Benthic Communities living along the bottom of the ocean

The Producers Seaweeds –multicellular algae or macroalgae Flowering Plants

Seaweeds Have blades, stipes, holdfasts, gas bladders Entire body is called the thallus Classified based on pigments

Fig. 14-2b, p. 285

Seaweeds Green Algae- Chlorophyta –Only chlorophyll, No accessory pigments –Ex: Sea lettuce

Seaweeds Brown Algae- Phaeophyta –Chlorophyll & Brown/Yellow accessory pigments –Ex: rockweed, kelp

Seaweeds Red Algae - Rhodophyta –Chlorophyll & Reddish accessory pigments –Most numerous –Can live in deeper waters

Flowering Plants Seagrasses –Eel grass (Zostera) –Form large meadows –Support large community

Flowering Plants Mangroves –Trees, never completely submerge –Arching prop roots Support the trees Protect other species Slow currents

Fig. 14-5, p. 287

Phylum Cnidaria Jellyfish (pelagic), sea anemones, corals

Phylum Cnidaria

Phylum Cnidaria - CORAL

Coral Reefs Corals –Are animals (Cnidarians) –Small (ant-sized) polyps live in large colonies –Hermatypic corals secret a calcium carbonate skeleton…the reef

Coral Reefs Zooxanthellae –Dinoflagellate that lives within the coral polyp –A mutualism –Algae provide food, speeds up calcium carbonate deposition & get nutrients in return

Coral Reefs Hermatypic Coral’s ideal habitat is 5-10 m (16-33 ft) depth & temperatures warmer than 21 o C (70 o F)

Fig , p. 294

Symbiosis the co-occurrence of two species in which the life of one is closely tied with the life of another

Symbiosis Three types –mutualism (++) Anemone fish, cleaner shrimp, zooxanthellae –commensalism (+0) Pea crabs, remoras & shark, whale barnacles –parasitism (+-) Roundworms, etc.

Figure 10 p.221

Other Benthic Animals: Phylum Mollusca 3 Main groups –Gastropods (snails & slugs) & Bivalves (oysters, clams, mussels) are benthic –Cephalopods: octopus = benthic, squid = pelagic

Phylum Mollusca

Fig. 14-7, p. 289

Phylum Mollusca

Phylum Arthropoda - Crustaceans Crabs, lobster, shrimp, barnacles

Fig. 14-CO, p. 282

Phylum Arthropoda Class Crustacea

Phylum Arthropoda - Crustaceans Most successful animal group Jointed appendages Exoskeleton - chitin –Must molt

Phylum Echinodermata Sea stars, sand dollars, brittle stars, sea urchins

Fig. 14-4, p. 287

Phylum Echinodermata

Phylum Echinodermata Radially symmetrical as adults Water vascular system –Serve in feeding and locomotion –Tube feet

Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Species Interact in Ecosystems