Temporal Variations of a Natural Hydrocarbon Seep Using a Deep-Sea Camera System

2020 ◽  
Vol 37 (9) ◽  
pp. 1737-1751
Author(s):  
Mahdi Razaz ◽  
Daniela Di Iorio ◽  
Binbin Wang ◽  
Ian MacDonald
Keyword(s):  
Discharge Rate ◽  
Cross Flow ◽  
Time Lapse ◽  
Temporal Variations ◽  
Rise Velocity ◽  
Hydrocarbon Seep ◽  
Camera System ◽  
Temporal And Spatial Variability ◽  
Bubble Characteristics ◽  
Natural Hydrocarbon

AbstractTwo video time-lapse cameras (VTLCs) were deployed by a remotely operated underwater vehicle (ROV) to observe the temporal and spatial variability of a natural hydrocarbon seep at 1180 m depth in the Green Canyon 600 lease block, Gulf of Mexico. The VTLCs were positioned approximately 60 and 90 cm away from the vent, each recording 15 s video bursts at 30 frames per second, illuminated by a 2000 lumen (lm) LED lamp. One camera functioned for 2 weeks; the second camera recorded 568 video bursts at 6 h intervals from 3 September 2017 to 2 February 2018 (153 days). Over the campaign period, seepage from three vents along a 10 cm cluster shifted toward a new fault line with up to nine intermittent individual vents shifting along 20 cm. We developed a semisupervised algorithm using Mathematica and ImageJ routines to resolve the rise velocity and size of individual bubbles. The algorithm was applied to the last 30 frames of each video burst. Bubble characteristics were also analyzed in the videos recorded by the ROV camera. Processing VTLC records yielded a bubble size distribution comparable (5% deviation) to the ROV camera, while the rise velocities were found to be 12% smaller than the ROV data. Hydrocarbon flux estimated from VTLC data was also compared favorably (2% difference) with synoptic physical collections of hydrocarbons into an ROV-held funnel. The long-term measurements indicate that bubble rise velocity was weakly correlated to the discharge rate as well as to the cross-flow velocity.

Seasonal deposition of phytodetritus to the deep-sea floor

1986 ◽  
Vol 88 ◽  
pp. 265-279 ◽  
Author(s):  
A. L. Rice ◽  
D. S. M. Billett ◽  
J. Fry ◽  
A. W. G. John ◽  
R. S. Lampitt ◽  
...  
Keyword(s):  
Deep Sea ◽  
Benthic Communities ◽  
Time Lapse ◽  
Sediment Traps ◽  
Temporal Variations ◽  
Sea Floor ◽  
Porcupine Seabight ◽  
The Past ◽  
Sea Bed ◽  
Seasonal Deposition

SynopsisEvidence has accumulated over the past twenty years to suggest that the deep-sea environment is not as constant as was at one time thought, but exhibits temporal variations related to the seasonally in the overlying surface waters. Recent results from deep-moored sediment traps suggest that this coupling is mediated through the sedimentation of organic material, while observations in the Porcupine Seabight indicate that in this region, at least, there is a major and rapid seasonal deposition of aggregated phytodetritus to the sea-floor at slope and abyssal depths.This paper summarises the results of the Porcupine Seabight studies over the past five years or so, using time-lapse sea-bed photography and microscopic, microbiological and chemical analyses of samples of phytodetritus and of the underlying sediment. The data are to some extent equivocal, but they suggest that the seasonal deposition is a regular and dramatic phenomenon and that the material undergoes relatively little degradation during its passage through the water column. The mechanisms leading to the aggregation of the phytodetritus have not been identified, and it is not yet known whether the phenomenon is geographically widespread nor whether it is of significance to the deep-living mid-water and benthic communities.

scholarly journals Potentials and pitfalls of permafrost active layer monitoring using the HVSR method: A case study in Svalbard

2018 ◽  
Author(s):  
Andreas Köhler ◽  
Christian Weidle
Keyword(s):  
Active Layer ◽  
Spectral Ratio ◽  
Time Lapse ◽  
Careful Analysis ◽  
Temporal Variations ◽  
Soil Conditions ◽  
Seismic Velocities ◽  
Essential Information ◽  
Hvsr Method ◽  
Changing Noise

Abstract. Time-lapse monitoring of the sub-surface using ambient seismic noise is a popular method in environmental seismology. We assess the reliability of the Horizontal-to-Vertical Spectral Ratio (HVSR) method for monitoring seasonal permafrost active layer variability in northwest Svalbard. We observe complex HVSR variability between 1 and 50 Hz in the record of a temporary seismic deployment covering frozen and thawn soil conditions between April and August 2016. While strong variations are due to changing noise conditions, mainly affected by wind speed and degrading coupling of instruments during melt season, a seasonal trend is observed at some stations that has most likely a sub-surface structural cause. A HVSR peak emerges close to the Nyquist frequency (50 Hz) in beginning of June which is then gradually gliding down, reaching frequencies of about 15–25 Hz in the end of August. This observation is consistent with HVSR forward-modeling for a set of structural models that simulate different stages of active layer thawing. Our results reveal a number of potential pitfalls when interpreting HVSRs and suggest a careful analysis of temporal variations since HVSR seasonality is not necessarily related to changes in the sub-surface. We compile a list of recommendations for future experiments, including comments on network layouts suitable for array beamforming and waveform correlation methods that can provide essential information on noise source variability. In addition, we investigate if effects of changing noise sources on HVSRs can be avoided by utilizing a directional, narrow-band (4.5 Hz) repeating seismic tremor which is observed at the permanent seismic broadband station KBS in the study area. A significant change of the radial component HVSR shape during summer months is observed for all tremors. We show that a thawn active layer with very low seismic velocities would affect Rayleigh wave ellipticities in the tremor frequency band.

