Environment Planet Earth Mysterious Algae Vortex the Size of Manhattan Can Be Seen From Space By Bryan Nelson Writer SUNY Oswego University of Houston Bryan Nelson is a science writer and award-winning documentary filmmaker with over a decade of experience covering technology, astronomy, medicine, and more. our editorial process Twitter Twitter Bryan Nelson Updated July 29, 2018 Algal vortex seen from 's Operational Land Imager (OLI). NASA Share Twitter Pinterest Email Environment Weather Outdoors Conservation According to myth, Charybdis was a sea monster that consumed ships by sucking them into deadly whirlpools. A new image provided by NASA's Operational Land Imager, an instrument aboard the Landsat 8 satellite, might have just revealed Charybdis' real-life lair in the Baltic Sea. At the very least, this image proves that reality is ever more stranger than fiction. This eerie-green vortex is actually an algal bloom roughly the size of Manhattan. Scientists aren't sure exactly what's causing the hypnotic whirlpool action, but they suspect it's an example of an ocean eddy that's pumping nutrients from the depths, thus providing a giant feeding trough for all of that algae, reports NASA's Earth Observatory. What's worse is the bloom is probably toxic and likely to cause a marine dead zone, a region in the ocean depleted of oxygen, and thus devoid of most life. The likely culprit behind these massive blooms is cyanobacteria, or blue-green algae, an ancient type of marine bacteria that captures and stores solar energy through photosynthesis like plants. When these blooms get particularly large, they cause dead zones by depleting the oxygen content of the water, a problem that is becoming a regular occurrence in the Baltic Sea where runoff from sewage and agriculture provides surges of nutrients for the blue-green algae to feast on. In fact, oxygen levels in recent years here have dropped to their lowest levels in the past 1,500 years. According to researchers from Finland's University of Turku, the dead zone this year is estimated to span about 27,000 square miles. These algal blooms are also toxic, and beaches all along the Baltic Sea must be regularly closed due to their presence. To be fair, dead zones aren't just a problem in the Baltic Sea. They're becoming more and more common around the world, and one of the largest in the world forms in the Gulf of Mexico, at the mouth of the Mississippi River. Charybdis, it would seem, is multiplying. And as we continue to dump our waste into rivers around the world, we are feeding it with a conveyor belt of nutrients.