Deep Subsurface Research Articles

Recycling of archaeal biomass as a new strategy for extreme life in Dead Sea deep sediments

Archaea and Bacteria that inhabit the deep subsurface (known as the deep biosphere) play a prevalent role in the recycling of sedimentary organic carbon. In such environments, this process can occur over millions of years and requires microbial communities to cope with extremely limited sources of energy. Because of this scarcity, metabolic processes come at a high energetic cost, but the ways heterotrophic microbial communities develop to minimize energy expenses for a maximized yield remain unclear. Here, we report molecular biomarker evidence for the recycling of archaeal cell wall constituents in extreme evaporitic facies of Dead Sea deep sediments. Wax esters derived from the recombination of hydrolyzed products of archaeal membrane lipids were observed in gypsum and/or halite sedimentary deposits down to 243 m below the lake floor, implying the reutilization of archaeal necromass possibly by deep subsurface bacteria. By recycling the building blocks of putatively better-adapted archaea, heterotrophic bacteria may build up intracellular carbon stocks and mitigate osmotic stress in this energy-deprived environment. This mechanism illustrates a new pathway of carbon transformation in the subsurface and demonstrates how life can be maintained in extreme environments characterized by long-term isolation and minimal energetic resources.

Domestication of previously uncultivated Candidatus Desulforudis audaxviator from a deep aquifer in Siberia sheds light on its physiology and evolution.

An enigmatic uncultured member of Firmicutes, Candidatus Desulforudis audaxviator (CDA), is known by its genome retrieved from the deep gold mine in South Africa, where it formed a single-species ecosystem fuelled by hydrogen from water radiolysis. It was believed that in situ conditions CDA relied on scarce energy supply and did not divide for hundreds to thousand years. We have isolated CDA strain BYF from a 2-km-deep aquifer in Western Siberia and obtained a laboratory culture growing with a doubling time of 28.5 h. BYF uses not only H2 but also various organic electron donors for sulfate respiration. Growth required elemental iron, and ferrous iron did not substitute for it. A complex intracellular organization included gas vesicles, internal membranes, and electron-dense structures enriched in phosphorus, iron, and calcium. Genome comparison of BYF with the South African CDA revealed minimal differences mostly related to mobile elements and prophage insertions. Two genomes harbored <800 single-nucleotide polymorphisms and had nearly identical CRISPR loci. We suggest that spores with the gas vesicles may facilitate global distribution of CDA followed by colonization of suitable subsurface environments. Alternatively, a slow evolution rate in the deep subsurface could result in high genetic similarity of CDA populations at two sites spatially separated for hundreds of millions of years.

Four Draft Single-Cell Genome Sequences of Novel, Nearly Identical Kiritimatiellaeota Strains Isolated from the Continental Deep Subsurface.

The recently proposed bacterial phylum Kiritimatiellaeota represents a globally distributed monophyletic clade distinct from other members of the Planctomycetes, Verrucomicrobia, and Chlamydiae (PVC) superphylum. Here, we present four phylogenetically distinct single-cell genome sequences from within the Kiritimatiellaeota lineage sampled from deep continental subsurface aquifer fluids of the Death Valley Regional Flow System in the United States.

An Ionic Limit to Life in the Deep Subsurface.

The physical and chemical factors that can limit or prevent microbial growth in the deep subsurface are not well defined. Brines from an evaporite sequence were sampled in the Boulby Mine, United Kingdom between 800 and 1300 m depth. Ionic, hydrogen and oxygen isotopic composition were used to identify two brine sources, an aquifer situated in strata overlying the mine, and another ambiguous source distinct from the regional groundwater. The ability of the brines to support microbial replication was tested with culturing experiments using a diversity of inocula. The examined brines were found to be permissive for growth, except one. Testing this brine’s physicochemical properties showed it to have low water activity and to be chaotropic, which we attribute to the high concentration of magnesium and chloride ions. Metagenomic sequencing of the brines that supported growth showed their microbial communities to be similar to each other and comparable to those found in other hypersaline environments. These data show that solutions high in dissolved ions can shape the microbial diversity of the continental deep subsurface biosphere. Furthermore, under certain circumstances, complex brines can establish a hard limit to microbial replication in the deep biosphere, highlighting the potential for subsurface uninhabitable aqueous environments at depths far shallower than a geothermally-defined limit to life.

