Great Artesian Basin Of Australia Research Articles

The internal structure of spring mounds of Nefzaoua oasis in Tunisia: Formation of an original geomorphic structure

AbstractSpring mounds are specific geomorphological landforms in arid or semi‐arid environments associated with playas and artesian springs. Spring mounds are found worldwide, especially in the great Artesian Basin of Australia and in North American and Egyptian deserts. They result from an exceptional succession of climatic, geomorphological and hydrogeological conditions, with processes that follow each other in a specific order. In Tunisia, in the arid zone, ca. 126 spring mounds have been identified in Nefzaoua province alone, especially in the oasis east of Chott el Jerid. They have a conical shape that ranges from 200 to more than 2000 m in diameter and 3–30 m tall, and their centre is hollowed out by an artesian spring of fresh water. Palm groves (Phoenix dactylifera) spread out at the foot of each mound. The springs have dried up because of the proliferation of borehole wells. Because of the low electric conductivity (EC) of the sediments (<1 mS cm−1) at their base, spring mounds have been excavated and used as a soil amendment to expand new palm plantations. This excavation allows for analysis of their internal structure, which has never been observed well. In the present study, fine analysis of sediment layers in four sections of two representative mounds showed that vegetation had trapped sediment at their base. Fine strata of variable texture alternating with variable calcium carbonate, gypsum or organic carbon contents suggest a clear limnic origin. Many redoximorphic features, sometimes associated with the presence of old roots, suggest variation in the water level in the centre of the mound. The mounds are capped by a thick layer of indurated gypsum, which helps them resist hydric and aeolian erosion. The origin of the sediment components is discussed.

Time capsules of biodiversity: Future research directions for groundwater-dependent ecosystems of the Great Artesian Basin

The Great Artesian Basin of Australia represents one of the largest and deepest basins of freshwater on Earth. Thousands of springs fed by the Basin are scattered across Australia’s arid zone, often representing the sole sources of freshwater for thousands of kilometers. As “islands” in the desert, the springs support endemic fauna and flora that have undergone millions of years of evolution in almost total isolation. Here, we review the current body of knowledge surrounding Great Artesian Basin springs and their significance from ecological, evolutionary, and cultural perspectives using South Australian spring wetlands as a case study. We begin by identifying the status of these springs as critical sources of groundwater, the unique biodiversity they support, and their cultural significance to the Arabana people as Traditional Custodians of the land. We then summarize known threats to the springs and their biota, both exogenous and endogenous, and the potential impacts of such processes. Finally, considering the status of these at-risk habitats as time capsules of biodiversity, we discuss lessons that can be learnt from current conservation and management practices in South Australia. We propose key recommendations for improved biodiversity assessment and monitoring of Great Artesian Basin springs nationwide, including 1) enhanced legal protections for spring biota; 2) increased taxonomic funding and capacity; 3) improved biodiversity monitoring methods, and 4) opportunities for reciprocal knowledge-sharing with Aboriginal peoples when conducting biodiversity research.

Residence times of groundwater along a flow path in the Great Artesian Basin determined by 81Kr, 36Cl and 4He: Implications for palaeo hydrogeology

Understanding the age distribution of groundwater can provide information on both the recharge history as well as the geochemical evolution of groundwater flow systems. Of the few candidates available that can be used to date old groundwater, 81Kr shows the most promise because its input function is constant through time and there are less sources and sinks to complicate the dating procedure in comparison to traditional tracers such as 36Cl and 4He. In this paper we use 81Kr in a large groundwater basin to obtain a better understanding of the residence time distribution of an unconfined-confined aquifer system. A suite of environmental tracers along a groundwater flow path in the south–west Great Artesian Basin of Australia have been sampled. All age tracers (85Kr, 39Ar 14C, 81Kr, 36Cl and 4He) display a consistent increase in groundwater age with distance from the recharge area indicating the presence of a connected flow path. Assuming that 81Kr is the most accurate dating technique the 36Cl/Cl systematics was unravelled to reveal information on recharge mechanism and chloride concentration at the time of recharge. Current-day recharge occurs via ephemeral river recharge beneath the Finke River, while diffuse recharge is minor in the young groundwaters. Towards the end of the transect the influence of ephemeral recharge is less while diffuse recharge and the initial chloride concentration at recharge were higher.

