A new study by researchers at Portland State University and the University of Wisconsin finds that a rich diversity of microorganisms live in interdependent communities in high-temperature geothermal environments in the deep sea. The study, which was published in the journal microbiome, was led by Anna-Louise Reysenbach, a professor of biology at PSU. Emily St. John, who earned a master’s degree in microbial ecology from PSU, also contributed significantly to the study, along with researchers from the University of Wisconsin.
When 350-400℃ fluid exiting the earth’s crust through deep-sea hydrothermal vents mixes with seawater, it creates large porous rocks often referred to as “chimneys” or hydrothermal reservoirs. . These chimneys are colonized by microbes that thrive in high-temperature environments. For decades, Reysenbach has collected vents from deep-sea hydrothermal vents in the world’s oceans, and his lab uses farming techniques and genetic fingerprinting to study the microbial diversity of communities associated with these rocks.
In this new study, Reysenbach and the team were able to take advantage of advances in molecular biology techniques to sequence the complete genomes of microbes in these communities to learn more about their diversity and interconnected ecosystems.
The team constructed genomes of 3,635 bacteria and archaea from 40 different rock communities. The amount of diversity was staggering and greatly expands what is known about how many different types of bacteria and archaea exist. The researchers discovered at least 500 new genera (the taxonomic level of organization above species) and have evidence for two new phyla (five levels above species). “Phyla is very high up in taxonomic rank, so that’s great,” says Reysenbach.
The team also found evidence of microbial diversity hotspots. Samples from the deep-sea Brothers volcano located near New Zealand, for example, were specially enriched with different types of microorganisms, many endemic to the volcano.
“That biodiversity was so huge, off the charts,” says Reysenbach. “There was so much new diversity in one volcano that we hadn’t seen anywhere else before.” This finding may suggest that the greater complexity of a volcano’s subsurface rocks makes them more likely to host diverse microbial species compared to deep-sea hydrothermal vents.
In addition to finding a staggering amount of microorganism biodiversity in these high-temperature ecosystems, the genomic data from this study also showed that many of these organisms depend on each other for survival. By analyzing the genomes, the researchers discovered that some microorganisms cannot metabolize all the nutrients they need to survive, so they rely on nutrients created by other species in a process known as “metabolic transfer.”
“By looking at these genomes, we really got a better understanding of what many of these microorganisms do and how they interact,” says Reysenbach. “They are communal; they share food with each other.”
This study has inspired a new phase of research for Reysenbach: gaining a deep understanding of the interactions between these deep-sea microorganisms. “For me, the most exciting part is that I really want to be able to grow these things in the lab,” says Reysenbach. “I want to be able to see [a microorganism] under a microscope and understand if he needs someone else to live with.
Zhichao Zhou et al, Global patterns of diversity and metabolism of microbial communities in deep-sea hydrothermal vent deposits, microbiome (2022). DOI: 10.1186/s40168-022-01424-7
Provided by Portland State University
Citation: Study Finds Immense Diversity and Interdependence in High-Temperature Microorganism Communities in Deep Seas (January 24, 2023) Accessed January 24, 2023 at https://phys.org/news/2023-01-immense- diversity-interdependence-high-temperature. html
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