Limiting factors

1.  Limiting factors like the ability to grow or hunt food in a desert /arctic ecosystem or the amount of water in a warm desert ecosystem are limiting factors that can effect humans

2.  An algal bloom covers the ponds surface blocking sunlight.  This prevents oxygen from being created in the water and becomes a limiting factor.

3.  Abiotic limiting factors:

• Water - everything needs water.  When water is limited it reduces the carrying capacity of plants & animals.
• Living space - an ecosystem with limited living space won't have enough room to sustain large populations
• Nutrients - limited nutrients effect plant growth which will reduce the carrying capacity for plants and then everything else (or risk starvation).
• Shelter - lack of shelter puts humans and most animals in danger from elements or predators. 
• Sunlight. - Nothing would grow and it would be cold leading to starvation, and exposure.
• Weather - bad weather can destroy habitat, food and shelter.  
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