The hadal biosphere: Recent insights and new directions

Liu, Rulong; Wang, Li; Wei, Yuli; Fang, Jiasong

doi:10.1016/j.dsr2.2017.04.015

Cited by 50 publications

(45 citation statements)

References 85 publications

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“…The abyssal plain extends from the continental slope to the rim of deep trenches (3000-6000 m below sea level [mbsl]) and covers 85% of the global seafloor area, while the hadal zone (>6000 mbsl) comprises 1-2% of it [1,2]. In general, abyssal water and sediments are usually oligotrophic, and physical and chemical conditions (e.g., salinity, temperature, dissolved oxygen, and nutrient concentrations) in hadal water are similar to the overlying abyssal water despite the higher hydrostatic pressure [1][2][3]. However, cell abundance and microbial carbon turnover rates are significantly higher at hadal trench bottom compared with abyssal plain sediment below the surface layer, while those in outermost surface layer are sometimes comparable between hadal and abyssal sites [4].…”

Section: Introductionmentioning

confidence: 99%

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

Hiraoka

Hirai

Matsui

et al. 2019

ISME J

107

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Hadal trench bottom (>6000 m below sea level) sediments harbor higher microbial cell abundance compared with 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 well 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 consortia that covaried across regions. Our results further support that the OM cycle is driven by hadal currents and/or rapid burial shapes microbial community structures at trench bottom sites, in addition to vertical deposition from the surface ocean. Our trans-trench analysis highlights intra-and inter-trench distributions of microbial assemblages and geochemistry in surface seafloor sediments, providing novel insights into ultradeep-sea microbial ecology, one of the last frontiers on our planet.

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Section: Introductionmentioning

confidence: 99%

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

Hiraoka

Hirai

Matsui

et al. 2019

ISME J

107

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“…It has been reported that the hadal trench is characterized by the extremely high hydrostatic pressure (>60 MPa) and isolated environments, while most of its physical and geochemical parameters such as temperature, salinity, and dissolved oxygen and organic carbon contents are similar with those from abyssal plains (4,000–6,000 mbsl) (Taira et al, 2005 ; Jamieson et al, 2010 ). In general, abundant heterotrophic microorganisms were detected in the hadal trenches, and heterotrophy is suggested to be enriched at greater depths of the trench axis due to the funneling effect resulting in an obvious accumulation of organic matters (Nunoura et al, 2015 ; Liu et al, 2017 ). Microbial transformation of bioavailable elements (e.g., carbon, nitrogen and sulfur) in hadal biosphere may have significant impact on global biogeochemical processes, and studies of these microorganisms would help to understand the microbial adaption strategies in this dark and high-pressure environment.…”

Section: Introductionmentioning

confidence: 99%

Metagenomics Reveals Microbial Diversity and Metabolic Potentials of Seawater and Surface Sediment From a Hadal Biosphere at the Yap Trench

et al. 2018

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Hadal biosphere represents the deepest part of the ocean with water depth >6,000 m. Accumulating evidence suggests the existence of unique microbial communities dominated by heterotrophic processes in this environment. However, investigations of the microbial diversity and their metabolic potentials are limited because of technical constraints for sample collection. Here, we provide a detailed metagenomic analysis of three seawater samples at water depths 5,000–6,000 m below sea level (mbsl) and three surface sediment samples at water depths 4,435–6,578 mbsl at the Yap Trench of the western Pacific. Distinct microbial community compositions were observed with the dominance of Gammaproteobacteria in seawater and Thaumarchaeota in surface sediment. Comparative analysis of the genes involved in carbon, nitrogen and sulfur metabolisms revealed that heterotrophic processes (i.e., degradation of carbohydrates, hydrocarbons, and aromatics) are the most common microbial metabolisms in the seawater, while chemolithoautotrophic metabolisms such as ammonia oxidation with the HP/HB cycle for CO2 fixation probably dominated the surface sediment communities of the Yap Trench. Furthermore, abundant genes involved in stress response and metal resistance were both detected in the seawater and sediments, thus the enrichment of metal resistance genes is further hypothesized to be characteristic of the hadal microbial communities. Overall, this study sheds light on the metabolic versatility of microorganisms in the Yap Trench, their roles in carbon, nitrogen, and sulfur biogeochemical cycles, and how they have adapted to this unique hadal environment.

