Bacterial Growth Dynamics, Limiting Factors, and Community Diversity in a Proposed Geological Nuclear Waste Repository Environment

Horn, Joseph M.; Masterson, B.; Rivera, Aidsa; Miranda, Anabel; Davis, Michael A.; Martin, Stephen

doi:10.1080/01490450490438775

Cited by 16 publications

(16 citation statements)

References 30 publications

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“…Bacterial growth rates estimated in this paper reveal maximum turnover times of actively dividing cells, due to the fact that our counts of bacteria may also include inactive or dormant cells. Rates determined in this study are higher than those observed in other groundwaters (1.7-3.7 h) (Horn et al 2004), although it should be pointed out that the rates reported by this article were calculated under laboratory conditions, and possible temporal and spatial variabilities shown by microbial communities in natural systems, including aquifer systems (Goldscheider et al 2006), were therefore not taken into account. In river waters (33.2-71.5 h) (Fischer and Pusch 2001), river sediments (12.1-44.3 h) (Fischer and Pusch 2001) and shallow soil horizons (2.1-13.1 h) (Bååth 1998), bacterial growth rates have been described as being faster than those found in the aquifer system of Doñana.…”

Section: Microbiological Variablesmentioning

confidence: 78%

“…Curiously, these four piezometers grouped together in group 2 of the dendogram (Figure 2), showing that not only do they share similar microbiological characteristics, but also chemical and physical groundwater properties. In fact, it has been observed that high DOC concentration appears to promote protein synthesis in balanced growth (Kirchman and Rich 1997;Pulido-Villena and Reche 2003) and that phosphate significantly stimulates AMB, BCP and BGR (Horn et al 2004). Unfortunately, organic carbon concentrations were not determined in this study, but significant, positive relationships were found among SRP, TP, AMB, BCP and BGR.…”

Section: Factors Controlling Microbial Activities In Groundwater Temmentioning

confidence: 86%

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Microbial Activities in a Coastal, Sandy Aquifer System (Doñana Natural Protected Area, SW Spain)

Ayuso

López-Archilla

Montes

et al. 2010

Geomicrobiology Journal

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We conducted a seasonal research of the activities of microbial communities in a coastal, sandy aquifer system located in the Doñana Natural Protected Area (SW, Spain). Groundwaters from 30 piezometers were sampled over a two-year period. The proportion of active microbial biomass ranged from 0.02 to 6.36% of the total microbial biomass, while the active microbial biomass ranged from 7.42 × 10 −3 ± 2.20 × 10 −4 to 17.30 ± 3.71 ngC mL −1 . Bacterial carbon production, measured through the incorporation of [ 3 H]leucine into cellular proteins, showed a mean value of 0.18 ± 0.72 ngC mL −1 h −1 in all wells and all seasons. Bacterial growth rates ranged from 0.03 to 87.26 days. These activities exhibited spatiotemporal patterns. Temperature and the presence of nutrients and organic matter appear to be important factors controlling these patterns. However, hydrogeological flows, both local and regional, seemed to constitute the most important factor determining these spatiotemporal patterns, probably because the distribution of nutrients in aquifer systems is mainly controlled by these hydrogeological flows. The well-known hydrological flows connecting surface waters and groundwaters in Doñana support the assumption that both water compartments form a unique entity (called hydroecosystem), which functions as a whole. Consequently, not only microbial processes in surface waters can influence ecological processes in groundwaters, the characteristics of surface waters can also be affected by groundwater chemical processes, among others, mediated by the activities of microbial communities.

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Section: Microbiological Variablesmentioning

confidence: 78%

Section: Factors Controlling Microbial Activities In Groundwater Temmentioning

confidence: 86%

Microbial Activities in a Coastal, Sandy Aquifer System (Doñana Natural Protected Area, SW Spain)

Ayuso

López-Archilla

Montes

et al. 2010

Geomicrobiology Journal

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“…In unsaturated solids and sediments, water content influences nutrient diffusion, providing a major important constraint on microbial activity (Kieft et al 1993). In an investigation probing the effects of anticipated water infiltration from precipitation at some point during the lifetime of the repository, Horn et al (2004) demonstrated that despite P and C limitations, significant growth of aerobic chemoheterotrophic microorganisms, from 10 4 -10 5 to 8×10 6 cells mL −1 , occurred upon addition of a simulated groundwater without added organic carbon. In a finding consistent with the previous conclusions of Kieft et al (1997), the authors concluded that although the degree of water saturation was 86%, it appeared to be the primary factor limiting in situ microbial growth.…”

Section: Geomicrobial Considerations For Deep Subsurface Waste Reposimentioning

confidence: 98%

Geomicrobial Processes and Biodiversity in the Deep Terrestrial Subsurface

Fredrickson

Balkwill

2006

Geomicrobiology Journal

119

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The concept of a deep microbial biosphere has advanced over the past several decades from a hypothesis viewed with considerable skepticism to being widely accepted. Phylogenetically diverse prokaryotes have been cultured from or detected via characterization of directly-extracted nucleic acids from a wide range of deep terrestrial environments. Recent advances have linked the metabolic potential of these microorganisms, determined directly or inferred from phylogeny, to biogeochemical reactions determined via geochemical measurements and modeling. Buried organic matter or kerogen is an important source of energy for sustaining anaerobic heterotrophic microbial communities in deep sediments and sedimentary rock although rates of respiration are among the slowest rates measured on the planet. In contrast, Subsurface Lithoautotrophic Microbial Ecosystems based on H 2 as the primary energy source appear to dominate in many crystalline rock environments. These photosynthesis-independent ecosystems remain an enigma due to the difficulty in accessing and characterizing appropriate samples. Deep mines and dedicated rock laboratories, however, may offer unprecedented opportunities for investigating subsurface microbial communities and their interactions with the geosphere.

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“…These results are significant in that after about 1000 years following waste emplacement, groundwater is expected to drip into the repository environment. These experiments showed that significant microbial growth is possible when groundwater becomes available even absent of any added organic carbon (2).…”

Section: Present Ym Microbial Community and Limiting Factors To Growthmentioning

confidence: 93%

Microbial Effects on NuclearWaste Packaging Materials

Horn¹,

Martin²,

Carillo³

et al. 2005

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Bacterial Growth Dynamics, Limiting Factors, and Community Diversity in a Proposed Geological Nuclear Waste Repository Environment

Cited by 16 publications

References 30 publications

Microbial Activities in a Coastal, Sandy Aquifer System (Doñana Natural Protected Area, SW Spain)

Microbial Activities in a Coastal, Sandy Aquifer System (Doñana Natural Protected Area, SW Spain)

Geomicrobial Processes and Biodiversity in the Deep Terrestrial Subsurface

Microbial Effects on NuclearWaste Packaging Materials

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