Transcript APES Chapter 6

Biogeography: Climate, Biomes,
and Terrestrial Biodiversity
WEATHER

Short term tropospheric
properties such as:
• Temperature
CLIMATE


• Pressure
• Cloud cover
• Humidity
• Precipitation
• Wind direction and speed

The average long-term
weather of an area.
Averaged over at least 30
years.
Determined by two main
factors: average
temperature and average
precipitation.
 Masses
of air are constantly moving
 Weather front—the boundary between
two different air masses.
 Warm front—warm air mass moves up
and over of cold air mass.
 Cold front—cold air mass wedges
beneath a warm air mass.
 The
most dramatic changes in weather
occur along a front.
 Tornadoes—form
over land when cool
downdrafts and warm updrafts meet
during a thunderstorm.
 Tornado season in the United States is
usually March through August.
 Tropical
cyclones—form over warm
ocean waters.
• Hurricanes—in the Atlantic
• Typhoons—in the Pacific
NEGATIVE EFFECTS:

Kill and injure people,
property, and agriculture
production.
POSITIVE EFFECTS:


Flush excess nutrients from
land runoff
Carve channels through
barrier islands allowing
huge quantities of fresh
seawater to flood bays and
marshes which can
increase production of
commercially important
species of shellfish and
fish.
1.
2.
Uneven heating of the Earth’s surface
Seasonal changes occur because the
Earth’s axis is tilted.
Fig. 6-8 p. 116
3.
The Earth rotates on its axis.
*Causes the Coriolos Effect
4.
Long term variations in the amount of
solar energy striking the Earth.
*Milankovitch Cycles--Earth’s wobble (22,000
yrs.), tilt (44,000 yrs.) and changes in the
shape of the Earth’s orbit (100,000 year cycle)
 Redistribute
heat received form the sun
and influence climate and vegetation
especially near coastal areas.
 For
example:
• The Gulf Stream brings warm water up from the
tropics.
• Upwellings
• El Nino-Southern Oscillation
• La Nina
 Wind
blowing along steep western
coasts of continents push surface water
away from land.
 This water is replaced by cold, nutrientrich bottom waters called upwellings.
 Nutrients from upwellings support large
populations of phytoplankton,
zoophankton, fish and fish-eating birds.
 During
an El Nino, the prevailing westerly
winds weaken or cease.
 This causes upwellings to cease.
• Surface water along North and South America
becomes warmer.
• Nutrients are not brought to the surface causing
a sharp decline in the numbers of some fish
species.
• Can trigger extreme weather changes over most
of the globe, especially the Pacific and Indian
Oceans.
Fig. 6-14 p. 119
 Sometimes
El Nino is followed by La
Nina.
 Westerly winds are stronger than normal
resulting in more upwellings.
 Also results in extreme weather changes
over most of the globe.
• Colder waters in the pacific
• More Atlantic hurricanes
El Niño and La Niña.mht
 Gasses
in the atmosphere, known as
greenhouse gasses, trap long wavelength
radiation (infrared) from the sun warming
the air.
 Greenhouse
Gasses:
• Water vapor
• Carbon dioxide
• Methane
 Without
the natural greenhouse effect,
the Earth would be a cold, mostly lifeless
planet.
 Various
topographic features create local
climatic conditions, or microclimates, that
differ from the general climate of a
region. Examples:
• Mountains: Rain shadow Effect
• Vegetation: take up and release water
• Cities: bricks, concrete absorb heat
 Terrestrial
regions of the Earth
characterized by communities of
organisms adapted to the climate.
 Annual
precipitation, temperature, and
soil are the most important abiotic
factors that influence the location of
biomes.
Aquatic Ecology: Biodiversity in
Aquatic Systems
MARINE (SALTWATER)






Estuaries
Coastlines
Coral reefs
Coastal marshes
Mangrove swamps
Oceans
FRESHWATER


Lakes and ponds
Streams and rivers
 Phytoplankton–
plant plankton—
microscopic photosynthesis organisms.
 Zooplankton—animal plankton–
nonphotosynthetic primary and
secondary consumers range from singlecelled to large invertebrates.
 Nekton—strong swimming consumers
such as fish, turtle, and whales.
 Benthos—bottom dwellers
 Decomposers—mostly bacteria
 Less
pronounced and fixed physical
boundaries than terrestrial ecosystems.
 More complex and longer food chains and
food webs
 More
difficult to monitor due to their size
and because they are largely hidden from
view.
 In
addition to salinity levels, the most
important abiotic factors in aquatic life
zone are:
 1. Sunlight for photosynthesis.
Photosynthesis is confined mostly to the
upper laver, or euphotic zone.
 2.
Temperature
 3.
Dissolved oxygen (DO)—most fist die
when the dissolved oxygen levels fall
below 5 ppm.
• Factors influencing DO levels include:
 Temperature
 Number of producers (add oxygen)
 Number of consumers and aerobic decomposers
(remove O2)
 4.
Availability of nutrients
 Estuaries—An
ecotone between the
marine environment and the land where
large volumes of fresh water from land
and salty ocean water mix.
 Intertidal
Zone—the area between high
tide and low tide; changing moisture and
salinity levels, numerous ecological
niches.
 Coral
reefs—form in clear, warm coastal
waters of the tropics and subtropics.
• Among the world’s oldest, most diverse, and
productive ecosystems.
• Home for about one-fourth of all marine species.
• Often called the (Rainforest of the Sea)
• Vulnerable to damage because they:
 Grow slowly
 Are disrupted easily
 Corals can live only in water temps. of 18-30 deg. C.
(64-86 F)
Standing water—lakes and ponds
Flowing water—streams and rivers
 Classified
according their nutrient levels.
 Oligotrophic—young, deep
lake with low
nutrient levels and limited food.
 Eutrophic—old, more shallow lake with
high nutrient levels and complex feeding
relationships.
 Mesotrophic –fall between the two
extremes.
Fig. 7-21 p. 158
Fig. 7-21 p. 158
 Cultural
eutrophication—occurs when
human activities speed the
eutrophication processes.
 Nutrients
in runoff are carried into a lake
causing a rapid increase in algae growth
that then die and decay.
 Aerobic bacteria causing the decay of
the plants, remove large amounts of
oxygen causing the death of many other
species.