How does energy flow differ in aquatic and terrestrial ecosystems?

Energy flow in aquatic and terrestrial ecosystems differs mainly in the types of organisms involved and the efficiency of energy transfer.

In both aquatic and terrestrial ecosystems, energy flows from the sun to producers, then to consumers and finally to decomposers. However, the types of organisms that play these roles differ between the two ecosystems. In terrestrial ecosystems, plants are the primary producers, capturing sunlight through photosynthesis to create energy-rich compounds. Herbivores, such as rabbits or deer, consume these plants and are in turn eaten by carnivores, such as wolves or lions. Decomposers, such as fungi and bacteria, break down dead organisms and return nutrients to the soil.

In contrast, in aquatic ecosystems, the primary producers are often microscopic phytoplankton, which float in the water column and photosynthesise. These are eaten by small aquatic animals, or zooplankton, which are then consumed by larger aquatic animals. Decomposers in aquatic ecosystems include bacteria and other microorganisms that break down dead material and recycle nutrients back into the water.

The efficiency of energy transfer also differs between aquatic and terrestrial ecosystems. In general, energy transfer is less efficient in terrestrial ecosystems because plants have a lower net primary productivity (NPP) due to factors such as a shorter growing season and less available light and nutrients. This means that less energy is available for herbivores and, consequently, for higher trophic levels. In contrast, aquatic ecosystems often have a higher NPP because phytoplankton can reproduce quickly and take advantage of abundant light and nutrients in the water, leading to a more efficient energy transfer.

However, it's important to note that these are general trends and there can be significant variation within both aquatic and terrestrial ecosystems, depending on factors such as climate, nutrient availability and the specific organisms present.