“The early decades of the canning industry in the Pacific Northwest
can be described as nothing less than an all-out attack on salmon”.
Lichatowich 1999:111
“Fishery Failure” Declared for West Coast Salmon Fishery
Declaration Clears Path for Congressional Action
Secretary of Commerce Carlos M. Gutierrez today declared a commercial fishery failure for
the West Coast salmon fishery due to historically low salmon returns. Also today, NOAA’s
Fisheries Service issued regulations to close or severely limit recreational and commercial
salmon fishing in the area.
“The unprecedented collapse of the salmon population will hit fishermen, their families, and
fishing communities hard, and that is why we have moved quickly to declare a fishery disaster,”
Gutierrez said. “Our scientists are working to better understand the effects that ocean changes
have on salmon populations. We are also working closely with fishing communities to improve
salmon habitat in river systems to support sustainable fishing.”
Chapter
#5
Ecosystems and the Physical Environment
pg. 88 - 112
Readings last Week and this
Week:
Chapter #5 – “Free Wealth”
Facilitators: Labecca Hampton and Jessica Vidal
Chapter #6 – “Cultivate the Waters”
Facilitators: Patrick Grennan and Scott Arnold
Solar Radiation
o
Sun provides energy for life, powers biogeochemical
cycles, and determines climate
o
69% of incoming solar
radiation is absorbed by
atmosphere and earth
•
o
Remainder is reflected
Albedo
•
•
The reflectance of solar energy
off earth’s surface
Dark colors = low albedo
•
•
Forests and ocean
Light colors = high albedo
•
Ice caps
Temperature Changes with Latitude
o
Solar energy does not hit earth uniformly
•
Due to earth’s spherical shape and tilt
Equator (a)
High concentration
Little Reflection High
Temperature
Closer to Poles (c)
From (a) to (c)
In diagram below
Low concentration
Higher Reflection
Low Temperature
Temperature Changes with Season
Seasons
determined by
earth’s tilt (23.5°)
Causes each
hemisphere to tilt
toward the sun for
half the year
o
o
o
Northern Hemisphere tilts towards the sun from March
21- September 22 (warm season)
The Atmosphere
o
o
Invisible layer of gases that
envelopes earth
Content
•
•
•
o
o
21% Oxygen
78% Nitrogen
1% Argon, Carbon dioxide, Neon
and Helium
Density decreases with distance
from earth
Shields earth from high energy
radiation
Atmospheric Layers
Atmospheric Layers
o
Troposphere (0-10km)
•
•
Where weather occurs
Temperature decreases with altitude
Atmospheric Layers
o
Stratosphere (10-45km)
•
•
Temperature increases with altitudevery stable
Ozone layer absorbs UV
Atmospheric Layers
o
Mesosphere (45-80km)
•
Temperature decreases with altitude
Atmospheric Layers
o
Thermosphere (80-500km)
•
•
Gases in thin air absorb x-rays and
short-wave UV radiation = very hot
Source of aurora
Atmospheric Layers
o
Exosphere (500km and up)
•
•
Outermost layer
Atmosphere continues to thin until
converges with interplanetary space
Atmospheric Circulation
o
Near Equator
•
•
•
o
Warm air rises, cools and splits
to flow towards the poles
~30°N&S sinks back to surface
Air moves along surface back
towards equator
This occurs at higher latitudes
as well
•
Moves heat from equator to the
poles
Surface Winds
o
Large winds due in part
to pressures caused by
global circulation of air
•
o
High
Low
High
Left side of diagram
Winds blow from high
to low pressure
•
Low
High
Right side of diagram
Low
High
Coriolis Effect
o
Earth’s rotation influences direction of wind
•
•
o
Earth rotates from East to West
Deflects wind from straight-line path
Coriolis Effect
•
•
•
Influence of the earth’s rotation on movement of air and
fluids
Turns them Right in the Northern Hemisphere
Turns them Left in the Southern Hemisphere
Coriolis Effect
o
Visualize it as a Merry-Go-Round (see below)
Global Ocean Circulation
o
o
Prevailing winds produce ocean currents and
generate gyres
Example: the North Atlantic Ocean
•
•
•
o
Trade winds blow west
Westerlies blow east
Creates a clockwise gyre in the North Atlantic
Circular pattern influenced by coriolis effect
Position of Landmasses
Large landmasses in the
Northern Hemisphere
help to dictate ocean
currents and flow
Very little land in the
Southern Hemisphere
Vertical Mixing of Ocean
Ocean Interaction with
Atmosphere- ENSO
o
El Niño-Southern Oscillation (ENSO)
•
o
o
o
Definition: periodic large scale warming of surface waters of tropical
eastern Pacific Ocean
Alters ocean and atmospheric circulation patterns
Normal conditions- westward blowing tradewinds keep
warmest water in western Pacific
ENSO conditions- trade winds weaken and warm water
expands eastward to South America
•
Big effect on fishing industry off South America
Ocean Interaction with
Atmosphere- ENSO
ENSO Climate Patterns
Weather and Climate
o
Weather
•
•
o
The conditions in the atmosphere at a given place and
time
Temperature, precipitation, cloudiness, etc.
