B1 Biogeochemical Systems

Carbon Cycle

What elements makes life possible?

Carbon based life Key component of all known naturally occurring life on Earth Unique properties make it ideal for construction of complex molecules Bond with four other atoms Bonds with itself Very stable

Formation of Earth Where Where do does all carbon all this atoms come carbon from? come from?

Carboniferous Rainforest Collapse Unknown event caused climate change killing most of earths rainforest Dead vegetation covered the surface of the earth, much of which became covered with water The material decayed, it was compressed, heated, and eventually it became coal

Fast forward

Coal is burned to boil water to produce steam that turns turbine

Made in Stars

Present when earth was formed

Incorporated into plant tissues

Incorporated into animal tissues

Formed Coal Deposits

Released by Coal Burning plants

Circulate in the atmosphere (CO 2 )

What`s the deal

Photosynthesis

The production of one sugar and six oxygen molecules using 6 carbon dioxide molecules from air 6 water molecules from roots

Main process of removing gaseous carbon from atmosphere and introducing it into food chains where it becomes part of living organisms

Photosynthesis TED

Cellular Respiration

The production of energy, six carbon dioxide, and six water molecules using 1 sugar that we eat 6 oxygen molecules that we breathe Both these molecules must travel to a mitochondria somewhere in the body

Main process for releasing carbon, as carbon dioxide into surrounding air or water.

Why are they important Photosynthesis and Cellular Respiration are direct opposite processes of each other?

Photo and Respiration

Cellular Respiration: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O Photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2

Carbon Cycle

Changing Times Carbon cycle left undisturbed can deal with change In the past, levels have natural changed

Carbon dioxide increasing

Burning fossil fuel primary source of increased CO 2 in the atmosphere Without human interference, fossil fuels would leak out by volcanic activity We accelerated this process

Release large amounts of carbon that took millions of years to form Released 8.4 billion tons of carbon in 2009 One ton for every person on the planet and then some!

The carbon cycle can remove roughly half of this each year The remainder stays in atmosphere How is Carbon removed?

Photosynthesis

Forests act as sinks of carbon, removing extra from the atmosphere

Trees in forest contain more carbon than 10 years worth of human produced greenhouse gases Carbon stored in the wood returns to the atmosphere

Deforestation

Reasons for Farms and pasture land Timber for construction and fuel To build roads improve transportation

Cover 7% of Earth s dry land Habitat for half of all species on earth high biodiversity Many not discovered yet Many species extremely specialized

Brazil lost 163,000 square miles of forest

400 ppm world According to reports from the Mauna Loa Observatory, worldwide CO2 averages for last week were 397.92 ppm. Daily measurements showed CO2 levels exceeding 398 ppm. And it appears likely that monthly CO2 averages for March will be in the range of 397.5 ppm. At this pace, it appears that worldwide CO2 will come very close to touching 400 ppm averages in May of this year and will certainly exceed the 400 ppm threshold by 2014. Scientists have set the safe limit for worldwide CO2 levels at 350 ppm. We are currently far in excess of that number. The last time CO2 was 400 ppm was between 2-3 million years ago. So a sustained CO2 of this level over long periods would continue to drive radical environmental changes. A world with average CO2 of 400 ppm, according to paleoclimate, eventually becomes 2-3 degrees hotter than today. Sea levels in such a world rise, over time, and eventually stabilize between 15 and 75 feet higher than today.

The average pace of CO2 increase over the past ten years is more than 2 ppm each year. This pace of increase is many times faster than any period in the geological record. At 400 ppm, worldwide CO2 will be about 125 ppm higher than in 1880. During the ice age, worldwide CO2 averaged around 190 ppm. The jump from 190 ppm to 275 ppm set off changes in Earth s heat balance that increased global temperatures by more than 5 degrees Celsius, melted the great Laurentide ice sheet, and caused sea levels to rise by scores of feet. Under business as usual fossil fuel burning, scientists expect world CO2 levels to reach between 600 and 850 ppm by the end of this century. Such high levels of CO2 have not been seen for 6 million years or more. Further, the massive forcing a jump to 600 to 850 ppm would induce would likely result in feedbacks that continue to push worldwide greenhouse gasses even higher. Many scientists believe that this would result in enough heat increases to make the world very hostile to life.

