Biology

Question

B. Closterium

D. Spirogyra

• The chlorophyll of these algae can be hidden by a red pigment. It has been know

to turn rivers into blood.

5

Answer

The algae described are likely to be Spirogyra and Closterium, which can produce a red pigment and cause water to appear red.

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Spirogyra and Closterium are both types of green algae that can produce a red pigment called phycoerythrin. This pigment can mask the green color of chlorophyll and give the algae a reddish appearance. In large quantities, these algae can cause water to appear red, which is why they are sometimes referred to as "red tide" algae. While the red coloration can be striking, it is important to note that some species of red tide algae can produce toxins that can be harmful to humans and marine life.