Response of spring wetlands to restored aquifer pressure in the Great Artesian Basin, Australia

• Water extraction has reduced aquifer pressure in the Great Artesian Basin, Australia. • Flows to springs have declined but endemic species have survived. • Open drains have been replaced by polyethylene pipe restoring aquifer pressure. • Spring wetlands have expanded and management implications are discussed. • Decline in aquifer pressure, loss of springs and then recovery provides lessons for the world. The decline in aquifer water tables resulting from groundwater extraction and the impacts on spring ecosystems is a recurring management issue throughout the world. This study from the Great Artesian Basin in Australia demonstrates how water extraction through uncapped (open) bores since the late nineteenth century has reduced aquifer pressure, dewatering many natural springs. Flow rates to one spring complex at Pelican Creek also declined, but an extraordinary array of endemic species have persisted. At Pelican Creek an extremely rare endemic fish, the red-finned blue-eye ( Scaturiginichthys vermeilipinnis ) is threatened with extinction from predation by an exotic fish gambusia ( Gambusia holbrooki ). A government-funded program to cap flowing bores and to replace the distribution of groundwater through open drains with polyethylene pipe has resulted in the partial restoration of aquifer pressure coinciding with the expansion of spring wetlands. The restoration of springs enhances habitat for spring-dependent endemic species, but also makes the removal of gambusia more difficult and the opportunities for dispersal into the few remaining springs free of gambusia more likely. The documentation of the decline in aquifer pressure and loss of springs, followed by pressure recovery with aquifer management, and local management of springs provides lessons for the parallel circumstances throughout the globe.

Hydrogeological implications of fault behaviour from in situ pressure measurements of the Horrane Fault in the Surat Basin (Great Artesian Basin, Australia)

In order to assess the impact of faulting on the production and compartmentalisation of a coal seam gas (CSG) reservoir, seismic reflection surveys and subsequent drilling were undertaken to locate and then intersect the Horrane Fault in the eastern Surat Basin, in the Great Artesian Basin of Australia. The investigation of the Horrane Fault in the area of Cecil Plains on the Darling Downs identified faulting at depths of 50–600 m within the Walloon Coal Measures. Pressure data collected during the drilling show differential pressures on each side of the fault. The differential is interpreted to show depletion on the western side of the fault due to the CSG production field located west of the fault. On the eastern side of the fault, the pressures were near hydrostatic, and thus the fault is acting as a lateral seal. Regional modelling currently simulates faults as having permeability based upon the fraction of the units off-set across the fault. This would lead to exaggerated predictions of impact not supported by the data from this study. Conceptual models of the Surat Basin are currently based upon the premise that connectivity by direct linkages due to the faults enhances groundwater-level changes due to water extraction and that the behaviour of the faults is poorly understood. This study represents the first detailed evaluation of fault behaviour in the eastern Surat Basin and can be used to update current conceptual models and inform regional groundwater impact assessments.

Groundwater Dependent Ecosystems in Arid Zones Can Use Ancient Subterranean Carbon as an Energy Source in the Local Food Web

AbstractGroundwater dependent ecosystems (GDEs) are defined by their reliance on subterranean water resources, but GDE food webs may also depend on it as an energy source. Mazumder et al. (2019, https://doi.org/10.1029/2018JG004925), show a clear dependency of a local GDE food web on very old, potentially geological, carbon sourced from palaeo‐groundwater discharge in the arid Great Artesian Basin in Australia. These findings support the emerging paradigm that ancient groundwater carbon is an important component of inland water carbon cycling and contemporary ecosystem functioning. Future work is needed to determine what proportion of total GDE energy needs are derived from groundwater carbon across a range of geological and hydroclimatic settings.

In Search of Lost Springs: A Protocol for Locating Active and Inactive Springs.

Groundwater springs are significant landscape features for humans and the biota that occupies their habitat. Many springs become inactive where groundwater exploitation by humans has lowered the water table or artesian pressure. In order to assess this impact, it is important to identify and locate active, and with more difficulty, inactive springs. Using a variety of archival, environmental and field-based data, this study presents a protocol for the determination of the location and status of springs across the Great Artesian Basin of Australia. This protocol underpins a database of springs, which is not only important for the assessment of spring ecosystems, but also contributes to understand groundwater extraction impacts and hydrogeological processes. The database indicates that 30.0% of discharge (artesian) springs in the Great Artesian Basin are entirely inactive and another 11.8% are partially inactive. For the outcrop (gravity) springs of the Basin, only 1.9% are entirely inactive and 7.4% partially inactive, and for the outcrop springs in the Tertiary sandstone overlying the Basin 30.9% are inactive and 18.2% are partially inactive.

