Ecosystems.pptx

Ecosystems: Components,

Energy Flow, and Matter

Cycling

Key Questions:

What is ecology?

What are the major parts of the earth’s life support systems?

What are the major components of an ecosystem?

What happens to matter and energy in ecosystems?

What are ecosystem services?

Ecology and the levels of

organization of matter

Ecology—Greek oikos meaning house

Study of how organisms interact with one another and their non-living environment (biotic and abiotic components)

Studies connections in nature on the thin life supporting membrane of air, water, and soil Levels of Organization of Matter

Ecosystem Organization

Organisms

Made of cells

Eukaryotic vs Prokaryotic

Species

Groups of organisms that resemble one another in appearance, behavior, and genetic make up

Sexual vs Asexual reproduction

Production of viable offspring in nature 1.5 million named; 10-14 million likely

Populations

Genetic diversity

Communities Ecosystems Biosphere

Fig. 4.2, p. 66 Biosphere

Biosphere

Ecosystems

Communities

Populations

Earth’s Life Support Systems

Troposphere

To 11 miles Air is here

Stratosphere

11 to 30 miles Ozone layer

Hydrosphere

Solid, liquid, and gaseous water

Lithosphere

Crust and upper mantle

Contains non-renewable res.

Atmosphere

Vegetation and animals Soil Rock Biosphere Crust core Mantle Lithosphere Crust Lithosphere

(crust, top of upper mantle)

Hydrosphere

(water)

Atmosphere

(air)

Biosphere

(Living and dead organisms)

Crust

Sustaining Life on Earth…

One way flow of high quality

energy

The cycling of matter (the

earth is a closed system)

Gravity

Causes

downward movement of matter

Biosphere

Carbon

cycle Phosphoruscycle Nitrogencycle Watercycle Oxygencycle

Heat in the environment

Major Ecosystem Components

Abiotic

Components

Limiting Factors on Land & in H

O

Terrestrial

Temperature Precipitation Soil nutrients Fire frequency Wind

Latitude Altitude

Aquatic/Marine

• Water clarity

Water currents

Dissolved nutrient concentrations

• Esp. N, P, Fe

Dissolved Oxygen concentration

The Source of High Quality Energy

Energy of sun lights and warms the planet Supports photosyn. Powers the cycling of matter Drives climate and weather that distribute heat and H₂O

Solar

radiation Energy in = Energy out

Reflected by atmosphere (34%) UV radiation Absorbed by ozone Absorbed by the earth

Visible light Lower Stratosphere (ozone layer) Troposphere Heat Greenhouse effect Radiated by atmosphere as heat (66%)

Earth

Fate of Solar Energy…

Earth gets 1/billionth of sun’s output of nrg 34% is reflected away by atmosphere

66% is absorbed by chemicals in atm = re-radiated into space

Visible light, Infrared radiation (heat), and a small amount of UV not absorbed by ozone reaches the atmosphere

Energy warms troposphere and land

Evaporates water and cycles it along with gravity Generates winds

A tiny fraction is captured by photosynthesizing organisms

Primary Productivity

The conversion of light energy to chemical

energy is called “gross primary production.” Plants use the energy captured in

photosynthesis for maintenance and growth.

Primary Productivity

NPP=GPP-respiration rate

GPP= RATE at which producers convert solar energy into chemical energy as biomass

Rate at which producers use photosynthesis to fix inorganic carbon into the organic carbon of their tissues

These producers must use some of the total biomass they produce for their own respiration

NPP= Rate at which energy for use by consumers is stored in new biomass (available to consumers)

Units Kcal/m2/yr or g/m2/yr

How do you measure it? AP Lab Site

What are the most productive

Ecosystems?

Estuaries Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Lakes and streams Continental shelf Open ocean Tundra (arctic and alpine) Desert scrub Extreme desert

800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600

Fate of Primary Productivity and

Some important questions…

Since producers are ultimate source of all food, why shouldn’t we just harvest the plants of the world’s marshes?

Why don’t we clear cut tropical rainforests to grow crops for humans?

Why not harvest primary producers of the world’s vast oceans?

Vitousek et al: Humans now use, waste, or destroy about 27% of earth’s total

Biotic Components of Ecosystems

Source of all food

Photosynthesis

Consumers=heterotroph Aerobic respiration

Anaerobic respiration

Methane, H₂S

Decomposers

Matter recyclers…

Trophic

Levels

Each organism in an ecosystem is assigned to a feeding (or Trophic) level

Primary Producers

Primary Consumers (herbivores) Secondary Consumer (carnivores) Tertiary Consumers

Omnivores

Detritus feeders and scavengers

Directly consume tiny fragments of dead stuff

Decomposers

Digest complex organic chemicals into inorganic nutrients that are used by producers

Detritivores vs Decomposers stop

Fig. 4.15, p. 75 Mushroo

m Wood

reduced to powder Long-horned

beetle holes

Bark beetle engraving

Carpenter ant galleries

Termite and carpenter

ant work

Dry rot fungus

Detritus feeders Decomposers

Energy Flow and Matter Cycling in Ecosystems…

Food Chains vs. Food Webs

KEY: There is little if no matter waste

in natural ecosystems!

