Examples of Biogeochemical Cycles in Ecosystem Ecology

📚 Quick Study Guide

• 🌍 Biogeochemical cycles are pathways for elements (like carbon, nitrogen, phosphorus) to move through biotic (living) and abiotic (non-living) components of an ecosystem.
• 💧 The hydrologic cycle (water cycle) involves evaporation, condensation, precipitation, and runoff. It's driven by solar energy and gravity.
• 💨 The carbon cycle involves photosynthesis (carbon dioxide to organic compounds), respiration (organic compounds back to carbon dioxide), decomposition, and combustion. Human activities, like burning fossil fuels, significantly impact this cycle.
• 🌱 The nitrogen cycle includes nitrogen fixation (conversion of atmospheric nitrogen to ammonia), nitrification (ammonia to nitrites and nitrates), assimilation (incorporation of nitrogen into organic molecules), ammonification (conversion of organic nitrogen to ammonia), and denitrification (nitrates back to atmospheric nitrogen).
• ⛰️ The phosphorus cycle is a slow cycle involving weathering of rocks, absorption by plants, transfer through the food chain, and return to the soil through decomposition. Unlike the other cycles, it doesn't have a significant atmospheric component.
• ⚖️ Nutrient cycles are crucial for maintaining ecosystem balance and supporting life. Imbalances can lead to environmental problems like eutrophication (excessive nutrient enrichment in water bodies).

🧪 Practice Quiz

1. Which of the following is NOT a major process in the water (hydrologic) cycle?

   1. Evaporation
   2. Condensation
   3. Sublimation
   4. Transpiration

2. What is the main process by which carbon is removed from the atmosphere during the carbon cycle?

   1. Respiration
   2. Combustion
   3. Photosynthesis
   4. Decomposition

3. Which of the following processes converts atmospheric nitrogen into ammonia ($NH_3$)?

   1. Denitrification
   2. Nitrification
   3. Nitrogen Fixation
   4. Ammonification

4. Which cycle does NOT have a significant atmospheric component?

   1. Carbon Cycle
   2. Nitrogen Cycle
   3. Phosphorus Cycle
   4. Water Cycle

5. What is the process by which nitrates ($NO_3^−$) are converted back into atmospheric nitrogen ($N_2$)?

   1. Nitrification
   2. Ammonification
   3. Assimilation
   4. Denitrification

6. Which human activity has the MOST significant impact on the carbon cycle?

   1. Deforestation
   2. Reforestation
   3. Burning Fossil Fuels
   4. Crop Rotation

7. What is the term for excessive nutrient enrichment in a water body, often caused by runoff from fertilizers?

   1. Oligotrophy
   2. Eutrophication
   3. Biomagnification
   4. Leaching