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Applied Ecology

Professor Crerar

Doctoral CandidateEnvironmental Science and Policy



Definitions of Ecology

³the scientific study of the interactions and abundance of organisms´(Andrewartha 1961)

³the study of structure and function of nature´ (Odum 1971)

³the study of the adaptation of organisms to their environment´ (Emlen1973)

³the scientific study of the relationships between organisms and their environments´ (McNaughton and Wolf

e 1979)

³the study of organisms and their environment²and theinterrelationships between the two´ (Putman and Wratten 1984)



How Does Applied Ecology Fit

Into These Definitions?



Course Goals

Learn (and review) basic concepts of Ecology.

How do humans impact ecological systems?

Integrate concepts from various disciplineswithin the field to gain broader understanding of

the environment.

What can we (scientists, planners, policy

makers) do to mitigate our impact on thesurrounding environment?



The Global Situation

Increasing human population and

industrialization.

Increasing environmental stress.

Ecological change

and evolutionary

response.



The Consequences

Increasing conflicts among human groups.

Human conflicts are settled by:

Negotiation

Economics

Warfare

Ecological sciences can help predict outcomes of

various actions to help resolve conflicts.



Energy

Energy is the ability to do work.

Described by Laws of Thermodynamics

1st: Energy can be neither created nor

destroyed.

2nd: In any energy transfer, some part is ³lost´

as low temperature heat.

Energy flows from concentrated areas to

dispersed areas.



Energy

Organisms are able to

use energy to maintain

their complexorganization.

The concentrated

energy source for mostbiological processes is

the Sun.

3D Sun Image



The Sun

Less than 1% of the energy flowing from

the Sun strikes the Earth¶s upper

atmosphere. This averages 2 cal/cm2/min.

About 25% is reflected.

About 25% is absorbed and reradiated. About 50% reaches the land or water

surface of the Earth.



The Sun

Most of the absorbed energy is reradiated as

heat.

Less than 2% is absorbed by photosynthetic

pigments and used to split water molecules.

H+ ions combine with CO2 to form an energy-

rich molecule.



The Sun



Primary Productivity

Definition:

formation of energy-rich carbon molecules by

organisms using physical forms of energy

A rate function.

Units can be calories, joules, or biomass per

unit of time. Total formed is gross primary production

(GPP).



Gross Primary Productivity

Cellular respiration is used to maintain

the organism.

usually ~90% of GPP

What is left is called net primary

production (NPP).

This accumulates as added biomass or newindividuals (reproduction).

This is available as food for the next trophic

level.



Net Primary Productivity (grams/square meter/year)

Tropical rain forest ~2000

Temperate deciduous forest ~1250

Boreal forest ~800

Tropical savanna ~750

Temperate grassland ~600

Oceans ~150

Total Earth ~3550



Food Supply for Humans

6,792,419,840(12/28/2009 1:22pm)

Projected to reach 8 - 15billion by 2100.

There were 1.5 billion haof arable land in 2000.

Therefore, each hectaremust feed 4 persons.



Food Energy Production( 109 joules/ha/yr)

Low Input Agriculture relies on as little energy input

as possible, both in fuel and fertilizer.

Low Input System Energy Production:

Commercial fishing (1986-1995) 0.004

Migratory pastoralists (Kenya) 0.025

Shifting cultivation (Papua) 1.4 Open field, Medieval England 5

Fields in Southern India 8




High Input Agriculture use both more fuel and

more fertilizer.

High Input Systems:

Cattle in England pasture 5

Wheat in Canada 31

Wheat in United Kingdom 106




Wild Ecosystems are those not influenced by human

activity

Wild ecosystems 200



Food Energy Production

Low input systems feed only a smallpercentage of humans.

Only high input grain cultivation canfeed a significant percentage.

These monocultures are heavily³subsidized´ from external energysources.



Crop Yield Increases

Larger proportion of growth goes into

desired product.

Growth begins earlier and persists later.

Growth to product occurs more rapidly,

allowing multiple crops/year.

Able to use more fertilizer to increaseproduct.



Crop Yield Increases

Increased fertilizer

application.

Increased water availabilitythrough irrigation.

Improved control of

competing weeds, pestsand diseases.

Colorado Sorghum



Evolution of Photosynthesis

4.6 byBP no free oxygen (O2)

Formation of energy-rich chemicals by anaerobic

chemosynthesis or chemical evolution.

3.2 byBP photosynthesis evolved

600 myBP O2 is 1% of current

400-350 myBP 10% of current 250 myBP 100% of current



Evolution of Photosynthesis

Role of incomplete respiration of energy in

O2 accumulation.

Carboniferous Period 350-280 myBP

Coal, natural gas, petroleum

Balance of O2 and CO2 in world system.



Global Carbon Cycle

Carbon pools in various places in the

environment (in gigatons of carbon):

Animal bodies less than 1 Plant and algal bodies 603

Atmosphere 800

Detritus, DOC 3000

Fossil fuels 10,000

DIC in the ocean 40,000

Marine sediments millions

Continental crust rocks millions



Carbon Flow Rates

Inputs into the atmosphere (x 109 tons/yr)

Cement manufacture 0.2

Deforestation 1 - 2

Burning fossil fuels 5.3 - 6

Removals from the atmosphere

� Forest expansion 0.5

� Increased vegetation biomass 1.3� Increased diffusion into ocean 2.0



Global Carbon Cycle

The carbon cycle is a gaseous cycle with

sedimentary components.

