What is Carbon Cycle ? Human Impact Explained

The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere , lithosphere, hydrosphere and atmosphere of the earth. Carbon is the basic constituent of all organic compounds and is the major elements forming around 49% of the weight of the organisms . the atmosphere also consist around 0.032% carbon. carbon is fixed in the form of plants through photosynthesis. During photosynthesis carbon dioxide present in the air (atmosphere) and dissolved in the water is used . A large amount of carbon dioxide is also found dissolved in oceans Oceans comprise of 50% more carbon dioxide in comparison to atmosphere. 

  • Save
Car­bon Cycle

The major source of car­bon in all liv­ing beings , dead organ­ic mat­ter and fos­sils deposits is in the form of car­bon diox­ide . in the envi­ron­men­tal phase, car­bon diox­ide resides in the reser­voir or sinks such as atmos­phere or the sur­face water. The sur­face water is present in lakes rivers and oceans . The four main reser­voir of car­bon name­ly atmos­phere, ter­res­tri­al bios­phere (usu­al­ly includes fresh­wa­ter sys­tem) ‚oceans and sed­i­ments (includes fos­sils rules) are inter­con­nect­ed with each oth­er . About 99% of the total car­bon is present on the earth­’s crust as deposit of coal, petro­le­um, peat and lime­stone . weath­er­ing of rocks , burn­ing of fos­sils fuels , vol­canic activ­i­ty returns the bound car­bon to the atmos­pher­ic aquat­ic reservoir.

The exchange of car­bon between to the atmos­phere aquat­ic reser­voir occurs because of var­i­ous chem­i­cal , phys­i­cal ‚geo­log­i­cal and bio­log­i­cal process­es . The oceans con­tains largest pool of car­bon near the suface of the earth . Accord­ing to esti­mate car­bon pool involved in glob­al car­bon cycle is around 55000 giga­tons. The oceans con­tain 38000 giga­tons of active car­bon pool as bicar­bon­ate and car­bon­ate ions.

The car­bon diox­ide (gaseous form of car­bon) from the atmos­pher­ic reser­voir is tak­en up by the pro­duc­ers and then trans­ferred to con­sumer to decom­pos­er and back to reser­voir. Atmos­pher­ic car­bon diox­ide is absorbed by plants and oth­er pho­to­syn­thet­ic organ­ism present in the ter­res­tri­al ecosys­tem. This way the car­bon diox­ide enters the organ­is­mic phase . About 4 — 9 × 10 13 kg of car­bon diox­ide is fixed through pho­to­syn­thet­ic activ­i­ty of plants each year . the liv­ing organ­isms con­vert car­bon diox­ide into organ­ic food mate­r­i­al which are passed to oth­er troph­ic lev­el of the food chain. Car­bon diox­ide enters the envi­ron­men­tal phase via cel­lu­lar ener­gy pro­duc­tion I.e. res­pi­ra­tion of the organ­ism in the graz­ing abd detri­tus food chains.

In aquat­ic envi­ron­ment dis­solved car­bon diox­ide car­bon diox­ide is utilised by phy­to­plank­ton. Car­bon present as bicar­bon­ate and car­bon­ates gets con­vert­ed into car­bon diox­ide that is used by phy­to­plank­ton . the car­bon diox­ide released dur­ing res­pi­ra­tion is also reuti­li­ized by the phy­to­plank­ton. The car­bon diox­ide released dur­ing res­pi­ra­tion is also reuti­lized by the phy­to­plank­ton to pro­duce more bio­mass . car­bon bound in the shells of snails , foraminifera as car­bon­ates is also deposit­ed in sed­i­ments after the death of ani­mals . A sig­nif­i­cant frac­tion of car­bon gets buried in the sed­i­ment and is removed from circulation.

The car­bon diox­ide present in atmos­phere exists in dynam­ic equi­lib­ri­um with that present in oceans . Atmos­pher­ic car­bon diox­ide gets eas­i­ly dis­solved in water or the aquat­ic phase through pre­cip­i­ta­tion . The dis­solved car­bon diox­ide forms car­bon­ic acid which dis­so­ci­ate to form hydro­gen and car­bon­ate ions. The Rate of reac­tion depends upon the con­cen­tra­tion of car­bon diox­ide . All these events shift the equi­lib­ri­um of the car­bon con­cen­tra­tion. Some amount of bio car­bon­ate ions are used by aquat­ic plants dur­ing pho­to­syn­the­sis. Oth­er mol­e­cules of car­bon monox­ide (CO) , methane (C6H12O6) and many oth­ers as well as many ions con­tain­ing carbon .

The glob­al car­bon bud­get is the bal­ance of the exchange (incomes and loss­es ) of car­bon between the reser­voir or one spe­cif­ic loop (eg. Atmos­phere bios­phere) of the car­bon cycle . an exam­i­na­tion of the car­bon bud­get of a pool or reser­voir can pro­vide infor­ma­tion about whether the pool or reser­voir is func­tion­ing as a source or sink for car­bon diox­ide. The dif­fer­ence between the car­bon uptake by plants dur­ing pho­to­syn­the­sis and released through res­pi­ra­tion gives the net pri­ma­ry pro­duc­tiv­i­ty. the rate of pri­ma­ry pro­duc­tiv­i­ty and decom­po­si­tion deter­mines the rate at which car­bon cycles through the ecosys­tem . In warm wet ecosys­tem such as trop­i­cal rain­forests, the pro­duc­tion and decom­po­si­tion rates are high , hence the car­bon is cycled quick­ly . in cool­er ecosys­tem the decom­po­si­tion is slow hence the dead organ­ic mat­ter accu­mu­lates . The pro­duc­tion and use of car­bon diox­ide varies depend­ing upon the tem­per­a­ture availability.

Human Impact on Car­bon cycle

Indus­tri­al rev­o­lu­tion and increas­ing human activ­i­ties such as large scale fos­sils fuel burn­ing have increased the con­cen­tra­tion of car­bon diox­ide in the envi­ron­ment. Before the indus­tri­al rev­o­lu­tion a bal­anced amount of car­bon diox­ide has increased sev­er­al hun­dred folds. 

  • Save
Burn­ing in Forest

Accord­ing to an esti­mate around 8 bil­lion tons of car­bon diox­ide is added to the atmos­phere each year and lev­els have increased by 35% in the last 130 years . The amount has increased main­ly due to com­bus­tion of fos­sils fuels and deforestation. 

As the lev­el of car­bon diox­ide increas­es , the glob­al tem­pra­ture also increase. This is because car­bon diox­ide traps the heat escap­ing from earth. The rise in tem­per­a­ture alters. The rain­fall pat­tern affect­ing the agri­cul­tur­al production.

The changes in food pro­duc­tion can affect the sur­vival of species present. In an area . Indi­rect­ly the rise in tem­per­a­ture can lead to melt­ing of glac­i­ers , rais­ing the sea lev­el by sev­er­al meters and hence threat­en­ing the sur­vival of organ­isms liv­ing in the coastal areas.

Leave a Comment

Share via
Copy link
Verified by MonsterInsights