Vertically distinct microbial communities in the Mariana and Kermadec trenches (original) (raw)
Related papers
Bulk and Active Sediment Prokaryotic Communities in the Mariana and Mussau Trenches
Frontiers in Microbiology, 2020
Surprisingly high rates of microbial respiration have recently been reported in hadal trench sediment, yet the potentially active microorganisms and specific microbemicrobe relationships in trench sediment are largely unknown. We investigated the bulk and active prokaryotic communities and co-occurrence interactions of different lineages in vertically sectioned sediment cores taken from the deepest points of the Mariana and Mussau Trenches. Analysis on species novelty revealed for the first time the high rate of novel lineages in the microbial communities of the hadal trenches. Using 95, 97, and 99% similarity as thresholds, averagely 22.29, 32.3, and 64.1% of total OTUs retrieved from sediments of the two trenches were identified as the potentially novel lineages, respectively. The compositions of the potentially active communities, revealed via ribosomal RNA (rRNA), were significantly different from those of bulk communities (rDNA) in all samples from both trenches. The dominant taxa in bulk communities generally accounted for low proportions in the rRNA libraries, signifying that the abundance was not necessarily related to community functions in the hadal sediments. The potentially active communities showed high diversity and composed primarily of heterotrophic lineages, supporting their potential contributions in organic carbon consumption. Network analysis revealed high modularity and non-random cooccurrence of phylogenetically unrelated taxa, indicating highly specified micro-niches and close microbial interactions in the hadal sediments tested. Combined analysis of activity potentials and network keystone scores revealed significance of phyla Chloroflexi and Gemmatimonadetes, as well as several potentially alkane-degrading taxa in maintaining microbial interactions and functions of the trench communities. Overall, our results demonstrate that the hadal trenches harbor diverse, closely interacting, and active microorganisms, despite the extreme environmental conditions.
Vertical Distribution of Microbial Eukaryotes From Surface to the Hadal Zone of the Mariana Trench
Frontiers in microbiology, 2018
Marine microbial eukaryotes are ubiquitous, comprised of phylogenetically diverse groups and play key roles in microbial food webs and global biogeochemical cycling. However, their vertical distribution in the deep sea has received little attention. In this study, we investigated the composition and diversity of the eukaryotes of both 0.2-3 μm and >3 μm size fractions from the surface to the hadal zone (8727 m) of the Mariana Trench using Illumina MiSeq sequencing for the 18S rDNA. The microbial eukaryotic community structure differed substantially across size fractions and depths. Operational taxonomic unit (OTU) richness in the >3 μm fraction was higher than that in the 0.2-3 μm fraction at the same depth. For the 0.2-3 μm fraction, sequences of Retaria (Rhizaria) were most abundant in the surface water (53.5%). Chrysophyceae (Stramenopiles) sequences dominated mostly in the samples from water depths below 1795 m. For the >3 μm fraction, sequences of Dinophyceae (Alveolat...
Microbial Diversity in Sediments from the Bottom of the Challenger Deep, the Mariana Trench
Microbes and Environments
The Challenger Deep is the deepest ocean on Earth. The present study investigated microbial community structures and geochemical cycles associated with the trench bottom sediments of the Challenger Deep, the Mariana Trench. The SSU rRNA gene communities found in trench bottom sediments were dominated by the bacteria Chloroflexi (SAR202 and other lineages), Bacteroidetes, Planctomycetes, "Ca. Marinimicrobia" (SAR406), and Gemmatimonadetes and by the archaeal α subgroup of MGI Thaumarchaeota and "Ca. Woesearchaeota" (Deep-sea Hydrothermal Vent Euryarchaeotic Group 6). The SSU rRNA gene sequencing analysis indicated that the dominant populations of the thaumarchaeal α group in hadal water and sediments were similar to each other at the species or genus level. In addition, the co-occurrence of nitrification and denitrification was revealed by the combination of pore water geochemical analyses and quantitative PCR for nitrifiers.
Microbial Community Diversity Within Sediments from Two Geographically Separated Hadal Trenches
Frontiers in Microbiology, 2019
Hadal ocean sediments, found at sites deeper than 6,000 m water depth, are thought to contain microbial communities distinct from those at shallower depths due to high hydrostatic pressures and higher abundances of organic matter. These communities may also differ from one other as a result of geographical isolation. Here we compare microbial community composition in surficial sediments of two hadal environments-the Mariana and Kermadec trenches-to evaluate microbial biogeography at hadal depths. Sediment microbial consortia were distinct between trenches, with higher relative sequence abundances of taxa previously correlated with organic matter degradation present in the Kermadec Trench. In contrast, the Mariana Trench, and deeper sediments in both trenches, were enriched in taxa predicted to break down recalcitrant material and contained other uncharacterized lineages. At the 97% similarity level, sequence-abundant taxa were not trench-specific and were related to those found in other hadal and abyssal habitats, indicating potential connectivity between geographically isolated sediments. Despite the diversity of microorganisms identified using culture-independent techniques, most isolates obtained under in situ pressures were related to previously identified piezophiles. Members related to these same taxa also became dominant community members when native sediments were incubated under static, long-term, unamended high-pressure conditions. Our results support the hypothesis that there is connectivity between sediment microbial populations inhabiting the Mariana and Kermadec trenches while showing that both whole communities and specific microbial lineages vary between trench of collection and sediment horizon depth. This in situ biodiversity is largely missed when incubating samples within pressure vessels and highlights the need for revised protocols for highpressure incubations.
