WEATHERING & SOILS

WEATHERING & SOILS

1. Weathering Earth's Surface

   • Mechanical Weathering
     • Mechanical weathering, causes rocks to crumble. Water, in either liquid or solid form, is often a key agent of mechanical weathering. For instance, liquid water can seep into cracks and crevices in rock. If temperatures drop low enough, the water will freeze.
   • Chemical Weathering
     • Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.

2. Forming Soil

   • Soil Composition
     • Soil is one of the most important elements of an ecosystem, and it contains both biotic and abiotic factors. The composition of abiotic factors is particularly important as it can impact the biotic factors, such as what kinds of plants can grow in an ecosystem
   • Soil Formation
     • Soil formation is influenced by organisms (such as plants), micro-organisms (such as bacteria or fungi), burrowing insects, animals and humans. As soil forms, plants begin to grow in it. The plants mature, die and new ones take their place. Their leaves and roots are added to the soil.
   • Soils & Organisms
     • Recall that organisms are part of Earth's biosphere. Many organisms live in soil and interact with the geosphere. Some oil organisms aid in the formation of humus, which makes soil rich in the nutrients that plants need.

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