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Using rare earth elements to constrain particulate organic carbon flux in the East China Sea

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ABSTRACT

Fluxes of particulate organic carbon (POC) in the East China Sea (ECS) have been reported to decrease from the inner continental shelf towards the outer continental shelf. Recent research has shown that POC fluxes in the ECS may be overestimated due to active sediment resuspension. To better characterize the effect of sediment resuspension on particle fluxes in the ECS, rare earth elements (REEs) and organic carbon (OC) were used in separate two-member mixing models to evaluate trap-collected POC fluxes. The ratio of resuspended particles from sediments to total trap-collected particles in the ECS ranged from 82–94% using the OC mixing model, and 30–80% using the REEs mixing model, respectively. These results suggest that REEs may be better proxies for sediment resuspension than OC in high turbidity marginal seas because REEs do not appear to undergo degradation during particle sinking as compared to organic carbon. Our results suggest that REEs can be used as tracers to provide quantitative estimates of POC fluxes in marginal seas.

No MeSH data available.


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Relationships between C-Cs and 1/TSM in the ECS.The regression lines are forced through the origin in order to use a POC value in sediments.
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f3: Relationships between C-Cs and 1/TSM in the ECS.The regression lines are forced through the origin in order to use a POC value in sediments.

Mentions: where C is the observed POC content (%) in the suspended particles, So is the total weight of surface phytoplankton (mg L−1), S is the total weight of observed suspended particles (mg L−1) in the surface water, Co is the POC content of surface phytoplankton (unknown), and Cs is the POC content we measured in surface sediment (0–2 cm). Using the measured Cs values and assuming a reasonable surface phytoplankton weight (i.e., So = 0.5 mg L−1), Co values (Table 2) were estimated by plotting (C-Cs) Versus the reciprocal of the observed TSM (1/S) and forcing the best-fit line through the origin (Fig. 3). The predicted Co values (phytoplankton POC content) ranged from 7.0 to 28.1%, which are similar to the POC contents (8.1–16.8%) for the predominate phytoplankton species in the ECS1.


Using rare earth elements to constrain particulate organic carbon flux in the East China Sea
Relationships between C-Cs and 1/TSM in the ECS.The regression lines are forced through the origin in order to use a POC value in sediments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037389&req=5

f3: Relationships between C-Cs and 1/TSM in the ECS.The regression lines are forced through the origin in order to use a POC value in sediments.
Mentions: where C is the observed POC content (%) in the suspended particles, So is the total weight of surface phytoplankton (mg L−1), S is the total weight of observed suspended particles (mg L−1) in the surface water, Co is the POC content of surface phytoplankton (unknown), and Cs is the POC content we measured in surface sediment (0–2 cm). Using the measured Cs values and assuming a reasonable surface phytoplankton weight (i.e., So = 0.5 mg L−1), Co values (Table 2) were estimated by plotting (C-Cs) Versus the reciprocal of the observed TSM (1/S) and forcing the best-fit line through the origin (Fig. 3). The predicted Co values (phytoplankton POC content) ranged from 7.0 to 28.1%, which are similar to the POC contents (8.1–16.8%) for the predominate phytoplankton species in the ECS1.

View Article: PubMed Central - PubMed

ABSTRACT

Fluxes of particulate organic carbon (POC) in the East China Sea (ECS) have been reported to decrease from the inner continental shelf towards the outer continental shelf. Recent research has shown that POC fluxes in the ECS may be overestimated due to active sediment resuspension. To better characterize the effect of sediment resuspension on particle fluxes in the ECS, rare earth elements (REEs) and organic carbon (OC) were used in separate two-member mixing models to evaluate trap-collected POC fluxes. The ratio of resuspended particles from sediments to total trap-collected particles in the ECS ranged from 82–94% using the OC mixing model, and 30–80% using the REEs mixing model, respectively. These results suggest that REEs may be better proxies for sediment resuspension than OC in high turbidity marginal seas because REEs do not appear to undergo degradation during particle sinking as compared to organic carbon. Our results suggest that REEs can be used as tracers to provide quantitative estimates of POC fluxes in marginal seas.

No MeSH data available.


Related in: MedlinePlus