Spectroscopy is emerging as a technique that can expand the envelope of modern oceanographic sensors. The selectivity spectroscopic techniques enables single instrument to measure multiple components marine environment and form basis for versatile tools perform in situ geochemical analysis. We have developed deep-sea laser-induced breakdown spectrometer (ChemiCam) successfully deployed from remotely operated vehicle (ROV) multi-element analysis both seawater mineral deposits at depths over...

This paper reviews methods to compensate for matrix effects and self-absorption during quantitative analysis of compositions solids measured using Laser Induced Breakdown Spectroscopy (LIBS) their applications in-situ analysis. Methods reduce on calibration curves are first introduced. The conditions where applicable quantification solid samples limitations discussed. While calibration-free LIBS (CF-LIBS), which corrects theoretically based the Boltzmann distribution law Saha equation, has...

Visual maps of the seafloor can provide objective information to characterize benthic ecosystems and survey distribution mineral deposits on spatial scales that cannot be otherwise assessed. This paper proposes a three‐dimensional mapping method based light sectioning enables simultaneous capture both structure color from images single camera. The advantages include high consistent resolution bathymetry, simplicity setup algorithm used process data it obtains. hardware requirements for...

To inspect the post-accident nuclear core reactor of TEPCO Fukushima Daiichi power plant (F1-NPP), a transportable fiber-coupled laser-induced breakdown spectroscopy (LIBS) instrument has been developed. The developed LIBS was designed to analyze underwater samples in high-radiation field by single-pulse with gas flow or double-pulse breakdown. check feasibility assembled for analysis debris material (mixture fuel core, cladding, construction and so on) F1-NPP, we investigated influence...

We propose a technique of on-site quantitative analysis Zn2+ in aqueous solution based on the combination electrodeposition for preconcentration Zn onto Cu electrode and successive underwater laser-induced breakdown spectroscopy (underwater LIBS) surface under electrochemically controlled potential. Zinc emission lines are observed with present concentration 5 ppm. It is roughly estimated that overall sensitivity over 10 000 times higher achieved by preconcentration. Although LIBS suffers...

Seabed cover of organisms is an established metric for assessing the status many vulnerable marine ecosystems. When deriving estimates from seafloor imagery, a source uncertainty in capturing true distribution introduced by inherent variability and bias annotation method used to extract ecological data. We investigated two common methods estimating organism cover, role size selectivity this variability. Eleven annotators estimated sparse cold-water coral same 96 images with both grid-based...

The influence of laser pulse duration on the spectral emissions observed from bulk ionic solutions has been investigated for hydrostatic pressures between 0.1 and 30 MPa. Transient pressure, shadowgraph imaging spectroscopic measurements were performed single pulses 20 150 ns. transient pressure show that up to MPa, propagation high-pressure shockwave generated by focused causes local reduce below ambient levels during time frame can be made. impulse subsequent reduction in are larger, with...

The effects of pressure on the optical emissions a laser ablated zinc plate immersed in water have been investigated. Well defined emission spectra were observed from plumes generated directly underwater after excitation using single pulse duration <10 ns. It was demonstrated that an increase 0.1 to 30 MPa (300 atm) does not any significant effect intensity, broadness, or fluorescence lifetime spectra. results suggest laser-induced breakdown spectroscopy is, principle, technique suitable for...

The effects of pressure on the emission lines a submerged metallic plate irradiated by long 150 ns duration laser pulse have been investigated. While spectroscopic measurements using multiple-pulse irradiation targets are sensitive to pressure, interactions long-pulse occur during time window where properties dominate transient pressures surrounding ablated region. not external up 30 MPa, and results demonstrate that ablation is available as an analytical technique study solids immersed at...

This paper describes a method to survey the distribution of megabenthos over multi-hectare regions seafloor. Quantitative biomass estimates are made by combining high-resolution 3D image reconstructions, used model spatial relationships between representative taxa, with lower-resolution reconstructions taken wider area in which larger predatory animals can be observed. The is applied region Iheya North field that was target scientific drilling during IODP Expedition 331 2010. An 2.5 ha...

Long-ns-duration, single pulse laser-induced breakdown spectroscopy (LIBS) is known to be an effective method observe well resolved spectra from samples immersed in water at high hydrostatic pressures. The aim of this study investigate whether the signals obtained using are suitable for quantitative analysis chemical composition. Six certified brass alloys consisting copper (Cu), zinc (Zn) and lead (Pb) were measured underwater a laser duration 250 ns, their compositions determined...

This study describes a method to quantify the chemical composition of deep-sea hydrothermal deposits in situ using laser-induced breakdown spectroscopy (LIBS). Partial least squares (PLS) regression analysis is applied spectra obtained long laser pulse with duration 150 ns. The number measurements needed address spatial heterogeneity samples determined through high-resolution mapping elemental distribution rock samples. PLS laboratory measured seawater-submerged achieved an average relative...

A noncontact method to identify sparsely distributed plastic pellets is proposed by integrating holography and Raman spectroscopy in this study. Polystyrene poly(methyl methacrylate) resin with a size of 3 mm located 20 cm water channel were illuminated using collimated continuous wave laser beam diameter 4 wavelength 785 nm. The same was used take holographic image spectrum pellet the shape, size, composition material. Using compact system, morphological chemical analysis large volume...

The "Zero-G" is designated as a new class of underwater robot that capable unrestricted attitude control. A novel control scheme based on internal actuation using moment gyros (CMGs) developed to provide Zero-G autonomous vehicles (AUVs) with this unique freedom in This implemented the CMG-actuated kinematic (IKURA) system was part research. series experiments are performed demonstrate practical application CMGs and verify associated theoretical developments. ability actively stabilize...

An estimated 3.5±0.7×10(15) Bq of (137)Cs is thought to have been discharged into the ocean following melt down at Fukushima Dai-ichi Nuclear Power Plant (F1NPP). While efforts made monitor seafloor radiation levels, sampling techniques used cannot capture continuous distribution radionuclides. In this work, we apply in situ measurement using a towed gamma ray spectrometer map on within 20 km F1NPP. The results reveal existence local anomalies, with levels an order magnitude higher than...

This article describes a multiyear survey of cobalt-rich manganese crust (Mn-crust) deposits using multiple underwater robots.Using two autonomous vehicles and one remotely operated vehicle, mounted with camera systems, multibeam sonar, subbottom sensors, large areas were surveyed by incorporating the advantages each robot to create comprehensive database Mn-crust distribution estimates.The robots clocked in total 438 hours seafloor observation, surveying about 589 km different...

This paper describes acoustic and visual instruments developed to perform high-resolution surveys of the volumetric distribution manganese crusts from an underwater vehicle. The consist device, in situ measurements crust thickness at depths up 3000 m, a vision-based mapping system that generates 3-D color reconstructions seafloor. Methods process information obtained by these sensors automatically identify areas exposed using reconstructions, subsequently determine based on measurements, are...

Abstract Although modern machine learning has the potential to greatly speed up interpretation of imagery, varied nature seabed and limited availability expert annotations form barriers its widespread use in seafloor mapping applications. This motivates research into unsupervised methods that function without large databases human annotations. paper develops an feature method for georeferenced visual imagery considers patterns both within footprint a single image frame broader scale spatial...