1

Nutrient CyclingLaws of Energy and Matter• Conservation of Matter

In any physical or chemical change, matter is neither created nor destroyed, but merely changes from one form to another

• Conservation of EnergyIn any physical or chemical change, energy is neither created nor destroyed, but merely changes from one form to another

• Law of Energy DegradationEnergy moves from an organized , useful form to a disorganized less useful form.

Atmospheric GasesNitrogen 78% Oxygen 21% Argon .93% Carbon Dioxide* .035% Neon .0018% Helium .00052% Methane* .00014% other gases ......

* these are consider "greenhouse gases"

Hydrologic (Water) Cycle

Precipitation

Precipitationto ocean

Evaporation

EvaporationFromocean

Surface runoff(rapid)

Ocean storage

Condensation

Transpiration

Rain clouds

Infiltration andPercolation

Transpirationfrom plants

Groundwater movement (slow)

Groundwater movement (slow)

RunoffRunoffSurface runoff (rapid)Surface runoff (rapid)

Precipitation

Nitrogen Cycle:

Forms of Nitrogen: N2 atmospheric nitrogen NO3- nitrate NO2- nitrite NH4+ ammonium NH3 ammonia N2O nitrous oxide NO nitric oxide NO2 nitrogen dioxide CH2N2O urea

Nitrogen Fixing: Changing Atmospheric N2 into usable nitrogen

Atmospheric: Lightning: causes N2 and O to combine in atm. dilute HNO3 formed and washed to surface .

Biological: Nitrogen fixing microorganisms. Specialized bacteria convert gaseous nitrogen to ammonia N2-+3H2-into-- NH3 (by cyanobacteria in the soil and water and Rhizobium bacteria in small nodules on roots of legume family of plants) Plants can use ammonia and ammonium ions or NO3- from the nitrification process below.

2

Nitrogen cycle (cont.)

• Nitrification: Changing Urea into usable NO3- most of the ammonia in soil is converted by specialized aerobic bacteria to nitrite (NO2-) and then to nitrate ions (NO3-) which plants take up as a necessary nutrient.

The Nitrogen Cycle

NO3-IN

SOIL

NITROGEN FIXATIONby industry

for agriculture

FERTILIZERS

FOOD WEBS ON LAND

NH3,NH4+

IN SOIL1.

NITRIFICATIONbacteria convert NH4

+ to nitrate (NO2

-)

loss by leaching

uptake by uptake by autotrophsautotrophs

excretion, excretion, death, death,

decompositiondecomposition

uptake by uptake by autotrophsautotrophs

NITROGEN FIXATION

bacteria convert to ammonia (NH3

+) ; this dissolves to form ammonium (NH4

+)

loss by leaching

AMMONIFICATIONbacteria, fungi convert the residues to NH3 , this dissolves to form

NH4+

2. NITRIFICATION

bacteria convert NO2

- to nitrate (NO3-

)

DENTRIFICATION

by bacteria

NITRO�GENOUS WASTES, REMAINS IN

SOIL

GASEOUS N�ITROGEN (N2) IN ATMOSPHERE

NO2-IN

SOIL

The Phosphorus CyclePlants take up phosphorus from soil using

their roots, Phosphorus is mainly in the phosphate form (PO4

3-). Plants uptake phosphate and incorporate it into their growth Phosphorous cycles through the ecosystem when plants are eaten, and then the organisms who eat the plants excrete waste or die and decompose.

The Phosphorus Cycle

GUANOFERTILIZER

ROCKS

LAND FOOD WEBS

DISSOLVED IN OCEAN WATER

MARINE FOOD WEBS

MARINE SEDIMENTS

weatheringweatheringagricultureagriculture

uptake by uptake by autotrophsautotrophs

death, death, decompositiondecomposition

sedimentationsedimentationsettling settling

outout leaching, leaching, runoffrunoff

weatheringweathering DISSOLVED IN SOILWATER,

LAKES, RIVERS

uptake by uptake by autotrophsautotrophs

death, death, decompositiondecomposition

uplifting over

geolgictime

uplifting over

geolgictime

miningmining

excretionexcretion

Human ImpactAs usual humans have

impacted all of the systems noted.

Human impactson nutrient cycles

• Water• Carbon• Nitrogen• Phosphorus

3

Ecosystems/ Ecological Processes

I. Definitions

II. Factors that Influence EcosystemA. Population and RegulationB. Range of Tolerance

1. Abiotic Factors2. Biotic Factor

III.Biotic Structure of the EcosystemA. Food ChainsB. Trophic Levels

Some definitions Biosphere: all living organisms and their environment

Ecosystem: grouping of plants, animals and microbes, etc. interacting with each other and their physical environment "ECO" = home

Community: all plants and animals inhabiting an area (suggests interactions)

Population: a group of individuals of the same species in an area

Species: a group of organisms where all members do or have the potential to interbreed and produce viable offspring

The Nature of Ecology

Organisms

Populations

Communities

Ecosystems

Biosphere

BiosphereBiosphere

Ecosystems

Communities

Populations

Organisms

Fig. 4.2, p. 72

Factors that Influence Ecosystems

Limiting Factors: anything that tends to make it more difficult for a species to live and grow, or reproduce in its environment.

Abiotic and Biotic: physical and biological factors can work in concert.

