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Sunday 8 September 2013

5 BIZARRE ALGAL BLOOMS


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5 bizarre algal blooms
By
Mother Nature Network, 6 September 2013.

Small wonders

Often disregarded as "pond scum," algae get a bad rap. Indeed, they might be the most underappreciated of life forms. Algae are primary producers of organic matter at the base of the food chain and as such, life as we know it probably wouldn't exist without them.

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Photo: Lebendkulturen.de/Shutterstock

While most algae are small - microscopic even - when they swarm they are among nature's grandest spectacles. To prove it, here's our list of some of the world's most wondrous, colourful, bizarre (and occasionally dangerous) algal blooms. (Text: Bryan Nelson)


1. Glowing waves

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Photo: Kevin Key/Shutterstock

The most magical algal blooms in the world might be those that occur along the southern coast of California, where the shore break occasionally glows with an otherworldly majesty. A bioluminescent species of phytoplankton there called Lingulodinium polyedrum emits a neon-blue light in response to stress, causing the waves to light up as they crash.

It's a spectacular sight to witness. Surfers even occasionally use the opportunity to hang 10 in the sparkling sea. Watch them ride the glistening waves below.



2. Qingdao's green bloom

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In what has become an annual occurrence, China's coastal city of Qingdao in July 2013 was inundated with the largest algal bloom in that country's history. Thick mats of algae lapped ashore, transforming sandy beaches into bright green lawns. The algae reportedly covered an area of 11,158 square miles, twice as much as the previous record.

Though local residents seemed to make the most of the spectacle, the swathe is likely a sign of an unbalanced ecosystem.

"Algal blooms often follow a massive discharge of phosphates or nitrates into the water. Whether it's farming, untreated sewage or some kind of industrial plant that is discharging waste into the water," researcher Dr. Brenda Parker said to the Guardian.


3. Dead zones

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Marine dead zones are hypoxic (or low-oxygen) areas in the world's oceans and lakes caused in large part by massive algal blooms. Huge blooms form near the mouths of major rivers as nutrients from agricultural runoff, such as nitrogen and phosphorus, pump into the sea. As the microorganisms feast on the influx of nutrients, the murky bloom can grow to a mammoth size, essentially snuffing out all the oxygen in the water.

The largest dead zone in the U.S., and second largest in the world, forms annually at the mouth of the Mississippi River in the Gulf of Mexico (it is shown above in red). The algal bloom can cover an area in excess of the size of New Jersey, and has become a major threat to the local fishing industry.


4. Red tide

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Photo: Chase Fountain/Texas Parks & Wildlife via NOAA

The good news is, that's not blood in the water. The bad news is, it could still be a sign of danger. Red tides can be as beautiful as they are toxic. Typically caused by dinoflagellates, these colourful blooms are often associated with the production of natural toxins that can kill marine creatures, and harm people too.

The colorization comes from the algae's pigmented cells, which can turn the water red, brown, green, pink or even purple. Not all red tides are toxic - many can be perfectly safe to swim through (if you don't mind wading through murky mats of microorganisms) - but swimmers should always exercise caution before diving into any algal bloom.


5. Milky seas

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For centuries mariners have returned from sea with strange reports of a glowing ocean. The phenomenon, deemed the "milky seas effect," is the eerie stuff of legend, even garnering mention in Jules Verne's "Twenty Thousand Leagues Under the Sea."

According to the bizarre reports, large swathes of open ocean, which appear normal by day, radiate with an eerie haze by night. The light does not come from the moon or stars; it comes from the sea itself.

It wasn't until 1995 that a merchant vessel decided to investigate. After collecting water samples, researchers concluded the glowing ocean was likely due to a bloom of tiny bioluminescent organisms, teeming across thousands of square miles.

The above composite satellite image shows the milky sea and the region of the ocean where it was spotted.


Top image: A red tide along the coast of La Jolla, San Diego County, USA. Source: California Department of Public Health (photo courtesy of Kai Schumman).

[Source: Mother Nature Network. Edited. Top image and some links added.]


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