Climate
•
•
•
The average weather conditions that occur in a place
over a period of years
2 most important factors: temperature and precipitation
Earth as many climates
World Climates
Rain Shadows
o
o
o
Mountains force humid air to rise
Air cools with altitude, clouds form and
precipitation occurs (windward side)
Dry air mass moves down opposite leeward side of
mountain
Tornadoes
o
o
Powerful funnel of air associated with a severe
thunderstorm
Formation
•
•
•
o
o
Mass of cool dry air collides with warm humid air
Produces a strong updraft of spinning air under a cloud
Spinning funnel becomes tornado when it descends from
cloud
Wind velocity= up to 300mph
Width ranges from 1m to 3.2km
Tropical Cyclone
o
o
o
Giant rotating tropical storms
Wind >119km per hour
Formation
•
•
•
o
Strong winds pick up moisture over warm surface waters
Starts to spin due to Earth’s
rotation
Spin causes upward spiral
of clouds
Damaging on land
•
•
High winds
Storm surges
Biogeochemical Cycles
o
Matter (elements) moves between
ecosystems, biotic & abiotic
environments, and organisms
•
o
Biogeochemical cycling involves:
•
o
Unlike energy
Biological, geologic and chemical
interactions
Five major cycles:
•
Carbon, Nitrogen, Phosphorus,
Sulfur and Water (hydrologic)
The Carbon Cycle
x 1015g
of
Carbon
The Nitrogen Cycle
Nitrate
NO3
Nitrite
NO2-
Ammonia
NH3
Ammonium
NH4+
x 1012g of
Nitrogen
The Phosphorus Cycle
x 1012g of
Phosphorus
The Sulfur Cycle
x 1012g
of
Sulfur
The Water (Hydrologic) Cycle
km3 year
Internal Planetary Processes
o
Layers of the earth
•
Lithosphere
•
•
Asthenosphere
•
o
o
Outermost rigid rock layer composed of plates
Lower mantle comprised of hot soft rock
Plate Tectonics- study of the processes by which
the lithospheric plates move over the asthenosphere
Plate Boundary- where 2 plates meet
•
Common site of earthquakes and volcanoes
Plates and Plate Boundaries
Types of Plate Boundaries
o
Divergent Plate Boundary-2
plates move apart
o
Convergent Plate Boundary-2
plates move together (may get
subduction)
Types of Plate Boundaries
o
Transform Plate
Boundary- 2 plates
move horizontally
in opposite, parallel
directions
Earthquakes
o
Caused by the release of accumulated energy as
rocks in the lithosphere suddenly shift or break
•
•
o
o
o
Occur along faults
Energy released as seismic wave
Focus- the site where the earthquake originates
below the surface
Epicenter- located on the earth’s surface, directly
above the focus
Richter scale and the moment magnitude scales are
used to measure the magnitude
Tsunami
o
o
o
Giant undersea wave caused by an
earthquake, volcanic eruption or
landslide
•
Travel > 450mph
Tsunami wave may be 1m deep in
ocean
•
Becomes 30.5m high on shore
Magnitude 9.3 earthquake in Indian
Ocean
•
Triggered tsunami that killed over
230,000 people in South Asia and
Africa
Human Impacts of Nutrient Cycles
o
o
Hubbard Brook Watershed Study
Long term ecological research
Logging
Human Impact
Impact of Salmon on Ecosystems
Summary
o
o
o
o
o
o
Biogeochemical cycles in which elements are moved
Biogeochemical cycles are composed of reservoirs and
pathways. Fluxes between compartments can be measured.
Some elements cycle quickly such as those with a gaseous
phase.
Some cycles are internal with an ecosystem
Ecosystems can lose nutrients and be deposited elsewhere.
Humans can have an impact on nutrient cycling.