Antarctic Fungi Provides a Window into the Past and Future

Most life forms are unable to survive the mind-numbing temperatures on the polar continent of Antarctica, which can reach minus 90 degrees Celsius. In this extreme climate, however, researchers have found snow and ice harbors fungi specially adapted to thrive. A new book, Fungi of Antarctica, edited by Luiz Henrique Rosa, was published on June 19 and features a chapter “Fungi in Snow and Glacial Ice of Antarctica,” which identifies fungi in the snow and ice of the continent and reviews their features, functions, and biotechnological applications.

The 28 different species of fungi indexed in the chapter were likely transported to the continent by air currents, decanted from the atmosphere through precipitation, and settled on the snow and ice.

Graciéle Cunha Alves de Menezes is a scientist in the microbiology department at the Federal University of Minas Gerais in Brazil and is the lead author of the chapter. She says the cold-loving fungi might provide key information regarding the microbial compositions of the planet in the past.

Still of Antarctica surrounded by sea ice taken on October 10, 2004 (Source: NASA).

Antarctica has an area of 14 million square kilometers, of which about 99 percent is covered by ice and snow. The study of Antarctic microorganisms has attracted considerable interest since the 1960s because of its extremely harsh climatic conditions, though studies have been few and far between. Antarctica’s remote location presents logistical difficulty that has inhibited research on the microbial diversity locked in the continent’s ice.

Researchers found the fungi broadly distributed in the different ice layers and ecosystems of Antarctica. “Both cold substrates, snow and ice, harbor interesting fungal species living at the edge of life in terms of temperature, low nutrient availability, and high exposure to ultraviolet radiation,” the authors wrote. Two species of Antarctic fungi, which were not part of the study, recently survived 18 months on the International Space Station, with more than 60 percent of cells intact.

The fungal communities also provide the nutritional foundation for surrounding glacial ecosystems––not to mention the fermentation of many human foods (one Canadian baker is specifically gathering Arctic yeasts from which to make sourdough bread).

A team of researchers arrives to prospect the collection area on Coppermine Peninsula located on Robert Island, part of Antarctica’s Shetland Islands (Source: Graciéle Cunha Alves de Menezes).

Not only do the extremophiles provide a backward-looking telescope into the planet’s first primitive life forms, they hold promising features for innovations in biotechnology. “Fungi adapted to the extreme conditions of Antarctic snow and ice may exhibit genetic and biochemical pathways to produce antifreeze compounds, tolerance to low nutrient availability, and photoprotective activity,” De Menezes said.

Because ice formation within an organism’s cellular walls is lethal, fungi have developed strategies to protect themselves from freezing, including the production of antifreeze proteins. The authors say the enzymes that the fungi produce at low temperatures hold promise for advances in biofuel technology, for one. Their diverse and high enzymatic activity in extreme cold also has potential in other biotechnological applications, including increased energy efficiency in large scale commercial bioprocesses––the process that uses complete living cells or their components to create products.

De Menezes told GlacierHub that the fungi’s various biological processes generate substances that can be isolated to manufacture drugs, vaccines, herbicides, and natural fungicides for use in agriculture and antifreeze proteins, pigments, and cold-active enzymes that could be used in the food industry. The pigments produced by the fungi have great potential for use in the photoprotective cosmetics and the textile industry as a natural dye, she added.

Alternaria alternata is one of the fungi species researchers identified in the Byrd region near the South Pole (Source: WikiCommons).

Masaharu Tsuji is a postdoctoral fellow at Japan’s National Institute of Polar Research, who was not involved in the writing of the book’s chapter on Antarctic fungi. “Antarctica is considered to be close to the condition of the primitive global environment,” Tsuji told GlacierHub. “Understanding the role of Antarctic ecosystems and fungi in Antarctica is very important in understanding how ecosystems have changed on the past Earth and how ecosystems will be changed on the future Earth.”

Glaciers, ice sheets, and sea ice are melting rapidly due to warming ocean and atmospheric temperatures. “If climate change continues, fungi currently inhabiting Antarctica will lose their habitat because they are specialized for living in polar environments, like the Arctic and Antarctica,” Tsuji said. “In other words, fungi on ice or glaciers in Antarctica are endangered species.” If the world needed another rapidly dwindling biodiversity hourglass, it has found one in Antarctic fungi.

What An Antarctic Island Tells Us about Mars

For several years, researchers have worked to determine how life can be sustained in extraterrestrial space, known for conditions of extreme heat and cold. A recent study in the journal Extremophiles, conducted on Deception Island in Antarctica, provides answers to some of these questions.

Pendulum Cove, Deception Island, Antarctica (Source: Delphinidaesy/Flickr).

At Deception Island, both volcanoes and glaciers lie in close proximity, creating regions of prominent temperature differences over a short distance. The extreme conditions on the island range from 98 to 0 degrees Celsius due to the presence of active fumaroles (openings near the volcano), where the temperatures reach values of 100 degrees Celsius, and glaciers, where temperatures drop to 0 degrees Celsius. The close proximity of volcanoes and glaciers makes Deception Island an interesting analogue for extraterrestrial environments, including Mars’s extinct volcanoes and Enceladus’s cryovolcanoes.

This polar location allowed researchers to recover microorganisms that have the ability to survive under very hot conditions beyond their growing range of temperature. The study explored the microorganisms surviving in these conditions and tested their survival potential in astrobiological conditions.

To isolate the microorganisms surviving in these extreme environments, the scientists collected sediment samples from the volcano on Deception Island during the XXXII Brazilian Antarctic Expedition from December 2013 to January 2014 at the geothermally active sites of Fumarole Bay and Whalers Bay.

Deception Island, Antarctica (Source: Melissa Scott/Flickr).

Through DNA-sequencing techniques, scientists estimated the total number of bacterial cells in the sediment. To isolate microbes that have the ability to survive in extreme conditions, the samples were incubated in two different temperatures, 4 degrees Celsius and 60 degrees Celsius. The samples were allowed to grow for about two weeks. A total of 147 colonies were successfully obtained from these procedures, and they were subjected to further molecular analyses to determine the species and the genera of the microorganisms.

In addition, the samples were subjected to ultraviolet radiation that is present on Mars, called UV-C radiation. UV-C radiation, although not present on Earth, composes a significant proportion of UV spectra on the Martian surface, due to the rarified atmosphere of the planet.

On top of the volcano crater on Deception Island (Source: staigue/Flickr).

Scientists from the study found that the microorganisms were able to survive these conditions despite the fact that these range of temperatures were beyond the range in which they normally grow. The study also found that these microorganisms adapted to surviving under these temperatures by forming spores around their membranes, which enabled them to resist the extreme range of temperatures. These structures suggested to the researchers that there could be a similar adaptation strategy to enable the survival of microbial life on Martian surfaces.

The study provided interesting insights into strategies deployed by microorganisms to survive in conditions that resemble the Martian surface. The initial data from the study suggest the thermophiles isolated by the researchers have the potential to be further explored in astrobiological studies.

Sruti Devendran holds a Master’s degree in Climate and Society from Columbia University. She did her undergraduate degree in biotechnology in India. She is curious about the potential possibility of life in extraterrestrial space. She enjoys writing and cares about issues affecting low income communities impacted by climate change.