Nutrient Cycling

Biogeochemistry

Study of the physical, chemical, and biological factors that influence movement and transformation of elements

The ultimate source of mineral nutrients is _____________

Earth’s crust

nutrients

chemical elements required for metabolism and growth

______ determine the supply of nutrients.

Rates of physical and chemical transformations

Nutrients enter ecosystems through the

chemical breakdown of minerals in rocks or through fixation of atmospheric gases

_____ is the main component of plant structural compounds; ______ is largely tied up in enzymes

Carbon nitrogen

Some C4 and CAM plants require ______ . All animals require it.

Sodium

Some plants that host N-fixing bacteria require

Cobalt

Plants and microorganisms take up nutrients in simple, ____ forms from the environment.

Soluble

Animals mostly get nutrients in _____ as large, complex molecules. Some molecules are broken down; others are absorbed intact, such as some amino acids.

Good

All nutrients are ultimately derived from _______ ____________: minerals in rocks and gases in the atmosphere.

abiotic sources

Mechanical weathering

Physical breakdown of rocks

When tropical forests are cleared and burned, the nutrients are lost in

smoke and ash and soil erosion

Carbon is taken up as _____ by autotrophs through photosynthesis and fixed into organic compounds

CO2

Nitrogen fixation

The process of converting N2 into a biologically useful form