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The community diversity of phytoplankton is quite high, and hundreds of phytoplankton species can coexist. Aggregating phytoplankton species into different phytoplankton functional groups (PFGs) can better assess and predict the potential structural and functional effects of aquatic ecosystems. The continuous interaction of key PFGs is the key cause of cyanobacterial blooms in drinking water supply systems, especially in shallow border reservoirs, but the reasons have not been understood. This study was carried out in Macau's two shallow border reservoirs, the Main Storage Reservoir (MSR) and Sai Pa Van Reservoir (SPVR). Then, phytoplankton samples from these reservoirs were collected monthly over a four-year period (from January 2011 to December 2014) to reveal key factors driving PFGs succession and their synthetic effects on the dominant species. The trophic state index (TSI) of TN and TP of the two reservoirs ranged from 36.25 to 83.95 and 8.32–56.13, respectively, indicating that the SPVR and MSR were between a eutrophic and hypereutrophic state. The phytoplankton analysis results showed that there were 14 dominant PFGs and 8 dominant PFGs in the MSR and SPVR, respectively. The group S 1 was always predominant in the SPVR during the succession of PFGs, while the succession of PFGs in the MSR were quite different, the PFGs could mainly be summarized as S 1 /S N /X 1 (2011) → X 1 /J/B/T B /P (2012, 2013) →S 1 /X 1 /J (2014). In addition, redundancy analysis (RDA) through stepwise discriminant analysis was used to analyze the dominant PFGs and abiotic factors in both reservoirs. The results indicated that the turbidity value of the reservoir was the key factor influencing groups S 1 , Lo and S N in the SPVR. However, the different PFGs were influenced by the turbidity, NH 3 –N, NO 3 –N and EC values of the reservoir in the MSR. The relationship between PFGs and environmental factors was described by stepwise regression analysis. The investigation of the different ecological responses between the interconnected reservoirs was useful for targeted water source protection. [ABSTRACT FROM AUTHOR]

Water, energy and food (WEF) are closely intertwined. The complex interaction can form the nexus risk due to WEF scarcity. The WEF scarcity nexus risk can cause severe economic losses to adjacent regions through regional trade chains. Investigating the spatial transmission process can help understand regional vulnerability to the WEF scarcity nexus risk. Thus, this research proposes a systematic framework of the WEF scarcity nexus risk monetization method, ecological network analysis (ENA), entropy weight model (EWM) and technique for order preference by similarity to an ideal solution (TOPSIS) to analyze the generation, evolution, transmission and evaluation of WEF scarcity nexus risk. The aims are to intuitively show the harm of WEF scarcity nexus risk through risk monetization and quantitatively analyze WEF scarcity-induced risk spatial transmission. The results indicated that the water-energy-food (W-E-F) scarcity nexus risk was a critical factor restricting regional economic development. Resource-scarce regions/sectors transferred WEF scarcity nexus risk to certain neighboring partners through network trade to ensure local demands. Especially in highly resource-dependent regions (e.g., Guangdong-Hong Kong-Macao region), Hong Kong and Macao would transfer much of the local WEF scarcity nexus risk to Guangdong province, making potential economic losses in Guangdong more significant than local losses. Instead of considering Guangdong, Hong Kong and Macao as competitors, the WEF scarcity nexus risk could be reduced if the three regions worked in a coordinated pattern. Such cooperation has implications for optimizing the industrial structure and sustainable development goals for clean water, affordable energy and food security. [ABSTRACT FROM AUTHOR]