Biogeochemical Cycles Marine Science

Water Cycle

The water cycle is a cycle that moves water around the earth. Beginning with evaporation the sun heats up water in the oceans or on land from lakes, rivers, ponds, ext. or sublimation which is from snow and ice, or transpiration which is water released from plants. All of these process create the water vapor in the air. When the vapor hits the lower atmosphere currents carry it upward where is is cooler. The water vapor then cools and then the gas changes into a liquid and forms water droplets in clouds, this is called condensation. Then clouds will travel around called transportation. Once the clouds grow to its capacity then the next process begins called precipitation. This is where the water falls as rain, snow, sleet, freezing rain, and hail. The water falls across the land surface, and flows in various routes. Some runs off into rivers and lakes, some can seep into the ground, though most will run off back into the ocean. Then the cycle will repeat itself.

Chemical Reactions Involved: Water throughout the water cycle is simply just H2O, there are though process where chemical reaction happen that involve the water cycle. Photosynthesis is one where plants use the the sun to get organic compounds from CO2 and H2O.

Human Impact: Some water can be taken by humans through drinking, washing, irrigating, and a large variety of other uses.

Inorganic Components: Chloride-makes water taste salty, Sulfate- causes hardness, Iron- which is needed in our diets, Fluoride- needed for proper development for our teeth and bones but can be highly toxic at high levels

Organic Components: Carbon- in sedimentary rocks, Vegetation roots- in water when they die, residues from organic matter transfer from soil to water.

the Carbon cycle

Carbon is found in all living things, also found in the ocean, rocks and air carbon is always moving. Plants use carbon dioxide and sunlight to create their own food and grow, through photosynthesis. The carbon becomes part of the plant. Plants that die are buried turn into fossil fuels made of carbon. Animals and plants also release carbon dioxide into the atmosphere as a gas, this process is called respiration. The carbon dioxide is a greenhouse gas and heats up the earth.

Chemical Reactions: Carbon Dioxide is CO2 and this is the basic compound of the cycle. Plants use CO2 and sunlight to produce O2 and C6H12O6(sugar). Animals release H20 and CO2 into the atmosphere.

CO2 is also released in other reactions. Natural reactions include: volcanic eruptions, forest fires, & volcanic vents. Synthetic reactions include: burning of fossil fuels, gasoline, & coal.

Human Impact: Humans release CO2 into the atmosphere and we burn fossil fuels, gasoline, and coal.

Inorganic Components: Rocks, animal shells, parts of the ocean and in the atmosphere.

Organic Components: All living things- plants, animals, humans, etc.

The Nitrogen Cycle

Fixation is first in the cycle that makes the nitrogen usable by plants. Bacteria changes the nitrogen into ammonium. Nitrification is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb and use to help them grow. They absorb nitrates from the soil into their roots through assimilation. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle this is called Ammonification. Extra nitrogen in the soil gets put back out into the air, and special bacteria perform this this as well through a process called denitrification

Chemical Reactions: Nitrogen in the atmosphere is N2. Other forms of nitrogen in the cycle are Nitrates (N03), Nitrites (NO2), and Ammonium (NH4).

Human Impact: We add fertilizer to our soil and causes nitrous oxide gas to be put into the atmosphere. This can cause an upset in the nitrogen cycle's balance.

Inorganic Components: Gaseous dinitrogen- N2, Ammonia (gas)- NH3, Ammonium ion- NH4+, Nitric oxide- NO, Nitrous oxide- N2O, Nitrogen dioxide- NO2, Nitrite- NO2-, Nitrate- NO3-, Urea- CO(NH2)2

Organic Components: A very diverse group of nitrogen-containing organic molecules including simple amino acids through to large complex proteins and nucleic acids in living organisms and humic compounds in soil and water. (R-NH2)

The Phosphorus Cycle

The cycle starts out with rain and weathering causing rocks to release phosphorus ions and other minerals. The phosphorus is then distributed into water and soil. Bacteria breaks down the phosphorus in the soil to a phosphate so that plants can take it in. Then the phosphate is taken up through roots on plants and then animals eat the plants and carnivores eat the herbivores. The phosphorus is then used in molecules such as DNA. When the animals or plant dies it decays and returns to the soil. Then the soil can get into waterways and rivers that lead out to oceans, which then they can incorporate into sediments over time.

Chemical Reactions: In the soil bacteria changes phosphorus ions into phosphate

Human Impact: We eat the plants and animals then we get the phosphate in our system. Farmers add phosphorus fertilizers to the soil, which then can get into the waterways.

Inorganic Components: Phosphorus in rocks, soil, sediments, and water.

Organic Components: Phosphate in plants and animals and the bacteria.

Works Cited

A Multi-Phased Journey. Earth Observatory,

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Carbon Cycle. Science Learning Hub, 10 June 2008,

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Chemical reactions. Word Press,

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The Carbon Cycle. Kid’s Crossing, Accessed 15 March


The Phosphorus Cycle. Science Learning Hub, 30 July 2015,

the-phosphorus-cycle. Accessed 15 March 2017.

The Nitrogen Cycle. Technological solutions, Inc.,

_cycle.php. Accessed 15 March 2017.

The Nitrogen Cycle. Science Learning Hub, 30 July 2013,

nitrogen-cycle. Accessed 15 March 2017.


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