scholarly journals Marine sediments illuminate Chlamydiae diversity and evolution

2019 ◽  
Author(s):  
Jennah E. Dharamshi ◽  
Daniel Tamarit ◽  
Laura Eme ◽  
Courtney Stairs ◽  
Joran Martijn ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Genomic Diversity ◽  
The Arctic ◽  
Community Members ◽  
Environmental Distribution ◽  
Microbial Eukaryotes ◽  
Sister Clade ◽  
Animal Pathogens ◽  
Abundance And Diversity ◽  
Ocean Ridge

The bacterial phylum Chlamydiae, which is so far comprised of obligate symbionts of eukaryotic hosts, are well-known as human and animal pathogens1-3. However, the Chlamydiae also include so-called environmental lineages4-6that primarily infect microbial eukaryotes7. Studying environmental chlamydiae, whose genomes display extended metabolic capabilities compared to their pathogenic relatives8-10has provided first insights into the evolution of the pathogenic and obligate intracellular lifestyle that is characteristic for this phylum. Here, we report an unprecedented relative abundance and diversity of novel lineages of the Chlamydiae phylum, representing previously undetected, yet potentially important, community members in deep marine sediments. We discovered that chlamydial lineages dominate the microbial communities in the Arctic Mid-Ocean Ridge11, which revealed the dominance of chlamydial lineages at anoxic depths, reaching relative abundances of up to 43% of the bacterial community, and a maximum diversity of 163 different species-level taxonomic unit. Using genome-resolved metagenomics, we reconstructed 24 draft chlamydial genomes, thereby dramatically expanding known interspecies genomic diversity in this phylum. Phylogenomic and comparative analyses revealed several deep-branching Chlamydiae clades, including a sister clade of the pathogenic Chlamydiaceae. Altogether, our study provides new insights into the diversity, evolution and environmental distribution of the Chlamydiae.

scholarly journals Genomic diversity and biosynthetic capabilities of sponge-associated chlamydiae

2021 ◽  
Author(s):  
Jennah E. Dharamshi ◽  
Natalia Gaarslev ◽  
Karin Steffen ◽  
Tom Martin ◽  
Detmer Sipkema ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Marine Invertebrates ◽  
Genomic Diversity ◽  
Host Interactions ◽  
Obligate Intracellular ◽  
Microbial Eukaryotes ◽  
Animal Pathogens ◽  
Host Health ◽  
Obligate Intracellular Bacteria

Sponge microbiomes contribute to host health, nutrition, and defense through the production of secondary metabolites. Chlamydiae, a phylum of obligate intracellular bacteria ranging from animal pathogens to endosymbionts of microbial eukaryotes, are frequently found associated with sponges. However, sponge-associated chlamydial diversity has not yet been investigated at the genomic level and host-interactions remain thus far unexplored. Here, we sequenced the microbiomes of three sponge species and found high, though variable, Chlamydiae relative abundances of up to 21.2% of bacterial diversity. Using genome-resolved metagenomics 18 high-quality sponge-associated chlamydial genomes were reconstructed, covering four chlamydial families. Among these, Sorochlamydiaceae shares a common ancestor with Chlamydiaceae animal pathogens, suggesting long-term co-evolution with animals. Sponge-associated chlamydiae genomes mostly resembled environmental chlamydial endosymbionts, but not pathogens, and encoded genes for degrading diverse compounds associated with sponges, such as taurine. Unexpectedly, we identified widespread genetic potential for secondary metabolite biosynthesis across Chlamydiae, which may represent an explored reservoir of novel natural products. This finding suggests that chlamydiae may partake in defensive symbioses and that secondary metabolites play a wider role in mediating intracellular interactions. Furthermore, sponge-associated chlamydiae relatives were found in other marine invertebrates, pointing towards wider impacts of this phylum on marine ecosystems.

scholarly journals Preliminary Screening for Microplastic Concentrations in the Surface Water of the Ob and Tom Rivers in Siberia, Russia

2020 ◽  
Vol 13 (1) ◽  
pp. 80
Author(s):  
Yulia A. Frank ◽  
Egor D. Vorobiev ◽  
Danil S. Vorobiev ◽  
Andrey A. Trifonov ◽  
Dmitry V. Antsiferov ◽  
...  
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
River System ◽  
The Arctic ◽  
Preliminary Screening ◽  
Freshwater Systems ◽  
Ob River ◽  
The Arctic Ocean ◽  
Abundance And Diversity ◽  
Blank Spot