Natural Changes Climate has changed Planet received more or less sunlight Atmosphere changes Variations in sun s energy

What is Global Warming Rapid increase in Earth s average surface temperature over the past century primarily due to greenhouse gas emissions

Global Warming - Leo

Global Warming 101

The Greenhouse Effect The CO 2 in the atmosphere acts as a layer of insulation Higher CO 2 levels produce a larger layer Thicker insulation does a more effective job of keeping the planet warm

Effects of increased atmospheric CO 2 Atmosphere Important for controlling Earth s temperature Ocean Land

Ocean Acidification Large amounts of the CO 2 in the atmosphere finds its way into oceans, where it lowers the ph of the water (more acidic). Harmful effects on the health of the ocean

The Acid Test

What does a warmer earth look like?

How is Today s Warming Different from the Past? Earth has experienced climate change in the past without help from humanity. We know about past climates because of evidence left in tree rings, layers of ice in glaciers, ocean sediments, coral reefs, and layers of sedimentary rocks. For example, bubbles of air in glacial ice trap tiny samples of Earth s atmosphere, giving scientists a history of greenhouse gases that stretches back more than 800,000 years. The chemical make-up of the ice provides clues to the average global temperature.

Using this ancient evidence, scientists have built a record of Earth s past climates, or paleoclimates. The paleoclimate record combined with global models shows past ice ages as well as periods even warmer than today. But the paleoclimate record also reveals that the current climatic warming is occurring much more rapidly than past warming events. As the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years. In the past century alone, the temperature has climbed 0.7 degrees Celsius, roughly ten times faster than the average rate of ice-age-recovery warming.

Alterative Explanations Variations in Solar Radiation Wobbles in the Earths orbit Volvanic Eruptions

Nitrogen Cycle

Living things need nitrogen Key element in Chlorophyll, essential for photosynthesis Proteins, building blocks of muscle tissue Promotes plant growth, available nitrogen to form chloroplasts

Nitrogen Fixing Bacteria Plants cannot use nitrogen gas (N 2) but they need nitrogen. They use nitrogen that has been fixed ; incorporated into compounds with other elements by bacteria. Legumes are used to fixed N 2 into fields Alfalfa

Animals consume plant tissue (with nitrogen) and create animal tissue These animals may be consumed, the animal tissue will be broken down and used to produce new animal tissue Nitrogen travels up the food chain

When any animal dies Decomposer break down the tissue and return the nitrogen to the environment This nitrogen is available to once again become part of a plant and enter a food chain

The Main Idea? Nitrogen cycles in the environment in a similar manner as carbon, get it!

Eutrophication

Where is Lake Winnipeg?

What is it? When a body of water acquires high concentration of nutrients, that promote excessive growth of algae. Natural slow occurring process in all lakes, accelerated by human interference

Isn t this a good thing? Algae supports aquatic food chains. The more algae present the more consumers the ecosystem can support. Some lakes have been intentionally eutrophied to increase algae to support increased fish population.

Why it s bad Nutrient levels rise Nitrogen, and phosphorus

Phytoplankton populations explode ; algal bloom

Thick algae layer covers the surface of the water, preventing sunlight from entering the water column Algae in water begins to die from inability to perform photosynthesis without sunlight; sinks to bottom

Dead algae on lake bottom begin to be decomposed by bacteria; which consume much of the remaining oxygen.

Species that require oxygen die; large fish kills. Large declines in fish populations.

Decomposition (break down) of algae returns phosphorus and nitrogen into the environment increasing these levels even further.

What can be done? For many years it was unclear which nutrients had the greatest impact on the lakes.

International Institute Substainable Development