Biogeochemical cycles anthropogenic effects

Feedbacks may be affected directly by atmospheric CO2, as in the case of possible CO2 fertilization of terrestrial production, or indirectly through the effects of atmospheric CO2 on climate. Furthermore, feedbacks between the carbon cycle and other anthropogenically altered biogeochemical cycles (e.g., nitrogen, phosphorus, and sulfur) may affect atmospheric CO2. If the creation or alteration of feedbacks have strong effects on the magnitudes of carbon cycle fluxes, then projections, made without consideration of these feedbacks and their potential for changing carbon cycle processes, will produce incorrect estimates of future concentrations of atmospheric CO2. 

Kortzinger A. and Quay P. (2003) Relationdiip between anthropogenic CO2 and the Seuss effect in the North Atlantic Ocean. Global Biogeochem. Cycles 17(1), 1005. 

Small catchments with similar soil and climate conditions and similar anthropogenic loading are most suitable for investigation of biogeochemical cycles in agroecosystems. The small catchment concept is widely used in European studies to evaluate the effects of different soil types, crops and management strategies on... 

The calculation of atmospheric budgets allows us to obtain a general idea on the effect of anthropogenic activity on the environmental biogeochemical cycle of lead in European domain. These calculations include the air reservoir over European domain, 37.5 X 10 km and 4 km height (Table 29). 

The four chapters within the Chemistry section discuss the effects of UVR on biogeochemical cycles of various elements (Chapter 5), the photochemistry of DOM (Chapter 6), the photo-activated toxicity of several natural and anthropogenic substances (Chapter 7) and the environmental implications of photoinduced formation of reactive oxygen species (Chapter 8). Once again, the central role of DOM emerges as a unifying theme. 

In this book air chemistry is defined as a branch of atmospheric science dealing with the atmospheric part of the biogeochemical cycle of different constituents. In other words this means that we will deal mainly with the atmospheric pathways of those components that are involved in the mass flow between the atmosphere and biosphere, as well as in chemical interactions between the air and the other media of our environment (soils, oceans etc.). It follows from this definition that, on the one hand, our discussion will be restricted to the troposphere and the stratosphere4 and, on the other hand, the photochemistry of the upper layers, the subject matter of the aeronomy (e.g. Nicolet, 1964), will be omitted. This separation of the (photo) chemistry of the lower (troposphere and stratosphere) and upper atmosphere makes it possible to give a more compact treatment of our problem, including the global anthropogenic effects due to the increase of air pollution. 

Pongratz J, Reick CH, Raddatz T, Claussen M. Effects of anthropogenic land cover change on the carbon cycle in the last millennium. Glob Biogeochem Cycles 2009 23. 

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