FN Archimer Export Format PT J TI Community structure across a large-scale ocean productivity gradient: Marine bird assemblages of the Southern Indian Ocean BT AF HYRENBACH, K. David VEIT, Richard R. WEIMERSKIRCH, Henri METZL, Nicolas HUNT, George L., Jr. AS 1:1;2:2;3:3;4:4;5:5; FF 1:;2:;3:;4:;5:; C1 Duke Univ, Marine Lab, Beaufort, NC 28517 USA. CSI CUNY, Dept Biol, Staten Isl, NY 10314 USA. Ctr Natl Rech Sci, Ctr Etud Biol Chize, Villiers En Bois, France. Univ Paris 06, LOCEAN IPSL, F-75252 Paris, France. Univ Calif Irvine, Dept Ecol & Evolut, Irvine, CA 92697 USA. C2 UNIV DUKE, USA CSI CUNY, USA CNRS, FRANCE IPSL, FRANCE UNIV CALIF IRVINE, USA IF 1.795 TC 49 UR https://archimer.ifremer.fr/doc/00235/34628/32969.pdf LA English DT Article CR OISO 8 OISO1 OISO2 OISO3-NIVMER98 OISO4 (VT 46) OISO5 (VT 49) VT 51 / OISO 6 VT 57 / OISO 9 VT 60 / CARAUS - OISO 10 VT 62 / CARAUS - OISO 11 VT 79 / OISO 12 VT 80 / OISO 13 VT 81 / OISO 14 BO Marion Dufresne DE ;community structure;seabirds;ocean productivity;oceanic fronts;remote sensing;species assemblages;crozet basin;Indian ocean AB Our objective was to understand how marine birds respond to oceanographic variability across the Southern Indian Ocean using data collected during an 16-day cruise (4-21 January 2003). We quantified concurrent water mass distributions, ocean productivity patterns, and seabird distributions across a heterogeneous pelagic ecosystem from subtropical to sub-Antarctic waters. We surveyed 5155 kin and sighted 15,606 birds from 51 species, and used these data to investigate how seabirds respond to spatial variability in the structure and productivity of the ocean. We addressed two spatial scales: the structure of seabird communities across macro-mega scale (1000 s km) biogeographic domains, and their coarse-scale (10 s km) aggregation at hydrographic and bathymetric gradients. Both seabird density and species composition changed with latitudinal and onshore-offshore gradients in depth, water temperature, and chlorophyll-a concentration. The average seabird density increased across the subtropical convergence (STC) from 2.4 birds km(-2) in subtropical waters to 23.8 birds km(-2) in sub-Antarctic waters. The composition of the avifauna also differed across biogeographic domains. Prions (Pachyptila spp.) accounted for 57% of all sub-Antarctic birds, wedge-tailed shearwaters (Puffinus pacificus) accounted for 46% of all subtropical birds, and Indian Ocean yellow-nosed albatross (Thallasarche carteri) accounted for 32% of all birds in the STC. While surface feeders were the most abundant foraging guild across the study area, divers were disproportionately more numerous in the sub-Antarctic domain, and plungers were disproportionately more abundant in subtropical waters. Seabird densities were also higher within shallow shelf-slope regions, especially in sub-Antarctic waters, where large numbers of breeding seabirds concentrated. However, we did not find elevated seabird densities along the STC, suggesting that this broad frontal region is not a site of enhanced aggregation. PY 2007 PD JUN SO Deep-sea Research Part I-oceanographic Research Papers SN 0967-0637 PU Pergamon-elsevier Science Ltd VL 54 IS 7 UT 000248249400006 BP 1129 EP 1145 DI 10.1016/j.dsr.2007.05.002 ID 34628 ER EF