British researchers have created the first large-scale map of the spread of microscopic algae on the coast of Antarctica. The images from space, there are almost 1700 sites, where the snow from them was green, BBC reports.
Green algae on the snow of Antarctica. Photo: Shutterstock
A team of scientists notes that the living organisms through photosynthesis, draw carbon dioxide from the atmosphere. They also play a key role in nutrient Cycling in one of the most remote regions of the Earth.
“They are primary producers at the beginning of the food chain. Any changes that occur with microalgae, the strongest impact on further stages,” said study leader Dr Matt Davey from the University of Cambridge.
“Although the amount of microalgae, which we are talking, small on a global scale, at the level of Antartica it significantly,” he said in interview Bi-bi-si.
Track green algae from space is a difficult task.
While on earth, to notice the changing color of snow is easy, but much more difficult to determine its orbit against the background surface with a strong reflecting ability.
Fortunately for researchers, high-precision detectors on Board the spacecraft of the European space Agency Sentinel-2 have increased sensitivity in that part of the spectrum that was needed for their observations.
The object of study was the Antarctic Peninsula — the strip of land that extends from the shores of the ice continent towards South America. Accumulations of algae are visible mainly on its Western shore, and two thirds of them — on the Islands scattered along the coast.
A total of microalgae cover an area of almost two square kilometers. This means they annually consume about 500 tons of carbon dioxide, which, as scientists have calculated, corresponds to the emissions from 875 thousand the average car journey in Britain.
In fact, the figures are incomplete, because the detectors Sentinel-2 differ only in green microalgae and missing the red and orange, because it is not sensitive enough in this part of the spectrum.
“Sad, because we have demonstrated how it works on the equipment of the WorldView-3 satellite, but unfortunately, shooting him is too expensive. But Sentinel is free,” explains Dr. Andrew gray working in the University of Cambridge and spectroscopic laboratory NERC in Edinburgh.
The problem will be solved as they are launched more satellites with open access to data, he added.
Antarctic microalgae was first described by the expeditions of the 1950-ies and 1960-ies. They look beautifully when dyed the snowy slopes of broad colored bands, contrasting with the surrounding white. It is a popular spectacle and a story for the tourists from the cruise ships.
For the prosperity of these organisms need a sufficient amount of water in the liquid state, so they meet in the snowy areas where the temperature drops far below zero.
They also depend heavily on the availability of seals, penguins and Antarctic birds such as Skuas and Dominican gulls, whose droppings are a source of algae need nitrogen and other substances.
I wonder what will happen with the algae, if the Antarctic warms. The temperature on the Peninsula is growing rapidly since the second half of the last century and climate models predict that this trend will continue in the coming decades.
A field of seaweed in the Islands, slightly protruding need sea level, may disappear followed by the snow. On the other hand, the algae will open up new opportunities on the mainland and in more elevated areas.
“Probably, there are many different types of algae, each of which occupies its own niche. Some live on the surface of the snow, others slightly better, and their number will vary depending on temperature, says Professor of biology from Cambridge, Allison Smith. But we don’t know their number will increase or decrease, and does not learn without constant surveillance”.
In a study published in the journal Nature Communications, was also attended by experts of the British center for the study of the Antarctic and the University of Edinburgh.