Scientists have measured the largest seaweed bloom on record as of today. It stretches close to 8,850 kilometers across the Atlantic Ocean and is expected to be made up of 20 million metric tons of Sargassum Algae. The study has been published in Science journal.
The weight is equivalent to that of 200 fully loaded aircraft carriers. It is called the Great Atlantic Sargassum belt and it is continuously expanding. It receives the nutrients from the Amazon river on one side and the West African coast on the other side, part of which is due to the increased deforestation and use of fertilizers.
As per the satellite images and data received from NASA as well as the samples which were collected on the field, the researchers have identified a tipping point which dates back to 2011. From 2011 onward there has been a major bloom almost every year and the trend continues even today which stretches from West Africa to the Gulf of Mexico. Scientists have associated the increase in deforestation and use of fertilizers in Brazil and the Amazon which began at the start of the decade however this is not a clear cut association. The researchers are not in a position to confidently put forward the cause of this bloom but are confident that it will not go away anytime soon.
There are preliminary evidence and limited field research which cannot confirm their hypothesis as they need more data as well as research according to study leader Chuanmin Hu from the University of South Florida. The belt may have a new normal based on 20 years of data. What could this mammoth bloom do to our oceans is a question waiting to be answered and that seaweed blooms are not necessarily bad for the ocean as this provides habitat for turtles, crabs, fish and birds and produces oxygen for marine life.
Too much algae can cause problems by restricting movement and breathing of certain marine species and if the seaweed dies it can choke the corals and seagrass due to its huge volume. It produces a rotten egg smell due to the presence of hydrogen sulfide when left rotting and can impact the health of residents and tourists. The size of bloom peaks between April and July before slowly reducing but leftover seeds contribute in the next summer.
Many factors like salinity and temperature as well as nutrient levels of all the years play a major role in the sargassum growth. More nutrients from the Amazon and rising of sea levels off West Africa contribute more nutrients. Knowing the extent of bloom the researchers will further investigate its causes and consequences on precipitation, ocean currents and humans.