4th International Submarine Canyon Symposium (INCISE2018)

5-7 November 2018, Shenzhen, CHINA

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This is the detail of Submarine canyons as centres of bioturbation activity and distinct ecosystem functioning

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Author
Craig M. Robertson
Co-Author(s)
Demopoulos AWJ, Bourque JR, Mienis F, Duineveld GCA, Lavaleye MSS, Koivisto RK, Brooke SD, Ross SW, Rhode M and Davies AJ
Abstarct Title
Submarine canyons as centres of bioturbation activity and distinct ecosystem functioning
Abstarct Body
The deep-sea benthos occupies more than three quarters of the planet’s surface, yet our knowledge of how benthic communities contribute to ecosystem processes is still in infancy. Submarine canyons are known as conduits of organic matter and sediments from shelf to abyssal plains and are often associated with distinct macrobenthic communities, enhanced diversity and standing stocks compared to neighbouring slope environments. However, whole community canyon system studies assessing how these communities function and contribute to important deep-sea sedimentary ecosystem processes are lacking. To investigate how environmental conditions within canyons can alter ecosystem function, this study examined the functional differences between two canyons and adjacent slopes macrofaunal communities in the Mid-Atlantic Bight region in the western north Atlantic. A total of 49 trait modalities across 10 biological traits were used and showed that higher functional richness was present within upper and middle canyon communities compared to slope communities across the studied depth gradient. Lower canyon communities (800-900 m) were less functionally rich, a feature attributed to substantial biomass contribution of opportunistic and dominant taxa that benefited from organically-enriched sediment in the canyons. Bioturbation potential was higher in the canyons than adjacent slope, especially within Baltimore Canyon, and was attributed to the high affinities for surface and subsurface sediment modifiers and sediment ingestion or filter-feeding bioturbators. The trait affinities within canyons showed propensity for sediment reworking to greater depths, suggesting that canyon communities may enhance nutrient fluxes and burial of accumulated organic matter. The findings confirm that enhanced macrofaunal community ecosystem function and higher bioturbation occurred within the canyons compared to the adjacent slopes and provides new insight into the distinct functional roles found within canyon and slope macrofauna.
INCISE Theme
Session 3: Patterns and heterogeneity in submarine canyons
Presentation Type
Oral Presentation
Keywords
Macrofauna, Biological Traits, Ecosystem Function, Bioturbation, Disturbance

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