Terrestrial Biomes
Applying Terrestrial Biomes
For most of the year, the Arctic tundra is completely frozen. Even during its short warming period, only a few inches of soilglossary term (opens in a new window) warm up enough to melt. Thus, much of the matter held within the permafrost has been locked up for centuries in the icy soil. For this reason, the tundra is considered a carbon sink, a reservoir that holds large amounts of carbon-containing compounds for an indefinite period of time. Scientists estimate that about 14 percent of Earth’s carbon is held within the tundra permafrost.
However, due to global temperature fluctuations, the tundra carbon sink, if it melts, could theoretically act as a carbon contributor. Some evidence suggests that patterns of increasing temperatures on Earth are extending the melting season in parts of the tundra. This means that more of the permafrost layers are melting. With each melt, the dead plant matter in the ice decays, releasing carbon into the atmosphere. And more carbon in the atmosphere holds in even more heat, causing further warming.
But the permafrost may have even more to contribute to climate change. Locked in the frozen ground are loads of methane, methane that is being released as the global temperature increases. Like carbon dioxide, methane is a greenhouse gas: a gas that serves to prevent the release of heat from the atmosphere into space. Some scientists think it will be like adding an accelerator to a cycle already out of control.
STEM and Terrestrial Biomes
Have you ever seen footage of wildfires on news programs? Wildfires are a natural part of the environmental dynamic. Biomes with wet seasons followed by long dry seasons are especially prone to wildfire because they accumulate dry vegetation that burns easily. Many plants in the grassland, chaparral and temperate forest biomes have adaptations for fire. Grasses have underground stems and buds that are unaffected by fire, while some trees depend on fire to release seeds from cones.
Why, then, are ecologists concerned about wildfires? When climate changes, the rainfall patterns also change, and this has led to drought in many parts of the world. As a result, wildfires are occurring more frequently and are burning more intensely. Wildfire season has lengthened due to warmer temperatures and drier conditions leading to early snow melt.
The issue of wildfires is a concern for a variety of professionals. Ecologists and wildlife biologists are concerned about the health of ecosystems and are studying changes in ecosystems as a result of these wildfires. Climatologists are interested in the effects of climate change on natural patterns and would like to get an idea of the patterns that lead to increased incidence of wildfires. The scientific findings could be used by land management officials to determine deployment of fire crews, to plan prescribed burns to reduce the impact of wildfires, and to improve public safety.
New technology is being employed by scientists to study the pattern and effects of wildfires. In one example, scientists are combining ground-level sampling with computer-aided three-dimensional aerial surveillance. This technology helps to determine the pattern of wildfire burns and the changes in the ecosystem as a result. Engineers with NASA launched a satellite in 2015 that measures global soil moisture. Soil moisture data can be used to predict the potential for wildfires. Atmospheric scientists with the National Center for Atmospheric Research (NCAR) have developed a model that can help predict how a fire will spread based on weather, topography, and the internal characteristics of the fire. The data from this model will be available to the firefighters on the ground. As the planet continues to get warmer and the boundaries of the biomes shift, technology aimed at predicting and mitigating wildfires may become more important to human populations.
Teacher Note
This summative assessment is intended to provide feedback on prior knowledge of the relationship between rainfall and ecosystem structure. The activity can be completed by individual students or in pairs. Teachers can assign specific regions to the groups if preferred.
