Seabed habitats of the Bay of Fundy, Atlantic Canada

Abstract The Bay of Fundy, Canada, a large macrotidal embayment with the World’s highest recorded tides, was mapped using multibeam sonar systems. High-resolution imagery of seafloor terrain and backscatter strength, combined with geophysical and sampling data, reveal a suite of glacial landforms associated with the southwest margin of the Laurentide Ice Sheet. The glacial signature is overprinted by postglacial sediments and a spectrum of bedforms including flow-transverse bedforms occur as both discrete large two-dimensional dunes and as three-dimensional dunes in sand sheets, and flow-parallel bedforms consisting of numerous straight ridges. The suite of bedforms developed during the Holocene, as tidal energy increased due to the bay approaching resonance. Seafloor imagery has revealed that the Bay of Fundy supports a wide range of biological communities associated with the diverse geomorphological setting of the area. A full range of seafloor substrata is represented ranging from bedrock through various mixtures of boulders, cobbles, gravel, sand, and mud, each supporting different biological assemblages. Applying structure-from-motion (SfM) analysis, high-resolution, close-range photographs of the seabed can be used to generate 2D photomosaics and 3D topographic models of the seafloor. Future work will involve the comparison of species data with fine-scale geomorphology data extracted from the SfM analysis and multibeam sonar data to determine statistical relationships between the physical surrogates and benthos across different spatial scales to gain insight into the abiotic drivers of biological patterns on the seafloor.