Chapter 25 : Ecology.
Ecology is the study of the relationships of organisms to each other and to their environment.

Regional issues

Acid rain is produced by burning fossil fuels, which produces nitric and sulfuric acids. Map
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       Natural unpolluted rain is        pH 5.5
       Rain in Jacksonville averages     pH 4.5
       In the NE states rain can be      pH 3.5
```
Acid rain (especially a pH of less than 4) can kill fish and plants. One solution is to clean emissions from large pollutors like power stations: Scrubbers
Water pollution from pesticides, paper mills and fertilizers is a big problem. Beach closings in Florida
Florida's beaches are now routinely checked for pollution. Florida.
Plants could be used in bioremediation to soak up polluants. For example Pteris in Florida soaks up arsenic that was used in making pressure-treated lumber. Fern and arsenic
Wetlands provide habitat for a variety of organisms, and treat wastewater. Wetlands

Global issues

Ecological principles
A population is a group of individuals of the same species living in a particular area, for example the population of pitcher plants at UNF. A community is several different species living in the same location, for example a north Florida pine forest. The ecosystem is the living organisms and their physical environment, for example the Everglades ecostystem.

Ecosystems have food chains or trophic levels going from producers (plants) through primary consumers (herbivores) to secondary and tertiary consumers (carnivores). Typically only 10% of the energy in one trophic level is passed on to the next trophic level. Humans can be primary consumers or secondary consumers.

In contrast to energy, chemicals are recycled in the ecosystem. The main biological chemicals are carbon, nitrogen, phosphorus and water.

Communities are often affected by disturbances (episodes that damage communities) such as fire, volanoes, floods etc. Slowly species will recolonize a disturbed area in an ecological succession. Succession

Primary succession is when a community moves into an area without soil eg bare rock. Mosses are later replaced by grasses then trees.

Secondary succession is when a community returns to an area that still has soil eg after a forest is clearcut.

Humans affect many of these natural cycles, for example fertilizers and sewage can pollute rivers and groundwater. Also burning gas, coal and oil all releases carbon dioxide into the atmosphere. The level of carbon dioxide is slowly increasing in the air and this causes a "greenhouse effect" that is warming the entire planet. CO2 trends Global warming Data
2005 warmest on record
Warming temperatures will cause the ocean level to rise, which is a threat particularly in Florida. 2006 prediction.

One solution to this would be to generate electricity from biomass (grasses or trees), which would overall be "Carbon neutral" : Biofuel

In 2005 the Kyoto treaty came into effect. This was signed by over 160 countries, and requires them to reduce their emissions of carbon dioxide and other greenhouse gases. The US has not ratified the treay. Kyoto treaty Carbon dioxide

A different problem is air pollution by CFCs (used in air conditioners) which is reducing the thickness of the ozone layer high in the atmosphere. The ozone layer protects us from ultraviolet ( UV ) light. This UV light causes skin cancer and cataracts in the eye. Skin cancer is the most common type of cancer in the US.
A worldwide treaty banning the use of CFCs has slowed this damage to the ozone layer, and within 50 years the "ozone hole" should be repaired.

Biodiversity and Conservation

Many species of plants and animals have either recently gone extinct or are in danger of extinction. This is mainly because of:

1) Habitat destruction : people cut down forests for farmland, or drain wetalnds to build houses etc. If development continues at its present rate, all buildable land in Florida will be used up by 2060.

2) Introduced species : often replace native species. For example: Brown tree snakes in Guam have caused the extinction of many bird species, and are so common they cause electrical outages by climbing up power poles. Snakes Kudzu The cost in the US.

Conservation groups try to slow down or reverse the loss of biodiversity, for example by protecting "biodiversity hot spots" small areas where there are many endangered species. Biodiversity.

One reason why it is important if a species becomes extinct: the "rivet" hypothesis. An airplane is held together with thousands of rivets, if one or two are removed the plane is fine. But eventually if too many rivets pop out the wing, or engine, may come off. Similarly if one or two species go extinct it may not have much effect, but if enough species vanish it may ruin the whole ecosystem.

Last edited November, 2009 by David Byres, dbyres@fscj.edu