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Urban phosphorus metabolism is of particular importance due to the global scarcity of phosphorus,food security of residents,and potential impacts on urban environment and peri-urban ecosystems.The world is rapidly urbanizing with significant changes in living standards,including the quantity,quality and structure of daily food consumed.As a result,urban phosphorus metabolism through food consumption,which is an important process of the metabolism,has been significantly impacted. The purpose of this study is to analyze the variation in food phosphorus consumption by Xiamen residents,its environmental loads in 1988—2010,and to examine the associated economic and social factors by using the Spearman correlation analysis.The key stocks and flows of phosphorus through food consumption were explored using a material flow analysis(MFA) approach to develop a conceptual model of phosphorus flow for urban food consumption. The results showed that there was a fluctuating growth in the total food phosphorus consumption,reached 1,128.88 t in 2010 because of the resident population boom;and the dynamic change in per capita phosphorus consumption varied between 315 g and 380 g,showed an M-shape with the two modes in 1998 and 2003.In addition,high phosphorus food increased sharply.For example,dairy products and aquatic products accounted for 0.3% and 6.8% of the per capita phosphorus consumption,respectively,in 1988,but the proportion reached 14.9% and 15.5%,respectively,in 2010. The results of the correlation analysis showed that there was a significant positive correlation between per capita phosphorus consumption in grain and the Engel coefficient,as well as the average number of people in the family.However,there was a significant negative correlation with per capita disposable income,the food price index and the proportion of college graduates.The correlation between per capita phosphorus consumption in other kinds of food,such as plant oil,fruits,meat,eggs,dairy products and aquatic products,and these factors was opposite.The correlations were significant negative between these kinds of food and the former group of socio-economic factors,but with the latter group of socio-economic factors the correlations were significant positive.The variation of food phosphorus consumption was not significantly correlated with these socio-economic factors,so these socio-economic factors mainly exerted their influence on per capita phosphorus consumption in all kinds of food. As the total food phosphorus consumption increased,the environmental load of phosphorus from food leaped,the value in 2010 tripled over that in 1991.The proportion of phosphorus in the soil significantly increased from 59.7% to 85.1%,which partly due to a growing amount of kitchen waste and the landfilled sludge.Since the phosphorus mainly remained in soil and water,the proportion of phosphorus in the water decreased accordingly.Other factors which may have influenced the results are including a prohibition of phosphorus on detergents,and improvements in wastewater treatment.Thus,it has become the most important mission to develop and implement efficient strategies to facilitate phosphorus recycling.Relevant solutions for improving phosphorus recycling efficiency should be studied in the future to establish a strong coordination between urban and peri-urban areas for nutrient recycling to attain sustainable development.

While actions for addressing global climate change should not be delayed,an open and compatible method for quantifying the greenhouse gas(GHG) emissions of cities or local regions is critical required to support policies.Urban GHG inventory is fundamental for accounting GHG emissions in cities.In general,it reflects both emission structure and trend.Compiling GHG inventories at urban scale is a basic demand of low-carbon city construction in China,and also a foundation for China′s future development. Although use the methods of national GHG inventories as reference,GHG inventories for cities have their own characteristics on principles and methodology systems.The present urban GHG inventory usually uses the experiences of GHG inventory methodologies developed by IPCC(The Intergovernmental Panel on Climate Change),ICLEI(International Council for Local Environmental Initiatives) and Draft International Standard for Determining Greenhouse Gas Emissions for Cities.However,there are still no systemic and standardized methods and indexes for urban GHG inventories,because different organizations have established different approaches for inventorying urban GHG emissions.Though unified framework,such as IPCC or ICLEI,is used,treatments on some emission sources(electricity and cross-boundary transport) or divisions of sub-sectors are different.Due to these issues,it is unsuitable for comparison between cities.At the same time,the calculation results of China′s urban GHG emissions have little comparability with those of western cities,owing to differences of definitions and scales. China′s urban GHG emission inventory research is just