Engineering Properties of Carbonate Marine Sediments

2011 ◽  
Author(s):  
Horst G. Brandes
Keyword(s):  
Water Content ◽  
Marine Sediments ◽  
Relative Abundance ◽  
Deep Sea ◽  
Deep Ocean ◽  
Strength Characteristics ◽  
Engineering Properties ◽  
Carbonate Content ◽  
Frictional Strength

Geotechnical properties of deep-sea sediments are examined in terms of their plasticity, compressibility and frictional strength characteristics, especially in terms of the relative abundance of carbonate and clay fractions. The effect of carbonate content in excess of 40% is to reduce Atterberg limits and compressibility, and to increase peak friction angles, compared to sediments from the deep ocean that have lower carbonate amounts. The presence of carbonate also tends to reduce flocculation and in situ water content.

Permeability of Marine Sediments and Tropical Volcanic Soils

2012 ◽  
Author(s):  
Horst G. Brandes
Keyword(s):  
Grain Size ◽  
Marine Sediments ◽  
Deep Sea ◽  
Carbonate Content ◽  
Clayey Soils ◽  
Index Properties ◽  
Volcanic Soils ◽  
Fine Grained ◽  
Deep Sea Sediments ◽  
Tropical Volcanic Soils

Permeability values for a range of fine-grained deep-sea sediments are presented and evaluated in terms of index properties such as plasticity, grain size and carbonate content. It is found that whereas clay-rich sediments have similar permeabilities to those of equivalent land-based fine-grained soils, the presence of volcanic, carbonate and other non-clay fractions tends to increase permeability somewhat. Volcanic silty-clayey soils from Hawaii have comparable permeability values, although they can be slightly more permeable.

Deep-sea bacteria: growth and utilization of n-hexadecane at in situ temperature and pressure

1975 ◽  
Vol 21 (5) ◽  
pp. 682-687 ◽  
Author(s):  
J. R. Schwarz ◽  
J. D. Walker ◽  
R. R. Colwell
Keyword(s):  
Mixed Culture ◽  
Deep Sea ◽  
Sole Carbon Source ◽  
Ambient Pressure ◽  
Deep Ocean ◽  
Core Sample ◽  
Bacteria Growth ◽  
Deep Sea Bacteria ◽  
Temperature And Pressure

A mixed culture of bacteria was obtained from the sediment-water interface of a core sample taken off the coast of Florida at a depth of 4940 m. The mixed culture was found capable of utilizing n-hexadecane as a sole carbon source for growth at the in situ temperature (4C) and pressure (500 atm). The rate of utilization under deep-ocean conditions was found to be much slower than the rate observed at ambient pressure (1 atm) and low temperature (4C).

scholarly journals Seafloor incubation experiment with deep-sea hydrothermal vent fluid reveals effect of pressure and lag time on autotrophic microbial communities

2021 ◽  
Author(s):  
Caroline S. Fortunato ◽  
David A. Butterfield ◽  
Benjamin Larson ◽  
Noah Lawrence-Slavas ◽  
Christopher K. Algar ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Stable Isotope ◽  
Microbial Communities ◽  
Deep Sea ◽  
Stress Proteins ◽  
Natural Habitat ◽  
Deep Ocean ◽  
Stable Isotope Probing ◽  
Sample Processing

Depressurization and sample processing delays may impact the outcome of shipboard microbial incubations of samples collected from the deep sea. To address this knowledge gap, we developed an ROV-powered incubator instrument to carry out and compare results from in situ and shipboard RNA Stable Isotope Probing (RNA-SIP) experiments to identify the key chemolithoautotrophic microbes and metabolisms in diffuse, low-temperature venting fluids from Axial Seamount. All the incubations showed microbial uptake of labeled bicarbonate primarily by thermophilic autotrophic Epsilonbacteraeota that oxidized hydrogen coupled with nitrate reduction. However, the in situ seafloor incubations showed higher abundances of transcripts annotated for aerobic processes suggesting that oxygen was lost from the hydrothermal fluid samples prior to shipboard analysis. Furthermore, transcripts for thermal stress proteins such as heat shock chaperones and proteases were significantly more abundant in the shipboard incubations suggesting that depressurization induced thermal stress in the metabolically active microbes in these incubations. Together, results indicate that while the autotrophic microbial communities in the shipboard and seafloor experiments behaved similarly, there were distinct differences that provide new insight into the activities of natural microbial assemblages under near-native conditions in the ocean. Importance: Diverse microbial communities drive biogeochemical cycles in Earth’s ocean, yet studying these organisms and processes is often limited by technological capabilities, especially in the deep ocean. In this study, we used a novel marine microbial incubator instrument capable of in situ experimentation to investigate microbial primary producers at deep-sea hydrothermal vents. We carried out identical stable isotope probing experiments coupled to RNA sequencing both on the seafloor and on the ship to examine thermophilic, microbial autotrophs in venting fluids from an active submarine volcano. Our results indicate that microbial communities were significantly impacted by the effects of depressurization and sample processing delay, with shipboard microbial communities more stressed compared to seafloor incubations. Differences in metabolism were also apparent and are likely linked to the chemistry of the fluid at the beginning of the experiment. Microbial experimentation in the natural habitat provides new insights into understanding microbial activities in the ocean.

