scholarly journals At the Interface of Marine Disciplines: Use of Autonomous Seafloor Equipment for Studies of Biofouling Below the Shallow-Water Zone

Oceanography ◽  
2021 ◽  
Vol 34 (3) ◽  
Author(s):  
Alexandra Chava ◽  
◽  
Anna Gebruk ◽  
Glafira Kolbasova ◽  
Artem Krylov ◽  
...  
Keyword(s):  
Cost Effective ◽  
Artificial Substrates ◽  
Ocean Bottom ◽  
Depth Range ◽  
Fouling Community ◽  
Fouling Communities ◽  
Ocean Bottom Seismometers ◽  
Offshore Industry ◽  
One Year ◽  
The Laptev Sea

Biofouling of artificial substrates is a well-known phenomenon that can negatively impact offshore industry operations as well as data collection in the ocean. Fouling communities worldwide have mostly been studied within the top 50 m of the ocean surface, while biofouling below this depth remains largely underreported. Existing methods used to study biofouling are labor intensive and expensive when applied to the deep sea. Here, we propose a simple and cost-effective modification of traditional methods for studying biofouling by mounting test plates on autonomous seafloor equipment and preserving them in ethanol upon retrieval for transport to the laboratory. This method can greatly advance our understanding of biofouling processes in the deeper ocean, including fouling community biodiversity, recruitment, and seasonality. We present two case studies from the Laptev Sea and the Sea of Okhotsk in support of this method. In the first study, we looked at fouling communities on the surfaces of ocean-bottom seismometers deployed for one year in the 36–350 m depth range. In the second study, we tested metal and plexiglass (poly(methyl methacrylate) plates mounted on autonomous bottom stations and found evidence of both micro- and macrofouling after three months of deployment. Our results demonstrate that various autonomous seafloor equipment can be used as supporting platforms for biofouling studies.

scholarly journals Tomography of crust and lithosphere in the western Indian Ocean from noise cross-correlations of land and ocean bottom seismometers

2019 ◽  
Vol 219 (2) ◽  
pp. 924-944 ◽  
Author(s):  
Sarah Hable ◽  
Karin Sigloch ◽  
Eléonore Stutzmann ◽  
Sergey Kiselev ◽  
Guilhem Barruol
Keyword(s):  
Indian Ocean ◽  
Group Velocity ◽  
Western Indian Ocean ◽  
Spreading Ridge ◽  
Ocean Bottom ◽  
Depth Range ◽  
La Réunion ◽  
Velocity Measurements ◽  
Ocean Bottom Seismometers ◽  
Cross Correlations

SUMMARY We use seismic noise cross-correlations to obtain a 3-D tomography model of SV-wave velocities beneath the western Indian Ocean, in the depth range of the oceanic crust and uppermost mantle. The study area covers 2000 × 2000 km2 between Madagascar and the three spreading ridges of the Indian Ocean, centred on the volcanic hotspot of La Réunion. We use seismograms from 38 ocean bottom seismometers (OBSs) deployed by the RHUM-RUM project and 10 island stations on La Réunion, Madagascar, Mauritius, Rodrigues, and Tromelin. Phase cross-correlations are calculated for 1119 OBS-to-OBS, land-to-OBS, and land-to-land station pairs, and a phase-weighted stacking algorithm yields robust group velocity measurements in the period range of 3–50 s. We demonstrate that OBS correlations across large interstation distances of >2000 km are of sufficiently high quality for large-scale tomography of ocean basins. Many OBSs yielded similarly good group velocity measurements as land stations. Besides Rayleigh waves, the noise correlations contain a low-velocity wave type propagating at 0.8–1.5 km s−1 over distances exceeding 1000 km, presumably Scholte waves travelling through seafloor sediments. The 100 highest-quality group velocity curves are selected for tomographic inversion at crustal and lithospheric depths. The inversion is executed jointly with a data set of longer-period, Rayleigh-wave phase and group velocity measurements from earthquakes, which had previously yielded a 3-D model of Indian Ocean lithosphere and asthenosphere. Robust resolution tests and plausible structural findings in the upper 30 km validate the use of noise-derived OBS correlations for adding crustal structure to earthquake-derived tomography of the oceanic mantle. Relative to crustal reference model CRUST1.0, our new shear-velocity model tends to enhance both slow and fast anomalies. It reveals slow anomalies at 20 km depth beneath La Réunion, Mauritius, Rodrigues Ridge, Madagascar Rise, and beneath the Central Indian spreading ridge. These structures can clearly be associated with increased crustal thickness and/or volcanic activity. Locally thickened crust beneath La Réunion and Mauritius is probably related to magmatic underplating by the hotspot. In addition, these islands are characterized by a thickened lithosphere that may reflect the depleted, dehydrated mantle regions from which the crustal melts where sourced. Our tomography model is available as electronic supplement.

