Exception or Rule? The Case of Katla, One of Iceland’s Subglacial Volcanoes

Katla Volcano in Iceland on GlacierHub
Grasslands in the foreground, with Katla covered by clouds in the background (Source: Inga Vitola/Flickr).

A recent study in Geophysical Research Letters about Katla, a subglacial volcano in Iceland, revealed that Katla emits CO2 at a globally important level. Previously, Katla’s CO2 emissions were assumed to be negligible on a global scale.

In this study, conducted by Evgenia Ilyinskaya, a volcanologist at the University of Leeds, and her associate researchers, airborne measurements were carried out using gas sensors to obtain CO2 source and emission rates for Katla. In addition, the researchers used atmospheric dispersion modeling to identify the source of gas emissions and calculate gas emission rates.

A CO2 emission rate of 12-24 kilotons per day is considered significant on a global level. Ilyinskaya and coauthors’ measurements taken on the western side of Katla indicated significant CO2 flux levels in both 2016 and 2017. Also in 2017, the researchers identified another significant source of CO2 emissions, Katla’s central caldera.

Katla 1918 eruption on GlacierHub
Katla’s last eruption was in 1918 (Source: Creative Commons).

Emissions estimates that are both accurate and representative for subglacial volcanoes are challenging to obtain. According to the study, this is because these volcanoes are hard to access and “lack a visible gas plume.” The researchers noted that CO2 flux measurements are available for just two of Iceland’s 16 subglacial volcanoes, and these measurements indicate only modest emissions estimates. Further, these measurements were obtained by analyzing gas content dissolved in water, a method which likely underestimates CO2 flux. Ilyinskaya and her coauthors used a more precise estimate in this study than previous methods, such as the one discussed above.

Total CO2 emissions from passively degassing subaerial volcanoes are currently estimated at 1,500 kt/d, and CO2 flux is currently estimated at 540 kt/d. The results Ilyinskaya and the other researchers found indicate that Katla’s CO2 emissions would account for 2-4 percent of that total. However, they stipulated that subglacial volcanoes were underrepresented in the data collected to create this estimate. Measurements from 33 volcanoes were extrapolated to cover CO2 emissions of 150 volcanoes, but only three of the 33 were subglacial volcanoes.

Myrdalsjokull glacier covering Katla volcano on GlacierHub
View of the Myrdalsjokull glacier, which covers Katla (Source: Zaldun Urdina/Flickr).

Regarding Katla, Ilyinskaya and coauthors identified two possible implications of this information. First, Katla could be an exceptional emitter. Katla’s large size and recent heightened seismic activity make this possibility more plausible. But the researchers pointed out that measurements must be conducted at other subglacial volcanoes before this possibility can be corroborated.

A second possibility is that Katla’s CO2 emissions are representative of what other subglacial volcanoes emit. If this is true, estimates of CO2 emissions from subglacial volcanoes are grossly underestimated at present. Once measured properly, these volcanoes would make a much more significant contribution to global volcanic CO2 emissions. Currently, subaerial volcano CO2 emissions are assumed to be just 2 percent of anthropogenic CO2 emissions totals, but this could change with improved measurement practices.

Myrdalsjokull glacier above Katla volcano on GlacierHub
Atop the Myrdalsjokull glacier, with Katla beneath it (Source: Adam Russell/Flickr).

In the context of climate change, it is important that CO2 emissions from natural sources are adequately quantified alongside anthropogenic sources. As the results of this study suggest, subglacial volcanoes such as Katla could have emissions contributions that are more significant than originally thought. Ilyinskaya and her fellow researchers stressed the vital importance of conducting similar measurements at other subglacial volcanoes to ensure that their CO2 emissions are properly quantified in global estimates.

Please follow, share and like us:
error

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).
Please follow, share and like us:
error

GlacierHub News Report 05:24:18

GlacierHub News Report 05:24:18

 

The GlacierHub News Report is a bi-monthly video news report that features some of our website’s top stories. This week, GlacierHub news is featuring the “Doomsday” glacier, a new study on GLOFS and climate change, subglacial lakes in Canada, and some beautiful aerial shots of the Rockies!

