Regional Variability of Megabenthic Community Structure across the Canadian Arctic

Major climate changes are underway in the Canadian Arctic, but our ability to monitor and predict their impact on faunal community structure is hindered by the lack of baseline diversity data. This study combined megabenthic community data sampled at 78 stations from 2007 to 2011 across the Western and Eastern Canadian Arctic biogeographic units. These large biogeographic units were divided into five geographical regions to provide regional estimates of observed and predicted taxon richness. We did not detect a strong regional difference in benthic community characteristics, observing only a lower richness in the Amundsen Gulf region than in the neighboring Beaufort Sea region. The Amundsen Gulf region had the highest turnover (beta) diversity, coincident with high environmental heterogeneity. The strong and distinctive presence in the Beaufort Sea region of Saduria spp., a euryhaline isopod, demonstrated the particular influence of the Mackenzie River on the community composition of that region. Our analysis showed that in various regions, about 34% to 59% of megabenthic taxa in Canadian Arctic waters are still to be documented. This study provides useful baseline data for both national and pan-Arctic evaluations of benthic diversity in the Arctic Ocean.