Abstract:Hydrothermal plumes transport reduced chemical species and metals into the open ocean. Despite their considerable spatial scale and impact on biogeochemical cycles, niche differentiation of abundant microbial clades is poorly understood. Here, we analyzed the microbial ecology of two bathy- (Brothers volcano; BrV-cone and northwest caldera; NWC) and a mesopelagic (Macauley volcano; McV) plumes on the Kermadec intra-oceanic arc in the South Pacific Ocean. The microbial community structure, determined by a combi… Show more
“…4A). This shift is in line with another recent study finding that different plume adapted specialized Gammaproteobacteria of SUP05 clade are characterized by a high expression of heavy-metal resistance (e.g., for avoiding cell encrustation) and Fe-acquisition genes and hence might be exclusively capable of dealing with such high Fe-levels 35 . The clear dominance of SUP05 in the original plume sample despite it's relatively low Fe contents (0.072 µM) could be interpreted to mean that most of the microbes in the plume were actually exported from near the vent, where mM Fe concentrations levels are frequently encountered in the dynamic environment at Brothers 45,46 .…”
Section: Discussionsupporting
confidence: 90%
“…Intriguingly, albeit Sulfurimonas and SUP05 are dominant affiliates in plume and other oxygen-poor waters, to date, they have not been directly associated with Fe-binding ligand production. Yet, a recent gene expression study suggested that the affiliates of the uncultured SUP05 have the genetic potential to oxidize Fe 35 . While clearly subordinate to the dominant SUP05 clade, a second group of Gammaproteobacteria of the genus Massilia (2.4-4.1%) are active in the 10 mM Fe-incubations.…”
Iron (Fe) is an essential trace element for life. In the ocean, Fe can be exceptionally scarce and thus biolimiting or extremely enriched causing microbial stress. The ability of hydrothermal plume microbes to counteract unfavorable Fe-concentrations up to 10 mM is investigated through experiments. While Campylobacterota (Sulfurimonas) are prominent in a diverse community at low to intermediate Fe-concentrations, the highest 10 mM Fe-level is phylogenetically less diverse and dominated by the SUP05 clade (Gammaproteobacteria), a species known to be genetically well equipped to strive in high-Fe environments. In all incubations, Fe-binding ligands were produced in excess of the corresponding Fe-concentration level, possibly facilitating biological Fe-uptake in low-Fe incubations and detoxification in high-Fe incubations. The diversity of Fe-containing formulae among dissolved organics (SPE-DOM) decreased with increasing Fe-concentration, which may reflect toxic conditions of the high-Fe treatments. A DOM-derived degradation index (IDEG) points to a degradation magnitude (microbial activity) that decreases with Fe and/or selective Fe-DOM coagulation. Our results show that some hydrothermal microbes (especially Gammaproteobacteria) have the capacity to thrive even at unfavorably high Fe-concentrations. These ligand-producing microbes could hence play a key role in keeping Fe in solution, particularly in environments, where Fe precipitation dominates and toxic conditions prevail.
“…4A). This shift is in line with another recent study finding that different plume adapted specialized Gammaproteobacteria of SUP05 clade are characterized by a high expression of heavy-metal resistance (e.g., for avoiding cell encrustation) and Fe-acquisition genes and hence might be exclusively capable of dealing with such high Fe-levels 35 . The clear dominance of SUP05 in the original plume sample despite it's relatively low Fe contents (0.072 µM) could be interpreted to mean that most of the microbes in the plume were actually exported from near the vent, where mM Fe concentrations levels are frequently encountered in the dynamic environment at Brothers 45,46 .…”
Section: Discussionsupporting
confidence: 90%
“…Intriguingly, albeit Sulfurimonas and SUP05 are dominant affiliates in plume and other oxygen-poor waters, to date, they have not been directly associated with Fe-binding ligand production. Yet, a recent gene expression study suggested that the affiliates of the uncultured SUP05 have the genetic potential to oxidize Fe 35 . While clearly subordinate to the dominant SUP05 clade, a second group of Gammaproteobacteria of the genus Massilia (2.4-4.1%) are active in the 10 mM Fe-incubations.…”
Iron (Fe) is an essential trace element for life. In the ocean, Fe can be exceptionally scarce and thus biolimiting or extremely enriched causing microbial stress. The ability of hydrothermal plume microbes to counteract unfavorable Fe-concentrations up to 10 mM is investigated through experiments. While Campylobacterota (Sulfurimonas) are prominent in a diverse community at low to intermediate Fe-concentrations, the highest 10 mM Fe-level is phylogenetically less diverse and dominated by the SUP05 clade (Gammaproteobacteria), a species known to be genetically well equipped to strive in high-Fe environments. In all incubations, Fe-binding ligands were produced in excess of the corresponding Fe-concentration level, possibly facilitating biological Fe-uptake in low-Fe incubations and detoxification in high-Fe incubations. The diversity of Fe-containing formulae among dissolved organics (SPE-DOM) decreased with increasing Fe-concentration, which may reflect toxic conditions of the high-Fe treatments. A DOM-derived degradation index (IDEG) points to a degradation magnitude (microbial activity) that decreases with Fe and/or selective Fe-DOM coagulation. Our results show that some hydrothermal microbes (especially Gammaproteobacteria) have the capacity to thrive even at unfavorably high Fe-concentrations. These ligand-producing microbes could hence play a key role in keeping Fe in solution, particularly in environments, where Fe precipitation dominates and toxic conditions prevail.
