Tidal variation shaped microplastic enrichment patterns in mangrove blue carbon ecosystem of northern Beibu Gulf, China

Abstract

Mangroves are considered to be a sink for microplastics (MPs) due to their unique characteristics. Previous studies mainly focused on the spatial distribution of MPs, but few researchers have addressed the influence of tidal variation on this distribution, especially since the MP total number in mangroves was unknown. In this study, surface sediment samples were collected in mangroves from the Beibu Gulf, South China Sea, and the abundance, composition, and number of MPs were investigated. The results showed that MPs were widely present in all mangrove sediment samples, with abundances ranging from 26.67 ± 9.43 to 239.94 ± 37.80 items/kg. The distribution of MPs was heterogeneous among different sampling sites, with the highest levels in the Shankou (SK) area. The MP abundance in the same mangrove forest gradually increased from the low tidal zone to the high tidal zone, with the enrichment factor ranging from 1.50 to 4.00. The MP abundance was significantly correlated with particulate organic carbon (POC) (n = 12, R = 0.664, p < 0.05). Results showed that mangroves had an interception effect on MPs and factors affecting MP distribution in mangrove sediments included not only tides but also human activities, such as aquaculture, agriculture, and residential life. Finally, this paper estimated the MP total number in mangroves at different sampling areas and tidal zones, and the middle tidal zone was considered to be more accurate for MP pollution assessment in mangroves.

Human activities altered the enrichment patterns of microplastics in mangrove blue carbon ecosystem in the semi-enclosed Zhanjiang Bay, China

“…However, the results showed that the size and color diversity were greater than the shape in mangroves and nonmangroves. These results were consistent with the previous study in the seasonal diversity variation of MPs from land-based sources and the Beibu Gulf mangrove sediments (Wang et al, 2022;Zhang et al, 2022). In addition, in this study, the highest S3 MPs abundance was found in the mangrove sampling area with an EI value of 11.63.…”

“…The MPs abundance in ZJB is intermediate compared to foreign contamination, including Muara Angke Wildlife Reserve of Indonesia (28.09 ± 10.28 items/kg), Northern Persian Gulf of (19.5 to 34.5 items/kg), Kuala Muda of Malaysia (430 ± 7.234 items/kg), Penaga of Malaysia (940 ± 15.773 items/kg), Seberang Perai of Malaysia (4000 ± 29.174 items/kg) (Naji et al, 2019;Cordova et al, 2021;Tan and Mohd Zanuri, 2023). Compared with mangrove sediments from other regions of China, it was much higher than that of the North Yellow Sea (37.1 ± 42.7 items/kg), Beibu Bay (26.67 ± 9.43 to 239.94 ± 37.80 items/kg), inside the mangrove of Qinzhou Bay (42.9 ± 26.8 items/kg) (Zhu et al, 2018;Li et al, 2018a;Zhang et al, 2022), lower than outside the mangrove of Qinzhou Bay (2174.5 ± 2206.8 items/kg), Pearl River Estuary, South China (851 ± 177 items/kg), the fringe in Futian mangrove in Shenzhen Bay (2835 ± 713 items/kg) (Li et al, 2018a;Zuo et al, 2020;Duan et al, 2021). Each study may have used a different MPs extraction method and different filters will result in subtle differences.…”

“…The study analysed the sample sizes of MPs, which were divided into six categories: 0-100 μm, 100-330 μm, 330-500 μm, 500-1000 μm, 1000-2000 μm, and 2000-5000 μm (Wang et al, 2022;Zhang et al, 2022). The size of the MPs did not differ significantly between station (P > 0.05).…”

“…There was no significant difference in POC between mangrove and nonmangrove areas (P > 0.05). Zhang et al 10.3389/fmars.2024.1362170 abundance, such as agricultural activities, aquaculture (Hinojosa and Thiel, 2009), wastewater discharge (Gies et al, 2018), tourism activities, residential life, tidal action (Zhang et al, 2022), and seasonal variations (Wang et al, 2022). A comparison of MPs abundance in dry mangrove sediments from different regions is shown in Table 2.…”

Isolation, Structure Elucidation, and First Total Synthesis of Quinomycins K and L, Two New Octadepsipeptides from the Maowei Sea Mangrove-Derived Streptomyces sp. B475

“…The Beibu Gulf is located in the northwestern continental shelf area of the South China Sea, from the Leizhou Peninsula, Qiongzhou Strait, and Hainan Island to Vietnam and northward to Guangxi. The mangrove species in this region are very rich, and mangrove in the region is ranked as the second-largest area and accounts for more than 37% of the total mangrove area in China [ 5 ]. Recently, our group has discovered many new actinomycetia taxa along with novel bioactive compounds from mangroves in the Beibu Gulf, such as the Maowei Sea [ 6 , 7 ], Beilun Estuary [ 8 , 9 , 10 ], and Leizhou Peninsula [ 11 ].…”