Abiotic factors are the non-living, physical and chemical, conditions of an ecosystem. Each species survives only within a certain range of each factor, so abiotic factors decide where organisms can live.• Light intensity: needed for photosynthesis, so it controls plant growth. Plants on a woodland floor have adaptations such as large leaves, or grow and flower early in spring before the canopy closes.
• Temperature: affects enzyme activity, so it affects the rate of photosynthesis, respiration and growth. It is especially important for plants and ectothermic animals.
• Water availability: needed for photosynthesis, transport and support. Where water is scarce, only drought-adapted plants (xerophytes) survive.
• Oxygen availability: aquatic organisms depend on dissolved oxygen, which is lower in warm or still water. Waterlogged soils lack oxygen for roots.
• Soil (edaphic) factors: pH, mineral content, texture and drainage decide which plants can grow.
• pH of water or soil affects enzymes and the availability of mineral ions.
• Salinity, wind and humidity also matter, for example in exposed coastal areas.Example: in a rock pool, as the tide goes out the water warms up in the sun, loses dissolved oxygen, and becomes saltier as water evaporates. Only organisms that can tolerate these changing abiotic conditions survive there.Abiotic factors can often be measured with simple equipment, such as a light meter, thermometer, pH probe or oxygen probe.
• Temperature: affects enzyme activity, so it affects the rate of photosynthesis, respiration and growth. It is especially important for plants and ectothermic animals.
• Water availability: needed for photosynthesis, transport and support. Where water is scarce, only drought-adapted plants (xerophytes) survive.
• Oxygen availability: aquatic organisms depend on dissolved oxygen, which is lower in warm or still water. Waterlogged soils lack oxygen for roots.
• Soil (edaphic) factors: pH, mineral content, texture and drainage decide which plants can grow.
• pH of water or soil affects enzymes and the availability of mineral ions.
• Salinity, wind and humidity also matter, for example in exposed coastal areas.Example: in a rock pool, as the tide goes out the water warms up in the sun, loses dissolved oxygen, and becomes saltier as water evaporates. Only organisms that can tolerate these changing abiotic conditions survive there.Abiotic factors can often be measured with simple equipment, such as a light meter, thermometer, pH probe or oxygen probe.