Pollution's Impact: Stress On Plants And Animals

Pollutants can put stress on plants and animals in a variety of ways. Air pollution, for example, can directly harm plants and animals through toxins in the air, or indirectly through water and soil contamination. Air pollution can also cause respiratory issues, neurological problems, skin irritations, and increased vulnerability to diseases in animals. In plants, air pollution can reduce photosynthesis and growth, damage leaf structure and function, and alter reproductive success. Additionally, ozone pollution can harm plants by damaging stomata, tiny pores on the underside of leaves that allow the plant to breathe. Water pollution and soil pollution can also have detrimental effects on plants and animals, as they are essential for their survival.

Ozone depletion

Plants are affected by ozone (O3), which causes foliar ulcers and can lead to impaired growth and even death. Ozone molecules near the ground inhibit plant respiration by obstructing the apertures in leaves where respiration takes place. This, in turn, obstructs photosynthesis, which is the process that plants use to convert sunlight to energy to live and grow. Ozone can also penetrate the stomata (plant breathing holes) and decompose plant cells directly.

The effects of ozone on individual plants can then have negative impacts on ecosystems, including changes to the specific assortment of plants present in a forest, changes to habitat quality, and changes to water and nutrient cycles. Ozone reduces crop and timber yields, resulting in economic losses. It disturbs the stability of ecosystems, leading to sensitive species dying out.

Ground-level ozone

Ozone pollution has been shown to reduce photosynthesis, which is essential for plant growth and nourishment. This reduction in photosynthesis can lead to a decline in crop yield, with nutrient-rich crops like soybeans being particularly affected. Ozone can also cause damage to leaf structure and function, including necrotic spots, premature leaf drop, yellowing, and stippling. These damages disrupt essential functions like transpiration, making plants more vulnerable to heat stress, nutrient deficiencies, and illnesses.

In addition to its direct effects on plants, ground-level ozone can also have indirect effects on animals within an ecosystem. Ozone pollution can distort the structural integrity of pollens, impacting plant reproduction. This can have cascading effects on herbivores, leading to food shortages, and subsequently affecting the predators that depend on them.

Overall, ground-level ozone is a significant pollutant that can put stress on plants and animals by disrupting their growth, reproduction, and overall health.

Excessive nitrogen

Nitrogen is an essential macronutrient for plant growth and development. However, excessive nitrogen in the atmosphere can put ecosystems under stress. Excess nitrogen acts as a fertiliser, benefiting some plants while putting others at a disadvantage. This causes natural ecosystems to become unbalanced, with long-term consequences.

Shifts in Plant and Animal Species

Excess nitrogen deposition in the form of ammonia is one of the most significant stressors on biodiversity. Biodiversity is important for animals as its loss can trigger changes in the food chain and the extinction of some species. It can also potentially raise the danger of infectious illnesses.

Rise in Pest and Disease Outbreak

Excess nitrogen causes plants to grow excessively and develop overly succulent leaves and shoots, which promotes outbreaks of certain sucking insects and mites.

Disturbance of Ecosystem Processes

Excess nitrogen can lead to disturbances in ecosystem processes such as the nutrient cycle and fire frequency. Heavy metals and other air pollutants deposited on the soil initially influence the functioning of roots. They interfere with the plant's ability to acquire soil resources, impacting plant development. At the ecological level, pollution can alter the competitive balance among species, resulting in changes in plant species composition and reduced economic yield.

Effects on Waterways

Excess nitrogen can also leach from the soil into underground water sources or enter aquatic systems as above-ground runoff. This can lead to eutrophication, where too much nitrogen enriches the water, causing excessive growth of plants and algae. This can reduce the amount of dissolved oxygen in the water, creating "dead zones" that cannot support most life forms.

Particulate matter

Smaller particles enter the stomata and interfere with the biochemistry of plant metabolism. This can prevent the plant from properly photosynthesizing. Plants that are affected by this pollution could lose the most affected leaves or fade due to the inability to photosynthesize. Leaves can also sustain chemical injuries if the deposited dust reacts with water from the environment. Alkaline dust turns toxic for plants when reacting with water.

During long-term exposure, plants are put under stress. Some fruit trees, like peaches and cherries, experience shorter flowering periods and drop fruits too soon. Their overall productivity is reduced. It is unfortunate that plants suffer harm from dust particles because they are often planted in cities to filter the particulate matter pollution from the air. Their capacity to capture dust particles helps to make city air cleaner. For example, scientists have calculated that 300 Poplar trees spread over 2.5 acres can filter out as much as 0.375 tons of dust during the summer.

Acid rain

Effects on Plants

The effects of acid rain on plants are complex and depend on various factors, including the type of plant, the acidity of the rain, and the duration of exposure. Overall, acid rain has been found to negatively impact plant growth, with aboveground and belowground parts responding differently. Here are some of the specific ways in which acid rain stresses plants:

• Reduction in nutrient availability: Acid rain can dissolve and wash away essential nutrients such as magnesium, sodium, potassium, and calcium from the soil, making them unavailable to plants.
• Damage to root and shoot systems: Acid rain can directly harm the roots and shoots of plants, impairing their ability to absorb water and nutrients.
• Leaf damage: Acid rain can cause visible damage to leaves, including yellowing, falling leaves, and injuries, which can hinder photosynthesis and stunt growth.
• Changes in soil pH: Acid rain can alter the pH of the soil, making it more acidic. This can disrupt the growth of certain plant species and affect the availability of nutrients.
• Increased vulnerability to pests and diseases: By weakening the plant's defences, acid rain can make plants more susceptible to pest infestations and diseases, further damaging their health.

Effects on Animals

While the direct effects of acid rain on animals are less well-studied, it is known that acid rain can have indirect impacts on animal life:

• Disruption of food sources: Acid rain can reduce the availability of food sources for animals by damaging plants and aquatic ecosystems. This can lead to food shortages and disrupt the balance of ecosystems.
• Water contamination: Acid rain can contaminate water sources, making them toxic to aquatic life and harmful to animals that depend on them.
• Habitat degradation: Acid rain can contribute to the degradation of habitats, particularly aquatic ecosystems, which can displace or harm the animals that rely on them.

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