BIOGEOCHEMICAL CYCLES,And

HUMAN IMPACT

Man, Steve Cutts 3.36

Biogeochemical Cycles

• Water Cycle (Hydrological)• Phosphorus Cycle• Carbon Cycle• Nitrogen Cycle

THE WATER CYCLE

X 1000cubic km

Acid Rain

pH of ‘Normal Rain’? ~5.6

Problems Caused by Acid RainAcid Rain-DC 2.3Coal Combustion and Acid Rain 2.04BBC Acid Rain 4.5

the condition in which the growth

of water plants takes place in

excess amount

“Enrichment”

THE HUMAN IMPACT ON

ECOSYSTEMS

Pollution and Overpopulation can seriously damage the health

of an ecosystem (the living and non-living factors in an area).

WaterQualityTesting29.13

Low DO-Puget Sound 4.35Dead Zone 2.36 Dead Zones 3.39

DDT 1962CH54#7

CH54#7Persistence, Bioaccumulation, Biological Magnification

• When substances like mercury and pesticides (herbicides, insecticides) enter a river, etc. from factory waste, the entire food web can be destroyed.

• Negative health effects

• Persistence: Characteristics of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by a natural process.

• Biological Accumulation: Buildup of a persistent toxic substance such as pesticides, in an organisms body.

• Biological Magnification: The increase in concentration of a persistent toxin in the tissues of organisms at higher trophic levels. (The larger the animal, the greater the accumulation of toxin) HW54-7

THE PHOSPHORUS CYCLE

Needed for:– DNA– Cell

Membr.– ATP

No gaseous state; released from rocks…released by weathering

Nitrogen CycleHow organisms convert (fix) unusable nitrogen (N2) in the atmosphere to usable

nitrogen to make proteins

1. All organisms need Nitrogen to build proteins and for growth. Our atmosphere is made up of what % of Nitrogen?

2. 78% of the atmosphere is Nitrogen, but organisms cannot use it. The nitrogen needs to be changed (or “fixed”) into a useable form. Why do we need it? How do we get it?

3. Nitrogen fixing bacteria, on the roots of plants, (Legume or bean plants like peanuts, soy, alfalfa) change the nitrogen to a usable form (ammonia/nitrates)Symbiotic Type?

4.Animals then eat the plants/plant eaters to get the needed nitrogen

Legumes• Legumes are plants

whose roots contain nodules that have nitrogen-fixing bacteria.

• Used in crop rotation to increase nitrogen in nitrogen-depleted soil

Examples: Peanuts, soy, clover

THE CARBON CYCLE

THE GREENHOUSE EFFECT

FOSSIL FUELS• Fossil fuels - made from organisms that died

millions of years ago and were buried• ”non-renewable”, meaning there is a limited

supply.• Examples:– Coal, oil and gas

Renewable Resources• Resources that have unlimited supply.• Often considered “green”• Often do not release harmful pollutants and/or carbon dioxide

Examples: Wind, solar, geothermal, hydroelectric

(water) *NUCLEAR

The Ozone Layer

Species Richness vs DiversityUnderstanding the Difference Between Species Richness and Species Diversity Consider the following data from samples of organisms obtained from two different biological communities, A and B.Community ASpecies # of individualsA 59B 12C 11D 10E 5F 3Total 100

Community BSpecies # of individualsA 21B 20C 19D 14E 13F 13Total 100

In community A one species, Species A, numerically dominates the other five species. In community B the six species are more evenly represented. Because of this difference, community B would be considered to be more ‘diverse’ than community A despite both communities having the same total number of individuals and the same number of species. Thus, when measuring species diversity the relative abundance of each species must be taken into account.

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