Q12TYU - Campbell Biology

Question

Watermelon snow” in Antarctica is caused by a species of photosynthetic green algae that thrives in subzero temperatures (Chlamydomonas nivalis). These algae are also found in highaltitude year-round snowfields. In both locations, UV light levels tend to be high. Based on what you learned in this chapter, propose an explanation for why this photosynthetic alga appears reddish-pink.

Step-by-Step Solution

Answer

The algae appear reddish pink because of the pigment protecting these organisms from UV rays at high altitudes.

Step 1: Chlamydomonas nivalis

Chlamydomonas nivalis is a red color alga found in the alps and polar regions of the world. These algae can survive in conditions of low temperature, intense sunlight, and limited nutrients. The algae are also known as cold-loving green algae.

Step 2: Watermelon snow

Watermelon snow is a phenomenon that is caused by the algae Chlamydomonas nivalis. The presence of these algae turns the snow pink or scarlet. The snow also smells sweet like watermelon and is thus called watermelon snow. 

 

The Sierra Nevada mountains of California are often covered with watermelon snow.

 

Step 3: Presence of pigment in the cells of the algae

The algae Chlamydomonas nivalis contains a pigment called carotenoid. These pigments protect the algae from heat and UV radiation. They reflect the UV rays, and thus, they appear reddish-pink to humans.