Global patterns in efficiency of particulate organic carbon export and transfer to the deep ocean

Abstract. Particulate organic carbon (POC) flux estimated from POC concentration observations from sediment traps and 234Th are compiled across the global ocean. The compilation includes six time series locations: CARIACO, K2, OSP, BATS, OFP and HOT. Efficiency of the biological pump of carbon to the deep ocean depends largely on biologically mediated export of carbon from the surface ocean and its remineralization with depth, thus biologically related parameters able to be estimated from satellite observations were merged at the POC observation sites. Satellite parameters include: net primary production, percent microplankton, sea surface temperature, photosynthetically active radiation, diffuse attenuation coefficient at 490 nm, euphotic zone depth, as well as, climatological mixed layer depth. 85 % of the observations across the globe are concentrated in the Northern Hemisphere with 44 % of the data record overlapping the satellite record. Time series sites accounted for 36 % of the data. 71 % of the data is measured at ≥ 500 m with the most common deployment depths between 1000 and 1500 m. This dataset is valuable for investigations of CO2 drawdown, carbon export, remineralization, and sequestration. The compiled data can be freely accessed at doi:10.1594/PANGAEA.855600.

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Export fluxes in a naturally iron-fertilized area of the Southern Ocean – Part 1: Seasonal dynamics of particulate organic carbon export from a moored sediment trap

Biogeosciences ◽

10.5194/bg-12-3153-2015 ◽

2015 ◽

Vol 12 (11) ◽

pp. 3153-3170 ◽

Cited By ~ 18

Author(s):

M. Rembauville ◽

I. Salter ◽

N. Leblond ◽

A. Gueneugues ◽

S. Blain

Keyword(s):

Organic Carbon ◽

Southern Ocean ◽

Particulate Organic Carbon ◽

Sediment Trap ◽

Time Lag ◽

Deep Ocean ◽

Companion Paper ◽

Grazing Pressure ◽

Carbon Export ◽

Poc Flux

Abstract. A sediment trap moored in the naturally iron-fertilized Kerguelen Plateau in the Southern Ocean provided an annual record of particulate organic carbon and nitrogen fluxes at 289 m. At the trap deployment depth, current speeds were typically low (~ 10 cm s−1) and primarily tidal-driven (M2 tidal component). Although advection was weak, the sediment trap may have been subject to hydrodynamical and biological (swimmer feeding on trap funnel) biases. Particulate organic carbon (POC) flux was generally low (< 0.5 mmol m−2 d−1), although two episodic export events (< 14 days) of 1.5 mmol m−2 d−1 were recorded. These increases in flux occurred with a 1-month time lag from peaks in surface chlorophyll and together accounted for approximately 40% of the annual flux budget. The annual POC flux of 98.2 ± 4.4 mmol m−2 yr−1 was low considering the shallow deployment depth but comparable to independent estimates made at similar depths (~ 300 m) over the plateau, and to deep-ocean (> 2 km) fluxes measured from similarly productive iron-fertilized blooms. Although undertrapping cannot be excluded in shallow moored sediment trap deployment, we hypothesize that grazing pressure, including mesozooplankton and mesopelagic fishes, may be responsible for the low POC flux beneath the base of the winter mixed layer. The importance of plankton community structure in controlling the temporal variability of export fluxes is addressed in a companion paper.

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Using new observations and Machine Learning to improve organic sinking processes in the PlankTOM global ocean biogeochemical model

10.5194/egusphere-egu21-11356 ◽

2021 ◽

Author(s):

Anna Denvil-Sommer ◽

Corinne Le Quéré ◽

Erik Buitenhuis ◽

Lionel Guidi ◽

Jean-Olivier Irisson

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Deep Ocean ◽

Ecosystem Dynamics ◽

Global Ocean ◽

Biogeochemical Model ◽

Carbon Export ◽

Mixing Depth ◽

Chl A ◽

Biogeochemical Models

A lot of effort has been put in the representation of surface ecosystem processes in global carbon cycle models, in particular through the grouping of organisms into Plankton Functional Types (PFTs) which have specific influences on the carbon cycle. In contrast, the transfer of ecosystem dynamics into carbon export to the deep ocean has received much less attention, so that changes in the representation of the PFTs do not necessarily translate into changes in sinking of particulate matter. Models constrain the air-sea CO2 flux by drawing down carbon into the ocean interior. This export flux is five times as large as the CO2 emitted to the atmosphere by human activities. When carbon is transported from the surface to intermediate and deep ocean, more CO2 can be absorbed at the surface. Therefore, even small variability in sinking organic carbon fluxes can have a large impact on air-sea CO2 fluxes, and on the amount of CO2 emissions that remain in the atmosphere.In this work we focus on the representation of organic matter sinking in global biogeochemical models, using the PlankTOM model in its latest version representing 12 PFTs. We develop and test a methodology that will enable the systematic use of new observations to constrain sinking processes in the model. The approach is based on a Neural Network (NN) and is applied to the PlankTOM model output to test its ability to reconstruction small and large particulate organic carbon with a limited number of observations. We test the information content of geographical variables (location, depth, time of year), physical conditions (temperature, mixing depth, nutrients), and ecosystem information (CHL a, PFTs). These predictors are used in the NN to test their influence on the model-generation of organic particles and the robustness of the results. We show preliminary results using the NN approach with real plankton and particle size distribution observations from the Underwater Vision Profiler (UVP) and plankton diversity data from Tara Oceans expeditions and discuss limitations.

