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 ◽  
...  

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.

2014 ◽  
Vol 35 (9) ◽  
pp. 3286-3299 ◽  
Author(s):  
Xiekai He ◽  
Ninghua Chen ◽  
Huaguo Zhang ◽  
Bin Fu ◽  
Xiaozhen Wang

2018 ◽  
Vol 32 (5) ◽  
pp. 1102 ◽  
Author(s):  
M. Bo ◽  
M. Barucca ◽  
M. A. Biscotti ◽  
M. R. Brugler ◽  
A. Canapa ◽  
...  

The Mediterranean black coral fauna includes type species of four antipatharian genera belonging to four different families, therefore phylogenetic studies hold great potential for enhancing systematics within the order. The analysis of six Mediterranean antipatharian species by means of nuclear sequence data of internal transcribed spacer (ITS1 and ITS2) rDNA confirms the separation into different families, as was previously noted on a morphological basis, with a clear distinction of the family Leiopathidae, whose position is supported by a unique number of mesenteries and lack of spines on thicker ramifications. The position of a newly recorded black coral species for the Mediterranean basin belonging to the genus Phanopathes is discussed. Antipathes dichotoma, the type species of the genus Antipathes, on which the order Antipatharia was based, does not group with other members of the family Antipathidae. Supporting a recent finding based on mitochondrial markers, this suggests a critical need for revision of the families that will be impacted by reassignment of this nomenclaturally important taxon.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2926 ◽  
Author(s):  
Yeon Yeu ◽  
Jurng-Jae Yee ◽  
Hong Yun ◽  
Kwang Kim

Bathymetric mapping is traditionally implemented using shipborne single-beam, multi-beam, and side-scan sonar sensors. Procuring bathymetric data near coastlines using shipborne sensors is difficult, however, this type of data is important for maritime safety, marine territory management, climate change monitoring, and disaster preparedness. In recent years, the bathymetric light detection and ranging (LiDAR) technique has been tried to get seamless geospatial data from land to submarine topography. This paper evaluated the accuracy of bathymetry generated near coastlines from satellite altimetry-derived gravity anomalies and multi-beam bathymetry using a tuning density contrast of 5000 kg/m3 determined by the gravity-geologic method. Comparing with the predicted bathymetry of using only multi-beam depth data, 78% root mean square error from both multi-beam and airborne bathymetric LiDAR was improved in shallow waters of nearshore coastlines of the western Korea. As a result, the satellite-derived bathymetry estimated from the multi-beam and the airborne bathymetric LiDAR was enhanced to the accuracy of about 0.2 m.


2021 ◽  
Vol 15 (2) ◽  
pp. 99-112
Author(s):  
Agni Mochtar ◽  
Firman Setiawan ◽  
Shinatria Adhityatama

Aplikasi metode geofisika menggunakan side scan sonar dalam penelitian arkeologi bawah air belum banyak dilakukan di Indonesia. Tulisan ini memaparkan penggunaan side scan sonar untuk pemetaan dasar sungai dan identifikasi tinggalan arkeologi di dasar sungai dalam penelitian “Sungai Brantas dalam Perspektif Lanskap Kultur Maritim”, serta interpretasi hasil survei side scan sonar tersebut dalam konteks kesejarahan. Selain itu, dalam tulisan ini akan dibahas potensi pengembangan penggunaan side scan sonar dalam penelitian arkeologi bawah air di Indonesia, terutama di perairan sungai. Akuisisi data dilakukan dengan menggunakan side scan sonar Starfish 450H dengan sistem posisi GNSS Trimble R8s. Sementara itu, interpretasi diperoleh dengan melakukan analisis terhadap data peta dan arsip Belanda untuk memahami konteks temporal dari objek yang dideteksi oleh alat side scan sonar. Survei berhasil menunjukkan sedimen di dasar sungai berupa lempung dan lanau, serta beberapa objek yang diduga sebagai bangkai kapal, yang diperkirakan berasal dari pasca abad ke-19 Masehi. Hasil survei side scan sonar menunjukkan tingkat akurasi cukup hingga tinggi dan dapat menjadi pendukung penelitian arkeologi bawah air yang efisien, terutama di perairan yang keruh. Side scan sonar survey as one of the geophysics methods is still scarcely applied in underwater archaeological research in Indonesia. This paper describes the application of side scan sonar survey in mapping riverbed and identifying underwater archaeological remains in the “Sungai Brantas in the Perspective of Maritime Cultural Landscape” project, as well as interpreting its historical context based on survey results. This paper also explores the development of utilizing side scan sonar in underwater archaeological research in Indonesia, particularly in rivers. Data was acquisitioned by using the side scan sonar Starfish 450H and GNSS Trimble R8s positioning system. The interpretation was drawn by analysing related Dutch old maps and archives to understand the historical context of the survey findings. The result shows clay and silt sediment covering most of the riverbed and a number of objects, possibly shipwrecks, estimated as from the nineteenth century. The survey result has a medium to high accuracy. Thus, this method is able to serve as an efficient instrument for underwater archaeological research, especially in the low-visibility waters.


