Answers

Ashwani
Jul 26, 2020

Standing state of soil The amount of nutrients, such as carbon, nitrogen, phosphorus, calcium, etc.,the present in the soil at any given time, is referred to as standing state of soil. It varies in different kind of ecosystem and also on a seasonal basis.

Nutrient cycling The movement of nutrients through various components of an ecosystem is called nutrient cycling or biogeochemical cycles. These are of two types,  i.e. gaseous and sedimentary. The cyclic account of carbon movement in nature.

Carbon cycle is the most common nutrient or biogeochemical cycle of an ecosystem.

  1. Carbon constitutes 49% of dry weight of an organism.
  2. About 71 % of carbon is found dissolved in oceans, which is responsible for its regulation in atmosphere.
  3. Carbon cycle occurs through atmosphere, ocean and through living and dead organisms.
  4. According to an estimate, 4 x 1013 kg of carbon is fixed in the biosphere through photosynthesis annually.
  5. Carbon is returned to atmosphere as C02 released by the animals and plants during respiration and by the activities of decomposers.
  6. Some amount of fixed carbon is lost to sediments and removed from circulation.
  7. The additional sources of carbon for the release in atmosphere are burning of wood, forest fire and combustion of organic matter, fossil fuel, volcanic activity.
  8. Human activities like deforestation, massive burning of fossil fuel for energy and transport have increased the rate of release of carbon dioxide into the atmosphere.