scholarly journals Variability of a natural hydrocarbon seep and its connection to the ocean surface

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mahdi Razaz ◽  
Daniela Di Iorio ◽  
Binbin Wang ◽  
Samira Daneshgar Asl ◽  
Andreas M. Thurnherr
Keyword(s):  
Ocean Surface ◽  
Hydrocarbon Seep ◽  
Natural Hydrocarbon

Measurement of seawater average velocity using water bottom multiples from vertical seismic profile surveys

2016 ◽  
Vol 4 (4) ◽  
pp. SQ13-SQ22 ◽  
Author(s):  
Yingping Li ◽  
Ben Hewett
Keyword(s):  
Average Velocity ◽  
Seismic Velocity ◽  
Autonomous Underwater Vehicles ◽  
Time Lapse ◽  
Seismic Profile ◽  
Temporal Variations ◽  
Vertical Seismic Profile ◽  
Velocity Models ◽  
Vsp Data ◽  
Water Bottom

Previous diagnoses of surface seismic velocity models with vertical seismic profile (VSP) data in the Gulf of Mexico have indicated that shallow velocities were poorly constrained by VSP due to ringing caused by multiple casing strings. This ringing also hampered direct measurement of the seawater average velocity (SWAV) at a rig site with direct arrivals of a zero-offset VSP (ZVSP). We have directly measured the SWAV at a rig site with a known water depth by using differential times between primary water bottom multiples (WBMs) and direct first arrivals acquired in a marine VSP survey. We developed a procedure to process ZVSP-WBM signals for SWAV measurement. This WBM method is successfully applied to VSP data recorded at 27 rig sites in the deep-water environments of North and South America. Our results suggest that VSP processors should implement this method and add the SWAV measurement in their future velocity survey reports. We have estimated water bottom depths using differential times. We found that the estimated water depths are comparable with those acquired from sonar measurements by autonomous underwater vehicles, but with large uncertainties. The WBM method is extended by using data from a vertical incidence VSP to measure a profile of the SWAV along the path of a deviated well and evaluate possible lateral variations of SWAV. This method can potentially be applied to a time-lapse VSP to monitor temporal variations of SWAV. We also evaluated the application scope and limitations of the WBM method.

scholarly journals Eulerian Video Magnification for Cleaning and Inspection of Air Conditioning Ducts With Rover Robot

2020 ◽  
Vol 8 (3) ◽  
pp. 38-47 ◽  
Author(s):  
Filipe dos Santos Aureliano ◽  
Alessandro Ferreira Alves ◽  
Rodrigo Franklin Frogeri ◽  
Wanderson Gomes de Souza ◽  
Simone de Paula Teodoro Moreira ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Temporal Variations ◽  
Camera System ◽  
Naked Eye ◽  
The World ◽  
Removal Of Impurities ◽  
The Many ◽  
Air Conditioning Systems ◽  
Industrial Context

This paper presents a diversied artifice of a Rover robot prototype in order to inspect abnormalities in air conditioning ducts and ventilation through an integrated rotating high-resolution camera system Eulerian Video Magnification is a  method capable of revealing temporal  variations of a body in videos that are impossible to see with the naked eye. Using this method, it is possible to visualize the flow of microorganisms present in the ducts, in which the images are R.W. transmitted in real time to the operator, allowing the cleaning with rotating brushes that adapt themselves  according to the  pipeline geometry, linked to the rover making the removal of impurities which are found on the walls, as well as the application of fungicides and bactericides, and finally the mechanism structure allows the manipulation of small objects held by a claw, which ensures greater operating flexibility compared to existing systems on the market. Due to weather problems being the main responsible for the considerable rise in temperature around the world, this has led man to seek ways by which people have comfort in both residential and industrial context. The most widely used alternative to soften or even solve this problem indoors has been the use of air conditioning systems. Despite the many advantages that these systems provide, there is great concern with the quality of air being supplied to the user according to the procedures and requirements of NBR 15848: 2010.

scholarly journals Microfluidic monitoring of the growth of individual hyphae in confined environments

2020 ◽  
Vol 7 (8) ◽  
pp. 191535
Author(s):  
Claire Baranger ◽  
Antoine Fayeulle ◽  
Anne Le Goff
Keyword(s):  
Growth Velocity ◽  
Fungal Growth ◽  
Time Lapse ◽  
Temporal Variations ◽  
Culture Conditions ◽  
Soil Bioremediation ◽  
Soil Matrix ◽  
Key Factor ◽  
Fine Control ◽  
Parallel Microchannels

