Do bioturbation and consumption affect coastal Arctic marine soft-bottom communities?

• Published in: Polar Biology
• Main Authors: Petrowski, Sina, Molis, Markus, Schachtl, Kathrin, Buschbaum, Christian
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: SPRINGER 2016
• Subjects: Arctic; Kongsfjord*; Kongsfjorden; Polar Biology; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/42817/; https://epic.awi.de/id/eprint/42817/1/Pet2016a.pdf; https://hdl.handle.net/10013/epic.49390; https://hdl.handle.net/10013/epic.49390.d001

Biotic factors such as bioturbation and predation affect abundance and species composition of marine soft-bottom communities from tropical to temperate regions, but their impact has been rarely investigated in Arctic coastal systems. By conducting a factorial manipulative field experiment, we excluded the bioturbating lugworm Arenicola marina and predacious consumers from a sedimentary nearshore area in Kongsfjorden (Spitsbergen) for 70 days to explore their role in structuring the benthic community. The removal of A. marina caused an increase in average species number by 25 %, a doubling increase in the average number of individuals and an increase in dry mass of benthic organisms by, on average, 73 % in comparison with untreated areas. Additionally, community composition was significantly modified by lugworm exclusion resulting in higher average densities of the cumacean Lamprops fuscatus (4.2-fold), the polychaete worms Euchone analis (3.7-fold) and Pygospio cf. elegans (1.5-fold), the bivalve Crenella decussata (2.8-fold) and the amphipod Crassicorophium crassicorne (1.2-fold), which primarily contribute to the observed differences. Consumer exclusion, by contrast, showed no effects on the response variables. This result was independent from bioturbation due to missing interaction between both biotic factors. We conclude that present levels of bioturbation may considerably affect Arctic coastal soft-bottom communities. In contrast, predation by macro-epibenthic consumers currently seems to be of minor importance. This might change in a predicted warmer Arctic with assumed higher predator abundances and a northward expansion of boreal consumers.