Water, Carbon, Nitrogen, & Phosphorus Cycles · Nitrogen Cycle Summary Air = 78% Nitrogen, can’t...
Transcript of Water, Carbon, Nitrogen, & Phosphorus Cycles · Nitrogen Cycle Summary Air = 78% Nitrogen, can’t...
Precipitation: snow, rain, sleet, hail
Evaporation: liquid to gas (from lakes and oceans to form clouds)
Condensation: gas to liquid (water vapor in clouds increases to form rain…)
Water Vapor
Most comes from oceans; a major greenhouse gas.
Also comes from trees and plants from transpiration.
Transpiration
Loss of water vapor from the leaves of plants.
Water vapor increases to also form clouds and eventually rain.
Respiration
NOT respiration as in breathing.
Cellular level - when organisms break down food, water is a by-product which is released.
Decomposition
Recycles carbon
Decomposers (microorganisms) break down organic matter (carbon) and returns it to the environment
Food
Food that we eat is broken down and the carbon is stored or used to build tissues.
Also is used for energy or released as methane.
Combustion
Important part of the cycle.
When wood or fossil fuels are burned, carbon dioxide is released.
Weathering
Rocks that contain carbon include “carbonates” such as limestone.
Weathering of limestone releases carbon.
Photosynthesis: CO2 sugar (C6H12O6)
Respiration: sugar (C6H12O6) CO2
Decomposition: carbon compounds returned to environment
Digestion: from food – stored in tissues or released
Combustion: burning wood or fossil fuels CO2
Weathering: breaking down some rocks like limestone releases
carbon
Air
About 78% of the air we breath is nitrogen but we can’t directly use this.
Nitrogen gas has to be “fixed” first.
Nitrogen Fixation
Combining nitrogen in the air with other elements to form useful compounds.
Some microorganisms can do this; also can be done by lightning.
Nitrogen Fixation
Can occur in some bacteria in soil.
Mostly occur in bacteria found in “nodules” on legumes (peanut, peas, alfalfa and bean plants).
Nitrogen Fixation
Nitrogen-fixing bacteria get food from the plants. Bacteria combine nitrogen gas with hydrogen to form ammonia and then nitrates that are used by the plants.
Nitrogen Fixation
When we eat plants we get a usable source of nitrogen which we can use.
Denitrification: release of nitrogen gas back into the atmosphere by breakdown of nitrogen compounds and ammonia by other bacteria.
Lightning
Plays a minor role in the nitrogen cycle.
Intense heat of lightning causes nitrogen to combine with oxygen to form nitrogen oxides. Falls to Earth in rain and is absorbed by plants.
Nitrogen Cycle Summary
Air = 78% Nitrogen, can’t use it
Nitrogen Fixation – microorganisms make unusable nitrogen into compounds we can use
Animals eat plants to get nitrogen
Decomposers: break down dead organisms, return nitrogen to soil
Is confined only to a local ecosystem.
Is not recycled globally.
Important in body components such as DNA and in energy molecules (ATP).
A MAJOR
energy
molecule