Modeled Chl:C ratio and derived estimates of phytoplankton carbon biomass and its contribution to total particulate organic carbon in the global surface ocean

Abstract. Correlation between particulate organic carbon (POC) and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foraminferan-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the roller tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast- different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.

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Reconciling surface ocean productivity, export fluxes and sediment composition in a global biogeochemical ocean model

Biogeosciences Discussions ◽

10.5194/bgd-3-803-2006 ◽

2006 ◽

Vol 3 (3) ◽

pp. 803-836 ◽

Cited By ~ 3

Author(s):

M. Gehlen ◽

L. Bopp ◽

N. Emprin ◽

O. Aumont ◽

C. Heinze ◽

...

Keyword(s):

Particle Size ◽

Organic Carbon ◽

Particulate Organic Carbon ◽

Carbon Fluxes ◽

Ocean Model ◽

Size Spectrum ◽

Water Interface ◽

Standard Version ◽

Surface Ocean ◽

Organic Carbon Fluxes

Abstract. This study focuses on an improved representation of the biological soft tissue pump in the global three-dimensional biogeochemical ocean model PISCES. We compare three parameterizations of particle dynamics: (1) the model standard version including two particle size classes, aggregation-disaggregation and prescribed sinking speed; (2) an aggregation-disaggregation model with a particle size spectrum and prognostic sinking speed; (3) a mineral ballast parameterization with no size classes, but prognostic sinking speed. In addition, the model includes a description of surface sediments and organic carbon early diagenesis. The integrated representation of material fluxes from the productive surface ocean down to the sediment-water interface allows taking advantage of surface ocean observations, sediment trap data and exchange fluxes at the sediment-water interface. The capability of the model to reproduce yearly averaged particulate organic carbon fluxes and benthic oxygen demand does at first order not dependent on the resolution of the particle size spectrum. Model results obtained with the standard version and with the one including a particle size spectrum and prognostic sinking speed are not significantly different. Both model versions overestimate particulate organic carbon between 1000 and 2000 m, while deep fluxes are of the correct order of magnitude. Predicted benthic oxygen fluxes correspond with respect to their large scale distribution and magnitude to data based estimates. Modeled particulate organic C fluxes across the mesopelagos are most sensitive to the intensity of zooplankton flux feeding. An increase of the intensity of flux feeding in the standard version results in lower mid- and deep-water particulate organic carbon fluxes, shifting model results to an underestimation of particulate organic carbon fluxes in the deep. The corresponding benthic oxygen fluxes are too low. The model version including the mineral ballast parameterization yields an improved fit between modeled and observed particulate organic carbon fluxes below 2000 m and down to the sediment-water interface. Our results suggest that aggregate formation alone might not be sufficient to drive an intense biological pump. The later is most likely driven by the combined effect of aggregate formation and mineral ballasting.

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Not all calcite ballast is created equal: differing effects of foraminiferan and coccolith calcite on the formation and sinking of aggregates

Biogeosciences ◽

10.5194/bg-11-135-2014 ◽

2014 ◽

Vol 11 (1) ◽

pp. 135-145 ◽

Cited By ~ 15

Author(s):

K. Schmidt ◽

C. L. De La Rocha ◽

M. Gallinari ◽

G. Cortese

Keyword(s):

Calcium Carbonate ◽

Organic Carbon ◽

Particulate Organic Carbon ◽

Deep Ocean ◽

Simple Experiment ◽

Surface Ocean

Abstract. Correlation between particulate organic carbon (POC) and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foram-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the rolling tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast – different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.

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Review of “Decoupling of net community production and particulate organic carbon dynamics in near shore surface ocean waters” by Rosengard et al.

