Nutrient Cycling

Dysfunctions in nutrient cycling

, leading, for example, to eutrophication, or climate change, have severe negative effects on life, that is, biodiversity, on Earth.

Unlike energy, nutrients ?

, nutrients do not enter or exit from the earth: they cycle

. Three processes dictate the increased flows of N in the global cycle.

. First, industrial-era combustion, especially of fossil fuels, has increased the emission of reactive N gases to the atmosphere. Worldwide deposition of N as wet or dry deposits, in the form of NO2 or NH4 ions, is especially concentrated in regions with farm cattle production, stimulating net primary productivity (since N is the most widely limiting nutrient in terrestrial ecosystems). Once the N-saturation point of the recipient ecosystem is reached, the excess is leached into adjacent rivers, lakes, and coastal zones, causing eutrophication (leading to major biodiversity loss). Second, the industrial conversion of atmospheric N2 to ammonia laid the foundation for the exponential growth in N fertilizer use in the second half of the twentieth century, enabling the high-yielding crops of the Green Revolution. Third, the natural process of biological N fixation has been harnessed for agricultural purposes. Worldwide plantings of N-fixing crops, such as soybeans, now capture of a huge amounts of nitrogen

Nutrient cycle

: A nutrient cycle is the path of an element from one organism to another and from organisms into the nonliving part of the biosphere and back. Nutrient cycles are sometimes referred to as biogeochemical cycles, reflecting the fact that chemicals are cycled between biological organisms and between organisms and the geologic (physical) environment.

Greenhouse gases

: Rising concentration of greenhouse gases in the atmosphere, which block heat from escaping to space, has contributed to global temperature rise in modern time. The scientific consensus on climate change today is that climate is changing and that it is caused by human activities. Earth's surface absorbs heat from the sun and then re-radiates it back into the atmosphere and to space. Much of this heat is absorbed by greenhouse gases. Though only 1% of atmospheric gases are greenhouse gases, they are extremely powerful heat trappers.

Methane (CH4):

A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one which is much less abundant in the atmosphere.

Nitrous oxide (N2O

A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.

Climate change and environment

A warming planet means continuing changes in most ecosystems -- in oceans and lands alike. Sea life has been much impacted recently, for instance, the change in temperature has caused a massive loss of algae in corals which appear white (coral bleaching). The result is the mass death of sea animals dependent on the coral reef. Carbon dioxide acidifies seawater as more CO2 is dissolved in the ocean. CO2 and carbonate (which plankton use to make shells) combine in the ocean making it acidic which put many sea creatures at risk Temperature changes impact the lifecycle events (migration reproduction) of some species, mosquitoes birds insects. Snow and ice are melting, then number of glaciers have been reduced from 150 to 26 in 164 years (in Glacier NAtional Park) If glaciers keep melting, the world sea level will rise, inundating many coastal cities.

comparison of carbon dioxide emissions by different nations

Although the United States (on top of the list) make up only 4% of the world's total population, produced nearly 25% of the world's greenhouse gases. In comparison, India, with over 1 billion people (~17% of the world's population), was responsible for 2% of carbon dioxide emissions China is the worlds number 1 emitter of CO2 and other greenhouse gases.

Climate change and health

As temperatures get milder, mosquitoes, ticks, rodents, and other disease carriers will expand their range summers will get hotter, not only because of higher temperatures but also because humidity will increase. That means that heat waves, like the one that killed 35,000 people in Europe in 2003, will become more common.

Variations in solar radiation

Both long- and short-term variations in solar intensity are known to affect global climate. Solar output also varies on shorter time scales, including the 11-year solar cycle, that triggered the Little Ice Age (from 1550 to 1850) and some of the warming observed from 1900 to 1950. The cyclical nature of the sun's energy output, as the sun ages and evolves, is, however, not yet fully understood.

Carbon cycle:

Carbon enters the living things through photosynthesis and leaves via respiration, during the fast phase of carbon cycle. Most of Earth's carbon is stored in rocks. The rest is in the ocean, atmosphere, plants, soil, and fossil fuels. Carbon flows between each of these reservoirs in an exchange called the carbon cycle. Any change in the cycle that shifts carbon out of one reservoir puts more carbon in the other reservoirs. Changes that put carbon gases into the atmosphere result in warmer temperatures on Earth. Over the long term, the carbon cycle seems to maintain a balance that prevents all of Earth's carbon from entering the atmosphere (as is the case on Venus) or from being stored entirely in rocks. This balance helps keep Earth's temperature relatively stable, like a thermostat. Marine Sediments and Sedimentary Rocks - 100,000,000 billions of metric tons

The effect of climate change due to global warming

Climate change and environment Climate change and health Climate change and overall economy

Five most important greenhouse gases include:

Methane (CH4) Nitrous oxide (N2O) Chlorofluorocarbons (CFCs) Carbon Dioxide (CO2)

Nitrogen cycle

Nitrogen cycle is the continuous flow of nitrogen through the biosphere by the processes of nitrogen fixation, ammonification (decay), nitrification, and de-nitrification. earth's atmosphere is 78% nitrogen, free gaseous nitrogen cannot be utilized by animals or by higher plants. To enter living systems, nitrogen must be "fixed" (combined with oxygen or hydrogen) into compounds (such as nitrates) that plants can utilize bulk fixation is performed by soil bacteria of two kinds -- those that live free in the soil and those that live enclosed in nodules in the roots of certain leguminous plants (e.g., alfalfa, peas, soybeans).

