A jellyfish pictured in an Antarctic ice shelf borehole.
Life finds a way. That way may be uncomfortable, brimming with struggle, and demand an unsightly appendage or two, but as Jeff Goldblum reminds us, "Life will not be contained, life breaks free, it expands to new territories, and it crashes through barriers painfully, maybe even dangerously, but, uh, there it is."
To crash through those barriers, however, creatures must find the requirements for life waiting on the other side: namely, liquid water, a source of energy, and biogenic elements such as carbon and nitrogen. While terrestrial life has found some environments too hostile to call home, it's also evolved mind-boggling adaptations that allow it to access those three essentials in some bizarre places.
For example, the denizens of hydrothermal vents—such as the yeti crabs, scaly-foot gastropods, and Pompeii worms—dwell too deep in the ocean for sunlight to reach. Because their food chains can't rely on photosynthesis, they're supported by microbes that utilize a process called chemosynthesis, which converts chemicals from the vents into sugars and, in turn, useable energy.
Similarly, the Atacama Desert is a place so dry and barren that scientists compared it to the rusty dunes of Mars. Yet, even here, life has found a way in the form of microbes who wait patiently for those fleeting spits of rainfall to replicate.
And a new study, published in Frontiers in Marine Science, has proven Goldblum correct, uh, yes, once again. The study details the discovery of unusual creatures in one of the most unsympathetic environments on Earth's most inhospitable continent.
A cold dark place to call home
The Antarctic sessile creatures photographed on their home boulder.
Credit: Frontiers in Marine Science
Researchers made the discovery while drilling boreholes on the Filchner-Ronne Ice Shelf. Antarctica's ice shelves are giant, permanent floating ice sheets connected to the continent's coastlines, with the Filchner-Ronne shelf being one of the largest. Using a hot-water drill system, they bore through roughly 900 meters of the ice looking for sediment samples. Instead, they discovered a boulder. Two hundred sixty kilometers away from the ice front, the rock was nestled in a world of complete darkness at -2.2°C. And on it, they found sessile organisms.
"This discovery is one of those fortunate accidents that pushes ideas in a different direction and shows us that Antarctic marine life is incredibly special and amazingly adapted to a frozen world," Dr Huw Griffiths, the study's lead author and a biogeographer of the British Antarctic Survey, said in a press release.
Sessile creatures are defined by their inability to move freely. They live their lives anchored to a substrate—in this case, the aforementioned boulder. Common sessile animals found in coastal tide pools include mussels, barnacles, and sea anemones, yet none of these were present beneath the Antarctic shelf. Instead, the researchers discovered a stalked sponge, roughly a dozen non-stalked sponges, and 22 unidentifiable stalked organisms.
Previous boreholes had revealed creatures living in these murky waters, but they had always been free-moving predators and scavengers such as jellyfish and krill. It's not too surprising to find such animals under the ice shelves as their mobility allows them to seek out food that may drift beneath.
But sessile organisms depend on their food to be delivered to them. That's why they are so bountiful in tide pools; tides and currents are the DoorDash of the ocean world. It's also why the researchers found the sponge's Antarctic lodgings so astounding. Because they live 1,500 kilometers upstream from the nearest source of photosynthesis, it's unknown how a food supply reaches these sponges or whether they generate nutrients from some other means, such as glacial melt or carnivorous noshing.
"Our discovery raises so many more questions than it answers, such as how did they get there? What are they eating? How long have they been there? How common are these boulders covered in life? Are these the same species as we see outside the ice shelf or are they new species? And what would happen to these communities if the ice shelf collapsed?" Griffiths added.
To answer those questions, researchers will need to revisit the sponges to collect samples and study them in more depth. We'll also need to explore further the vast reaches of the Antarctic continental shelf. According to the release, counting the previous boreholes, scientists have only studied an area roughly the size of a tennis court to date.
Life will not be contained
As science discovers life in more and more unusual places, it's also considering more and more that life has not been contained to our pale blue dot. For example, the recent discovery of microbial life in the Atacama Desert has reignited hope that evidence of past life will be found on Mars. NASA's Perseverance Rover recently land on Mars to begin analyzing soil samples from the Jezero Crater to test that hypothesis.
Looking to the future, NASA's Dragonfly rotorcraft aims to explore the Saturn moon of Titan. The icy moon has a makeup similar to early Earth's, so the vehicle will study the moon's atmosphere and surface for signs of chemical evidence for life. And the ice-covered surface of Europa could hold twice as much water as Earth and a bevy of hydrothermal activity that could harbor life within our solar system.
Here life is, uh, and there it may be.
