scholarly journals Post-drilling research of IODP Expedition 331: a test-bed for anthropogenic impacts and experiments on deep-sea hydrothermal activity and ecosystem

2017 ◽  
Vol 123 (4) ◽  
pp. 225-235
Author(s):  
Ken Takai
Keyword(s):  
Deep Sea ◽  
Anthropogenic Impacts ◽  
Hydrothermal Activity ◽  
Test Bed

scholarly journals Hydrothermal activity lowers trophic diversity in Antarctic sedimented hydrothermal vents

2017 ◽  
Author(s):  
James B. Bell ◽  
William D. K. Reid ◽  
David A. Pearce ◽  
Adrian G. Glover ◽  
Christopher J. Sweeting ◽  
...  
Keyword(s):  
Active Site ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Hydrothermal Activity ◽  
Feeding Strategies ◽  
Microbial Composition ◽  
Isotopic Signatures ◽  
Structure Morphology ◽  
Feeding Structure ◽  
Niche Area

Abstract. Sedimented hydrothermal vents are those in which hydrothermal fluid is discharged through sediments and are among the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermally active and off-vent areas of the Bransfield Strait (1050–1647 m depth). Microbial composition, biomass and fatty acid signatures varied widely between and within vent and non-vent sites and provided evidence of diverse metabolic activity. Several species showed diverse feeding strategies and occupied different trophic positions in vent and nonvent areas. Stable isotope values of consumers were generally not consistent with feeding structure morphology. Niche area and the diversity of microbial fatty acids reflected trends in species diversity and was lowest at the most hydrothermally active site. Faunal utilisation of chemosynthetic activity was relatively limited but was detected at both vent and non-vent sites as evidenced by carbon and sulphur isotopic signatures, suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.

scholarly journals Fabrication of an All-Solid-State Carbonate Ion-Selective Electrode with Carbon Film as Transducer and Its Preliminary Application in Deep-Sea Hydrothermal Field Exploration

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 236
Author(s):  
Chuqing Zhang ◽  
Yang He ◽  
Jianbo Wu ◽  
Manqing Ai ◽  
Wei Cai ◽  
...  
Keyword(s):  
Deep Sea ◽  
Carbon Film ◽  
Hydrothermal Activity ◽  
Electrochemical Analysis ◽  
Southwest Indian Ridge ◽  
Ion Selective Electrode ◽  
Hydrothermal Field ◽  
Selective Electrode ◽  
Carbonate Ion ◽  
Selective Membrane

Real-time measurements of carbonate ion concentrations in the ocean are critical to advancing marine environmental monitoring and research into deep-sea hydrothermal activity. Herein, we report the first example of deep-sea hydrothermal field exploration using a carbonate ion-selective electrode (ISE). The novel carbonate ISE was composed of a Ni wire as substrate, carbon film as transducers and carbonate-selective membrane layers. This paper describes the preparation process of the electrode and characterises its performance via scanning electron microscopy (SEM) and electrochemical analysis. The detection limit of the electrode for CO32− is 2.821 × 10−6 mol/L, the linear response range is 1.0 × 10−5–1.0 × 10−1 mol/L and the Nernst slope was −30.4 mV/decade. In April 2021, the carbonate ISE was mounted on multi-parameter sensors with pH and Eh (redox) electrodes for the search of hydrothermal activity at the Southwest Indian Ridge. The simultaneous potential anomalies appeared at this carbonate electrode with the pH and Eh electrodes when passing through the hydrothermal field. The study of the hydrothermal field was supported by the in situ camera video and the sulphide samples. Additionally, the carbonate electrode provides enhanced information of water chemistry for the study of the hydrothermal field.

scholarly journals Microbial succession during the transition from active to inactive stages of deep-sea hydrothermal vent sulfide chimneys

2020 ◽  
Author(s):  
Jialin Hou ◽  
Stefan M. Sievert ◽  
Yinzhao Wang ◽  
Jeff S. Seewald ◽  
Vengadesh Perumal Natarajan ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Iron Oxidation ◽  
Deep Ocean ◽  
Hydrothermal Activity ◽  
Nitrite Reduction ◽  
Rrna Gene ◽  
Microbial Succession ◽  
Primary Producers ◽  
Bacterial Phyla

