Quantifying bedform migration using multi-beam sonar

Abstract

The migration rates of both medium and very large dunes in a part of the North Sea are determined from high resolution multi-beam echo soundings. From the bathymetric maps, crest positions are determined and compared. From changes in the position of these crests relative to fixed markers, the migration rates within a tidal cycle and on a seasonal time scale are calculated. The sediment transport rates derived from the migration of the bedforms compare well with theoretical estimates of the residual transport in the area.

Vertical diel dynamic of fish assemblage associated with an artificial reef (Northern Adriatic Sea)

“…These maps help define the geological variability of the seafloor and improve the understanding of the processes that control the distribution and transport of bottom sediments, as well as the distribution of benthic habitats and associated infaunal community structures (Popper et al, 2006). Although shallow-water multibeam sonar technology (MBES) has been largely employed in mapping seabed morphology and composition (Augustin et al, 1996;Cauwenberghe, 1996;Mitchell, 1996;Shaw et al, 1997;Kammerer et al, 1998;Acosta et al, 2001;Dziak et al, 2001;Beyer et al, 2005;Knaapen et al, 2005;Chakraborty et al, 2006;Mayer, 2006), pipeline routes (Hansen and Simonis, 1994;Clasper, 1996;Paton et al, 1997; Ross et al, 2004), coral reefs (Grigg et al, 2002; Hovland et al, 2002;Conway et al, 2005;Roberts et al, 2005), and searching wrecks (Singh et al, 2000;Lawrence et al, 2001;Mayer and Kenneth, 2001;Mayer et al, 2003), it has not been used often in the fine detection of reef units, or to investigate their horizontal and vertical movements and subsidence (Shyue, 1998;Shyue and Yang, 2002).Starting with the above considerations, we carried out an assessment study at a 9-year old artificial reef deployed in the northern Adriatic Sea using an acoustic method involving both multibeam sonar for artificial reef mapping and a scientific echosounder for analysing fish distribution and movements during diel cycles at different periods of the year. The aim was to investigate the distribution of the reef fish assemblage in relation to the arrangement and state of the structures.…”

Estimation of dimensions and orientation of multiple riverine dune generations using spectral moments

“…It has become possible to investigate quantitatively in far more detail important aspects of bottom surface roughness and to verify geomorphological processes responsible for bedform formation through interactions between sediments and water flow (e.g. Bartholomä et al 2004;Knaapen et al 2005;Parsons et al 2005;Knaapen 2008;Barnard et al 2011).…”

Autonomous Underwater Vehicles as Tools for Deep-Submergence Archaeology

“…The sensor suites appropriate for AUV and ROV survey operations have become identical because of the shrinking size of high-frequency multi-beam sonars and high-resolution and dynamic-range cameras. The results shown in Figs 6,8, and 9 were produced using 12-bit Prosilica cameras, a 2250 kHz Blueview multi-beam sonar, and a single 532 nm laser line for structured light imaging.…”

“…Even in shallow water the superior handling of AUVs, with steady speed, minimal pitch and roll motions, constant altitude control, and efficient turns, makes them attractive platforms in comparison with tow bodies and hull-mounted systems on surface vessels. The data products are actively used in marine geology for topics ranging from submarine volcanoes to sand ripples [1][2][3][4][5][6][7][8], marine archaeology [9][10][11][12], oil exploration [13], habitat mapping [14][15][16], and sea ice mapping [17][18][19].…”