New ecosystems in the deep subsurface follow the flow of water driven by geological activity

Eukarya have been discovered in the deep subsurface at several locations in South Africa, but how organisms reach the subsurface remains unknown. We studied river-subsurface fissure water systems and identified Eukarya from a river that are genetically identical for 18S rDNA. To further confirm that these are identical species one metazoan species recovered from the overlying river interbred successfully with specimen recovered from an underlying mine at −1.4 km. In situ seismic simulation experiments were carried out and show seismic activity to be a major force increasing the hydraulic conductivity in faults allowing organisms to create ecosystems in the deep subsurface. As seismic activity is a non-selective force we recovered specimen of algae and Insecta that defy any obvious other explanation at a depth of −3.4 km. Our results show there is a steady flow of surface organisms to the deep subsurface where some survive and adapt and others perish. As seismic activity is also present on other planets and moons in our solar system the mechanism elucidated here may be relevant for future search and selection of landing sites in planetary exploration.

Engineered extremes: microbial interactions with steel and bentonite in a geological disposal facility

The conditions of the deep subsurface, combined by perturbations caused by geological disposal of radioactive waste create multiple extreme conditions (limited space availability, high pH, high temperature etc.) for microbial communities. Microbial activity has the potential to cause corrosion of steel and alteration of bentonite clays used in geological disposal facilities. To understand the limits on microbial growth, and the potential for microbial activity to affect the swelling behaviour of the bentonite and metal corrosion, a suite of laboratory experiments is being conducted. In situ repository conditions have been replicated in the MIND (Horizon2020) project. Preliminary results show evidence of corrosion in all experiments, an increase in the basal spacings of smectites in the zone immediately surrounding the steel and inoculated samples had evidence of calcite crystal formation, accompanied by differences in the iron phases. These experiments simulate the in situ conditions well, but the complex nature of this experimental design (high pressure and flow) reduces the practicality of varying the environmental conditions. To complement these investigations, a low-tech solution has been implemented with unpressurised, hydrated bentonite batch experiments. The simpler nature of this set-up allows for investigation of more parameters. Microcosms with artificial groundwater used in the MIND set-up are being compared to the MIND groundwater composition, modelled to represent permafrost conditions. The effect of incubation temperature is also being investigated. Combined, these experiments will help to understand the influence of microbes under the extremes of geological disposal facilities and how their behaviour may change by external parameters.

Structural and geodynamic modelling of the influence of granite bodies during lithospheric extension: Application to the Carboniferous basins of northern England

Intra-basinal highs within classic ‘block and basin’ style tectonic frameworks are underpinned by large granite bodies. This is widely believed to relate to the relative ‘rigidity’ and ‘buoyancy’ of granite in relation to accommodating basement. It has been suggested that during periods of tectonic extension, normal faulting around the peripheral regions of granite batholiths permits granite-cored blocks to isostatically resist subsidence, thus forming stable areas during periods of widespread faulting-induced subsidence. However, one-dimensional modelling indicates that relatively less dense crust is incapable of resisting subsidence in this way. Instead, when local isostasy is assumed, the occurrence of granite-cored, intra-basinal highs relates to initial isostatic compensation following granite emplacement. Differential sediment loading during extensional tectonism exaggerates this profile. An integrated two-dimensional lithospheric numerical modelling approach highlights the role of flexural rigidity in limiting the amplitude whilst increasing the wavelength of isostatic deflection. In light of these models, it is suggested that such a response leaves residual second-order stresses associated with the under-compensated buoyancy of the granite body and flexural tension. The observed basin geometries of the Carboniferous North Pennine Basin can be replicated by incorporating a density deficiency within the crust, flexural rigidity, simple shear deformation within the shallower subsurface and pure shear deformation within the deeper subsurface. In adopting this technique, the regional flexural profile in response to underlying granite bodies and large extensional faults can be reproduced and thus, to an extent, validated. It is proposed that the interaction of three factors dictate the tectonic framework within a partially granitic, brittle-ductile lithosphere and the occurrence of inter-basinal highs: 1) non-tectonic, ‘second-order’ stresses such as the flexural response of the lithosphere and residual, under-compensated buoyancy forces in relation to granite bodies; 2) extensional tectonic stress and importantly; 3) inherited basement fabric.

Bacteria and archaea on Earth and their abundance in biofilms.