2021 ◽  
Vol 9 (12) ◽  
pp. 1332
Author(s):  
Susana Llorens-Escrich ◽  
Elena Tamarit ◽  
Sebastián Hernandis ◽  
Noela Sánchez-Carnero ◽  
Miguel Rodilla ◽  
...  

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.


2010 ◽  
Vol 67 (6) ◽  
pp. 1301-1309 ◽  
Author(s):  
George R. Cutter ◽  
Laurent Berger ◽  
David A. Demer

Abstract Cutter, G. R. Jr, Berger, L., and Demer, D. A. 2010. A comparison of bathymetry mapped with the Simrad ME70 multibeam echosounder operated in bathymetric and fisheries modes. – ICES Journal of Marine Science, 67: 1301–1309. The Simrad ME70 multibeam echosounder was designed for quantitative fisheries research and is currently installed on Ifremer's fishery survey vessel (FSV) “Thalassa” and each of the new, quiet, NOAA FSVs. The ME70 has configurable beams and transmits in the range 70–120 kHz to provide calibrated, acoustic-backscattering data throughout the detection range (fisheries mode, FM). With optional hardware and software, the ME70 can also collect soundings that potentially meet International Hydrographic Organization's S–44 Order 1 standards (bathymetric mode, BM). Furthermore, with custom algorithms and software, bathymetric data can be obtained from the ME70 operating in FM, and volume backscatter can be sampled from the ME70 operating in BM. This flexibility allows data to be concurrently collected on fish and their seabed habitat. A method is described for processing the echo amplitude and phase data from multiple split-beams formed in FM to estimate seabed range, slope, and roughness. The resulting bathymetry is compared with that collected with the ME70 operating in BM in the same area of the Bay of Biscay. A proposal is made for software development to facilitate dual-use data processing.


<strong><em>Abstract. </em></strong>Subtidal benthic habitats from the Piscataqua River, New Hampshire and Maine, have been delineated by an automated segmentation technique using bathymetry derived from multibeam echo sounder data. The map, produced by segmentation of seafloor textures, represents a hypothetical benthic habitat map that requires ground-truthing. Video mosaics are being used to ground-truth substrate composition and transitions apparent in the bathymetry data map and to describe biological features and organism occurrences and densities. Here, we describe the utility of video mosaics for ground-truthing benthic habitat characteristics and present two examples of their use. Video mosaics acquired along two transects in the Piscataqua River were used to detect substrate transitions apparent in the bathymetry that were identified as distinct hypothetical habitat types and to quantitatively assess coverages of distinct sediment conditions, density of megafaunal organisms (lobsters), and bioturbational features (crab feeding pits).


<em>Abstract.</em>—Trawl surveys were conducted to measure patterns of habitat use by newly settled red snapper <em>Lutjanus campechanus </em>at three natural banks on the inner continental shelf of Texas. Digital side-scan sonar and multibeam bathymetric data were used to define inshore (mud), ridge (shell), and offshore (mud) habitats for Freeport Rocks, Heald Bank, and Sabine Bank. Otter trawls were conducted July through September in 2003 (Heald Bank, Sabine Bank) and in 2004 (Freeport Rocks) during the settlement period of red snapper. Freeport Rocks had markedly higher densities of red snapper (91 ha<sup>⁻1</sup>) in 2004 than Heald Bank (6 ha<sup>⁻1</sup>) or Sabine Bank (<1 ha<sup>⁻1</sup>) in 2003. A significant habitat effect was observed at Heald Bank and densities were higher at offshore mud habitats; no habitat effect was detected for Freeport Rocks or Sabine Bank. Growth rates varied from 0.86 mm‧d<sup>⁻1</sup> at Sabine Bank up to 1.12 mm‧d<sup>⁻1</sup> at Freeport Rocks, and rates were higher on inshore and offshore mud than ridge habitats. Otolith-based estimates of age indicated that settlers were first detected at 22–28 d and the majority of individuals were 30–60 d. Hatch dates peaked from early June to early July in both 2003 and 2004. Results from this study indicate that both shell and inshore and offshore mud habitats associated with these natural banks serve as settlement habitat of red snapper, and all three habitats have the potential to function as nursery areas of this species.


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