Production and particle characterization of the frustules of Cyclotella cryptica in comparison with siliceous earth

Csögör, Zsuzsa; Melgar, Dyna; Schmidt, Karsten; Posten, Clemens

doi:10.1016/s0168-1656(99)00060-7

Cited by 15 publications

(7 citation statements)

References 3 publications

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“…Diatom frustules are 10% to 70% amorphous silica (density < 2600 kg m 23 ), the rest of the frustule being composed of proteins and sugars (density < 1300 kg m 23 [Schmid et al 1981;Csoegoer et al 1999]). This gives a range of frustule density, r fr , from 1400 kg m 23 to 2200 kg m 23 .…”

Section: Methodsmentioning

confidence: 99%

“…Frustule density and thickness-As mentioned earlier, the frustule is between 10% and 70% silica; the remainder consists of organic components (Schmid et al 1981;Swift and Wheeler 1992). This indicates that frustule density may occupy a relatively large range of values, though little effort has been made to directly measure frustule density (for an exception, see Csoegoer et al 1999). Instead, most work has focused on silica content (the mass of silica per cell) and how it varies with size and with environmental conditions such as temperature, salinity, light, and nutrient conditions (for a review, see Martin-Jezequel et al 2000).…”

Section: ! ð22þmentioning

confidence: 99%

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Diatom sinkings speeds: Improved predictions and insight from a modified Stokes' law

Miklasz

Denny

2010

Limnology & Oceanography

124

101

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Accurately predicting the size-dependant sinking rate of diatoms is necessary to fully understand the cycling of oceanic carbon and silicon. Stokes' law predicts that sinking velocity should be proportional to the square of a diatom's radius (a scaling exponent of 2), which does not agree with empirically measured sinking speeds (scaling exponents of 1.2-1.6). We offer an alternative model for sinking speed that separately accounts for the different densities of a diatom's frustule (its siliceous cell armor) and its cytoplasm. The ratio of frustule to cytoplasm volume changes with size and, thereby, affects the scaling relationship between velocity and radius. The resulting model predicts a scaling exponent between 1 and 2 depending on the size and shape of the diatom, more accurately predicting the upper bound of measured sinking speeds and offering an analytical formula for the prediction of the maximum sinking speed of diatoms.

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Section: Methodsmentioning

confidence: 99%

Section: ! ð22þmentioning

confidence: 99%

Diatom sinkings speeds: Improved predictions and insight from a modified Stokes' law

Miklasz

Denny

2010

Limnology & Oceanography

124

101

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“…In turn, coccolithophores and foraminifera tests reveal densities of only 1.55 g cm −3 (Winter and Siesser, 1994) and up to 1.7 g cm −3 (Schiebel et al, 2007;Schiebel and Hemleben, 2000). In contrast to opal, which is a hydrous silicon oxide with a density between 1.9 and 2.5 g cm −3 , the density of diatom frustules (biogenic opal) varies between 1.46 and 2.0 g cm −3 (Csögör et al, 1999;DeMaster, 2003).…”

Section: Sinking Speedmentioning

confidence: 98%

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

Rixen

Gaye²,

Emeis

et al. 2019

Biogeosciences

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Data obtained from long-term sediment trap experiments in the Indian Ocean in conjunction with satellite observations illustrate the influence of primary production and the ballast effect on organic carbon flux into the deep sea. They suggest that primary production is the main control on the spatial variability of organic carbon fluxes at most of our study sites in the Indian Ocean, except at sites influenced by river discharges. At these sites the spatial variability of organic carbon flux is influenced by lithogenic matter content. To quantify the impact of lithogenic matter on the organic carbon flux, the densities of the main ballast minerals, their flux rates and seawater properties were used to calculate sinking speeds of material intercepted by sediment traps. Sinking speeds in combination with satellite-derived export production rates allowed us to compute organic carbon fluxes. Flux calculations imply that lithogenic matter ballast increases organic carbon fluxes at all sampling sites in the Indian Ocean by enhancing sinking speeds and reducing the time of organic matter respiration in the water column. We calculated that lithogenic matter content in aggregates and pellets enhances organic carbon flux rates on average by 45 % and by up to 62 % at trap locations in the river-influenced regions of the Indian Ocean. Such a strong lithogenic matter ballast effect explains the fact that organic carbon fluxes are higher in the low-productive southern Java Sea compared to the high-productive western Arabian Sea. It also implies that land use changes and the associated enhanced transport of lithogenic matter from land into the ocean may significantly affect the CO 2 uptake of the organic carbon pump in the receiving ocean areas.

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“…In turn, coccolithophores and foraminifera tests reveal densities of only 1.55 g cm -3 (page 71, Winter and Siesser, 1994) and up to 1.7 g cm -3 (Schiebel et al, 2007;Schiebel and Hemleben, 2000). In contrast to opal -which is a hydrous silicon oxide and reveals densities of 1.9 to 2.5 g cm -3 -the 20 density of diatom frustules (biogenic opal) varies between 1.46 and 2.0 g cm -3 (Csögör et al, 1999;DeMaster, 2003).…”

Section: Sinking Speeds 10mentioning

confidence: 99%

The Ballast Effect of Lithogenic Matter and its Influences on the Carbon Fluxes in the Indian Ocean

Rixen¹,

Gaye²,

Emeis³

et al. 2018

Preprint

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Abstract. Data obtained from long-term sediment trap experiments in the Indian Ocean were analysed in conjunction with 10 satellite-derived observations and results obtained from a box model to study the influence of primary production and the ballast effect on organic carbon flux into the deep sea. The results are used to better understand the associated impacts on the CO 2 uptake of the organic carbon pump. In line with other findings derived from global data sets, our results suggest that a preferential export of organic matter in slower-sinking particles reduces the transfer efficiency of exported organic matter in high-productive systems compared with low-productive regions. The resulting enhanced respiration of organic matter 15 maintains the high nutrient availability in the surface ocean and thus the high productivity during the summer and winter bloom in the Arabian Sea. In turn, mineral ballast is essential for the transport of organic matter and nutrients into the deep sea. The additional lithogenic ballast effect can increase organic carbon fluxes by 60 %. Our model results indicate that lithogenic ballast enhances the CO 2 uptake of the organic carbon pump by increasing the amount of nutrients utilised by the organic carbon pump to bind CO 2 . By enhancing the export of organic matter into the deep sea, the ballast effect increases 20 the residence time of these nutrients in the ocean. They lose the attached CO 2 if they are introduced into the surface ocean at higher latitude, where the lack of light prevents photosynthesis in winter. Considering the impact of the lithogenic ballast effect on the organic carbon export into the deep sea and the enhanced mobilisation of lithogenic matter due to land-use changes, it is assumed that humans influence the CO 2 uptake of the organic carbon pump, which might hold relevance for the discussion about the anthropogenic CO 2 uptake of the ocean. 25

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Production and particle characterization of the frustules of Cyclotella cryptica in comparison with siliceous earth

Cited by 15 publications

References 3 publications

Diatom sinkings speeds: Improved predictions and insight from a modified Stokes' law

Diatom sinkings speeds: Improved predictions and insight from a modified Stokes' law

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

The Ballast Effect of Lithogenic Matter and its Influences on the Carbon Fluxes in the Indian Ocean

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