2011 Pearson Education, Inc. CHAPTER 15 Animals of the Benthic
Environment Slide 2 2011 Pearson Education, Inc. Chapter Overview
Benthic communities include a variety of habitats. Corals need
specific environmental conditions. Hydrothermal vents support
diverse communities that rely on chemosynthesis. Slide 3 2011
Pearson Education, Inc. Distribution of Benthic Organisms Slide 4
2011 Pearson Education, Inc. Communities on Rocky Shores Epifauna
Attached to substrate (e.g., marine algae) Move over seafloor
(e.g., crabs, snails) Moderate diversity of species Greatest animal
diversity at tropical latitudes Greatest algae diversity at
mid-latitudes Slide 5 2011 Pearson Education, Inc. Intertidal
Zonation Rocky shore: Spray zone above spring tide zone Intertidal
zone High tide zone Middle tide zone Low tide zone Slide 6 Slide 7
2011 Pearson Education, Inc. Sandy Beach Organisms and Adaptations
Burrowing animals No stable, fixed surface Burrowing provides more
stable environment Less risk of temperature extremes and drying out
Slide 8 2011 Pearson Education, Inc. Shallow Offshore Ocean Floor
Communities Rocky bottoms (subtidal) Kelp and kelp forests Attaches
to rocky bottoms Can grow up to 0.6 meters (2 feet) per day
Productive ecosystems Provides shelter for other organisms Slide 9
2011 Pearson Education, Inc. Kelp Distribution Slide 10 Slide 11
2011 Pearson Education, Inc. Rocky Bottom Shallow Offshore Ocean
Floor Communities Lobsters Large, spiny antennae Live in water
deeper than 20 meters (65 feet) Scavengers Also feed on live
animals Slide 12 2011 Pearson Education, Inc. Rocky Bottom Shallow
Offshore Ocean Floor Communities Oysters Sessile bivalve mollusks
Thick shell Start life as plankton Slide 13 2011 Pearson Education,
Inc. Coral Reefs Reefs shallow water communities restricted to
tropics Polyps individual corals Slide 14 Slide 15 - Sponges and
Cnidarians Cnidarians Cnidarians have two basic body plans, the
vase-shaped polyp and the bowl-shaped medusa. Slide 16 Slide 17
Slide 18 2011 Pearson Education, Inc. Coral Reef Distribution Slide
19 Photosynthesis They get most of their nutrients from symbiotic
unicellular algae called zooxanthellae. What is needed for this to
happen? Slide 20 2011 Pearson Education, Inc. Conditions for Coral
Reef Development Warm (but not hot) seawater Sunlight (for
symbiotic algae) Strong waves or currents Clear seawater Normal
salinity Hard substrate Slide 21 2011 Pearson Education, Inc. Coral
Reef Zonation Slide 22 2011 Pearson Education, Inc. Importance of
Coral Reefs Largest structures created by living organisms Great
Barrier Reef, Australia, more than 2000 km (1250 miles) long Great
diversity of species Important tourist locales Fisheries Reefs
protect shorelines Slide 23 2011 Pearson Education, Inc. Humans and
Coral Reefs Fishing, tourist collecting, and sediment influx due to
shore development harm coral reefs. Sewage discharge and
agricultural fertilizers increase nutrients in reef waters.
Hermatypic corals thrive at low nutrient levels Phytoplankton
overwhelm at high nutrient levels Bioerosion of coral reef by
algae-eating organisms Slide 24 2011 Pearson Education, Inc. Crown
of Thorns Phenomenon Sea star eats coral polyps Outbreaks (greatly
increased numbers) decimate reef Slide 25 Outbreaks are due to
human influences. * Pollution/Nutrients * Lower Salinity Are these
related? *Overfishing Slide 26 Corals Cannot handle any change to
water temperature, pH, light intensity. Global warming = Water Temp
Global warming = CO2 = acidic oceans Pollution = Turbidity ALL
cause STRESS to Coral Very SLOW growth rates (1 inch per year for
fast growers to 2 inches in 100 years for slow growers) Slide 27
Coral Reefs are VERY Productive areas Slide 28 2011 Pearson
Education, Inc. Coral Reefs in Decline 30% healthy today, 41%
healthy in 2000 One third of corals high risk of extinction Humans
greatest threat Other threats Hurricanes Global warming Coral
bleaching Floods Tsunami Slide 29 Coral Stress First: Dump their
zooxanthellae temporarily (Coral Bleaching) If stress is short term
(weeks) then afterwards, zooxanthellae will grow back and all is
OK. If stress continues, Coral DIES. Slide 30 Slide 31 2011 Pearson
Education, Inc. Deep-Ocean Floor Communities Less known about than
shallower water communities Expensive to explore the deep Limited
oxygen Robotic technology for exploration
