Hydrothermal vents are among the most unusual ecosystems on Earth since they are dependent on chemosynthetic organisms at the base of the food web. At mid-ocean ridges at hydrothermal vents, bacteria that use chemosyn- thesis for food energy are the base of a unique ecosystem (Figure 1.5). This ecosystem is entirely separate from the photosynthesis at the surface. Shrimp, clams, fish, and giant tube worms have been found in these extreme places. Giant tube worms found at hydrothermal vents get food from the chemosynthetic bacteria that live within them. The bacte- ria provide food; the worms provide shel- ter. A video explaining hydrothermal vents with good footage is seen here:
The open ocean is a vast area. Food either washes down from the land or is created by photosynthesizing plankton. Zooplankton and larger animals feed on the phytoplankton and on each other. Larger animals such as whales and giant groupers may live their entire lives in the open water. How do fish survive in the deepest ocean? The few species that live in the greatest depths are very specialized (Figure 1.4). Since its rare to find a meal, the fish use very little energy; they move very little, breathe slowly, have minimal bone structure and a slow metabolism. These fish are very small. To maximize the chance of getting a meal, some species may have jaws that unhinge to accept a larger fish or backward-folding teeth to keep prey from escaping. Coral reefs are among the most densely inhabited and diverse areas on the globe. In this image of Maupiti Island in the South Pacific, the remnants of the volcano are surrounded by the circular reef. An 1896 drawing of a deep sea angler fish with a bioluminescent lure to attract prey.
Corals and other animals deposit calcium carbonate to create rock reefs near the shore. Coral reefs are the rain- forests of the oceans, with a tremendous amount of species diversity (Figure 1.2). Reefs can form interesting shapes in the oceans. Remember that hot spots create volcanoes on the seafloor. If these volcanoes rise above sea level to become islands, and if they occur in tropical waters, coral reefs will form on them. Since the volcanoes are cones, the reef forms in a circle around the volcano. As the volcano comes off the hot spot, the crust cools. The volcano subsides and then begins to erode away (Figure 1.3). Eventually, all that is left is a reef island called an atoll. A lagoon is found inside the reef.
Conditions in the intertidal zone change rapidly as water covers and uncovers the region and waves pound on the rocks. A great abundance of life is found in the intertidal zone (Figure 1.1). High energy waves hit the organisms that live in this zone, so they must be adapted to pounding waves and exposure to air during low tides. Hard shells protect from waves and also protect against drying out when the animal is above water. Strong attachments keep the animals anchored to the rock. In a tide pool, as in the photo, what organisms are found where and what specific adaptations do they have to that zone? The mussels on the top left have hard shells for protection and to prevent drying because they are often not covered by water. The sea anemones in the lower right are more often submerged and have strong attachments but can close during low tides. Many young organisms get their start in estuaries and so they must be adapted to rapid shifts in salinity. Organisms in a tide pool include sea stars and sea urchins. Click image to the left or use the URL below. URL:
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the breakdown of chemicals to produce food energy.
a) hydrothermal vent b) photosynthesis --> c) chemosynthesis d) subduction
bacteria that can make food using chemicals are called chemosythetic bacteria.
--> a) true b) false
a large underwater structure created from the calcium carbonate skeletons of tiny animals is
a) an atoll. b) a lagoon. --> c) a coral reef. d) a tide pool.
a coral reef that surrounds a volcano is called a/an:
--> a) atoll b) lagoon c) pahoehoe d) aa
what is the main food source in the ocean?
a) zooplankton --> b) phytoplankton c) sea anemone d) fish
coral reefs rival rainforests in species productivity and biomass.
--> a) true b) false
the sea anemones are well adapted to their environments because they have strong attachments and can close during high tides.
a) true --> b) false
to live in the intertidal zone, organisms must be able to
a) withstand pounding waves. b) not dry out when exposed to air. c) keep from washing out to sea. --> d) all of these.
the most difficult environmental condition for an animal that lives in a tide pool is tolerating rapid shifts in salinity.
--> a) true b) false
how do fish survive in the deepest ocean?
a) they use very little energy. b) they are adapted to take advantage of any chance of a meal. c) they spend little energy building their bodies or bones. --> d) all of these.
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