Submarine Basaltic Glass Colonization by the Heterotrophic Fe(II)-Oxidizing and Siderophore-Producing Deep-Sea Bacterium Pseudomonas stutzeri VS-10: The Potential Role of Basalt in Enhancing Growth

Abstract

Phylogenetically and metabolically diverse bacterial communities have been found in association with submarine basaltic glass surfaces. The driving forces behind basalt colonization are for the most part unknown. It remains ambiguous if basalt provides ecological advantages beyond representing a substrate for surface colonization, such as supplying nutrients and/or energy. Pseudomonas stutzeri VS-10, a metabolically versatile bacterium isolated from Vailulu’u Seamount, was used as a model organism to investigate the physiological responses observed when biofilms are established on basaltic glasses. In Fe-limited heterotrophic media, P. stutzeri VS-10 exhibited elevated growth in the presence of basaltic glass. Diffusion chamber experiments demonstrated that physical attachment or contact of soluble metabolites such as siderophores with the basaltic glass plays a pivotal role in this process. Electrochemical data indicated that P. stutzeri VS-10 is able to use solid substrates (electrodes) as terminal electron donors and acceptors. Siderophore production and heterotrophic Fe(II) oxidation are discussed as potential mechanisms enhancing growth of P. stutzeri VS-10 on glass surfaces. In correlation with that we discuss the possibility that metabolic versatility could represent a common and beneficial physiological trait in marine microbial communities being subject to oligotrophic and rapidly changing deep-sea conditions.

Sediment Microbial Communities Influenced by Cool Hydrothermal Fluid Migration

“…Sediments from Dorado Outcrop contained microbial communities that were also distinct from nearby (within a ∼2 km 2 area) seafloor-exposed basalts and bottom seawater ( Figures 3 , 6D ), indicating that substrate plays an important role in the selection of these communities. This agrees with numerous other studies which have demonstrated that solid mineral substrates select for microbes capable of respiring these materials, and geochemistry determines the community composition ( Templeton et al, 2005 ; Smith et al, 2011 ; Henri et al, 2016 ; Sudek et al, 2017 ). For instance, iron- and manganese-oxidizing bacteria are ubiquitous on marine basalts from active vents, and can be enriched on minerals found in basalts ( Templeton et al, 2005 ; Henri et al, 2016 ).…”

Experimental Microbial Alteration and Fe Mobilization From Basaltic Rocks of the ICDP HSDP2 Drill Core, Hilo, Hawaii

“…Simultaneous microbial dissolution of Fe(III) and Al(III) and an increased overall glass dissolution was also observed in colonization experiments during this study indicating the presence of microbial produced chelators. In another study Pseudomonas stutzeri VS-10 exhibited elevated growth in the presence of basaltic glass in Fe-limited heterotrophic media ( Sudek et al, 2017 ). We do not know if B. fungorum is capable of producing such metal specific chelators even if some authors suggest it.…”

“…It is well known that microorganisms are capable of producing organic acids and metal specific organic ligands to sequester essential nutrients ( Kraemer, 2004 ; Rogers and Bennett, 2004 ; Perez et al, 2016 ). Some metal-oxidizing bacteria are also able to biological catalyze Fe(II) or Mn(II) oxidation for energy gain ( Templeton et al, 2005 ; Bailey et al, 2009 ; Emerson et al, 2010 ; Henri et al, 2016 ; Sudek et al, 2017 ). However, there is still uncertainty about whether microorganisms actively scavenge elements from the rock or simply incorporate elements that are released by abiotic weathering processes ( Thorseth et al, 1992 , 1995a , b ; Templeton et al, 2009 ; Cockell et al, 2010 ; Stockmann et al, 2012 ; Ward et al, 2013 ).…”

“… Bailey et al (2009) have shown in laboratory experiments that microbes are able to obtain beneficial nutrients from basaltic glasses in a nutrient- and energy limiting environment. Furthermore, basaltic glasses are a potential habitat for Fe(II)-oxidizing microorganisms using Fe(II) in basaltic glasses as an energy source ( Henri et al, 2016 ; Sudek et al, 2017 ). Microbial oxidation of Fe(II) by different strains of Fe-oxidizing bacteria (FeOB) was found to enhance the dissolution of basaltic rocks by six to eight times over abiotic rates ( Edwards et al, 2004 ).…”

Formation and loss of metastable brucite: does Fe(II)-bearing brucite support microbial activity in serpentinizing ecosystems?

“…Fe(II) in brucite may serve as an electron donor when coupled with oxygen, nitrate or other powerful electron acceptors, similar to microbial Fe(II)-oxidation of basalts or olivine (e.g. [48][49][50]). Microbial Fe(II)-oxidation could be particularly prevalent in moderately alkaline Mg-HCO 3 − fluids (i.e.…”