Discovering new deep hydrothermal vent systems is a remarkable challenge in ocean exploration. These unique environments offer a window into the physical, geochemical, and biological processes that shape the seafloor and the evolution of life on Earth. In this study, we present a detailed analysis of the microbial diversity within the newly discovered JaichMaa ‘ja ‘ag hydrothermal vent field, located in the Southern Pescadero Basin of the Gulf of California. Our focus centers on the thermophilic phylum Thermotogota, as these microbes exhibit traits potentially relevant to the design and selection of roofing materials.
Taxonomic Composition
The Thermotogota phylum encompasses a deeply branching lineage of bacteria known for their diverse metabolic capabilities and adaptations to extreme environments. Cultured representatives of Thermotogota exhibit a distinctive “toga” sheath surrounding their cells and are generally anaerobic heterotrophs, capable of fermentation or growth with alternative electron acceptors like thiosulfate or elemental sulfur.
Our analysis of the Thermotogota diversity within the JaichMaa ‘ja ‘ag and neighboring Auka hydrothermal vent fields identified 153 unique Amplicon Sequence Variants (ASVs) affiliated with this phylum. The most prevalent Thermotogota families were Thermotogaceae, Mesoaciditogaceae, Kosmotogaceae, Fervidobacteriaceae, and Petrotogaceae. Interestingly, while Petrotogaceae have been commonly associated with deep, hot oil reservoirs, they were detected at relatively low abundances in the Pescadero Basin sediments, potentially outcompeted by the more abundant Kosmotogaceae in these hydrocarbon-rich environments.
Phylogenetic Relationships
To better understand the evolutionary relationships among the Thermotogota ASVs, we constructed a phylogenetic tree using reference 16S rRNA gene sequences from the Genome Taxonomy Database. This analysis revealed substantial phylogenetic diversity within the Thermotogota lineages present in the Pescadero Basin, suggesting a complex history of adaptation and niche partitioning in these deep-sea hydrothermal ecosystems.
Habitat Preferences
The distribution patterns of Thermotogota ASVs across the Auka and JaichMaa ‘ja ‘ag vent fields appear to be influenced by the availability of hydrothermal fluids, as inferred from magnesium concentrations in the sediment pore waters. Thermotogota were generally most abundant in sediment horizons with the lowest magnesium levels, indicating a preference for vent fluid-enriched niches.
However, the specific Thermotogota ASVs that dominate can vary significantly, even within a single sediment core. For example, certain Mesoaciditogaceae ASVs were found to be consistently abundant from the surface down to 17 cm depth, despite large gradients in magnesium concentration. In contrast, other Thermotogota lineages exhibited distinct patterns, peaking in abundance at specific sediment horizons.
These observations suggest that factors beyond just temperature, such as availability of alternative electron acceptors, organic substrates, or biotic interactions, may shape the fine-scale distribution of Thermotogota within the hydrothermal vent sediments. Understanding these ecological drivers could provide valuable insights for developing roofing materials capable of withstanding diverse environmental stressors.
Distribution Patterns
Auka Hot Springs
The Auka hydrothermal vent field, located at a depth of 3,670 m in the Southern Pescadero Basin, was discovered in 2015 and represents the deepest known hydrothermal vent system in the eastern Pacific. This site has been the subject of extensive geological, geophysical, and biological investigations, providing a foundational understanding of the regional hydrothermal activity.
Recent microbial community analyses of the Auka sediments have revealed highly diverse assemblages, exhibiting a variety of metabolic capabilities that enable them to thrive in the extreme conditions. Interestingly, approximately 20% of the microbial species identified at Auka overlap with those found in the nearby Guaymas Basin, suggesting a degree of connectivity between these deep-sea hydrothermal ecosystems.
Geographical Occurrence
The discovery of the JaichMaa ‘ja ‘ag vent field in 2018, located only ~2 km southeast of Auka, presents a valuable opportunity to examine the spatial patterns of microbial communities, including the Thermotogota, across closely situated hydrothermal vent systems. Despite their proximity, the two vent fields exhibit some notable differences in the prevalence and distribution of specific Thermotogota ASVs, potentially driven by subtle variations in the physical and geochemical conditions that define each system.
