Worms: How Do These Marine Worms Survive Extreme Antarctic Cold…

Antarctic marine worms, known as polychaetes, rely on a symbiotic relationship with specialized bacteria to survive the extreme cold of their environment. This remarkable adaptation sheds light on the complex interplay between marine organisms and their microbial partners, offering new insights into life under extreme conditions.

Unraveling the Mystery about these marine worms

Polychaetes, close relatives of earthworms, are ubiquitous on the ocean floor, yet their survival in the frigid waters of Antarctica has long puzzled scientists. Unlike some Antarctic species such as icefish, which produce their own antifreeze proteins, most Antarctic organisms do not generate these protective proteins.

“Other Antarctic species, like icefish, make their own antifreeze proteins, but most Antarctic organisms do not produce these proteins,” explains Cinzia Corinaldesi, a marine ecologist at Marche Polytechnic University in Ancona, Italy.

The Role of Beneficial Bacteria in these marine worms

The secret to the marine worms’ (polychaetes’) survival lies in their association with beneficial bacteria. Corinaldesi and her team discovered that these bacteria produce proteins that help the worms withstand the freezing temperatures. This groundbreaking finding, published on June 21 in Science Advances, highlights the crucial role microbes play in the survival of their hosts.

Amy Apprill, a microbial ecologist at Woods Hole Oceanographic Institution, underscores the significance of this discovery about these marine worms. “Our knowledge of host-microbe interactions in the ocean is still incredibly limited,” she says, emphasizing the importance of such research.

Field and Laboratory Research

To uncover this symbiotic relationship, Corinaldesi’s colleagues embarked on an expedition to three coastal areas of Antarctica in the Ross Sea. They collected ocean sediment containing three common marine worm species: two that scavenge on dead organisms and one predator. The water temperature at these sites was around –1° Celsius.

Back in Italy, Emanuela Buschi, now a researcher at Anton Dohrn Zoological Station in Fano, analyzed the DNA of the worms to identify the resident microbes. The analysis revealed the presence of Meiothermus silvanus and two types of Anoxybacillus bacteria, which were absent in the surrounding sediment and in DNA samples from other related worms.

---

More for you:

> Mysterious ‘Hole’ on Mars Sparks Enthusiasm: A Potential Refuge for Future Human Expeditions…
> Thwaites Glacier; Unveiling the New Significant Threat Beneath…!
> Asthma Linked to Cell Overcrowding in Airways: A New Understanding Emerges…

---

Cold-tolerance Proteins in these marine worms

The bacteria living inside the polychaetes produce proteins that enhance the worms’ cold tolerance. Two enzymatic proteins, in particular, generate glycerol and proline, compounds known to protect against extreme cold by lowering the freezing point of internal fluids.

“These proteins are thought to protect against extreme cold due to their ability to reduce the freezing point of internal liquids,” Corinaldesi explains.

Interestingly, Meiothermus bacteria, although currently missing from the Antarctic ocean floor, have been found in frozen sediment beneath the nearby Ross Ice Shelf. This historical presence suggests a long-term relationship between the polychaetes (marine worms) and these bacteria.

Corinaldesi and her colleagues believe that the bacteria are passed down from parent worms to their offspring, maintaining this beneficial partnership across generations.

Future Research Directions

To confirm that young marine worms inherit these helpful microbes from their parents, further research is needed to analyze the microbiome of polychaetes at various life stages. There is also the possibility that newborn worms acquire the bacteria through interactions with other worms.

The bacteria benefit from this relationship by gaining a secure habitat within the worms in exchange for producing protective proteins. “The bacteria receive a safe home in exchange for making protective proteins,” Corinaldesi says.

Exploring Antarctic Microbiomes

Corinaldesi continues to investigate the intricate relationships between Antarctic marine worms and their microbial partners, aiming to understand how these associations evolved. “Studying Antarctic microbiomes will allow us to understand many secrets of life adaptation to extreme conditions,” she notes.

This research not only unravels the mystery of how polychaetes survive in Antarctic waters but also underscores the vital role of microbial symbiosis in extreme environments. As scientists delve deeper into these interactions, they may uncover new strategies for life adaptation that could have broader implications for understanding the resilience of life on Earth and potentially other planets.