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In light of the global consensus on low-carbon development and the imperative to reduce greenhouse gas emissions, coupled with China's strategic objective of achieving "carbon neutrality" and reaching its carbon peak, it becomes increasingly essential to focus on areas that necessitate adaptation for low-carbon development. One such critical area is the water supply system, known for its substantial contribution to carbon emissions. To assess the situation, this study constructed an evaluation framework for carbon emissions of water supply system, which comprised of emission characteristic investigation, emission right allocation and right balance assessment. For emission characteristic investigation, data on water supply quantity, pipe network pressure, and energy consumption was utilized to calculate carbon emissions produced by China's water supply system and investigated the spatial and temporal distribution of emissions. The analysis revealed a minor increase in carbon emissions from 2010 to 2018, with a significant turning point occurring in 2016. Specifically, carbon emissions in 2018 ranged between 1.03 × 107 kgCO 2 and 3.15 × 109 kgCO 2. Coastal areas, such as Guangdong and Jiangsu, exhibited a higher level of carbon emissions. This study constructed a provincial allocation model of carbon emission rights, utilizing the shadow price model and entropy method while adhering to the principle of fairness and efficiency. By comparing the value of emission right and emission amount, the provincial balance of carbon emission right in 2018 was evaluated. It was discovered that 14 regions demonstrated varying levels of carbon allowance surpluses. Conversely, 12 regions exhibited insufficient spatial balance, which were subsequently classified as exhibiting mild, moderate, or severe deficiency. Additionally, emission reduction pressures among these regions were assessed through the analysis of the ratio between theoretical emission right and actual amount, as well as levels of economic development. The carbon emission reduction potential scores of different regions were calculated using principal component analysis based on five dimensions, namely policy driver, engineering test and research level, level of economic development, forestry carbon sink and emission reduction efficiency. Our findings indicated that the degree of insufficient balance between emission reduction potential and carbon emission allowance showed a certain convergence. Ultimately, we proposed tailored emission reduction paths for water supply systems in each region, which may serve as theoretical and technical references towards achieving the "double carbon goals". [Display omitted] • Provincial carbon emissions of water supply systems in China were investigated. • An evaluation framework for carbon emissions was constructed. • Shadow price model and entropy method were applied to allocate carbon emission right. • 14 regions showed deficiency in emission right balance, while 12 showed surplus. • Emission reduction potential and degree of deficiency in balance showed convergence. [ABSTRACT FROM AUTHOR]

Coral communities in China's Great Bay Area (GBA) have experienced severe degradation, but only limited information is available about their community structure. We surveyed 20 sites across three regions (Daya Bay, Dapeng Bay, Wanshan Islands) in GBA to provide an updated baseline of these urban coral communities. Live coral cover varied substantially, with the lowest values (<2 %) found inside the highly urbanized Daya Bay, and highest values (40–47 %) from offshore islands that are less affected by human activities. The two sites with the lowest live coral cover had a high percentage of dead coral. Five groups of coral communities could be identified, with most of them characterized by dominance of massive and encrusting coral species. Both coral cover and generic richness were negatively correlated with dissolved inorganic nitrogen in the water column, indicating that nutrient pollution could potentially constrain the development of these urban coral communities. • We aimed to provide a baseline of coral communities along the coasts of Guangdong, China. • We surveyed 20 sites across Daya Bay, Dapeng Bay, and Wanshan Islands. • Live coral cover varied substantially from 1.3 % to 46.5 %. • Most sites were dominated by massive and encrusting coral species. • Coral cover and generic richness were negatively correlated with dissolved inorganic nitrogen. [ABSTRACT FROM AUTHOR]

In 1973 planorbid snails then identified as Biomphalaria straminea were discovered in Hong Kong, China. It was assumed that these snails had been introduced to Hong Kong via the import of tropical fish by air from South America. In 2012 Biomphalaria were found for the first time in Guangdong Province, China. In view of the renewed interest in these invasive snails, a morphological and DNA-sequence based phylogenetic study was undertaken for seven populations of Biomphalaria snails collected in Guangdong. Morphologically and phylogenetically, five of the populations clustered more closely with Biomphalaria kuhniana than with B. straminea. Levels of genetic diversity among the populations were about half those of autochthonous populations in Brazil, the phylogenetic relationships did not correlate with a radiation from any one international port in China, and different lineages appeared associated with different ports. Consequently in explaining the current distribution of the snails, multiple colonization events, each establishing a new local snail population near to maritime international container ports, were considered more likely than the spread of snails from Hong Kong to China. The displacement of B. straminea by B. kuhniana in Guangdong is considered as an explanation for the habitat changes observed among the snails between Hong Kong in the 1980s and the present. The conclusions of the study are that any risk of Schistosoma mansoni transmission in China is more likely to come from parasite importation in the intramolluscan stage, than from transmission by migrant workers from South America or Africa. In addition, although likely to be rare, sporadic outbreaks of imported schistosomiasis (caused by invading infected snails) could be a threat to public health in the vicinity of International container ports (not only in Guangdong Province). Further work is called for to investigate further the presence of B. kuhniana and its potential interactions with B. straminea (the former is thought to be incompatible with S. mansoni ), and the responses of Chinese Biomphalaria to potential competitors such as Thiaridae. The current expansion of container ports in Brazil and Venezuela, and the increase in trade with China, is likely to accentuate any current risk of imported schistosomiasis, and surveillance around ports in China, together with further research, are necessary. [ABSTRACT FROM AUTHOR]