ENERGY FLOW in ECOSYSTEMS: definition, characteristics and examples

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An ecosystem is a community of organisms (such as plants, animals, and other organisms) that interact with each other within a specific geographic region or environment. All existing biodiversity within an ecosystem is organized into trophic levels based on existing food or trophic interactions, from microscopic organisms to megafauna. This structure of feeding relationships between prey and predators is determined by several factors, such as energy flows and the specific characteristics of the species.

From Ecologist Verde we propose you to learn more about the flow of energy within ecosystems, through this article in which we will talk about the definition of energy flow in ecosystems, characteristics and examples.

Definition of the flow of matter and energy in ecosystems

All living beings that inhabit an ecosystem need matter and energy to carry out their vital functions and, thus, develop their life cycles. The living beings in an ecosystem are grouped into trophic levels according to the way in which they obtain matter and energy, distinguishing the following levels:

• Producers: formed by autotrophic organisms responsible for capturing and using solar energy to transform inorganic matter into organic.
• Consumers: They are the heterotrophic organisms that feed on the producers, thus obtaining the necessary matter and energy. These are divided into primary consumers, secondary consumers and tertiary consumers, according to their predation ratio.
• Decomposers: The group of decomposing organisms includes bacteria and fungi that decompose and transform organic and inorganic remains into material that will be later used by producers.

Thus, energy flows in an ecosystem as it is captured and fixed in the form of matter by the producers and is gradually transferred to higher trophic levels, always through predatory relationships, giving rise to the flow of matter and energy from ecosystems. To further expand this topic and better understand the flows between the levels, we advise you to read this other post by Green Ecologist on What are trophic levels, what they are and examples.

How is the movement of energy within an ecosystem

The sun is the main source of energy for most ecosystems on planet Earth. But, if the sun gives the necessary energy, How is energy flow in ecosystems? This is the process:

1. Solar energy is absorbed and fixed in matter through photosynthesis by the producers, components of the base of the trophic chain; the energy fixed by the photosynthesis process is equivalent to only 1% of the total amount of solar energy that reaches the earth's surface.
2. This energy, together with matter in the form of biomass, is transferred in the following trophic levels until reaching higher levels with an efficiency of between 10-20% between one level and another, giving rise to the flow of matter and energy of the ecosystem.
3. The energy within an ecosystem dissipates as it progresses through the ecosystem, that is, it is gradually released to the environment at each trophic level in the form of heat through the process of cellular respiration. These energy losses between the different trophic levels limit the length of the trophic chains and the biomass that will reach the higher trophic levels. Thus, energy flow in an ecosystem is unidirectional, that is, it moves in a single direction from the producers to the higher trophic levels.
4. On the contrary, the matter that results from each trophic level (corpses of living beings, remains of their organisms, excrement, branches, dry leaves …) accumulates in the soil and remains at the disposal of decomposing organisms which, in turn They also release energy in the form of heat to the environment.
5. These decomposers are responsible for transforming this organic matter and returning it to the environment in the form of inorganic matter, which will be used again by autotrophic organisms to enter the food web. Therefore, a closed matter cycle and unidirectional energy flow are distinguished.

One of the characteristics of energy flow in ecosystems The most important thing is that, on the one hand, energy is neither created nor destroyed, it is only transformed and that, on the other hand, this change in shape entails a loss of energy in the form of heat.

Examples of energy flow in ecosystems

The structuring of ecosystems in trophic levels and their energy flow occurs in a similar way both in terrestrial and marine ecosystems, with the exception of some marine organisms that do not use the sun as a source of energy. To clarify the concept treated in this article, we will focus on the terrestrial system and, specifically, on the example of a forest food web. In general, the following components of the food web can be identified in a forest:

• Producers: trees, shrubs and plants.
• Primary consumers: rabbits, mice and squirrels.
• Secondary consumers: from the fox to the hawk.
• Scavengers: foxes and vultures.
• Decomposers: insects, fungi and bacteria, among other various microorganisms.

Energy flow in the forest food web

1. The water and mineral salts present in the soil are absorbed by the roots of trees and plants, to be transported to the leaves where, together with CO2 and the energy captured from the sun, organic matter is manufactured by the photosynthesis process. .
2. These plants will be consumed by primary consumers.
3. These, in turn, will be consumed by their predators, the secondary and tertiary consumers that prey at the lower levels.
4. Also, the leaves that come off the trees and plants, the branches, the fruits, etc., accumulate in the forest floor and, the decomposers, will be in charge of transforming the organic matter into inorganic nutrients. These nutrients will be absorbed again by the roots of plants and trees, starting the cycle again.

In the image below you can see another more general example on this topic, as you will see reflected a trophic network of the soil, which also serves as examples to understand energy flow in ecosystems.

Where does the energy that is lost along the food chain go?

Ecosystems lose energy in the form of heatSince living organisms cannot convert heat into other forms of energy. The heat derived from the cellular respiration process gives rise to an increase in the temperature of the organisms, a phenomenon that can be very favorable for cold-blooded organisms, helping them to be more active. Even so, and according to the physical laws of thermodynamics, heat is transmitted from colder to hotter bodies. In this way, over time, the heat produced by the organisms will be dissipated in the medium or environment. This may take some time within the ecosystem, but in the end, it will end up being lost.

If you have found it useful and you liked discovering everything about the flow of matter and energy within ecosystems, we also recommend that you take a look at this other article on How an ecosystem works.

If you want to read more articles similar to Energy flow in ecosystems: definition, characteristics and examples, we recommend that you enter our Ecosystems category.

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