 

This week’s news report features:

 

Project Aims to Better Understand “Doomsday” Glacier

By: Andrew Angle

Summary: The largest joint United States-United Kingdom Antarctic project since the 1940s was announced at the British Antarctic Survey in Cambridge. The International Thwaites Glacier Collaboration or ITGC will focus on the Thwaites glacier of West Antarctica, one of the world’s largest and fastest melting glaciers. A five-year collaboration between the U.S. National Science Foundation and U.K. Natural Environment Research Council worth $25 million will include six scientific field studies with over 100 scientists to analyze changes to the Thwaites and surrounding ocean.

Read more here.

 

Will Climate Change Be Responsible for More Glacial Lake Outburst Floods?

By: Natalie Belew

Summary: How certain is it that climate change increases the frequency and severity of glacier lake outburst floods or GLOFs? It turns out the answer is a bit complicated and the subject of a new study published in The Cryosphere. This recent study provides the first global assessment of the problems involved in developing a robust attribution argument for climate change and GLOF events.

Read more here.

 

Unprecedented Subglacial Lakes Discovered in the Canadian Arctic
By: Jade Payne

Summary: A joint study published last month in Science Advances predicted the presence of two hypersaline subglacial lakes. The lakes are located on either side of the east-west ice divide of the Devon Ice Cap, an ice cap located in Nunavut, Canada. The lakes could represent significant microbial habitats that could be used as analogs to study the conditions for potential life on other planets.

Read more here.

Capturing the Glaciers of the Rockies

By: Brian Llamanzares

Summary: In lighter news, Garrett Fisher, a writer, photographer and adventurer, recently set out to capture the beauty of the Rockies. To do so, he flew an antique plane across the sky for aerial views of the last remaining glaciers in Colorado, Wyoming, and Montana. He was inspired by the need to document the glory of the Rockies before the glaciers disappear completely. His photos from the trip can be found in his recently published book, “Glaciers of the Rockies,” which features his collection of 177 carefully curated photos.

See some of the images here.

 

Video Credits:

Presenter: Brian Poe Llamanzares

Video Editor: Brian Poe Llamanzares

Writer: Brian Poe Llamanzares

News Intro: YouTube

Music: iMovie

Please follow, share and like us:
error

Unprecedented Subglacial Lakes Discovered in Canadian Arctic

Environments with the power to unlock the secrets of other worlds have been found several hundred meters beneath the ice of the Canadian Arctic. A joint study published last month in Science Advances predicted the presence of two hypersaline subglacial lakes on either side of the east-west ice divide of the Devon Ice Cap, an ice cap located in Nunavut, Canada, known for its rugged terrain of both mountain ridges and bedrock troughs. These are not only the first subglacial lakes to be found in the Canadian Arctic but also the first hypersaline subglacial lakes reported to date, each estimated to be around 5 and 8.3 square kilometers.

A map of the Devon Ice Cap and subglacial lake locations (Source: Science Advances).

The lakes, which are described as “unprecedented” in the study, are of great interest to researchers for their unique characteristics: both are hypersaline and spatially isolated. This isolation from outside influences may reach back 120,000 years ago, when the lakes were covered by glacial ice.

The lakes could represent significant microbial habitats, which could be used as analogs to study the conditions for potential life on other planets. Specifically, the study states that these lakes could represent similar environments to the potential brine bodies within Europa’s ice shell or Martian polar ice caps.

“Because these subglacial systems are isolated for tens of thousands of years, they are excellent candidates to explore life processes in extreme conditions,” states Alexandre Anesio, a professor and researcher at the University of Bristol who studies the biogeochemistry of the cryosphere. He sees this opportunity as “one of the best ways to explore the limits of life on other planets.”

The newfound potential of these lakes came as a shock, Anja Rutishauser, one of the study’s researchers, told GlacierHub. “The original research goal was to better understand these basal conditions of Devon Ice Cap, as they largely affect ice dynamics and how ice flow might change under future climatic conditions. We expected to find subglacial water signatures in the faster-flowing marine-terminating outlet glaciers, but certainly not in the center of Devon Ice Cap.”Rutishauser added that the ice cap was expected to have ice frozen to the ground, not liquid water or entire subglacial lakes.