10.5194/bg-2019-257-rc1 ◽

2019 ◽

Author(s):

Anonymous

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Carbon Dynamics ◽

Net Community Production ◽

Surface Ocean ◽

Near Shore ◽

Community Production

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Blue carbon: past, present and future, with emphasis on macroalgae

Biology Letters ◽

10.1098/rsbl.2018.0336 ◽

2018 ◽

Vol 14 (10) ◽

pp. 20180336 ◽

Cited By ~ 3

Author(s):

John Raven

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Net Primary Productivity ◽

Great Majority ◽

Temperature Limit ◽

Blue Carbon ◽

Marine Macroalgae ◽

Tidal Marshes ◽

Surface Ocean ◽

Subsequent Storage

Blue carbon did not originally include macroalgal ecosystems; however evidence is mounting that macroalgal ecosystems function in marine carbon sequestration. The great majority of present day marine macroalgal net primary productivity (NPP) involves haptophytic algae on eroding shores. For these organisms the long-term storage of particulate organic carbon involves export from the site of production of biomass that has evaded parasites and grazers, and that some of the exported biomass is sedimented and stored rather than being mineralized en route by detritivores (microbes and fauna). Export from eroding shores, and subsequent storage, of haptophytic marine macroalgal particulate organic carbon could have started by 1.6 Ga. Storage on depositing shores close to the site of NPP by rhizophytic macroalgae and then by rhizophytic coastal seagrasses, tidal marshes and mangroves began not less than 209 Ma ago. Future increases in surface ocean temperatures may bring tropical marine macroalgae to their upper temperature limit, while temperate marine macroalgae will migrate poleward, in both cases assuming that temperature increases faster than genetic adaptation to higher temperature. Increased CO 2 in the surface ocean will generally favour uncalcified over calcified marine macroalgae. This results in decreased CO 2 release from decreased calcification, as well as decreased ballasting by CaCO 3 of exported particulate organic carbon resulting in decreasing sedimentation. While much more work is needed, the available information suggests that macroalgae play a significant role in marine organic carbon storage.

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Biominerals and the vertical flux of particulate organic carbon from the surface ocean

Geophysical Research Letters ◽

10.1029/2010gl044640 ◽

2010 ◽

Vol 37 (22) ◽

pp. n/a-n/a ◽

Cited By ~ 23

Author(s):

W. M. Balch ◽

B. C. Bowler ◽

D. T. Drapeau ◽

A. J. Poulton ◽

P. M. Holligan

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Vertical Flux ◽

Surface Ocean

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Supplementary material to "Decoupling of net community production and particulate organic carbon dynamics in near shore surface ocean waters"

10.5194/bg-2019-257-supplement ◽

2019 ◽

Author(s):

Sarah Z. Rosengard ◽

Robert W. Izett ◽

William J. Burt ◽

Nina Schuback ◽

Philippe D. Tortell

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Carbon Dynamics ◽

Net Community Production ◽

Surface Ocean ◽

Near Shore ◽

Supplementary Material ◽

Community Production

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Contribution of picoplankton to the total particulate organic carbon (POC) concentration in the eastern South Pacific

Biogeosciences Discussions ◽

10.5194/bgd-4-1461-2007 ◽

2007 ◽

Vol 4 (3) ◽

pp. 1461-1497 ◽

Cited By ~ 12

Author(s):

C. Grob ◽

O. Ulloa ◽

H. Claustre ◽

Y. Huot ◽

G. Alarcón ◽

...

Keyword(s):

Organic Carbon ◽

Spatial Variability ◽

Particulate Organic Carbon ◽

Attenuation Coefficient ◽

South Pacific ◽

Particle Beam ◽

Trophic Conditions ◽

Carbon Biomass ◽

Organic Carbon Concentration ◽

Total Particle

Abstract. Prochlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration (POC), derived from the total particle beam attenuation coefficient (cp), were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which is not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%), this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particulate attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both Tchla and cp. Finally, picophytoeukaryotes contributed with ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by direct size measurements on cells sorted by flow cytometry and optical theory. The role of picophytoeukaryotes in carbon and energy flow would therefore be very important, even under hyper-oligotrophic conditions.

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