Simple harpacticoid composition observed at deep hydrothermal vent sites on sea knoll calderas in the North-west Pacific

Author(s):  
Futa Nakasugi ◽  
Motohiro Shimanaga ◽  
Hidetaka Nomaki ◽  
Hiromi Kayama Watanabe ◽  
Tomo Kitahashi ◽  
...  

Abstract Dirivultid copepods (Siphonostomatoida), one of the most successful meiobenthic organisms found at deep-sea hydrothermal vents, have been the focus of most previous ecological studies among meiofauna in these habitats. The ecology of Harpacticoida, a major benthic copepod group in typical deep-sea floor, however, is not well understood in terms of variations in community structure and controlling factors at venting sites. The spatial heterogeneities in benthic harpacticoid composition and their association with environmental parameters were investigated at hydrothermal vent chimney structures in the calderas of three neighbouring sea knolls (Bayonnaise Knoll, Myojin Knoll and Myojin-sho Caldera) in the western North Pacific. While a previous study had reported the distribution of dirivultids was strongly associated with spatial differences in stable carbon isotopic signatures (δ13C) of organic matter in the detritus on active chimneys in the field, multivariate analyses detected no significant corelation between the parameter and harpacticoid composition in this study. Instead, high associations of the harpacticoid composition with differences in water depth and total organic carbon (TOC) concentration were detected. Ectinosomatidae dominated at vent sites with lower TOC values in the shallowest Bayonnaise Knoll, while they were less prevalent at deeper vent fields in the other knolls, where Miraciidae was the most abundant family. This study indicated the availability of vent chemoautotrophic carbon is not a primary factor controlling the composition of harpacticoids even in the habitats on the hydrothermal vents, but instead by the food amount, regardless of its resources (including marine snow from the sea surface), in the study area.

2010 ◽  
Vol 68 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Ana Colaço ◽  
Raul Bettencourt ◽  
Valentina Costa ◽  
Silvia Lino ◽  
Humberto Lopes ◽  
...  

AbstractColaço, A., Bettencourt, R., Costa, V., Lino, S., Lopes, H., Martins, I., Pires, L., Prieto, C., and Serrão Santos, R. 2011. LabHorta: a controlled aquarium system for monitoring physiological characteristics of the hydrothermal vent mussel Bathymodiolus azoricus. – ICES Journal of Marine Science, 68: 349–356. LabHorta is a facility composed of laboratories and retrievable deep-sea cages created to support and expand the capabilities of research cruises. It also enhances the ability to conduct experimental studies with organisms from deep-sea hydrothermal vents and other deep-sea environments, while keeping them under controlled conditions of pressure and water chemistry. This paper presents a case study with the vent mussel Bathymodiolus azoricus (which harbours a dual symbiosis) collected at the Menez Gwen hydrothermal vent field at 840-m depth, transported to experimental aquaria at atmospheric pressure and maintained under four different controlled experimental conditions to study their comparative condition index (CI). Environmental parameters were monitored daily and efforts were made to keep these constant. During the first few months, there were differences between the CI scores of mussels kept under the various conditions. After 6 months, the differences are not so clear but mussels still had sulphur-oxidizing bacteria when fed with sulphide. The methane oxidizer bacteria disappear even in the presence of methane. A range of CI scores appeared as a function of the culture type. The LabHorta facility is a good tool for performing long-term physiological studies of deep-sea organisms, simulating possible changes in the natural environmental where they normally thrive.


1997 ◽  
Vol 75 (2) ◽  
pp. 308-316 ◽  
Author(s):  
Marcel Le Pennec ◽  
Peter G. Beninger

To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.


