Global verification of critical depth theory for phytoplankton bloom with climatological in situ temperature and satellite ocean color data

Obata, Atsushi; Ishizaka, Joji; Endoh, Masahiro

doi:10.1029/96jc01734

Cited by 139 publications

(68 citation statements)

References 20 publications

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“…7; cf. Obata et al, 1996, for seasonal changes in the surface ocean productivity) between 1989 and 1999 (Fig. 2), the average PFAB > 125 µm test-size sums up to a global average of 2.93-11.27 mg C m −2 (geometric mean and arithmetic mean, respectively) at any point of time (Table 4: 2934.11-11265.13 µg C m −2 ).…”

Section: First-order Estimates Of the Global Planktic Foraminifer Biomentioning

confidence: 99%

First-order estimate of the planktic foraminifer biomass in the modern ocean

Schiebel

Movellan

2012

Earth Syst. Sci. Data

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Abstract. Planktic foraminifera are heterotrophic mesozooplankton of global marine abundance. The position of planktic foraminifers in the marine food web is different compared to other protozoans and ranges above the base of heterotrophic consumers. Being secondary producers with an omnivorous diet, which ranges from algae to small metazoans, planktic foraminifers are not limited to a single food source, and are assumed to occur at a balanced abundance displaying the overall marine biological productivity at a regional scale. With a new non-destructive protocol developed from the bicinchoninic acid (BCA) method and nano-photospectrometry, we have analysed the protein-biomass, along with test size and weight, of 754 individual planktic foraminifers from 21 different species and morphotypes. From additional CHN analysis, it can be assumed that proteinbiomass equals carbon-biomass. Accordingly, the average individual planktic foraminifer protein-and carbonbiomass amounts to 0.845 µg. Samples include symbiont bearing and symbiont-barren species from the sea surface down to 2500 m water depth. Conversion factors between individual biomass and assemblage-biomass are calculated for test sizes between 72 and 845 µm (minimum test diameter). Assemblage-biomass data presented here include 1128 sites and water depth intervals. The regional coverage of data includes the North Atlantic, Arabian Sea, Red Sea, and Caribbean as well as literature data from the eastern and western North Pacific, and covers a wide range of oligotrophic to eutrophic waters over six orders of magnitude of plankticforaminifer assemblage-biomass (PFAB). A first order estimate of the average global planktic foraminifer biomass production (> 125 µm) ranges from 8.2-32.7 Tg C yr −1 (i.e. 0.008-0.033 Gt C yr −1 ), and might be more than three times as high including neanic and juvenile individuals adding up to 25-100 Tg C yr −1 . However, this is a first estimate of regional PFAB extrapolated to the global scale, and future estimates based on larger data sets might considerably deviate from the one presented here. This paper is supported by, and a contribution to the Marine Ecosystem Data project (MAREDAT).

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Section: First-order Estimates Of the Global Planktic Foraminifer Biomentioning

confidence: 99%

First-order estimate of the planktic foraminifer biomass in the modern ocean

Schiebel

Movellan

2012

Earth Syst. Sci. Data

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“…A common paradigm in aquatic ecology and oceanography is that phytoplankton blooms can develop only if the upper mixed-water layer is shallower than some critical depth (e.g., Sverdrup 1953;Smetacek and Passow 1990;Nelson and Smith 1991;Platt et al 1991;Kirk 1994;Mann and Lazier 1996;Obata et al 1996;Falkowski and Raven 1997). The idea is that once the upper water column is sufficiently shallow, the light conditions will be favorable for photosynthesis, so that depth-integrated photosynthesis exceeds the depth-integrated losses of the phytoplankton.…”

Section: Notesmentioning

confidence: 99%

Critical depth and critical turbulence: Two different mechanisms for the development of phytoplankton blooms

Huisman

Oostveen

Weissing

1999

Limnology & Oceanography

435

355

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A turbulent diffusion model shows that there are two different mechanisms for the development of phytoplankton blooms. One of these mechanisms works in well‐mixed environments and corresponds to the classical critical depth theory. The other mechanism is based on the rate of turbulent mixing. If turbulent mixing is less than a critical turbulence, phytoplankton growth rates exceed the vertical mixing rates, and a bloom develops irrespective of the depth of the upper water layer. These results demonstrate that phytoplankton blooms can develop in the absence of vertical water‐column stratification.

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“…If the absolute density difference in UQHL ds q = js q (z D ) À s qw j is less than a specific ds q , then h D is associated with the mixed layer depth MLD [Brainerd and Gregg, 1995]. Calculating ILD, Thompson [1976] and Martin [1985] employed relatively small dT = 0.2°C and 0.1°C, respectively, and a larger dT = 0.5°C have been used by Price et al [1986], Kelly and Qiu [1995], Obata et al [1996], and Monterey and Levitus [1997]. Lamb [1984], Wagner [1996], and Qu [2003] increased dT up to 1°C.…”

Section: Appendix B: Calculation Of the Mixed Layer Depthmentioning

confidence: 99%

Observations and scaling of the upper mixed layer in the North Atlantic

et al. 2005

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[1] The dependence of the mixed layer depth h D on the sea surface fluxes is analyzed based on measurements taken along a cross-Atlantic section 53°N. A linear function h D % 0.44L f , where L f = u * /f is the Ekman scale, well represents the influence of the wind stress u * and rotation f on the mixed-layer deepening, thus indicating that the influence of convective mixing in late spring at this latitude is of a lesser importance. Also, data showed reasonable correlation of h D with the stratified Ekman scale L fN = u * / ffiffiffiffiffiffiffiffi fN pc p , where N pc is the buoyancy frequency in the pycnocline, according to h D % 1.9L fN . In both cases the highest correlation between h D and the corresponding lengthscales is achieved when u * values taken 12 hours in advance of the mixed layer measurements were used, which may signify the adjustment time of inertial oscillations to produce critical shear at the base of the mixed layer. The vertical profiles of the dissipation rate e(z) are parameterized by two formulae that are based on the law of the wall scaling e s (z) = u * 3 /0.4z and the buoyancy flux J b : e 1 (z) = 2.6e s (z) + 0.6J b and e 2 (z) = e s (z) e s (z) + 3.7J b . The first parameterization is used to calculate the integrated dissipationẽ int over the mixing layer, which was found to be $3-7% (5% on the average) of the wind work E 10 . The positive correlation between h D andẽ int /E 10 suggests that in deeper quasi-homogeneous layers a larger portion of the wind work is consumed by viscous dissipation vis-à-vis that is used for entrainment. As such, the mixing efficiency, which is based on integral quantities, is expected to decrease with the growth of the mixed layer.

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Global verification of critical depth theory for phytoplankton bloom with climatological in situ temperature and satellite ocean color data

Cited by 139 publications

References 20 publications

First-order estimate of the planktic foraminifer biomass in the modern ocean

First-order estimate of the planktic foraminifer biomass in the modern ocean

Critical depth and critical turbulence: Two different mechanisms for the development of phytoplankton blooms

Observations and scaling of the upper mixed layer in the North Atlantic

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