Mapping biotic and abiotic seafloor habitat characteristics with multi-spectral multi-beam backscatter data

Sebastiaan Mestdagh*, Qian Bai, Mirjam Snellen

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

Detailed knowledge of both the sedimentological and ecological characteristics of the seafloor is essential when undertaking bottom-disturbing activities, but can be a challenge to obtain. Through backscatter data at different frequencies, collected with a multi-spectral multi-beam sonar, information on the structure of both the sediment surface and subsurface, and potentially also on the presence and distribution of benthic organisms, can be derived. We conducted two surveys at sea in summer 2021, in which we used an R2Sonic 2026 multi-spectral multi-beam sonar in the southern North Sea. Boxcore samples were taken to gather information on macrobenthos densities and sediment characteristics. The two studied areas were found to differ in seafloor morphology and correspondingly in the composition of the sediment composition and benthos distribution. Backscatter strength was used to classify the seafloor via the Bayesian method and via hierarchical clustering of angular variation. Relationships between the classification results for three frequencies and sediment and ecological variables were studied through redundancy analysis (RDA), for which hierarchical clustering of the angular variation in backscatter strength showed a higher model fit than Bayesian classification. We found that the density of the sand mason worm Lanice conchilega and percentages of dead shells, gravel and sand contributed most to the backscatter-based classification, with lower contributions of the percentages of mud and living bivalves. Our results suggest that acoustic backscatter can be used to delineate distinct seafloor regions, corresponding with concurrent gradients in ecological and sedimentological variables.

Original languageEnglish
Title of host publicationOCEANS 2023 - Limerick, OCEANS Limerick 2023
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages6
ISBN (Electronic)9798350332261
DOIs
Publication statusPublished - 2023
Event2023 OCEANS Limerick, OCEANS Limerick 2023 - Limerick, Ireland
Duration: 5 Jun 20238 Jun 2023

Publication series

NameOCEANS 2023 - Limerick, OCEANS Limerick 2023

Conference

Conference2023 OCEANS Limerick, OCEANS Limerick 2023
Country/TerritoryIreland
CityLimerick
Period5/06/238/06/23

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Keywords

  • backscatter
  • benthos
  • multi-beam
  • multi-spectral
  • sediment characteristics

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