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4 Cards in this Set
- Front
- Back
Global threats |
- climate change - poverty - desertification |
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Local threats |
- fishing - tourism - agriculture and its pollution - urbanisation - waste - deforestation (:siltation) |
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Nutrient recycling |
Nutrients are continually circulated with ecosystems. Plants take up nutrients from the soil, which are then used by the plants themselves or by the animals that consume them. When the plants or animal die, they decompose and the nutrients return to the soil. |
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Energy flows |
Ecosystems are sustained by the flow of energy through them. An ecosystems main source of energy is sunlight. Sunlight is absorbed by plants and converted into chemical energy by the process photosynthesis. Energy then passes through the ecosystem in a food chain. Each link in the chain feeds on and obtains energy from the proceeding link. Each link known as a trophic or energy level. |