Why is biogeochemical cycles sustainable

Where agricultural land is also drained these effects can be magnified. Urbanization also accelerates streamflow by preventing precipitation from filtering into the soil and shunting it into drainage systems.

Additional physical infrastructure has been added to river networks with the aim of altering the volume, timing, and direction of water flows for human benefit.

This is achieved with reservoirs, weirs, and diversion channels. For example, so much water is removed or redirected from the Colorado River in the western United States that, despite its considerable size, in some years it is dry before reaching the sea in Mexico. We also exploit waterways through their use for navigation, recreation, hydroelectricity generation and waste disposal.

These activities, especially waste disposal, do not necessarily involve removal of water, but do have impacts on water quality and water flow that have negative consequences for the physical and biological properties of aquatic ecosystems. The water cycle is key to the ecosystem service of climate regulation as well as being an essential supporting service that impacts the function of all ecosystems. Consider the widespread impacts on diverse natural and human systems when major droughts or floods occur.

Consequently, human disruptions of the natural water cycle have many undesirable effects and challenge sustainable development. There are two major concerns. First, the need to balance rising human demand with the need to make our water use sustainable by reversing ecosystem damage from excess removal and pollution of water.

Traditionally, considerable emphasis has been on finding and accessing more supply, but the negative environmental impacts of this approach are now appreciated, and improving the efficiency of water use is now a major goal. Second, there is a need for a safe water supply in many parts of the world, which depends on reducing water pollution and improving water treatment facilities.

The vast majority of nitrogen on Earth is held in rocks and plays a minor role in the nitrogen cycle. The second largest pool of nitrogen is in the atmosphere. Most atmospheric nitrogen is in the form of N 2 gas, and most organisms are unable to access it.

This is significant because nitrogen is an essential component of all cells—for instance, in protein, RNA, and DNA—and nitrogen availability frequently limits the productivity of crops and natural vegetation.

Atmospheric nitrogen is made available to plants in two ways. Certain microbes are capable of biological nitrogen fixation , whereby N 2 is converted into ammonium, a form of nitrogen that plants can access. Many of these microbes have formed symbiotic relationships with plants—they live within the plant tissue and use carbon supplied by the plant as an energy source, and in return they share ammonia produced by nitrogen fixation.

Well-known examples of plants that do this are peas and beans. Some microbes that live in the soil are also capable of nitrogen fixation, but many are found in a zone very close to roots, where significant carbon sources are released from the plant. Together these biological nitrogen fixing processes on land, coupled with others that take place at sea, generate an annual flux out of the atmosphere of approximately MtN megatonnnes of nitrogen or ,, tonnes of nitrogen.

Lightning causes nitrogen and oxygen in the atmosphere to react and produce nitrous oxides that fall or are washed out of the atmosphere by rain and into the soil, but the is flux is much smaller 30 MtN per year at most than biological nitrogen fixation. Organic material is matter that comes from once-living organisms.

Ammonification or mineralization is the release of ammonia by decomposers bacteria and fungi when they break down the complex nitrogen compounds in organic material. Plants are able to absorb assimilate this ammonia, as well as nitrates, which are made available by bacterial nitrification. The cycle of nitrogen incorporation in growing plant tissues and nitrogen release by bacteria from decomposing plant tissues is the dominant feature of the nitrogen cycle and occurs very efficiently.

Nitrogen can be lost from the system in three main ways. First, denitrifying bacteria convert nitrates to nitrous oxide or N 2 gases that are released back to the atmosphere. Denitrification occurs when the bacteria grow under oxygen-depleted conditions, and is therefore favored by wet and waterlogged soils. Denitrification rates almost match biological nitrogen fixation rates, with wetlands making the greatest contribution. Second, nitrates are washed out of soil in drainage water leaching and into rivers and the ocean.

Third, nitrogen is also cycled back into the atmosphere when organic material burns. The Nitrogen Cycle. Source: Physical Geography Fundamentals eBook. Humans are primarily dependent on the nitrogen cycle as a supporting ecosystem service for crop and forest productivity. Nitrogen fertilizers are added to enhance the growth of many crops and plantations. Zaehle, G. Billen, P. Boeckx, J. Willem Erisman, J. Garnier, R. Upstill-Goddard, M. Kreuzer, O. Oenema, S.

Reis, M. Schaap, D. Simpson, W. Winiwarter, and M. Sutton , Ch. Sutton, Howard, C. Willem, Billen, G. Carpenter, S. Proceedings of the National Academy of Sciences , , , doi Cavigelli, M. Del Grosso, M. Liebig, C. Snyder, P. Fixen, R. Venterea, A. Leytem, J. McLain, and D. Watts , Ch. Post and Venterea, R. A Report by the U. Climate Change Scie. Climate Change Science Program, pp. Chameides, W. Kasibhatla, J. Yienger, and H. Levy , Growth of continental-scale metro-agro-plexes, regional ozone pollution, and world food production.

