In this lesson, you’ll learn what ecologists use to quantify the amount of matter in an ecological community. This often relates to the amount of energy being produced by various parts of that community.
Ecosystems ; Biomass
If you look out your window right now, you’ll most likely be able to catch a glimpse of an ecosystem, or a community of both living and nonliving elements. Ecosystems are dynamic and unique. The view out of a window in the Eastern United States will probably be quite different from the view out a window in coastal California or the Rocky Mountains or the Great Lakes region.
Despite their differences, one thing all ecosystems have in common is that they all contain matter. This matter is made up of all the plants, animals, and other living things that make up a community. When all of an ecosystem’s mass is added up, it is called the biomass of that ecosystem.Biomass refers to the overall mass of an ecosystem.
However, scientists can study more specific types of biomass too, such as plant biomass, heterotrophic biomass (organisms that eat other organisms), species biomass (the biomass for an individual species in a community), terrestrial biomass, ocean biomass, and even global biomass. Biomass may be quantified as the total amount of mass in an ecosystem or as an average amount of mass in a given area.
When trying to understand biomass, we first need to know a little more about how an ecosystem functions. Ecosystems have different energy levels called trophic levels, which are basically where different organisms exist in the food chain.Generally, as you move through the upper trophic levels, the amount of both production and biomass decreases. This is because there has to be more energy available to be consumed from the lower trophic levels. In other words, producers in an ecosystem, like plants, have to provide more energy than those that are eating them, like animals, because they are supporting those upper trophic levels.
The result is a pyramid that gets narrower as you move up through the trophic levels. This is called a productivity pyramid if you are showing the amount of productivity at each level, or a biomass pyramid if you are showing the amount of biomass at each level. Productivity and biomass are often correlated.
However, this is not always the case. In ocean and lake ecosystems, the reverse is true.
This is because in aquatic ecosystems, the algae that produce food and energy have far less biomass than that of the things eating it, like small organisms called zookplankton. This results in an inverted biomass pyramid, because even though there is more productivity at lower trophic levels, there is more biomass in things like sharks and whales, which are at the top of the food chain.
Biomass is an important piece of information that ecologists use to better understand ecosystems.
They can compare biomass to productivity and see how energy is transferred between different trophic levels.It is important to remember that productivity pyramids only indicate the amount of energy for each trophic level and can be different from biomass pyramids that indicate how much biomass is present for each trophic level. Biomass and productivity may be related, but individually they are both helpful to ecologists because they provide important information about the ecosystem being studied.