Sonographically guided, transcatheter foam sclerotherapy of the great saphenous vein

Phlebologie ◽  
2007 ◽  
Vol 36 (06) ◽  
pp. 309-312 ◽  
Author(s):  
T. Schulz ◽  
M. Jünger ◽  
M. Hahn
Keyword(s):  
Saphenous Vein ◽  
Great Saphenous Vein ◽  
Clinical Stage ◽  
Clinical Signs ◽  
Cost Effective ◽  
Duplex Sonography ◽  
Foam Sclerotherapy ◽  
Average Loss ◽  
One Year ◽  
The Cost

Summary Objective: The goal of the study was to assess the effectiveness and patient tolerability of single-session, sonographically guided, transcatheter foam sclerotherapy and to evaluate its economic impact. Patients, methods: We treated 20 patients with a total of 22 varicoses of the great saphenous vein (GSV) in Hach stage III-IV, clinical stage C2-C5 and a mean GSV diameter of 9 mm (range: 7 to 13 mm). We used 10 ml 3% Aethoxysklerol®. Additional varicoses of the auxiliary veins of the GSV were sclerosed immediately afterwards. Results: The occlusion rate in the treated GSVs was 100% one week after therapy as demonstrated with duplex sonography. The cost of the procedure was 207.91 E including follow-up visit, with an average loss of working time of 0.6 days. After one year one patient showed clinical signs of recurrent varicosis in the GSV; duplex sonography showed reflux in the region of the saphenofemoral junction in a total of seven patients (32% of the treated GSVs). Conclusion: Transcatheter foam sclerotherapy of the GSV is a cost-effective, safe method of treating varicoses of GSV and broadens the spectrum of therapeutic options. Relapses can be re-treated inexpensively with sclerotherapy.

Cost Avoidance and Clinical Benefits Derived from a Pharmacy-Managed Anemia Program

2000 ◽  
Vol 35 (2) ◽  
pp. 169-175 ◽  
Author(s):  
Robert A. Quercia ◽  
Ronald Abrahams ◽  
C. Michael White ◽  
John D'Avella ◽  
Mary Campbell
Keyword(s):  
Cost Savings ◽  
Cost Effective ◽  
Hemodialysis Patients ◽  
Cost Avoidance ◽  
Number Of Patients ◽  
Epoetin Alpha ◽  
Clinical Benefits ◽  
Unit Dose ◽  
One Year ◽  
Alpha Therapy

A pharmacy-managed anemia program included distribution and clinical components, with the goal of making epoetin alpha therapy for hemodialysis patients more cost-effective. The Pharmacy Department prepared epoetin alpha doses for patients in unit-dose syringes, utilizing and documenting vial overfill. Pharmacists dosed epoetin alpha and iron (oral and intravenous) per protocol for new and established patients. Baseline data were obtained in 1994, one year prior to implementation of the program, and were re-evaluated in 1995 and 1998. Cost avoidance from utilization of epoetin alpha vial overfill in 1995 and 1998 was $83,560 and $91,148 respectively. In 1995 and 1998, cost avoidance from pharmacy management of anemia was $191,159 and $203,985 respectively. The total cost avoidance from 1995 through 1998 was estimated at $1,018,638. The number of patients with hematocrits under 31% decreased from 32% in 1994 to 21% and 14% in 1995 and 1998 respectively. We conclude that a pharmacy-managed anemia program for hemodialysis patients results in significant cost savings and better achievement of target hematocrits.

