Chapter 2 Ecology 2 3 Abiotic Cycles in

Chapter 2: Ecology 2. 3 - Abiotic Cycles in the Biosphere

2. 3 – Essential Questions l. How do nutrients move through biotic and abiotic parts of an ecosystem? l. Why are nutrients important to living organisms? l. What are the 4 major biogeochemical cycles of nutrients and how are they alike?

Biogeochemical Cycles l Bio = life, geo = earth, + chemicals. l Matter – anything that has mass and takes up space. l According to the Law of Conservation of Matter, we can neither create nor destroy matter, it simply changes forms. l Nutrient – a chemical that an organism must get from the environment to sustain life and/or metabolism.

The Water Cycle l Evaporation returns water to the atmosphere. (liquid turns to gas) l Water vapor is also given off as a byproduct of respiration and plants also lose water by transpiration. l Condensation – cloud formation (gas turns to liquid) l Precipitation – rain, sleet, hail or snow falls to the earth (liquids and solids)

The Water Cycle

The Carbon-Oxygen Cycle l Photosynthesis (CO 2 → glucose + O 2) l Cellular Respiration (glucose + O 2 → CO 2) l Other activities also contribute to the release of carbon dioxide in the atmosphere: 1. Burning fossil fuels (oil, coal, etc. ) 2. volcanic activity 3. chemical processes 4. wood burning

The Carbon-Oxygen Cycle

The Nitrogen Cycle 1. Nitrogen gas (78%) in the atmosphere is converted to usable form (nitric oxides) by lightning. This falls to the earth in rain. 2. Nitrogen Fixation – bacteria change atmospheric nitrogen and nitric oxides to nitrates. 3. Plants then use nitrates make proteins. Plants also receive nitrogen from man-made fertilizers. 4. Herbivores eat plants and convert plant proteins into animal proteins. 5. Carnivores and herbivores excrete nitrogenous waste back into the soil in the form of ammonia. 6. Denitrification - bacteria then convert it to atmospheric nitrogen and so on…

The Nitrogen Cycle

The Phosphorous Cycle l Short Term Cycle – P is cycled from producer consumer decomposer. l Long Term Cycle – P is stored through sedimentation/rock formation and released when the rocks weather. l P is not found in large amounts so it can limit the growth (or be a “limiting factor”) of producers.

The Phosphorous Cycle

So, who cares? ? ? l We are made up of 70% water. l We also need oxygen to “respire. ” We couldn’t use energy without it! l Nitrogen is a key element in proteins and nucleic acids (DNA & RNA). It is also vital to life! l Phosphorous is an element needed for growth and development.