Heat Heat Heat Heat

Heat

Heat

Heat First Trophic

Level

Second Trophic Level

Third Trophic Level

Fourth Trophic Level

Solar energy

Producers

(plants) consumersPrimary (herbivores) Tertiary consumers (top carnivores) Secondary consumers (carnivores) Detritvores

Generalized Food Web of the Antarctic

Fig. 4.18, p. 77

Humans

Blue whale Sperm whale

Crabeater seal

Killer

whale _Elephant seal Leopard

seal

Adélie

penguins Petrel

Fish

Squid

Carnivorous plankton

Krill

Phytoplankton

Herbivorous zooplankton

Emperor penguin

Note: Arrows

Go in direction Of energy

Food Webs and the Laws of matter and energy

Food chains/webs show how matter and energy move from one organism to another through an ecosystem

Each trophic level contains a certain amount of biomass (dry weight of all organic matter)

Chemical energy stored in biomass is transferred from one trophic level to the next

With each trophic transfer, some usable energy is degraded and lost to the environment as low quality heat

• Thus, only a small portion of what is eaten and digested is

actually converted into an organisms’ bodily material or biomass (WHAT LAW ACCOUNTS FOR THIS?)

Ecological Efficiency:

The % of usable nrg transferred as biomass from one trophic level to the next (ranges from 5-20% in most ecosystems, use 10% as a rule of thumb)

Pyramids of Energy and Matter

Pyramid of Energy Flow

Pyramid of Biomass

Heat Heat Heat Heat Heat 10 100 1,000 10,000 Usable energy Available at Each tropic level

Implications of Pyramids….

Why could the earth support more people if the eat at lower trophic levels?

Why are food chains and webs rarely more than four or five trophic levels?

Why do marine food webs have greater ecological efficiency and therefore more trophic levels than terrestrial ones?

Why are there so few top level carnivores? Why are these species usually the first to

Ecosystem Services and Sustainability

control Recycling_vital

chemicals _Renewable energy resources Nonrenewable energy resources Nonrenewable mineral resources Potentially renewable matter resources Biodiversity and gene pool Natural pest and disease control Waste removal and detoxification Soil formation and renewal Water resources and purification Natural Capital

1. Use Renewable Solar Energy As Energy Source 2. Recycle the chemical nutrients needed for life Lessons

Matter Cycles

You are responsible for knowing the

water, carbon, nitrogen, sulfur, and

phosphorus cycles

Know major sources and sinks

Know major flows

HYDROLOGIC CYCLE

Slide 34 Slide 34 Slide 34

Figure 4-28 Page 76 Precipitation to

land Transpirationfrom plants Runoff Surface runoff

(rapid)

Evaporation

from land _Evaporation

from ocean Precipitation to ocean

Ocean storage Surface

runoff (rapid) Groundwater movement (slow)

Rain clouds Condensation Transpiration

Evaporation

Precipitation Precipitation

HUMAN IMPACTS TO WATER

CYCLE

groundwater. (salt water intrusion and groundwater depletion)

2. Clear vegetation from land for agriculture, mining, road and building construction. (nonpoint source runoff carrying pollutants and reduced recharge of groundwater)

3. Degrade water quality by adding nutrients(NO₂, NO₃, PO₄) and destroying wetlands (natural filters).

MARINE CARBON CYCLE

Slide 35 Slide 35 Slide 35

Diffusion between atmosphere and ocean

Carbon dioxide dissolved in ocean water

Marine food webs

Producers, consumers, decomposers, detritivores

Marine sediments, including formations with fossil fuels

Combustion of fossil fuels

incorporation

into sediments sedimentationdeath, geologic timeuplifting over

sedimentation photosynthesis aerobic

respiration

TERRESTRIAL CARBON

CYCLE

Land food webs producers, consumers, decomposers,

detritivores

Atmosphere

(most carbon is in carbon dioxide)

Peat, fossil fuels combustion of wood (for

clearing land; or for fuel

sedimentation volcanic action

death, burial, compaction over geologic time

PHOTOSYNTHESIS

Photosynthesis: occurs within the chloroplasts of green plants. The photosynthetic membranes are arranged in flattened sacs called the thylakoids.

6CO₂ + 12H₂O C₆H₁₂O₆ + 6O₂ + 6H₂O light

(reactants) (products)

CELLULAR RESPIRATION

Cellular Respiration occurs in light simultaneously with photosynthesis. It occurs in the cytoplasm and

mitochondria.

It is the reverse reaction of photosynthesis.

Function = chemical energy release

C₆H₁₂O₆ + 6O₂ + 6H₂O 6CO₂ + 12H₂O+ chemical energy

HUMAN IMPACTS TO

CARBON CYCLE

1. Forest and brush removal has left less vegetation to absorb CO₂ through

photosynthesis.

