Benthic Communities

living along the

bottom of the ocean

Benthic Communities

living along the

bottom of the ocean

Benthic Communities

• Rocky Intertidal Zones

• Coral Reefs

Rocky Intertidal Zones

Rocky Intertidal ZonesHard places to live

• Drying out during low tide– Close shells, move to moist areas

• Wave Shock– Have holdfasts, cement, tube feet

• Lack of space to hold on– competition

• Rapid changes in temperature & salinity– Close shells or be able to withstand it

Table 15.1

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 18-21oC (64-70oF)

Fig. 14-12, p. 294

Coral Reefs

• Reefs support a large diversity of other organisms– Home to 25% of the world’s marine species

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 or wrasse, zooxanthellae

– commensalism (+0)• pea crabs, remoras & shark, whale barnacles

– parasitism (+-)• isopods, roundworms, etc.

Figure 14.15b

Figure 10 p.221

Figure 14.15a

Figure 14.15c