A new study reveals that giant icebergs are defending the planet against climate change.
Authors of the study have analyzed satellite data from 2003 to 2013 tracking 17 giant icebergs, measuring over 11 miles in length from the Antarctic Ocean. The study has been published in Nature Geoscience journal.
According to the authors, as a giant iceberg passes through the waters the levels of chlorophyll increase over a radius between four to ten times the length of the iceberg. The increased levels persist for more than a month.
The same effect has been observed in smaller icebergs too but the area of influence is about ten times smaller for icebergs with lengths under one kilometer.
Grant Bigg of the University of Sheffield, UK and co-author of the paper claims that the plums of phytoplankton produced by giant icebergs are much bigger than scientists were expecting. This is because the meltwater releases high concentrations of iron which fertilizes the phytoplankton encouraging its production.
As a result, giant icebergs have a major role in the carbon cycle of the Southern Ocean. This is because the phytoplankton in oceans acts like plants and trees act on earth. They grow through a process of photosynthesis, absorbing large quantities of carbon dioxide and releasing oxygen. However, then it dies, the phytoplankton sinks to the bottom of the ocean releasing back the carbon.
According to professor Bigg, the presence of about 3,000 giant icebergs at the same time in the Southern Ocean has allowed scientists to calculate the amount of carbon “eaten” by the phytoplankton which appeared as a result of the nutrients released by the giant icebergs’ meltwater rich in nutrients.
Estimates say that about 10 to 20 percent of the vertical carbon rate going from the surface to the bottom of the ocean is the result of the phytoplankton created by the giant icebergs.
If the calving of giant icebergs will increase during this century as scientists predicted the negative impact on the carbon cycle might be devastating, a lot more important than scientists initially thought.
According to Dr. Richard Kirby, a plankton specialist who wasn’t involved in the current study, the phytoplankton living at the surface of the ocean has influenced the carbon released in the atmosphere along the history of our planet, controlling the concentration of the greenhouse gas.
This study shows that scientists still have a lot to discover regarding the phytoplankton and its importance for our planet but also about the way in which it is affected by the climate change.
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