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Caribbean Cruise: Examining the Movement and Quality of Organic Matter Over Time From Two Caribbean Watersheds

This article is from Issue Freshwater - Vol. 18 No. 1.

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Particulate organic matter (POM), which consists of small pieces of twigs, leaves, soil, and other items found in the water, is an important component of an ecosystem and the food web. In this study, the scientists wanted to study a certain type of POM called coarse particulate organic matter, or CPOM.  The scientists wanted to figure out how the amount and quality of CPOM changed over a period of time in the Luquillo Experimental Forest.

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Reflection Section Answer Guide

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Additional Resources for this Article:
Meet the scientists that contributed to this article:

"Thinking About Science Themes" covered in this article:
Sometimes it is useful for scientists to study something over a long period of time. The Forest Service created 81 experimental forests and ranges with this idea in mind (figure 4). The Forest Service started setting up these experimental areas in 1908. Most of the experimental areas are at least 50 years old. These areas are useful for scientists because they provide scientists with the opportunity to observe and conduct experiments in an area over a long period of time. When scientists are able to gather information over several years, they can gain a better idea of what is happening in the area. For example,think about a time in school when a student does not give his or her best effort with schoolwork. Then the student has several years in which he or she gives his or her best effort. If the student were given a choice to be evaluated over the short time period when they didn’t give their best effort or the longer time period, the student would want to be judged on the schoolwork done over the longer period of time. The longer time period would provide better information about the student. Similarly, scientists gain a deeper understanding of what is happening when they can review several years of data. Scientists are also able to identify trends in the data this way. In this article, you will learn about an experimental forest located in Puerto Rico (figure 5).
Specific "Thinking About Science" Themes:
  • The Scientific Process
  • Uses and Benefits of Science

"Thinking About Environmental Themes" covered in this article:
A watershed is the area that drains to a common waterway, such as a stream, lake, estuary, wetland, aquifer, or even the ocean (figure 6). Understanding the activities that occur within watersheds and the location of the watershed is important. The activities and location can affect the watershed’s water quality.In this research, scientists studied two watersheds in Puerto Rico. The watersheds are located in tropical forests. Tropical forests are unique because they are located near the Equator (figure 7). These forests have a high degree of biodiversity and are characterized by a lack of a winter and the occurrence of only two seasons: a wet season and a dry season. In particular, the drainage areas for the watersheds the scientists studied are located in a tabonuco (tä bə nü kō) forest. This type of forest has tall trees and very little light reaches the forest floor. The tabonuco tree (Dacryodes excelsa) dominates the tabonuco forest. The tabonuco tree can grow up to 100 feet tall (figures 8a and 8b).
Specific "Thinking About the Environment" Themes:
  • Water
  • Water Resources

NSE Standards covered in this article:
  • Abilities necessary to do scientific inquiry (A)
  • Diversity and adaptations of organisms (C)
  • Nature of science (G)
  • Populations and ecosystems (C)
  • Populations, resources and environments (F)
  • Properties and changes of properties in matter (B)
  • Risks and benefits (F)
  • Science and technology in society (F)
  • Science as a human endeavor (G)
  • Structure and function in living systems (C)
  • Understandings about science and technology (E)
  • Understandings about scientific inquiry (A)