A UTIG research scientist operating radar instruments inside a DC-3 aircraft during a survey flight over Devon Ice Cap (Source: Anja Rutishauser).

The discovery was made when the researchers analyzed radio-echo sounding measurement data. Models further analyzed the basal ice temperature. It measured 10.5 degrees Celsius, which led to the conclusion that the hypersalinity was significantly depressing the freezing point temperature. Further, the study found that this is in “agreement with surrounding geology, situated within an evaporite-rich sediment unit containing a bedded salt sequence,” the likely source for the salt. The exact origins of the subglacial lakes and the processes that formed them remain unclear, but similar bodies can offer clues to the specifics of the Canadian lakes.

According to the study, Taylor Glacier in Antarctica contains the most comparable subglacial fluid to the Canadian lakes, with similar temperature and salinity measurements. However, it is sourced from ancient marine water and not spatially isolated. Taylor Glacier’s outflows have been found to have active microbial communities, which leads researchers to believe the same is possible in the Devon Ice Cap.

Taken from the DC-3 aircraft during transit and aerogeophysical survey flights over Canadian Arctic ice caps and glacier (Source: Anja Rutishauser).

Many subglacial lakes in Antarctica and Greenland share other similarities with the Canadian lakes, further bolstering the study’s evidence. “Almost all the effort on subglacial lake exploration is concentrated in Antarctica, but this study reveals that there are other excellent locations for subglacial lake exploration,” according to Anesio. However, he believes further exploration is no trivial task considering the engineering challenge to drill cleanly into a subglacial lake without the risk of contaminating it. “However, it is certainly worth a try,” he said.

This is precisely how the researchers plan to follow up on their unprecedented discovery. “Our long-term vision is to cleanly access these lakes in order to derive if life exists,” added Rutishauser.

For now, Rutishauser said the research team is partnering with the W. Garfield Weston Foundation this spring to perform a more detailed aerogeophysical survey over Devon Ice Cap to derive more information about the lakes, including their hydrological and geological contexts.

Please follow, share and like us:
error

Roundup: Clean Climbing, Subglacial Discharges, and Nepali Youth

Denali NPS Encourages ‘Clean Climbing’

From the National Park Service: “A decade of scientific research has produced conclusive results – human waste left behind by climbers is polluting the streams and rivers that flow out of the Kahiltna Glacier. Our ultimate goal is to require 100% removal of all human waste from Denali, and we will continually strive to develop practical, working solutions to achieve this goal. We will be learning from your participation how to best to manage this next phase of ‘Clean Climbing’ on Denali.”

You can read more about how the Park Service is encouraging these practices here.

Climbers who remove all of their own waste will receive this flag from the Park Service as a reward (source: National Park Service).

 

A Forager’s Paradise for Seabirds

From Scientific Reports: “We found that tidewater glacier bays were important foraging areas for surface feeding seabirds, kittiwakes in particular. Such sites, rich in easily available food and situated in the fjord close to colonies, are used as supplementary/contingency feeding grounds by seabirds that otherwise forage outside the fjord. For kittiwakes these areas are of great significance, at least temporarily. Such an opportunity for emergency feeding close to the colony when weather conditions beyond the fjord are bad may increase the breeding success of birds and buffer the adverse consequences of climatic and oceanographic changes.”

Find out more about why these areas are so abundant here.

Researchers mapped the foraging hotspots of Kittiwake seabirds (source: Scientific Reports).

 

Nepali Youth Appeal to Trump

From The Himalayan Times: “Nepali Youth and Mountain Community Dwellers have appealed to U.S. President Donald Trump to take back his decision to pull out of the 2015 Paris Agreement on Climate Change. An appeal letter was submitted to the U.S. embassy here on Monday by Nepali youth representing people living in the foothills of the Himalayan peaks, including the tallest Mount Everest.  The letter was handed over to deputy political and economic chief of the U.S. embassy Stephanie Reed.”