Abstract Background: Deep-sea hydrothermal vents are highly productive biodiversity hotspots in the deep ocean supported by chemosynthetic microorganisms. Prominent features of these systems are sulfide chimneys emanating high temperature hydrothermal fluids. While several studies have investigated the microbial diversity in both active and inactive sulfide chimneys that have been extinct for up to thousands of years, little is known about chimneys that have ceased activity more recently, as well as the microbial succession occurring during the transition from active to inactive chimneys. Results: Genome-resolved metagenomics was applied to an active and a recently extinct (~7 years) sulfide chimney from the 9°-10°N hydrothermal vent field on the East Pacific Rise. Full-length 16S rRNA gene and a total of 173 high quality metagenome assembled genomes (MAGs) were retrieved for comparative analysis. In the active chimney (L-vent), sulfide- and/or hydrogen-oxidizing Campylobacteria and Aquificae with the potential for denitrification were identified as the dominant community members and primary producers, fixing carbon through the reductive tricarboxylic acid (rTCA) cycle. In contrast, the microbiome of the recently extinct chimney (M-vent) was largely composed of heterotrophs from various bacterial phyla, including Delta -/ Beta -/ Alphaproteobacteria and Bacteroidetes . Gammaproteobacteria were identified as the main primary producers, using the oxidation of metal sulfides and/or iron oxidation coupled to nitrate reduction to fix carbon through the Calvin-Benson-Bassham (CBB) cycle. Further analysis revealed a phylogenetically distinct Nitrospirae cluster that has the potential to oxidize sulfide minerals coupled to oxygen and/or nitrite reduction, as well as for sulfate reduction, and that might serve as an indicator for the early stages of chimneys after venting has ceased. Conclusions: This study sheds light on the composition, metabolic functions, and succession of microbial communities inhabiting deep-sea hydrothermal vent sulfide chimneys. Collectively, microbial succession during the life span of a chimney could be described to proceed from a “fluid-shaped” microbial community in newly formed and actively venting chimneys supported by the oxidation of reductants in the hydrothermal fluid to a “mineral-shaped” community supported by the oxidation of minerals after hydrothermal activity has ceased. Remarkably, the transition appears to occur within the first few years, after which the communities stay stable for thousands of years.

Tide-related variability of TAG hydrothermal activity observed by deep-sea monitoring system and OBSH

1997 ◽  
Vol 153 (3-4) ◽  
pp. 239-250 ◽  
Author(s):  
Kantaro Fujioka ◽  
Kazuo Kobayashi ◽  
Kazuhiro Kato ◽  
Misumi Aoki ◽  
Kyohiko Mitsuzawa ◽  
...  
Keyword(s):  
Monitoring System ◽  
Deep Sea ◽  
Hydrothermal Activity

Biodiversity, community structure and ecosystem function on kelp and wood falls in the Norwegian deep sea

2021 ◽  
Vol 657 ◽  
pp. 73-91
Author(s):  
RP Harbour ◽  
CR Smith ◽  
C Simon-Nutbrown ◽  
M Cecchetto ◽  
E Young ◽  
...  
Keyword(s):  
Community Structure ◽  
Ecosystem Function ◽  
Deep Sea ◽  
Ecosystem Functioning ◽  
Secondary Production ◽  
Anthropogenic Impacts ◽  
Management Strategies ◽  
Terrestrial Ecosystems ◽  
Kelp Forests ◽  
Biological Trait

Fjordic systems in temperate and Arctic regions often feature extensive kelp forests at their shallow coastal margins as well as extensive terrestrial forests. Detrital export from these shallow-water and terrestrial ecosystems is an important source of carbon for deep-sea communities in the form of kelp and wood falls. Benthic landers with experimental substrates (wood blocks and kelp parcels) were deployed for 10 mo at a depth of 530 m in a deep Norwegian fjord to investigate and compare macro- and megabenthic community structure, biodiversity and ecosystem functioning on kelp and wood falls. Results revealed that while wood and kelp falls can support a similar number of species and abundance of fauna, they support significantly different faunal communities. Biomass and secondary production on both wood and kelp substrates were significantly greater than in the control samples. Secondary production estimates were similar or higher than those reported from soft-sediment ecosystems at shallower European marine sites. Biological trait analysis showed that macrofaunal assemblages were distinct between the kelp and wood, providing evidence for differences in ecosystem function between the substrates. This case study from a deep-sea fjord in Norway provides clear evidence that while wood and kelp organic falls can support similar abundances of fauna, the associated benthic biodiversity, community structure and ecosystem functioning can be dramatically different between these substrates. The work presented here aims to provide information that is useful in assessing the extent of anthropogenic impacts on deep fjord ecosystems with respect to informing future conservation and management strategies.

scholarly journals Species variability and connectivity in the deep sea: evaluating effects of spatial heterogeneity and hydrodynamics

2016 ◽  
Author(s):  
Lidia Lins ◽  
Frederik Leliaert ◽  
Torben Riehl ◽  
Sofia Pinto Ramalho ◽  
Eliana Alfaro Cordova ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Deep Sea ◽  
Beta Diversity ◽  
Species Coexistence ◽  
Anthropogenic Impacts ◽  
Alpha Diversity ◽  
Continental Margins ◽  
Alpha And Beta Diversity ◽  
Different Depths ◽  
Hydrodynamic Effects

