The Benthic Zone The ocean can be divided in two general zones: Pelagic Zone: The open ocean Benthic Zone: The ocean floor 6 different regions of the benthic zone: Rocky Shores Sediment Covered Shores Subtidal Continental Shelf Coral Reefs Deep Ocean Floor Polar Ice

Rocky Shores Vertical Zonation: The banded pattern formed by organisms living at different levels on rocky shores. The are 3 major zones depending on how frequently it is covered with water. The upper tide zone The middle tide zone The lower tide zone

Rocky Shores The upper tide zone Mostly dry, only covered in water during high tide. Adaptations: Run and Hide Organisms often find a wet place to hide until the tide rises. Ex: Crabs

Rocky Shores The middle tide zone Is above and below the water line for equal amounts of time. Adaptations: Clam Up Organisms usually have a shell that close up to seal in some water. Ex: Mussels

Rocky Shores The lower tide zone Covered in water most of the time and only exposed to air during the lowest tides. Adaptations: Sit and Bare It Organisms can survive with some water loss. Ex: Seaweeds

Sediment Covered Shores Sediment Covered Shores: shores covered with gravel, sand, silt or clay. There are two basic types of sediment covered shores Sandy beaches Muddy Salt Marshes Wave energy determines the type of sediment covered shore.

Sediment Covered Shore Sandy Beaches can divided up into 2 zones The intertidal zone The mostly dry region of the sandy beach Adaptations: Organisms prevent dehydration by burrowing in the sediment. Infauna: Animals that live in the sediment Meiofauna: Animals that are so small that instead of burrowing they live in the spaces between the grains of sediment.

Sediment Covered Shore The subtidal zone The region of the sandy beach that is mostly covered in water. Adaptation: These organisms do not usually burrow. Why not? Epifauna: animals that live on the surface of the sediment and do not burrow.

Sediment Covered Shores Muddy Salt Marshes can be divided into 3 zones: The Lower Mud Fat: completely covered at high low, helps circulate nutrients and detritus. Cord Grass Area: cord grass provides shelter and food for many smaller marine organisms. Transition Zone: the area where the muddy salt marsh mixes with other land plants.

Sediment Covered Shores Adaptations for feeding in muddy salt marshes: Organisms in the mud flat tend to be deposit feeders and not filter feeders. Filter Feeders: have adaptations to filter food out of the water. Deposit feeders: eat food that has settled to the bottom.

Sediment Covered Shores Why are organisms in the mud flat usually deposit feeders? Finer sediments clog up the filter feeder’s nets There is a large amount of detritus that settled on the mud.

The Subtidal Continental Shelf Subtidal continental shelf: the area extending from the lowest tidal edge of rocky and sediment covered shores to the abyssal plain The subtidal continental shelf can be divided into two main regions: Soft Bottom Community: covered with sand or mud. Hard Bottom Communities: covered with rock or the hard skeletons of various marine invertebrates.

The Subtidal Continental Shelf Feeding in the Soft bottom subtidal communities Primary production in the soft bottom continental shelf is due mostly to sea grass which has roots that can anchor themselves to the soft bottom Most organisms of the soft bottom subtidal region feed on detritus through deposit or suspension feeding

The Subtidal Continental Shelf Feeding in the hard bottom subtidal communities Hard bottom subtidal communities are much more productive than soft bottom community Kelp beds are especially common in cold waters, these 100 foot long seaweeds form environments not unlike rainforests Sea urchins are the most important grazers in the hard bottom subtidal community keeping the kelp in check.

Coral Reefs Coral: a collection of small, sessile marine invertebrates. Secrete a hard limestone skeleton that builds up other many generations to for a coral reef. Most coral have zooxanthella (small photosynthetic organisms) that live inside their bodies. The zooaxanthella provide nutrients to the coral The coral provide protection to the zooanthella What type of symbiotic relationship exists?

3 Types of Coral Reefs Fringing reefs: a coral reef that develops as a narrow band close to or against a shoreline Because fringing reefs are so close to the shore they are subject to more extreme conditions such as sediment build up and exposure at low tide, both of which could kill the coral

3 Types of Coral Reefs Barrier reefs: coral reefs that develops a distance away from the shoreline and thus has a lagoon. Lagoon: the body of water between a barrier reef and the coast. Sand cay: an island formed by wave pushing sediments on top of reefs. Ex: Florida Keys

3 Types of Coral Reefs Atolls – rings of reefs that enclose a lagoon Atolls are home to the most brilliant and dramatic coral growth they are out in the middle of the ocean, and not subject to harsh conditions created by being close to land All other types of coral reefs need land and shallow water to form. It was a mystery as to how rings of coral islands can form in the middle of the ocean

3 Types of Coral Reefs Formation of atolls: First a fringing reef forms around a volcanic island A barrier reef then forms as the volcano goes extinct and starts to erode away from the reef, creating a lagoon between the reef and the island. Eventually the island sinks altogether leaving only a ring of living growing coral – an atoll

Feeding Adaptations in Coral Reefs Coral must be adapted to survive waters low in nutrients Nutrient recycling: Coral releases CO2, nitrates and phosphates. Zooxanthellae absorbs CO2, nitrates and phosphates to produce sugars and oxygen. The coral absorbs the sugar and oxygen and then releases CO2, nitrates and phosphates.

