Giant viruses attack microscopic algae in arctic epishephal lake

The analyzes were carried out in Cycling Lake Mile FjordIt is about 800 km from the North Pole. However, we must begin by explaining what a lake of this type is. Lake Epishephal It is a natural freshwater reservoir, created by blocking the flow of water from a fjord through an ice shelf. Fresh water flowing from above, due to differences in density, forms a layer on the surface of the most dense saline sea water. Lakes of this type are unique areas that do not have a permanent bottom – the bottom is where fresh water and salt water meet. In short: it is a layer of fresh water “trapped” between the ice on the surface and the salt water at the bottom.

New research suggests Mile Fjord is dominated by microbes and is ‘on the cusp’ of it Global warming and climate change. In addition, scientists have found An unusual ‘viral community’ In the fresh waters of the lake, its diversity is much greater than that of the “community” that lives in low salt water. This type of lake can exist for centuries and can create rare and unique ecosystems.

Scientists took water samples from Lake Mile Fjord and then sequenced the DNA of the microbes that were found. They identified all kinds of viruses, including “giant” viruses called Megaviricetes, which are several times larger than ordinary viruses – they are the size of bacteria.

The distinguishing feature of viruses, Thaler says, is that they are smaller than even the smallest known bacteria and carry only a few genes. However, over the past 20 years, scientists have found that “Giant” viruses They are relatively similar to bacteria in size and genome.

Researchers do not yet know how most viruses affect the microscopic algae that live in this amazing lake. The scholars write in their article:Viruses are key to understanding polar aquatic ecosystemsdominated by microorganisms. However, studies of viral communities are difficult to interpret because the vast majority of viruses are known only from sequenced fragments, and their taxon, host, and genetic stock are unknown.[…] Viruses also indirectly affect the community (algae liberator) by affecting the host’s metabolism.

– Epishephal lakes were more common in the Arctic, but now they are extremely rare. If the ice dam bursts – as it has in other fjords – then Lake Milne Fiord Epishelf You will be lost forever Thaler said.