Draft Genome Sequence of Anoxybacillus Strain BCO1, Isolated from a Thermophilic Microbial Mat Colonizing the Outflow of a Bore Well of the Great Artesian Basin of Australia.

Anoxybacillus strain BCO1, isolated from a thermophilic (50°C) microbial mat colonizing an outflow of a Great Artesian bore well of Australia, possessed a genome of ~2.8 Mb, with a G+C content of 41.7 mol%, and encoded 3,205 genes.

Chemical weathering processes in the Great Artesian Basin: Evidence from lithium and silicon isotopes

Variations in lithium and silicon isotope ratios in groundwaters of the Great Artesian Basin in Australia, and the causes of these variations, have been explored. The chemistries of Li and Si in groundwater are influenced by the dissolution of primary phases, the formation of secondary minerals, and the reaction of solid phases with dissolved constituents, while isotopic variations are generated by uptake into clays, which preferentially incorporate the light isotopes. The lithium isotopic composition (expressed as δLi7) of the groundwaters ranges from +9 to +16‰, and clearly reflects changes in aquifer conditions. Reaction-transport modelling indicates that changes in Li concentrations are principally controlled by the ratio of the weathering rate of primary minerals to the precipitation rate of secondary minerals, whereas δLi7 is affected by the extent of isotope fractionation during secondary mineral formation (which is dependent on mineralogy). The patterns of groundwater Si concentrations and δSi30 values versus flow distance suggest that Si is at steady state in the aquifer. The δSi30 value of most of the groundwater samples is close to −1‰, which is significantly lower than the δSi30 value of the reservoir rocks (∼0‰). Since precipitation of clays preferentially removes the light Si isotopes from solution, the most plausible explanation for these low groundwater δSi30 values is addition of Si by dissolution of isotopically light secondary minerals. These data, together with model calculations, show that Li isotopes are extremely sensitive to changes in the chemical and physical conditions in the aquifer, whereas Si is not. Importantly, the model suggests that even in large aquifers with long fluid residence times, where steady-state would be expected to be reached, the concentrations and isotopic fractionation of trace elements are not controlled by Li adsorption. The model developed here provides a basis for using Li isotopes measured in groundwaters and surface waters to constrain weathering processes.

Australian sedimentary opal-A and its associated minerals: Implications for natural silica sphere formation

The vast majority of precious opal on the world market comes from opal fields in the Great Artesian Basin of Australia pointing to very special prerequisites for amorphous silica to consolidate in a way that leads to the famous play-of-color. We analyzed 20 opal-A samples from the Andamooka (South Australia) and Yowah (Queensland) precious opal fields, using petrographic microscopy, XRPD, SEM, and EPMA to identify and characterize opaline silica, the mineral assemblage, and the host rock. Opal-A consists of submicrometer-sized silica spheres with an average diameter of 140-320 nm. The average diameter of monodisperse spheres is 140-290 nm with a relative standard deviation (RSD) of <6%. Polydisperse spheres show an average diameter of 160-320 nm with a RSD larger than 10%. This dichotomy in size is reflected by the Na/K ratio at both localities. Monodisperse spheres show values below 1.2 while polydisperse ones show a ratio larger than 3.0, whereas other contaminations with higher valence show no correlations at all. We therefore suggest that the jump in Na/K signals a fundamental change of pH and salinity of the silica-bearing mineralizing fluids. Judging from the pH stability of the host rock minerals with predominating alunite, kaolinite, illite and gypsum, and omnipresent barite and anatase we conclude that the dominant late-stage mineralization leading to precious opal happened at acidic pH. Our findings indicate that the host rocks and associated minerals are the key to unravel the complex history of opal-forming solutions. A quantitative opal classification based on sphere diameters and their variability, decoupled from gemological properties, is to be established.

