Marine ecosystems provide a variety of ecological functions that directly or indirectly translate to economic services and values to humans in the Zhoushan marine area. These ecological functions support fish populations that constitute a significant source of protein, sustain ecosystem stability by conserving biodiversity and mitigating climate change through carbon sequestration, act as sinks for byproducts of industrial or agricultural production, and provide recreational and aesthetic benefits. However, ecosystem services have not been fully recognized or adequately quantified in past accounts of economic or social development. Rapid population growth and human development, such as reclaiming land from the sea and over-exploitation of marine resources, have resulted in degradation of resources, which in turn affects delivery of ecosystem functions and services.
We present a possible approach to using the emergy method (a donor-side approach) by valuing the ecosystem services (a user-side approach). This paper classifies the ecosystem goods and services provided by the Zhoushan marine area into four categories: production services, regulating services, cultural services, and supporting services. We performed this study on the valuation of eight marine ecosystem services: food provision, climate regulation, gas regulation, water quality purification, education and science research, biological control and biodiversity maintenance.
Using the method of emergy analysis, this paper estimated the emergy value of ecosystem services in the Zhoushan marine area. Emergy synthesis is viewed as a "donor-side" evaluation approach because it values items based on energetic inputs, as opposed to consumer preferences. The use of the emergy synthesis method to value ecosystem services provides a stronger basis for management policies as it ensures that the global dynamics of the biosphere are taken into proper account from a "donor-side" perspective. The concept of the "donor-side" is based on the analysis of ecosystems by considering inputs. Emergy synthesis identifies the value of the natural resource in terms of its "donor-side" value. This value then can be used to understand the environmental work needed directly or indirectly to generate a resource, goods, or flow of an economic product.
Ecosystem services are the conditions and processes through which natural ecosystems, and the species that comprise them, sustain and fulfill human life. These "outputs" of the ecosystem provide the goods and services to be directly or indirectly used, or to provide benefits for humans and other species. An ecosystem services approach is a "user-side" approach that has recently been developed and describes ecosystems in terms of their useful outputs. In such "user-side" approaches it is important to define the user, mainly to identify which outputs to consider and the criteria that guide this consideration. Taking this approach, the outputs of systems are related to ecosystem functions, which provide services to be used by humans. This view of the use of ecosystems means that services are valued by means of environmental economic methodologies. These approaches most often assess only non-renewable resources, depending on what human technologies are able to extract from them (a user-side view). In contrast, emergy synthesis is a "donor-side" value approach, and our approach here attempts to combine the two. The calculation of value is related to the work done by ecosystems to produce goods and services that support the economy. The emergy synthesis approach is not an alternative method used to value the ecosystem services. Instead, it is a supplementary and systemic approach to highlight the mechanisms through which services are produced by different systems.
Starting with energy and matter flowing out of an ecosystem (user-side), we present our method in a very schematic way. We use the emergy evaluation (donor-side) approach to quantify marine ecosystems services (output, user-side) in the Zhoushan marine area. The emergy method has been established as a way to properly value ecosystem services. As a "donor-side" approach, the emergy method provides an eco-centric value based on the input that supports a system, rather than the output (ecosystem services) that is useful for humans. The latter approach has been criticized as possibly being erroneous for valuing ecosystem services.
In this paper, the mass or the matter that is related to the ecosystem services (output) was translated to a common unit using the emergy method. The results indicated that the total emergy economic value of ecosystem services in the Zhoushan marine area was 1.1297 Em￥/m². These indicative results from the valuation of a few services in the Zhoushan marine ecosystem suggest that the marine area is of significant importance to humans.