Search

Coastal vegetated habitats such as mangroves, salt marshes, and seagrasses, referred to as blue carbon ecosystems, play an important role in climate change mitigation by an effective CO 2 capture from atmosphere and water columns and long-term organic carbon (C org ) storage in sediments. Although seagrass meadows are considered intense carbon sinks, information on regional variability in seagrass blue carbon stock and factors influencing its capacity still remain sparse. In the present study, seagrass blue carbon storage by measuring C org stocks in sediments and living seagrass biomass, and carbon accumulation rates (CARs) in seagrass meadows were estimated along the Korean coast. Factors affecting variability in C org stocks were also analyzed using partial least squares (PLS) regression and principal component analysis (PCA). Projected C org stocks in sediment, extrapolated to a depth 1 m, exhibited substantial variability among sites, ranging from 49.91 to 125.71 Mg C ha -1 . The majority of C org (96-99%) was stored in sediments, whereas the contribution of living biomass was minor. PLS regression and PCA indicated that C org stocks in seagrass meadows are strongly associated with sediment characteristics such as dry bulk density and water and mud content. Among seagrass traits, above- to below-ground biomass ratio was significantly related to the quantity of C org stocks in seagrass meadows. Because of the high spatial variability in C org stocks and CARs, local and regional differences in seagrass blue carbon storage should be considered to accurately assess the climate change mitigation potential of seagrass ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Given a large quantity of epiphytes and other material attached on eelgrass leaf blades, we explored the relationship between eelgrass sheaths and different-aged leaf blades (1st, 2nd, 3rd, and 4th leaf blade) on nutrient content and their ratios (C, N, P, C/N, C/P, and N/P) to identify whether eelgrass sheaths could be used to instead of leaf blades in terms of nutrient content. In addition, we explored the relationship between eelgrass sheath length and shoot length. Results showed that there were significant relationships between the sheath and leaf blades in terms of N and P content and their ratios. For length analysis, there was a significant relationship between sheath length and shoot length, and shoot length was approximately four to five times (mean 4.4659) longer than sheath length, such that shoot length can be estimated by sheath length. These significant relationships suggest that eelgrass sheath could be used as a suitable predictor of leaf blade in length and nutrient stoichiometry, thus eelgrass sheath could be used as an indicator for further eelgrass nutrient monitoring and research., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Although seagrasses can incorporate heavy metals from the marine environment, few studies have been conducted on heavy metal uptake and phytoremediation potential by seagrass transplants in the heavy metal contaminated sediments. Zostera marina shoots were transplanted in two polluted bay systems on Korean coasts to evaluate the heavy metal contaminations in sediments and the possibility of using Z. marina transplants as a bioindicator and phytoremediation agent. The major concentrated metals in sediments were As, Cu, Fe, and Pb in Jaran Bay, and Cd, Co, Zn, and Hg in Onsan Bay. The Co, Zn, Pb, and Hg concentrations in Z. marina tissues reflected the sediment heavy metal concentrations, and thus the tissue heavy metal concentrations may be used as bio-indicators of the metal contaminations. Since Z. marina transplants accumulated a great amount of heavy metals in their tissues, they may have the phytoremediation potential for the heavy metal contaminated sediments., (Copyright © 2019 Elsevier Ltd. All rights reserved.)