2001 ◽  
Vol 67 (10) ◽  
pp. 4566-4572 ◽  
Author(s):  
Barbara J. Campbell ◽  
Christian Jeanthon ◽  
Joel E. Kostka ◽  
George W. Luther ◽  
S. Craig Cary

ABSTRACT Recent molecular characterizations of microbial communities from deep-sea hydrothermal sites indicate the predominance of bacteria belonging to the epsilon subdivision of Proteobacteria(epsilon Proteobacteria). Here, we report the first enrichments and characterizations of four epsilonProteobacteria that are directly associated withAlvinella pompejana, a deep sea hydrothermal vent polychete, or with hydrothermal vent chimney samples. These novel bacteria were moderately thermophilic sulfur-reducing heterotrophs growing on formate as the energy and carbon source. In addition, two of them (Am-H and Ex-18.2) could grow on sulfur lithoautrotrophically using hydrogen as the electron donor. Optimal growth temperatures of the bacteria ranged from 41 to 45°C. Phylogenetic analysis of the small-subunit ribosomal gene of the two heterotrophic bacteria demonstrated 95% similarity to Sulfurospirillum arcachonense, an epsilon Proteobacteria isolated from an oxidized marine surface sediment. The autotrophic bacteria grouped within a deeply branching clade of the epsilonProteobacteria, to date composed only of uncultured bacteria detected in a sample from a hydrothermal vent along the mid-Atlantic ridge. A molecular survey of various hydrothermal vent environments demonstrated the presence of two of these bacteria (Am-N and Am-H) in more than one geographic location and habitat. These results suggest that certain epsilonProteobacteria likely fill important niches in the environmental habitats of deep-sea hydrothermal vents, where they contribute to overall carbon and sulfur cycling at moderate thermophilic temperatures.


2020 ◽  
Author(s):  
Yi Lan ◽  
Jin Sun ◽  
Chong Chen ◽  
Yanan Sun ◽  
Yadong Zhou ◽  
...  

AbstractAnimals endemic to deep-sea hydrothermal vents often form obligatory relationships with bacterial symbionts, maintained by intricate host-symbiont interactions. Endosymbiosis with more than one symbiont is uncommon, and most genomic studies focusing on such ‘dual symbiosis’ systems have not investigated the host and the symbionts to a similar depth simultaneously. Here, we report a novel dual symbiosis among the peltospirid snail Gigantopelta aegis and its two Gammaproteobacteria endosymbionts – one being a sulphur oxidiser and the other a methane oxidiser. We assembled high-quality genomes for all three parties of this holobiont, with a chromosome-level assembly for the snail host (1.15 Gb, N50 = 82 Mb, 15 pseudo-chromosomes). In-depth analyses of these genomes reveal an intimate mutualistic relationship with complementarity in nutrition and metabolic codependency, resulting in a system highly versatile in transportation and utilisation of chemical energy. Moreover, G. aegis has an enhanced immune capability that likely facilitates the possession of more than one type of symbiont. Comparisons with Chrysomallon squamiferum, another chemosymbiotic snail in the same family but only with one sulphur-oxidising endosymbiont, show that the two snails’ sulphur-oxidising endosymbionts are phylogenetically distant, agreeing with previous results that the two snails have evolved endosymbiosis independently and convergently. Notably, the same capabilities of biosynthesis of specific nutrition lacking in the host genome are shared by the two sulphur-oxidising endosymbionts of the two snail genera, which may be a key criterion in the selection of symbionts by the hosts.


2017 ◽  
Author(s):  
James B. Bell ◽  
William D. K. Reid ◽  
David A. Pearce ◽  
Adrian G. Glover ◽  
Christopher J. Sweeting ◽  
...  

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.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7397 ◽  
Author(s):  
Andrew D. Thaler ◽  
Diva Amon

For over 40 years, hydrothermal vents and the communities that thrive on them have been a source of profound discovery for deep-sea ecologists. These ecosystems are found throughout the world on active plate margins as well as other geologically active features. In addition to their ecologic interest, hydrothermal vent fields are comprised of metallic ores, sparking a nascent industry that aims to mine these metal-rich deposits for their mineral wealth. Here, we provide the first systematic assessment of macrofaunal and megafaunal biodiversity at hydrothermal vents normalized against research effort. Cruise reports from scientific expeditions as well as other literature were used to characterize the extent of exploration, determine the relative biodiversity of different biogeographic provinces, identify knowledge gaps related to the distribution of research effort, and prioritize targets for additional sampling to establish biodiversity baselines ahead of potential commercial exploitation. The Northwest Pacific, Southwest Pacific, and Southern Ocean biogeographic provinces were identified as high biodiversity using rarefaction of family-level incidence data, whereas the North East Pacific Rise, Northern East Pacific, Mid-Atlantic Ridge, and Indian Ocean provinces had medium biodiversity, and the Mid-Cayman Spreading Center was identified as a province of relatively low biodiversity. A North/South divide in the extent of biological research and the targets of hydrothermal vent mining prospects was also identified. Finally, we provide an estimate of sampling completeness for each province to inform scientific and stewardship priorities.