To date, the largest Russian rivers discharging to the Arctic Ocean remain a “blank spot” on the world map of data on the distribution of microplastics in freshwater systems. This study characterizes the abundance and morphology of microplastics in surface water of the Ob River and its large tributary, the Tom River, in western Siberia. The average number of particles for the two rivers ranged from 44.2 to 51.2 items per m3 or from 79.4 to 87.5 μg per m3 in the Tom River and in the Ob River, respectively. Of the recovered microplastics, 93.5% were less than 1 mm in their largest dimension, the largest group (45.5% of total counts) consisted of particles with sizes range 0.30–1.00 mm. Generally, microfragments of irregular shape were the most abundant among the Ob and Tom samples (47.4%) and exceeded microfibers (22.1%), microfilms (20.8%), and microspheres (9.74%) by average counts. Results from this study provide a baseline for understanding the scale of the transport of microplastics by the Ob River system into the Arctic Ocean and add to currently available data on microplastics abundance and diversity in freshwater systems of differing global geographic locations.

scholarly journals A subduction influence on ocean ridge basalts outside the Pacific subduction shield

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
A. Y. Yang ◽  
C. H. Langmuir ◽  
Y. Cai ◽  
P. Michael ◽  
S. L. Goldstein ◽  
...  
Keyword(s):  
Upper Mantle ◽  
The Arctic ◽  
Mantle Flow ◽  
Mantle Heterogeneity ◽  
Gakkel Ridge ◽  
The Pacific ◽  
Mid Ocean Ridge ◽  
The Pacific Ocean ◽  
Back Arc ◽  
Ocean Ridge

AbstractThe plate tectonic cycle produces chemically distinct mid-ocean ridge basalts and arc volcanics, with the latter enriched in elements such as Ba, Rb, Th, Sr and Pb and depleted in Nb owing to the water-rich flux from the subducted slab. Basalts from back-arc basins, with intermediate compositions, show that such a slab flux can be transported behind the volcanic front of the arc and incorporated into mantle flow. Hence it is puzzling why melts of subduction-modified mantle have rarely been recognized in mid-ocean ridge basalts. Here we report the first mid-ocean ridge basalt samples with distinct arc signatures, akin to back-arc basin basalts, from the Arctic Gakkel Ridge. A new high precision dataset for 576 Gakkel samples suggests a pervasive subduction influence in this region. This influence can also be identified in Atlantic and Indian mid-ocean ridge basalts but is nearly absent in Pacific mid-ocean ridge basalts. Such a hemispheric-scale upper mantle heterogeneity reflects subduction modification of the asthenospheric mantle which is incorporated into mantle flow, and whose geographical distribution is controlled dominantly by a “subduction shield” that has surrounded the Pacific Ocean for 180 Myr. Simple modeling suggests that a slab flux equivalent to ~13% of the output at arcs is incorporated into the convecting upper mantle.

scholarly journals An inter-laboratory investigation of the Arctic sea ice biomarker proxy IP<sub>25</sub> in marine sediments: key outcomes and recommendations

2014 ◽  
Vol 10 (1) ◽  
pp. 155-166 ◽  
Author(s):  
S. T. Belt ◽  
T. A. Brown ◽  
L. Ampel ◽  
P. Cabedo-Sanz ◽  
K. Fahl ◽  
...  
Keyword(s):  
Sea Ice ◽  
Laboratory Investigation ◽  
Marine Sediments ◽  
Instrumental Response ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Response Factors ◽  
Arctic Sea

