Dual mobilization of buried microplastics and organic carbon driven by seagrass degradation: a case study from Swan Lake, China

IF 2.8 2区生物学 Q1 MARINE & FRESHWATER BIOLOGY

Frontiers in Marine Science Pub Date : 2025-05-29 DOI:10.3389/fmars.2025.1593776

Yuzhou Huang, Shuo Yu, Zhenming Zheng, Xi Xiao, Zuhao Zhu, Liangchao Deng, Huihua Wei, Jiani Liang, Shuilan Chen, Marianne Holmer

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引用次数: 0

Abstract

Seagrass beds are significant sinks for microplastics. However, the degradation of seagrass beds poses significant challenges, and evidence regarding its impacts on microplastic sinks remains scarce. In this study, sediment cores were collected to investigate microplastic stock and composition, microplastic carbon, and organic carbon stock in Zostera japonica seagrass bed and adjacent degraded area in a lagoon Swan Lake, China. The microplastic stock in seagrass bed (84.5 ± 18.5 million particles ha-1) was found significantly higher than degraded area (51.8 ± 0.6 million particles ha-1), resulting in release of 38.7% of buried microplastics reactivated in water column. Similarly, 30.0% of the microplastic carbon stock and 66.1% of the total organic carbon stock were eroded due to seagrass degradation. The carbon stocks derived from microplastics were estimated at 0.19 ± 0.10 kg C ha-1 in the seagrass bed and 0.13 ± 0.11 kg C ha-1 in the degraded area, contributing minimally to the total organic carbon stock (0.0023% and 0.0026%, respectively). Notably, seagrass degradation within a single year may trigger rapid erosion of organic carbon and microplastics buried for over 20 years in Swan Lake. A linear relationship was observed between sediment microplastic carbon and total organic carbon contents (Organic carbon = 1990 + 35100 × Microplastic carbon, R² = 0.26, p < 0.001). Microplastics in the sediments were predominantly fiber (48.1%), black (40.7%), 250–500 µm (47.0%) microplastics in degraded area, while plate (26.7%), blue and transparent, each contributing 26.7% and 125–250 µm (38.2%) in seagrass bed. Seagrass bed degradation may not only reduce the stock of microplastics in the sediments but also alter their composition. This study initially quantified the contribution of microplastics to organic carbon stocks in seagrass bed sediments and underscored the urgent need for seagrass conservation to mitigate climate change and prevent the remobilization of historically buried microplastics.

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海草降解驱动的埋藏微塑料和有机碳的双重动员：中国天鹅湖的案例研究

海草床是微塑料的重要水槽。然而，海草床的退化带来了重大挑战，关于其对微塑料水槽影响的证据仍然很少。本研究通过采集沉积物岩心，研究了泻湖天鹅湖海域日本斑藻（Zostera japonica）海草床及其邻近退化区微塑料储量及其组成、微塑料碳和有机碳储量。海草床的微塑料存量（8450±1850万粒ha-1）显著高于降解区（5180±60万粒ha-1），导致38.7%的埋藏微塑料在水柱中被重新激活。同样，30.0%的微塑料碳储量和66.1%的总有机碳储量由于海草的降解而被侵蚀。微塑料产生的碳储量在海草床为0.19±0.10 kg C ha-1，在退化区为0.13±0.11 kg C ha-1，对总有机碳储量的贡献最小（分别为0.0023%和0.0026%）。值得注意的是，一年内的海草退化可能会引发埋藏在天鹅湖20多年的有机碳和微塑料的快速侵蚀。沉积物微塑性碳与总有机碳含量呈线性关系(有机碳= 1990 + 35100 ×微塑性碳，R²= 0.26,p <；0.001)。沉积物中的微塑料以纤维（48.1%）、黑色（40.7%）和250 ~ 500µm（47.0%）微塑料为主，而板状（26.7%）、蓝色和透明微塑料在海草床中分别占26.7%和125 ~ 250µm（38.2%）。海草床的降解不仅会减少沉积物中微塑料的存量，还会改变它们的组成。本研究初步量化了微塑料对海草床沉积物中有机碳储量的贡献，并强调了保护海草以缓解气候变化和防止历史埋藏的微塑料重新动员的迫切需要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Frontiers in Marine Science Agricultural and Biological Sciences-Aquatic Science

CiteScore

5.10

自引率

16.20%

发文量

2443

审稿时长

14 weeks

期刊介绍： Frontiers in Marine Science publishes rigorously peer-reviewed research that advances our understanding of all aspects of the environment, biology, ecosystem functioning and human interactions with the oceans. Field Chief Editor Carlos M. Duarte at King Abdullah University of Science and Technology Thuwal is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, policy makers and the public worldwide. With the human population predicted to reach 9 billion people by 2050, it is clear that traditional land resources will not suffice to meet the demand for food or energy, required to support high-quality livelihoods. As a result, the oceans are emerging as a source of untapped assets, with new innovative industries, such as aquaculture, marine biotechnology, marine energy and deep-sea mining growing rapidly under a new era characterized by rapid growth of a blue, ocean-based economy. The sustainability of the blue economy is closely dependent on our knowledge about how to mitigate the impacts of the multiple pressures on the ocean ecosystem associated with the increased scale and diversification of industry operations in the ocean and global human pressures on the environment. Therefore, Frontiers in Marine Science particularly welcomes the communication of research outcomes addressing ocean-based solutions for the emerging challenges, including improved forecasting and observational capacities, understanding biodiversity and ecosystem problems, locally and globally, effective management strategies to maintain ocean health, and an improved capacity to sustainably derive resources from the oceans.