Transparent exopolymer particle dynamics along a shelf-to-sea gradient and impacts on the regional carbon cycle

Ge, Zaiming; Li, Qian P.; Yang, Weifeng; Liu, Xin; Wu, Zhiwei

doi:10.1016/j.scitotenv.2021.152117

Cited by 9 publications

(3 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, the northeastern SCS was selected to investigate the influence of horizontal advection on the estimation of 234 Th flux (Figure 1). Over the past decade, increasing studies report the widely observed cross-shelf dispersion of particulate matter (Shih et al, 2019;Shen et al, 2020;Yang et al, 2021b;Ge et al, 2022) driven by the dynamic physical processes (Li et al, 2018;Jia et al, 2019). Thus, the northeastern SCS could be an ideal site for attesting to the influence of physical processes on the application of the 234 Th/ 238 U method.…”

Section: Introductionmentioning

confidence: 99%

Lagrangian Observation of 234Th and Its Application in Constraining the Sinking of Particulate Organic Carbon on the Slope of the Northeastern South China Sea

et al. 2022

Self Cite

View full text Add to dashboard Cite

The 234Th–238U disequilibrium has been widely used to quantify the sinking flux of particulate organic carbon (POC) out of the upper ocean. However, the influence of the advection on the quantification is poorly understood due to the lack of in situ measured physical parameters. Here, a Lagrangian observation was deployed for 39 h to track the variability of 234Th along with the current on the slope of the northeastern South China Sea (SCS). Contrasting to the general ocean interior, 234Th showed deficits relative to 238U in the mesopelagic waters, indicating an enhanced removal of 234Th. Concurrently, elevated total particulate matter (TPM) and POC contents were observed in the mesopelagic waters, supporting the driving force of the cross-shelf dispersion of re-suspended shelf/slope sediments for the 234Th removal. The widely used 234Th-model (ignoring physical processes) produced a much lower sinking flux of POC than the sediment trap-derived POC flux during the same observation, indicating an unneglectable influence of advection and diffusion. By considering the main horizontal advection and vertical diffusion, the 234Th–238U method gave rise to comparable results to sediment trap. 234Th-derived POC fluxes showed an increased pattern from 300 to 1,000 m, consistent with the more abundant POC where. These results indicated that advection represents an unneglectable process during the quantification of the sinking flux of 234Th over the slope of the SCS.

show abstract

Section: Introductionmentioning

confidence: 99%

Lagrangian Observation of 234Th and Its Application in Constraining the Sinking of Particulate Organic Carbon on the Slope of the Northeastern South China Sea

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…Planktonic organisms can accelerate the aggregation of an individual particle by acting as nucleation and thus increase their sinking rate (Riley et al, 2012). In addition, our recent study found that the sticky transparent exopolymer particles (TEP) largely favor the formation of aggregates in the northern SCS (Ge et al, 2022). It is likely that the two factors jointly resulted in the maxima velocity beneath the euphotic zones at E1 and F2.…”

Section: Po-derived Sinking Speed Of Particlesmentioning

confidence: 99%

Slow-sinking particulate organic carbon and its attenuation in the mesopelagic water of the South China Sea

2022

Self Cite

View full text Add to dashboard Cite

Coastal acidification has been widely investigated in terms of its rationale and ecological effects in the last decade. However, the driving mechanism for acidification in open seawater, especially in mesopelagic water, is still poorly understood. Here, the sinking velocity and flux attenuation of particulate organic carbon (POC) were examined based upon the radioactive 210Po-210Pb tracer to reveal the remineralization of POC in the mesopelagic zone in the northeastern South China Sea (SCS). Overall, the profiles of 210Po followed those of 210Pb, lending support to the particle sinking controlled top-down deficits of 210Po. Using an inverse model, the sinking velocity of particles, for the first time in the SCS, was estimated to vary from 3 to 34 m d-1 with the mean value of 15 ± 9 m d-1, indicating that the slow sinking particles largely contribute to the POC flux in the SCS. Beneath the euphotic zone, a consistent descending of the sinking speed implied continuous remineralization of sinking POC in the twilight zone. A preliminary estimate revealed that 1.9-5.4 mmol-C m-2 d-1 remineralized back to carbon dioxide within 100-500 m, representing about 70% of the exported autochthonous POC from the euphotic zone. In 100-1000 m, 2.4-6.6 mmol-C m-2 d-1 (i.e., 84%) remineralized. Thus, the upper twilight zone (i.e., 100-500 m) is the dominant layer of POC remineralization, and POC-induced acidification could be unneglectable there. These results provided insights into the POC-induced acidification mechanism in the mesopelagic water, especially in the upper mesopelagic layer.

show abstract

“…Thus, TEPs play an important role in the size conversion from the dissolved organic carbon (DOC) to the particulate organic carbon (POC) [ 9 , 10 , 11 ]. Therefore, a better understanding of the carbon contributed by TEP in DOC and POC is crucial in order to investigate the fates of organic matter in the ocean [ 7 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Temperature on Transparent Exopolymer Particle Production and Organic Carbon Allocation of Four Marine Phytoplankton Species

Guo

Chen

Yuan

et al. 2022

Biology

View full text Add to dashboard Cite

Transparent exopolymer particles (TEP) are sticky polymeric substances that are commonly found in the periphery of microbial cells or colonies. They can naturally flocculate smaller suspended particles into larger aggregates and thus play a crucial role in the biological pump and the global carbon cycle. Phytoplankton are the major contributors to marine TEP production, whereas the way TEP production interacts with abiotic factors at the species level is generally unknown but critical for estimating carbon fluxes. In this study, the effects of temperature on TEP production and carbon allocation were studied in two representative diatom species (Nitzschia closterium and Chaetoceros affinis) and two model dinoflagellate species (Prorocentrum micans and Scrippisella trichoidea). The results showed that temperature had a significant impact on TEP production in all species. First, increased temperature promoted the TEP production of all four species. Second, elevated temperature affected the carbon pool allocation, with enhanced dissolved organic carbon (DOC) exudation in the form of TEP in all species. The TEP-C/DOC percentages of N. closterium and P. micans were 93.42 ± 5.88% and 82.03 ± 21.36% at the highest temperature (24 °C), respectively, which was approximately two to five times higher than those percentages at 16 °C. In contrast, TEP’s contribution to the POC pool is lower than that to the DOC pool, ranging from 6.74 ± 0.79% to 28.31 ± 1.79% for all species. Moreover, phytoplankton TEP production may be related to cellular size and physiology. The TEP content produced by the smallest N. closterium (218.96 ± 15.04 fg Xeq./μm3) was ~5 times higher compared to P. micans, S. trichoidea, or C. affinis. In conclusion, TEP production is temperature sensitive and species specific, which should be taken into consideration the regarding TEP-mediated oceanic carbon cycle, particularly in the context of global warming.

show abstract

Transparent exopolymer particle dynamics along a shelf-to-sea gradient and impacts on the regional carbon cycle

Cited by 9 publications

References 48 publications

Lagrangian Observation of 234Th and Its Application in Constraining the Sinking of Particulate Organic Carbon on the Slope of the Northeastern South China Sea

Lagrangian Observation of 234Th and Its Application in Constraining the Sinking of Particulate Organic Carbon on the Slope of the Northeastern South China Sea

Slow-sinking particulate organic carbon and its attenuation in the mesopelagic water of the South China Sea

Effects of Temperature on Transparent Exopolymer Particle Production and Organic Carbon Allocation of Four Marine Phytoplankton Species

Contact Info

Product

Resources

About