Biofilms are a form of collective life with emergent properties that confer many advantages on their inhabitants, and they represent a much higher level of organization than single cells do. However, to date, no global analysis on biofilm abundance exists. We offer a critical discussion of the definition of biofilms and compile current estimates of global cell numbers in major microbial habitats, mindful of the associated uncertainty. Most bacteria and archaea on Earth (1.2 × 1030 cells) exist in the 'big five' habitats: deep oceanic subsurface (4 × 1029), upper oceanic sediment (5 × 1028), deep continental subsurface (3 × 1029), soil (3 × 1029) and oceans (1 × 1029). The remaining habitats, including groundwater, the atmosphere, the ocean surface microlayer, humans, animals and the phyllosphere, account for fewer cells by orders of magnitude. Biofilms dominate in all habitats on the surface of the Earth, except in the oceans, accounting for ~80% of bacterial and archaeal cells. In the deep subsurface, however, they cannot always be distinguished from single sessile cells; we estimate that 20-80% of cells in the subsurface exist as biofilms. Hence, overall, 40-80% of cells on Earth reside in biofilms. We conclude that biofilms drive all biogeochemical processes and represent the main way of active bacterial and archaeal life.

Fault leakage detection and characterization using pressure transient analysis

Injection of fluids in deep subsurface geological formations has created a series of challenges in recent decades. Possibility of upward fluid leakage along nearby wells and faults is one of the main issues related to these operations. It is important to ensure that such conduits, if present, can be detected, characterized and treated. Looking for pressure abnormalities in intervals above the injection zones, is one the methods used to monitor for these conduits. We propose an analytical solution to detect and characterize the vertical leakage from a fault of finite length using pressure data collected from monitoring zones. The proposed closed form analytical model would allow to not only distinguish the pressure signal of leakage from a fault of finite length from other possible leakage conduits but also to estimate the leakage rate, length of leaky section of the fault and relative position of the fault with respect to the location of monitoring well.

Characterization and discrimination of paleokarst breccias and pseudobreccias in carbonate rocks: Insight from Ordovician strata in the northern Tarim Basin, China

Ordovician carbonates in the central and southern Halahatang area of the Tarim Basin host highly productive hydrocarbon reservoirs. Previous studies suggest that the Yingshan and Yijianfang Formations (the primary producing intervals) have been extensively karstified. However, the current author has not observed significant karst features in the formations based on the detailed study of 380 m long cores from 16 wells. In the current study, true breccias are only identified in two wells in the Lianglitage Formation, including crackle and mosaic breccias as well as chaotic, clast-supported breccias. The breccias are interpreted as karst-related breccias that formed in near-surface environments during pre-Silurian subaerial exposure, and timing of karstification probably coincided with eustatic sea-level fall caused by the middle Katian glaciation. Widespread “karst features” of the Yijianfang and Yingshan Formations identified as breccias or sediment-filled cavities in many previous studies are actually only a mottled fabric (pseudobreccia) caused by selective diagenetic alteration and infiltration of bitumen in the deeper subsurface. The color difference between pseudoclasts and pseudomatrix does not reflect a mixture of clasts and cave sediments, but instead is characterized by distinct, nevertheless commonly subtle, variations in the limestone texture and whether bitumen is present. One the basis of core and thin section observations, SEM (scanning electron microscope) and XRD (X-ray diffraction) analyses, the author presents criteria to distinguish karst breccias and pseudobreccias that can be applied to other similar carbonate deposits. Discrimination between karst breccias and nodular limestones is also presented. Differentiation of karst and pseudokarst features serves not only an academic interest, but also has important applications for the exploration and development of carbonate reservoirs.

Modeling Gas Migration, Sustained Casing Pressure, and Surface Casing Vent Flow in Onshore Oil and Gas Wells

AbstractFaulty oil and gas wellbores are a primary pathway of concern for gas migration from the deep subsurface into shallow freshwater aquifers. Leaked gases migrating vertically along wellbores either collect and build a pressure at the wellhead known as sustained casing pressure (SCP) or escape into the atmosphere as surface casing vent flow (SCVF). SCP and SCVF are valuable indicators of integrity loss that provide insight into the potential for groundwater contamination through gas migration. Previous models of SCP and SCVF have focused on offshore wells and have not considered the relationship between SCP/SCVF and gas migration away from onshore wells. We present the first modeling framework for SCP and SCVF that is applicable to onshore oil and gas wells constructed with outermost annuli that are hydraulically connected or “open” to the surrounding formation. Our results show that SCP behavior is unique in onshore wells with open annuli, because steady state SCP is not achieved in an open annulus unless gas escapes the wellbore via gas migration (Darcy Flow), a wellhead leak, or a controlled bleed‐off test. We show that appropriately modeling gas leakage along the wellbore and SCP/SCVF helps to constrain methane leakage fluxes from faulty wells and could be integrated with subsurface flow and transport models of stray gas contamination. By relating gas fluxes to SCP/SCVF, our model can provide information used to support regulatory actions informed by SCP/SCVF, which are easy to measure and monitor.

