Global climate biogeochemical cycles

It is the determination of volatile organic compounds produced from natural products that requires separation techniques that allow isolation of stereoisomers. The most commonly determined groups are the terpene and sesquiterpene species present in essential oils, which are used as key indicators of biological factors such as the growth season, geographic location, climate, etc. These species are also released directly into the atmosphere by very many plants and trees, and make a substantial contribution to global biogeochemical cycles. 

In addition to biogeochemical cycles (discussed in Section 6.5), the hydrosphere is a major component of many physical cycles, with climate among the most prominent. Water affects the solar radiation budget through albedo (primarily clouds and ice/snow), the terrestrial radiation budget as a strong absorber of terrestrial emissions, and global temperature distribution as the primary transporter of heat in the ocean and atmosphere. 

Aber, J. D. and Driscoll, C. T. (1997). Effects of land use, climate variation, and N deposition on N cycling and C storage in northern hardwood forests, Global Biogeochem. Cycles 11, 639-648. 

Schimel, D. S., Braswell, B. H., McKeown, R., Ojima, D. S., Parton, W. J. and Pulliam, W. (1996). Climate and nitrogen controls on the geography and time-scales of terrestrial biogeochemical cycling. Global Biogeochem. Cycles 10, 677-692. 

Fig. 19-1 Schematic of the processes that connect global biogeochemical cycles and climate. Boxes denote observables and ovals indicate processes that affect these. 

On a global scale, arable lands occupy 12% of the terrestrial ecosystems, and pastures occupy 25%. On the whole, the agrolandscapes occupy 40% of the Earth s land. At present the most used areas are in the moderate climate zone (25%) and subtropical and tropical ones (18%). To the maximal extent, natural landscapes and their relevant biogeochemical cycles are transformed into agrogeochemical provinces with a predominance of agrogeochemical cycles of many elements in Europe (>30%) and Asia (>20%). 

DMSP is a compound that cannot easily be characterized as either a primary or a secondary metabolite because it has primary functions in some organisms and secondary functions in others (Stefels 2000 Steinke et al. 2002 Yoch 2002) in many, if not most of the organisms that produce it, it probably has both. In addition to their physiological and ecological roles, DMSP and DMS are important to global biogeochemical cycling and possibly climate (Malin et al. 1992 Liss et al. 1994 Malin and Kirst 1997 Yoch 2002). 

Considerable evidence exists that human activities have already perturbed parts of the interlinked global biogeochemical cycles of the nutrients, micronutrients, carbon, and O2. Some of these perturbations are the consequence of climate change and others are associated with changes in the rates of input of nutrients and iron to the sea. As... 

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