Geochemistry and Travertine Dating Provide New Insights into the Hydrogeology of the Great Artesian Basin, South Australia

While of great national and societal significance, and importance in its own right, the Great Artesian Basin of Australia is an iconic example of a continental scale artesian groundwater system. New geochemical, hydrological, and neo-tectonic data suggests that existing models that involve recharge in eastern Australia, relatively simple flowpaths and discharge in springs in the western margin require modification. New geochemical data indicate a small volume flux of deeply derived (endogenic) fluids mixing into the aquifer system at a continental scale. Neo- tectonic data indicates active tectonism today that provides a fluid pathway through faults for the deeply sourced endogenic fluids to discharge in GAB travertine depositing springs.

Extreme Acidic Environments Associated with Carbonate Mound Springs in the Great Artesian Basin, South Australia

A reduction in the piezometric surface of the western part of the Great Artesian Basin in Australia has led to reductions in flow from the iconic travertine mound springs. This has led to oxidation of sub-aqueous sulfidic soils in the discharge zone and in some cases extreme soil acidification (pH<1). Net acidities are extremely high (>20,000mol H+/tonne) and oxidation has induced intense weathering of the soils and adjacent carbonate mounds. Concomitant high evaporation rates have led to the development of thick layers of rare hydroxysulfate efflorescent minerals, which are highly soluble stores of acidity and metals. Preliminary Fe isotope data show significant fractionation associated with the oxidation and transport of Fe in soil profiles.

Groundwater recharge areas of the Continental Intercalaire aquifer-hydrogeochemical and environmental isotopes: Southern Tunisia and Algeria

The Continental Intercalaire (C.I.) aquifer is one of the two aquifer members that constitutes the North-Western Sahara Aquifer System (NWSAS) shared by Algeria, Tunisia and Libya extending over an area of more than one million km2. The Continental Intercalaire (C.I.) aquifer is one of the largest confined-to semi confined aquifers in the world, comparable in scale to the Nubian Sandstone Aquifer System (NSAS) shared by Egypt, Sudan, Libya, and Chad, as well as the Great Artesian Basin of Australia, and covers some 600,000 km2 with a potential reservoir thickness of between 120 and 1000 m. The aquifer is mostly unconfined, unlike the eastern part. Its depth increases from north to south and from west to east. It has a shape of a depression that disappears further south where it becomes confined. TDS increases southward along the recognized flow path (0.7 ≤ TDS ≤ 8.7 g/l). Major elements increase with the increase of TDS. The radiocarbon activities of the groundwater are very low, varying between 0.27 and 70.3% modern carbon. The confined part of the reservoir shows depleted stable isotopes data and low 14C content, reflecting the absence of modern water at the discharge zone. The combined evidence shows that the recharge coincides with cooler, humid periods during the Late Pleistocene, which existed across the whole of Saharan Africa.

High-temperature deep-subsurface microbial communities as a possible equivalent of ancient ecosystems

Microbiological, molecular biological, and radioisotopic studies suggest that active and complex microbial communities exist in the deep layers of the subsurface biosphere. This review discusses only one group of such communities, i.e., those developing at high (above 60°C temperatures). Oil wells, subsurface water reservoirs (e.g., the Great Artesian Basin in Australia), deep mines (in South Africa), and high-temperature horizons below the seafloor in the areas of underwater volcanic activity contain the best-studied high-temperature subsurface ecosystems. These microbial communities differ considerably from one another in biodiversity, initial energy substrate, and major microbiological processes. However, before they can be considered as equivalents of the Earth’s primordial ecosystems, it is necessary to demonstrate that they are energetically independent of the modern biosphere.

Valuing reductions in water extractions from groundwater basins with benefit transfer: The Great Artesian Basin in Australia

The management of groundwater to generate net community benefits is challenging because of the complexity of impacts that can be involved, the varying interests of different stakeholder groups, time lags between changes in extraction rates and aquifer levels, and the level of technical and scientific uncertainty. In an economic framework, decisions about conserving groundwater reserves by limiting extraction rates should be made by comparing the benefits of conservation activities with the associated costs. However, limited information about benefits and costs makes it difficult to apply a benefit‐cost framework to issues of groundwater management. This can be addressed to some extent by sourcing nonmarket values from other studies in a benefit transfer process. In this paper, benefit transfer techniques are applied to an evaluation case study about limiting extractions from the Great Artesian Basin in Australia. The results demonstrate some of the issues with the benefit transfer approach and confirm that the publicly funded bore capping program in Australia has been delivering net benefits to the community.

