Ecosystems. Ecosystem : all organisms and non-living entities occurring and interacting in a particular area Animals, plants, water, soil, nutrients, etc . Community is a group of interacting living organisms sharing a populated environment. Energy flowing through an ecosystem.
Community is a group of interacting living organisms sharing a populated environment
Energy is released as heat in one-way flow through a system
Matter is conserved and cycles within a system
Primary production:conversion ofsolar energy to chemical energy by autotrophs
High net primary productivity: ecosystems whose plants rapidly convert solar energy to biomass
Which ecosystems have high net primary productivity and which have low net primary productivity?
NPP increases with temperature and precipitation on land, and with light and nutrients in aquatic ecosystems.
Phytoplankton blooms off the Louisiana coast.
Nitrogen comprises 78% of our atmosphere.
N2 + 8 H+ + 8 e− → 2 NH3 + H2
and in a form usable by organisms…..
Nitrifying bacteria convert ammonium ions first into nitrite ions then into nitrate ions
Denitrifying bacteriaconvert nitrates in soil or water to gaseous nitrogen, releasing it back into the atmosphere
Fully half of nitrogen entering the environment is of human origin.
Damming rivers increases evaporation and infiltration into aquifers.
Altering the surface and vegetation increases runoff and erosion.
Spreading water on agricultural fields depletes rivers, lakes, and streams and increases evaporation.
Overdrawing groundwater for drinking, irrigation, and industrial uses depletes groundwater resources.
Removing forests and vegetation reduces transpiration and lowers water tables.
Emitting pollutants changes the nature of precipitation.