Spatial patterns and environmental drivers of benthic infaunal community structure and ecosystem function on the New Zealand continental margin |
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Authors: | CA Pilditch D Leduc SD Nodder PK Probert DA Bowden |
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Affiliation: | 1. School of Science, University of Waikato, Hamilton, New Zealandc.pilditch@waikato.ac.nz;3. National Institute of Water and Atmospheric Research (NIWA) Ltd, Wellington, New Zealand;4. Department of Marine Science, University of Otago, Dunedin, New Zealand |
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Abstract: | To investigate regional drivers of spatial patterns in macro- and meio-faunal community structure (abundance, biomass and taxonomic diversity) and ecosystem function (sediment community oxygen consumption [SCOC]), we sampled two regions in close proximity on New Zealand's continental margin—the Chatham Rise and the Challenger Plateau. Sites (n = 15) were selected in water depths ranging from 266–1212 m to generate a gradient in sedimentary properties and, in particular, surface pelagic productivity. Both macro- and meio-fauna abundance and biomass was 2–3.5 times higher on the Chatham Rise than on the Challenger Plateau, reflecting regional differences in pelagic primary production. We also found significant inter- and intra-regional differences in macro-fauna taxonomic diversity with two distinctive site groupings in each region. Univariate and multivariate measures of macro-fauna community attributes were most strongly correlated with sediment photosynthetic pigment (explaining 24%–59% of the variation). Sediment pigment content was as equally important in explaining meio-fauna community structure (36%–7%). Unlike community structure, SCOC was most strongly correlated with depth (44%), most likely reflecting temperature effects on benthic metabolism. Our results highlight the importance of a benthic labile food supply in structuring infaunal communities on continental margins and emphasise a tight coupling between pelagic and benthic habitats. |
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Keywords: | abundance biomass Challenger Plateau Chatham Rise diversity macro-fauna meio-fauna sediment community oxygen consumption Subtropical Front |
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