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Front. Mar. Sci. | doi: 10.3389/fmars.2021.692851

Distribution of megabenthic communities under contrasting settings in deep-sea cold seeps near northwest Atlantic canyons Provisionally accepted The final, formatted version of the article will be published soon. Notify me

  • 1University of Edinburgh, United Kingdom
  • 2University of North Carolina at Wilmington, United States

Cold seeps support fragile deep-sea communities of high biodiversity and are often found in areas with high commercial interest. Protecting them from encroaching human impacts (bottom trawling, oil and gas exploitation, climate change) requires an advanced understanding of the drivers shaping their spatial distribution and biodiversity. Based on the analysis of 2,075 high-quality images from six remotely operated vehicle dives, we examined cold seep megabenthic community composition, richness, density and biodiversity at a relatively shallow (~400 m water depth) site near Baltimore Canyon (BC) and a much deeper site (~1,500 m) near Norfolk Canyon (NC), in the northwest Atlantic. We found sharp differences in the megabenthic composition between the sites, which were driven mostly by bathymetric gradients. At both BC and NC there were significant differences in megabenthic composition across habitats. Hard habitats in and around cold seeps had significantly higher values of species richness, density and biodiversity than soft habitats. Depth and habitat complexity were the leading environmental variables driving megabenthic variability. The presence of microbial mats and gas bubbling sites had a statistically significant contribution to explaining megabenthic variability mainly in the shallower BC and less in the deeper NC areas examined; drivers behind this discrepancy could be related to differences between BC and NC in terms of chemical compound fluxes and megafaunal life history characteristics. Our surveys revealed marine litter, primarily from commercial fisheries. This study highlights the importance of habitat complexity for the proliferation of highly diverse cold-seep ecosystems and underscores the importance of discovery science to inform spatial management of human activities in the deep and open ocean.

Keywords: deep sea, Chemosynthetic environments, Vulnerable Marine Ecosystems (VMEs), Climate Change, marine conservation, marine litter, Cold-water coral

Received: 09 Apr 2021; Accepted: 17 Jun 2021.

Copyright: © 2021 Cleland, Kazanidis, Roberts and Ross. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Georgios Kazanidis, University of Edinburgh, Edinburgh, EH8 9YL, United Kingdom,