Life+on+Earth

**Bacterial Environments:**
= Content of page: =
 * Select 1 example from Bacteria (eg cyanobacteria, stromatolites, nitrogen fixing bacteria) OR Archaea (eg methanogens, halophiles, thermophiles, deep sea bacteria)
 * 1) Outline the characteristics of the procaryote you selected.
 * 2) Describe the environments that this procaryote lives in __today__.
 * 3) Outline the role of this procaryote in its environments.
 * 4) Describe the __past__ environments that this procaryote is thought to have lived in.

Cyanobacteria



Cyanobacteria or blue-green algae are a type of bacteria that obtains its energy through the process of photosynthesis. They are unicellular and live in colonies forming either filaments, sheets or hallow balls. Some of the colonies of cyanobacteria have the ability to differentiate into three different cell types.

Cyanobacteria are one of the largest and most important groups of bacteria found on earth and were very important in the development of oxygen in early earths atmosphere, as they released oxygen into the ocean which eventually escaped into the atmosphere creating the ozone layer and making it possible for life to form. Cyanobacteria is primarily found in the ocean, but can be found in freshwater areas (inland lakes) and in arid areas such as in biological soil crusts.

Fossil evidence indicates that Cyanobacteria existed approximately 3.3 billion years ago from Archaean rocks on Western Australia. They were responsible for the initial conversion of the earths atmosphere from an anoxic to oxic state.

Cyanobacteria are photosynthetic organisms. they are the primary producers at the bas of the food chain within their ecosystem. Cyanobacteria generate large quantities of oxygen because of their role as primary producers. Stromatolites are structures are structures made by communities of Cyanobacteria. their abundance and ability to photosynthesis has contributed to the reduction of carbon dioxide and the increase of oxygen in the earth's atmosphere. = Thermophiles =

What is a Thermophile?

 * A thermophile is a microorganism which lives and grows in extremely hot environments that would kill most other micro organisms
 * They can be prokaryotes or eukaryotes
 * Their most suitable habitat is geothermal and is in between 50 and 70 degrees celsius and will not grow below 20 degrees celsius
 * Some thermophiles are fungi
 * Thermophiles can reproduce sexually or asexually

Where they live today

 * Thermophiles live in places such as deep sea, hydrothermal vents inside volcanoes and in the hot spring of yellowstone park
 * These microorganisms are able to survive in high concentration of heavy metals and sulfides[[image:http://yellowstonethermophiles.com/images/Grand_Prismatic.jpg width="270" height="180" align="right" caption="external image Grand_Prismatic.jpg"]]
 * All thermophiles require a hot water environment, but some thrive in more than one extreme, such as those with high levels of sulfur or calcium carbonate, acidic water, or alkaline springs

Role of Thermophiles

 * Thermophiles turn organic matter into a source of nutrients for living microorganisms and plants to use as food
 * Some types of thermophile can be used in DNA finger printings for criminal cases

Previous Environments
> Characteristics of Halophiles: __//** > > Halophiles are aerobic organisms containing a system to produce energy. They are predominantly red**// in colour which is caused by a pigment called Bacteriohodopsan, which enables them to photosynthesis and produce energy without oxygen. Halophiles are coated with a special protein covering which is used to allow certain levels of saline/salt into the cell. This covering helps to seal in water with the right level of saline. These microorganisms use osmotic pressure and chemical substances like sugars, alcohols, amino acids to help control the amount of salt inside the cell. Healthy cells keep the pressure the same on the inside and outside of the cells. The carotenoids give them a pinkish colour which allows them to be visible to the human eye. //** > > > > **// __Today's Environment Halophiles:__ //** > Halophiles are found in environments where the salt concentration is extremely high. Such as, the Dead Sea in the Middle East, The Great Salt Lake in the USA and evaporating ponds of saline waters. The saline content in Halophilic environments is usually 10 times the saline/salt content of normal ocean water. > || The Dead Sea || > || The Great Salt Lake || > > > **// __The role of Halophiles in its present day environment:__ //** > In their ecosystem Halophiles are a part of the food chain and are consumed by filter feeders. Very little is known about the Halophiles roles in the environment and more research is needed. > > **Methanogens**: > > Methanogen activity creates most of the Earth's natural gas deposits > > **Role in the Ecosystem** > > > Cows produce methanogens/methane gas > and are major influences on the rising levels > of the gas. > > > 3.5 to 3 billion years ago, the atmospheric methane levels began to rise, forming an organic haze. > This is because methanogens secrete CH4 as well as CO2. This rise of the CH4 levels added to the > greenhouse warming effect. Methane is a powerful greenhouse gas, which warms 21 times more than > CO2. Methanogens live 100 times longer in an anoxic atmosphere than they do into today's environment > > The combination of high levels of methane and CO2 which made up the Earth's early atmosphere, created > a greenhouse effect which has caused the planet to warm. > > Methanogens have been found in several extreme environments on Earth, buried under kilometres of ice in > Greenland and living in hot, dry desert soil. They can still reproduce from temperatures of 15 to 100 degrees > Celsius. They are known to be the most common prokaryotes archaebacteria in deep subteranean habitats.
 * In the early earth thermophiles were more abundant in volcanoes and hot springs because they were adapted to these hot environments
 * **//__HALOPHILES
 * [[image:procaryotes:dead-sea.jpg width="330" height="231" caption="The Dead Sea"]] ||
 * [[image:procaryotes:salthalo1.jpg width="191" height="224" caption="The Great Salt Lake"]] ||
 * are a type of bacteria that uses hydrogen gas and carbon dioxide to generate energy and make sugar
 * are found in bogs and deep soils, marine and freshwater sediments, the intestinal tracts of herbivores and in sewage treatment facilities
 * are Anaerobic and cannot tolerate exposure to oxygen
 * Methanogens play a role in the recycling of carbon and are important decomposers.
 * The methane they release into the atmosphere contributes to the carbon cycle.
 * There has been a large rise in the amount of methane in the Earth's atmosphere in recent years
 * The increase of domestic cattle is the reason for this increase.