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“…The abyssal plain extends from the continental slope to the rim of deep trenches (3,000–6,000 m below sea level [mbsl]) and covers 85% of the global seafloor area, while the hadal zone (>6,000 mbsl) comprises 1–2% of it [1, 2]. In general, abyssal water and sediments are usually oligotrophic, and physical and chemical conditions ( e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the influence of physicochemical features on hadal biospheres were reported for microbial communities in the Mariana and the Kermadec Trench regions under oligotrophic oceans [20, 21]. However, except for the cases, microbial community structures in hadal sediments were not compared with adjacent abyssal regions [2], and such comparison under eutrophic oceanic regions have not been investigated yet.…”

Section: Introductionmentioning

confidence: 99%

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

Hiraoka

Hirai

Matsui

et al. 2019

Preprint

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32Hadal trench bottom (>6,000 m below sea level) sediments harbor higher microbial cell abundance 33 compared to adjacent abyssal plain sediments. This is supported by the accumulation of sedimentary organic 34 matter (OM), facilitated by trench topography. However, the distribution of benthic microbes in different 35 trench systems has not been explored yet. Here, we carried out small subunit ribosomal RNA gene tag 36 sequencing for 92 sediment subsamples of seven abyssal and seven hadal sediment cores collected from three 37 trench regions in the northwest Pacific Ocean: the Japan, and Mariana Trenches. 38 Tag-sequencing analyses showed specific distribution patterns of several phyla associated with oxygen and 39 nitrate. The community structure was distinct between abyssal and hadal sediments, following geographic 40 locations and factors represented by sediment depth. Co-occurrence network revealed six potential prokaryotic 41 consortiums that covaried across regions. Our results further support that the endogenous OM cycle is driven 42 by hadal currents and/or rapid burial shapes microbial community structures at trench bottom sites, in addition 43 to vertical deposition from the surface ocean. Our trans-trench analysis highlights intra-and inter-trench 44 distributions of microbial assemblages and geochemistry in surface seafloor sediments, providing novel 45 insights into ultra-deep-sea microbial ecology, one of the last frontiers on our planet. 46 48The abyssal plain extends from the continental slope to the rim of deep trenches (3,000-6,000 m 49 below sea level [mbsl]) and covers 85% of the global seafloor area, while the hadal zone (>6,000 mbsl) 50 comprises 1-2% of it [1, 2]. In general, abyssal water and sediments are usually oligotrophic, and physical and 51 chemical conditions (e.g., salinity, temperature, dissolved oxygen, and nutrient concentrations) in hadal water 52 are similar to the overlying abyssal water despite the higher hydrostatic pressure [1-3]. However, cell 53 abundance and microbial carbon turnover rates are significantly higher at hadal compared to abyssal seafloors, 54 especially below the sediment surface, while microbial abundance in surface sediments are sometimes 55 comparable between hadal and abyssal sites [4]. This could be attributed to factors apart from differences in 56 the vertical downward flux of sinking organic matter (OM) from the ocean surface and hydrostatic pressure. 57Hadal zones are generally located in oceanic trenches that are formed along plate boundaries by 58 movement of oceanic plates, and thus experience episodic and/or regular landslides [5, 6]. These landslides 59 cause downward transportation of surface sediments along with relatively fresh OM via the funnel effect of 60 trench geomorphology [7][8][9][10][11]. Moreover, higher sedimentation rates and concentrations of subseafloor 61 organic compounds in trench bottom sediments compared to neighboring abyssal sediments have been 62 reported in multiple trench regions under oligotrophic and eutroph...

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The hadal biosphere: Recent insights and new directions

Cited by 50 publications

References 85 publications

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

Metagenomics Reveals Microbial Diversity and Metabolic Potentials of Seawater and Surface Sediment From a Hadal Biosphere at the Yap Trench

Microbial community and geochemical analyses of trans-trench sediments for understanding the roles of hadal environments

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