Image Marine trophic pyramid

TLF ID M008770

This image displays a type of diagram known as a trophic (or ecological) pyramid. This example depicts the organisms and the matter and energy flows in a typical marine ecosystem. The diagram shows six levels of organisms from primary producers through to the top carnivores, arranged in a pyramid. Also represented is the energy flow from the Sun and energy lost as heat, as well as matter and energy flows to and from decomposers.

Educational details

Educational value
  • A trophic (or food) pyramid shows the types of organisms that form a food web. Every trophic pyramid has basically the same levels, but the number and type of species in each level varies between different ecosystems.
  • In an ecosystem depicted by a trophic pyramid, the bottom level organisms - the producers - capture energy from light (by photosynthesis). In a marine environment the producers are phytoplankton, which float in the sea in enormous numbers, and algae, the seaweed. Plankton are the main producers in marine food webs, providing food for a tremendous range of marine organisms.
  • In a marine ecosystem the herbivorous consumers (or first-order consumers) are the plant-eating animals, such as molluscs and crabs, which graze on the fronds of the larger green, brown and red algae. In an ecosystem the first-level carnivorous consumers (or second-order consumers) hunt the herbivores. In a marine environment second-order consumers include: the predatory molluscs such as whelks; wading birds such as sooty oystercatchers ('Haematopus fuliginosus'), which eat molluscs and bivalves that graze on algae; and yellowfin bream ('Acanthopagrus australis'), which feed on the rocky shore at high tide, eating crabs and molluscs.
  • In a marine ecosystem the second-level carnivorous consumers (or third-order consumers) include: octopuses that hunt crabs, groper ('Achoerodus viridis') and the Port Jackson shark ('Heterodontus portusjacksoni'). They are usually fast, voracious hunters, because they have to capture a lot of prey to get the energy they need. The third-level carnivorous consumers (or fourth-order consumers) include squid that eat crustaceans, fish and cephalopods (squid, cuttlefish and nautiluses), which are first-level carnivorous consumers. The top carnivores (or fifth-order consumers) include sharks and batoids (skates and rays) that eat almost anything: fish, crustaceans, molluscs, marine mammals, and other sharks.
Year level

5; 6; 7

Learning area
  • Science

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  • Name: University of Waikato
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