Transcript Ecosystems: What Are They and How Do They Work?

Ecosystems: What Are They
and How Do They Work?
Chapter 3
Sections 5-7
Soils
• Origins of soils
• Soil horizons: O, A, B, and C
• Soil profiles
• Infiltration and leaching
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
Red earth
Springtail
mite
Actinomycetes
Fungus
Fig. 3-21, p. 51
Soil Profiles
from Different
Ecosystems
Fig. 3-22, p. 52
Soil Profiles from Different Ecosystems
Mosaic
of closely
packed
pebbles,
boulders
Alkaline,
dark,
and rich
in humus
Weak humusmineral mixture
Dry, brown to
reddish-brown, with
variable accumulations
of clay, calcium
carbonate, and
soluble salts
Desert Soil
(hot, dry climate)
Clay,
calcium
compounds
Grassland Soil
(semiarid climate)
Fig. 3-22a, p. 52
Soil Profiles from Different
Ecosystems
Forest litter
leaf mold
Acidic
lightcolored
humus
Humus-mineral
mixture
Light-colored
and acidic
Light, grayishbrown, silt loam
Iron and
aluminum
compounds
mixed with
clay
Tropical Rain Forest Soil
(humid, tropical climate)
Acid litter
and humus
Humus and
iron and
aluminum
compounds
Dark brown
Firm clay
Deciduous Forest Soil
(humid, mild climate)
Coniferous Forest Soil
(humid, cold climate)
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
pH Scale
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
Precipitatio
n
to ocean
Surface
runoff
(rapid)
Infiltration and
percolation
Groundwater movement (slow)
Ocean storage
Fig. 3-24, p. 54
Human Intervention in the
Hydrologic Cycle
• Large withdraw of surface and
ground waters
• Clearing vegetation
• Pollution
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
Human Interference in the Global
Carbon Cycle
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
Human Interference in the Global
Nitrogen Cycle
Nitrogen fixation by natural processes
Nitrogen
Fig. 3-28, p. 58
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
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