Ocean Bottom Sediments Research Articles

УЧЕНИЕ АКАДЕМИКА А.П. ЛИСИЦЫНА О ГЛОБАЛЬНЫХ БИОЛОГИЧЕСКИХ ФИЛЬТРАХ И РАЗВИТИЕ БИОГЕОХИМИИ МИКРОЭЛЕМЕНТОВ В ОКЕАНЕ

Academician Alexander P. Lisitsyn has developed a theory of biogenic sedimentation and global biofilters in the ocean that became an important part of marine geology and geochemistry. As a follower of Academician V.I. Vernadsky, A.P. Lisitsyn revealed a fundamental role of living matter in formation of the major part of the ocean bottom sediments. This paper presents some data on the trace metal biogeochemistry in the ocean, their bioaccumulation in the global ocean biofilters is quantitively evaluated.

УЧЕНИЕ АКАДЕМИКА А.П. ЛИСИЦЫНА О ГЛОБАЛЬНЫХ БИОЛОГИЧЕСКИХ ФИЛЬТРАХ И РАЗВИТИЕ БИОГЕОХИМИИ МИКРОЭЛЕМЕНТОВ В ОКЕАНЕ

Academician A.lexander P. Lisitsyn has developed a theory of biogenic sedimentation and global biofilters in the ocean that became an important part of marine geology and geochemistry. As a follower of Academician V.I. Vernadsky, A.P. Lisitsyn revealed a fundamental role of living matter in formation of the major part of the ocean bottom sediments. This paper presents some data on the trace metal biogeochemistry in the ocean, their bioaccumulation in the global ocean biofilters is quantitively evaluated.

Potential Future Alternative Resources for Rare Earth Elements: Opportunities and Challenges

Currently, there is an increasing industrial demand for rare earth elements (REE) as these elements are now integral to the manufacture of many carbon-neutral technologies. The depleting REE ores and increasing mining costs are prompting us to consider alternative sources for these valuable metals, particularly from waste streams. Although REE concentrations in most of the alternative resources are lower than current REE ores, some sources including marine sediments, coal ash, and industrial wastes, such as red mud, are emerging as promising with significant concentrations of REE. This review focuses on the alternative resources for REE, such as ocean bottom sediments, continental shelf sediments, river sediments, stream sediments, lake sediments, phosphorite deposits, industrial waste products, such as red mud and phosphogypsum, coal, coal fly ash and related materials, waste rock sources from old and closed mines, acid mine drainage, and recycling of e-waste. Possible future Moon exploration and mining for REE and other valuable minerals are also discussed. It is evident that REE extractions from both primary and secondary ores alone are not adequate to meet the current demand, and sustainable REE recovery from the alternative resources described here is also necessary to meet the growing REE demand. An attempt is made to identify the potential of these alternative resources and sustainability challenges, benefits, and possible environmental hazards to meet the growing challenges of reaching the future REE requirements.

Rare Earth Element Deposits: Sources, and Exploration Strategies

Abstract Rare earth elements (REE) include the lanthanide series (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) plus Sc and Y. All these metals occur together in different types of REE deposits such as carbonatites, alkali syenites and monazite-rich placers, and are found in more than 250 minerals in the Earth’s crust. The future of the world’s green technologies depends upon their availability and supply. At present, China is responsible for 80% of global REE production. However, countries such as USA, Australia, India, and Kazakhstan also extract and refine significant quantities of REE. These metals occur in primary deposits associated with igneous and hydrothermal processes, and secondary deposits concentrated by sedimentary processes and weathering. However, other types of resources such as ocean bottom sediments, waste rocks in closed mines, river sediments, industrial wastes like red mud, coal, and fly ash have proved to be containing significant amounts of these elements. Besides the beach sand deposits, the Amba Dongar carbonatite complex, and carbonatite plugs hosting REE deposits at Kamthai have been recognized as a potential REE resource in India. Significant concentrations of REE were identified in the deep-sea sediments of Afanasy Niktin Seamount in the Indian Ocean. Integrated exploration methods are playing a key role in the search for new REE mineral deposits. During geochemical exploration studies, portable analytical instruments such as pXRF, pLIBS, portable Raman spectrometer, and a couple of nuclear techniques have enabled successful results in recent times both on and off the land at lower costs, and allowing rapid decision-making on exploration strategies directly in the field.

