Picoplanktonic community structure on an Atlantic transect from 50°N to 50°S

Zubkov, Mikhail V.; Sleigh, M. A.; Tarran, Glen A.; Burkill, Peter H.; Leakey, Raymond J.G.

doi:10.1016/s0967-0637(98)00015-6

Cited by 265 publications

(230 citation statements)

References 39 publications

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“…5B and 6C). Furthermore, the mean cyanobacterial biomass in surface oligotrophic regions during AMT-3 estimated from the cell counts [1.8$0.3 mg C m\ ] was comparable, within a factor of 2, to that obtained from #ow cytometry [3.3$0.4 mg C m\ ] (Zubkov et al, 1998). For AMT-3, we recalculated our total phytoplankton C estimates using #ow cytometry-derived picoplankton biomasses and found no signi"cant di!erences between these new estimates and the ones that were fully based on the microscopy cell counts.…”

Section: Phytoplankton Growth In the Oligotrophic Regionsmentioning

confidence: 65%

“…The actual rate of carbon "xation by phytoplankton can also be underestimated if intense recycling of C by the microbial food web takes place during the incubation (Peterson, 1980). However, this e!ect is unlikely to in#uence the results of short incubations (6}7 h) such as the ones we used in our study, especially considering the relatively low biomass of microzooplankton (1}3 mg C m\ , representing (10% of total microplankton biomass) and heterotrophic bacteria (2}4 mg C m\ , Zubkov et al, 1998) found in the oligotrophic gyres as compared to that of phytoplankton (6}14 mg C m\ , Figs. 6A and 7A).…”

Section: Phytoplankton Growth In the Oligotrophic Regionsmentioning

confidence: 91%

“…Cell numbers were converted into carbon (C) biomass as described by Holligan et al (1984). For picoplankton ((2 m), we calculated carbon biomass estimates by applying the conversion factors obtained by Zubkov et al (1998) during AMT-3 using size-fractionation and #ow cytometry techniques. Using the AMT-3 database, we compared total phytoplankton-C estimates based on the microscopic cell counts with C estimates in which the picoplanktonic biomass had been calculated from #ow cytometry data.…”

Section: Microplankton Stock Measurementsmentioning

confidence: 99%

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Basin-scale variability of phytoplankton biomass, production and growth in the Atlantic Ocean

Marañón

Holligan

Varela

et al. 2000

Deep Sea Research Part I: Oceanographic Research Papers

197

157

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The latitudinal distributions of phytoplankton biomass, composition and production in the Atlantic Ocean were determined along a 10,000-km transect from 503N to 503S in October 1995, May 1996 and October 1996. Highest levels of euphotic layer-integrated chlorophyll a (Chl a) concentration (75}125 mg Chl m\ ) were found in North Atlantic temperate waters and in the upwelling region o! NW Africa, whereas typical Chl a concentrations in oligotrophic waters ranged from 20 to 40 mg Chl m\ . The estimated concentration of surface phytoplankton carbon (C) biomass was 5}15 mg C m\ in the oligotrophic regions and increased over 40 mg C m\ in richer areas. The deep chlorophyll maximum did not seem to constitute a biomass or productivity maximum, but resulted mainly from an increase in the Chl a to C ratio and represented a relatively small contribution to total integrated productivity. Primary production rates varied from 50 mg C m\ d\ at the central gyres to 500}1000 mg C m\ d\ in upwelling and higher latitude regions, where faster growth rates ( ) of phytoplankton ( '0.5 d\ ) were also measured. In oligotrophic waters, microalgal growth was consistently slow [surface averaged 0.21$0.02 d\ (mean$SE)], representing (20% of maximum expected growth. These results argue against the view that the subtropical gyres are characterized by high phytoplankton turnover rates. The latitudinal variations in were inversely correlated to the changes in the depth of the nitracline and positively correlated to those of the integrated nitrate concentration, supporting the case for the role of nutrients in controlling the large-scale distribution of phytoplankton growth rates. We observed a large degree of temporal 0967-0637/00/$ -see front matter 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 -0 6 3 7 ( 9 9 ) 0 0 0 8 7 -4 variability in the phytoplankton dynamics in the oligotrophic regions: productivity and growth rates varied in excess of 8-fold, whereas microalgal biomass remained relatively constant. The observed spatial and temporal variability in the biomass speci"c rate of photosynthesis is at least three times larger than currently assumed in most satellite-based models of global productivity.

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Section: Phytoplankton Growth In the Oligotrophic Regionsmentioning

confidence: 65%

Section: Phytoplankton Growth In the Oligotrophic Regionsmentioning

confidence: 91%

Section: Microplankton Stock Measurementsmentioning

confidence: 99%

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Basin-scale variability of phytoplankton biomass, production and growth in the Atlantic Ocean

Marañón

Holligan

Varela

et al. 2000

Deep Sea Research Part I: Oceanographic Research Papers

197

157

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“…However, more information is needed on the largescale distribution of size-fractionated phytoplankton biomass and carbon fixation in order to improve our knowledge of the dynamics of open ocean ecosystems. In this context, although picophytoplankton abundance and spatial distribution has been described previously within the tropical Atlantic (Zubkov et al, 1998;Tarran et al, 2006), few studies have combined such measurements with size-fractionated primary production determinations (i.e. Marañón et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Moreno-Ostos¹,

Fernández²,

Huete-Ortega³

et al. 2010

Sci. Mar.

