Marine Food Webs

1. Marine Food Webs A complex ecosystem

2. Introduction to Ecosystems • Producers turn the sun’s energy into usable energy for consumers.

3. Consumers will feed on producers or other consumers for energy

4. Decomposers will feed on producers or consumers when they die and return nutrients to the system for producers to use. (bacteria, fungi)

5. Symbiotic Relationships There are three types of symbiotic relationships that can exist between two organisms: • Mutualism Both organisms benefit from the relationship - clownfish and coral or sea anemones.

6. Commensalism • One organism benefits and the other is unaffected (neither harmed or helped). Barnacles on whales or crabs

7. Parasitism • One organism (the parasite) benefits from the host, and the host is harmed. Ascaris worm in codfish Sea lice on Atlantic Salmon

8. A trophic level is the level at which a particular organism feeds in the ecosystem. Energy and biomass is lost at each level as about 90% of an organisms’ energy goes into its daily life processes and is not passed on.

10. The ocean is divided into 3 categories: • Plankton– Usually very small floating organisms, either plants or animals, which are at the mercy of the tides winds and currents. • Nekton – Strong swimming animals that live in the open ocean, and are not affected by tides or currents. • Benthos– Organisms that live on or in the ocean floor; could be plants or animal

11. Plankton • These feeble swimming plants or animals are separated into phytoplankton (plants), which are producers, or zooplankton (animals) which are first order consumers

12. Plankton • Phytoplankton are mainly diatoms which are the most important food source in the ocean, usually single celled plants (algae). They are called diatoms because of their (silica) shell symmetry designed to help them float.

13. A marine food web

14. Plankton • Dinoflagellates represent both plants and animals; they are the second most important food source in the ocean. They are often responsible for shellfish becoming toxic (“red tide”) if they have an outbreak. • The rhodophyta – red algae - can contain a toxin.

15. Zooplankton • This is the animal form of plankton. If their entire life is in this form they are called holoplankton and if they are only in this form for part of their life cycle they are called meroplankton

16. Zooplankton These animals come in different sizes and are grouped into four categories: nanoplankton – microscopic/unicellular microplankton – usually eggs and larval stage macroplankton – usually about 1mm, copepods megaplankton- mostly jellyfish.

17. Nekton • Nekton consists of all animals that are capable of swimming powerfully, mammals, reptiles, sharks, and fish. Squid are the only non-vertebrate that is a strong enough swimmer to be in this category.

18. Nekton • Although many of these animals adapted to swimming great distances, they usually remain close to one area because they have not adapted to all environmental changes in the ocean.

19. Benthos • The benthic zone consists of plants (epiflora) and animals (epifauna) on or in the bottom. Some of these organisms are the sea fan, sponges, coral, crabs mussels, and sea weed.

20. Benthos • Animals that are buried in the ocean floor like clams and worms are called infauna.

21. Benthos • The larval stage of many benthic animals is an extremely important part of the meroplankton, thus a very valuable food source for the ocean.

22. Conclusion • The marine biome is divided into four main parts: 1) Planktonic Zone – The top few metres of the ocean where plankton live. 2) Nektonic Zone – The open ocean where the inhabitants can swim to the surface or the bottom and are called nekton.

23. 3) Benthic Zone – This is the floor of the ocean where the inhabitants are usually fixed to the bottom or sessile like coral. Some (like lobster or crabs) are mobile. 4) Intertidal Zone – Organisms here are covered by water at high tide and are exposed to air during low tide. Many organisms here are adapted to living on land and under water.