Soluble and insoluble forms

Nutrients enter water as soluble salts (salt state), and accumulation of salts, silts, etc. to become rock (rock state) which is non-soluble.

Plate tectonics

Over millions of years, the motion of tectonic plates reconfigures global land and ocean areas and generates topography. This can affect both global and local patterns of climate and atmosphere-ocean circulation. For instance, Isthmus of Panama, which was formed about 5 million years ago, shut off direct mixing between the Atlantic and Pacific Oceans, affecting the ocean dynamics of what is now the Gulf Stream and may also have led to Northern Hemisphere ice cover.

Phosphorus cycle

Phosphorus moves slowly from deposits on land and in sediments, to living organisms, and then much more slowly back into the soil and water sediment. Phosphorus cycle is the slowest of all nutrient cycles. The lithosphere is the ultimate source of all phosphorus in the biosphere. While apatite (the naturally occurring phosphate rock) is one of the most easily weathered primary minerals, P is amongst the least biologically available major nutrients. This is because the forms of phosphorus in the biosphere are poorly soluble, immobile, or otherwise inaccessible. P often co-limits (with N) plant and animal production on old, highly weathered soils, such as those that dominate tropical Africa, South America, and Australia. Since NH4 and NO3 are both more readily leached out of soils than phosphate, freshwater and some coastal ecosystems are typically more responsive to increases of P than of N, making P the principal driver of eutrophication in lakes and estuaries.

flow of energy

Plants convert that energy to sugar and cellulose. Grazing animals forage plants, lose some of the energy, and store some as protein and fat - both a form of energy. Animals, while foraging, fertilize the area, so more plants will grow. The energy contained in fertilizer is often used by fungus

Four things to remember in any nutrient cycle -

RASO Reservoirs A fast phase and a slow phase Soluble and insoluble forms Over geological time, biological concentrations increases

Orbital variations:

Slight variations in Earth's orbit lead to changes in the seasonal distribution of sunlight reaching the Earth's surface and how it is distributed across the globe. Milankovitch cycle influences temperature with ~41,000 and ~100,000 year periodicities. It is largely caused by variations in Earth's eccentricity (that Earth's orbit is not a perfect circle but an ellipse) and variations in the tilt angle of Earth's axis of rotation.

Chlorofluorocarbons (CFCs)

Synthetic compounds of entirely of industrial origin used in a number of applications, but now largely regulated in production and release to the atmosphere.

Reservoirs

The non-living forms of carbon, hydrogen, oxygen, nitrogen, and phosphorus form huge reservoirs in the physical environment. For instance, nitrogen makes up 78% of the atmosphere as N2, and hydrogen comes from water. A reservoir is a supply of a biologically meaningful element that is not easily obtainable by living organisms. Elements can have multiple reservoirs.

Over geological time the biological concentration to cycles increases.

This means the "bio" part of biogeochemical cycle will accumulate over time.

Volcanism

Volcanic eruptions affect global climate occur several times by partially blocking the transmission of solar radiation to the Earth's surface for a number of years. Volcanoes are also part of the extended carbon cycle, affecting carbon dioxide concentration at the atmosphere over geological time periods.

Climate change and overall economy

Warmer temperatures will also mean less snow overall at certain latitudes because more will fall as rain, and the snow that does fall will melt faster. This affects people living in areas that depend on snow-fed reservoirs for water. There are positive impacts also, for instance, because of global warming, as IPCC projects, it may increase 5-20% crop yields in the first decades of this century, but the crops will be more prone to failure if climate variability increases and precipitation becomes less dependable. And ironically, with higher temperatures comes an increased potential for killing freezes. This is because plants start growing earlier making them more vulnerable to sudden spring-time cold spells.

A fast phase and slow phase

When cycle occurs involving biological entities, it is faster. When geology is involved, the cycle is slower. The gaseous phase of the cycle is faster, the main sources of nutrients being atmosphere and ocean. Sedimentary phase of cycle is slower. Soil and rocks are the main source of nutrients in sedimentary phase of cycle. This phase of cycle is slow because weathering to release nutrients may take thousands to millions of years.

work

While doing work, energy is lost in entropy (as the second law of thermodynamics militates): In another word, energy runs downhill -- flowing from more concentrated to less concentrated form. Any living thing loses energy as heat constantly, and it has to be replenished constantly to live.

Carbon dioxide (CO2

a minor but very important component of the atmosphere, is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by a third since the Industrial Revolution began. increase of 280 ppm to 398 ppm

Climate change

average weather over a long period of time. Climate change is the aggregated altered patterns of weather. Weather patterns are dynamic, e.g., monthly variation. Earth's climate is also dynamic

The drivers of climate change

caused by variations in the Earth's orbit, differences in solar radiation (solar output), plate tectonics, volcanic eruptions, and increased emissions of green house gases (anthropogenic)

first law of thermodynamics

energy can neither be created nor destroyed but is transferred from one form to another

Difference between energy and nutrients

energy flows, nutrients cycle

nutrients can occur in ?

gaseous form (e.g., N2, CO2), mineral form (such as apatite -- the main P-containing mineral), inorganic ionic form (e.g., NH4 +, NO3 , H2PO4 ), and organic form bounded into various C-based compounds in living or dead organisms or their products. Plants take nutrients in the ionic form, animals in organic form (through consumption of living or dead tissues), and microorganisms in any mineral or organic form.

ultimate source of energy

solar rays from the sun