Read more about why Nepalese people are so concerned over Trump’s decision here.

President Trump has withdrawn the United States from the Paris Climate Accord (source: Gage Skidmore/Flickr).
Please follow, share and like us:
error

Iceland’s fire decimates its ice: Eyjafjallajökull

A new scientific study investigates the interactions between the Icelandic volcano Eyjafjallajökull’s lava flow and the overlaying ice cap, revealing previously unknown subglacial lava-ice interactions.

Six years after  the eruption, the volcano is revisited by the author of the study, Björn Oddsson, a geophysicist with Iceland’s Department of Civil Protection and Emergency Management. He and his team present the most up-to-date chronology of the events, reverse engineer the heat transfer processes involved, and discover a phenomenon which may invalidate previous studies of “prehistoric subglacial lava fields.”

Satellite image of Iceland in 2010, during the Eyjafjallajökull eruption (Source: NASA Earth Observatory)
Satellite image of Iceland in 2010, during the Eyjafjallajökull eruption (Source: NASA Earth Observatory, annotated)

Eyjafjallajökull (‘jökull’ is Icelandic for ‘glacier’) hit headlines in April 2010, as it spewed 250 million tonnes of ash into the atmosphere. The explosive event shook the West, as it took an unprecedented toll on trans-Atlantic and European travel, disrupting the journeys of an estimated 10 million passengers. It is only known to have erupted four times in the last two millennia.

The first hint that something major was about to happen in 2010 came as a nearby fissure — Fimmvörðuhálsa — to the northeast, began spouting lava in March and April 2010. Just as Fimmvörðuhálsa quieted, a “swarm of earthquakes” rocked the Eyjafjalla range, on April 13. The next day, Eyjafjallajökull started its 39-day eruption.

Over four and a half billion cubic feet (130 million m3) of ice was liquefied and vaporized as six billion gallons of lava spewed forth from Iceland’s Eyjafjallajökull stratovolcano. Flowing at distances up to 1,640 feet (500 m) each day, the lava poured down the northern slopes of the Eyjafjalla range, nearly halving the mass of the glacier Gígjökull, as it bored a channel underneath the ice.

Oddsson and co-authors Eyjólfur Magnússon and Magnus Gudmundsson have been on the leading edge of Eyjafjallajökull research, developing a comprehensive chronology of the subglacial processes at work in 2010. To complement their timeline, they developed a model demonstrating the probable interactions and volumes involved.

Steam plumes from the caldera of Eyjafjallajökull (Source: Jon Gustafsson)
Steam plumes from the caldera of Eyjafjallajökull (Source: Jon Gustafsson)

The eruption was exceptionally well-documented and studied in real-time by the world-class volcanologists and glaciologists who populate Iceland. Oddsson’s et al. paper relied on a previously uncombined series of datasets (i.e. synthetic aperture radar (SAR), tephra sampling, seismic readings, webcam footage) to develop an holistic model to explain the subglacial formation of the 3.2 km lava field.

In April 2010, magma began to rise to the surface — the “culmination of 18 years of intermittent volcanic unrest,” according to Freysteinn Sigmundsson and colleagues. The first outflow of lava rapidly began undermining the base layers of the Eyjafjallajökull ice cap, which was then around 656 ft (200 m) thick.

Over two billion gallons of meltwater was generated. Dammed by the surrounding glacier and rock, the water pooled within the caldera (a large cauldron-shaped volcanic crater). There, it was rapidly heated, building up the subglacial pressure under Eyjafjallajökull’s ice cap over two hours — mimicking a pressure cooker.

In the early hours of April 14, a “white eruption plume” broke through the overlying ice, ultimately ascending 3.1-6.2 (5-10 km) into the atmosphere. During the first three days of the eruption, a series of vast floods — “hyperconcentrated jökulhlaup[s]” — pulsed from under Gígjökull. The first jökulhlaup completely evacuated within half an hour, at up to 1.45 million gallons (5,500 m3) per second, according to Eyjólfur Magnússon of the University of Iceland.

