Optical imaging of mesopelagic particles indicates deep carbon flux beneath a natural iron-fertilized bloom in the Southern Ocean
| Type | Article | ||||||||
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| Date | 2011-05 | ||||||||
| Language | English | ||||||||
| Author(s) | Jouandet Marie-Paule1, Trull Thomas W.1, 2, Guidi Lionel3, Picheral Marc4, Ebersbach Friederike5, Stemmann Lars4, Blain Stephane6, 7 | ||||||||
| Affiliation(s) | 1 : Univ Tasmania, Inst Marine & Antarct Studies, Antarct Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas, Australia. 2 : Commonwealth Sci & Ind Res Org Marine & Atmosphe, Hobart, Tas, Australia. 3 : Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. 4 : Univ Paris 06, Lab Oceanog Villefranche, Villefranche Sur Mer, France. 5 : Univ Bremen, Int Grad Sch Marine Sci GLOMAR, Bremerhaven, Germany. 6 : Univ Paris 06, UMR 7621, Lab Oceanog Microbienne LOMIC, Observ Oceanol Banyuls Mer, F-75252 Paris 05, France. 7 : Scientific national research center, UMR 7621, LOMIC, Observatoire Océanologique, Banyuls sur Mer, France |
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| Source | Limnology And Oceanography (0024-3590) (Amer Soc Limnology Oceanography), 2011-05 , Vol. 56 , N. 3 , P. 1130-1140 | ||||||||
| DOI | 10.4319/lo.2011.56.3.1130 | ||||||||
| WOS© Times Cited | 30 | ||||||||
| Abstract | We recorded vertical profiles of size distributions of particles (ranging from 0.052 to several mm in equivalent spherical diameter) in the natural iron-fertilized bloom southeast of Kerguelen Island (Southern Ocean) and in surrounding high-nutrient, low-chlorophyll (HNLC) waters with an Under Water Video Profiler during the Kerguelen Ocean and Plateau Compared Study cruise (Jan-Feb 2005). Total particle numerical abundance and total particle volume (TPV) in the 0-200-m layer were respectively 3-fold and 20-fold higher in the bloom, and integrated TPV was correlated to integrated chlorophyll concentration. The difference persisted well into the ocean interior with a 10-fold higher TPV at 400-m depth beneath the natural iron-fertilized bloom. Below 400 m, increases in TPV values at the bloom stations reflect the suspension of bottom sediments. Bloom waters had a greater proportion of large particles from the surface to 400 m and also exhibited an increase of this proportion with depth compared to HNLC waters. Multiple visits to the bloom reference Sta. A3, suggest preferential removal of large particles as the bloom declined. Comparing our particle abundance size spectra with those observed previously in polyacrylamide gel-filled sediment traps allows us to estimate mesopelagic particle sinking rates. These results suggest that particles sink faster in the HNLC waters than beneath the bloom. The fact that sinking speeds were not a simple monotonic function of particle size and varied spatially highlights the need to go beyond parameterizations of sinking rate as a function of size alone. | ||||||||
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