CSIC Lights Up the Arctic Polar Night

Source and Courtesy CSIC Icebreaker Amundsen

CSIC communicated on the discovery of unknown -to the date photoactivity of Arctic planktonic marine bacteria. On February 25th the Spanish National Research Council CSIC explained that the discovery was made possible thanks to the work conducted on ground of the Arctic basin. The expedition which gathered over 350 scientists from 27 countries took to working in the iced ocean in six weeks shifts during the Polar Night months. 

CSIC simplifies by saying that there are bacteria that capture energy of the sun for survival mechanisms. PR protein is utilized in this vital cycle by the bacteria. “It is expectable that these bacteria express this protein when they need it, meaning, when there is sunlight, but not expected for the bacteria to be expressed in the darkness,” CSIC stated.

Scientists worked through the “Polar Night” months of little and no sunlight on board the Icebreaker Amundsen. The Icebreaker literally and intentionally trapped itself on the ice navigating into the waters somewhere in Quebec basins prior to the winter season and witnessed day after day how the ice surrounded the vessel.

The revelation of the study which was published at at the ISME Journal Magazine of the International Society for Microbial Ecology ISME in Nature´s main frame site questioned the established belief for the role of PR Protein in Arctic plankton -protein empowered through genetic mechanics to emit light.

The paper was written by scientist of the CSIC Institute of Sea Sciences of the University, University of Montreal Canada and University of Laval Canada which participated in the Circumpolar Flaw Lead System Study. The expedition took place in 2008. It took scientist 7 years to make the pàper public. 

CSIC explains that the work reached conclusions by analyzing genetic sequences of the Arctic microorganisms during the Polar Night. Astonishingly the study proved that the activity of photoactivity of the PR protein in December -when total darkness takes over the Arctic environment was higher than in the months of June and July. 

Prior to the study it was believed that the PR Protein proteorhodopsin served the role of orientation and growth. Sunlight orientation can only occur during the months of sun. 

The paper in complex scientific terms explains that there are variations of the PR Protein during the winter and summer seasons but that PR is always present. This presence even in the Polar Night months indicate that organisms makes use of the protein in different ways. UV light penetration during the Polar Nights while decreasing to lows is not completely absent. 

Carles Pedros Alio researcher of CSIC and main author of the paper added that the expression sustained by the photoactive proteins must provide bacteria with another function increasing their advantage to survive in the dark Polar Night.

“In the sunlit waters of the ocean, photoheterotrophy...is often mediated by proteorhodopsin PR…(allowing the) bacteria to capture photic energy for sensory and proton gradient formation cell functions. Here we show that PR is widely distributed among bacterial taxa, and that PR expression decreased markedly during the winter months in the Arctic Ocean. Gammaproteobacteria-like PR sequences were always dominant. However, within the second most common affiliation, there was a transition from Flavobacteria-like PR in early winter to Alphaproteobacteria-like PR in late winter,” the paper published at Nature explains. 

“Although genes for PR were always present, the trend in decreasing transcripts from January to February suggested reduced functional utility of PR during winter. Under winter darkness, sustained expression suggests that PR may continue to be useful for non-ATP (ATP as main energy sun cycle used by organism) forming functions,” the introduction of the paper states. 

The paper assures that functions could be “environmental sensing or small solute transport”, or “offer a competitive advantage” in the “harsh polar conditions and life of the microbial organisms of the Arctic basin.

The team gathered samples while trapped in the icea of the most inaccessible microorganism hidden beneath ice layers meters deep during the polar nights. The samples, their study and conclusions present new mysteries to be solved on strategies of survival, evolution, ecology and biodiversity as well as wider regional and global implications and uses. 

“Perhaps,” Pedros Alio ventures “bacteria make use of their light sensibility to approach marine animals such as fish, crustaceous or squid which are often bioluminescent”. This would provide them opportunity to approach the food webs during the time of the year were biological energy of the food webs is at its peak. 

Bioluminescence is often used for prey-predation behaviour. Additionally biochemical induced photoactivity serves identification purposes and reproduction in the marine realm. While the functions are yet to be revealed humankind gains insight on new Polar Night Lights which may have been shining in the Ocean for thousands or millions of years or perhaps even more.