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Scientists have discovered a significant proliferation of seaweeds extending over most of the Atlantic Ocean, from the west coast of Africa to the Gulf of Mexico. The bloom, dubbed the Great Sargassum Belt of the Atlantic, first appeared in 2011 and has become an almost annual phenomenon, fueled in part by an influx of nutrients drawn into the sea by the deforestation and agriculture in the Amazon, researchers reported in the newspaper Science.
Prior to 2011, most sargassum plants in the ocean were found in small clumps around the Gulf of Mexico and the Sargasso Sea. But in 2011, satellite images showed a nearly constant series of plants extending across the entire tropical Atlantic Ocean. In subsequent years, the algae belt became longer and thicker. Last year, the belt contained more than 20 million tonnes of Sargassum, more than 200 fully loaded aircraft carriers, according to NASA.
"I can say that the belt will most likely be a new normal," said in a statement Chuanmin Hu, a scientist in marine science at the University of South Florida.
Sargassum provides critical habitat for marine animals such as turtles, crabs, fish and birds, while producing oxygen via photosynthesis. In a press release, scientists warned that too much algae might "prevent some marine species from moving or breathing," could choke off coral and seagrass when it s & rsquo; Sank to the bottom of the ocean and could release hydrogen sulphide gas when she washed on the ground. Several countries, including Barbados, have declared situations of national emergency due to the amount of algae accumulated on their beaches and detrimental consequences for the tourism industry.
"The magnitude of these blooms is really huge," said Woody Turner, head of the ecological prediction program at NASA's headquarters in Washington.
Hu and his colleagues discovered that several factors were responsible for the recent proliferation of algae: a large seed population left by previous bloom, nutrients from West Africa in winter and a contribution new nutrients from the Amazon. Sarargas also grow abundantly only when salinity and surface temperatures are normal. "The chemistry of the ocean must have changed so that the flowering becomes so uncontrollable," said Hu. Scientists have discovered that deforestation rates in the Amazon – and the subsequent expansion of agriculture and the use of fertilizer – in particular contributed to fuel larger blooms. ;algae.
"The biogeochemistry of the Earth's oceans is changing in response to natural and human forcings," said Paula Bontempi, Acting Deputy Director of NASA's Earth Sciences Division, in a statement. "The Atlantic sargassum belt suggests that we may be seeing ecosystem changes in our ocean that could have a significant impact on the marine organisms and ecosystem services upon which humans depend."
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