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1. High Resolution Modeling of River‐Floodplain‐Reservoir Inundation Dynamics in the Mekong River Basin

   https://doi.org/10.1029/2019WR026449  

   Shin, Sanghoon ; Pokhrel, Yadu ; Yamazaki, Dai ; Huang, Xiaodong ; Torbick, Nathan ; Qi, Jiaguo ; Pattanakiat, Sura ; Ngo‐Duc, Thanh ; Nguyen, Tuan Duc ( April 2020 , Water Resources Research)

   Numerous studies have examined the changes in streamflow in the Mekong River Basin (MRB) using observations and hydrological modeling; however, there is a lack of integrated modeling studies that explicitly simulate the natural and human‐induced changes in flood dynamics over the entire basin. Here we simulate the river‐floodplain‐reservoir inundation dynamics over the MRB for 1979–2016 period using a newly integrated, high‐resolution (~5 km) river hydrodynamics‐reservoir operation model. The framework is based on the river‐floodplain hydrodynamic model CaMa‐Flood in which a new reservoir operation scheme is incorporated by including 86 existing MRB dams. The simulated flood extent is downscaled to a higher resolution (~90 m) to investigate fine‐scale inundation dynamics, and results are validated with ground‐ and satellite‐based observations. It is found that the historical variations in surface water storage have been governed primarily by climate variability; the impacts of dams on river‐floodplain hydrodynamics were marginal until 2009. However, results indicate that the dam impacts increased noticeably in 2010 when the basin‐wide storage capacity doubled due to the construction of new mega dams. Further, results suggest that the future flood dynamics in the MRB would be considerably different than in the past even without climate change and additional dams. However, it is also found that the impacts of dams can largely vary depending on reservoir operation strategies. This study is expected to provide the basis for high‐resolution river‐floodplain‐reservoir modeling for a holistic assessment of the impacts of dams and climate change on the floodpulse‐dependent hydro‐ecological systems in the MRB and other global regions.

    

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2. Population dynamics, delta vulnerability and environmental change: comparison of the Mekong, Ganges–Brahmaputra and Amazon delta regions

   https://doi.org/10.1007/s11625-016-0372-6  

   Szabo, Sylvia ; Brondizio, Eduardo ; Renaud, Fabrice G. ; Hetrick, Scott ; Nicholls, Robert J. ; Matthews, Zoe ; Tessler, Zachary ; Tejedor, Alejandro ; Sebesvari, Zita ; Foufoula-Georgiou, Efi ; et al ( July 2016 , Sustainability Science)
3. Maintaining perspective of ongoing environmental change in the Mekong floodplains

   https://doi.org/10.1016/j.cosust.2019.01.002  

   Arias, Mauricio E ; Holtgrieve, Gordon W ; Ngor, Peng Bun ; Dang, Thanh Duc ; Piman, Thanapon ( April 2019 , Current Opinion in Environmental Sustainability)
4. A synthesis of hydroclimatic, ecological, and socioeconomic data for transdisciplinary research in the Mekong

   https://doi.org/10.1038/s41597-023-02193-0  

   Tiwari, Amar Deep ; Pokhrel, Yadu ; Kramer, Daniel ; Akhter, Tanjila ; Tang, Qiuhong ; Liu, Junguo ; Qi, Jiaguo ; Loc, Ho Huu ; Lakshmi, Venkataraman ( December 2023 , Scientific Data)

   Abstract The Mekong River basin (MRB) is a transboundary basin that supports livelihoods of over 70 million inhabitants and diverse terrestrial-aquatic ecosystems. This critical lifeline for people and ecosystems is under transformation due to climatic stressors and human activities (e.g., land use change and dam construction). Thus, there is an urgent need to better understand the changing hydrological and ecological systems in the MRB and develop improved adaptation strategies. This, however, is hampered partly by lack of sufficient, reliable, and accessible observational data across the basin. Here, we fill this long-standing gap for MRB by synthesizing climate, hydrological, ecological, and socioeconomic data from various disparate sources. The data— including groundwater records digitized from the literature—provide crucial insights into surface water systems, groundwater dynamics, land use patterns, and socioeconomic changes. The analyses presented also shed light on uncertainties associated with various datasets and the most appropriate choices. These datasets are expected to advance socio-hydrological research and inform science-based management decisions and policymaking for sustainable food-energy-water, livelihood, and ecological systems in the MRB. 

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5. A Global Survey of Hypervirulent Aeromonas hydrophila (vAh) Identified vAh Strains in the Lower Mekong River Basin and Diverse Opportunistic Pathogens from Farmed Fish and Other Environmental Sources

   https://doi.org/10.1128/spectrum.03705-22  

   Xu, Tingbi ; Rasmussen-Ivey, Cody R. ; Moen, Francesco S. ; Fernández-Bravo, Ana ; Lamy, Brigitte ; Beaz-Hidalgo, Roxana ; Khan, Chan Dara ; Castro Escarpulli, Graciela ; Yasin, Ina Salwany ; Figueras, Maria J. ; et al ( April 2023 , Microbiology Spectrum)

   Iwanowicz, Luke R. (Ed.)

   ABSTRACT Hypervirulent Aeromonas hydrophila (vAh) has emerged as the etiologic agent of epidemic outbreaks of motile Aeromonas septicemia (MAS) in high-density aquaculture of farmed carp in China and catfish in the United States, which has caused millions of tons of lost fish. We conducted a global survey to better understand the evolution, geographical distribution, and phylogeny of vAh. Aeromonas isolates were isolated from fish that showed clinical symptoms of MAS, and pure cultures were screened for the ability to utilize myo -inositol as the sole carbon source. A total of 113 myo- inositol-utilizing bacterial strains were included in this study, including additional strains obtained from previously published culture collections. Based on a gyrB phylogeny, this collection included 66 A. hydrophila isolates, 48 of which were vAh. This collection also included five new vAh isolates from diseased Pangas catfish ( Pangasius pangasius ) and striped catfish ( Pangasianodon hypophthalmus ) obtained in Cambodia and Vietnam, respectively. Genome sequences were generated from representative vAh and non-vAh isolates to evaluate the potential for lateral genetic transfer of the myo- inositol catabolism pathway. Phylogenetic analyses of each of the nine genes required for myo -inositol utilization revealed the close affiliation of vAh strains regardless of geographic origin and suggested lateral genetic transfer of this catabolic pathway from an Enterobacter species. Prediction of virulence factors was conducted to determine differences between vAh and non-vAh strains in terms of virulence and secretion systems. Core genome phylogenetic analyses on vAh isolates and Aeromonas spp. disease isolates (55 in total) were conducted to evaluate the evolutionary relationships among vAh and other Aeromonas sp. isolates, which supported the clonal nature of vAh isolates. IMPORTANCE This global survey of vAh brought together scientists that study fish disease to evaluate the evolution, geographical distribution, phylogeny, and hosts of vAh and other Aeromonas sp. isolates. In addition to vAh isolates from China and the United States, four new vAh isolates were isolated from the lower Mekong River basin in Cambodia and Vietnam, indicating the significant threat of vAh to modern aquaculture and the need for improved biosecurity to prevent vAh spread. 

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