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 Rain Acid Rain-DC 2.3Coal Combustion and Acid Rain 2.04 BBC Acid Rain 4.5

DDT 1962 CH54#7

Persistence, 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 condition in which the growth of water plants takes place in excess amount “Enrichment” Excessive richness of nutrients

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). Water Quality Testing Low DO-Puget Sound 4.35 Dead Zone 2.36 Dead Zones 3.39

Nitrogen Cycle How organisms convert (fix) unusable nitrogen (N 2 ) 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

1.Nitrogen Fixation & Nitrification: Bacteria!! Nitrogen Fixing Bacteria in nodules and in soil convert N 2 to soluble form (ammonia); Others convert this ammonia to forms we can use 2.Assimilation- Nitrates are taken in by plants *NO bacteria needed!! 3. Decomposition and Denitrification- Bacteria and others convert N back to ammonia in soil and to gas (N 2 )

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 Sinks and Sources

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 “Anthropogenic” - Environmental pollution from human activity

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

THE PHOSPHORUS CYCLE Needed for: – DNA – Cell Membr. – ATP No gaseous state; released from rocks… released by weathering

Species Richness vs Diversity Understanding 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 A Species # of individuals A 59 B 12 C 11 D 10 E 5 F 3 Total 100 Community B Species # of individuals A 21 B 20 C 19 D 14 E 13 F 13 Total 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.

Clips Fast Food for Polar Bears 7.29 Bill Nye Crossfire Debate 13:57