Simple models of steady deep maxima in chlorophyll and biomass

Hodges, Benjamin A.; Rudnick, Daniel L.

doi:10.1016/j.dsr.2004.02.009

Cited by 72 publications

(51 citation statements)

References 21 publications

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“…5A) and advective processes that bring different water masses in contact, as proposed in classic papers (e.g. Cullen 1982) and confirmed by modeling simulations (Hodges andRudnick 2004, Huisman et al 2006).…”

Section: Applicability/limitations Of the Hypothesesmentioning

confidence: 79%

Turbulence as a driver for vertical plankton distribution in the subsurface upper ocean

Macías¹,

Rodríguez-Santana²,

Ramirez-Romero³

et al. 2013

Sci. Mar.

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SUMMARY: Vertical distributions of turbulent energy dissipation rates and fluorescence were measured simultaneously with a high-resolution micro-profiler in four different oceanographic regions, from temperate to polar and from coastal to open waters settings. High fluorescence values, forming a deep chlorophyll maximum (DCM), were often located in weakly stratified portions of the upper water column, just below layers with maximum levels of turbulent energy dissipation rate. In the vicinity of the DCM, a significant negative relationship between fluorescence and turbulent energy dissipation rate was found. We discuss the mechanisms that may explain the observed patterns of planktonic biomass distribution within the ocean mixed layer, including a vertically variable diffusion coefficient and the alteration of the cells' sinking velocity by turbulent motion. These findings provide further insight into the processes controlling the vertical distribution of the pelagic community and position of the DCM.Keywords: turbulence, deep chlorophyll maximum, vertical plankton distribution. RESUMEN: La turbulencia como mecanismo forzante de la distribución vertical del plancton en el océano subsuperficial. -Las distribuciones verticales de la tasa de disipación de la energía turbulenta y de la fluorescencia han sido medidas simultáneamente usando un microperfilador de alta resolución en cuatro regiones oceánicas distintas, desde zonas templadas a polares y desde regiones costeras al océano abierto. Valores altos de fluorescencia, conformando un máximo profundo de clorofila (MPC) fueron detectados habitualmente en regiones poco estratificadas de la columna de agua y justo por debajo de capas con valores máximos de la tasa de disipación de la energía turbulenta. En las cercanías del MPC se encontró una relación estadísticamente significativa y negativa entre los valores de fluorescencia y energía turbulenta. En este trabajo se discuten los posibles mecanismos que pueden explicar estas relaciones, incluyendo el efecto de la variación vertical del coeficiente de difusión y la posible alteración de la velocidad de sedimentación de las células de fitoplancton por el movimiento turbulento. Estos resultados proporcionan un mayor conocimiento sobre los procesos que controlan la distribución vertical de la comunidad pelágica y la posición de los MPC.Palabras clave: turbulencia, máximo profundo de clorofila, distribución vertical del plancton.

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Section: Applicability/limitations Of the Hypothesesmentioning

confidence: 79%

Turbulence as a driver for vertical plankton distribution in the subsurface upper ocean

Macías¹,

Rodríguez-Santana²,

Ramirez-Romero³

et al. 2013

Sci. Mar.

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“…Biomass profiles of this type can be considered to be in, or close to, a steady state (Hodges and Rudnick, 2004). From the dynamical perspective this approach is crude, but solutions with initial biomass are valid in situations when the biomass does not change significantly during the time course of 1 day.…”

Section: Biomass Specificationmentioning

confidence: 99%

Extended Formulations and Analytic Solutions for Watercolumn Production Integrals

Kovač

Platt

Antunović³

et al. 2017

Front. Mar. Sci.

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The effect of biomass dynamics on the estimation of watercolumn primary production is analyzed, by coupling a primary production model to a simple growth equation for phytoplankton. The production model is formulated with depth-and time-resolved biomass, and placed in the context of earlier models, with emphasis on the canonical solution for watercolumn production. A relation between the canonical solution and the general solution for the case of an arbitrary depth-dependent biomass profile was derived, together with an analytical solution for watercolumn production in case of a depth dependent biomass profile described with the shifted Gaussian function. The analysis was further extended to the case of a time-dependent, mixed-layer biomass, and two additional analytical solutions to this problem were derived, the first in case of increasing mixed-layer biomass and the second in case of declining biomass. The solutions were tested with Hawaii Ocean Time-series data. The canonical solution for mixed-layer production has proven to be a good model for this data set. The shifted Gaussian function was demonstrated to be an accurate model for the measured biomass profiles and the shifted Gaussian parameters extracted from the measured profiles were further used in the analytical solution for watercolumn production and results compared with data. The influence of time-dependent biomass on mixed-layer production was studied through analytical solutions. Re-examining the Critical Depth Hypothesis we derived an expression for the daily increase in mixed-layer biomass. Finally, the work was placed in a remote sensing context and the time-dependent model for biomass related to the remotely sensed-biomass.

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“…Dolan & Marrasé 1995, Klausmeier & Litchman 2001, Fennel & Boss 2003, Hodges & Rudnick 2004, Holm-Hansen & Hewes 2004, Huisman et al 2006, Beckmann & Hense 2007, Sharples et al 2007. Vertical decoupling of the SBM and SCM is not rare and has been ascribed to photoacclimation, whereby the ratio of chl a to carbon increases with depth to optimize light harvesting (Steele 1964, Kiefer et al 1976, Cullen 1982, Falkowski & Kiefer 1985, Fennel & Boss 2003.…”

Section: Prevalence Structure and Properties Of Subsurface Chlorophymentioning

confidence: 99%

Prevalence, structure and properties of subsurface chlorophyll maxima in Canadian Arctic waters

Martin

Tremblay²,

Gagnon³

et al. 2010

Mar. Ecol. Prog. Ser.

211

226

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Comprehensive investigations of the Canadian Arctic during late summer and early fall revealed the widespread occurrence of long-lived subsurface chlorophyll maxima (SCM) in seasonally ice-free waters. The vertical position of the SCM corresponded with the depth of the subsurface biomass maximum (SBM), at least in Baffin Bay, suggesting that SCM could be an important source of carbon for the food web. Most of these SCM were located well below the pycnocline in close association with the nitracline, implying that their vertical position was driven mainly by a shortage of inorganic nitrogen in the upper euphotic zone. The diversity of SCM configurations with respect to physical properties of the water column complicates the estimation of euphotic-zone chlorophyll and primary production from surface properties. High photosynthetic yields (F v /F m ) showed the phytoplankton to be photosynthetically competent and well acclimated to conditions of irradiance and nutrient supply near the surface and at the SCM. A well-defined primary nitrite maximum was associated with the SCM in the southwest Canadian Arctic, but not in the northeast where nitrite concentrations were highest much below the euphotic zone. This contrast is consistent with differences in vertical stratification, the light -dark cycle and, possibly, the physiological state and taxonomic composition of the phytoplankton community at the SCM. This study demonstrates that the SCM, once regarded as anecdotal due to under-sampling, are a dominant feature of the Arctic Ocean that should be considered in remote sensing studies and biogeochemical models.

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Simple models of steady deep maxima in chlorophyll and biomass

Cited by 72 publications

References 21 publications

Turbulence as a driver for vertical plankton distribution in the subsurface upper ocean

Turbulence as a driver for vertical plankton distribution in the subsurface upper ocean

Extended Formulations and Analytic Solutions for Watercolumn Production Integrals

Prevalence, structure and properties of subsurface chlorophyll maxima in Canadian Arctic waters

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