Abstract. Understanding processes responsible for shaping biodiversity patterns on continental margins is an important requirement for comprehending anthropogenic impacts in these environments. Continental margins perform crucial functions which are mainly structured by hydrodynamic effects and surface primary productivity. However, to what extent these processes control benthic local and regional biodiversity remains unclear. In this study, we focused on two isobathic parallel transects to test if food resources arriving at the seafloor and hydrodynamic effects affect alpha and beta diversity at different depths in similar ways. We also examined the potential role of connectivity between both depths as a result of dispersal. This is the first study applying integrative approaches using molecular and morphological techniques in combination with environmental factors to unravel spatial variability and connectivity in relation to depth in the deep sea. Results revealed that high variability in resource availability is directly linked to high alpha diversity and spatial heterogeneity, and that communities dwelling in deeper regions are able to use resources complementarily promoting species coexistence. Our study also demonstrated that higher hydrodynamics at the shallower habitats near the shelf break, as inferred from the high sediment heterogeneity, promoted variation in community structure across stations (higher beta diversity) compared to the deeper area. In addition, phylogenetic relationships revealed no evidence for depth-endemic lineages or isolation per habitat, indicating regular species interchanges across different depths.

scholarly journals From sea surface to seafloor: a benthic allochthonous eDNA survey for the abyssal ocean

2020 ◽  
Author(s):  
Olivier Laroche ◽  
Oliver Kersten ◽  
Craig R. Smith ◽  
Erica Goetze
Keyword(s):  
Water Column ◽  
Deep Sea ◽  
Anthropogenic Impacts ◽  
Spatial Scales ◽  
Deep Ocean ◽  
Environmental Dna ◽  
Benthic Boundary Layer ◽  
Large Sample Size ◽  
Polymetallic Nodule ◽  
Nodule Mining

AbstractDiverse and remote deep-sea communities are critically under-sampled and increasingly threatened by anthropogenic impacts. Environmental DNA (eDNA) metabarcoding could facilitate rapid and comprehensive biotic surveys in the deep ocean, yet many aspects of the sources and distribution of eDNA in the deep sea are still poorly understood. In order to examine the influence of the water column on benthic eDNA surveys in regions targeted for deep-sea polymetallic nodule mining, we investigated the occurrence of pelagic eDNA across: (1) two different deep-sea habitat types, abyssal plains and seamounts, (2) benthic sample types, including nodules, sediment, and seawater within the benthic boundary layer (BBL), and (3) sediment depth horizons (0-2 cm, 3-5 cm). Little difference was observed between seamounts and the adjacent abyssal plains in the proportion of legacy pelagic eDNA sampled in the benthos, despite an > 1000 m depth difference for these habitats. In terms of both reads and amplicon sequence variants (ASVs), pelagic eDNA was minimal within sediment and nodule samples (< 2%), and is unlikely to affect benthic surveys that monitor resident organisms at the deep seafloor. However, pelagic eDNA was substantial within the BBL (up to 13 % ASVs, 86% reads), deriving both from the high biomass upper ocean as well as deep pelagic residents. While most pelagic eDNA found in sediments and on nodules could be sourced from the epipelagic for metazoans, protist legacy eDNA sampled on these substrates appeared to originate across a range of depths in the water column. Some evidence of eDNA degradation across a vertical sediment profile was observed for protists, with higher diversity in the 0-2 cm layer and a significantly lower proportion of legacy pelagic eDNA in deeper sediments (3-5 cm). Study-wide, our estimated metazoan sampling coverage ranged from 40% to 74%, despite relatively large sample size. Future deep-sea eDNA surveys should examine oceanographic influences on eDNA transport and residence times, consider habitat heterogeneity at a range of spatial scales in the abyss, and aim to process large amounts of material per sample (with replication) in order to increase the sampling coverage in these diverse deep ocean communities.

scholarly journals Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments

2017 ◽  
Vol 14 (24) ◽  
pp. 5705-5725 ◽  
Author(s):  
James B. Bell ◽  
William D. K. Reid ◽  
David A. Pearce ◽  
Adrian G. Glover ◽  
Christopher J. Sweeting ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Active Site ◽  
Deep Sea ◽  
Hydrothermal Fluid ◽  
Hydrothermal Activity ◽  
Feeding Strategies ◽  
Microbial Composition ◽  
Hydrothermal Sediments ◽  
Niche Area

Abstract. Hydrothermal sediments are those in which hydrothermal fluid is discharged through sediments and are one of the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermal and background areas of the Bransfield Strait (1050–1647 m of depth). Microbial composition, biomass, and fatty acid signatures varied widely between and within hydrothermally active and background sites, providing evidence of diverse metabolic activity. Several species had different feeding strategies and trophic positions between hydrothermally active and inactive areas, and the stable isotope values of consumers were not consistent with feeding morphology. Niche area and the diversity of microbial fatty acids was lowest at the most hydrothermally active site, reflecting trends in species diversity. Faunal uptake of chemosynthetically produced organics was relatively limited but was detected at both hydrothermal and non-hydrothermal sites, potentially suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.

Sign in / Sign up

Export Citation Format

Share Document