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SUMMARY: Two meridional transects were conducted in the tropical and subtropical Atlantic to describe (i) the spatial variability of total and size-fractionated (picophytoplankton and phytoplankton >2 mm) chlorophyll a (chl a) concentration and primary production, (ii) the relative contribution of each phytoplankton size fraction to total biomass and carbon fixation, and (iii) the spatial variability of size-fractionated phytoplankton growth rate (P/B) and assimilation number (P/chl a) in the ocean. The highest chl a for both size fractions was observed in the Western Tropical Atlantic province (WTRA), while the lowest chl a was found in the upper mixed layer (UML) of the South Atlantic Tropical gyre (SATL). A similar pattern was found for carbon fixation. Within the SATL, the highest picophytoplankton contribution to total production was recorded at the Deep Chlorophyll Maximum (DCM), while the contribution of phytoplankton >2 mm was higher in the UML. Additionally, the relative contribution of large phytoplankton to total integrated primary production was higher than its contribution to total biomass. Both size fractions depicted maximum P/B and P/chl a in WTRA surface waters. In the SATL province, phytoplankton >2 mm showed the highest P/B and P/chl a along the UML, while picophytoplankton P/B and P/chl a peaked around the DCM. We suggest that the differential impact of light on small and large phytoplankton may help to explain the contrasting dynamics of the two size classes.Keywords: phytoplankton, cell size, spatial variability, oligotrophic subtropical gyres, primary production, biomass.RESUMEN: Biomasa y producción en diferentes clases de tamaño de fitoplancton en el Atlántico tropical.-Se realizaron dos transectos latitudinales en el Atlántico tropical y subtropical para describir (i) la variabilidad espacial de la concentración de clorofila a (chl a) y de la producción primaria total y fraccionada en clases de tamaño de fitoplancton (picofitoplancton y fitoplancton >2 mm), (ii) la contribución relativa de cada clase de tamaño a la biomasa y fijación de carbono total, y (iii) la variabilidad espacial de la tasa de crecimiento (P/B) y del número de asimilación (P/chl a) para cada clase de tamaño en el océano. Las dos clases de tamaño consideradas presentaron la máxima chl a en el afloramiento ecuatorial y la mínima en la capa de mezcla del giro oligotrófico del Atlántico Sur. Se encontró un patrón similar en el caso de la fijación de carbono. En el giro oligotrófico del Atlántico Sur la mayor contribución del picofitoplancton a la producción total se registró en torno al máximo profundo de clorofila, mientras que la contribución de la fracción >2 mm fue mayor en la capa de mezcla. Además, la contribución relativa del fitoplancton >2 mm a la producción primaria total fue mayor que su contribución a la biomasa total. Ambas clases de tamaño presentaron máximos valores de P/B y P/chl a en las aguas superficiales del afloramiento ecuatorial. En el giro oligotrófico del Atlántico Sur la fracción de fitoplancto...

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“…Size determinations of the various groups of phytoplankton (picoeukaryotes, Synechococcus sp. and small and large nanophytoplankton) were performed by filtering parallel samples through 0.8, 1, 2, 5 and 10 µm polycarbonate filters and counting the filtrate, thereby enumerating the percentage of each group within the given size interval, a method modified from Zubkov et al (1998).…”

Section: Size and Biomass Estimation Of Protistsmentioning

confidence: 99%

Winter-spring transition in the subarctic Atlantic: microbial response to deep mixing and pre-bloom production

Paulsen¹,

Riisgaard²,

Thingstad³

et al. 2015

Aquat. Microb. Ecol.

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In temperate, subpolar and polar marine systems, the classical perception is that diatoms initiate the spring bloom and thereby mark the beginning of the productive season. Contrary to this view, we document an active microbial food web dominated by pico-and nanoplankton prior to the diatom bloom, a period with excess nutrients and deep convection of the water column. During repeated visits to stations in the deep Iceland and Norwegian basins and the shallow Shetland Shelf (26 March to 29 April 2012), we investigated the succession and dynamics of photosynthetic and heterotrophic microorganisms. We observed that the early phytoplankton production was followed by a decrease in the carbon:nitrogen ratio of the dissolved organic matter in the deep mixed stations, an increase in heterotrophic prokaryote (bacteria) abundance and activity (indicated by the high nucleic acid:low nucleic acid bacteria ratio), and an increase in abundance and size of heterotrophic protists. The major chl a contribution in the early winter−spring transition was found in the fraction <10 µm, i.e. dominated by pico-and small nanophytoplankton. The relative abundance of picophytoplankton decreased towards the end of the cruise at all stations despite nutrient-replete conditions and increasing day length. This decrease is hypothesised to be the result of top-down control by the fast-growing population of heterotrophic protists. As a result, the subsequent succession and nutrient depletion can be left to larger phytoplankton resistant to small grazers. Further, we observed that large phytoplankton (chl a > 50 µm) were stimulated by deep mixing later in the period, while picophytoplankton were unaffected by mixing; both physical and biological reasons for this development are discussed herein.

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Picoplanktonic community structure on an Atlantic transect from 50°N to 50°S

Cited by 265 publications

References 39 publications

Basin-scale variability of phytoplankton biomass, production and growth in the Atlantic Ocean

Basin-scale variability of phytoplankton biomass, production and growth in the Atlantic Ocean

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Winter-spring transition in the subarctic Atlantic: microbial response to deep mixing and pre-bloom production

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