An overview of seabed characterization experiment

An overview of the Spring 2021 component of the Seabed Characterization Experiment will be presented. The project is focused on the acoustics of fine-grained ocean bottom sediments. The study site is the New England Shelf, south of Martha’s Vineyard, MA, USA. The goals of the project are (1) understand the physical mechanisms that control acoustic propagation in fine-grained sediments, (2) quantify uncertainties in the estimation of seabed parameters, (3) correlate the observed horizontal variations in the acoustical field with the measured horizontal variability of the seabed and (4) assess the performance of the resulting geoacoustic models, and inversion and statistical inference methods. These goals have been pursued by obtaining direct measurements and/or inferring the values of the following parameters over a wide frequency band: compressional wave speed and attenuation, shear wave speed and attenuation, and seabed layering and gradients. Oceanographic data were collected to support both forward and inverse modeling efforts. A major part of this effort was completed in 2017 and a follow-on effort is planned for 2021 and 2022. This presentation provides an overview of the project, a summary of past results, and a discussion of the most recent work. [Work supported by ONR.]

Local Neighbourhood Edge Responsive Image Descriptor for Texture Classification Using Gaussian Mutated JAYA Optimization Algorithm

Local feature descriptor plays a significant role in texture classification. However, in the traditional local binary pattern method, image pixels are converted into a binary pattern based on the relationship between center and neighborhood pixels. This paper introduces a novel feature extraction method named local neighbourhood edge responsive binary pattern to extract and categorize reliable texture features from images for achieving an automated classification of different types of ocean bottom sediments. Initially, the basic magnitude variance pixel values are derived depending on an odd and even pixel value of a 3 × 3 image patch. Further, the edge information is extracted using the local directional pattern method from all images. The edge response of the image is obtained using a kirsch mask in all eight directions. The encoding condition is then applied to both the local intensity and the edge information to create a unique descriptor value. Finally, a new learning algorithm called GMJAYA-ELM combines the Gaussian mutated JAYA (GMJAYA) with an extreme learning machine (ELM) for texture classification. The GMJAYA is used to optimize the input weights and hidden biases of single-hidden-layer feed-forward neural networks. Experimental findings indicate that the suggested method yields better accuracy and sensitivity efficiency among various groups. The proposed algorithm is tested by contrasting outcomes with standard learning schemes such as PSO-ELM, GA-ELM, ABC-ELM, Birdswarm-ELM, and JAYA-ELM, suggesting the dominance of GMJAYA-ELM.

Ocean surface and bottom water conditions, iceberg drift and sediment transport on the North Iceland margin during MIS 3 and MIS 2

Radiocarbon dates and marine tephra suggest that the upper 10 m of core MD99-2274 off North Iceland extends from ∼0 to ∼65 ka BP. A multi-proxy sediment and biomarker study at a ∼0.5 ky resolution is used to derive a paleoclimate scenario for this area of the southwestern Nordic Seas, which during the Holocene had intermittent excursions of icebergs and a seasonal cover of drifting sea ice across the site. The sortable silt mean size (S̅S̅) suggests a bottom current (1000 m depth) flow speed maximum to minimum range of ∼8 cm/s during Marine Isotope Stages 2–3, but the data are unreliable for the Holocene. Slow-down in flow speeds may be associated with massive ice and water discharges linked to the Hudson Strait ice stream (H-events) and to melt of icebergs from Greenland in the Nordic seas where convection would have been suppressed. Five pulses of sediment with a distinct felsic component are associated with iceberg transport from E/NE Greenland. Sea ice, open water and sea surface temperature (SST) biomarker proxies (i.e. IP25, HBI III, brassicasterol and alkenones) all point towards near-perennial sea ice cover during MIS 3 and 2, rather than seasonal sea ice or open water conditions. Indeed, our biomarker and sediment data require that the seas north of Iceland experienced a nearly continuous cover of sea ice, together with icebergs calved from ice stream termini, which drifted southward. The cross-correlation of the quartz % records between MD99-2274 and the well-dated core PS2644 in Blosseville Basin indicates significant coherence in the records at a multi-millennial (∼8 ky) timescale. A transition to open ocean conditions is evident from the early Holocene onwards, albeit with the occurrence of some drift ice and icebergs.

Matched-field geoacoustic inversion using propagation invariant in a range-dependent waveguide.

