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.

Roundup: Subglacial Drainage, Extremophiles and Yellowstone Name Change

Subglacial Drainage Under a Valley Glacier in the Yukon

From The Cryosphere: “The subglacial drainage system is one of the main controls on basal sliding, but remains only partially understood. Here we use an 8-year dataset of borehole observations on a small, alpine polythermal valley glacier in the Yukon Territory to assess qualitatively how well the established understanding of drainage physics explains the observed temporal evolution and spatial configuration of the drainage system.”

Read more about the study here.

Kathleen Lake Yukon on GlacierHub
Kathleen Lake in Klaune National Park, Yukon (Source: Creative Commons).

 

Extremophiles at Deception Island Volcano in Antarctica

From Extremophiles: “Deception Island is notable for its pronounced temperature gradients over very short distances, reaching values up to 100 °C in the fumaroles, and subzero temperatures next to the glaciers. Our main goal in this study was to isolate thermophilic and psychrophilic bacteria from sediments associated with fumaroles and glaciers from two geothermal sites, and to evaluate their survivability to desiccation and UV-C radiation. Our results revealed that culturable thermophiles and psychrophiles were recovered among the extreme temperature gradient in Deception volcano, which indicates that these extremophiles remain alive even when the conditions do not comprise their growth range.”

Learn more about extremophiles here.

Image of an extremophile, Tardigrades, which are found in a range of extreme environments (Source: E. Schokraie et al./Creative Commons).

 

Native Americans Seek to Rename Yellowstone Peak

From The Guardian: “A valley in Yellowstone National Park in Wyoming, formed by a glacier, may get a new name. Hayden Valley is glacial, dating back to the last Ice Age. It was named after a surveyor, Dr. Ferdinand V. Hayden who advocated removing Native Americans from the region. The Great Plains Tribal Chairman’s Association, comprising tribal chairmen of 16 Sioux tribes from Nebraska and the Dakotas, is pursuing an application to change the name of Hayden Valley to Buffalo Nations Valley.”

Find out more about the news here.

Hayden Valley Yellowstone on GlacierHub
Hayden Valley (Source: Yellowstone National Park).

Brittle Stars, Sea Urchins, and Starfish

The increase of heat-trapping greenhouse gases in Earth’s atmosphere is warming the Antarctic Peninsula at a unprecedented rate. A recent study from Angulo-Preckler et al. in Continental Shelf Research explores whether significant decreases in sea ice and melting glaciers in the waters west of the Antarctic Peninsula favor some species of marine life and harm others. Among the species which call the waters home, the authors of this study focus on echinoderms, an invertebrate phylum that includes starfish, sea urchins and brittle stars.

Accounting for approximately 45 percent of biomass on the ocean floor west of the Antarctic Peninsula, echinoderms live between the intertidal zone and the sea floor. With no heart, brain or eyes, echinoderms use tentacle-like structures with attached suction pads on their appendages to slowly traverse underwater surfaces. As filter-feeders, echinoderms grab their prey with tentacles, consuming it through a mouth located on their underside. Although echinoderms already live in an environmentally challenging location, with water temperatures reaching 0°C and below, melting glaciers are adding an additional level of complexity to their ecosystem.

A seafloor community near King George Island in the South Shetland Islands of Antarctica (Source: Courtesy of Ricardo Sahade/Images not for reuse).
A seafloor community near King George Island in the South Shetland Islands of Antarctica (Source: Courtesy of Ricardo Sahade/Images not for reuse).

For example, on Deception Island, a volcanically-active island in the South Shetland Islands archipelago, physical disturbance from the volcano and glacier retreat are causing alterations to the ecosystem. Deception Island’s volcano last erupted in 1970, yet volcanic ash from that eruption and previous eruptions settled on nearby glaciers. As the glaciers melt, volcanic ash travels from glacial surfaces to the marine waters below.

In turn, mixing marine waters distribute volcanic ash to depths where echinoderms dwell in a process called sedimentation. This impacts the survival of some echinoderms as they are incapable of thriving under high levels of sedimentation. High sedimentation is problematic for certain species because the additional material prevents them from easily inhabiting crevices between rocks and sponges.

Deception Island and Port Foster (Source: Apcbg/Wikimedia Commons).
Deception Island and Port Foster (Source: Apcbg/Wikimedia Commons).

Port Foster, a bay encompassed by Deception Island, is fed by the surrounding melting glaciers. Angulo-Preckler et al. examined eight different locations in the Deception Island bay, at both 5 meters and 15 meters, to determine a relationship between high sedimentation rates and the number of echinoderms. The study found three dominant echinoderms – the brittle star (Ophionotus victoriae), the Antarctic sea urchin (Sterechinus neumayeri) and the Southern Ocean starfish (Odontaster validus) – are coping well to the high sedimentation rates, at the expense of other echinoderms.

The researchers found that the opportunistic brittle star and sea urchin are now dominating areas of Deception Island Bay by replacing other echinoderms, such as the sea cucumber. Where there was once a large variety of species, there are now just three main echinoderms. This reduction in biodiversity has implications for the health of the ecosystem.

Starfish near the South Shetland Islands, Antarctica (Source: Courtesy of Ricardo Sahade/Images not for reuse).
Starfish near the South Shetland Islands, Antarctica (Source: Courtesy of Ricardo Sahade/Images not for reuse).

High ash sedimentation from the volcano and high sedimentation rates due to the retreat of glaciers could decrease biodiversity levels at Port Foster by forcing other species out of their habitat. Since the last eruption, many of the echinoderms that once flourished in the area have now disappeared. As the region continues to warm, research suggests that increasing sedimentation from melting glaciers could continue to impact the communities of the intertidal and benthic zone of western Antarctica.

Ricardo Sahade, an Antarctic ecologist from the National University of Córdoba in Argentina, confirmed to GlacierHub that “coastal ecosystems experiencing glacier retreat can be threatened by increased sedimentation.” More sedimentation and melting glaciers change the composition of echinoderm habitat. Further research will provide fuller details on whether higher sedimentation reduces biodiversity in this marine ecosystem. Even now, it is evident that disturbances from retreating glaciers are changing the Antarctic ecosystem and the habitat it provides.