title: Understanding the structure and functioning of polar pelagic ecosystems to predict the impacts of change.
abstract: The determinants of the structure, functioning and resilience of pelagic ecosystems across most of the polar regions are not well known. Improved understanding is essential for assessing the value of biodiversity and predicting the effects of change (including in biodiversity) on these ecosystems and the services they maintain. Here we focus on the trophic interactions that underpin ecosystem structure, developing comparative analyses of how polar pelagic food webs vary in relation to the environment. We highlight that there is not a singular, generic Arctic or Antarctic pelagic food web, and, although there are characteristic pathways of energy flow dominated by a small number of species, alternative routes are important for maintaining energy transfer and resilience. These more complex routes cannot, however, provide the same rate of energy flow to highest trophic-level species. Food-web structure may be similar in different regions, but the individual species that dominate mid-trophic levels vary across polar regions. The characteristics (traits) of these species are also different and these differences influence a range of food-web processes. Low functional redundancy at key trophic levels makes these ecosystems particularly sensitive to change. To develop models for projecting responses of polar ecosystems to future environmental change, we propose a conceptual framework that links the life histories of pelagic species and the structure of polar food webs.
authors.affiliation: British Antarctic Survey, NERC, Cambridge, UK e.murphy@bas.ac.uk.
authors.forename: E J
authors.identifier: 0000-0002-7369-9196
authors.initials: EJ
authors.lastname: Murphy
authors.affiliation: British Antarctic Survey, NERC, Cambridge, UK.
authors.forename: R D
authors.identifier: 0000-0002-2474-9716
authors.initials: RD
authors.lastname: Cavanagh
authors.affiliation: Institute of Marine Research, Bergen, Norway.
authors.forename: K F
authors.initials: KF
authors.lastname: Drinkwater
authors.affiliation: British Antarctic Survey, NERC, Cambridge, UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Grant
authors.affiliation: Scottish Association for Marine Science, Oban, Argyll, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Heymans
authors.affiliation: Center for Coastal and Physical Oceanography, Old Dominion University, Norfolk, VA, USA.
authors.forename: E E
authors.initials: EE
authors.lastname: Hofmann
authors.affiliation: School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Hunt
authors.affiliation: British Antarctic Survey, NERC, Cambridge, UK.
authors.forename: N M
authors.initials: NM
authors.lastname: Johnston
mesh_terms: D000864:Antarctic Regions; D001110:Arctic Regions; D044822:Biodiversity; D057231:Climate Change; D017753:Ecosystem; D020387:Food Chain; D009792:Oceans and Seas
keywords: biodiversity; climate change; ecosystem functioning; ecosystems; ocean; polar