evolution

Hot Off the Seep: Novel Cyanobacteria with Hefty Implications for Carbon Cycling

Posted on by Anna Bennett

Cyanobacteria, microscopic photosynthetic bacteria, have been quietly shaping our planet for billions of years. Responsible for producing the oxygen we breathe, these tiny organisms play a critical role in the global carbon cycle and are now stepping into the spotlight for another reason: their potential to both understand and potentially combat climate change. 

Image of Volcano Island (Baia di Levante) in Italy where the cyanobacterial strains were isolated. Image contains rock formations and a body of water in the foreground with more rock formations in the background.
Baia di Levente. Marine, volcanic seeps in Italy where UTEX 3221 and UTEX 3222 were discovered. Image credit: Adobe Stock.

Recently, researchers discovered two new strains of cyanobacteria, UTEX 3221 and UTEX 3222, thriving in a marine volcanic seep off the coast of Italy. While cyanobacteria are virtually everywhere there is water and light—from calm freshwater ponds to extreme environments like Yellowstone’s hot springs—this particular habitat is remarkable for its naturally high CO₂ levels and acidic conditions. For these newly identified strains, a geochemical setting like marine volcanic seeps have likely driven the evolution of unique traits that could make them valuable for carbon sequestration and industrial applications. 

How can something so small make such a big impact? In this blog, we explore what makes these newly discovered cyanobacteria special and how this research could help address some of the world’s most pressing challenges. 

A Dense Discovery from the Depths of Baia di Levante

The Baia di Levante, nestled near Italy’s Vulcano Island, is a place where geology and biology collide. This shallow marine region is dotted with volcanic seeps that continuously release CO₂ into the water, creating an environment rich in CO₂ while maintaining an acidic (low) pH. Unlike deeper oceanic vents, where sunlight cannot penetrate, Baia di Levante’s shallow waters provide the key ingredient for photosynthesis: light. For most organisms, these conditions would pose significant challenges. But for photosynthetic microorganisms, these particular volcanic seeps offer an abundance of resources: CO₂, sunlight, and water.  

In the hunt for novel photosynthetic species, researchers sampled from seeps in Baia di Levante and identified two novel cyanobacteria strains, UTEX 3221 and UTEX 3222. Among these, UTEX 3222 quickly emerged as a standout, showcasing a combination of traits that make it uniquely promising for research and industrial applications. 

For starters, UTEX 3222 boasts a doubling time of just 2.35 hours—making it one of the fastest-growing cyanobacteria studied to date. In laboratory cultures, it produces over 31 grams of dry biomass per liter, nearly double the yield of some of the current model strains used in biotechnology. It thrives under diverse conditions, tolerating high salinity, varying pH levels, and elevated temperatures, all while maintaining robust growth. 

There are a handful of common lab strains that researchers use to study cyanobacterial photosynthesis in situ. In comparison, UTEX 3222 is much larger than the common laboratory strain, Synechococcus elongatus. Furthermore, UTEX 3222’s cells are noticeably larger and form denser colonies. The strain also contains significantly more carbon, stored in visible white granules within its cells. Finally, researchers found that the strain was considerably heavier’ than S. elongatus: when placed in a test tube, UTEX 3222 rapidly sunk to the bottom, a deviation from other strains. Thus, UTEX 3222 was affectionately given the name “Chonkus” for its particularly dense phenotype.   

Balancing Carbon Capture and Ecosystem Impact

Cyanobacteria have long been recognized for their versatility in industrial applications as they readily convert sunlight and carbon dioxide into biomass. Thus, these photosynthetic bacteria are often used as workhorses for synthesizing materials in a more sustainable way.  Their use spans a wide range of industries, from producing biofuels and bioplastics to synthesizing valuable compounds like vitamins, pigments, and pharmaceuticals. In recent years, they’ve also gained attention for their potential in carbon capture technologies, where their rapid growth and high photosynthetic efficiency can play a pivotal role in reducing atmospheric CO₂ levels. 