沖縄諸島島嶼部の深部地盤S波速度構造の推定－数値モデル構築のために

沖縄諸島島嶼部の深部地盤S波速度構造の推定－数値モデル構築のために

Viruses control dominant bacteria colonizing the terrestrial deep biosphere after hydraulic fracturing.

The deep terrestrial biosphere harbours a substantial fraction of Earth's biomass and remains understudied compared with other ecosystems. Deep biosphere life primarily consists of bacteria and archaea, yet knowledge of their co-occurring viruses is poor. Here, we temporally catalogued viral diversity from five deep terrestrial subsurface locations (hydraulically fractured wells), examined virus-host interaction dynamics and experimentally assessed metabolites from cell lysis to better understand viral roles in this ecosystem. We uncovered high viral diversity, rivalling that of peatland soil ecosystems, despite low host diversity. Many viral operational taxonomic units were predicted to infect Halanaerobium, the dominant microorganism in these ecosystems. Examination of clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins (CRISPR-Cas) spacers elucidated lineage-specific virus-host dynamics suggesting active in situ viral predation of Halanaerobium. These dynamics indicate repeated viral encounters and changing viral host range across temporally and geographically distinct shale formations. Laboratory experiments showed that prophage-induced Halanaerobium lysis releases intracellular metabolites that can sustain key fermentative metabolisms, supporting the persistence of microorganisms in this ecosystem. Together, these findings suggest that diverse and active viral populations play critical roles in driving strain-level microbial community development and resource turnover within this deep terrestrial subsurface ecosystem.

Exploration of deep terrestrial subsurface microbiome in Late Cretaceous Deccan traps and underlying Archean basement, India

Scientific deep drilling at Koyna, western India provides a unique opportunity to explore microbial life within deep biosphere hosted by ~65 Myr old Deccan basalt and Archaean granitic basement. Characteristic low organic carbon content, mafic/felsic nature but distinct trend in sulfate and nitrate concentrations demarcates the basaltic and granitic zones as distinct ecological habitats. Quantitative PCR indicates a depth independent distribution of microorganisms predominated by bacteria. Abundance of dsrB and mcrA genes are relatively higher (at least one order of magnitude) in basalt compared to granite. Bacterial communities are dominated by Alpha-, Beta-, Gammaproteobacteria, Actinobacteria and Firmicutes, whereas Euryarchaeota is the major archaeal group. Strong correlation among the abundance of autotrophic and heterotrophic taxa is noted. Bacteria known for nitrite, sulfur and hydrogen oxidation represent the autotrophs. Fermentative, nitrate/sulfate reducing and methane metabolising microorganisms represent the heterotrophs. Lack of shared operational taxonomic units and distinct clustering of major taxa indicate possible community isolation. Shotgun metagenomics corroborate that chemolithoautotrophic assimilation of carbon coupled with fermentation and anaerobic respiration drive this deep biosphere. This first report on the geomicrobiology of the subsurface of Deccan traps provides an unprecedented opportunity to understand microbial composition and function in the terrestrial, igneous rock-hosted, deep biosphere.

Characteristics and formation mechanism of seafloor domes on the north‐eastern continental slope of the South China Sea

Multibeam echo‐sounding and seismic data were obtained during three geophysical surveys by Guangzhou Marine Geological Survey (GMGS) on the north‐eastern slope of the South China Sea (SCS). Nineteen seafloor domes and numerous elongated pockmarks were distinguished in the study area. The seafloor domes vary on number of summits, shape, and spatial interrelation, based on which they were classified into four types which are single‐summit, double‐summits, elongated, and connected. Bottom simulating reflectors and blanking zone underneath were observed in the seismic profiles, indicating the potential existence of gas hydrate and free gas. Multiple faults and diapirs exist beneath the seafloor domes and pockmarks, which were inferred to provide efficient pathways for fluid migrating from deep subsurface. The seafloor domes exhibits high backscatter feature, which is potentially associated with the seep‐related gas hydrate and authigenic carbonate in the shallow sediment. It is speculated that fault and diapir activity, fault sliding caused by region extension and the interaction between neighbour domes control and affect the activity and formation of the domes. However, further investigations, including geological sampling and seafloor observation, are still needed to confirm whether they are mud volcanoes.

