Emergy Analysis And Life Cycle Assessment Of Land-based Sea Cucumber Farming Systems

1. Development status of A. japonicas farming in north China and its majorfarming patternsBased on the summary of the current status of A. japonicas farming in north China,the economic and ecological significance of the development of A. japonicasaquaculture were analized. Intensive, semi-intensive and extensive farming systems ofA. japonicas were introduced. Then the comparison was made amoung these threefarming systems of sea cucumber in aspects of infrastructure construction, feedingand farming management.2. Sustainability evaluation of different systems for A. japonicas farming basedon emergy theoryEmergy analysis approach is an effective tool for analyzing ecological economicsystems; however, the accuracy of the approach is affected by the diversity of theeconomic level, meteorological and hydrological parameters in different regions. Thepresent study evaluated the economic benefits, environmental impact, andsustainability of indoor, semi-intensive, and extensive farming systems of seacucumber in the same region. The results showed that:(1) The A. japonicus indoorfarming system was a high input and high yield farming pattern, whereas the pondextensive farming system was a low input and low output pattern.(2) The outputinput ratio of the indoor farming system was lower than that of the extensive farmingsystem, and the output input ratio of the semi-intensive farming system fell in thebetween. The environmental loading ratio of the A. japonicus extensive farmingsystem was lower than that of the indoor farming system. In addition, the emergyyield ratio, emergy exchange ratio, emergy sustainability index and emergy index forsustainable development were higher in the extensive farming system than those inthe indoor farming system. These results indicated that the current extensive farming system exerted fewer negative influences on the environment, made more efficientuse of available resources, and met more sustainable development requirements thanthe indoor farming system.(3) A. japonicus farming systems showed more emergybenefits than fish farming systems. The pond farming systems of A. japonicusexploited more free local environmental resources for production, caused lesspotential pressure on the local environment, and achieved higher sustainability.3. Life cycle assessment of different systems for A. japonicas farmingThe Life Cycle Assessment was employed to evaluate the environmental impactson three farming systems (indoor intensive, semi-intensive and extensive systems) forsea cucumber located near Qingdao, China, which effectively avoids backgroundimpacts caused by such parameters as unbalanced economic levels and varyinggeographic environment. Six indicators entailing Global Warming Potential(1.86E+04,3.45E+03,2.36E+02), Eutrophication Potential (6.65E+01,-1.24E+02,-1.65E+02), Acidification Potential (1.93E+02,4.33E+01,1.30E+00), PhotochemicalOxidant Formation Potential (2.35E-01,5.46E-02,2.53E-03), Human ToxicityPotential (2.47E+00,6.08E-01,4.91E+00) and Energy Use (3.36E+05,1.27E+04,1.48E+03) were introduced in the current study. It was found that owe to the leadingrole of energy inputs, all environmental indicators in the indoor intensive farmingsystem were much higher than those in semi-intensive and extensive farming systems;While energy inputs also contributed to be the leading cause factor for most of theindicators in the semi-intensive farming system; Yet in the extensive farming system,infrastructure materials played a major role. It was concluded, through acomprehensive comparison of the three farming systems, that income per unit area ofindoor intensive farming system was much higher than those of semi-intensive andextensive farming systems. But the extensive farming system appeared to be the mostsustainable one in the assessment. Moreover, adequate measures were proposedrespectively to improve the environmental sustainability of each farming system inthe present study. 4. Carbon footprints of different systems for Apostichopus japonicas farmingbased life cycle assessmentThe carbon footprint calculation method of three farming systems (intensive,semi-intensive and extensive systems) for Apostichopus japonicas located nearQingdao, China was put forward. Carbon emission (kg CO2-eq) for the production of1t sea cucumber from the three farming systems were quantized and compared.Major influence factors of the carbon footprint were analyzed. The results showed that:the entire carbon emission for the production of1t sea cucumber from the threefarming systems were38887.78,9024.41and269.96kg CO2-eq. Carbon emission ofelectricity contributed to be the leading cause factor for carbon footprint of intensive(78.7%) and semi-intensive (96.9%) farming systems. Yet in the extensive farmingsystem, carbon emission of polyethylene played a major role (69.6%). The pondfarming systems of A. japonicus achieved higher sustainability than indoor intensivefarming system on the perspective of carbon footprint. Moreover, adequate measureswere proposed respectively to reduce carbon emissions of each farming system in thepresent study.