APES Cycles Quiz

Nitrogen Cycle

• Nitrogen fixation - Nitrogen gas in the atmosphere is converted into forms of nitrogen that producers can absorb. This can happen in ways such as bacteria converting nitrogen into ammonia or ammonium which are forms that producers can use.

• Nitrification converts ammonium in the soil into nitrite and then nitrate. These conversions are completed by nitrifying bacteria/

• Once producers take in nitrate, they incorporate it into their body using the process of assimilation, becoming DNA or protein.

• In mineralization, decomposers like fungi and bacteria break down organic matter from dead bodies and waste products converting organic compounds back into inorganic compounds. This process is sometimes called ammonification because the product may be inorganic ammonium.

• Denitrification converts nitrate into nitrogen gas which is released back into the atmosphere. Bacteria does denitrification.

Hydrological Cycle(water)

• Light from the sun warms up bodies of water which causes the evaporation of water from liquid to gas state.

• Transpiration is when plants release water from their leaves into the atmosphere.

• The water vapor that enters the atmosphere cools and forms clouds through a process called condensation and it then produces precipitation in the form of rain, snow, and hail.

• The mechanisms of water returning to the atmosphere is called evapotranspiration.

• When water falls on land, it can take three routes. First, it can return to the atmosphere through evapotranspiration. Second, the water can be absorbed by the soil and become groundwater during infiltration, in which it will reach the water table, which is a water-saturated zone of soil and rock known as an aquifer. Third, water can move as runoff across the land surface into streams and rivers, eventually reaching the ocean.

• As water in the ocean evaporates, the cycle begins again.

Phosphorus Cycle

• The main reservoir of phosphorus is rock and soil.

• During assimilation, producers on land an in water take up inorganic phosphate and assimilate them into their tissues as organic phosphorus. The waste products and dead bodies of these organics are decomposed by fungi and bacteria. 

• Since phosphorus is not very soluble in water, much of it precipitates out to form sediments in the ocean. Over time, geological uplift can lift these ocean layers up to become mountains. The phosphate containing rocks experience weathering by natural forces(for example rain) which brings phosphorus to aquatic and terrestrial habitats. Humans use phosphate mining to make phosphorus available for fertilizer, detergents, and other uses.

• The leaching of detergents and fertilizers occurs when dissolves molecules are transported through the soil via groundwater, which contributes to the amount of phosphates in the soil.

• Phosphorus is a limiting nutrient in many aquatic systems because even through water may carry phosphorus from the soil to aquatic systems by runoff, since phosphorus does not dissolve in water there is very little phosphorus naturally available in streams, rivers, and lakes. 

• Algal blooms can be harmful and are the result of more phosphorus being added to soils and water systems than what naturally occurs which is due to leaching from human fertilizers and detergents. This can allow an excess of producers to grow.

Carbon Cycle

The carbon cycle has slow and fast moving parts. The fast moving part involves processes that involve living organisms and the slow moving parts involve carbon that is held in rocks, soils, or fossil fuels. When producers undergo photosynthesis, they take in carbon into their tissues. Some of this carbon is returned as carbon dioxide when organisms do cellular respiration. 

• Exchange is the process in which carbon can be exchanged directly between the ocean and the atmosphere. Carbon released from the ocean into the atmosphere is about the same rate that atmospheric carbon dioxide diffuses into the water. The dissolved carbon dioxide can be taken up by producers, released into the water through respiration, or combined with calcium ions to form limestone in a process called sedimentation.

• Carbon can be combined with calcium ions to form limestone in a process called sedimentation. Sedimentation occurs very slowly. 

• Humans have performed extraction, which is the digging for fossil fuels such as coal, oil, and natural gas which humans rely on for energy. Once extracted, humans use combustion to burn these fossil fuels to release carbon into the atmosphere as carbon dioxide.