Soil fungi have the ability to form large mycelial networks. They rely on the resources available in the soil to produce biomass and are able to degrade complex biomolecules. Some of them can even degrade recalcitrant organic pollutants and are considered as promising candidates for soil bioremediation strategies. However, the success of this approach depends on the ability of fungi to colonize the soil matrix, where they encounter spatial and temporal variations of confinement, humidity and nutrient concentration. In this paper, we present a study of fungal growth at the scale of single hyphae in a microfluidic device, allowing fine control of nutrient and water supply. Time-lapse microscopy allowed simultaneous monitoring of the growth of dozens of hyphae of Talaromyces helicus , a soil isolate, and of the model fungus Neurospora crassa through parallel microchannels. The distributions of growth velocity obtained for each strain were compared with measurements obtained in macroscopic solid culture. For the two strains used in the study, confinement caused the growth velocity to drop in comparison with unconfined experiments. In addition, N. crassa was also limited in its growth by the nutrient supply, while the microfluidic culture conditions seemed better suited for T. helicus . Qualitative observations of fungi growing in microfluidic chambers without lateral confinement also revealed that side walls influence the branching behaviour of hyphae. This study is one of the first to consider the confinement degree within soil microporosities as a key factor of fungal growth, and to address its effect, along with physicochemical parameters, on soil colonization, notably for bioremediation purposes.

Hydrodynamic Characteristics of Mixing in a Non-Newtonian Liquid-Gas-Solid System

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Thamer Mohammed Jassim ◽  
Abbas Hamid Sulaymon ◽  
Asawer Abdul Raswel Al-Wasiti
Keyword(s):  
Apparent Viscosity ◽  
Mixing Time ◽  
Bubble Diameter ◽  
Particle Diameter ◽  
Solid Loading ◽  
Rise Velocity ◽  
Gas Velocity ◽  
Bubble Rise Velocity ◽  
Three Phase ◽  
Bubble Characteristics

This work presents the study of mixing a three phase non-Newtonian system in a QVF gas sparged vessel. The three phase system consists of air-non Newtonian liquid (polyacrylamide solution)–solid (alumina catalyst). The critical gas velocity for complete suspension of solid particles, mixing time, and bubble characteristics (bubble rise velocity, bubble diameter, bubble frequency, gas hold up, and number of bubbles) was studied with different polyacrylamid (PAA) concentrations (0.01, 0.03,0.05, 0.07) wt%, different particle diameters of alumina (63-500)µm, and different solid loading of alumina (0.5, 1.0, 1.5, 2.0)Kg. The critical gas velocity was found to increase with increasing apparent viscosity, solid loading, and particle diameter. Mixing time increases with increasing apparent viscosity, and decreases with increasing solid loading, and particle diameter. Bubble characteristics were measured axially and radially using a modified electroconductivity probe consisting of four tips, an interface, a visual basic program, and a personal computer. The results showed that increasing apparent viscosity and particle diameter caused an increase of bubble coalescence and hence, an increase in bubble diameter and bubble rise velocity and a decrease in gas hold up.

Submersible Hawaiian Aquatic Research Camera System: STEM Initiatives Fostering the Study of Hawaii's Marine Biota Using Underwater Time-Lapse Photography

2015 ◽  
Vol 49 (4) ◽  
pp. 119-125
Author(s):  
Christopher James Lindsay ◽  
Rafael Silk Lee ◽  
Mark D. Lindsay ◽  
Margo H. Edwards ◽  
Mark R. Rognstad ◽  
...  
Keyword(s):  
High School ◽  
High School Students ◽  
Time Lapse ◽  
Raspberry Pi ◽  
Marine Biota ◽  
School Students ◽  
Marine Animals ◽  
Engineering Project ◽  
Camera System ◽  
Time Lapse Photography

AbstractIn contrast to the traditional mentor-apprentice relationship inherent in most high school science research projects, a team of high school students designed and executed their own research study that focused on engineering a low-cost (<$1,000) camera and light apparatus to perform underwater time-lapse photography. With the advice of mentors from the University of Hawaii, the STEM community, and 'Iolani School, the team used their apparatus to study biota living underwater in caves near Makai Research Pier offshore of East Oahu, Hawaii. The photographic system consisted of a Raspberry Pi microcomputer and camera board synchronized with a homemade LED lighting system housed in aluminum or PVC piping with acrylic windows. Several deployments in shallow water (<5 m) yielded images of Hawaiian Whitetip Reef shark (Triaenodon obesus), Hawaiian Green Sea turtles (Chelonia mydas), and other marine animals in their natural reef habitat. The project demonstrates that, in less than a year, high school students can overcome the challenges of building an inexpensive, underwater time-lapse camera system to study the behavior of marine biota. This article describes the team's engineering project, scientific research, lessons learned, and outreach efforts in the hope that other educational, scientific, and governmental institutions will be encouraged to offer similar, enriching opportunities to nurture high school students to conduct STEM studies that advance ongoing, related research.

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