© 2011 Pearson Education, Inc. CHAPTER 15 Animals of the Benthic Environment

© 2011 Pearson Education, Inc. Communities on Rocky Shores Species are –Attached to bottom –Move over seafloor (e.g., crabs, snails)

© 2011 Pearson Education, Inc. Rocky Intertidal Zonation Rocky shore: Spray and High tide zones Middle tide zone Low tide zone

© 2011 Pearson Education, Inc. Spray and Upper Tide Zone Harsh-few organisms Large Temp/Salinity Changes Both Marine and Land Predators

© 2011 Pearson Education, Inc. Middle tide zone Transition zone –More Species Diversity –More Organisms

© 2011 Pearson Education, Inc. Low tide zone Life is easy here! Stable temp/salinity Lots of Species Diversity Space limited

© 2011 Pearson Education, Inc. Sandy Beach No stable, fixed surface Burrowing provides more stable environment –Less risk of temperature extremes and drying out

© 2011 Pearson Education, Inc. Sandy Beach Burrowing Mollusks –Soft body, hard shell –Example: clams and mussels Worms (annelids) Sand Crabs

© 2011 Pearson Education, Inc. Shallow Offshore Communities Rocky Bottoms Kelp and kelp forests –Attaches to rocky bottoms –Can grow up to 0.6 meters (2 feet) per day –Provides shelter for other organisms –Rich ecosystems

© 2011 Pearson Education, Inc. Kelp Distribution

© 2011 Pearson Education, Inc. Coral Reefs Shallow water Tropical Warm, clear, shallow water Polyps – individual corals

© 2011 Pearson Education, Inc. Coral Reef Distribution

© 2011 Pearson Education, Inc. Coral Reef Zonation

© 2011 Pearson Education, Inc. Importance of Coral Reefs Largest structures created by living organisms –Great Barrier Reef, Australia, more than 1250 miles long Great diversity of species Reefs protect shorelines and freshwater supplies

© 2011 Pearson Education, Inc. Coral Reefs in Decline 30% healthy today, 41% healthy in 2000 Threats –Hurricanes –Coral bleaching –Floods

© 2011 Pearson Education, Inc. Deep-Ocean Floor Communities Hydrothermal Vents Light absent below 3300 feet Temperature usually 28°F to 37°F High pressure

© 2011 Pearson Education, Inc. Locations of Hydrothermal Vent Communities

© 2011 Pearson Education, Inc. Chemosynthesis Microscopic organisms – thrive on hydrogen sulfide from vents –Manufacture sugar, carbon dioxide, and dissolved oxygen Base of hydrothermal vent food chain

© 2011 Pearson Education, Inc. Hydrothermal Vent Species Life supported by chemosynthesis Giant tubeworms Giant clams Giant mussels Crabs

© 2011 Pearson Education, Inc. Hydrothermal Vent Communities Vents active for years or decades Animals species similar at widely separated vents Larvae drift from site to site