Ground-truthing 11- to 12-kHz side-scan sonar imagery in the Norwegia-Greenland Sea: Part I: Pockmarks on the Vestnesa Ridge and Storegga slide margin

1999 ◽  
Vol 19 (1-2) ◽  
pp. 97-110 ◽  
Author(s):  
P. R. Vogt ◽  
J. Gardner ◽  
K. Crane ◽  
E. Sundvor ◽  
F. Bowles ◽  
...  
Keyword(s):  
Greenland Sea ◽  
Side Scan Sonar ◽  
Ground Truthing ◽  
Storegga Slide

Ground-Truthing 11- to 12-kHz side-scan sonar imagery in the Norwegian-Greenland Sea: Part II: Probable diapirs on the Bear Island fan slide valley margins and the Vøring Plateau

1999 ◽  
Vol 19 (1-2) ◽  
pp. 111-130 ◽  
Author(s):  
P. R. Vogt ◽  
K. Crane ◽  
E. Sundvor ◽  
B. O. Hjelstuen ◽  
J. Gardner ◽  
...  
Keyword(s):  
Greenland Sea ◽  
Side Scan Sonar ◽  
Ground Truthing

scholarly journals Vertical Configuration of a Side Scan Sonar for the Monitoring of Posidonia oceanica Meadows

2021 ◽  
Vol 9 (12) ◽  
pp. 1332
Author(s):  
Susana Llorens-Escrich ◽  
Elena Tamarit ◽  
Sebastián Hernandis ◽  
Noela Sánchez-Carnero ◽  
Miguel Rodilla ◽  
...  
Keyword(s):  
Low Cost ◽  
Acoustic Method ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Canopy Height ◽  
User Friendliness ◽  
Side Scan Sonar ◽  
Acoustic Data ◽  
Ecosystem Indicators ◽  
Ground Truthing

Posidonia oceanica meadows are ecosystem engineers that play several roles in marine environment maintenance. In this sense, monitoring of the spatial distribution and health status of their meadows is key to make decisions about protecting them against their degradation. With the aim of checking the ability of a simple low-cost acoustic method to acquire information about the state of P. oceanica meadows as ecosystem indicators, ground-truthing and acoustic data were acquired over several of these meadows on the Levantine coast of Spain. A 200 kHz side scan sonar in a vertical configuration was used to automatically estimate shoot density, canopy height and cover of the meadows. The wide athwartship angle of the transducer together with its low cost and user friendliness entail the main advantages of this system and configuration: both improved beam path and detection invariance against boat rolling. The results show that canopy height can be measured acoustically. Furthermore, the accumulated intensity of the echoes from P. oceanica in the first 30 centimeters above the bottom is indirectly related to shoot density and cover, showing a relation that should be studied deeply.

Benthic Habitats and the Effects of Fishing

2005 ◽  
Author(s):  
Keyword(s):  
Anthropogenic Impacts ◽  
Data Sets ◽  
Side Scan Sonar ◽  
Shallow Subsurface ◽  
Natural Processes ◽  
Landscape Alteration ◽  
Ground Truthing ◽  
Processing Techniques ◽  
Data Acquisition And Processing ◽  
Coastal Louisiana

Coastal Louisiana, like many deltaic land masses, faces continued landscape alteration from natural processes and anthropogenic impacts that affect estuarine habitat. The most promising steps to slow/ mitigate these changes are river diversions that introduce freshwater and sediment to river-flanking environments and to help establish ideal salinities over historic oyster grounds. Critical to the success of these programs is a rapid and accurate means to qualify and quantify changes in oyster habitat. Digital high-resolution acoustic instrumentation linked to modern data acquisition and processing software was used to build baseline of information for evaluating future changes in shallow water bottoms, with special emphasis on oyster habitats. Application of digital side-scan sonar (100 and 500 kHz), a broad-spectrum sub-bottom profiler (4-24 kHz) for rapidly acquiring water column, surficial and shallow subsurface was used to map over 10,000 ha of water bottom. Geo-referenced side scan sonar mosaics were incorporated into a GIS data base. These data sets, “calibrated” with surface sampling, coring, and other “ground truthing” have established that numerically indexed acoustic reflectance intensities correlate closely with surface shell and oyster reef density. With image processing techniques to analyze mosaic reflectance patterns, we estimated the percent and total acreage of several bottom types.

scholarly journals Testing Side-Scan Sonar and Multibeam Echosounder to Study Black Coral Gardens: A Case Study from Macaronesia

2020 ◽  
Vol 12 (19) ◽  
pp. 3244
Author(s):  
Karolina Czechowska ◽  
Peter Feldens ◽  
Fernando Tuya ◽  
Marcial Cosme de Esteban ◽  
Fernando Espino ◽  
...  
Keyword(s):  
Habitat Characteristics ◽  
Side Scan Sonar ◽  
Multibeam Echosounder ◽  
Marine Communities ◽  
Bathymetric Data ◽  
Black Coral ◽  
Black Corals ◽  
Distribution And Ecology ◽  
Ground Truthing