The outpouring of this vast volume was the first indication of an enormous transfer of energy taking place beneath the Eyjafjallajökull ice cap. Oddsson and his team determined that over 45 percent of the heat from the eruption was expended melting the ice, based on inferences of the outflowing steam, tephra, water, and other materials.

Their paper presents a culmination of several decades-worth of research, providing a substantive advance on earlier research. For instance, in 1997 Stephen Matthews’s team estimated mass fluxes in ice, water, and lava based on steam plumes, and in 2002 John Smellie made inferences on the progress of a subglacial eruption on Deception Island, Antarctica. In 2015, Duncan Woodcock and his team provided a theoretical model for the processes, but Oddsson and his colleagues have succeeded in making firmer estimates of heat flux, at a far higher temporal resolution than ever before. It is an evolution of the working group’s 2012 study of Fimmvörðuhálsa, where similar approaches were applied.

Historically, jökulhlaups have directly claimed the lives of only seven Icelanders in the past 600 years. This rate is low, due to the preparedness of local emergency services, as well as the low population density and high level of understanding within the Icelandic population. According to a study led by Magnus Gudmunsson, most fatalities occurred near Grímsvötn — Iceland’s largest subglacial lake, situated in an active volcanic caldera.

Eight-hundred people were evacuated the day before the floodwaters barrelled down the Jökulsá and Markarfljót rivers.

Around 28 percent of the lava breached the northern caldera wall, and escaped under Gígjökull. Over one-and-a-half billion cubic feet (46 million m3) of Gígjökull’s ice mass was liquefied and evaporated as the lava flowed beneath the glacier.

The degradation of Gígjökull (Source: Helgi Arnar Alfreðsson, annotated)
The degradation of Gígjökull (Source: NSIDC (left, right), Helgi Arnar Alfredsson (center), annotated)

As the lava was wasting the ice, it was being quenched by the ensuing meltwater. Four percent of the heat was lost to this water. A “lava crust” formed rapidly, insulating the rest of the lava, and preserving a high core temperature of over 1,832°F (1,000°C).  This encrusted lava continued to flow nearly two miles (3.2 km) from the summit, underneath Gígjökull, melting the overlaying ice as it descended over the following two weeks.

Oddsson’s team explored the resultant lava field, characterised by a “rough, jagged and clinkery” surface, in August 2011 and 2012. Two distinct lava morphologies had formed on the northern slopes. The longer lava field extends of 1.6 miles (2.7 km). It formed as the lava was rapidly quenched by its interaction with the ice, and ensuing meltwater. It accounts for 90 percent of the lava which poured out under Gígjökull. A second layer poured out over the top. It formed a distinctly different rock-type as it cooled, as the overlaying ice had melted, and the water had all evaporated, or flowed downriver. Accordingly, the second lava layer cooled more slowly, losing its heat to the air.

This finding is important as it unveils the processes at work in 2010, as well as having implications for studies of “prehistoric subglacial lava fields.” Dr Kate Smith of the University of Exeter commented, “It is possible that lava-ice interaction in prehistoric eruptions has been underestimated,” as the evidence was obscured by successive layers of lava from the same event, which cooled in the air, rather than interacting with ice and meltwater.

Smith noted that this new observation is a “useful contribution to the body of work on volcano-ice interaction.” The investigation has affirmed and updated earlier glaciovolcanic investigations by David Lescinsky and Jonathan Fink of Arizona State University, outline in a seminal piece in 2000. Oddsson’s et al. findings corroborate the processes Lescinsky and Fink described, though their evidence for successive layering ”partly conceal[ing]” the record is a revelation.

This latest publication by Oddsson and his team establishes a comprehensive chronology of subglacial interactions, and reliable calculations of the heat transfer processes during the 2010 Eyjafjallajökull eruption. The paper emphasises the value of field observations of volcanic eruptions, especially from ice-capped calderas. It has shone a light on previously little-considered interactions, which has consequences for palaeoenvironmental and palaeoclimatic reconstructions. Overall, it is a valuable contribution to the ever-growing database of glaciovolcanic events, and emphasises the continued need for investigations of present and historic eruptions.