Abstract. We describe the results of an inter-laboratory investigation into the identification and quantification of the Arctic sea ice biomarker proxy IP25 in marine sediments. Seven laboratories took part in the study, which consisted of the analysis of IP25 in a series of sediment samples from different regions of the Arctic, sub-Arctic and Antarctic, additional sediment extracts and purified standards. The results obtained allowed 4 key outcomes to be determined. First, IP25 was identified by all laboratories in sediments from the Canadian Arctic with inter-laboratory variation in IP25 concentration being substantially larger than within individual laboratories. This greater variation between laboratories was attributed to the difficulty in accurately determining instrumental response factors for IP25, even though laboratories were supplied with appropriate standards. Second, the identification of IP25 by 3 laboratories in sediment from SW Iceland that was believed to represent a blank, was interpreted as representing a better limit of detection or quantification for such laboratories, contamination or mis-identification. These alternatives could not be distinguished conclusively with the data available, although it is noted that the precision of these data was significantly poorer compared with the other IP25 concentration measurements. Third, 3 laboratories reported the occurrence of IP25 in a sediment sample from the Antarctic Peninsula even though this biomarker is believed to be absent from the Southern Ocean. This anomaly is attributed to a combined chromatographic and mass spectrometric interference that results from the presence of a di-unsaturated highly branched isoprenoid (HBI) pseudo-homologue of IP25 that occurs in Antarctic sediments. Finally, data are presented that suggest that extraction of IP25 is consistent between Accelerated Solvent Extraction (ASE) and sonication methods and that IP25 concentrations based on 7-hexylnonadecane as an internal standard are comparable using these methods. Recoveries of some more unsaturated HBIs and the internal standard 9-octylheptadecene, however, were lower with the ASE procedure, possibly due to partial degradation of these more reactive chemicals as a result of higher temperatures employed with this method. For future measurements, we recommend the use of reference sediment material with known concentration(s) of IP25 for determining and routinely monitoring instrumental response factors. Given the significance placed on the presence (or otherwise) of IP25 in marine sediments, some further recommendations pertaining to quality control are made that should also enable the two main anomalies identified here to be addressed.

Community dynamics in Fijian coral reef fish communities vary with conservation and shark-based tourism

2019 ◽  
Vol 25 (4) ◽  
pp. 363
Author(s):  
Mallory G. McKeon ◽  
Joshua A. Drew
Keyword(s):  
Community Dynamics ◽  
Local Community ◽  
Census Data ◽  
Fish Abundance ◽  
Full Potential ◽  
Community Members ◽  
Composition And Structure ◽  
Feeding Methods ◽  
Abundance And Diversity ◽  
Unprotected Area

Marine protected areas (MPAs) effectively improve the biomass and diversity in heavily exploited marine systems, but often fail to reach their full potential because they require more space, time, and consistency of regulation. Recently, shark-based tourism, which utilises some of the remaining shark strongholds as tourism hotspots, has brought about increased awareness to exploited reef systems. In Fiji, specifically, shark diving companies include local community members in their operations to promote better understanding of their reefs. We seek to investigate whether seemingly denser shark populations during feeding times influence community composition and structure. Visual census data were collected from 50-m belt transects at four different reefs in Fiji: two MPAs with shark-based ecotourism with food provisioning, one MPA without shark-based ecotourism, and one unprotected area without shark-based tourism. Paradoxically, indices of evenness and diversity were highest in the non-protected site. However, there was significantly higher fish abundance and species diversity within reserves than outside of reserves. Within reserves, sites with shark feeding had lower fish abundance and higher richness, diversity, and evenness. Mean trophic level was highest at sites with shark feeding. Use of chum increased average fish abundance and diversity within shark-dive sites. These results indicate that there are evident differences between MPAs that do and do not offer trophic supplementation for shark-based ecotourism. Thus, tourism may be facilitating a shift of ecosystem composition in such areas. Furthermore, the results suggest that feeding methods may augment the impacts of shark-based tourism on the reef at large.

Rhabdothermus arcticus gen. nov., sp. nov., a member of the family Thermaceae isolated from a hydrothermal vent chimney in the Soria Moria vent field on the Arctic Mid-Ocean Ridge

2011 ◽  
Vol 61 (9) ◽  
pp. 2197-2204 ◽  
Author(s):  
Bjørn O. Steinsbu ◽  
Brian J. Tindall ◽  
Vigdis L. Torsvik ◽  
Ingunn H. Thorseth ◽  
Frida L. Daae ◽  
...  
Keyword(s):  
The Arctic ◽  
Rrna Gene ◽  
Organic Substrates ◽  
Mid Ocean Ridge ◽  
The Family ◽  
Optimum Ph ◽  
Casamino Acids ◽  
Ocean Ridge ◽  
Complex Organic ◽  
Acetate Butyrate