It is tied to energy flow in ecosystems.



Global Carbon Cycle

It is unusual in that the atmospheric reservoir

is the smallest (atmosphere versus land

versus oceans), yet is the most important.

Oceans represent an active reservoir for

carbon and an active exchange with

atmosphere.



Global Carbon Cycle

Short term fluctuations are tied to

photosynthesis/respiration patterns, both

daily and seasonally.

Long term changes are now tied to fossil

fuel emissions.



Global Carbon Cycle

Pools of Carbon:1. Land Masses: 2.6 X 1016 tons

Dominant Inorganic Form: carbonates (MgCO3; CaCO3) Dominant Organic Form: fossil fuels (peat; coal; oil)

2. Oceans: 2.7 X 1013 tons

(Which is 0.1% of the amount in land masses)

Dominant Form: Carbon Dioxide (CO2)

3. Atmosphere: 7.0 X 1011 tons

(Which is 0.003% of the amount in land masses)

Dominant Form: Dissolved CO2; CO32+

2222



The Water Cycle

Over 97% of water on Earth is in salty seas.

Of the remaining 3%, 2/3 is stored in glaciers, icecaps and permafrost or lies deep underground.

Freshwater is unevenly distributed

By continent: the Americas have the largest amount

Oceania the least. Per capita:

Asia has the least



The Water Cycle

An adequate supply of water is about 13 gallons

per person per day.

10% for drinking 40% for sanitation and hygiene

30% for bathing

20% for cooking

In US and Canada we consume 150 gallons per person per day.

In UK they use 20% of that.



The Water Cycle

People appropriate about 50% of the world¶s

available fresh water.

The UN estimates that by 2025, 48 countries

(2.8 billion people) will face fresh water

shortages.



Nitrogen Cycle

The global nitrogen cycle is unique in that it

consists of:

1. A large well-mixed pool of N2 in the

atmosphere;

2. A smaller quantity of nitrogen bonded to carbon,

oxygen and/or hydrogen that cycles among

plants, animals, soils, sediments, and solutions;and



Nitrogen Cycle

Humans have extraordinarily affected the

global nitrogen cycle.

Background terrestrial fixation of nitrogen is

100 Tg per year globally. (One Teragram (Tg) = 1012 grams)



Nitrogen Cycle

When the first microbes appeared about 3.5

billion years ago, none had the ability to fix

nitrogen.

Nitrogen was only available when nitrate

(NO3-) was formed during lightning strikes

and the small amount produced could

support only a limited amount of life.



Nitrogenase

Nitrogenase is a tetramer

protein consisting of two

identical Fe4S4 cluster and

FeMo cluster subunits.

It allows nitrogen fixation by

bacteria.



Nitrogen Cycle

Nitrogenase uses large

amounts of ATP as an energy

source, making nitrogen

fixation an expensivemetabolic process.



Nitrogen Cycle

The relationship between the bacteria and

the plant is highly specific.

The bacterium that invades and produces

nodules in clover will not induce nodules on

the roots of soybeans.

The legume plant family includes peas,

soybeans and most other beans.



Phosphorus Cycle

Phosphorus (P) is found mainly in the Earth'scrust and sediments, so it is a good exampleof an element with a sedimentary (imperfect)

cycle in ecosystems.

The major biologically active form of P is asphosphate (PO4

-3).



Phosphorus Cycle

The main reserves of phosphate are in rock,

from which elements are leached for

biological uptake.

Its movement is linked directly with the

movement of water (called the hydrologic

cycle).



Phosphorus Cycle

This results in a more-

or-less one-way

transfer of P from landto the oceans, where it

sinks and remains

unavailable for long

intervals as sediments.



Phosphorus Cycle

Because phosphate ions are held tightly onthe surfaces of soil particles under most pH

conditions, the absorption of P from soils isusually difficult.

Fungi associated with plant roots are able tofacilitate the acquisition of phosphate ions.



Phosphorus Cycle

In aquatic systems, P is also usuallyavailable in low quantities because of the

low solubilities of P compounds in water and the loss of P to sediments.

Man has intervened in the P cycle globally

to an ever-increasing extent in a number of different ways.



Phosphorus Cycle

1. Mining of phosphate rock, making Pavailable that would otherwise be tied

up in sediments.2. P-rich effluent from municipal

wastewater treatment causes unusuallyhigh levels of photosynthetic activity in

aquatic systems, causingeutrophication, or aging of local bodiesof water.



Phosphorus Cycle

In Virginia, tertiary

wastewater

treatment is

required to reducethis impact.



Other Cycles

Sulfur ± effects acid rain

Potassium ± changed because of fertilizer

Magnesium ± effected by concrete manufacture

Copper ± effected by mills

Zinc ± vital for cellular processes

Iron ± vital for blood manufacture in humans



Questions?

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