Please follow, share and like us:
error

Glaciers Harbor Life Over Millennia

Gyldenlove Glacier, Greenland. Photo by NASA Goddard Space Flight Center.
Gyldenlove Glacier, Greenland. Photo by NASA Goddard Space Flight Center.

Rock samples collected at the base of glaciers in Canada, Norway, Greenland and Antarctica have helped resolve a longstanding mystery: what were the energy sources that supported life in the distant geological past, when the earth was covered with ice?

The microorganisms in subglacial habitats may have taken energy from hydrogen molecules during the harsh Neoproterozoic glaciations, 750 to 580 million years ago, according to a new study in Nature Geoscience. This hydrogen may have been the key to their survival, the authors found.

During the Neoproterozoic glaciations, ice sheets covered the world for millions of years. These ice sheets gave this period its common name, “Snowball Earth.” These environments, previously considered inhospitable to life, have been found to sustain diverse ecosystems over millennia. Subglacial environments lack carbon and light, which usually serve as energy sources for life. In well-lit environments, organisms can use light to produce organic molecules that are used by organisms higher up in the food chain. Darker environments also have organic matter, often from decaying organisms which provide energy for organisms living within them. But in subglacial environments, organic matter is quickly depleted.

“A wide diversity of microbes inhabit vast ‘wetland’ areas beneath ice sheets and many glaciers but life certainly isn’t easy for them,” Jon Telling, lead author of the paper, said in a press release. “They have to contend with cold temperatures, high pressures from overlying ice, dwindling food supplies as washed-in soils and vegetation are consumed, and constant crushing as rocks embedded in glacier beds are ground against bedrock or sediment.”

Bear glacier - Canada. Photo by Dirk Van de Velde/Flickr.
Bear glacier – Canada. Photo by Dirk Van de Velde/Flickr.

Telling and his team reproduced the conditions at the bottom of glaciers in their laboratory to better understand how life survived in these subglacial conditions. They found that some combinations of minerals and physical conditions led to hydrogen being released from rocks.  Microorganisms grab hydrogen molecules, split the bond between the two hydrogen atoms in each molecule and use the energy in the bond for the biological activity, allowing them them to live and to reproduce.

Tests were conducted with six different types of silicate rocks from glacier sites in Canada, Norway, Greenland and Antarctica and scientists regulated experimental variables like the grain size, water content and temperature. The rocks were crushed much as they would be under a glacier, and each  type was found to produce hydrogen under the proper conditions. However, calcite, the rock the researchers tested as a control, did not produce hydrogen. This result confirmed the importance of silicate rock in the survival of microorganisms.

Though the environment in the laboratory is constructed to simulate the natural conditions, there are still many differences between experiment and natural conditions. For instance, the experiment condition is rather stable while the natural conditions vary significantly. The authors pointed out that these differences and other factors are likely to lead to an underestimation of the amount of hydrogen that would be produced in natural environments. In particular, they suggest that the short duration of the experiment and the possibility of escaping gasses during the experiments would add to such an underestimation.

Sediment beneath glacier ice and bedrock at Kiattuut Sermiat Glacier, Greenland. (credit: Eddy Hill)
Sediment beneath glacier ice and bedrock at Kiattuut Sermiat Glacier, Greenland. (credit: Eddy Hill)

The study indicates that hydrogen generated through mashing rocks that can provide a mechanism in support of continued microbial metabolism. The authors note that other researchers have proposed methane as the energy source used by prehistoric microorganisms, but they show that hydrogen could have been far more abundant, and would have been available for longer periods. This hydrogen could have supported food webs in subglacial refugia, in which organic matter produced by bacteria would have provided energy for eukaryotes–organisms whose cells have the nuclei which bacterial cells lack.

Though the ancient eukaryotes were tiny, simple organisms, they are of great importance because they are the ancestors of modern multicellular organisms, from sponges and jellyfish to worms and insects to fish, reptiles birds and mammals. It is remarkable to imagine that they survived planetary glaciations that lasted millions of years by consuming organic matter produced by bacteria—and that these bacteria survived by drawing on the energy in hydrogen molecules released from rocks crushed by ice sheets.

Please follow, share and like us:
error