Although matched-field geoacoustic inversion (MFI) has been successfully applied for seabed sediment parameters, its estimation capabilities are limited due to the range dependence of ocean sound-speed profiles, bathymetry, and bottom sediment. This paper proposes a method called propagation invariant (PI). As a purely data-driven method, PI eliminates the effect of intervening range-dependent variations on acoustic propagation and depends only on the "local" environmental characteristics, thus providing ideal input data for MFI. In this paper, the PI concept is applied for MFI in a range-dependent environment by simulations. Results show good MFI performance even for a highly range-dependent waveguide.

Plastic world

Plastic world

Rethinking the Use of Seabed Sediment Temperature Profiles to Trace Submarine Groundwater Flow

AbstractSubmarine groundwater fluxes across the seafloor facilitate important hydrological and biogeochemical exchanges between oceans and seabed sediment, yet few studies have investigated spatially distributed groundwater fluxes in deep‐ocean environments such as continental slopes. Heat has been previously applied as a submarine groundwater tracer using an analytical solution to a heat flow equation assuming steady state conditions and homogeneous thermal conductivity. These assumptions are often violated in shallow seabeds due to ocean bottom temperature changes or sediment property variations. Here heat tracing analysis techniques recently developed for terrestrial settings are applied in concert to examine the influences of groundwater flow, ocean temperature changes, and seabed thermal conductivity variations on deep‐ocean sediment temperature profiles. Temperature observations from the sediment and bottom ocean water on the Scotian Slope off eastern Canada are used to demonstrate how simple thermal methods for tracing groundwater can be employed if more comprehensive techniques indicate that the simplifying assumptions are valid. The spatial distribution of the inferred groundwater fluxes on the slope suggests a downward groundwater flow system with recharge occurring over the upper‐middle slope and discharge on the lower slope. We speculate that the downward groundwater flow inferred on the Scotian Slope is due to density‐driven processes arising from underlying salt domes, in contrast with upward slope systems driven by geothermal convection. Improvements in the design of future submarine hydrogeological studies are proposed for thermal data collection and groundwater flow analysis, including new equations that quantify the minimum detectable flux magnitude for a given sensor accuracy and profile length.

A case study for late Archean and Proterozoic biogeochemical iron- and sulphur cycling in a modern habitat-the Arvadi Spring.

As a consequence of Earth's surface oxygenation, ocean geochemistry changed from ferruginous (iron(II)-rich) into more complex ferro-euxinic (iron(II)-sulphide-rich) conditions during the Paleoproterozoic. This transition must have had profound implications for the Proterozoic microbial community that existed within the ocean water and bottom sediment; in particular, iron-oxidizing bacteria likely had to compete with emerging sulphur-metabolizers. However, the nature of their coexistence and interaction remains speculative. Here, we present geochemical and microbiological data from the Arvadi Spring in the eastern Swiss Alps, a modern model habitat for ferro-euxinic transition zones in late Archean and Proterozoic oceans during high-oxygen intervals, which enables us to reconstruct the microbial community structure in respective settings for this geological era. The spring water is oxygen-saturated but still contains relatively elevated concentrations of dissolved iron(II) (17.2±2.8μM) and sulphide (2.5±0.2μM) with simultaneously high concentrations of sulphate (8.3±0.04mM). Solids consisting of quartz, calcite, dolomite and iron(III) oxyhydroxide minerals as well as sulphur-containing particles, presumably elemental S0 , cover the spring sediment. Cultivation-based most probable number counts revealed microaerophilic iron(II)-oxidizers and sulphide-oxidizers to represent the largest fraction of iron- and sulphur-metabolizers in the spring, coexisting with less abundant iron(III)-reducers, sulphate-reducers and phototrophic and nitrate-reducing iron(II)-oxidizers. 16S rRNA gene 454 pyrosequencing showed sulphide-oxidizing Thiothrix species to be the dominating genus, supporting the results from our cultivation-based assessment. Collectively, our results suggest that anaerobic and microaerophilic iron- and sulphur-metabolizers could have coexisted in oxygenated ferro-sulphidic transition zones of late Archean and Proterozoic oceans, where they would have sustained continuous cycling of iron and sulphur compounds.

