Quantifying the time lag between organic matter production and export in the surface ocean: Implications for estimates of export efficiency

Stange, Paul; Bach, Lennart T.; Moigne, Frédéric A.C. Le; Taucher, Jan; Boxhammer, Tim; Riebesell, Ulf

doi:10.1002/2016gl070875

Cited by 39 publications

(39 citation statements)

References 51 publications

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“…This is in agreement with results from a mesocosm study, which noted that decoupling at the start of the spring bloom resulted in a low export efficiency (Stange et al, 2017). The authors argue that as zooplankton populations are still low early in the year, production is retained in the upper ocean due to a lack of processing by zooplankton.…”

Section: Discussionsupporting

confidence: 89%

Drivers of Carbon Export Efficiency in the Global Ocean

Henson

Moigne

Giering

2019

Global Biogeochemical Cycles

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114

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The export of organic carbon from the surface ocean forms the basis of the biological carbon pump, an important planetary carbon flux. Typically, only a small fraction of primary productivity (PP) is exported (quantified as the export efficiency: export/PP). Here we assemble a global data synthesis to reveal that very high export efficiency occasionally occurs. These events drive an apparent inverse relationship between PP and export efficiency, which is opposite to that typically used in empirical or mechanistic models. At the global scale, we find that low PP, high export efficiency regimes tend to occur when macrozooplankton and bacterial abundance are low. This implies that a decoupling between PP and upper ocean remineralization processes can result in a large fraction of PP being exported, likely as intact cells or phytoplankton‐based aggregates. As the proportion of PP being exported declines, macrozooplankton and bacterial abundances rise. High export efficiency, high PP regimes also occur infrequently, possibly associated with nonbiologically mediated export of particles. A similar analysis at a biome scale reveals that the factors affecting export efficiency may be different at regional and global scales. Our results imply that the whole ecosystem structure, rather than just the phytoplankton community, is important in setting export efficiency. Further, the existence of low PP, high export efficiency regimes imply that biogeochemical models that parameterize export efficiency as increasing with PP may underestimate export flux during decoupled periods, such as at the start of the spring bloom.

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Section: Discussionsupporting

confidence: 89%

Drivers of Carbon Export Efficiency in the Global Ocean

Henson

Moigne

Giering

2019

Global Biogeochemical Cycles

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110

114

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“…These are primarily related to the lateral advection of POC during sinking and the time lag between primary production and export. Both must be taken into account to correctly link particles collected at depth with the plankton communities that actually produced them (Henson et al, ; Prahl et al, ; Stange et al, ). In situ mesocosms have been suggested as an important tool to overcome the spatial and temporal challenges associated with oceanic sampling (Bach et al, ; Legendre et al, ; Sanders et al, ).…”

Section: Introductionmentioning

confidence: 99%

The Influence of Plankton Community Structure on Sinking Velocity and Remineralization Rate of Marine Aggregates

Bach

Stange

Taucher

et al. 2019

Global Biogeochemical Cycles

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Gravitational sinking of photosynthetically fixed particulate organic carbon (POC) constitutes a key component of the biological carbon pump. The fraction of POC leaving the surface ocean depends on POC sinking velocity (SV) and remineralization rate (Cremin), both of which depend on plankton community structure. However, the key drivers in plankton communities controlling SV and Cremin are poorly constrained. In fall 2014, we conducted a 6‐week mesocosm experiment in the subtropical NE Atlantic Ocean to study the influence of plankton community structure on SV and Cremin. Oligotrophic conditions prevailed for the first 3 weeks, until nutrient‐rich deep water injected into all mesocosms stimulated diatom blooms. SV declined steadily over the course of the experiment due to decreasing CaCO3 ballast and—according to an optical proxy proposed herein—due to increasing aggregate porosity mostly during an aggregation event after the diatom bloom. Furthermore, SV was positively correlated with the contribution of picophytoplankton to the total phytoplankton biomass. Cremin was highest during a Synechococcus bloom under oligotrophic conditions and in some mesocosms during the diatom bloom after the deep water addition, while it was particularly low during harmful algal blooms. The temporal changes were considerably larger in Cremin (max. fifteenfold) than in SV (max. threefold). Accordingly, estimated POC transfer efficiency to 1,000 m was mainly dependent on how the plankton community structure affected Cremin. Our approach revealed key players and interactions in the plankton food web influencing POC export efficiency thereby improving our mechanistic understanding of the biological carbon pump.

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“…The SDI was calculated on a daily basis and does therefore not account for the time lag between POM production and sinking of POM to the sediment traps (Stange et al, 2017). The reason for this was that the time lag could only be accurately determined during the bloom, when clear peaks in biomass production and POM flux to the sediment traps were observed.…”

Section: Estimating Degradation Of Sinking Particles Based On Stoichomentioning

confidence: 99%

Ocean Acidification-Induced Restructuring of the Plankton Food Web Can Influence the Degradation of Sinking Particles

et al. 2018

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Ocean acidification (OA) is expected to alter plankton community structure in the future ocean. This, in turn, could change the composition of sinking organic matter and the efficiency of the biological carbon pump. So far, most OA experiments involving entire plankton communities have been conducted in meso-to eutrophic environments. However, recent studies suggest that OA effects may be more pronounced during prolonged periods of nutrient limitation. In this study, we investigated how OA-induced changes in low-nutrient adapted plankton communities of the subtropical North Atlantic Ocean may affect particulate organic matter (POM) standing stocks, POM fluxes, and POM stoichiometry. More specifically, we compared the elemental composition of POM suspended in the water column to the corresponding sinking material collected in sediment traps. Three weeks into the experiment, we simulated a natural upwelling event by adding nutrient-rich deep-water to all mesocosms, which induced a diatom-dominated phytoplankton bloom. Our results show that POM was more efficiently retained in the water column in the highest CO 2 treatment levels (>800 µatm pCO 2 ) subsequent to this bloom. We further observed significantly lower C:N and C:P ratios in post-bloom sedimented POM in the highest CO 2 treatments, suggesting that degradation processes were less pronounced. This trend is most likely explained by differences in micro-and mesozooplankton abundance during the bloom and postbloom phase. Overall, this study shows that OA can indirectly alter POM fluxes and stoichiometry in subtropical environments through changes in plankton community structure.

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Quantifying the time lag between organic matter production and export in the surface ocean: Implications for estimates of export efficiency

Cited by 39 publications

References 51 publications

Drivers of Carbon Export Efficiency in the Global Ocean

Drivers of Carbon Export Efficiency in the Global Ocean

The Influence of Plankton Community Structure on Sinking Velocity and Remineralization Rate of Marine Aggregates

Ocean Acidification-Induced Restructuring of the Plankton Food Web Can Influence the Degradation of Sinking Particles

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