The Cycling of Matter and Energy in the Environment
Living organisms consume nutrients and energy to thrive
- In particular, six “macronutrients” are constantly recycled – they are carbon, oxygen,
hydrogen, nitrogen, phosphorus, and sulfur.
- Biogeochemical cycles are physical and chemical processes which ensure the
exchange of matter and energy between the biotic and abiotic parts of the ecosphere
- To understand these cycles, we must understand the nature of matter and energy
Biogeochemical Cycles Part 1 Matter
Matter, Elements and Atoms: Matter: Anything that takes up space and has mass.
o Composed of atoms of elements which interact chemically with one another
to form more complicated molecules of compounds.
Elements: The basic chemical constituents of matter, ie. The stuff from which all
things are made
o Each element has distinct physical properties
o Elements cannot be further broken down by chemical means.
Atom: The basic physical unit of an element, ie. The smallest piece of matter that
exhibits the properties of that element;
o The physical characteristics of an atom determine the properties of the
- Atoms themselves are composed of tiny sub atomic particles
o Protons The basic constituents of all atoms
Structure of the atom: A small, dense nucleus of protons and neutrons,
surrounded by a large, diffuse cloud of electron.
Size: about 10^-10 m.
Each sub atomic particle carries a specific electric charge. The electromagnetic
force acts between charged particles, exerting a force which depends on the
Two positively charged (+,-) particles will attract one another Particles that are electrically neutral (carry no charge) do not experience this
Protons: + (positive charge)
Neutrons 0 (neutral charge)
Electrons: - (negative charge)
Identity of Atoms:
What gives an atom its particular chemical properties 9 and thus determines which
element it correspond