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234Th-derived particulate organic carbon export in the Prydz Bay, Antarctica

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-013-2842-y ◽

2013 ◽

Vol 299 (1) ◽

pp. 621-630 ◽

Cited By ~ 2

Author(s):

Hao Ma ◽

Zhi Zeng ◽

Jianhua He ◽

Zhengbing Han ◽

Wuhui Lin ◽

...

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Prydz Bay ◽

Carbon Export

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Variability in efficiency of particulate organic carbon export: A model study

Global Biogeochemical Cycles ◽

10.1002/2014gb004965 ◽

2015 ◽

Vol 29 (1) ◽

pp. 33-45 ◽

Cited By ~ 58

Author(s):

Stephanie A. Henson ◽

Andrew Yool ◽

Richard Sanders

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Carbon Export ◽

Model Study

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Particulate organic carbon export fluxes on Chukchi Shelf, western Arctic Ocean, derived from 210Po/210Pb disequilibrium

Chinese Journal of Oceanology and Limnology ◽

10.1007/s00343-015-3357-x ◽

2015 ◽

Vol 33 (3) ◽

pp. 741-747 ◽

Cited By ~ 3

Author(s):

Jianhua He ◽

Wen Yu ◽

Wuhui Lin ◽

Wu Men ◽

Liqi Chen

Keyword(s):

Organic Carbon ◽

Arctic Ocean ◽

Particulate Organic Carbon ◽

Carbon Export ◽

Western Arctic Ocean ◽

Western Arctic ◽

Chukchi Shelf

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234Th-derived particulate organic carbon export flux in the western Arctic Ocean

Chinese Journal of Oceanology and Limnology ◽

10.1007/s00343-010-9933-1 ◽

2010 ◽

Vol 28 (6) ◽

pp. 1146-1151 ◽

Cited By ~ 3

Author(s):

Wen Yu ◽

Liqi Chen ◽

Jianping Cheng ◽

Jianhua He ◽

Mingduan Yin ◽

...

Keyword(s):

Organic Carbon ◽

Arctic Ocean ◽

Particulate Organic Carbon ◽

Carbon Export ◽

Western Arctic Ocean ◽

Export Flux ◽

Western Arctic

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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 Discussions ◽

10.5194/bgd-10-14861-2013 ◽

2013 ◽

Vol 10 (9) ◽

pp. 14861-14885 ◽

Cited By ~ 1

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, 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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Export fluxes in a naturally fertilized area of the Southern Ocean, the Kerguelen Plateau: seasonal dynamic reveals long lags and strong attenuation of particulate organic carbon flux (Part 1)

Biogeosciences Discussions ◽

10.5194/bgd-11-17043-2014 ◽

2014 ◽

Vol 11 (12) ◽

pp. 17043-17087 ◽

Cited By ~ 2

Author(s):

M. Rembauville ◽

I. Salter ◽

N. Leblond ◽

A. Gueneugues ◽

S. Blain

Keyword(s):

Organic Carbon ◽

Southern Ocean ◽

Particulate Organic Carbon ◽

Sediment Trap ◽

Time Lag ◽

Deep Ocean ◽

Biomass Accumulation ◽

Companion Paper ◽

Kerguelen Plateau ◽

Poc Flux

Abstract. A sediment trap moored in the naturally iron-fertilized Kerguelen plateau in the Southern Ocean provided an annual record of particulate organic carbon and nitrogen fluxes at 289 m. At the trap deployment depth current speeds were low (∼10 cm s−1) and primarily tidal-driven (M2 tidal component) providing favorable hydrodynamic conditions for the collection of flux. Particulate organic carbon (POC) flux was generally low (<0.5 mmol m−2 d−1) although two episodic export events (<14 days) of 1.5 mmol m−2 d−1 were recorded. These increases in flux occurred with a 1 month time lag from peaks in surface chlorophyll and together accounted for approximately 40% of the annual flux budget. The annual POC flux of 98.2 ± 4.4 mmol m−2 yr−1 was relatively low considering the shallow deployment depth, but similar to deep-ocean (>2 km) fluxes measured from similarly productive iron-fertilized blooms. Comparison of the sediment trap data with complementary estimates of biomass accumulation and export indicate that ∼90% of the flux was lost between 200 and 300 m. We hypothesize that grazing pressure, including mesozooplankton and mesopelagic fishes, may be responsible for rapid flux attenuation and the High Biomass Low Export regime characterizing the Kerguelen bloom. The importance of plankton community structure in controlling the temporal variability of export fluxes is addressed in a companion paper.

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