Mangrove wetlands are hotspots of the global nitrogen (N) cycle and important sinks of microplastics (MPs) due to their ecotone location between terrestrial and marine ecosystems. However, the effects of MPs on N cycle processes in mangrove ecosystems are still poorly understood. Thus, the present study assessed the impacts by adding MPs to mangrove sediments in a microcosm incubation experiment. The results showed that MPs increased dissolved organic carbon and nitrate but reduced ammonium contents in the sediments. MPs increased C:N stoichiometric and N:C-acquiring enzymatic ratios, indicating an intensified N limitation in mangrove sediments following exposure of MPs. MPs decreased microbial community diversity and shifted sediment microbial communities from r- to K-strategists, consistent with the intensified N limitation. In response, dissimilatory nitrate reduction to ammonium (DNRA) rates increased while nitrous oxide (NO) production reduced suggesting more efficient N utilization in MPs treatments. The MPs with heteroatoms such as PLA- and PVC-MPs, increased DNRA rates by 67.5-78.7%, exhibiting a stronger impact than PE-MPs. The variation partitioning analysis revealed that the variances of DNRA rates and NO production could be attributed to synergistic effects of physicochemical properties, nutrient limitation, and microbial community in mangrove sediments. Overall, this study provides pertinent insights into the impacts of MPs as a new carbon source on nutrient limitation and N turnover in mangrove ecosystems.
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http://dx.doi.org/10.1016/j.envint.2024.108546 | DOI Listing |
Microorganisms
December 2024
Pinglu Canal and Beibu Gulf Coastal Ecosystem Observation and Research Station of Guangxi, Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, College of Marine Sciences, Beibu Gulf University, Qinzhou 535011, China.
Mangroves, as blue carbon reservoirs, provide a unique habitat for supporting a variety of microorganisms. Among these, bacteria play crucial roles in the biogeochemical processes of mangrove sediments. However, little is known about their community composition, spatial distribution patterns, and environmental driving factors, particularly across the large geographical scales of mangrove wetlands.
View Article and Find Full Text PDFBiology (Basel)
December 2024
Department of Earth Sciences, NOVA School of Science and Technology, GEOBIOTEC, Campus de Caparica, 2829-516 Caparica, Portugal.
On the African continent, Picrodendraceae are represented by four genera. Their intracontinental paleophytogeographic histories and paleoecological aspects are obscured by the lack of pre-Miocene fossils. For this study, late Eocene sediments from Kenya were investigated.
View Article and Find Full Text PDFNPJ Biofilms Microbiomes
January 2025
School of Environmental Science and Engineering, Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), State Key Laboratory for Biocontrol, Sun Yat-sen University, 510006, Guangzhou, China.
Mangrove ecosystems are globally recognized for their blue carbon (C) sequestration capacity. Lignocellulosic detritus constitutes the primary C input to mangrove sediments, but the microbial processes involved in its bioprocessing remain unclear. Using lignocellulosic analysis and metagenomic sequencing across five 100-cm sediment cores, we found a high proportion of lignin (95.
View Article and Find Full Text PDFGlob Chang Biol
January 2025
Department of Biology, University of Southern Denmark, Odense, Denmark.
The concept of "blue carbon" is, in this study, critically evaluated with respect to its definitions, measuring approaches, and time scales. Blue carbon deposited in ocean sediments can only counteract anthropogenic greenhouse gas (GHG) emissions if stored on a long-term basis. The focus here is on the coastal blue carbon ecosystems (BCEs), mangrove forests, saltmarshes, and seagrass meadows due to their high primary production and large carbon stocks.
View Article and Find Full Text PDFSci Total Environ
January 2025
College of Environmental Science and Engineering, Tongji University, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai 200092, China; Frontiers Science Center for Intelligent Autonomous Systems, Shanghai 200092, China; Institute of Carbon Neutrality, Tongji University, Shanghai 200092, China. Electronic address:
Mangrove ecosystems, a type of blue carbon ecosystems (BCEs), are vital to the global carbon cycle. However, the combined effects of microplastics (MPs) and plastic additives on carbon sequestration (CS) in mangroves remain unclear. Here, we comprehensively review the sources, occurrence, and environmental behaviors of MPs and representative plastic additives in mangrove ecosystems, including flame retardants, such as polybrominated diphenyl ethers (PBDEs), and plasticizers, such as phthalate esters (PAEs).
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