Carbon and Energy Balances of Different Ecosystems and Ecosystem Complexes of the Bornhöved Lake District
Energy and carbon cycles of ecosystems and landscapes are closely linked. The main source of energy in ecosystems is solar global radiation. Most of this energy is converted into heat and dissipated by long-wave radiation and convection or is used for the evapotranspiration of water. Only a small fraction of global radiation is used in the process of photosynthesis and changed into chemical energy stored in carbohydrates. Carbon assimilation initiates the biological energy cycle in which most of the carbohydrates produced by photosynthesis is lost by respiration in heterotrophic processes.
In agricultural landscapes parts of the biological energy budget (or carbon budget, respectively) are used for human necessities such as food or fibres. Agricultural landscapes, therefore, should primarily provide society with energy from farm products. However, in addition to local solar radiation today’s agricultural management needs large amounts of energy, for instance for the production of fertilizers or pesticides and finally for field management and transport purposes. In addition, the population of rural areas consumes energy for households and mobility. Therefore the question is whether agricultural landscapes are net producers or net consumers of energy or, in terms of the carbon cycle, are sinks or sources for carbon dioxide and other greenhouse gases. This problem is a central issue for the sustainability of rural areas, and this Chapter explores the abiotic, biotic and anthropogenic carbon and energy budgets of single ecosystems, ecosystem complexes and farms of the Bornhöved Lake District. Finally, the energy balance of the whole region is deduced.
KeywordsSoil Respiration Gross Primary Production Beech Forest Global Radiation Lake District
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