Metaproteomic investigation of sedimentary nitrogen cycling communities responding to seawater intrusion
EMSL Project ID
60695
Abstract
Estuaries are important habitats of diverse biotic communities with high productivity. With the increase of urbanization and land use changes, estuaries have experienced various hydrologic alterations. Estuarine dams are a major anthropogenic disturbance to natural ecosystems converting a brackish flow system into a freshwater reservoir. The Nakdong River in South Korea is an example of an ecosystem heavily impacted by an estuarine dam. In 1987, the Nakdong River Dam was constructed at the mouth of the river to stop tidal seawater exchange and protect freshwater resources. The alteration of flow regimes resulted in consistent seasonal eutrophication over the past 30 years. The Korean government recently developed an innovative plan for water management with controlled openings of the dam gates to restore the natural ecosystem. This system provides an unprecedented opportunity to evaluate the impacts of seawater intrusion on benthic nitrogen cycling communities. A total of 30 Sediment samples were collected before and after the dam gate opening in 2019 and 2020. The sediments were used to examine the changes in abundance, composition, and expression of the nitrogen (N) cycling communities using metagenomic and metaproteomic analyses. Sixteen of the 30 samples were selected for initial metaproteomic analysis at PNNL while all the samples were used for metagenomic analysis at Song’s lab. From the results of both metagenomic and metaproteomic analyses, a significant reduction of the gene abundance in nitrification and denitrification was observed while the DNRA genes were increased with seawater intrusion due to the dam gate opening. Metaproteomic analysis showed differential expression of N cycling genes in the sediments associated with seawater intrusion. Denitrification rates were temporally reduced and matched with metaproteomic data. In order to complete this project, 8 more samples should be analyzed with metaproteomics. This project will be the first multi-omics study showing the significant alternation of N cycling processes due to seawater intrusion in the aquatic ecosystem.
Project Details
Project type
Limited Scope
Start Date
2023-03-13
End Date
2023-07-14
Status
Closed
Released Data Link
Team
Principal Investigator