Moray Firth marine fouling communities

1986 ◽  
Vol 91 ◽  
pp. 213-220 ◽  
Author(s):  
Gordon B. Picken
Keyword(s):  
Shallow Water ◽  
Depth Range ◽  
Soft Corals ◽  
Fouling Communities ◽  
Algal Cover ◽  
Marine Fouling ◽  
Moray Firth ◽  
Hanging Chain ◽  
Fouling Organisms

SynopsisFouling communities typical of shallow water inshore sites were found at three locations in the Moray Firth. At each, an initial background cover of solitary tubeworms and barnacles was overgrown by secondary fouling organisms. On the piles of Nigg jetty, overgrowth consisted of mussels in the depth range 0–6 m and hydroids, sponges, soft corals and anemones from 6–26 m. Buoys in the approaches to Cromarty Firth were completely covered by a mixture of algae and mussels. Sunlit areas of the float cleaned annually bore a diverse algal cover, whereas uncleaned shaded areas and the freely hanging chain had three-year-old mussels up to 7 cm long. Mussel fouling extended down the chain to within 1 m of the seabed at 26 m depth. Concrete anchor blocks on the seabed were covered with solitary tubeworms and hydroids. Steel piled platforms in the Beatrice Field were completely fouled after four years. Mussels and seaweeds were abundant from 0–5 m. In the depth range 8–35 m the background calcareous layer was overgrown by soft corals up to 10 cm long and hydroids. From 35 m to the seabed at 46 m, soft overgrowth was provided mainly by hydroids and ascidians, with only a few small corals.

scholarly journals Microearthquake seismicity and focal mechanisms at the Rodriguez Triple Junction in the Indian Ocean using ocean bottom seismometers

2001 ◽  
Vol 106 (B12) ◽  
pp. 30689-30699 ◽  
Author(s):  
Kei Katsumata ◽  
Toshinori Sato ◽  
Junzo Kasahara ◽  
Naoshi Hirata ◽  
Ryota Hino ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Focal Mechanisms ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometers ◽  
The Indian Ocean

scholarly journals Ocean-Bottom Seismographs Based on Broadband MET Sensors: Architecture and Deployment Case Study in the Arctic

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3979
Author(s):  
Artem A. Krylov ◽  
Ivan V. Egorov ◽  
Sergey A. Kovachev ◽  
Dmitry A. Ilinskiy ◽  
Oleg Yu. Ganzha ◽  
...  
Keyword(s):  
Site Response ◽  
The Arctic ◽  
Laptev Sea ◽  
Ocean Bottom ◽  
Arctic Seas ◽  
Shirshov Institute ◽  
Study Results ◽  
Ocean Bottom Seismographs ◽  
The Laptev Sea

The Arctic seas are now of particular interest due to their prospects in terms of hydrocarbon extraction, development of marine transport routes, etc. Thus, various geohazards, including those related to seismicity, require detailed studies, especially by instrumental methods. This paper is devoted to the ocean-bottom seismographs (OBS) based on broadband molecular–electronic transfer (MET) sensors and a deployment case study in the Laptev Sea. The purpose of the study is to introduce the architecture of several modifications of OBS and to demonstrate their applicability in solving different tasks in the framework of seismic hazard assessment for the Arctic seas. To do this, we used the first results of several pilot deployments of the OBS developed by Shirshov Institute of Oceanology of the Russian Academy of Sciences (IO RAS) and IP Ilyinskiy A.D. in the Laptev Sea that took place in 2018–2020. We highlighted various seismological applications of OBS based on broadband MET sensors CME-4311 (60 s) and CME-4111 (120 s), including the analysis of ambient seismic noise, registering the signals of large remote earthquakes and weak local microearthquakes, and the instrumental approach of the site response assessment. The main characteristics of the broadband MET sensors and OBS architectures turned out to be suitable for obtaining high-quality OBS records under the Arctic conditions to solve seismological problems. In addition, the obtained case study results showed the prospects in a broader context, such as the possible influence of the seismotectonic factor on the bottom-up thawing of subsea permafrost and massive methane release, probably from decaying hydrates and deep geological sources. The described OBS will be actively used in further Arctic expeditions.