Caloramator mitchellensis sp. nov., a thermoanaerobe isolated from the geothermal waters of the Great Artesian Basin of Australia, and emended description of the genus Caloramator

A strictly thermophilic anaerobe, designated strain VF08(T), was isolated from a water sample collected from a Great Artesian Basin bore (registered bore number 22981) situated at Mitchell, QLD, Australia. Cells of isolate VF08(T) were slightly curved, non-sporulating rods (1.5-3.5 x 0.4-0.8 μm), which stained Gram-negative but possessed a Gram-positive cell-wall ultrastructure. The strain grew optimally in tryptone-yeast extract-glucose (TYEG) medium at 55 °C (temperature growth range between 37 and 60 °C) and a pH of 7 (pH growth range, 6.0-9.0). Yeast extract or tryptone was required for growth on glucose, fructose, xylose, maltose, sucrose, raffinose, cellobiose, ribose, pyruvate, tryptone, peptone, Casamino acids, amyl media and serine, but could also support growth as the sole carbon source. End products from glucose fermentation were acetate, ethanol, CO₂ and H₂. The strain reduced vanadium(V), but not iron(III), manganese(IV), elemental sulfur, sulfate, thiosulfate, sulfite, nitrate or nitrite in the presence of 0.2 % yeast extract, peptone, tryptone, glucose, sucrose and Casamino acids, but an increase in the growth rate or cell yield was not observed. Growth was inhibited by chloramphenicol, streptomycin, tetracycline, penicillin, ampicillin and ≥ 2 % NaCl (w/v). The G+C content of the DNA was 38.4 ± 0.8 mol% as determined by the thermal denaturation (T(m)) method. 16S rRNA gene sequence analysis revealed that isolate VF08(T) was a member of the genus Caloramator with Caloramator australicus and Caloramator fervidus (formerly Clostridium fervidus) being the closest relatives with similarity values of 85.0 and 86.1 %, respectively, when helix 6 nucleotides were included in the analysis, and 95.2 % and 94 %, respectively, when these nucleotides were masked from the analysis. Further analysis revealed that strain VF08(T) formed an individual cluster (cluster II) within the genus Caloramator and could be distinguished from other species within the genus Caloramator (clusters I, III and IV) on the basis of signature nucleotides and differences in phenotypic traits. These data suggest that strain VF08(T) is a novel species of the genus Caloramator, for which the name Caloramator mitchellensis sp. nov. is proposed. The type strain is VF08(T) (=JCM 15828(T)=KCTC 5735(T)). An emended description of the genus Caloramator is also provided.

Ranking spring wetlands in the Great Artesian Basin of Australia using endemicity and isolation of plant species

Floristic survey data from spring wetlands in the Great Artesian Basin of Australia were assessed to generate a ranked list of significant flora values. A system was designed to score endemic species and remote populations of plants, using an extensive herbarium database to set the spring flora in context. The sum of these indices for individual wetland complexes yielded a ranked score. The high priority wetland complexes (scoring five or greater) adequately represent their floristic composition, capture all endemic plant species and 76% of the flora. Although data are limited, many of the high value spring wetlands have endemic fauna of which the snails have been most thoroughly surveyed. The procedure provides direction for an efficient conservation program that if implemented should provide security against a range of threatening processes.

Microvirga subterranea gen. nov., sp. nov., a moderate thermophile from a deep subsurface Australian thermal aquifer.

A strictly aerobic bacterium, strain Fail4T, was isolated from free-flowing geothermal waters of a bore (bore register no. 3768) tapping the Great Artesian Basin of Australia. The non-sporulating, Gram-negative cells of strain Fail4T produced light-pink colonies, were rod-shaped (1 x 1.5-4 microm) and were motile by a single polar flagellum. Strain Fail4T grew optimally at 41 degrees C at a pH of 7.0 and had an absolute requirement for yeast extract. The strain grew on casein hydrolysate, tryptone, gelatin, xylose and acetate in a medium supplemented with 0.06 or 0.006% yeast extract. Weak acid production was detected from glucose and arabinose. Catalase was produced. Nitrite was produced from nitrate. Strain Fail4T was sensitive to antibiotics that inhibit growth of bacteria. The G + C content was 63.5 +/- 0.5 mol%. Strain Fail4T was a member of the class 'Alphaproteobacteria', phylum Proteobacteria, placed almost equidistantly between Methylobacterium species, Chelatococcus asaccharovorans and Bosea thiooxidans (similarity value of 93%) as its nearest phylogenetic relatives. Phylogenetic and phenotypic evidence suggest that strain Fail4T (=ATCC BAA-295T = DSM 14364T) should be placed as the type strain of a species in a newly created genus, for which the name Microvirga subterranea gen. nov., sp. nov. is proposed.

