Setting the stage for multi-spectral acoustic backscatter research

Abstract

The establishment of multibeam echosounders (MBES) as a mainstream tool in ocean mapping has facilitated integrative approaches towards nautical charting, benthic habitat mapping, and seafloor geotechnical surveys. The combined acoustic response of the seabed and the subsurface can vary with MBES operating frequency. At worst, this can make for difficulties in merging results from different mapping systems or mapping campaigns. At best, however, having observations of the same seafloor at different acoustic wavelengths allows for increased discriminatory power in seabed classification and characterization efforts. Here, we present results from early trials of a multispectral multibeam system (R2Sonic 2026 MBES) in the Bedford Basin, Nova Scotia. In this system, the frequency can be modified on a ping-by-ping basis, which can provide multispectral acoustic measurements with a single pass of the survey platform. We demonstrate how this capability provides improved seafloor discrimination at this site based on the different frequency responses and seafloor sediment characteristics. These innovations offer tremendous potential for application in the area of seafloor geological and benthic habitat mapping.

Geostatistical modelling of multibeam backscatter for full-coverage seabed sediment maps

“…This knowledge is crucial for efforts aiming to increase the discrimination performance. Recent studies have demonstrated that multispectral backscatter data indeed reveal that areas, showing the same acoustic responses for one frequency, differ in the acoustic response of a second frequency (Hughes Clarke, 2015;Brown et al, 2017). This implies that the use of different frequencies might be an appropriate approach to improve seabed sediment classification (Hughes Clarke, 2015) and resolve ambiguities.…”

Multi-Frequency, Multi-Sonar Mapping of Shallow Habitats—Efficacy and Management Implications in the National Marine Park of Zakynthos, Greece

“…The cumulative human-induced threats on marine biodiversity and ecosystem goods and services are increasing worldwide while habitat loss and degradation, pollution, overfishing and climate change effects are classified among the most important threats that affect the marine realm [1,2]. Yet, the successful and effective protection and conservation of the marine ecosystem largely depends on our knowledge regarding the spatial extent, the geographical range and the ecological characteristics of the resource or the habitat of interest [3]. Thus, accurate and high-resolution habitat mapping can be considered as a prerequisite in spatial marine management and conservation planning.…”

A Multispectral Bayesian Classification Method for Increased Acoustic Discrimination of Seabed Sediments Using Multi-Frequency Multibeam Backscatter Data

“…This MBES emits a series of signals between 90 and 450 kHz on a ping-by-ping basis. In Brown et al [18], the first multispectral backscatter dataset acquired with a single MBES system (R2Sonic 2026) in the Bedford Basin, Canada, was employed and analyzed. The preliminary results of this study indicate benefits for an improved understanding of seabed characteristics by using multispectral backscatter.…”