at the beginning and achievements need to be extended and the performance of urban GHG emission inventory still has a long way to go.Based on present methodologies of compiling urban GHG emission inventories and typical case studies,both domestic and international,we were willing to establish a common standard by which inventory of urban emissions should be followed.Considering the special characteristics of China′s urban structure,and the problems which would be faced during the accounting progress,China′s urban GHG inventories should take its administrative area as spatial boundary and three main gases,carbon dioxide,methane and nitrous oxide,should be concluded.Consumption-based mode should be chose in order to reflect emission amount and structure more truly and more comprehensive.The most recent IPCC guidelines can be used for determining emissions from four aspects,energy(stationary and mobile sources),industrial processes and product use(IPPU),agriculture,forestry and other land use(AFOLU;where significant),and waste.While it is impractical to quantify all of the emissions associated with the indirect ways of urban GHG emissions,such as myriad of goods and materials consumed in cities,urban GHG inventories should also include out-of-boundary emissions from the generation of electricity and district heating which are consumed in cities(including transmission and distribution losses),emissions from aviation and marine vessels carrying passengers or freight away from cities,out-of-boundary emissions from waste that is generated in cities.The GHG emissions embodied in the food,water,fuels and building materials consumed in cities should also be reported as additional information items if possible.Uncertainty assessment and quality assurance are encouraged and should follow IPCC guidelines.

Cities are centers of political,economic,cultural and social life.It is a symbol of human civilization and development,and urbanization is a common trend in many countries.Nowadays,world urbanization accelerates greatly,especially in developing countries.While providing great economic and social benefits,urbanization has also created some environmental problems,including the Urban Heat Island(UHI) effect.UHI has deep impacts on material cycles and energy transfers within urban ecosystems,and has become an important issue in urban climate and environmental research.Xiamen is one of the special economic zones,and its rapid urbanization induced the UHI becoming much more intense and extensive.To study UHI from a viewpoint of landscape is a new method in urban thermal environment research.Analyzing the dynamics of the urban thermal landscape in the context of urbanization will provide support for environmental protection,energy use policy making,and urban planning and management. This study analyzed the spatiotemporal changes of urban thermal landscape pattern in the main area of Xiamen City.Firstly,Landsat Thematic Mapper(TM) and Enhanced Thematic Mapper Plus(ETM+) thermal images,which were acquired on similar dates in the winter of 1987,1992,1997,2002 and 2007,were used to retrieve brightness temperature.Then a relative brightness temperature(R) was calculated and the thermal patches were classified into 6 grades by temperature difference.Landscape metrics were used here at both landscape and class level to quantify changes in the urban thermal landscape pattern.And they can describe the changes of thermal landscape pattern in 3 aspects,including quantity,shape and structure.Finally,we investigated the distribution of thermal pollution sources in Xiamen. The results showed that: 1) In terms of quantity,with the rapid urbanization of Xiamen City between 1987 and 2007,the thermal landscape became more fragmented,and was more and more dominated by high-grade thermal landscape patches.2) The shape of high-grade thermal patches even the whole landscape tends to complex.3) For structure,each grade of thermal landscape became well-distributed and even.The new high-grade thermal patches were found close to the old ones that induced the proximity index(PROX_MN) of high-grade thermal patches increased;the aggregation index(AI) of the whole landscape decreased while the high-grade thermal patches increased;the contagion index(CONTAG) of the whole landscape also decreased so that dominance of high-grade thermal patches gradually increased.4) The area of thermal patches which converted from low-grade to high-grade is bigger than the area converted from high-grade to low-grade.According to statistical analysis,we found that it is much easier that the high-grade thermal landscape patches converted into the middle-grade thermal landscape than converted among high grades.5) The high-grade thermal patches mainly distributed in the industry area,and they were increased remarkably.All the high-grade thermal patches experienced three kinds of changes(increasing number,expanding area and increasing grade),and grouped into five high temperature zones(Haicang,Xinyang,Xinglin,seaport of Xiamen island and airport),especially in the industrial districts of Xinyang and Xinglin.