Not logged in
Data Publisher for Earth & Environmental Science

Blanchot, Jean; Rodier, Martine (1996): Phytoplankton abundance during L'Atalante cruise EBENE. PANGAEA,, Supplement to: Blanchot, J; Rodier, M (1996): Picophytoplankton abundance and biomass in the western tropical Pacific Ocean during the 1992 El Niño year: results from flow cytometry. Deep Sea Research Part I: Oceanographic Research Papers, 43(6), 877-895,

Always quote above citation when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

Natural populations of phytoplankton from the western tropical Pacific Ocean were analyzed by flow cytometry from a transect along 165°E between 20°S and 7°N. The abnormal hydrological situation corresponded to a weak El Niño event, with no equatorial upwelling and a marked nutrient ridge centered on 10°S. Prochlorophytes dominated numerically everywhere along the vertical, whatever the depth, in the 0-160-m layer (96% of cell abundance). Paradoxically, the highest concentrations, up to 4.4 x 10**5 cells/ml, were found in oligotrophic waters (< 0.1 µM NO3). In contrast, the highest concentrations of orange cyanobacteria and redfluorescing picoeukaryotes were observed when nitrate was present in the photic layer, i.e. around 10°S (up to 6.4 x 10**4 cells/ml and 1.3 x 10**4 cells/ml), and, to a lesser extent in the vicinity of the deep nitracline north of 8°S. Along the transect we encountered two hydrological situations, characterized by different community structures. The first one, found from 15°S to 7°N, except at 10°S, was a two-layer structure (Typical Tropical Structure, TTS) defined by a strong pycnocline in the upper 180 m and a well-marked nitracline. In this region, Prochlorococcus and picoeukaryotes co-dominated the 180-m integrated fluorescence and carbon biomass, but Prochlorococcus were the major component in the upper nitrate-depleted layer, while picoeukaryotes dominated the underlying rich layer. Inversely, Synechococcus were a relatively minor contributor to fluorescence (~4%) and phytoplankton biomass (< 1%) in comparison to the other cell types. The second structure observed in the southernmost part of the transect (20°S-16°S) was defined by the absence of a density gradient, and therefore by deep vertical mixing. In this case, the concentration of Prochlorococcus in the upper nitrate-depleted layer was reduced, whereas Synechococcus percentage contribution in the upper 180 m was significantly higher than in the TTS ( > 30% of total fluorescence and ~4% of carbon biomass). According to our results, we discuss the expected role of each phytoplankton group in the regenerated and new production. Finally, we discuss the importance of cell size as a factor in the expected roles of the different phytoplankton groups in the carbon sink.
Median Latitude: -1.467241 * Median Longitude: -179.910460 * South-bound Latitude: -7.983333 * West-bound Longitude: 179.850000 * North-bound Latitude: 6.000000 * East-bound Longitude: -179.800000
Date/Time Start: 1996-10-26T10:44:00 * Date/Time End: 1996-11-11T07:54:00
Minimum DEPTH, water: m * Maximum DEPTH, water: 202 m
EBENE_001 * Latitude: -7.983333 * Longitude: -179.850000 * Date/Time: 1996-10-26T10:44:00 * Location: Equatorial Pacific * Campaign: EBENE * Basis: L Atalante * Device: CTD/Rosette (CTD-RO)
EBENE_002 * Latitude: -6.983333 * Longitude: -179.833333 * Date/Time: 1996-10-26T20:52:00 * Location: Equatorial Pacific * Campaign: EBENE * Basis: L Atalante * Device: CTD/Rosette (CTD-RO)
EBENE_003 * Latitude: -5.983333 * Longitude: -179.850000 * Date/Time: 1996-10-27T05:43:00 * Location: Equatorial Pacific * Campaign: EBENE * Basis: L Atalante * Device: CTD/Rosette (CTD-RO)
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Event labelEvent
2Date/Time of eventDate/Time
3Latitude of eventLatitude
4Longitude of eventLongitude
5DEPTH, waterDepth watermGeocode
6CyanobacteriaCyanobact#/mlBlanchot, JeanCounting by flow cytometer
7MicroalgaeMicroalgae#/mlBlanchot, JeanCounting by flow cytometer
8ProchlorophytesProchlorophytes#/mlBlanchot, JeanCounting by flow cytometer
4613 data points

Download Data

Download dataset as tab-delimited text (use the following character encoding: )

View dataset as HTML (shows only first 2000 rows)