Transparent Exopolymer Particle (TEPs) Dynamics and Contribution to Particulate Organic Carbon (POC) in Jaran Bay, Korea

Abstract

Transparent exopolymer particles (TEPs) are defined as acidic polysaccharide particles and they are influenced by various biotic and abiotic processes that play significant roles in marine biogeochemical cycles. However, little information on their monthly variation, relationship and contribution to particulate organic carbon (POC) is currently available particularly in coastal regions. In this study, the water samples were collected monthly to determine TEP concentrations and POC concentrations in a southern coastal region of Korea, Jaran Bay from April 2016 to March 2017. The TEP concentrations varied from 26.5 to 1695.4 μg Xeq L−1 (mean ± standard deviation (S.D.) = 215.9 ± 172.2 μg Xeq L−1) and POC concentrations ranged from 109.9 to 1201.9 μg L−1 (mean ± S.D. = 399.1 ± 186.5 μg L−1) during our observation period. Based on the 13C stable isotope tracer technique, monthly carbon uptake rates of phytoplankton ranged from 3.0 to 274.1 mg C m−2 h−1 (mean ± S.D. = 34.5 ± 45.2 mg C m−2 h−1). The cross-correlation analysis showed a lag-time of 2 months between chlorophyll a and TEP concentrations (r = 0.86, p < 0.01; Pearson’s correlation coefficient). In addition, we observed a 2 month lag-phased correlation between TEP concentrations and primary production (r = 0.73, p < 0.05; Pearson’s correlation coefficient). In Jaran Bay, the TEP contribution was as high as 78.0% of the POC when the TEP-C content was high and declined to 2.4% of the POC when it was low. These results showed that TEP-C could be a significant contributor to the POC pool in Jaran Bay.

Assessing the Temporal Variability and Drivers of Transparent Exopolymer Particle Concentrations and Production Rates in a Subtropical Estuary

“…While weekly TEP measurements in this study were in the range of those previously made in estuarine systems (Morelle et al 2017;Ortega-Retuerta et al 2018;Lee et al 2020), we did not observe distinct trends in TEP concentration over the seasonal cycle. Other studies have noted seasonal TEP dynamics, with the highest TEP concentrations in the summer Fig.…”

“…Estuaries are carbon-rich areas of the ocean (Hopkinson and Smith 2005) and are highly dynamic, with significant daily and seasonal changes in environmental and biological gradients (Cloern and Jassby 2010). TEP has been shown to be an important contributor to carbon export within estuarine systems (Annane et al 2015;Morelle et al 2017;Lee et al 2020), with high TEP concentrations commonly found in the maximum turbidity zone (MTZ), areas where suspended particulate material accumulates (Malpezzi et al 2013). In addition, significant concentrations of TEP in estuaries could be derived from high inputs of terrestrial detrital material that is often partially remineralized by heterotrophic bacteria (Heip et al 1995).…”

Organic Matter Composition of Biomineral Flocs and its Influence on Suspended Particulate Matter Dynamics along a Nearshore to Offshore Transect

“…A correlation of TEP concentrations with the rise and decline of phytoplankton blooms is reported from lab cultures (Fukao et al, 2010), estuarine and nearshore areas (Bhaskar & Bhosle, 2006;Chowdhury et al, 2016;Ramaiah et al, 2001), and from the open ocean (Mari et al, 2017). Others report temporary disconnection of TEP from Chl-a concentrations (J. H. Lee et al, 2020;Ortega-Retuerta et al, 2018). Our data do not reveal any clear relationship between Chl-a and TEP concentration (see Figures 2j and 2l).…”

Seasonal Variations in the Biochemical Compositions of Phytoplankton and Transparent Exopolymer Particles (TEPs) at Jang Bogo Station (Terra Nova Bay, Ross Sea), 2017–2018

“…To estimate TEP-C, we used the lowest conversion factor (0.51 µg Xeq. L −1 ) commonly used for the diatom-dominated phytoplankton community [51,102]. Considerably large variations in the contribution of TEP-C to the POC stocks were observed seasonally during our observation period (Figure 9), which was different from the seasonal pattern in the TEP concentrations.…”