The Atlantic Meridional Transect (AMT) Programme: A contextual view 1995–2005

Robinson, Carol; Poulton, Alex J.; Holligan, P. M.; Baker, AR; Forster, G.; Gist, Niki; Jickells, TD; Malin, Gill; Upstill‐Goddard, Robert C.; Williams, Richard G.; Woodward, E. Malcolm S.; Zubkov, Mikhail V.

doi:10.1016/j.dsr2.2006.05.015

Cited by 97 publications

(76 citation statements)

References 128 publications

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“…Metagenomics and metatranscriptomics technology has now developed sufficiently to study how whole communities might respond to CO 2 perturbation (Gilbert et al, 2008). Some existing projects to sample long ocean transects, such as the Atlantic Meridional Transect (Robinson et al (2006), offer opportunities to test how the increasingly welldefined microbial assemblages in different ocean provinces (Schattenhofer et al, 2009) might vary with pH. Large-scale surveys and time-series efforts are also crucial for scaling up physiological and genomic studies to ecosystems, with the ultimate goal of understanding impacts on biogeochemical cycling and ecosystem services (Doney et al, 2004).…”

Section: Future Prioritiesmentioning

confidence: 99%

Will ocean acidification affect marine microbes?

2010

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The pH of the surface ocean is changing as a result of increases in atmospheric carbon dioxide (CO2), and there are concerns about potential impacts of lower pH and associated alterations in seawater carbonate chemistry on the biogeochemical processes in the ocean. However, it is important to place these changes within the context of pH in the present-day ocean, which is not constant; it varies systematically with season, depth and along productivity gradients. Yet this natural variability in pH has rarely been considered in assessments of the effect of ocean acidification on marine microbes. Surface pH can change as a consequence of microbial utilization and production of carbon dioxide, and to a lesser extent other microbially mediated processes such as nitrification. Useful comparisons can be made with microbes in other aquatic environments that readily accommodate very large and rapid pH change. For example, in many freshwater lakes, pH changes that are orders of magnitude greater than those projected for the twenty second century oceans can occur over periods of hours. Marine and freshwater assemblages have always experienced variable pH conditions. Therefore, an appropriate null hypothesis may be, until evidence is obtained to the contrary, that major biogeochemical processes in the oceans other than calcification will not be fundamentally different under future higher CO2/lower pH conditions.

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Section: Future Prioritiesmentioning

confidence: 99%

Will ocean acidification affect marine microbes?

2010

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“…To determine the concentration of dissolved reactive phosphate, water samples were collected and stored frozen at -20°C until analysed in the laboratory with the same segmented-flow automatic analyser, following standard colorimetric methods (Grasshoff, 1976). The nitracline was defined as the depth at which nitrate concentration reached 1 mmol L -1 (Robinson et al, 2006) and the phosphocline as the depth at which phosphate concentrations reached 0.2 mmol L -1 . We assumed that silicate was not a limiting factor for phytoplankton dynamics in the oligotrophic Atlantic.…”

Section: Nutrient Concentrationsmentioning

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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“…The AMT programme began in 1995, with the aims of quantifying the nature and causes of biogeochemical and ecological variability in plankton of the Atlantic Ocean, and assessing the effects of this variability on air-sea gas and aerosol exchange, and biological carbon cycling (Robinson et al, 2006). It was also used for the calibration and validation of measurements and products from the Sea-viewing Wide Field-ofview Sensor (SeaWiFS) (Hooker and McClain, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…The Atlantic Meridional Transect (AMT) Programme is a UK National Environmental Research Council (NERC) funded project consisting of a time-series of oceanographic stations along a 13,500 km north-south transect (50°N-50°S) in the Atlantic Ocean (Aiken et al, 2000;Robinson et al, 2006). The AMT programme began in 1995, with the aims of quantifying the nature and causes of biogeochemical and ecological variability in plankton of the Atlantic Ocean, and assessing the effects of this variability on air-sea gas and aerosol exchange, and biological carbon cycling (Robinson et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Temporal changes in total and size-fractioned chlorophyll-a in surface waters of three provinces in the Atlantic Ocean (September to November) between 2003 and 2010

Ağırbaş

Martinez‐Vicente

Brewin

et al. 2015

Journal of Marine Systems

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Phytoplankton total chlorophyll concentration (TCHLa) and phytoplankton size structure are two important ecological indicators in biological oceanography. Using high performance liquid chromatography (HPLC) pigment data, collected from surface waters along the Atlantic Meridional Transect (AMT), we examine temporal changes in TCHLa and phytoplankton size class (PSC: micro-, nano-and pico-phytoplankton) between 2003 and 2010 (September to November cruises only), in three ecological provinces of the Atlantic Ocean. The HPLC data indicate no significant change in TCHLa in northern and equatorial provinces, and an increase in the southern province. These changes were not significantly different to changes in TCHLa derived using satellite oceancolour data over the same study period. Despite no change in AMT TCHLa in northern and equatorial provinces, significant differences in PSC were observed, related to changes in key diagnostic pigments (fucoxanthin, peridinin, 19′-hexanoyloxyfucoxanthin and zeaxanthin), with an increase in small cells (nano-and picophytoplankton) and a decrease in larger cells (micro-phytoplankton). When fitting a three-component model of phytoplankton size structure -designed to quantify the relationship between PSC and TCHLa to each AMT cruise, model parameters varied over the study period. Changes in the relationship between PSC and TCHLa have wide implications in ecology and marine biogeochemistry, and provide key information for the development and use of empirical ocean-colour algorithms. Results illustrate the importance of maintaining a timeseries of in-situ observations in remote regions of the ocean, such as that acquired in the AMT programme.

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The Atlantic Meridional Transect (AMT) Programme: A contextual view 1995–2005

Cited by 97 publications

References 128 publications

Will ocean acidification affect marine microbes?

Will ocean acidification affect marine microbes?

Size-fractionated phytoplankton biomass and production in the tropical Atlantic

Temporal changes in total and size-fractioned chlorophyll-a in surface waters of three provinces in the Atlantic Ocean (September to November) between 2003 and 2010

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