scholarly journals Biogeochemical Interactions In The Application Of Biotechnological Strategies To Marine Sediments Contaminated With Metals

2015 ◽  
Vol 14 (1) ◽  
pp. 12-31 ◽  
Author(s):  
Viviana Fonti ◽  
Antonio Dell’Anno ◽  
Francesca Beolchini
Keyword(s):  
Marine Sediments ◽  
Environmental Problem ◽  
Sediment Contamination ◽  
Metal Mobility ◽  
Ex Situ ◽  
Carbonate Content ◽  
Anthropogenic Pressure ◽  
Site Specific ◽  
Geochemical Properties

AbstractSediment contamination in coastal areas with high anthropogenic pressure is a widespread environmental problem. Metal contaminants are of particular concern, since they are persistent and cannot be degraded. Microorganisms can influence metal mobility in the sediment by several direct and indirect processes. However, the actual fate of metals in the environment is not easily predictable and several biogeochemical constraints affect their behaviour. In addition, the geochemical characteristics of the sediment play an important role and the general assumptions for soils or freshwater sediments cannot be extended to marine sediments. In this paper we analysed the correlation between metal mobility and main geochemical properties of the sediment. Although the prediction of metal fate in sediment environment, both forex-situbioleaching treatments andin-situbiostimulation strategies, appears to require metal-specific and site-specific tools, we found that TOM and pH are likely the main variables in describing and predicting Zn behaviour. Arsenic solubilisation/increase in mobility appears to correlate positively with carbonate content. Cd, Pb and Ni appear to require multivariate and/or non-linear approaches.

scholarly journals Characterization of the first cultured free-living representative of Candidatus Izimaplasma uncovers its unique biology

2020 ◽  
Author(s):  
Rikuan Zheng ◽  
Rui Liu ◽  
Yeqi Shan ◽  
Ruining Cai ◽  
Ge Liu ◽  
...  
Keyword(s):  
Deep Sea ◽  
Deep Ocean ◽  
Extracellular Dna ◽  
Phenotypic Traits ◽  
The Novel ◽  
Metabolic Potential ◽  
Free Living ◽  
Living Wall ◽  
First Time

AbstractCandidatus Izimaplasma, an intermediate in the reductive evolution from Firmicutes to Mollicutes, was proposed to represent a novel class of free-living wall-less bacteria within the phylum Tenericutes found in deep-sea methane seeps. Unfortunately, the paucity of marine isolates currently available has limited further insights into their physiological and metabolic features as well as ecological roles. Here, we present a detailed description of the phenotypic traits, genomic data and central metabolisms tested in both laboratorial and deep-sea environments of the novel strain zrk13, which allows for the first time the reconstruction of the metabolic potential and lifestyle of a member of the tentatively defined Candidatus Izimaplasma. On the basis of the description of strain zrk13, the novel species and genus Xianfuyuplasma coldseepsis is proposed. Notably, DNA degradation driven by X. coldseepsis zrk13 was detected in both laboratorial and in situ conditions, strongly indicating it is indeed a key DNA degrader. Moreover, the putative genes determining degradation broadly distribute in the genomes of other Izimaplasma members. Given extracellular DNA is a particularly crucial phosphorus as well as nitrogen and carbon source for microorganisms in the seafloor, Izimaplasma bacteria are thought to be important contributors to the biogeochemical cycling in the deep ocean.

Development of a deep-sea mercury sensor using in situ anodic stripping voltammetry

2015 ◽  
Vol 49 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Masahiro Yamamoto ◽  
Hitoshi Kodamatani ◽  
Yuriko Kono ◽  
Akinori Takeuchi ◽  
Ken Takai ◽  
...  
Keyword(s):  
Deep Sea ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Anodic Stripping ◽  
Mercury Sensor
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