Question

Ten percent of the total available energy is stored by a consumer at each level of the food chain. If 2,533 energy units are passed on to a salmon feeding on zooplankton, how many energy units will the salmon store?

Short answer

The salmon will store 253.3 energy units.

Step-by-step solution

Understanding the Energy Transfer

In any food chain, only 10% of the energy at one trophic level is transferred to the next level. The problem states that 2,533 energy units are passed on to the salmon, so we need to calculate how much energy the salmon will store based on this transfer rate.

Calculating Stored Energy

The salmon will store 10% of the 2,533 energy units it receives. To find this, we multiply 2,533 by 0.10 (which represents 10%). This calculation is: \( 2,533 \times 0.10 = 253.3 \) energy units.

Key concepts

Trophic Levels

In an ecosystem, a food chain consists of different levels known as trophic levels. Each trophic level represents a step in the flow of energy and nutrients. Starting at the base, there are producers like plants that capture energy from the sun. They form the first trophic level by converting solar energy into chemical energy through photosynthesis.
As we move up the levels, we find primary consumers, such as herbivores, that eat the producers. Secondary consumers follow, preying on the primary consumers. At the top are the tertiary consumers that prey on the secondary ones or other consumers.
This hierarchical structure shows how energy moves from one level to the next, each time transferring only a small fraction due to various losses.

Energy Units

Within a food chain, energy flow is often quantified in terms of energy units. These units can help us understand how much energy is available for each trophic level and track its distribution through the ecosystem. Energy units might be expressed in calories, kilojoules, or other measurements that quantify energy.
The use of a standard unit helps scientists and ecologists compare and contrast the efficiency of energy transfer across different ecosystems. The units indicate not just the amount of energy present, but also allow us to calculate energy conversions, as we often see in questions requiring energy calculations, such as in the example of salmon receiving energy units.

10% Energy Transfer

The concept of 10% energy transfer refers to the efficiency with which energy is passed from one trophic level to the next. It is widely accepted that, on average, only about 10% of the energy from one level is available for the next level to store. The remaining energy is lost as heat, used in metabolic processes, or undigested food waste.
Given this understanding, when we see that 2,533 energy units reach the salmon in a food chain, we can estimate how much will be stored by knowing only 10% of this is effectively utilized. Mathematically, it means simply taking 10% of these units to determine the amount stored at that level, exemplifying the principle in energy transfer calculations.

Consumer Energy Storage

Consumer energy storage is about how organisms at various trophic levels manage and store the energy they receive. When an organism consumes energy, it uses some for metabolic functions, maintenance, and growth while storing any excess in the form of fat or other reserves.
This storage is crucial, as it provides energy during scarce times or increased activity needs. For salmon, receiving 2,533 energy units but storing only 253.3 units demonstrates the impact of energy transfer inefficiency. It highlights that only a small portion of consumed energy gets stored, affecting how much these organisms can rely on in the future.

• Metabolic activities use up energy promptly.
• Energy not used is stored for later needs.

Understanding this process helps explain why energy diminishes as it moves through trophic levels.