TYPES OF ECO CYCLES

BIO-GEOCHEMICAL CYCLES:

INTRODUCTION

Organisms are built up on chemical substances.

These chemicals enter the organisms from the environment and come out after undergoing changes or without changes.

        The cyclic path of nutrients from the abiotic system to the biotic system  and back is called biogeochemical cycles also called nutrient cycles. cycle

PHASES OF BIOGEOCHEMICAL CYCLES

BIOTIC – Flow of nutrients in the living organisms through food chain

ABIOTIC – Flow of nutrients in the non-living environment.

TYPES OF BIOGEOCHEMICAL CYCLES

GASEOUS CYCLES   

        Main reservoirs are atmosphere and oceans.E.G. Carbon,nitrogen,oxygen cycle.

SEDIMENTARY CYCLES          

        Main reservoirs are soil and rocks. E.G. Sulphur cycle, phosphorous cycle etc..

CARBON CYCLE

It is the cyclic path of carbon

Flow of carbon into the Biotic system

Photosynthesis

Formation of shell

CO₂ + H ₂O                             H ₂CO₃

H ₂CO₃                                        H⁺ + HCO₃

HCO₃ +Ca⁺                             H⁺ + CaCO₃

Flow of carbon into the Abiotic system

Respiration

Decomposition

Shells

Coal deposition

NITROGEN CYCLE

Cyclic path of nitrogen, it is a gaseous cycle.

Flow of nitrogen into the biotic system

Electrochemical fixation   - nitrogen fixed by lightening

Biological fixation       - this is done by certain organisms called nitrogen fixers(Rhizobium,Nitrosomonas,Nitrococcus,Anabena…)

Flow of Nitrogen into the Abiotic system

Decomposition

Excretion