Effective Vertical Transport of Particulate Organic Carbon in the Western North Pacific Subarctic Region

Honda, Makio C.

doi:10.3389/feart.2020.00366

Cited by 16 publications

(13 citation statements)

References 77 publications

(141 reference statements)

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“…To limit complexity, the biogeochemical parameters of our model were globally uniform, POC and POP had the same flux profiles, and DOC and DOP had identical remineralization timescales. In the real ocean, most of these parameters vary spatially (for variations in flux profiles, see, e.g., Honda, 2020; Marsay et al., 2015; Weber et al., 2016), and there is evidence that PO 4 is remineralized preferentially relative to carbon (Letscher & Moore, 2015). The remineralization rate of CaCO 3 also depends on the saturation state of seawater with respect to crystalline CaCO 3 and a globally uniform PIC remineralization length scale is a simplifying approximation.…”

Section: Discussionmentioning

confidence: 99%

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂

Holzer

Kwon

Pasquier

2021

Global Biogeochemical Cycles

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We develop novel locally defined diagnostics for the efficiency of the ocean's biological pump by tracing carbon throughout its lifetime in the ocean from gas injection to outgassing and counting the number of passages through the soft‐tissue and carbonate pumps. These diagnostics reveal that the biological pump's key controls on atmospheric pCO2 are the mean number of lifetime pump passages per dissolved inorganic carbon (DIC) molecule at the surface and the mean aphotic sequestration time of regenerated DIC. We apply our diagnostics to an observationally constrained carbon‐cycle model that features spatially varying stoichiometric ratios and is embedded in a data‐assimilated global ocean circulation. We find that for the present‐day ocean an average of 44 ± 4% of DIC in a given water parcel makes at least one lifetime passage through the soft tissue pump, and about 4% makes at least one passage through the carbonate pump. The global mean number of lifetime pump passages per molecule, including the fraction with zero passages, is trueN¯soft=0.65±0.08 and trueN¯carb∼0.04 for the soft‐tissue and carbonate pumps. Using idealized perturbations to sweep out a sequence of states ranging from zero biological activity (normalpnormalCnormalO2atm=493±1 ppmv) to complete surface nutrient depletion (normalpnormalCnormalO2atm=207±1 ppmv), we find that fractional changes in normalpnormalCnormalO2atm are dominated by fractional changes in the number of soft‐tissue pump passages. At complete surface nutrient depletion, the mean fraction of DIC that has at least one lifetime passage through the soft‐tissue pump increases to 69 ± 5% with trueN¯soft=1.6±0.3.

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Section: Discussionmentioning

confidence: 99%

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂

Holzer

Kwon

Pasquier

2021

Global Biogeochemical Cycles

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“…In addition to the general spring blooms associated with seasonal stratification after winter mixing, episodic blooms contribute to POC formation from winter to late spring. Time-series observations show that settling particles collected at S1 are largest in winter and spring and undergo substantial seasonal and interannual variability (Honda, 2020). Our study suggests that changes in the magnitude of the bloom and the timing of the onset and demise are associated with the behavior of the wintertime MLD and contribute to the seasonal and interannual variability of carbon export.…”

Section: Model Analysis Of Bloom Formation With the Behavior Of Wintertime Mlds And Its Implications For Biogeochemistrymentioning

confidence: 65%

“…In this region, the process of bloom formation is thought to be more complex, as it is observed in winter and late spring. The settling of particles at S1 increases significantly from winter to spring (Honda, 2020). It is clear that the formation of blooms during winter and spring has an impact on carbon fluxes.…”

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confidence: 97%

The Formation of Subtropical Phytoplankton Blooms Is Dictated by Water Column Stability During Winter and Spring in the Oligotrophic Northwestern North Pacific

et al. 2021

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The North Pacific subtropical gyre (NPSG) has often been referred to as an "ocean desert" because of its low chlorophyll a (chl-a) concentration, which is caused by its stable water column structure and nutrient limitation in the euphotic zone. Most biogeochemical studies of this region have been conducted in the central North Pacific as part of the U.S. Joint Global Ocean Flux Study that began in the late 1980s (D. M. Karl & Lukas, 1996). In the central NPSG, surface chl-a concentrations are low throughout the year, averaging less than 0.1 mg m −3 but vary seasonally with a peak in winter and ebb in summer (Chavez et al., 2011). Interestingly, however, phytoplankton blooms (hereinafter referred to as "blooms") do occur in summer in this region. The processes underlying these blooms include nitrogen fixation, eddy interactions, internal waves, and mixing at the subtropical front (Chow et al., 2017(Chow et al., , 2019. Outside of the central North Pacific, the K2S1 project was established in the northwestern North Pacific to compare the biogeochemistry of subarctic and subtropical waters during 2010 and 2011 (Honda et al., 2017). This project involved the creation of a subtropical station in the south of the Kuroshio Extension in the northwestern NPSG (S1: 145°E, 30°N).

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“…In this study, we focus on the role of seasonal atmospheric deposition in affecting POC export. The seasonal variability of POC fluxes observed by sediment traps at 200, 500, and 4,810 m all synchronized with that of surface primary productivity (Honda, 2020;Uchimiya et al, 2018). Since the seasonal variability of lateral transport flux is not clear in this region, we assume that the observed seasonal variability at 4,810 m was largely attributed to the local process.…”

Section: Resultsmentioning

confidence: 84%

Impact of Atmospheric Deposition on Carbon Export to the Deep Ocean in the Subtropical Northwest Pacific

Xiu

Chai

2021

Geophysical Research Letters

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Atmospheric deposition is one of the major external nutrients sources for the open ocean (Duce et al., 1991; Jickells et al., 2005). Inorganic nutrients (nitrogen (N), phosphorus (P), and iron (Fe)) inputs due to atmospheric deposition can increase phytoplankton growth by alleviating macronutrient and/or micronutrient limitation (Duce et al., 2008; Young et al., 1991). Lithogenic particles associated with atmospheric deposition (e.g., dust), on the other hand, can remove soluble iron of water column via scavenging (Tagliabue et al., 2017). They are also involved in particle aggregation, and act as ballast for organic material export (Armstrong et al., 2002). Studies in the high-nutrient-low-chlorophyll region reported significant enhancements of phytoplankton biomass and particulate organic carbon (POC) due to the iron addition by dust (Bishop et al., 2002; Boyd et al., 1998). In oligotrophic waters, atmospheric deposition has been shown to enhance nitrogen fixation by supplying both iron and phosphorus in the eastern tropical North Atlantic (Mills et al., 2004), and also has the potential to change the phytoplankton community structure, depending on the local nutrient-limiting condition (

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Effective Vertical Transport of Particulate Organic Carbon in the Western North Pacific Subarctic Region

Cited by 16 publications

References 77 publications

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂

The Formation of Subtropical Phytoplankton Blooms Is Dictated by Water Column Stability During Winter and Spring in the Oligotrophic Northwestern North Pacific

Impact of Atmospheric Deposition on Carbon Export to the Deep Ocean in the Subtropical Northwest Pacific

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Effective Vertical Transport of Particulate Organic Carbon in the Western North Pacific Subarctic Region

Cited by 16 publications

References 77 publications

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO2

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO2

The Formation of Subtropical Phytoplankton Blooms Is Dictated by Water Column Stability During Winter and Spring in the Oligotrophic Northwestern North Pacific

Impact of Atmospheric Deposition on Carbon Export to the Deep Ocean in the Subtropical Northwest Pacific

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A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂

A New Metric of the Biological Carbon Pump: Number of Pump Passages and Its Control on Atmospheric pCO₂