Whence in spring almost millions of microalgae appear in almost sterile cold water? What attracts them is the narrow five-kilometer strip between Arctic cold and warmth of the Atlantic? And why is reduction of ice cover leading to a decrease in biological productivity? Scientists of Murmansk Marine Biological Institute are looking for answers to these questions. The other day they summarized results of last year's expedition to high latitudes.

Cold is required

55 days at the boundary of the Arctic ice, hundreds of samples and measurements, a year to analyze the data brought surprising results. It would seem that the warmer the water, the more life it should contain. But collected information refutes this stereotype.

"We wanted to see how the ice edge change affects productivity of the Barents Sea," explains Pavel Makarevich, the first deputy director for science at Murmansk Marine Biological Institute. - It's no secret that ice cover in autumn-winter period in the Barents Sea has changed a lot. The edge is now much more northeast than it was 30-40 years ago. Forecasts of our foreign colleagues were based on calculations. It follows that the bioproductivity should increase with decreasing ice area. We agreed with this until we got the observational data. Now we have almost unanimous opinion: when ice retreats, bioproductivity does not increase in any case, but most likely it even decreases.



Why is attention of scientists riveted to the water area at the ice edge? It's simple. Flowering microalgae in spring give the Arctic seas from 60 to 80 percent of the primary organic matter. This is the beginning of food chain, on which well-being of all marine inhabitants largely depends throughout the year. By the way, the phenomenon of high bioproductivity zone formation is known to science. But its driving forces are still a mystery.

- This is some kind of common mechanism. At the ice edge, all phytoplankton organisms for some reason feel better than 20 kilometers to the south, - says the researcher of the plankton laboratory Anatoly Oleinik. - It is known that in winter microalgae are almost absent in water. And suddenly in spring there are millions of them in each liter. There are two hypotheses. The first - spores of algae from the bottom (from a 300-meter depth), somehow, without noticeable vertical currents rise up and start to blossom. The second - they fall into water from melting ice. There really are a lot of them. It is a fact. But if you compare the amount of ice (and in the Barents Sea it is a maximum of a meter layer) with flowering volumes, then there are doubts about this assumption.

Where did viruses disappear?

Sunlight and mineral salts are what microalga need for synthesis of primary organic matter. Perhaps, melting ice, which dissolves salty water, plays its role in the outbreak of life. To understand ecological mechanism of the phenomenon, the expedition collected data on various characteristics - temperature, salinity, chemical composition of water, number of microalgae and even bacteria and viruses in it.

"I was surprised at the very uniform distribution and low number of vireoplankton," says Marina Venger, a junior researcher. - We saw this for the first time. From one station (sampling site - ed.) to another, changes were very insignificant. There are more viruses in samples even in the polar night.


It must be said that the expedition fell on an anomalous period, from the ice situation point of view. Clear water is rare, as far north as last spring in April. The last time similar conditions were in 1995.

"Last year, a very powerful flood of Atlantic waters was observed," explains the Deputy Director of MMBI for Science Denis Moiseev. - Along with atmosphere and winds influence, this was one of factors that the ice edge in April, during its maximum development, was so high. Now we would not have got there, only with an icebreaker. By the way, mostly our young staff was on board. They worked under the most severe conditions: wind, fog, snow, frost. Floating ice floes were around. They had to be driven off by the hoods, so that they do not interfere with instruments.

Back to the fundamental science

Extreme conditions in which it was necessary to collect materials are justified by scientific results. There were no such data on the Barents Sea so far. In addition, for the institute, the expedition to the ice edge was a return to fundamental works.


- Since the 90s, fundamental science has not been practically funded. Therefore, we focused on applied work - orders of large corporations, such as Rosneft and Gazprom. The situation began to change three years ago. And in 2016 we received very serious money, - comments Pavel Makarevich, the First Deputy Director for Science of Murmansk Marine Biological Institute. - We were able to organize several expeditions, including to the ice edge, which was fully funded by the Federal Agency of Scientific Organizations. And, naturally, studies were extremely fundamental.

Fundamental - does not mean not applicable in ordinary life. Understanding of spring processes at the edge of the Arctic ice will help, for example, predict the change in commercial species number of the Barents Sea. By the way, this year federal funding will allow the institute to organize two expeditions with a total duration of 65 days. The first - to Spitsbergen shores - starts in May. Apart from MMBI scientists, researchers from other scientific centers of Russia will also be exploring the Arctic archipelago aboard of Dalnie Zelentsy.

Published: Murmansk Vestnik on 26/04/2017