
NASA has revealed an incredible image of a gigantic 'whirlpool' of algae in the Baltic sea.

Every summer, phytoplankton spread across the northern basins of the North Atlantic and Arctic Oceans, with blooms spanning hundreds and sometimes thousands of kilometers.

Blooms this summer off of Scandinavia seem to be particularly intense, NASA said.

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On July 18, 2018, the Operational Land Imager (OLI) on Landsat 8 acquired a natural-color image (above) of a swirling green phytoplankton bloom in the Gulf of Finland, a section of the Baltic Sea. Note how the phytoplankton trace the edges of a vortex; it is possible that this ocean eddy is pumping up nutrients from the depths. For scale, a ship is shown. The swirling bloom is at least 15 miles across, which means New York City's Manhattan Island could fit inside it with a little room to spare.

The swirling bloom is at least 15 miles across, which means New York City's Manhattan Island could fit inside it with a little room to spare.

Researchers are unsure what is causing the strange pattern.

'Note how the phytoplankton trace the edges of a vortex; it is possible that this ocean eddy is pumping up nutrients from the depths,' it said.

Nutrient-rich, cooler waters tend to promote more growth among marine plants and phytoplankton than is found in tropical waters, the agency added.

Though it is impossible to know the genus and species without sampling the water, three decades of satellite observations suggest that these green blooms are likely to be cyanobacteria (blue-green algae), an ancient type of marine bacteria that capture and store solar energy through photosynthesis (like plants).

WHAT ARE THE HEALTH RISKS OF AN ALGAE BLOOM? Technically called cyanobacteria, the ancient class of organisms that create the blooms are present nearly everywhere water is found, but thrive in warm, still bodies like lakes and ponds. Technically called cyanobacteria, the ancient class of organisms that create the blooms are present nearly everywhere water is found, but thrive in warm, still bodies like lakes and ponds. They also create a unique class of toxins, the impact of which on humans is only partly understood. Long linked to animal deaths, high doses of the toxins in humans can cause liver damage and attack the nervous system. In the largest outbreaks, hundreds have been sickened by blooms in reservoirs and lakes, and officials in some areas now routinely close bodies of water used for recreation and post warnings when blooms occur. But less is known about exposure at lower doses, especially over the long term. Small studies have linked exposure to liver cancer - one toxin is classified as a carcinogen, and others have pointed to potential links to neurodegenerative disease. Advertisement

Some of the greens also could come from diatoms, which are also rich in chlorophyll. According to news outlets, the Finnish Environment Institute (SYKE) has observed the recent bloom from the water and found it to be mostly cyanobacteria.

In recent years, the proliferation of algae blooms in the Baltic Sea has led to the regular appearance of 'dead zones' in the basin.

Phytoplankton and cyanobacteria consume the abundant nutrients in the Baltic—fueled largely by runoff from sewage and agriculture—and reproduce in such vast numbers that their growth and decay deplete the oxygen content of the water.

According to researchers from Finland's University of Turku, the dead zone this year is estimated to span about 70,000 square kilometers (27,000 square miles).

Polish health authorities said Wednesday they had closed scores of beaches along the country's Baltic Sea coast due to a massive toxic algae bloom triggered by a heat wave.

'Swimming is prohibited on eight beaches along the open sea and about twenty beaches in Gdansk Bay because of the appearance... of cyanobacteria,' Tomasz Augustyniak, health inspector for the northing Gdansk province, told AFP referring to blue-green algae.

In recent years, the proliferation of algae blooms in the Baltic Sea has led to the regular appearance of 'dead zones' in the basin.

'The algae is toxic and poses a health risk,' he said, adding that the week-old bloom was 'particularly intense' due to a long stretch of hot weather.

Polish television this week broadcast aerial footage showing a green carpet of algae covering the sea.

Run-off containing nitrates and phosphates from farm fertilisers and sewage have seeped into the Baltic, triggering large algal blooms in recent years, Augustyniak said.

Dying algae also triggers complex organic processes that suck the oxygen out Baltic waters leading to 'dead zones' where no marine life can exist.

Scientists termed oxygen loss in the Baltic 'unprecedentedly severe' in a study published this month in the European Geosciences Union journal Biogeosciences.

WHAT IS AN OCEAN DEAD ZONE? According to the NOAA, a dead zone the size of New Jersey has been identified in the Gulf of Mexico. A dead zone is an area of low oxygen that can kill fish and marine life. Nutrient runoff from the Mississippi River contributes to the dead zone. This nutrient pollution, mainly from agriculture and developed land runoff in the Mississippi River watershed, is affecting coastal resources and habitats in the Gulf by stimulating algal growth. Eventually, the algae decomposes, which uses up the oxygen needed to support life in the Gulf. This loss of oxygen in the water can cause the loss of fish habitat or force them to move to other areas to survive. It also leads decreased reproductive capabilities in fish species and a reduced average size of caught shrimp. Advertisement

They note that as a relatively small, shallow and enclosed sea, the Baltic has a very limited ability to flush out pollutants into the waters of the North Sea, making it an extremely vulnerable ecosystem.

Encircled by nine countries—Estonia, Denmark, Finland, Germany, Latvia, Lithuania, Poland, Russia and Sweden—the Baltic has an estimated 16 million people living along its shores.

A research team from Finland and Germany reported this month that oxygen levels in recent years in the Baltic Sea are at their lowest levels in the past 1500 years.

More frequent and massive blooms, combined with warming seas due to climate change, are making it harder for fish and other marine life to thrive in this basin.

The milky teal and white blooms are probably coccolithophores, which have tiny, chalky, calcium carbonate shells. The variations in brightness and color is related to both the concentration of phytoplankton and to the depth, as coccolithophores can grow as much as 50 meters below the water surface.

Research has shown that diatoms tend to dominate the waters of the Barents Sea in the early summer, when surface waters are well mixed.

As summer temperatures heat up and the water settles into warmer and cooler, fresher and saltier layers (stratification), coccolithophores start to take over.