Magnetic properties of PM in indoor/outdoor domestic environments 

2021 ◽  
Author(s):  
Aruã Da Silva Leite ◽  
Melina Macouin ◽  
Sonia Rousse ◽  
Jean-François Leon ◽  
Loïc Drigo ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Cost Effective ◽  
Tree Bark ◽  
Indoor Environments ◽  
Magnetic Mineralogy ◽  
Magnetic Methods ◽  
Tree Barks ◽  
Domestic Environments ◽  
One Year ◽  
The City

<p>The finer fraction of the particulate matter (PM) is the most harmful health wise, as it has more capacity to reach deeper parts of the respiratory system. Among other constituents, PM also contains iron oxides, allowing for the use of magnetic methods in its investigation as proxies for the whole of PM. Those methods present advantages in comparison to traditional ones, being quick, cost effective and sensible to investigate iron oxides among PM. </p><p>To better understand the risks related to PM exposition in the domestic context, the assessment of magnetic parameters may be used in outdoor and indoor environments, giving us information on the concentration of iron oxides (and consequently, PM) and its dispersion from one environment to the other. </p><p>We developed a citizen sciences experiment in the city of Toulouse, France. Tree barks were used as bio-collectors. Garlands composed of tree bark pieces were distributed to the population in May-2019, and placed in both indoors and outdoors of flats and homes to capture PM. They were retrieved after one year. Measurement of magnetic susceptibility, ARM, SIRM, S -ratio and estimation of superparamagnetic concentration were performed. A total of 86 bio-collectors kits were successfully analyzed. The preliminary results indicate a higher concentration of iron oxides outdoors, with a mean difference between outdoor and indoor measurements of 6.58x10<sup>-9</sup>m<sup>3</sup>/kg and 1.38x10<sup>-5</sup>Am<sup>2</sup>/kg in susceptibility and SIRM respectively. The concentration of the SP fraction also follows this trend of higher outdoor values. The magnetic mineralogy is mostly dominated by low coercivity magnetite-like carriers.</p><div> <div> <div> </div> </div> <div> <div> </div> </div> </div>

Comparison of the S/N ratios of low-frequency hydrophones and geophones as a function of ocean depth

1981 ◽  
Vol 71 (5) ◽  
pp. 1649-1659
Author(s):  
Thomas M. Brocher ◽  
Brian T. Iwatake ◽  
Joseph F. Gettrust ◽  
George H. Sutton ◽  
L. Neil Frazer
Keyword(s):  
Nova Scotia ◽  
Continental Margin ◽  
Low Frequency ◽  
Weather Conditions ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Scotian Shelf ◽  
Ocean Bottom Seismometers ◽  
Particle Velocities ◽  
Refraction Data

abstract The pressures and particle velocities of sediment-borne signals were recorded over a 9-day period by an array of telemetered ocean-bottom seismometers positioned on the continental margin off Nova Scotia. The telemetered ocean-bottom seismometer packages, which appear to have been very well coupled to the sediments, contained three orthogonal geophones and a hydrophone. The bandwidth of all sensors was 1 to 30 Hz. Analysis of the refraction data shows that the vertical geophones have the best S/N ratio for the sediment-borne signals at all recording depths (67, 140, and 1301 m) and nearly all ranges. The S/N ratio increases with increasing sensor depth for equivalent weather conditions. Stoneley and Love waves detected on the Scotian shelf (67-m depth) are efficient modes for the propagation of noise.

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