Problem 12 - Biology Today and Tomorrow with Physiology

Question

Addition of _______ to water encourages algal blooms. a. carbon dioxide b. phosphate ions c. salt d. bicarbonate ions

Step-by-Step Solution

Answer

The addition of phosphate ions to water encourages algal blooms.

Step 1: Understanding Algal Blooms

Algal blooms are rapid increases of algae in water systems, which can be harmful. They often occur when there are excess nutrients in the water that algae feed on, promoting their growth.

Step 2: Identifying Nutrients Contributing to Algal Growth

Nutrients that typically contribute to algal blooms include nitrogen and phosphorus compounds, as they are essential nutrients for algae.

Step 3: Evaluating the Options

Let's analyze each option: - (a) Carbon dioxide: While CO2 is necessary for photosynthesis, it is not the primary cause of algal blooms. - (b) Phosphate ions: These are a form of phosphorus, a key nutrient that often causes algal blooms when in excess. - (c) Salt: Does not contribute to algal growth and can actually inhibit it. - (d) Bicarbonate ions: Do not directly contribute to algal blooms.

Step 4: Selecting the Correct Option

Based on the explanation, phosphate ions are the nutrients that when added to water, are most likely to encourage algal blooms.

Key Concepts

Phosphate Ions

Phosphate ions play a vital role in the growth of plants, including algae, which are tiny aquatic plants. When phosphate ions end up in water systems, they become a food source for algae. This can lead to rapid and uncontrolled algal growth. Phosphates can enter water bodies through several human activities:

• Use of fertilizers: Phosphates are commonly found in fertilizers used in agriculture, and when it rains, these phosphates can be washed into nearby rivers or lakes.
• Detergents: Some detergents contain phosphates, and when wastewater containing these detergents enters water systems, it can contribute to phosphate levels.
• Sewage: Untreated or poorly treated sewage often contains phosphates which can elevate levels in water bodies.

When phosphates are present in high amounts, they lead to algal blooms, which can have detrimental effects on aquatic life and water quality. This makes managing phosphate levels crucial to maintaining healthy water ecosystems.

Nutrient Pollution

Nutrient pollution occurs when too many nutrients, mainly nitrogen and phosphorus, enter water systems. This can lead to several environmental problems. Normally, nutrients are necessary for plant growth, but too much of them can cause issues. When water bodies receive excessive nutrients, particularly from human activities, it can result in:

• Algal blooms: These are the most common and visible effects of nutrient pollution. They can turn water green and have a harmful impact on aquatic life.
• Oxygen depletion: As algae die and decompose, they consume oxygen in the water, which can lead to "dead zones," areas where most aquatic life cannot survive.
• Water quality issues: Nutrient pollution can make water unsafe for swimming and drinking.

Controlling nutrient inputs from agriculture, industry, and residential areas is essential to reduce nutrient pollution and protect water resources.

Water Ecosystems

Water ecosystems include all living organisms and non-living elements in a water environment, such as lakes, rivers, and oceans. They are complex and delicate systems that support diverse forms of life. The health of these ecosystems is crucial for sustaining biodiversity. However, they are susceptible to disturbances like nutrient pollution. Nutrient overload, particularly phosphates and nitrates, can severely impact water ecosystems by causing changes such as:

• Algal blooms: As discussed, these disrupt the balance of the ecosystem by blocking sunlight and depleting oxygen.
• Loss of biodiversity: Species that cannot survive in altered conditions may decline or disappear, leading to less variety of life forms.
• Water contamination: Toxic substances produced by some algal blooms can poison fish, wildlife, pets, and even humans.

To safeguard water ecosystems, it’s important to adopt measures that limit nutrient pollution, promote sustainable agricultural practices, and improve wastewater treatment processes.