Estimation of the Particulate Organic Carbon to Chlorophyll-a Ratio Using MODIS-Aqua in the East/Japan Sea, South Korea

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.

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Ocean color algorithms to estimate the concentration of particulate organic carbon in surface waters of the global ocean in support of a long-term data record from multiple satellite missions

Remote Sensing of Environment ◽

10.1016/j.rse.2021.112776 ◽

2022 ◽

Vol 269 ◽

pp. 112776

Author(s):

Dariusz Stramski ◽

Ishan Joshi ◽

Rick A. Reynolds

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Surface Waters ◽

Ocean Color ◽

Global Ocean ◽

Data Record ◽

Satellite Missions ◽

Term Data

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Estimates of particulate organic carbon over the euphotic depth from in situ measurements. Application to satellite data over the global ocean

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/j.dsr.2009.12.007 ◽

2010 ◽

Vol 57 (3) ◽

pp. 351-367 ◽

Cited By ~ 29

Author(s):

L. Duforêt-Gaurier ◽

H. Loisel ◽

D. Dessailly ◽

K. Nordkvist ◽

S. Alvain

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Satellite Data ◽

In Situ Measurements ◽

Global Ocean ◽

Euphotic Depth

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Comparison of in situ and satellite ocean color determinations of particulate organic carbon concentration in the global ocean

Oceanologia ◽

10.1016/j.oceano.2014.09.002 ◽

2015 ◽

Vol 57 (1) ◽

pp. 25-31 ◽

Cited By ~ 16

Author(s):

Marek Świrgoń ◽

Malgorzata Stramska

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Carbon Concentration ◽

Ocean Color ◽

Global Ocean ◽

Particulate Organic Carbon Concentration ◽

Organic Carbon Concentration ◽

Satellite Ocean Color

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The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

10.26434/chemrxiv.7803698 ◽

2019 ◽

Author(s):

Michael Stukel ◽

Thomas Kelly

Keyword(s):

Organic Carbon ◽

Water Column ◽

Particulate Organic Carbon ◽

Transport Model ◽

California Current ◽

In Situ Measurements ◽

Power Law Distribution ◽

Sinking Particles ◽

Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

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