Through-the-sensor sediment characterization from autonomous underwater vehicle sonar systems

Ocean bottom sediment type is a key parameter in understanding physical processes such as sediment transport and object burial as well as acoustic processes such as propagation and backscatter. However, direct methods such as coring and grab samples are time-consuming and coverage limited. The analysis of normal-incidence echo sounding has proven to be a reliable technique for certain frequency ranges. For this method, a clear understanding of the physical processes such as scattering and reflection is critical. For higher coverage, the normal-incidence echo sounder technique can be applied to through-the-sensor measurements. This is attractive since it requires no additional equipment particularly important to autonomous underwater vehicle operations. However, through-the-sensor measurements have the additional complications of understanding hardware and signal processing algorithms that were not specifically designed for sediment characterization or normal-incidence echo sounding. In this talk, measurements from two sensors, the light-weight conformal array and the small synthetic aperture minehunter, are analyzed for sediment type. The results are compared with ground truth data. Challenges and issues involved with using these sensors for sediment characterization will be discussed. [Work supported by ONR, Ocean Acoustics.]

Acoustic scattering by tube-building worms (Polychaeta: Maldanidae) of the New England Mud Patch

The acoustic effects of biological activity within shallow water ocean environments are not well understood, yet are of increasing importance in some sonar applications. These environments remain insufficiently characterized in part due to the presence of benthic organisms within and near the sediment and water-sediment interface. Among the most prevalent infauna found within muddy ocean sediments are tube-building worms (Polychaeta: Maldanidae). The presence of and bioturbation caused by these organisms can affect the acoustical properties of the ocean bottom sediment. These effects are being studied in experiments being conducted in the New England Mud Patch, on the continental shelf south of Martha’s Vinyard, MA. To begin to quantify these effects, laboratory acoustic scattering measurements of naturally collected worms and worm tubes were completed over a range of frequencies (50 kHz to 1 MHz) and incidence angles. Predictive models by Faran [J. Acoust. Soc. Am. 23, 405 (1951)] approximating the worms as elastic cylinders, and Doolittle [J. Acoust. Soc. Am. 39, 272 (1966)] approximating the worm tubes as cylindrical shells, were used to interpret the measured results. Measurements and model comparisons will be discussed along with implications relating to effective bulk sediment properties. [Work supported by ONR.]

Preliminary characterization of surficial sediment acoustic properties and infauna in the New England Mud Patch

Biology is prevalent on and within many ocean bottom sediments. Organisms can include animals dwelling at or near the water-sediment interface or infauna living within surficial sediments. Bioturbation from burrowing, tube building, or other activities can have physical effects on the sediment acoustic properties. As part of the Sediment Characterization Experiment, a survey cruise was conducted in August 2015 in the New England Mud Patch, a region in the Atlantic continental shelf characterized by a layer of mud up to 12 m thick overlying a sandy subbottom. In addition to gravity coring operations to determine the properties of the mud layer, box cores and multicores were collected to examine the surficial sediment properties. Infauna were prevalent in the surficial sediment samples and were collected and characterized for body size, hardness, and potential for bioturbation or structuring. Shipboard measurements of shear and compressional waves were performed on the box core samples using time-of-flight measurements. Preliminary results from the infauna analysis and the shipboard acoustic measurements will be presented. [Work supported by ONR.]

Acoustic and sediment data in the southern New England Bight

This study provides a review of the acoustic and ocean bottom sediment data collected during the Shelf Break Primer experiment conducted in 1996. The location of the experiment was in the southern New England Continental Shelf called the “New England Mud Patch.” The mud patch is a 13,000 square kilometer area covered by fine-grained sediment. Previous surveys in this area have estimated the thickness of this fine grained sediment deposit to be as much as 13 m. This layer of sediment rests on a reflector that is geomorphically similar to and continuous with the Holocene transgressive sand sheet, which is exposed on the shelf to the west of this area. This fine-grained sediment layer, which is oriented in an east-west direction seaward of the 55–65 m isobath, contains more than 30% silt and clay. During the Primer experiment, broadband acoustic sources were deployed in the western side of the “mud patch” along and across the continental shelf. The acoustic data collected on a vertical line array will be analyzed. Sediment data from gravity cores from the area will also be presented. [Work sponsored by Office of Naval Research, code 322 OA.]

Experimental design for sediment characterization in the New England Mud Patch

This study focuses on the design of an experiment to estimate the shear wave properties of ocean bottom sediments at a location in the southern New England Continental Shelf called the “New England Mud Patch.” The mud patch is a 13,000 square kilometer area covered by fine-grained sediment. The inversion technique is based on collecting interface wave (Scholte wave) data using geophones on the sea bottom. The data for the inversion consist of Scholte wave phase velocity dispersion calculated from the geophone array data. The present study aims at applying this Scholte wave based shear wave inversion technique to the “mud patch” area. Two different interface wave measurement systems will be presented. Appropriate source to receiver ranges will be explored based on simulations. The engineering challenges associated with deploying the system in a soft seabed will be investigated and design modifications will be investigated. Acoustic and sediment data from the 1996 Shelf Break Primer experiment, which was conducted in the western side of the mud patch, will be reviewed. The simulations will be based on historic sediment and acoustic data. [Work sponsored by Office of Naval Research, code 322 OA.]