Science , , , doi Ciais, P. Canadell, S. Luyssaert, F. Chevallier, A. Shvidenko, Z. Poussi, M. Jonas, P. Peylin, A. King, and E. Schulze , Can we reconcile atmospheric estimates of the Northern terrestrial carbon sink with land-based accounting? Current Opinion in Environmental Sustainability , 2 , , doi Cleveland, C. Townsend , Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere. Cole, J. Prairie, N.

Caraco, W. McDowell, L. Tranvik, R. Striegl, C. Duarte, P. Kortelainen, J. Downing, J. Middelburg, and J. Melack , Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget. Ecosystems , 10 , , doi Davidson, E.

Environmental Research Letters , 7 , , doi Derwent, R. Stevenson, R. Doherty, W. Collins, M. Sanderson, and C. Johnson , Radiative forcing from surface NO x emissions: Spatial and seasonal variations.

Climatic Change , 88 , , doi Dijkstra, F. Prior, G. Runion, H. Torbert, H. Tian, C. Lu, and R. Venterea , Effects of elevated carbon dioxide and increased temperature on methane and nitrous oxide fluxes: Evidence from field experiments.

Frontiers in Ecology and the Environment , 10 , , doi Elser, J. Bracken, E. Cleland, D. Gruner, W. Harpole, H. Hillebrand, J. Ngai, E. Seabloom, J. Shurin, and J. Smith , Global analysis of nitrogen and phosphorus limitation of primary producers in freshwater, marine and terrestrial ecosystems.

Ecology Letters , 10 , , doi Environmental Protection Agency, Washington, D. Greenhouse Gas Emissions and Sinks: — EPA R Greenhouse Gas Emissions and Sinks: Falkowski, P.

Scholes, E. Boyle, J. Canadell, D. Canfield, J. Elser, N. Gruber, K. Hibbard, P. Hogberg, S. Linder, F. Mackenzie, B. Moore, III, T. Pedersen, Y. Rosenthal, S. Seitzinger, V. Smetacek, and W.

Steffen , The global carbon cycle: A test of our knowledge of Earth as a system. Fann, N. Risley , The public health context for PM2. Forster, P. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D. Fahey, J. Haywood, J. Lean, D. Lowe, G. Myhre, J. Nganga, R.

Prinn, G. Raga, M. Schulz, and R. Van Dorland , Ch. Solomon, Qin, D. Galloway, J. Townsend, J. Bekunda, Z. Cai, J. Freney, L. Martinelli, S. Seitzinger, and M. Sutton , Transformation of the nitrogen cycle: Recent trends, questions, and potential solutions. Aber, J. Erisman, S. Seitzinger, R. Howarth, E. Cowling, and B. Cosby , The nitrogen cascade. BioScience , 53 , , doi Gurney, K. Hayes, D. Turner, G. Stinson, A. McGuire, Y. Wei, T. West, L. Heath, B. McConkey, R.

Birdsey, A. Jacobson, D. Huntzinger, Y. Pan, M. Post, and R. Cook , Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data. Global Change Biology , 18 , , doi Houlton, B. How do human activities affect, and how are they affected by, biogeochemical cycles? It is hard to name something in the environment that is not influenced by humans, including biogeochemical cycles.

Climate change is a big concern now and effects of climate change and feedbacks are particularly dramatic in the regions of the permafrost. Herndon et al. One of the biggest concerns is positive feedback on the global warming due to the release of CO 2 and methane, but many other elements, such as P, N, S, and Fe, are affected. Why is there urgency in studying the interconnectedness of different ecosystems? Earth is one system with numerous subsystems that are continuously interacting.

Different ecosystems cannot be fully understood if they are studied in isolation because they are not closed systems. Earth is one system with numerous subsystems such as the biosphere, hydrosphere, atmosphere, and the tectonic system that are continuously interacting.

There is a continuous exchange of materials, energy, and living matter among them and they are all connected through the biogeochemical cycles. To understand complex relationships, processes and feedback loops within landscape evolutions we need to understand how different ecosystems are connected in space and time.

Advertisement Hide. This service is more advanced with JavaScript available. Biogeochemical Cycles in Globalization and Sustainable Development. Authors view affiliations Vladimir F. Krapivin Costas A. Surveys present-day understanding of globalization and sustainable development Provides insight to the social context of global changes in biogeochemical cycles Constructs interactive models of natural and anthropogenic processes, considering the correlation between their components Analyzes regional models to simulate environmental dynamics in the context of globalization and sustainable development Presents relevant results of global ecodynamics simulation modelling Shows land and ocean ecosystems' dynamics in the context of environmental survivability Demonstrates the interactivity of climate change and human strategy in energy use.