Anthropogenic modification of the nitrogen cycling within the Greater Hangzhou Area system, China.

Based on the mass balance approach, a detailed quantification of nitrogen (N) cycling was constructed for an urban-rural complex system, named the Greater Hangzhou Area (GHA) system, for this paper. The GHA is located in the humid climatic region on the southeastern coast of China, one of the earliest regions in the Yangtze Delta to experience economic development. Total N input into the GHA was calculated at 274.66 Gg/yr (1 Gg = 10(9) g), and total output was calculated at 227.33 Gg/yr, while N accumulation was assessed at 47.33 Gg/yr (17.2% of the total N input). Human activity resulted in 73%of N input by means of synthetic fertilizers, human food, animal feed, imported N containing chemicals, fossil fuel combustion, and other items. More than 69.3% of N was released into the atmosphere, and riverine N export accounted for 22.2% of total N output. N input and output to and from the GHA in 1980 were estimated at 119.53 Gg/yr and 98.30 Gg/yr, respectively, with an increase of 130% and 131%, respectively, during a 24-year period (from 1980 to 2004). The N input increase was influenced by synthetic fertilizers (138%), animal feed (225%), N-containing chemicals (371%), riverine input (311%), and N deposition (441%). Compared to the N balance seen in the arid Central Arizona-Phoenix (CAP) system in the United States, the proportion of N transferred to water bodies in the humid GHA system was found to be 36 times higher than the CAP system. Anthropogenic activity, as it typically does, enhanced the flux of N biogeochemistry in the GHA; however, a lack of an N remover (N pollutant treatment facilities) causes excess reactive N (Nr; such as NH3, N2O, NOx), polluting water bodies and the atmosphere within the GHA. Therefore many challenges remain ahead in order to achieve sustainable development in the rapidly developing GHA system.

[1]  James A. Perry,et al.  Case study for evaluating campus sustainability: nitrogen balance for the University of Minnesota , 2007, Urban Ecosystems.

[2]  Lawrence E. Band,et al.  Effects of Urban Land-Use Change on Biogeochemical Cycles , 2006 .

[3]  Z. Zhu,et al.  Regional nitrogen budgets for China and its major watersheds , 2002 .

[4]  Halla R Sahely,et al.  Estimating the urban metabolism of Canadian cities: Greater Toronto Area case study , 2003 .

[5]  A. Hershey,et al.  Evaluation of denitrification in an urban stream receiving wastewater effluent , 2007 .

[6]  Sareen S. Gropper,et al.  Advanced Nutrition and Human Metabolism , 1990 .

[7]  F. Zhai,et al.  [Study on the current status and trend of food consumption among Chinese population]. , 2005, Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi.

[8]  L. Baker,et al.  Nitrogen Balance for the Central Arizona–Phoenix (CAP) Ecosystem , 2001, Ecosystems.

[9]  J. P. Collins,et al.  A New Urban Ecology , 2000, American Scientist.

[10]  G. Likens,et al.  Technical Report: Human Alteration of the Global Nitrogen Cycle: Sources and Consequences , 1997 .

[11]  M. Feller,et al.  Asymbiotic nitrogen fixation and denitrification in a mature forest in coastal British Columbia , 1989 .

[12]  S. Pickett,et al.  Ecosystem Structure and Function along Urban‐Rural Gradients: An Unexploited Opportunity for Ecology , 1990 .

[13]  Josep G. Canadell,et al.  Terrestrial Ecosystems in a Changing World , 2007 .

[14]  Lawrence E. Band,et al.  Nitrogen Fluxes and Retention in Urban Watershed Ecosystems , 2004, Ecosystems.

[15]  I. Burke,et al.  Carbon fluxes, nitrogen cycling, and soil microbial communities in adjacent urban, native and agricultural ecosystems , 2005 .

[16]  J. Diamond,et al.  China's environment in a globalizing world , 2005, Nature.

[17]  Liangjun Da,et al.  Ecological consequences of rapid urban expansion: Shanghai, China , 2006 .

[18]  Andrew P. Dobson,et al.  Human health effects of a changing global nitrogen cycle , 2003 .

[19]  Albert Koenig,et al.  Escalating Trends in the Urban Metabolism of Hong Kong: 1971–1997 , 2001, Ambio.

[20]  C. Hopkinson,et al.  N Retention in Urbanizing Headwater Catchments , 2005, Ecosystems.

[21]  W. Cao,et al.  Impacts of urbanization on topsoil nutrient balances—a case study at a provincial scale from Fujian, China , 2007 .

[22]  Christopher B. Field,et al.  Nitrogen and Climate Change , 2003, Science.

[23]  José Galizia Tundisi.  Nature Makes a Difference in the City , 2005, Science.

[24]  Amy Luers,et al.  Illustrating the coupled human–environment system for vulnerability analysis: Three case studies , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[25]  J. Thiele,et al.  Urbanization affects stream ecosystem function by altering hydrology, chemistry, and biotic richness. , 2006, Ecological applications : a publication of the Ecological Society of America.

[26]  Min Shao,et al.  City clusters in China: air and surface water pollution , 2006 .

[27]  Louis A. Schipper,et al.  Nitrogen inputs and outputs for New Zealand in 2001 at national and regional scales , 2006 .

[28]  W. McDowell,et al.  Urban influences on the nitrogen cycle in Puerto Rico , 2006 .

[29]  Nancy B. Grimm,et al.  Points, patches, and regions: scaling soil biogeochemical patterns in an urbanized arid ecosystem , 2006 .

[30]  Helmut Rechberger,et al.  Practical handbook of material flow analysis , 2003 .

[31]  E. Athanasopoulou,et al.  Modelling of aerosol in the Greater Athens Area, Greece , 2005 .

[32]  G. Henderson,et al.  Sources, fates, and impacts of nitrogen inputs to terrestrial ecosystems: review and synthesis , 1988 .

[33]  Li Minghong,et al.  Biocycle of nitrogen in a Cyclobalanopsis glauca-dominated evergreen broad-leaved forest in East China , 2006 .

[34]  N. Grimm,et al.  A distinct urban biogeochemistry? , 2006, Trends in ecology & evolution.