Krill or be Krilled: Being on the Ocean’s Food Chain

The ocean’s food chain is illustrative of the fact that all the ocean’s creatures have a purpose. Because all the ocean’s creatures have a purpose, this means that all the other creatures that depend on them for survival, as food, can survive. In the ocean’s ecosystem, the relationship between predator and prey is one that keeps life in general in the ocean in balance. In the ocean’s ecosystem, the food chain consists of predator and prey that depend on each other for survival. Everything has an impact on everything else in the ocean’s ecosystem, and it is helpful to think of this as a snowball effect. The hierarchy of life, or biological organization, is the complex biological systems and structures’ hierarchy that defines life; in underwater ecosystems, this refers to cellular-level objects like the atom, all the way up to multicellular creatures like fish and mammals and the whole ocean itself as the ecosystem.

Antarctic Underwater Ecosystems

In the Antarctic underwater ecosystem, there is a whole host of life teeming beneath the surface of that environment. In this underwater environment, the examples of underwater life can be very small, just as they can be very big. Tiny creatures in this environment include zooplankton and phytoplankton, which are organisms that drift in fresh water, seas and oceans and photosynthesizing organisms inhabiting the sunlit layer of nearly all oceans, respectively. Zooplankton gets its nutrients by way of consuming and then processing other small organisms like phytoplankton, while phytoplankton gets its nutrients by the process of photosynthesis, which explains its need to stay near the top surface of the water to absorb the sunlight.

Antarctic krill is a type of krill that is found in the Southern Ocean’s Antarctic waters. Antarctic krill feeds on various kinds of plankton, one of which is phytoplankton. Competitors of krill, with regards to feeding on plankton, include mammals such as the baleen whales. Other animals in this environment, such as penguins, seals and fish, are examples of bigger creatures that rely on krill as a food source. Various kinds of sharks are predators that in turn feed on seals, fish and penguins.

Coral Reef Underwater Ecosystems

An example of a coral reef underwater ecosystem is the Caribbean Sea area. Examples of exotic fish that call this area home are the sand shark, the lionfish, the Peacock Flounder, the Parrot Fish, the Spotted Eagle Ray and the French Angelfish. Sand sharks prey on small fish, crustaceans and squid, while other sharks have been known to prey on it. The lionfish(PDF) feeds on small fish, mollusks and invertebrates, and it is preyed on by the tiger grouper. The Peacock Flounder preys mainly on shrimp, small fish, and crabs, but crabs, bass and cod are predators of the Peacock Flounder. The Parrot Fish “preys” mainly on algae that has been extracted pieces of coral from a reef; the moray eel has been known to feed on the Parrot Fish.

The Spotted Eagle Ray feeds on crabs, shrimps, bivalves and whelks, but big sharks like the hammerhead shark prey on the Spotted Eagle Ray. The French Angelfish preys on tunicates, gorgonians, algae and sponges, while sharks prey on the French Angelfish. These fish and how they interact with one another as well as other fish in the coral reef ecosystem are a case of interdependency. Together, all these fish combine to make a whole, functioning ecosystem underwater.

Shoreline Underwater Ecosystems

One example of a shoreline underwater ecosystem is the water off of the shoreline of Cape Cod’s general vicinity. In this area, blue crabs and spider crabs abound. Spider crabs eat worms, algae and starfish, while blue crabs eat bivalves, annelids, human waste and other blue crabs. Spider crabs are preyed on by big fish, and blue crabs are preyed on by humans, sharks and fish like trout and bass. Fish that inhabit the coast off of Cape Cod include types like the sand eel and herring. The sand eel feeds on calanoid copepods and fish larvae, but birds like auks and puffins feed on them. The herring feeds on plankton, and creatures like dolphins, humans and seabirds all prey on the herring.

Other creatures that can be found in this ecosystem are gray seals, sand dollars and starfish. The gray seal feeds on fish such as herring, while sharks in the area may feed on gray seals as well as on sand dollars, even though sand dollars generally do not have that many predators to worry about. Starfish may feed on sand dollars because sand dollars are echinoderms and, thus, too slow to elude a predatory attack. All these interactions and relationships form a functioning ecosystem in this area.

All of the aforementioned, underwater areas are very different from each other. However, one thing that they do share in common is that the ecosystem and the food chain are equally significant to all areas mentioned. An ecosystem is not able to exist or function without all of its parts.