Transcript Chapter 5 power point

Chapter 5
Ecosystems
and the
Physical
Environment
Chapter 5
Ecosystems and the physical
Environment
Cycling of Materials within Ecosystems
Basics of biogeochemical cycling
Cycling of Materials within Ecosystems
Carbon cycle:
Nature is constantly taking carbon out of the atmosphere. These processes are
sometimes called carbon sinks.
Photosynthesis - Plants use photosynthesis to make energy and grow. They take
carbon dioxide (CO2), sunlight, and water and turn it into oxygen and sugar. Large
areas of plants like the rainforest help to remove lots of carbon from the
atmosphere.
The ocean - Ocean water does a lot to remove excess carbon from the
atmosphere. Carbon dioxide in the air reacts with the sea water to make carbonic
acid in the ocean. If there is too much carbonic acid, you may get acid rain, which
is not good. However, some carbonic acid is good as it is used by sea organisms
to make their shells. These shells will eventually become sedimentary rock like
limestone.
diazotrophs
For Nitrogen to be used by different life forms on Earth, it must change into different states. Nitrogen in the atmosphere,
or air, is N2. Other important states of nitrogen include Nitrates (N03), Nitrites (NO2), and Ammonium (NH4).
Processes in the Nitrogen Cycle
Fixation - Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into
ammonium.
Nitrification - This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants
can then absorb.
Assimilation - This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets
used in amino acids, nucleic acids, and chlorophyll.
Ammonification - This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria
turn the nitrogen back into ammonium so it can reenter the nitrogen cycle.
Denitrification - Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task
as well.
Why is nitrogen important to life?
Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino
acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to
make their food and energy.
How have humans altered the nitrogen cycle?
Unfortunately, human activity has altered the cycle. We do this by adding nitrogen into the soil with fertilizer as well as
other activities that put more nitrous oxide gas into the atmosphere. This adds in more nitrogen than is needed by
normal cycle and upsets the cycle's balance.
Facts
Around 78% of the atmosphere is nitrogen.
Nitrogen is used in fertilizer to help plants grow faster.
Nitrous oxide is a greenhouse gas. Too much of it can also cause acid rain.
Nitrogen has no color, odor, or taste.
It is used in many explosives.
About 3% of your body weight is nitrogen.
Cycling of Materials within Ecosystems
Nitrogen cycle:
Atmospheric
nitrogen (N2)
Biological
nitrogen
fixation
Nitrogen
fixation by
humans
Decomposition
Denitrification
NH3 &
NH4-
Internal
cycling
Plant & animal
proteins
Assimilation
Nitrification
NO3-
Cycling of Materials within Ecosystems
Phosphorus cycle:
Phosphate rocks
Excretion /
decomposition
Phosphate
mining
Erosion
Internal
cycling
Marine
organisms
Marine
sediments
Fertilizer
containing
phosphates
Animals, crops
Dissolved
phosphates
Erosion
Internal
cycling
Soil phosphates
Cycling of Materials within Ecosystems
Sulfur cycle:
Cycling of Materials within Ecosystems
Hydrologic cycle:
Solar Radiation
Solar Radiation
Temperature Changes with Latitude
Like equator
Like at poles
Solar Radiation
Temperature Changes with Season
The Atmosphere
Composition
Nitrogen
Oxygen
Carbon dioxide
Argon
Water vapor
Pollutants
Helium
Etc.
78%
21%
1%
The Atmosphere
Layers of the
Atmosphere
The Atmosphere
Atmospheric Circulation
Circulation
spawned
by heating
/ cooling
Prevailing
winds
Generated by
pressure
differences
and Coriolis
effect
The Atmosphere
The Coriolis Effect
The Global Ocean
Patterns of Circulation in the Ocean
The Global Ocean
Patterns of Circulation in the Ocean
Influenced by:
1) Coriolis Effect
2) Land Masses
The Global Ocean
Vertical Mixing of Ocean Water
The Global Ocean
Ocean Interactions with the Atmosphere
The Global Ocean
Ocean Interactions with the Atmosphere
Upwelling
This decreases
during El Niño
Increases
during La Niña
El Niño significantly wetter winters are
present in northwest Mexico and the
southwest United States including central
and southern California, while both cooler
and wetter than average winters in
northeast Mexico and the southeast United
States
La Niña often causes drought conditions in
the western Pacific; flooding in northern
South America; mild wet summers in
northern North America, and drought in the
southeastern United States.
Weather and Climate
Examine the definitions for climate and
weather. What is wrong with the following
statement?
“Global warming cannot be occurring, we
had a very cool summer.”
Weather and Climate
Rain shadows
Insert Fig 5.19 b
Weather and Climate
Severe weather events:
1) Tornados
Frequency of tornados annually per 100,000 km2
Tornado Alley (US)
40
Sydney, Australia
8
United Kingdom
1
Bangledesh
0.6
Source: University of Wyoming, Department of Atmospheric Science
Weather and Climate
Severe weather events:
2) Tropical cyclones
Atlantic Ocean = hurricanes
Pacific Ocean = typhoons
Indian Ocean = cyclones
Weather and Climate
But, all are the same severe weather event:
The Earth’s crust and how it
moves
Do now:
1. What is the Coriolis Effect?
2. Which side of a mountain range will you
find a desert?
3. What affects ocean currents?
4. Remember Tuesday test chapter5.
Internal Planetary Processes
Plate tectonics
Internal Planetary Processes
Plate boundaries
Internal Planetary Processes
Plate boundaries
Internal Planetary Processes
Volcanoes
Most volcanoes occur
along subduction zones
Internal Planetary Processes
Volcanoes
Some occur along
spreading zones
Few, such as Hawaiian
Islands, not associated
with plates.
Internal Planetary Processes
Earthquakes
• caused by release of built up stress,
typically along faults
• movement releases seismic waves
Typical side effects include:
1) Landslides
2) Tsunamis