A novel thermophilic member of the family Thermaceae, designated strain 2M70-1T, was isolated from the wall of an active white smoker chimney collected in the Soria Moria vent field at 71 °N in the Norwegian–Greenland Sea. Cells of the strain were Gram-negative, non-motile rods. Growth was observed at 37–75 °C (optimum 65 °C), at pH 6–8 (optimum pH 7.3) and in 1–5 % (w/v) NaCl (optimum 2.5–3.5 %). The isolate was aerobic but could also grow anaerobically using nitrate or elemental sulfur as electron acceptors. The strain was obligately heterotrophic, growing on complex organic substrates like yeast extract, Casamino acids, tryptone and peptone. Pyruvate, acetate, butyrate, sucrose, rhamnose and maltodextrin were used as complementary substrates. The G+C content of the genomic DNA was 68 mol%. Cells possessed characteristic phospholipids and glycolipids. Major fatty acids constituted saturated and unsaturated iso-branched and saturated anteiso-branched forms. Menaquinone 8 was the sole respiratory lipoquinone. Phylogenetic analysis of 16S rRNA gene sequences placed the strain in the family Thermaceae in the phylum ‘Deinococcus–Thermus’, which is consistent with the chemotaxonomic data. On the basis of phenotypic and phylogenetic data, strain 2M70-1T ( = JCM 15963T  = DSM 22268T) represents the type strain of a novel species of a novel genus, for which the name Rhabdothermus arcticus gen. nov., sp. nov. is proposed.

scholarly journals The effects of offshore petroleum exploitation on microbial community and antibiotic resistome of adjacent marine sediments

2020 ◽  
Vol 81 (12) ◽  
pp. 2501-2510
Author(s):  
Jing Wang ◽  
Jiti Zhou
Keyword(s):  
Antibiotic Resistance ◽  
Microbial Community ◽  
Marine Sediments ◽  
Microbial Community Composition ◽  
Antibiotic Resistance Genes ◽  
Multidrug Transporter ◽  
Class I Integrons ◽  
Abundance And Diversity ◽  
The Impact ◽  
Offshore Petroleum

Abstract The exploitation of petroleum in offshore areas is becoming more prosperous due to the increasing human demand for oil. However, the effects of offshore petroleum exploitation on the microbial community in the surrounding environment are still not adequately understood. In the present study, variations in the composition, function, and antibiotic resistance of the microbial community in marine sediments adjacent to an offshore petroleum exploitation platform were analyzed by a metagenomics-based method. Significant shifts in the microbial community composition were observed in sediments impacted by offshore petroleum exploitation. Nitrosopumilales was enriched in marine sediments with the activities of offshore petroleum exploitation compared to the control sediments. The abundances of function genes involved in carbon, butanoate, methane, and fatty acid metabolism in sediment microbial communities also increased due to the offshore petroleum exploitation. Offshore petroleum exploitation resulted in the propagation of some antibiotic resistance genes (ARGs), including a multidrug transporter, smeE, and arnA, in marine sediments via horizontal gene transfer mediated by class I integrons. However, the total abundance and diversity of ARGs in marine sediments were not significantly affected by offshore petroleum exploitation. This study is the first attempt to analyze the impact of offshore petroleum exploitation on the spread of antibiotic resistance.

scholarly journals Benthic Communities on the Mohn’s Treasure Mound: Implications for Management of Seabed Mining in the Arctic Mid-Ocean Ridge

2020 ◽  
Vol 7 ◽  
Author(s):  
Eva Ramirez-Llodra ◽  
Ana Hilario ◽  
Emil Paulsen ◽  
Carolina Ventura Costa ◽  
Torkild Bakken ◽  
...  
Keyword(s):  
Benthic Communities ◽  
The Arctic ◽  
Mid Ocean Ridge ◽  
Ocean Ridge ◽  
Seabed Mining

scholarly journals Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 482 ◽  
Author(s):  
Przemyslaw Kowalczuk ◽  
Hassan Bouzahzah ◽  
Rolf Kleiv ◽  
Kurt Aasly
Keyword(s):  
Industrial Applications ◽  
The Arctic ◽  
Central Pacific ◽  
Massive Sulfides ◽  
Central Pacific Ocean ◽  
Polymetallic Nodules ◽  
Mid Ocean Ridge ◽  
Different Types ◽  
Loki’S Castle ◽  
Ocean Ridge

Simultaneous leaching of seafloor massive sulfides (SMS) from Loki’s Castle on the Arctic Mid-Ocean Ridge (AMOR) and polymetallic nodules (PN) from Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean was studied. Leaching tests were conducted using sulfuric acid and sodium chloride, at a temperature of 80 °C for 48 h under reflux. The effect of PN-to-SMS ratio was examined. It was shown that simultaneous leaching of two different types of marine resources was possible resulting in high dissolution rates of metals. The proposed process has many advantages as it does not require pyrometallurgical pretreatment, and yields solid products (i.e., silica, barite, elemental sulfur, albite, microcline, muscovite), which might be utilized for various industrial applications.

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