Recycling pathways in an ecosystem play a crucial role in maintaining the balance of nutrients and energy within the ecosystem. These pathways involve the movement of essential elements, such as carbon, nitrogen, and phosphorus, through various biotic and abiotic components of the ecosystem. Key recycling pathways include the carbon cycle, nitrogen cycle, and phosphorus cycle, among others. In these cycles, organic matter is broken down by decomposers like bacteria and fungi, releasing nutrients into the soil or water. These nutrients are then taken up by plants, which are consumed by herbivores, and subsequently by carnivores, forming a food chain.

The transfer of energy in an ecosystem is referred to as energy flow rather than energy cycling because energy in ecosystems is not recycled in the same way that nutrients are. Unlike matter, which can be reused and cycled through various organisms and components of the ecosystem, energy follows a unidirectional path. It enters the ecosystem as sunlight and is converted into chemical energy through photosynthesis in plants. This energy is then transferred from one trophic level to another as organisms eat each other. However, at each transfer, some energy is lost as heat due to metabolic processes and is not available for further use. This loss of energy makes the flow of energy through an ecosystem a one-way process, resembling a flow rather than a cycle, as it doesn't return to its original source. In contrast, nutrients like carbon, nitrogen, and phosphorus can be continually recycled within the ecosystem.

Dr Gaurav H Tandon thank you for your contribution to the discussion

There are three major ways to recycle organic matter and nutrients in terrestrial ecosystems: microbial decomposition; vertebrate herbivore; and wildfires. The nutrient cycle is a system where energy and matter are transferred between living organisms and non-living parts of the environment. This occurs as animals and plants consume nutrients found in the soil, and these nutrients are then released back into the environment via death and decomposition. Nutrients consumed by plants and animals are returned to the environment after death and decomposition and the cycle continues. Soil microbes play an important role in nutrient recycling. They decompose organic matter to release nutrients. The recycling of matter is essential for the maintenance of life on Earth. Decomposing bacteria and fungi break down dead organisms. They help recycle minerals and nutrients to the environment, which can then be used by other organisms. Most decomposers are microscopic organisms, including protozoa and bacteria. Other decomposers are big enough to see without a microscope. They include fungi along with invertebrate organisms sometimes called detritivores, which include earthworms, termites, and millipedes. Chemical nutrients and energy tend to flow in the same direction for most of an ecosystem, but the main difference is that the nutrient cycle is recycled in the ecosystem while the energy flow is ultimately lost from the ecosystem to the universe at large. In the ecosystem, energy comes from the sun. The energy changes its form and flows into the following species or organic nutrient cycle. Thus, the energy is passed on to the next in an ecosystem, like entering an ecosystem as sunlight and leaves in the form of heat. Since the energy is not recycled, it is referred to as energy flow. Energy is transferred between organisms in food webs from producers to consumers. The energy is used by organisms to carry out complex tasks. The vast majority of energy that exists in food webs originates from the sun and is converted (transformed) into chemical energy by the process of photosynthesis in plants. The flow of energy in an ecosystem follows the 10% rule, meaning only 10% of the energy is transferred to the successive trophic level and the rest is lost in the atmosphere. The energy is produced by the autotrophs, as they have photosynthetic pigments to harness the sunlight into chemical energy via photosynthesis. Energy flow in an ecosystem would begin with the autotrophs that take energy from the sun. Herbivores then feed on the autotrophs and change the energy from the plant into energy that they can use. Carnivores subsequently feed on the herbivores and, finally, other carnivores prey on the carnivores.