Introduction of an Experimental Terrestrial Forecasting/Monitoring System at Regional to Continental Scales Based on the Terrestrial Systems Modeling Platform (v1.1.0)

Operational weather and flood forecasting has been performed successfully for decades and is of great socioeconomic importance. Up to now, forecast products focus on atmospheric variables, such as precipitation, air temperature and, in hydrology, on river discharge. Considering the full terrestrial system from groundwater across the land surface into the atmosphere, a number of important hydrologic variables are missing especially with regard to the shallow and deeper subsurface (e.g., groundwater), which are gaining considerable attention in the context of global change. In this study, we propose a terrestrial monitoring/forecasting system using the Terrestrial Systems Modeling Platform (TSMP) that predicts all essential states and fluxes of the terrestrial hydrologic and energy cycles from groundwater into the atmosphere. Closure of the terrestrial cycles provides a physically consistent picture of the terrestrial system in TSMP. TSMP has been implemented over a regional domain over North Rhine-Westphalia and a continental domain over Europe in a real-time forecast/monitoring workflow. Applying a real-time forecasting/monitoring workflow over both domains, experimental forecasts are being produced with different lead times since the beginning of 2016. Real-time forecast/monitoring products encompass all compartments of the terrestrial system including additional hydrologic variables, such as plant available soil water, groundwater table depth, and groundwater recharge and storage.

Recent developments and future directions of deep biosphere research

<p indent=0mm>The deep biosphere consists of microorganisms that thrive in continental and oceanic subsurface, and are independent of photosynthesis. Subsurface microorganisms live in rock fractures and subsurface fluids, and extract nutrients and energy from water-rock reactions. Globally, subsurface microbial biomass is comparable to total surface biomass, but its distribution is extremely heterogeneous, and metabolic rate is very slow, depending on specific geological conditions. Overall, with increased depth, microbial biomass, diversity, and activity decrease, likely because of more extreme environmental conditions in the subsurface (increased temperature and pressure, but decreased nutrients and pore space). Surface and shallow subsurface processes are driven by photosynthesis, and surface-derived H₂O, O₂, ¹⁴C, and ³⁷Cl diffuse downward. Deep subsurface processes are driven by geogas (H₂, CH₄, CO₂, and He). Temperature is the most important environmental condition that ultimately limits the depth of the biosphere, but this limit can be influenced by other conditions, such as nutrient levels and pressure. Limited data have shown that deep subsurface environment is dominated by bacteria (>50%) but archaea, eukaryotes and viruses are all present. Proteobacteria and Firmicutes are two dominant bacterial phyla and their relative proportions change with depth. In shallow and young sediments/rocks with relatively low temperature, Proteobacteria are dominant, but in deeper and older rocks with higher temperatures, Firmicutes become more important. Archaea are also widespread in the subsurface, and often consist of Euryarchaeota (dominantly Methanomicrobia) and Thaumarchaeota. Unlike sediments and sedimentary rocks at shallow depths where surface-derived organic matter is present, microbes in the deep subsurface usually depend on H₂ as a major source of energy. H₂ can be derived from several pathways including radiolysis of water, serpentinization of ultramafic and mafic rocks, and water splitting by highly oxidizing radicals. In addition, methane oxidation, Fe/S oxidation, and sulfur-driven nitrate reduction may provide additional sources of energy for fueling subsurface microbes. Subsurface microorganisms have adapted to extreme environments, and are usually anaerobic, chemolithotrophic, thermophilic, halophilic piezophilic, oligotrophic, radiation and desiccation resistant, however, the specific survival limits have remained largely elusive. Among these physiological traits, thermophilic and halophilic microbes appear to be predominant in the subsurface. To survive in low-energy environments, subsurface microbes have evolved specialized metabolic pathways and have developed less permeable cell membranes to minimize ion loss. Despite these evolutionary traits, unique subsurface microbes, e.g., those with unique physiologies that are distinctly different from surface microbes, are rare. <italic>Ca. </italic>D. audaxviator, originally found in South Africa deep mines and later discovered in other continents, is the only one that appears to be endemic to subsurface environment. Therefore, subsurface microorganisms may be unique in the functions, but not necessarily in taxonomy. Due to the difficulty of obtaining subsurface samples and high cost, deep biosphere research is still in early stage. A number of important questions remain elusive such as: (1) The origin, survival, and evolution rates of subsurface microorganisms; (2) geological conditions that ultimately limit microbial survival in the subsurface; (3) biogeographic distribution of subsurface microorganisms; (4) the microbial role in the global cycles of carbon and other elements; (5) alternative energy sources; (6) co-evolution of the geosphere and biosphere. To answer these questions, <italic>in-situ</italic> imaging and isotopic tracers are some of the important tools to analyze low-biomass samples. International collaboration is needed to coordinate sample collection and processing, to jointly analyze samples, and to share the data and samples. Among all these, education is the key to ensure that a stable and highly interdisciplinary team of professionals are motivated to advance the subsurface microbiology investigation to the next level.

