Nearly 150 rivers and streams flow into a bay that has many species of fish, birds, and other animals. An ecologist records that the bay experiences an algal bloom every summer. The algae have a short life cycle, grow quickly in the presence of nutrients, and consume large amounts of oxygen from the bays water when they decay. Further studies confirm that runoff of excess nutrients from nearby farms is the cause for the excess algal growth. What is a likely impact of algal bloom on the bays ecosystem?

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

Nearly 150 rivers and streams flow into a bay that has many species of fish, birds, and other animals. An ecologist records that the bay experiences an algal bloom every summer. The algae have a short life cycle, grow quickly in the presence of nutrients, and consume large amounts of oxygen from the bay’s water when they decay. Further studies confirm that runoff of excess nutrients from nearby farms is the cause for the excess algal growth. What is a likely impact of algal bloom on the bay’s ecosystem?

A	It results in the deaths of fish and other aquatic organisms.
B	It decreases the number of animals that feed on algae.
C	It increases the populations of aquatic plants on the bottom of the bay.
D	It results in a shortage of space for aquatic animals to move.

Explanation:

Detailed explanation-1: -Excess nitrogen and phosphorus cause an overgrowth of algae in a short period of time, also called algae blooms.

Detailed explanation-2: -The main groups of algae found in streams are the green algae (Chlorophyta), red algae (Rhodophyta), blue-green algae (Cyanobacteria) and diatoms (Bacillariophyta). Green algae: Green algae often look like strands of green hair flowing in the current. Spirogyra is a common green alga.

Detailed explanation-3: -Cyanobacteria (blue-green algae) cause most freshwater blooms of public health concern. Cyanobacteria are a type of phytoplankton found in water and moist soil.

Detailed explanation-4: -Algal blooms form a scum over the surface of the lake, cutting off the supply of oxygen between air and the water body. These algae rob the water body of oxygen leading to the death of aquatic life. Death of both these elements further depletes the oxygen level of the freshwater body.

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GEOLOGY

EARTH SCIENCE

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