DIAPALIS 8
Type | Oceanographic cruise |
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Set | This cruise is part of the set DIAPALIS |
Ship | Alis |
Ship owner | IRD |
Dates | 09/06/2003 - 14/06/2003 |
Chief scientist(s) | NEVEUX Jacques |
OBSERVATOIRE OCEANOLOGIQUE DE BANYULS (OSU-OOB) Laboratoire Arago BP 44 66650 BANYULS-SUR-MER +33 4 68 88 73 15 |
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DOI | 10.17600/3100080 |
Objective | 1) Complementing observations on cyanobacteria made during previous cruises and in monthly monitoring done in the south-western lagoon and in the ocean beyond the Dumbea pass. 2) Determining and comparing the abundance of cyanobacteria from Trichodesmium, Synechococcus and Prochlorococcus genera between various ocean areas studied to the east (Loyalty island channel), the south-east (south of Isle of Pines), and the west of New Caledonia. Studying the related physical-chemical characteristics including iron. 3) Measuring the relative importance of surface primary production in the >10 µm size fraction containing the Trichodesmium. 4) Highlighting the presence of an upwelling in the ocean on the west coast slightly offshore from the reef, under the action of the south-easterly trade winds and specifying its impact on the phytoplankton communities' structure and the relative abundance of cyanobacteria. The chlorophyll biomasses are usually highest during the month of June in this region. 5) Characterizing the exchanges between lagoon and ocean at the Dumbea passage using ADCP measurements beyond the pass and physical-chemical and biological characteristics in the water on each side of the pass during two tidal cycles. 6) Taking marine optical measurements to assess diazotrophic cyanobacteria abundance from water color satellite images. Three set points were occupied for about 6 hours: 1) Loyalty islands channel (167 deg 00'E; 21 deg 50'S) 2) South-east of Grande Terre (south of the isle of Pines: 167 deg 30'E; 20 deg 37'S) 3) south-west of Noumea (166 deg 10'E; 22 deg 27'S). 20 short stations (30 mins to 1 h) 7 in the south-eastern lagoon, 4 in the south-western lagoon and 9 outside of the lagoon. This cruise fell under the IRD DIAPAZON (Cyano and Lodyc) and INSU PROOF (JGOFS-France) programs. |