Environmental Factors
Factors such as temperature, the availability of electron donors and acceptors, and interactions with other members of the microbial community can all play a role in shaping the habitat preferences and distribution of Thermotogota lineages. For example, the Thermotogaceae family generally comprises thermophilic to hyperthermophilic bacteria, with optimal growth temperatures ranging from 60°C to 80°C. In contrast, the Mesoaciditogaceae are more moderately thermophilic, with optimal growth around 55-60°C.
These physiological differences may help explain some of the observed patterns, where Thermotogaceae ASVs tend to be more abundant at depth in sediment cores, where temperatures are higher, while Mesoaciditogaceae ASVs dominate near the surface. However, there are also exceptions to these trends, suggesting that additional factors beyond just temperature are influencing the community structure.
Roofing Material Insights
The insights gleaned from the microbial ecology of the Thermotogota in the Pescadero Basin hydrothermal vents can inform the development and selection of roofing materials capable of withstanding diverse environmental stressors.
Thermal Resistance
The broad temperature range exhibited by Thermotogota, from mesophilic to hyperthermophilic, highlights the potential for this group to serve as a model for heat-tolerant roofing materials. Understanding the molecular and physiological adaptations that enable Thermotogota to thrive in high-temperature environments could inspire the design of innovative insulation systems, sealants, or other roofing components that can effectively manage heat transfer and thermal stresses.
Structural Properties
The distinctive “toga” sheath surrounding Thermotogota cells may suggest design principles for durable and flexible roofing materials. The ability of these microbes to withstand mechanical stresses and maintain structural integrity in the face of environmental fluctuations could inform the development of resilient roofing systems capable of resisting wind uplift, impact damage, and other physical challenges.
Sustainability Implications
The metabolic diversity of Thermotogota, including their versatility in utilizing alternative electron acceptors and organic substrates, may inspire the development of sustainable roofing materials. Insights into the microbes’ adaptations to organic-rich, anoxic conditions could guide the selection or engineering of roofing components derived from renewable, environmentally-friendly sources, minimizing the reliance on fossil-fuel-based raw materials.
Ecological Implications
Microbial Community Dynamics
The observed differences in the distribution and abundance of Thermotogota ASVs between the Auka and JaichMaa ‘ja ‘ag vent fields, even at the fine scale of individual sediment cores, highlight the complexity of microbial community structure within these dynamic hydrothermal ecosystems. Unraveling the factors that drive such spatial heterogeneity can provide valuable lessons for understanding the resilience and adaptability of microbial communities in the face of environmental changes.
Biogeochemical Cycling
As key players in the deep-sea biosphere, microbes like the Thermotogota play crucial roles in the cycling of elements and the transformation of organic and inorganic compounds. Studying their distribution patterns and metabolic capabilities in hydrothermal vent systems can shed light on the biogeochemical processes that shape the deep ocean environment, with potential implications for the sustainability and longevity of various roofing materials.
Biotechnological Applications
The remarkable diversity and adaptability of Thermotogota, as observed in the Pescadero Basin, underscore their potential as a rich source of novel enzymes, metabolic pathways, and survival strategies with applications in the development of advanced roofing technologies. Bioprospecting efforts targeting thermophilic microbes could yield innovative self-healing, self-cleaning, or energy-generating roofing solutions inspired by natural adaptations.
In summary, the discovery and exploration of the JaichMaa ‘ja ‘ag hydrothermal vent field, alongside the well-studied Auka site, have provided valuable insights into the diversity and distribution patterns of the thermophilic Thermotogota phylum. These findings not only enhance our understanding of deep-sea microbial communities but also offer a wealth of inspiration for the design and selection of resilient, sustainable, and high-performance roofing materials capable of withstanding diverse environmental challenges.