Adaptations in Coral Reefs Competition for Space With so many different organisms inhabiting such a small area, space is at a premium for corals as well as fish. Adaptations: Grow upwards and then branch out to block out light for neighboring corals. Some coral have long tentacles to sting neighbors Some corals can detach themselves and move to a new location.

Deep Ocean Floor Abyssal Plain: the large flat region of the ocean floor covered with sediment. There is virtually no light that reaches the deep ocean floor. There are no photosynthetic organisms to form the basis of the food web. All primary productivity on the deep ocean floor comes from chemosynthetic bacteria.

Deep Ocean Floor The are 3 areas of the deep ocean floor where chemosynthetic bacteria can be found: Deep sea hydrothermal vents (Black smokers): undersea hot springs associated with the mid ocean ridge. Releases hydrogen sulfide and natural gas, very hot. What is a mid ocean ridge?

Deep Ocean Floor 2. Cold seeps: areas of the deep ocean floor where hydrogen sulfide and natural gas have seeped out of the ocean floor and settled in a low spot. Similar to hydrothermal vent, but much colder 3. Dead bodies: dead whales and other organisms that have settled on the deep ocean floor

Adaptations on the Deep Ocean Floor Adaptations of the Abyssal Plain: Most organism on the abyssal plain are deposit feeders that eat dead organism that sink to the ocean floor from the surface. Ex: Sea cucumbers, Brittle Stars Predation is rare, but there is some . . . Predators usually have very large mouths Adapted to hunt in low light

Adaptations on the Deep Ocean Floor Adaptations for living near deep sea hydrothermal vents: Deep Sea Chemosynthetic Bacteria: bacteria that has adapted to take in hydrogen sulfide emitted from hydrothermal vents and covert it to food forms the basis for the deep sea food web

Adaptations on the Deep Ocean Floor Dominant animal near hydrothermal vents is a giant tube worm. Chemosynthetic bacteria live inside the giant tube worm and produce food for the worm. The tube worm collects hydrogen sulfide for the chemosynthetic bacteria. What type of symbiotic relationship exist between the tube worms and chemosynthetic bacteria?

Adaptations on the Deep Ocean Floor Adaptations for living near cold seeps Similar to hydrothermal vents Chemosynthetic bacteria form mutualistic relationships with clams and mussels. Water is much colder and more dense.

Adaptations for the Ocean Floor Adaptation for living on dead bodies Decaying organism produce hydrogen sulfide which creates communities like those seen in hydrothermal vents and cold seeps. Hydrothermal vents and cold seeps eventually “die” and stop producing hydrogen sulfide. Organisms then must find another source of hydrogen sulfide to survive. Dead bodies acts as stepping stones for organisms as they find new vents and cold seeps.

The Polar Region Two Polar regions of the Earth: Arctic Antarctic

Polar Adaptations Organism have evolved adaptations to survive the cold temperatures and obtain energy. Adaptations to Obtain Energy Sympagic Organisms: form tunnels in the ice in which they live. Bacteria and phytoplankton also live in tunnels (primary producers)

Polar Adaptations Seasonal Algal Blooms Ice melts in the summer, and phytoplankton up end up in the ocean. In the summer the ice is thinner = more sunlight reaches the water = equal algal bloom Organisms near the surface consume the phytoplankton. Dead organisms sink to the bottoms feed the benthic organisms

Polar Adaptations Adaptations to Cold Antifreeze proteins: Polar fish often survive in water that is below freezing. Why do freezing temperature of destroy cells? Antifreeze proteins prevent ice crystal from forming in the fish’s cells.

Polar Adaptations Body Shape Marine mammals have a cylindrical body shape with small appendages. Reduces the surface area to volume ratio The smaller the SA/V to longer it takes to heat up and cool down.

Polar Adaptations Blubber A thick layer fat just below the skin. Acts as insulation from the cold. Explain why blubber is better insulator than fur for diving marine organisms. Stores energy

Polar Adaptations Explain how migration can be both an adaptation form the cold and an adaptation to obtain energy.

Short Answer Questions Explain how an atoll is formed in the middle of the ocean. Use the following terms in your answer: lagoon, guyot, fringing reef, barrier reef, island. Explain how reducing the number of sea otters will be harmful to the kelp forest. Explain how the relationship between the chemosynthetic bacteria and giant tube worms are similar to the relationship between coral and zooxanthellae. How are they different. (2 similarities and 2 differences)

Short Answer Questions Explain how reducing the number of sea otters will be harmful to the kelp forest.

Short Answer Questions Explain how the relationship between the chemosynthetic bacteria and giant tube worms are similar to the relationship between coral and zooxanthellae. How are they different. (2 similarities and 2 differences)