Questions for ‘Here’s how some sea-loving trees ended up far from the coast’

Fish swimming around roots of red mangrove forest

Fish and other aquatic life find shelter in the underwater roots of red mangroves. This forest is in the San Pedro Mártir River on the Yucatán Peninsula. That’s in Mexico. These trees are part of a “relict ecosystem” that has existed for more than 100,000 years.

Octavio Aburto

To accompany Here’s how some sea-loving trees ended up far from the coast’  


Before Reading:

  1. As a student explores a desert, he unearths several fossils that appear to be fish skeletons. Since this desert habitat is much too dry for fish, the student is puzzled by the discovery. The fossil is estimated to be about 200,000 years old. What changes might this desert region have undergone during the last 200,000 years that might explain the presence of the fossils?
  2. A student finds a lily pad in a lake. She digs it up and replants the lily pad in a calm ocean bay, using mud from the original lake. But when she next checks on the lily pad, she finds it dead. List some differences between lake water and ocean water. Which difference do you think most likely contributed to the lily pad’s failure to survive? Briefly explain your answer.

During Reading:

  1. What did Carlos Burelo and his team find unusual about the red mangrove compared to typical mangrove trees?  
  2. What does the word “relict” mean? What is a “relict ecosystem”?
  3. Explain how sea-level changes during the last 100,000 years resulted in some mangroves becoming stuck far from today’s coast. When global temperatures become warmer, what happens to the sea level? When global temperatures become cooler, what happens to the sea level?
  4. Which part of the mangrove tree did Burelo and his team collect? What did the team do with those samples?
  5. When scientists tested other species besides mangroves, what did scientists conclude?
  6. Soil tests near the mangroves revealed “exactly what we expected” says Exequdel Ezcurra. What did those soil tests reveal? Why did Ezcurra expect such results?
  7. When it comes to sea level, what did the computer models show?

After Reading:

  1. Try this easy, overnight experiment. Cut a carrot into strips of approximately equal size. Fill up two cups with water. Label one cup “freshwater.” Label the other cup “saltwater” and add 3 tablespoons of salt to the “saltwater” cup. Add a carrot strip to each cup, and let the cups sit. After a day or two, examine each cup’s carrot strip. Describe the differences between the freshwater carrots and the saltwater carrots. Try bending the strips. Which feels more flexible? The extra flexibility indicates that the carrot has lost water, much like a wilted leaf. Based on your experiment, what effect does salt water have on a carrot’s water? Finally, apply these results to the mangrove trees. Regarding water, what problems might a saltwater plant encounter in freshwater that a freshwater plant would not?
  2. Using internet images for reference, draw a mangrove tree. Be sure to include the roots. Then search the internet for answers to the following questions: Regarding water, what unique challenge do mangroves deal with that other plants do not? Identify one adaptation that allows mangroves to handle that problem. Finally, return to your mangrove drawing, and use arrows to pinpoint where that adaptation would be located on the mangrove tree.