Vertical distribution of phytoplankton biomass, production and growth in the Atlantic subtropical gyres

Pérez, Valesca; Fernández, Emilio; Marañón, Emilio; Morán, Xosé Anxelu G.; Zubkov, Mikhail V.

doi:10.1016/j.dsr.2006.07.008

Cited by 104 publications

(93 citation statements)

References 62 publications

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“…Maximum P/B and chl a values for this phytoplankton size fraction were typically found in the UML. A study of in situ phytoplankton growth rate for different size classes in the two Atlantic subtropical gyres (Pérez et al, 2006) also found that picophytoplankton showed significantly higher growth rates in the DCM than in the UML, while the opposite occurred in the larger size fraction. Pérez et al (2006) suggested that picophytoplankton should perform better than larger cells in the DCM, where light is low but nutrient availability is higher than in the UML.…”

Section: Discussionmentioning

confidence: 99%

“…and 237 fg C mm -3 for picoeukaryotes. The biomass of phytoplankton larger than 2 mm was estimated from the size-fractionated chl a data using the C:chl a ratio calculated by Pérez et al (2006) for this phytoplankton size class from a large data set collected from 94 oligotrophic stations in the Atlantic Ocean: 186 mg C mg chl a -1 in the UML and 58 mg C mg chl a -1 in the DCM.…”

Section: Size-fractionated Phytoplankton Biomassmentioning

confidence: 99%

“…At each sampling station, vertical profiles of temperature, salinity and fluorescence were obtained from the surface to 300 m depth using a CTDSBE911 probe attached to a rosette sampler equipped with 24 Niskin bottles. The beginning of the thermocline was defined as the depth at which the thermal gradient was >0.1ºC m -1 (Pérez et al, 2006).…”

Section: Study Area and General Hydrographymentioning

confidence: 99%

“…Although many studies have focused on the sizefractionated chlorophyll a (chl a) and primary production in different marine environments (Tremblay and Legendre, 1994;Legendre and Rassoulzadegan, 1996), only a small fraction of the available size-fractionated phytoplankton information has been recorded from open ocean waters and over large spatial scales (Marañón et al, 2001;Pérez et al, 2006;Morán et al, 2004;Poulton et al, 2006). Marañón et al (2001) described the main patterns of size-fractionated chl a and carbon fixation in the Atlantic Ocean and showed a marked discrepancy between the relative contribution of picophytoplankton to total chl a and primary production, particularly in the oligotrophic gyres (see also Teira et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, it has been demonstrated that solar radiation induces considerable cell damage and mortality in the subtropical Atlantic (Llabrés and Agustí, 2006;Agustí and Llabrés, 2007), and Teira et al (2005) hypothesized that a considerable fraction of the picophytoplankton biomass should correspond to damaged and non-viable cells, thus resulting in discrepancies between their contribution to biomass and carbon fixation. Pérez et al (2006) characterized the vertical variability of phytoplankton biomass, size structure, production and growth in the Atlantic subtropical gyres. 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.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Size-fractionated Phytoplankton Biomassmentioning

confidence: 99%

Section: Study Area and General Hydrographymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Moreno-Ostos¹,

Fernández²,

Huete-Ortega³

et al. 2010

Sci. Mar.

Self Cite

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Chlorophyll a reconstruction from in situ measurements: 2. Marked carbon uptake decrease in the last century

et al. 2015

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A chlorophyll a hindcast in the Madeira Basin from 1871 to 2008 was used to analyze the long‐term variability in the oligotrophic, subtropical gyres in relation to the climate change of the last century. The deep chlorophyll maximum (DCM), as dominant pattern of the chlorophyll a field, showed a fast decrease in its strength in the 1940s. An absolute minimum was reached between 1967 and 1973 when no DCM established with a recovering to the end of the time series. Long‐term variability of the DCM was related to the North Atlantic Oscillation with a time delay of 9 years. The marked decrease in the 1940s was correlated to the drop of the solar radiation in transition from early brightening to global dimming. Caused by the influence of the solar radiation and maybe related to increasing global temperatures in the last century, the integrated chlorophyll a concentration decreased by about 0.7 mg m−2 in 2008 compared to 1871. The high‐resolved chlorophyll a hindcast allowed an estimation of the carbon uptake by the ocean due to primary production in the euphotic zone. A rough calculation over the area of the global subtropical oceans showed 700 megaton less carbon uptake in 2008.

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Nitrogen fixation in the eastern Atlantic reaches similar levels in the Southern and Northern Hemisphere

et al. 2017

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Euphotic layer dinitrogen (N2) fixation and primary production (PP) were measured in the eastern Atlantic Ocean (38°N–21°S) using 15N2 and 13C bicarbonate tracer incubations. This region is influenced by Saharan dust deposition and waters with low nitrogen to phosphorus (N/P) ratios originating from the Subantarctic and the Benguela upwelling system. Depth‐integrated rates of N2 fixation in the north (0°N–38°N) ranged from 59 to 370 µmol N m−2 d−1, with the maximal value at 19°N under the influence of the northwest African upwelling. Diazotrophic activity in the south (0°S–21°S), though slightly lower, was surprisingly close to observations in the north, with values ranging from 47 to 119 µmol N m−2 d−1. Our North Atlantic N2 fixation rates correlate well with dust deposition, while those in the South Atlantic correlate strongly with excess phosphate relative to nitrate. There, the necessary iron is assumed to be supplied from the Benguela upwelling system. When converting N2 fixation to carbon uptake using a Redfield ratio (6.6), we find that N2 fixation may support up to 9% of PP in the subtropical North Atlantic (20°N–38°N), 5% in the tropical North Atlantic (0°N–20°N), and 1% of PP in the South Atlantic (0°S–21°S). Combining our data with published data sets, we estimate an annual N input of 27.6 ± 10 Tg N yr−1 over the open Atlantic Ocean, 11% of which enters the region between 20°N and 50°N, 71% between 20°N and 10°S, and 18% between 10°N and 45°S.

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Vertical distribution of phytoplankton biomass, production and growth in the Atlantic subtropical gyres

Cited by 104 publications

References 62 publications

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Chlorophyll a reconstruction from in situ measurements: 2. Marked carbon uptake decrease in the last century

Nitrogen fixation in the eastern Atlantic reaches similar levels in the Southern and Northern Hemisphere

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