“…8 a), while overall highest relative abundances were observed throughout the year in the deeper suboxic waters of the basin in winter (up to 25% of the relative bacterial abundance). Members from the SUP05 clade are known chemolithoautotrophs and execute important roles in energy production in marine ecosystems including suboxic fjords 28 , deep ocean hydrothermal plumes 56 , 57 , and coastal shelf systems such as those off the West coast of Africa 58 . Figure 8 Seasonal trends for the chemoautotrophic SUP05 lineage in the Bedford Basin from 2014–2017.…”
Quantifying the temporal change of bacterial communities is essential to understanding how both natural and anthropogenic pressures impact the functions of coastal marine ecosystems. Here we use weekly microbial DNA sampling across four years to show that bacterial phyla have distinct seasonal niches, with a richness peak in winter (i.e., an inverse relationship with daylength). Our results suggest that seasonal fluctuations, rather than the kinetic energy or resource hypotheses, dominated the pattern of bacterial diversity. These findings supplement those from global analyses which lack temporal replication and present few data from winter months in polar and temperate regions. Centered log-ratio transformed data provided new insights into the seasonal niche partitioning of conditionally rare phyla, such as Modulibacteria, Verrucomicrobiota, Synergistota, Deinococcota, and Fermentibacterota. These patterns could not be identified using the standard practice of ASV generation followed by rarefaction. Our study provides evidence that five globally relevant ecotypes of chemolithoautotrophic bacteria from the SUP05 lineage comprise a significant functional group with varying seasonal dominance patterns in the Bedford Basin.
“…As they are characterized by a slower flow rate [77], the community could be expected to resemble the diluted diffusive flow, rich in heterotrophic bacteria [78]. Niua South plume samples, on the other hand, obtained from above the black smokers, reflect a typical community of a sulfide-rich plume with high abundance of SUP05 [27].…”
Section: Alcanivorax In Tonga Arc Plumesmentioning
Species within the genus Alcanivorax are well known hydrocarbon-degraders that propagate quickly in oil spills and natural oil seepage. They are also inhabitants of the deep-sea and have been found in several hydrothermal plumes. However, an in-depth analysis of deep-sea Alcanivorax is currently lacking. In this study, we used multiple culture-independent techniques to analyze the microbial community composition of hydrothermal plumes in the Northern Tonga arc and Northeastern Lau Basin focusing on the autecology of Alcanivorax. The hydrothermal vents feeding the plumes are hosted in an arc volcano (Niua), a rear-arc caldera (Niuatahi) and the Northeast Lau Spreading Centre (Maka). Fluorescence in situ hybridization revealed that Alcanivorax dominated the community at two sites (1210–1565 mbsl), reaching up to 48% relative abundance (3.5 × 104 cells/ml). Through 16S rRNA gene and metagenome analyses, we identified that this pattern was driven by two Alcanivorax species in the plumes of Niuatahi and Maka. Despite no indication for hydrocarbon presence in the plumes of these areas, a high expression of genes involved in hydrocarbon-degradation was observed. We hypothesize that the high abundance and gene expression of Alcanivorax is likely due to yet undiscovered hydrocarbon seepage from the seafloor, potentially resulting from recent volcanic activity in the area. Chain-length and complexity of hydrocarbons, and water depth could be driving niche partitioning in Alcanivorax.
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