Thermaerobacter subterraneus sp. nov., a novel aerobic bacterium from the Great Artesian Basin of Australia, and emendation of the genus Thermaerobacter.

A strictly aerobic, thermophilic, gram-positive, spore-producing, rod-shaped bacterium (2.0-10.0 x 0.3 microm), designated isolate C21T, was isolated from a sample collected from an open drain run-off channel of a bore in the Great Artesian Basin of Australia (New Lorne Bore, registered number 17263). Isolate C21T grew optimally at 70 degrees C (temperature range for growth was 55-80 degrees C) and pH 8.5 (pH range for growth was 6.0-10.5), with a generation time of 90 min. The isolate was strictly heterotrophic and grew on yeast extract and/or tryptone as carbon and energy sources. An increase in growth was not observed with carbohydrates (sucrose, cellobiose, glucose, dextrin, amylopectin, chitin, carboxymethylcellulose, xylan, inositol, arabinose, mannose, fructose, gelatin, starch, amylose, galactose, dextrose, xylose, maltose, L-sorbose or raffinose), organic acids (lactic acid, pyruvic acid or benzoic acid) or Casamino acids as sole carbon sources or in the presence of yeast extract and/or tryptone. The G+C content of the chromosomal DNA, as measured by the thermal denaturation method, was 71 mol%. Phylogenetic analysis of the 16S rRNA gene of isolate C21T placed it as a member of the phylum Firmicutes, with Thermaerobacter marianensis as the closest relative (similarity value of 98%). However, isolate C21T and T. marianensis differed in a number of key physiological and phenotypic properties and also had a DNA-DNA hybridization value of less than 5%. Based on this evidence, it is proposed that strain C21T be designated Thermaerobacter subterraneus sp. nov. (type strain C21T = ATCC BAA-137T = DSM 13965T).

Bacillus subterraneus sp. nov., an iron- and manganese-reducing bacterium from a deep subsurface Australian thermal aquifer.

A facultatively anaerobic bacterium, designated strain COOI3B(T) (= ATCC BAA 136T = DSM 13966T), was isolated from the waters emitted by a bore well tapping the deep subterranean thermal waters of the Great Artesian Basin of Australia. The cells were straight to slightly curved rods (0.5-0.8 x 2-25 microm) that occurred singly and rarely in pairs or in chains. Strain COOI3B(T) was motile by peritrichous flagella. It stained gram-negative, but electron micrographs showed a gram-positive-type cell wall. Spores were never observed and cells were heat-sensitive. Yeast extract at 0.02% (w/v) was required for growth and could also be used as a sole carbon and energy source at concentrations higher than 0.1% (w/v). The strain utilized amorphous iron(III), manganese(IV), nitrate, nitrite and fumarate as electron acceptors in the presence of yeast extract, glucose, sucrose, fructose, maltose, xylose, starch, glycerol, ethanol or lactate. Electron acceptors were not obligately required and growth was better in the presence of nitrate than in its absence. Acid was not produced from growth on carbohydrates. Tryptophan deaminase, H2S, arginine dihydrolase, lysine decarboxylase, beta-galactosidase, arabinosidase, glucuronidase, glucosaminidase, nitroanilidase, xylosidase and ornithine decarboxylase were not produced. Starch and gelatin, but not casein, were hydrolysed. Aesculin and catalase, but not oxidase and urease, were produced. Strain COOI3B(T) grew optimally at temperatures between 37 and 40 degrees C (the temperature growth range was 25-45 degrees C) and at pH 7.0-9.0 (the pH growth range was 6.0 to 9.5) with 5% (w/v) NaCl (the NaCl concentration growth range was 0.9%, w/v). The DNA base composition was 43 +/- 1 mol % G+C. Phylogenetic analysis indicated that it was a member of the family Bacillaceae, Bacillus infernus and Bacillus firmus being the closest phylogenetic neighbours (having a mean similarity value of 96%); hence, strain COOI3B(T) is designated as a novel species, Bacillus subterraneus sp. nov.