Transcript You Light Up My Life

Ecosystems: What Are
They and How Do They
Work?
Chapter 3
Sections 5-7
Importance of Soils

Provides nutrients for plant growth (Base of
life on land)

Water Cleansing & Storage

Helps decompose & recycle waste

Potentially renewable resource
(1 cm of soil requires 15yrs to several hundred years to form)

Climate Control - CO2 storage
Soil Horizons

O Horizon = surface litter - Brown or Black Nondecomposed leaves, twigs, crop & animal waste, fungi ,

A Horizon = Topsoil - Dark & Loose
porous mixture of partially decomposed humus, and inorganic minerals

B Horizon = subsoil

C Horizon = Parent Material
Soil Formation and Horizons
Oak tree
Wood
sorrel
Lords and
ladies
Dog violet
Earthworm
Fern
Millipede
Honey
fungus
Mole
Grasses and Organic debris
small shrubs builds up
Moss and Rock
fragments
lichen
O horizon
Leaf litter
A horizon
Topsoil
Bedrock
B horizon
Subsoil
Immature soil
Regolith
Young soil
Pseudoscorpion
Mite
C horizon
Parent
material
Nematode
Root system
Mature soil
Red earth
Springtail
Fungus
mite
Bacteria
Actinomycetes
Fig. 3-21, p. 51
Soil Profiles
from Different
Ecosystems
Gray,
Gray, yellow & red
topsoils are low in
organic matter &
need N to support
crops
Fig. 3-22, p. 52
Animation
Soil profiles interaction
pH

Acidity or alkalinity of water or water-bearing samples

Scale 0-14

Acidic: pH 0-6.9

Neutral pH 7.0

Alkaline (basic): pH 7.1-14
The pH Scale
Fig. 3-23, p. 192
Matter Cycling in Ecosystems:
Biogeochemical Cycles

Nutrient (biogeochemical) cycles

Hydrologic (water) cycle

Carbon cycle

Nitrogen cycle

Phosphorus cycle

Sulfur cycle
Simplified Hydrologic (Water) Cycle
Condensation
Rain clouds
Transpiration
Precipitation
Precipitation
to land
Transpiration
from plants
Rapid
Surface runoff
(rapid)
Evaporation
Evaporation
From
ocean
Precipitation
Evaporation
From
ocean
Precipitation
to ocean
Surface
runoff
(rapid)
Infiltration and
percolation
Groundwater movement (slow)
Ocean storage
Fig. 3-24, p. 54
Animation
Water cycle interaction
Human Interventions in the
Hydrologic Cycle
1.
Large withdraw of surface and ground waters
2.
Clearing vegetation / wetland destruction -  runoff,
3.
Pollution - addition of nutrients
 infiltration,  groundwater recharge,  flood risk,  soil
erosion & landslides
The Carbon Cycle (Marine)
Diffusion between
atmosphere and ocean
Carbon dioxide
dissolved in
ocean water
photosynthesis
Combustion of fossil fuels
aerobic
respiration
Marine food webs
Producers, consumers,
decomposers, detritivores
incorporation
death,
into sediments sedimentation
uplifting over
geologic time
sedimentation
Marine sediments, including
formations with fossil fuels
Fig. 3-25a, p. 56
The Carbon Cycle (Terrestrial)
Atmosphere
(most carbon is in carbon dioxide)
Combustion
of fossil
fuels
volcanic action
Terrestrial
rocks
weathering
photosynthesis
aerobic
respiration
Land food webs
Producers, consumers,
decomposers,
detritivores
combustion of
wood (for clearing
land; or fuel)
deforestaion
Soil water
(dissolved carbon)
death, burial, compaction over geologic time
Peat,
fossil fuels
leaching,
runoff
Fig. 3-25b, p. 57
Animation
Carbon cycle animation- LEARN THE CARBON CYCLE!
Human Interferences in the
Global Carbon Cycle
1. Clearing Vegetation
2. Burning Fossil Fuels
potential consequences?
High
projection
Low
projection
Fig. 3-26, p. 56
The Nitrogen Cycle
Gaseous Nitrogen (N2)
in Atmosphere
Nitrogen
Fixation
by industry
for agriculture
Food Webs
on Land
Fertilizers
uptake by
autotroph
s
excretion, death,
decomposition
uptake by
autotroph
s
Nitrogen Fixation
bacteria convert N2 to
ammonia (NH3); this
dissolves to form
ammonium (NH4+)
NH3, NH4+
in Soil
loss by
leaching
Nitrogenous Wastes,
Remains in Soil
Ammonification
NO3–
in Soil
by bacteria
2. Nitrification
bacteria, fungi convert the
residues to NH3; this
dissolves to form NH4+
bacteria convert NO2–
to nitrate (NO3–)
1. Nitrification
NO2–
in Soil
bacteria convert NH4+
to nitrite (NO2–)
Denitrification
loss by
leaching
Fig. 3-27, p. 58
Animation
Nitrogen cycle interaction - LEARN THE NITROGEN CYCLE!
(Animations on School Server)
Human Interferences in the
Global Nitrogen Cycle
1. Add nitric oxide (NO) to atmosphere - can
form acid rain
2. Add nitrous oxide N2O to atmosphere via
anaerobic decomposition & inorganic fertilizers
- greenhouse gas
3. Nitrate in inorganic fertilizers can leach thru
soil & contaminate groundwater
4. Release large quantities of N into troposphere
via habitat destruction
5. Upset aquatic ecosystems from excess nitrates
in ag. runoff & sewage- eutrophication
The Phosphorus Cycle
mining
Fertilizer
Guano
excretion
agriculture
uptake by
autotrophs
Marine
Food Webs
uptake by
autotrophs
Dissolved
in Ocean
Water
leaching, runoff
Dissolved
in Soil Water,
Lakes, Rivers
death,
decomposition
sedimentation
Land
Food
Webs
weathering
weathering
settling out
uplifting over
geologic time
Marine Sediments
Rocks
Fig. 3-29, p. 59
Animation
Phosphorus cycle animation
Human Interventions in the
Phosphorus Cycle
1. Mining of phosphate rock
2. Clearing tropical forests reduces available
phosphate in tropical soils
3. Phosphates from runoff of animal wastes, sewage
& fertilizers disrupts aquatic ecosystems
- eutrophication
“Since 1900, human activities have increased the
natural rate of phosphorous release to
environment by about 3.7 fold”
The Sulfur Cycle
Water
Sulfur trioxide
Ammonia
Ammonium sulfate
Oxygen
Sulfur dioxide
Acidic fog and precipitation
Sulfuric acid
Hydrogen sulfide
Plants
Volcano
Dimethyl sulfide
Animals
Industries
Ocean
Sulfate salts
Metallic
Sulfide
deposits
Decaying matter
Sulfur
Hydrogen sulfide
Fig. 3-30, p. 60
Animation
Sulfur cycle animation
How Do Ecologists Learn
about Ecosystems?

Field research

Remote sensing

Geographic information system (GIS)

Laboratory research

Systems analysis
Geographic Information System (GIS)
Critical nesting site locations
Private
owner 1
USDA
Forest Service
USDA Forest Service
Private owner 2
Topography
Forest
Wetland
Habitat type
Lake
Grassland
Real world
Fig. 3-31, p. 61