How Can a Tiny Krill Affect the Entire Marine Biome?

This small creature affects all kinds of species in the world

Krill – tiny but vital. Image provided by Popular Journal

One of the tiniest creatures in the marine biome has a colossal impact on every single species in the ocean. Without krill, every species will see its inevitable demise, starting from small fishes to the largest whales: they will all collapse in the food chain. Now - why can such a tiny creature cause this gigantic problem?

While krill may look unhelpful, they actually do a lot for the ecosystem. Firstly, whales depend entirely on krill for consumption. Whales are designed to eat lots of krill at the same time, so if krill disappear, whales will too. As krill are energy-rich and can be found nearly anywhere in the sea, whales do not have to expend much energy in hunting for food. Whales, which highly depend on krill, impact humans as well. Whale feces are commonly used in agriculture for composition and fertilizing, so the disappearance of these small creatures could even impact human society.

Secondly, it will also impact lots of fish. Since krill are at the bottom of the food chain (the primary consumers), many consumers depend on them. The secondary consumers, such as squid, sardines, salmon, and seabirds depend hugely on krill too. Sardines and salmon are highly eaten by tertiary consumers. With the extinction of krill, sardines and salmon could not be consumed by predators. Tertiary consumers such as sharks and humans depend on seafood. Sharks usually prey on salmon and fishes that are medium-sized. Krill have a huge impact on medium-sized fish since they tend to eat krill. If krill disappear, the impact would cascade upward, affecting not only fish but also the predators further up the chain, ultimately disrupting the entire marine ecosystem.

Third, krill can impact the land as well. Seabirds highly depend on fish and krill. Without krill, fish will die, leading to sea birds dying as well. If sea birds die, land predators such as raccoons, foxes, and skunks, which rely on seabirds as a food source, will be in significant trouble. While these predators have alternative food sources, the loss of seabirds would still cause significant damage to their main sources of food.

Although all living creatures are keystone species, where if one breaks, the whole food chain will break, krill can be argued to be the most important keystone species to the marine biome. Krill have a huge energy role for the countless number of consumers, and not only give importance to the marine ecosystem but also impact the land. There is still much more to discover and learn about these tiny but crucial organisms.