1. Biosphere and Geochemical Cycles
By: Ariana.L, Kamillah .l.l , Jessica D.

8. What is the Biosphere? Earth is Wrapped in four layers:
The Lithosphere (A solid layer)
The Hydrosphere (a water layer)
The Atmosphere (The layer of air)
The Biosphere (A layer of living organisms, and their habitats)
Any area that contains living organisms, either in the Lithosphere, the hydrosphere, or the Atmosphere, it is part of the Biosphere.

9. Biogeochemical cycle: What in the world ?
There are three biogeochemical cycles; the carbon cycle, nitrogen cycle, and the phosphorus cycle, which will be presented in the next slides.
To survive and develop, living organisms need essential elements; carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. These are found everywhere on earth.
Biogeochemical cycles are the sets of processes by which these elements pass through the different environments before returning to their original status, in a never-ending loop.

10. Carbon cycle
The carbon cycle is the biochemical cycle that involves all exchange of carbon on earth.
There are steps to this cycle, here they are:
1. Photosynthesis: Plants use carbon and turns it into glucose, a complex molecule that is a source of energy.
2. Ingestion: Animals eat plants or other animals to collect glucose in them.
3. Respiration: When they breath, living beings release the carbon they digested back into the atmosphere.
4. Decomposition of waste: Decomposed by decomposers (Ex: Mushrooms), the waste of animals release the carbon that was not released by respiration.

11. Carbon Cycle Cont.
5.Forest fires: When ignition happens, leaves and trunks of plants are reverted to Carbon, their main element.
6. Shells and skeletons: Reacting with Calcium and molecules, carbon turns to calcium carbonate, and enters shells or skeletons of marine animals.
7. Carbonate rock: Placed at the bottom of the ocean floor after ocean creatures die, the carbon is put through tectonic movement, and turns to Carbonate rock as it will slowly return to the surface.
8. Volcanic eruptions: Carbonate rocks melt at contact with magma, and when volcanic eruptions happen, some carbon returns to the atmosphere when the eruptions happen.
9. Fossil Fuels: Some carbon remains buried in the ocean floor, turning over the ages into coal and other fossil fuels.

12. The Nitrogen Cycle
Nitrogen is the most abundant gas in the earth’s atmosphere, 78%. Bacteria change it into different elements, like ammonia (NH3), ammonium (NH4+), nitrites (NO2-), or nitrates (NO3-). Nitrogen also helps make proteins and DNA.
In other words, the Nitrogen Cycle is a biogeochemical cycle involving all the exchanges of nitrogen on Earth.
Humidity, PH, and human activity will alter the nitrogen cycle. To improve farming, farmers often place ammonia rich fertilizer to their fields. Afterwards, the nitrogen is washed away in wastewater of factories, or other factors. The change in nitrogen levels contained in the ground permanently affects plant growth.

13. Nitrogen Cycle (Cont.) Here are the steps in the Nitrogen cycle:
1. Nitrogen Fixation: Bacteria in water or soil takes nitrogen from the atmosphere and changes it into ammonia. Some of it reacts with hydrogen to form Ammonium.
2. Nitrification: Bacteria make ammonium react with oxygen to form Nitrites. Others turn Nitrites into Nitrates.
3. Nitrogen absorption by plants and animals: Plants gain the elements from soil and water, herbivores eat the plants to get their Nitrogen, and Carnivores or Omnivores eat meat and/or other plants.
4. Decomposition of waste: Fungi and bacteria work down animal and plant waste, returning Nitrogen to Ammonia which in turn goes to Ammonium.
5. Denitrification: Certain bacteria work on turning Nitrates back to Nitrogen, returning the gas to the atmosphere.

14. Phosphorus Cycle Definition: where phosphorus (P) travels
Phosphorus is essential to DNA and animals (shells, bones and teeth), but mostly, essential to life.
Problem: human activities create imbalance in this cycle.
Consequence: too much phosphorus = more algae. This creates eutrophication, which lessens the concentration of oxygen in the water, threatening marine life.
Fact: wind contributes to spreading Phosphorus everywhere, as far as the Sahara desert and Amazonia.

15. Phosphorus Cycle (Cont.)
Erosion: rain and water rubs the phosphorus off the rocks and it settles on the ground.
Absorption by living organisms: particles of Phosphorus enter the roots of the plants. When the animals eat the plants, it enters them as well.
Decomposition of waste: decomposed Phosphorus, found in the animal’s feces and in dead plants, integrate in the ground.
Proliferation of plankton and sedimentation: the pieces that settled in the ground sink deeper in the Earth to later reach the water. There, it promotes plankton growth (a living organism that feeds other fishes) and piles up on the bottom. After many years, the particles become rocks and the cycle starts again.

16. Quiz 1) What is the literal translation of biosphere? Life circle
2) What are 6 essentiel elements in the biosphere?
Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur
3) How much of the Atmosphere is made up of Nitrogen.
78%
4) What happens when Ammonia reacts to Hydrogen?
It forms Ammonium
5) What is the process called when bacteria turns Nitrates back to Nitrogen?
Dentrification.

17. 6) What is Phosphorus essential to?
DNA formation, animals and life.
7) What is the symbol for Phosphorus? P
8) What is Photosynthesis?
When plants turn carbon into sugar
9) What happens to leaves and trunks of plants when forest fires occur?
They turn back to carbon
10)True or false : when dead organism fall to the ocean floor, they do not turn to fossil fuels.
False: through tectonic pressure, the organism turn to fossil fuels.
11) What is the primary threat to the biosphere?
Human activities.
12) What is plankton?
A living organism that feeds other fish.

18. Thank you!