Black corals (order Antipatharia) are important components of mesophotic and deep-water marine communities, but due to their inaccessibility, there is limited knowledge about the basic aspects of their distribution and ecology. The aim of this study was to test methodologies to map and study colonies of a branched antipatharian species, Antipathella wollastoni, in the Canary Islands (Spain). Acoustic tools, side-scan sonar (SSS), and a multibeam echosounder (MBES), coupled with ground-truthing video surveys, were used to determine the habitat characteristics of Antipathella wollastoni. Below 40 m depth, colonies of increasing height (up to 1.3 m) and abundance (up to 10 colonies/m2) were observed, particularly on steep and current-facing slopes on rocky substrates. However, coral presence was not directly imaged on backscatter mosaics and bathymetric data. To improve this situation, promising initial attempts of detecting Antipathella wollastoni by utilizing the MBES water column scatter in an interval for 0.75 m to 1 m above the seafloor are reported.

scholarly journals Inexpensive Video Drop-camera for Surveying Sensitive Benthic Habitats: Applications from Glass Sponge (Hexactinellida) Reefs in Howe Sound, British Columbia

2017 ◽  
Vol 131 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Lena Clayton ◽  
Glen Dennison
Keyword(s):  
British Columbia ◽  
Software Package ◽  
Fishing Gear ◽  
Benthic Habitats ◽  
Glass Sponge ◽  
Side Scan Sonar ◽  
Cost Efficient ◽  
Ground Truthing ◽  
The Impact ◽  
Sponge Bioherms

Where marine waters are shallow and bathymetric features are steep, the typically employed multi-beam side scan sonar is not always reliable for identifying complex biological structures. Here, we present a cost-efficient method used in Howe Sound, British Columbia, for bathymetric mapping, exploration, and ground-truthing of glass sponge bioherms. A simple depth sounder and software package was used to produce bathymetric maps. From these maps, prospective sites were selected and surveyed to investigate bioherm presence with a simple drop-camera towed off the bow of a small drifting vessel during calm seas. This method was used during a 4-year citizen science initiative that led to the discovery of 12 glass sponge bioherms in Howe Sound, the first step in protecting these globally unique reefs from the impact of bottom-contact fishing, anchoring, and potential industrial contamination. Before our work using this method, only two glass sponge bioherms had been identified in Howe Sound. The method also proved effective as a means to quantify damage to bioherms from fishing gear.

Indian Rocks Beach side-scan sonar mosaic map

2000 ◽  
Author(s):  
S.E. Harrison ◽  
S.D. Locker ◽  
A.C. Hine ◽  
D.C. Twichell
Keyword(s):  
Side Scan Sonar ◽  
Mosaic Map

Late Quaternary palaeo-oceanography of the Denmark Strait overflow pathway, South-East Greenland margin

1998 ◽  
Vol 180 ◽  
pp. 163-167
Author(s):  
Antoon Kuijpers ◽  
Jørn Bo Jensen ◽  
Simon R . Troelstra ◽  
And shipboard scientific party of RV Professor Logachev and RV Dana
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Deep Convection ◽  
Conveyor Belt ◽  
Water Masses ◽  
Labrador Sea ◽  
Greenland Sea ◽  
The North ◽  
Denmark Strait ◽  
The North Atlantic

Direct interaction between the atmosphere and the deep ocean basins takes place today only in the Southern Ocean near the Antarctic continent and in the northern extremity of the North Atlantic Ocean, notably in the Norwegian–Greenland Sea and Labrador Sea. Cooling and evaporation cause surface waters in the latter region to become dense and sink. At depth, further mixing occurs with Arctic water masses from adjacent polar shelves. Export of these water masses from the Norwegian–Greenland Sea (Norwegian Sea Overflow Water) to the North Atlantic basin occurs via two major gateways, the Denmark Strait system and the Faeroe– Shetland Channel and Faeroe Bank Channel system (e.g. Dickson et al. 1990; Fig.1). Deep convection in the Labrador Sea produces intermediate waters (Labrador Sea Water), which spreads across the North Atlantic. Deep waters thus formed in the North Atlantic (North Atlantic Deep Water) constitute an essential component of a global ‘conveyor’ belt extending from the North Atlantic via the Southern and Indian Oceans to the Pacific. Water masses return as a (warm) surface water flow. In the North Atlantic this is the Gulf Stream and the relatively warm and saline North Atlantic Current. Numerous palaeo-oceanographic studies have indicated that climatic changes in the North Atlantic region are closely related to changes in surface circulation and in the production of North Atlantic Deep Water. Abrupt shut-down of the ocean-overturning and subsequently of the conveyor belt is believed to represent a potential explanation for rapid climate deterioration at high latitudes, such as those that caused the Quaternary ice ages. Here it should be noted, that significant changes in deep convection in Greenland waters have also recently occurred. While in the Greenland Sea deep water formation over the last decade has drastically decreased, a strong increase of deep convection has simultaneously been observed in the Labrador Sea (Sy et al. 1997).

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