Author(s):  
Yafei Chang ◽  
Qilian Fan ◽  
Jialin Hou ◽  
Yu Zhang ◽  
Jing Li

Abstract Microorganisms in deep-sea hydrothermal vents provide valuable insights into life under extreme conditions. Mass spectrometry-based proteomics has been widely used to identify protein expression and function. However, the metaproteomic studies in deep-sea microbiota have been constrained largely by the low identification rates of protein or peptide. To improve the efficiency of metaproteomics for hydrothermal vent microbiota, we firstly constructed a microbial gene database (HVentDB) based on 117 public metagenomic samples from hydrothermal vents and proposed a metaproteomic analysis strategy, which takes the advantages of not only the sample-matched metagenome, but also the metagenomic information released publicly in the community of hydrothermal vents. A two-stage false discovery rate method was followed up to control the risk of false positive. By applying our community-supported strategy to a hydrothermal vent sediment sample, about twice as many peptides were identified when compared with the ways against the sample-matched metagenome or the public reference database. In addition, more enriched and explainable taxonomic and functional profiles were detected by the HVentDB-based approach exclusively, as well as many important proteins involved in methane, amino acid, sugar, glycan metabolism and DNA repair, etc. The new metaproteomic analysis strategy will enhance our understanding of microbiota, including their lifestyles and metabolic capabilities in extreme environments. The database HVentDB is freely accessible from http://lilab.life.sjtu.edu.cn:8080/HventDB/main.html.


Zootaxa ◽  
2020 ◽  
Vol 4743 (1) ◽  
pp. 131-136 ◽  
Author(s):  
XINMING LIU ◽  
XINZHENG LI ◽  
RONGCHENG LIN

A new species of the genus Munida Leach, 1820, is described and illustrated based on a single specimen from the deep-sea hydrothermal vent on the Eastern Pacific Rise. Munida alba sp. nov. closely resembles M. ampliantennulata Komai, 2011, M. watatsumin Komai, 2014. and M. magniantennulata, but differences in the morphologies of the third maxilliped, pollex of the cheliped and the third segment of the antennal peduncle readily distinguish the new species from the three relatives. The new species is the fourth of the genus occurring at the hydrothermal vent areas. 


2017 ◽  
Vol 4 (4) ◽  
pp. 160829 ◽  
Author(s):  
Anni Djurhuus ◽  
Svein-Ole Mikalsen ◽  
Helge-Ansgar Giebel ◽  
Alex D. Rogers

There are still notable gaps regarding the detailed distribution of microorganisms between and within insular habitats such as deep-sea hydrothermal vents. This study investigates the community composition of black smoker vent microorganisms in the Southern Hemisphere, and changes thereof along a spatial and chemical gradient ranging from the vent plume to surrounding waters. We sampled two hydrothermal vent fields, one at the South West Indian Ridge (SWIR), the other at the East Scotia Ridge (ESR). Samples were collected across vent fields at varying vertical distances from the origin of the plumes. The microbial data were sequenced on an Illumina MiSeq platform for the 16SrRNA gene. A substantial amount of vent-specific putative chemosynthetic microorganisms were found, particularly in samples from focused hydrothermal venting. Common vent-specific organisms from both vent fields were the genera Arcobacter , Caminibacter and Sulfurimonas from the Epsilonproteobacteria and the SUP05 group from the Gammaproteobacteria. There were no major differences in microbial composition between SWIR and ESR for focused plume samples. However, within the ESR the diffuse flow and focused samples differed significantly in microbial community composition and relative abundance. For Epsilonproteobacteria, we found evidence of niche-specificity to hydrothermal vent environments. This taxon decreased in abundance by three orders of magnitude from the vent orifice to background water. Epsilonproteobacteria distribution followed a distance–decay relationship as vent-effluents mixed with the surrounding seawater. This study demonstrates strong habitat affinity of vent microorganisms on a metre scale with distinct environmental selection.


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