In industrial processes, biomass harvesting is often one of the most costly and resource-intensive steps. Traditional methods rely on chemical flocculants or complex filtration systems to separate cells from their growth medium. Chonkus, however, naturally settles to the bottom of a container within hours, forming a dense pellet. This trait could drastically reduce the time, energy, and cost required to collect biomass, making it an attractive candidate for large-scale bioproduction.  

Beyond industry, Chonkus has profound implications for carbon sequestration. In natural ecosystems, cyanobacteria and other photosynthetic organisms play a critical role in the carbon cycle, capturing CO₂ from the atmosphere and converting it into biomass. However, much of this carbon is recycled back into the environment when these organisms die and decompose near an ocean or lake surface. The strain’s rapid settling behavior could change this dynamic. By sinking to deeper ocean layers, its biomass has the potential to transport carbon to regions where it can remain stored for centuries.  

But carbon that sinks doesn’t simply vanish—it interacts with the ocean floor, an environment actively cycling other elements like nitrogen, phosphorus, and sulfur. Introducing large amounts of cyanobacterial biomass to these deep ecosystems could shift nutrient balances and alter microbial communities. While this presents exciting possibilities for carbon sequestration, it also highlights the need for careful study of long-term impacts on ocean nutrient cycling, geochemistry, and biodiversity. 

This behavior is closely tied to the ocean’s biological pump, a natural process that moves organic carbon from the surface to the deep sea. Enhancing this process with organisms like Chonkus could offer a scalable tool for mitigating climate change by increasing the amount of carbon stored in deep ocean layers. However, as we explore these possibilities, it’s essential to understand how such interventions might affect nutrient cycling and biodiversity on the ocean floor. Balancing the promise of carbon sequestration with its ecological implications will be critical for leveraging photosynthetic bacteria in future applications.

Read more about this research in Science.

Ice Age Secrets: The Discovery of a Juvenile Sabretooth Cat Mummy 

Posted on by Shannon Sindermann

In the permafrost of Siberia, a remarkable discovery has been made—a mummified juvenile sabretooth cat, Homotherium latidens, frozen in time for over 35,000 years. This discovery, made along the Badyarikha River in the Indigirka River Basin of Yakutia, Russia, offers an exciting glimpse into a species that has no modern analog (a living equivalent of something extinct) (1). For paleontologists and evolutionary biologists, it provides an unprecedented look at an ancient predator that roamed the Earth during the Ice Age. So, how is this cub mummy truly fascinating scientists?  

A Rare Find  

Homotherium Sabretooth mummy
The frozen mummy of Homotherium latidens: (A) external appearance; (B) skeleton, CT-scan, dorsal view (1).

The permafrost of Siberia is a treasure trove of Ice Age fossils, but the discovery of a mummified Homotherium cub stands out for its rarity and significance. While bones can tell us a lot about the history of an extinct species, mummies—where the animal’s soft tissues, such as fur, skin and sometimes internal organs, are preserved—offer far more detailed information. ‘Mummies’ refer to animals (or humans) that have been preserved with their soft tissues intact, often through natural or intentional processes like drying or embalming. This preservation allows scientists to gain insights into the organism’s diet, health, development and adaptations—details that bones alone can’t reveal! 

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Shocking Revelation about Starfish Anatomy: Just a Head

Posted on by AnnaKay Kruger
Two starfish on the beach
Recent research reveals that starfish anatomy is even stranger than previously thought

Most animals in the world are what biologists refer to as “bilateral”—their left and right sides mirror one another. It is also typically easy to tell which part of most animals is the top and which is the bottom. The anatomical arrangements of certain other animals, however, are slightly more confounding, for instance in the case of echinoderms, which include sea urchins, sand dollars and starfish. These animals are “pentaradial”, with five identical sections of the body radiating from a central axis. The question of how these creatures evolved into such a state has been a puzzle pondered by many a biologist, with little progress made until recently. In a new study published in Nature, scientists closely examining the genetic composition of starfish point to some key evidence that suggests a starfish is mostly just a head.

