Massive icebergs, alteration in primary food resources and c

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TitleMassive icebergs, alteration in primary food resources and change in benthic communities at Cape Evans, AntarcticaAbstractThe presence of massive icebergs in the Southwestern Ross Sea (Antarctica) in the early-to-mid-2000s changed the regional sea ice regime and phytoplankton productivity. We exploit data on benthic macro- and megafaunal communities collected on six occasions between 2001 and 2009 in the shallow waters adjacent to Cape Evans to link these oceanographic shifts to changes in benthic ecology. Changes in the abundance of individual species and community composition were generally strongest, and mostly negative, in 2002 and 2003, which exhibited the largest decrease in water column productivity and thick and persistent sea ice. This pattern of decreasing numbers from the start of sampling in 2001 to the lowest values in 2003 is consistent with the impact of the icebergs and a lagged response on the part of the benthic populations in response to food shortage. The patterns of stronger effects on macrofauna than on megafauna, and on abundance rather than species richness, are consistent with a change in food supply and/or recruitment for short-lived species, rather than a physical disturbance effect. Nevertheless, recovery patterns are likely to reflect changes in benthic communities associated with larval supply and changes in top-down control after the years of predicted lowest food supply. There are many potential manifestations of climate change in Antarctica, and many of the ecological responses to environmental change are likely to be mediated through the foodweb. Long-term studies in different locations are essential if we are to understand and forecast changes in sea-floor ecosystems. Copyright 2011 Blackwell Verlag GmbH.AcknowledgementsWe thank Paul for his inspiration, for introducing one of us (S.F.T.) to the splendour of AntarcticÅ› benthic ecosystems; he has consistently sought to develop and encourage international collaboration and we thank him for this. From his PhD research using dog bowls and dynamite on the Washington coast, Paul has been at the forefront of disturbance ecology research in marine systems, and his work is fundamental to our understanding of environmental effects in coastal systems. We would also like to thank our Italian Antarctic colleagues, particularly Riccardo Cattaneo-Vietti and Mariachiara Chiantore, for allowing us the space to begin to understand changes over time in Antarctica. We thank Chazz Marriott and Greig Funnell for video analysis, Ron Ovenden, Sarah Hailes and Scott Edhouse for sediment analyses, and Geoff Read (polychaetes) and Graham Bird (tanaids) for taxonomic assistance. For the diving we thank Greig Funnell, Owen Anderson, Chazz Marriott, Ian Hawes, Anne-Maree Schwarz, Luca Chiaroni, Drew Lohrer Alf Norkko, Neil Andrew and our dive supervisors Steve Mercer, Rod Budd and Jenny Beaumont. Alf Norkko and Neil Andrew are thanked for their valuable input to the early phases of this research, and Takeshi Tamura for unpublished information on changes in the Ross Sea polynya in the years following the icebergs. We are grateful to Antarctica New Zealand for providing excellent logistical support. This work has been funded by the New Zealand Ministry of Fisheries (ZBD2001/02, ZBD2002/01 and ZBD2006/03), NIWA-NSOF and the NZ Foundation for Research Science and Technology International Polar Year project COX01707.

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1st AuthorThrush, S.AuthorThrush, S.Cummings, V.Year2011JournalMarine EcologyVolume32Number3Pages289-299DOI10.1111/j.1439-0485.2011.00462.xKeywordsabundancebenthosclimate changeclimate effectcommunity compositionecological impactecosystem responseenvironmental changefood supplyfood webicebergprimary productionrecruitment (population dynamics)species richness, AntarcticaCape EvansEast AntarcticaRoss IslandRoss SeaSouthern Ocean, rank5Author KeywordsBenthic communitiesFood supplyIcebergLong-term studyRoss sea

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TypeArticleCitationThrush, S. and Cummings, V. (2011) Massive icebergs, alteration in primary food resources and change in benthic communities at Cape Evans, Antarctica. Marine Ecology, 32(3): 289-299 doi:10.1111/j.1439-0485.2011.00462.x IdentifierThrush2011Relevancerank5