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In recent years, our team at Iowa State University has found a way to make pigs an even closer stand-in for humans. We have successfully transferred components of the human immune system into pigs that lack a functional immune system. This breakthrough has the potential to accelerate medical research in many areas, including virus and vaccine research, as well as cancer and stem cell therapeutics.
Existing biomedical models
Severe Combined Immunodeficiency, or SCID, is a genetic condition that causes impaired development of the immune system. People can develop SCID, as dramatized in the 1976 movie “The Boy in the Plastic Bubble." Other animals can develop SCID, too, including mice.
Researchers in the 1980s recognized that SCID mice could be implanted with human immune cells for further study. Such mice are called “humanized" mice and have been optimized over the past 30 years to study many questions relevant to human health.
Mice are the most commonly used animal in biomedical research, but results from mice often do not translate well to human responses, thanks to differences in metabolism, size and divergent cell functions compared with people.
Nonhuman primates are also used for medical research and are certainly closer stand-ins for humans. But using them for this purpose raises numerous ethical considerations. With these concerns in mind, the National Institutes of Health retired most of its chimpanzees from biomedical research in 2013.
Alternative animal models are in demand.
Swine are a viable option for medical research because of their similarities to humans. And with their widespread commercial use, pigs are met with fewer ethical dilemmas than primates. Upwards of 100 million hogs are slaughtered each year for food in the U.S.
Humanizing pigs
In 2012, groups at Iowa State University and Kansas State University, including Jack Dekkers, an expert in animal breeding and genetics, and Raymond Rowland, a specialist in animal diseases, serendipitously discovered a naturally occurring genetic mutation in pigs that caused SCID. We wondered if we could develop these pigs to create a new biomedical model.
Our group has worked for nearly a decade developing and optimizing SCID pigs for applications in biomedical research. In 2018, we achieved a twofold milestone when working with animal physiologist Jason Ross and his lab. Together we developed a more immunocompromised pig than the original SCID pig – and successfully humanized it, by transferring cultured human immune stem cells into the livers of developing piglets.
During early fetal development, immune cells develop within the liver, providing an opportunity to introduce human cells. We inject human immune stem cells into fetal pig livers using ultrasound imaging as a guide. As the pig fetus develops, the injected human immune stem cells begin to differentiate – or change into other kinds of cells – and spread through the pig's body. Once SCID piglets are born, we can detect human immune cells in their blood, liver, spleen and thymus gland. This humanization is what makes them so valuable for testing new medical treatments.
We have found that human ovarian tumors survive and grow in SCID pigs, giving us an opportunity to study ovarian cancer in a new way. Similarly, because human skin survives on SCID pigs, scientists may be able to develop new treatments for skin burns. Other research possibilities are numerous.
The ultraclean SCID pig biocontainment facility in Ames, Iowa. Adeline Boettcher, CC BY-SA
Pigs in a bubble
Since our pigs lack essential components of their immune system, they are extremely susceptible to infection and require special housing to help reduce exposure to pathogens.
SCID pigs are raised in bubble biocontainment facilities. Positive pressure rooms, which maintain a higher air pressure than the surrounding environment to keep pathogens out, are coupled with highly filtered air and water. All personnel are required to wear full personal protective equipment. We typically have anywhere from two to 15 SCID pigs and breeding animals at a given time. (Our breeding animals do not have SCID, but they are genetic carriers of the mutation, so their offspring may have SCID.)
As with any animal research, ethical considerations are always front and center. All our protocols are approved by Iowa State University's Institutional Animal Care and Use Committee and are in accordance with The National Institutes of Health's Guide for the Care and Use of Laboratory Animals.
Every day, twice a day, our pigs are checked by expert caretakers who monitor their health status and provide engagement. We have veterinarians on call. If any pigs fall ill, and drug or antibiotic intervention does not improve their condition, the animals are humanely euthanized.
Our goal is to continue optimizing our humanized SCID pigs so they can be more readily available for stem cell therapy testing, as well as research in other areas, including cancer. We hope the development of the SCID pig model will pave the way for advancements in therapeutic testing, with the long-term goal of improving human patient outcomes.
Adeline Boettcher earned her research-based Ph.D. working on the SCID project in 2019.
Christopher Tuggle, Professor of Animal Science, Iowa State University and Adeline Boettcher, Technical Writer II, Iowa State University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Volcano erupting lava, volcanic sky active rock night Ecuador landscape
How can modern technology help warn us of impending volcanic eruptions?
One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.
The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.
For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.
Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.
"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."
Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.
Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.
In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.
The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.
"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."