Shear wave attenuation estimates from Scholte wave data

Scholte waves are valuable tool for estimating the shear properties of the ocean bottom sediments. Previously estimates of the shear wave speed were obtained using interface wave data from a small scale experiment conducted in very shallow water in coastal Rhode Island. The University of Rhode Island’s shear measurement system consisting of vertical axis and three-axis geophones were used to collect data in 3 m of water. Interface waves were excited by dropping a weight from a research vessel. In this study, we use the geophone data to estimate the depth-averaged shear attenuation using spectral amplitude ratios. The estimated sediment properties will be compared with historic core data from the field test location and other published results for similar type of sediments. The correlation of the shear speed and attenuation to sediment properties such as porosity, grain size and bulk density will be discussed. [Work supported by Office of Naval Research.]

Effect of gas bubble on acoustic characteristic of sediment: taking sediment from East China Sea for example

The effect of gas bubble on acoustic characteristic of sediment is important for ocean science, ocean geology, ocean geophysics, etc. Twenty five samples of ocean bottom sediments are extracted through gravity sampling equipment from the East China Sea and are sealed in PVC pipes for storage in order to study the effect of gas bubble on acoustic characteristic of sediment. In order to obtain the gas content of sediment, in this the paper the Micro-CT scanning technology is introduced into sediment measuring method. The different X ray absorption rates of water, gas and solid particles in sediment samples are obtained through Micro-CT scanning using Siemens Micro-CT scanner. The gas volume content and water volume content in sediment can be obtained according to CT number distribution. The acoustic measurement is carried out in laboratory using intelligent nonmetal ultrasonic detector and the 40 kHz waves are launched from one side of the sediment sample and obtained from another side. The acoustic attenuation can be obtained according to the amplitudes of launched and received waves and the acoustic velocity can be obtained according to travelling time when acoustic wave goes through the sediment. The attenuation of sediment sample is about a few to twenty and the velocity is about 1100 to 1700 m-1. By mean of analysis of regression, the correlations are obtained among gas content, fluid content, acoustic velocity, attenuation and power function, which better match the measuring data. The result of study indicates that slight augment of gas content can cause sharp decrease of acoustic velocity and rapid increase of acoustic attenuation. The increment and decrement decrease obviously when the gas content exceeds 10%. The result in this paper is useful to explore oil and gas seismic.

東京の土木における最新の技術動向

Land reclamation undertaken continuously in Tokyo Bay since the Edo era can be regarded as important for advancing civil engineering projects in Tokyo. Haneda airport D-runway extension work (hereafter D-runway construction) was completed in October 2010, with a new 2,500 m runway, operating a 24-h service, built in a sea area having a water depth of 15-20 m. Part of the island airport was constructed with a pier structure to provide flood control for the Tama River and preserve the environment. This report summarizes the marine geological survey, environmental assessment, and groundwater management for D-runway construction on the basis of previous reports. The main characteristics of construction are: marine drilling was carried out about every 500m in the sea area for the marine geological survey; the effects of construction on ocean currents, bottom sediments, and submarine topography were considered in the environment impact assessment of land reclamation; and, a new underground station was constructed with groundwater control provided by a deep-well dewatering system without building a sealing body for groundwater.

Seismo-acoustic propagation near thin and low-shear speed ocean bottom sediments using a massive elastic interface

The seafloor is considered to be a thin surface layer overlying an elastic half space. In addition to layers of this type being thin, they may also have shear wave speeds that can be small (order 100 m/s). Both the thin and low-shear properties, viewed as small parameters, can cause mathematical and numerical singularities to arise. Following the derivation presented by Gilbert [Geophys. J. Int. 133, 230-232 (1998)], the surface layer is approximated as a thick, finite-thickness interface, and modified ocean bottom fluid-solid interface conditions are derived as jump conditions across the interface. The resultant interface conditions are incorporated into a seismo-acoustic parabolic equation solution, and this interface-based solution is benchmarked against existing solutions and previously derived modified fluid-solid interface jump conditions. Accuracy quantification is given via dimensionless interface thickness parameters.