Frontiers in microbiology, 2016
Relatively few studies have described the microbial populations present in ultra-deep hadal environments, largely as a result of difficulties associated with sampling. Here we report Illumina-tag V6 16S rRNA sequence-based analyses of the free-living and particle-associated microbial communities recovered from locations within two of the deepest hadal sites on Earth, the Challenger Deep (10,918 meters below surface-mbs) and the Sirena Deep (10,667 mbs) within the Mariana Trench, as well as one control site (Ulithi Atoll, 761 mbs). Seawater samples were collected using an autonomous lander positioned ~1 m above the seafloor. The bacterial populations within the Mariana Trench bottom water samples were dissimilar to other deep-sea microbial communities, though with overlap with those of diffuse flow hydrothermal vents and deep-subsurface locations. Distinct particle-associated and free-living bacterial communities were found to exist. The hadal bacterial populations were also markedly...
2019
Hadal trench bottom (>6,000 m below sea level) sediments harbor higher microbial cell abundance compared to adjacent abyssal plain sediments. This is supported by the accumulation of sedimentary organic matter (OM), facilitated by trench topography. However, the distribution of benthic microbes in different trench systems has not been explored yet. Here, we carried out small subunit ribosomal RNA gene tag sequencing for 92 sediment subsamples of seven abyssal and seven hadal sediment cores collected from three trench regions in the northwest Pacific Ocean: the Japan, Izu-Ogasawara, and Mariana Trenches. Tag-sequencing analyses showed specific distribution patterns of several phyla associated with oxygen and nitrate. The community structure was distinct between abyssal and hadal sediments, following geographic locations and factors represented by sediment depth. Co-occurrence network revealed six potential prokaryotic consortiums that covaried across regions. Our results further s...
High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth
Nature Geoscience, 2013
Microbes control the decomposition of organic matter in marine sediments. Decomposition, in turn, contributes to oceanic nutrient regeneration and influences the preservation of organic carbon 1 . Generally, rates of benthic decomposition decline with increasing water depth, although given the vast extent of the abyss, deep-sea sediments are quantitatively important for the global carbon cycle 2,3 . However, the deepest regions of the ocean have remained virtually unexplored 4 . Here, we present observations of microbial activity in sediments at Challenger Deep in the Mariana Trench in the central west Pacific, which at almost 11,000 m depth represents the deepest oceanic site on Earth. We used an autonomous micro-profiling system to assess benthic oxygen consumption rates. We show that although the presence of macrofauna is restricted at Challenger Deep, rates of biological consumption of oxygen are high, exceeding rates at a nearby 6,000-m-deep site by a factor of two. Consistently, analyses of sediments collected from the two sites reveal higher concentrations of microbial cells at Challenger Deep. Furthermore, analyses of sediment 210 Pb profiles reveal relatively high sediment deposition in the trench. We conclude that the elevated deposition of organic matter at Challenger Deep maintains intensified microbial activity at the extreme pressures that characterize this environment.
Environmental Microbiome
Background The Kuril–Kamchatka Trench (maximum depth 9604 m), located in the NW Pacific Ocean, is among the top seven deepest hadal trenches. The work aimed to investigate the unexplored abyssal-hadal prokaryotic communities of this fascinating, but underrated environment. Results As for the bacterial communities, we found that Proteobacteria (56.1–74.5%), Bacteroidetes (6.5–19.1%), and Actinobacteria (0.9–16.1%) were the most represented bacterial phyla over all samples. Thaumarchaeota (52.9–91.1%) was the most abundant phylum in the archaeal communities. The archaeal diversity was highly represented by the ammonia-oxidizing Nitrosopumilus, and the potential hydrocarbon-degrading bacteria Acinetobacter, Zhongshania, and Colwellia were the main bacterial genera. The α-diversity analysis evidenced that both prokaryotic communities were characterized by low evenness, as indicated by the high Gini index values (> 0.9). The β-diversity analysis (Redundancy Analysis) indicated that, a...
Hadal biosphere: Insight into the microbial ecosystem in the deepest ocean on Earth
Proceedings of the National Academy of Sciences of the United States of America, 2015
Hadal oceans at water depths below 6,000 m are the least-explored aquatic biosphere. The Challenger Deep, located in the western equatorial Pacific, with a water depth of ∼11 km, is the deepest ocean on Earth. Microbial communities associated with waters from the sea surface to the trench bottom (0 ∼10,257 m) in the Challenger Deep were analyzed, and unprecedented trench microbial communities were identified in the hadal waters (6,000 ∼10,257 m) that were distinct from the abyssal microbial communities. The potentially chemolithotrophic populations were less abundant in the hadal water than those in the upper abyssal waters. The emerging members of chemolithotrophic nitrifiers in the hadal water that likely adapt to the higher flux of electron donors were also different from those in the abyssal waters that adapt to the lower flux of electron donors. Species-level niche separation in most of the dominant taxa was also found between the hadal and abyssal microbial communities. Consid...