2. Burning fossil fuels and wood produces CO₂ (greenhouse gas) that flows into the

troposphere. Trapping of CO2 in atmosphere enhances natural greenhouse effect and may contribute to climate changes that would

disrupt global food production, wildlife

IMPORTANCE OF CARBON

CYCLE

NITROGEN CYCLE

Slide 39 Slide 39 Slide 39

NO₃ – in soil Nitrogen

Fixation

by industry for agriculture

Fertilizers

Food Webs On Land

NH₃, NH₄+ in soil

1. Nitrification

bacteria convert NH₄+ to nitrate (NO₂–)

loss by leaching uptake by autotrophs excretion, death, decomposition uptake by autotrophs Nitrogen Fixation

bacteria convert N2to

ammonia (NH₃) ; this dissolves to form ammonium

(NH₄+)

loss by leaching

Ammonification

bacteria, fungi convert the residues to NH₃, this dissolves to form NH₄+

2. Nitrification

bacteria convert NO₂-to nitrate (NO₃-)

Denitrification

by bacteria

Nitrogenous Wastes, Remains In Soil

Gaseous Nitrogen (N₂) in Atmosphere

NO₂– in soil

NITROGEN CYCLE

1. Nitrogen fixation by cyanobacteria or

Rhizobium bacter.

2. Ammonification by decomposers and/or

nitrogen fixing bacteria.\

3. Nitrification by bacteria (NO₂ [toxic to

plants]to NO₃ [useable by plants]).

4. Assimilation (used by plants) OR

Denitrification by anaerobic bacteria in

HUMAN IMPACTS ON

NITROGEN CYCLE

1. WORLD War II, German chemist Fritz Haber developed the Haber Process and won the Nobel Prize. He developed

Commercial inorganic fertilizer in the laboratory. This was to solve global famine problems!

N₂ + 3H₂ 2NH₃

HUMAN IMPACTS ON

NITROGEN CYCLE CONT.

N

O gas is released into the atmosphere

by anaerobic bacteria on livestock

wastes and commercial fertilizers

applied to the soil. These act as

greenhouse gases and when N

O

HUMAN IMPACTS ON

NITROGEN CYCLE

Remove nitrogen from Earth’s crust when we mine for nitrogen-containing minerals for fertilizers

(ammonium nitrate (NH₄NO₃).

Deplete nitrogen from topsoil by harvesting nitrogen-rich crops (soybeans, alfalfa).

Leach water-soluble NO₃ ions from soil through irrigation.

Remove nitrogen from topsoil when we burn

HUMAN IMPACTS ON

NITROGEN CYCLE CONT.

Cultural Eutrophication – adding of

excess nutrients of NO2, NO3, and PO4,

from agricultural runoff (fertilizer and

Slide 40 Slide 40 Slide 40

Figure 4-32 Page 81

1920 1940 1960 1980 2000

G lo b a l n it ro g en ( N ) fi xa ti o n (t ri lli o n g ra m s) 0 50 100 150 200 Year

IMPORTANCE OF NITROGEN

CYCLE

Organisms use nitrogen to make vital organic

compounds such as amino acids, proteins, DNA, and RNA.

In both terrestrial and aquatic ecosystems, nitrogen is typically in short supply and limits the rate of

PHOSPHOROUS CYCLE

sedimentation settling out weathering

leaching, runoff _{DISSOLVED IN}

HUMAN IMPACTS TO

PHOSPHOROUS CYCLE

1. Humans mine LARGE quantities of phosphate rock to use in commercial fertilizers and detergents. Phosphorous is NOT found as a gas, only as a solid in the earth’s crust. It takes millions to hundreds of millions of years to replenish.

2. Phosphorous is held in the tissue of the trees and vegetation, not in the soil and as we deforest the land, we remove the ability for phosphorous to replenish globally in ecosystems. 3. Cultural eutrophication – ad excess phosphate to aquatic

IMPORTANCE OF

PHOSPHOROUS CYCLE

1.Phosphorous is an essential nutrient of both plants and animals.

2. It is part of DNA molecules which carry genetic information.

3. It is part of ATP and ADP) that store chemical energy for use by organisms in cellular respiration. 4. Forms phospholipids in cell membranes of

plants and animal cells.

SULFUR CYCLE

Acidic fog and precipitation Ammonium sulfate Animals Decaying matter Metallic sulfide deposits Ocean Dimethyl sulfide

Sulfur dioxide Hydrogen sulfide

Sulfur trioxide Water Sulfuric acid Ammonia Oxygen

Volcano

HUMAN IMPACTS TO SULFUR

CYCLE

Approximately 1/3 of all sulfur emitted into atmosphere comes from human activities. 1. Burning sulfur containing coal and oil to produce electric power (SOx = acid

deposition).

2. Refining petroleum – (SOx emissions)

IMPORTANCE OF SULFUR

CYCLE

1. Sulfur is a component of most proteins and some vitamins. 2. Sulfate ions (SO₄ 2- ) dissolved in water are common in

plant tissue. They are part of sulfur-containing amino acids that are the building blocks for proteins.

3. Sulfur bonds give the three dimensional structure of amino acids.