Mesoscale vertical motion and the size structure of phytoplankton in the ocean

Rodrı́guez, Jaime; Tintoré, Joaquín; Allen, John T.; Blanco, José Ma; Gomis, Damià; Reul, Andreas; Ruiz, Javier; Rodrı́guez, Valeriano; Echevarrı́a, Fidel; Jiménez‐Gómez, Francisco

doi:10.1038/35066560

Cited by 205 publications

(147 citation statements)

References 20 publications

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“…These observations can be linked to the influence of the NAO through the North Atlantic basin, as Drinkwater et al (2003) have shown that the physical response to NAO forcing varies spatially across the North Atlantic. Furthermore, the main factors likely to affect phytoplankton dynamics and community structure (besides light, temperature, and salinity) are turbulence and the related nutrient supply (Rodriguez et al 2001;Li 2002).…”

Section: Discussionmentioning

confidence: 99%

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

et al. 2005

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The Continuous Plankton Recorder (CPR) survey has been used to characterize phytoplankton and zooplankton space-time dynamics in the North Sea since 1931 and in the North Atlantic since 1939. Phytoplankton biomass is assessed from these samples by visual assessment of the green color of the silk mesh, the Phytoplankton Color Index (PCI), and the total count of diatoms and dinoflagellates. Species with a frequency of occurrence greater than 1% in the samples are used as indicator species of the community. We investigated (1) long-term fluctuations of phytoplankton biomass, total diatoms, and total dinoflagellates; (2) geographical variation of patterns; (3) the relationship between phytoplankton and climate forcing in the North Atlantic CPR samples; (4) the relative contribution of diatoms and dinoflagellates to the PCI; and (5) the fluctuations of the dominant species over the period of survey to provide more information on the processes linking climate to changes in the phytoplankton community. As a result of the differences in microscopic analysis methods prior to 1958, our analyses were conducted for the period ranging from 1958 to 2002. The North Atlantic was divided into six regions identified through bathymetric criteria and separated along a North-South axis. Based on 12 monthly time series, we demonstrate increasing trends in PCI and total dinoflagellates and a decrease in total diatoms.

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Section: Discussionmentioning

confidence: 99%

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

et al. 2005

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“…4c). During this period, the GPP:CR ratio varied drastically from net heterotrophic (0.22) to net autotrophic (2.8) ( Table 2) It is recognized that mesoscale vertical motion directly controls the phytoplankton size structure in the ocean (Rodríguez et al 2001). In northern Chile, changes in the size-fractionated primary production and biomass have been observed during interannual atmospheric forcing , as reflected by the dominance of pico-and nanophytoplankton (> 50%) and low primary production rates (González et al 1998, Iriarte et al 2000, Iriarte & González 2004.…”

Section: Oceanographic Variability and Biological Responsementioning

confidence: 99%

Community metabolism, phytoplankton size structure and heterotrophic prokaryote production in a highly productive upwelling zone off northern Chile

Jacob¹,

Daneri²,

Quiñones³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…When this is not the case, fluid dynamics at scales larger than those associated with isotropic turbulence must have a relevant role in maintaining phytoplankton in the photic zone. For instance, upward flows associated with mesoscale events can balance the sinking of larger and heavier cells (25). In the absence of these events, compensatory physiological mechanisms, such as those described for diatoms that are able to decrease their density when in unlit waters (26), may partly facilitate the use of deep-water nutrients (27) and also help avoid the population sinking in an environment where turbulence is unable to prevent settling if cells are denser than water.…”

Section: The Mean Velocity (W) Obtained With the Intelligent Camera Formentioning

confidence: 99%

Turbulence increases the average settling velocity of phytoplankton cells

Ruiz

Macías²,

Peters³

2004

Proc. Natl. Acad. Sci. U.S.A.

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It is a well known fact that stirring keeps particles suspended in fluids. This is apparent, for instance, when shaking medicine flasks, when agitating tea deposits in a mug, or when heavy winds fill the air with dust particles. The commonplace nature of such observations makes it easy to accept that this feature will apply to any natural phenomenon as long as the flow is turbulent enough. This has been the case for phytoplankton in the surface mixed layers of lakes and oceans. The traditional view assumes that an increase in turbulence bears ecological advantages for nonmotile groups like diatoms that, otherwise, would settle in deep and unlit waters. However, this assumption has no theoretical ground, and the experimental results we present here point in the opposite direction. Phytoplankton settling velocity increases when turbulence intensifies from the low to the higher values recorded in the upper mixed layers of lakes and oceans. Consequently, turbulence does not favor phytoplankton remaining in lit waters but is rather an environmental stress that can only be avoided through morphological and͞or physiological adaptations. P hytoplankton in the upper mixed layers of lakes and oceans live in a turbulent flow regime. This circumstance may shape many features of their physiological and morphological functioning including the efficiency of nutrient assimilation (1), prey-predator interactions (2) and cell division (3). One of the key controls turbulence exerts on phytoplankton results from its effect on sedimentation rates. A compensatory role is usually assumed for turbulence, especially for nonmotile cells lacking other mechanisms to counteract their sinking from the surface to depth. However, this potential role cannot result from a direct effect of turbulence on the settling velocity of cells. The results presented in this paper clearly demonstrate that turbulence increases the settling of phytoplankton cells, regardless of the species considered and independent of turbulence-generation devices or velocity-measurement instruments. Our evidence questions the traditionally accepted notion that turbulence diminishes phytoplankton settling in the ocean. All experiments were made with particle concentrations Ͻ20 ppm by volume, with negligible effects on the flow. It is also a low concentration to expect significant deviations from Stokes terminal velocity due to interactions between the fields generated by two falling particles (4). These deviations scale as the ratio of particle diameter to distance between particles (4). The value of the latter can be estimated as the inverse cube root of the particle concentration (Ͻ20 ppm by volume) divided by individual volume (function of particle ESD). Ratios of ESD to distance between particle of the order of 0.01 are obtained. Deviations from Stokes terminal velocities observed in our experiments are much higher (see below). Therefore, interaction between particles cannot be the exclusive origin of the results presented below. On the other hand, temperature variations...

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Mesoscale vertical motion and the size structure of phytoplankton in the ocean

Cited by 205 publications

References 20 publications

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

Community metabolism, phytoplankton size structure and heterotrophic prokaryote production in a highly productive upwelling zone off northern Chile

Turbulence increases the average settling velocity of phytoplankton cells

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Mesoscale vertical motion and the size structure of phytoplankton in the ocean

Cited by 205 publications

References 20 publications

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

Decadal basin-scale changes in diatoms, dinoflagellates, and phytoplankton color across the North Atlantic

Community metabolism, phytoplankton size ­structure and heterotrophic prokaryote production in a highly productive upwelling zone off northern Chile

Turbulence increases the average settling velocity of phytoplankton cells

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Community metabolism, phytoplankton size structure and heterotrophic prokaryote production in a highly productive upwelling zone off northern Chile