ToleranceThe degree a certain factor that an

organism can withstand is called tolerance.

• Optimum temperature• Range of tolerance• Limit of tolerance• Env. gradients

4

Limiting Factors: Env. gradientsRange of optimum

Popu

lation

size

Low High Temperature

Zone ofintolerance

Zone ofphysiological stress

Optimum range Zone ofphysiological stress

Zone ofintolerance

Noorganisms

Feworganisms

Lower limitof tolerance

Abundance of organismsFew

organismsNo

organisms

Upper limitof tolerance

ABIOTIC Limiting Factors

temperature water climate/weather soils (mineral component) terrainfire

BIOTIC Limiting Factors

competition:interspecific and intraspecific

predation/parasitismamensalismmutualism

BIOTIC Limiting Factors

competition:interspecific and intraspecific

Types of competition• Intraspecific (social behavior)

– Territoriality– Social hierarchy

• Interspecific– Competitive exclusion– Predator prey interactions– Parasitism– Amensalism– Mutualism

Intraspecific(social behavior)

TerritorialitySocial hierarchy

5

Agama sp.

Color changes to indicate

dominant individuals

Social hierarchy

Familial groups

Matriarchal societies

6

Interspecific Competition

• Competitive exclusion• Predator prey interactions• Parasitism• Amensalism• Mutualism

• Bromus tectorum

European starling

Competitive exclusion

Zebra mussels

Avoiding/Reducing Competition

temporal separation

• Feeding specializations

7

Avoiding/Reducing Competition

• Behavioral specializations

Predator prey interactions

Fig. 9.8, p. 203

Popu

lation

size

(tho

usan

ds)

160

140

120

100

80

60

40

20

01845 1855 1865 1875 1885 1895 1905 1915 1925 1935

Year

Hare

Lynx

5,000

4,000

3,000

2,000

1,000

500

Num

ber

of m

oose

1009080706050403020100

1900 1910 1930 1950 1970 1990 2000

1997Year

Num

ber of wolves

Moose population

Wolf population

Parasitism

Amensalism

8

Mutualism

III. Biotic Structure of the EcosystemA. Food ChainsB. Trophic Levels

Biotic Structure of an Ecosystem

• Producers: (autotrophs)• Consumers: (heterotrophs)

– Primary:– Secondary:– Tertiary:

• Decomposers:

Biotic Structure of an Ecosystem

• Producers: all plants with chlorophyll that photosynthesize:(autotrophs)

Consumers:Feed on producers orother consumers (heterotrophs) • Primary: feed on producers (herbivores)

• Secondary:• feed on primary consumers(carnivores)

• Tertiary:…..

Decomposersfeed on detritus(usually a bacteria or fungus that feed on dead producers, consumers, etc.)

9

MushroomWoodreduced

to powder

Long-hornedbeetle holes

Bark beetleengraving

Carpenterant

galleries

Termite andcarpenter

antwork

Dry rot fungus

Detritus feeders Decomposers

Time progression Powder broken down by decomposersinto plant nutrients in soil

DecomposersThe Biotic Components of

EcosystemsProducers(autotrophs)photosynthesis

Consumers(heterotrophs)

Decomposers

Heat

Heat Heat

Heat

Heat

AbioticAbiotic chemicalschemicals(carbon dioxide,(carbon dioxide,oxygen, nitrogen,oxygen, nitrogen,

minerals)minerals)

ProducersProducers(plants)(plants)

DecomposersDecomposers(bacteria, fungus)(bacteria, fungus)

ConsumersConsumers(herbivores, (herbivores, carnivores)carnivores)

Solarenergy

Energy efficiency

As energy is transferred through the food chain , energy is lost to heat, therefore only about 10% of energy is actually transferred between trophic levels.

1% captured by primary producers (99% lost as heat)

10% plant energy passes on to herbivores

~10% passed on to primary carnivores

~10% passed on to secondary carnivores

Heat

90% lost

90% lost

As we getting higher in trophic levels it takes more energy to maintain the higher levels, on the order of 10X per level.

Food Webs and Energy FlowFood chains/Food Webs

Heat Heat Heat Heat

Heat

Heat

Heat

First TrophicLevel

Second TrophicLevel

Third TrophicLevel

Fourth TrophicLevel

Solarenergy

Producers(plants)

Primaryconsumers(herbivores)

Tertiaryconsumers

(top carnivores)

Secondaryconsumers(carnivores)

Detritvores(decomposers and detritus feeders)

Ecological Pyramids

Pyramid ofenergy flow

Ecologicalefficiency

Pyramid ofbiomass

Pyramid ofnumbers

Heat

Heat

Heat

Heat

Heat

1010

100100

1,0001,000

10,00010,000Usable energyUsable energyAvailable atAvailable at

Each tropic levelEach tropic level(in kilocalories)(in kilocalories)

ProducersProducers(phytoplankton)(phytoplankton)

Primaryconsumers

(zooplankton)

Secondaryconsumers(perch)

Tertiaryconsumers(human)

Decomposers

Fig. 4.20, p. 85

10

Food web Complexity

Humans

Blue whale Sperm whale

Crabeater seal

Killerwhale Elephant

seal

Leopardseal

Adéliepenguins Petrel

Fish

Squid

Carnivorous plankton

Krill

Phytoplankton

Herbivorouszooplankton

Emperorpenguin