Energy moves between producers and consumers/decomposers, and the nutrients from soil or air (minerals, etc.) move into the producers and the consumers. All are linked together, regardless of the biome, but food levels have tropic levels and positions. This starts with a basal species that feeds on no other living creature, then moves up to where something consumes something else in order to survive: (Yellow line is transfer of energy; red arrow is transfer of nutrients).

Simple Biome Food Web of an Arctic shore area

1. Within our example, the primary producers are the zooplankton and phytoplankton which are consumed in part by every other animal in the food web except the top carnivore. The top consumers are the carnivores (polar bears, orca) that subsist on the top mammal and bird consumers (seals, walruses, penguins)....

This level also consumes the fish level, but also, at times the crustacean (D) levels.
2. The higher up the food web the more expenditure of energy to maintain health, but the fewer amounts of food (energy necessary). For instance, it takes sun energy to grow kelp and phytoplankton per unit. Then, when fish eat the plants and plankton, they are consuming thousands of energy units to grow their bodies, and it might take only 3-4 to feed a carnivore daily, and only 1 seal or penguin/walrus to feed a polar bear weekly. But at each level upward, more energy was needed for that organism to survive.

3. A very real example might be changes in water chemistry and/or water temperature in the biome which would not allow the planktons to exist. Without this, the cycle of fish would not live, nor would other large predators of this food