Highly dynamic biological seabed alterations revealed by side scan sonar tracking of Lanice conchilega beds offshore the island of Sylt (German Bight)

Improved Interpretation of Marine Sedimentary Environments Using Multi-Frequency Multibeam Backscatter Data

“…Available studies involve surveys of cold water corals [12][13][14] and different benthic habitats and assemblages [15][16][17][18][19][20][21][22]. Remote sensing of benthic habitats remains a field of active research, which strongly benefits from the ongoing optimization of multibeam echosounder backscatter and the introduction of multi-frequency capabilities [23][24][25].…”

Impact of Sparse Benthic Life on Seafloor Roughness and High-Frequency Acoustic Scatter

“…The low abundances during the Heincke cruise of normally widespread tubeworms, confirmed during the video transects, are chiefly attributed to seasonal effects. In the early spring season, the worm tubes are poorly developed, and the settlement coverage of the specimen is lower compared to the summer season, although major changes between years have also been reported [14,39]. The high mean of spectral slope values (>4) derived from the Heincke data also indicate a lack of high-frequency roughness and suggest a low recent modification of the seafloor surface by biological processes [6].…”

“…Such trends were found for seafloors with different sedimentological composition or more contrasting bedforms [6,7] (arrow 2 and 3 in Figure 7b). Related to the presence of benthic organisms, such behavior can be caused by the increased presence of biological objects causing degradation of ripples (e.g., observed by [14]), thus reducing low-spatial-frequency roughness. However, due to the relatively low abundances of benthic life present in this study, this effect could not be observed.…”

“…The study area is located 17.5 km offshore Sylt island in the German Bight ( Figure 1) at a water depth of approximately 15 m. The region is exposed to storm events from the west and influenced by semidiurnal tides that are flood dominated. The seafloor surface and subsurface of the area have been described as homogenous sandy surfaces by [14,31,32]. A backscatter map of the study site reveals numerous patchy features.…”

“…The impact of benthic life on acoustic backscatter is both a challenge and an opportunity for environmental remote sensing. Benthic life has an impact on both lander-based [6,7,12,13] and ship-based [14][15][16][17][18][19] acoustic remote sensing tools. Conversely, these technologies have an unrealized potential to determine spatial and temporal dynamics of biologically impacted seafloor.…”