Rare Biosphere Archaea Assimilate Acetate in Precambrian Terrestrial Subsurface at 2.2 km Depth

The deep biosphere contains a large portion of the total microbial communities on Earth, but little is known about the carbon sources that support deep life. In this study, we used Stable Isotope Probing (SIP) and high throughput amplicon sequencing to identify the acetate assimilating microbial communities at 2260 m depth in the bedrock of Outokumpu, Finland. The long-term and short-term effects of acetate on the microbial communities were assessed by DNA-targeted SIP and RNA targeted cell activation. The microbial communities reacted within hours to the amended acetate. Archaeal taxa representing the rare biosphere at 2260 m depth were identified and linked to the cycling of acetate, and were shown to have an impact on the functions and activity of the microbial communities in general through small key carbon compounds. The major archaeal lineages identified to assimilate acetate and metabolites derived from the labelled acetate were Methanosarcina spp., Methanococcus spp., Methanolobus spp., and unclassified Methanosarcinaceae. These archaea have previously been detected in the Outokumpu deep subsurface as minor groups. Nevertheless, their involvement in the assimilation of acetate and secretion of metabolites derived from acetate indicated an important role in the supporting of the whole community in the deep subsurface, where carbon sources are limited.

Imaging and monitoring of the shallow subsurface using spatially windowed surface-wave analysis with a single permanent seismic source

Development of shallow subsurface monitoring systems is important for monitoring the ground stability of shallow formation, and also for conventional deep seismic monitoring because with current techniques, temporal changes in shallow seismic velocities can influence monitoring results for the deep subsurface. We have developed an effective shallow seismic imaging and monitoring system with high spatiotemporal resolution and accuracy using a continuous and controlled source system, the accurately controlled routinely operated signal system (ACROSS). The method applies surface-wave analysis to characterize and monitor the shallow subsurface from the spatiotemporal variation of phase velocities. Because the number of available ACROSS units is usually limited, estimating a shallow subsurface with high spatial resolution is a challenging issue in ACROSS-based monitoring. To overcome this problem, we introduced a 2D spatial window into multichannel analysis of surface waves. We analyzed continuous ACROSS data acquired during seven different data periods from 2014 to 2016 at the Aquistore [Formula: see text] storage site in Canada. As a result, we clearly estimated spatial variations of phase velocities using only a single ACROSS unit. The numerical experiments of our method suggested that the spatial variations could be associated with shallow geologic boundaries in the study area. We identified clear seasonal variations of phase velocities in winter, possibly related to ground freezing in shallow sediments, and we showed the high temporal stability of our monitoring approach in warmer seasons. These results indicated that our approach would have the potential to identify spatiotemporal change in shallow subsurface associated with natural phenomena or fluid leakage.

Draft Genome Sequence of Rhizobium sp. Strain T2.30D-1.1, Isolated from 538.5 Meters Deep on the Subsurface of the Iberian Pyrite Belt

Rhizobium sp. strain T2.30D-1.1 was isolated from the deep subsurface of the Iberian Pyrite Belt. We report its draft genome, consisting of 60 contigs with a chromosome of ≈4.6 Mb and a plasmid of 179 kb. The annotation revealed 4,526 coding DNA sequences, 45 tRNA genes, and 1 rRNA operon.