Starfish are a deuterostome, belonging to the superphylum Deuterostomia. Most deuterostomes are bilateral, leading scientists to believe that, despite their peculiar body plan, starfish evolved from a bilateral ancestor. This is supported by the fact that starfish larvae actually start out bilateral, and eventually transform into the characteristic star shape. But where the head of the starfish is, or whether it even has one, has proved difficult for scientists to parse out, especially since their outward structure offers no real clues.

There have been a number of theories posited, such as the duplication hypothesis—where each of the five sections of a starfish could be considered “bilateral”, placing the head at the center—and the stacking hypothesis, which asserts that the body is stacked atop the head. In a bilateral body plan, anterior genes broadly code for the front, or the head-region, and posterior genes are primarily responsible for the tail. The torso, or “trunk”, is the result of complex interplay between both anterior and posterior, as well as other types of genes. Researchers in this new study looked at the expression of these genes throughout the body plan as a possible source of clarity as to which part of the starfish is its head and which parts comprise the body.

To this end, researchers used advanced molecular and genetic sequencing techniques including RNA tomography and in situ hybridization. RNA tomography allowed them to create a three-dimensional map of gene expression throughout the limbs of the sea star Patiria miniate. In situ hybridization is a fluorescent staining technique that offered them a means by which to examine where exactly anterior or posterior genes are expressed in the sea star’s tissue, providing a clearer picture of genetic body patterning.

Remarkably, scientists found that anterior or head-coding genes were expressed in the starfish’s skin, including head-like regions appearing in the center, or midline, of each arm, while tail-coding genes were only seen at the outer edges of the arms. Perhaps even more remarkable was the lack of genetic patterning accounting for a trunk or torso, leading scientists to the conclusion that starfish are, for the most part, just heads.

Whether this holds true for other echinoderms remains to be proven, and further investigations into starfish anatomy may seek to pinpoint where in the timeline the trunk was lost. Overall, research like this helps scientists understand how life came to look the way it does. Oddly shaped creatures like the humble starfish can offer insight into the strange evolutionary processes that result in such rich biodiversity across the animal kingdom.

Works cited:

  1. ‘A disembodied head walking about the sea floor on its lips’: Scientists finally work out what a starfish is | Live Science
  2. Molecular evidence of anteroposterior patterning in adult echinoderms | Nature
  3. Starfish Are Heads–Just Heads – Scientific American
  4. Study reveals location of starfish’s head | Stanford News

Uncovering the Origins of the Commensal House Mouse

Posted on by Sara Klink
Figure of house mouse. Copyright George Shuklin.
📷: George Shuklin

When I encounter my cat fixated on specific locations in my kitchen, her behavior shows me that she has heard some mice in those areas. In fact, mice have been attributed as a reason that cats became companions to humans. Mice start gathering and reproducing so cats followed the food source and hunted the rodents, thus endearing themselves to humans, who were storing food for their own use. However, new evidence described in Scientific Reports has shown that mice have been associated with humans even before grain storage was widespread. In fact, by making our dwellings comfortable, we also created an inviting place for mice to live.

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Which Came First: The Virus or the Host?

Posted on by Ken Doyle

They existed 3.5 billion years before humans evolved on Earth. They’re neither dead nor alive. Their genetic material is embedded in our own DNA, constituting close to 10% of the human genome. They can attack most forms of life on our planet, from bacteria to plants to animals. And yet, if it wasn’t for them, humans might never have existed.

3D structure of a coronavirus, viral evolution
A depiction of the shape of coronavirus as well as the cross-sectional view. The image shows the major elements including glycoproteins, viral envelope and helical RNA. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

No, that’s not the blurb for a new Hollywood blockbuster, although recent developments have proven, once again, that truth is decidedly more bizarre than fiction. Now that “coronavirus” has become a household word, the level of interest in all things virus-related is growing at an unprecedented rate. At the time of writing, coronavirus and COVID-19 topics dominated search traffic on Google, as well as trends on social media. A recent FAQ on this blog addresses many of the questions we hear on these topics.

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