Chapter 18

1. Chapter 18 Life in the Ocean’s Depths These slides are the ones used during review plus slides students developed for their presentations © 2006 Thomson-Brooks Cole

2. Key Concepts • Several thousand species have adaptations that allow them to survive in the deep-sea environment. • The lack of light has had the most impact in shaping the organisms of the deep sea. • Many deep-sea animals exhibit bioluminescence, which helps them find mates and prey in their dark environment. © 2006 Thomson-Brooks Cole

3. Key Concepts • Deep-sea fishes display a variety of adaptations such as sharp teeth, large mouths, and huge stomachs that help them survive in a habitat with limited food. • The environmental conditions of the deep sea have been relatively stable for more than 100 million years, and as a result, several organisms have changed very little from when they first evolved. © 2006 Thomson-Brooks Cole

4. Key Concepts • Benthic communities consist of sparse populations that survive on the minimal food available in their environment. • Thriving marine communities that depend on chemosynthetic bacteria for primary production exist on the ocean floor around hydrothermal vents. © 2006 Thomson-Brooks Cole

5. Survival in the Deep Sea • The deep sea is an inhospitable place • frigid temperatures throughout the year • tremendous pressure • total darkness • Conditions have remained stable over many years • Some creatures have evolved to survive in this harsh environment © 2006 Thomson-Brooks Cole

6. Survival in the Deep Sea • Adaptations to pressure • fluid pressure within the animal’s tissues matches the pressure of the seawater • Adaptations to cold • nearly all have body temperatures close to that of the surrounding water • slow metabolism – slow movement, growth; less reproduction, longer life • high density of cold water matches that of animal’s bodies – they don’t sink © 2006 Thomson-Brooks Cole

7. Life in the Dark • Color in deep-sea organisms • countershading employed in the disphotic zone—region of dim light (twilight) • photophores (light-producing organs) may be used to make the ventral surface lighter • many species are bright red or orange • appear black or gray in dim light • many are bioluminescent © 2006 Thomson-Brooks Cole

8. Life in the Dark • Roles of bioluminescence • how bioluminescence works • a protein called luciferin is combined with oxygen in the presence of an enzyme called luciferase and adenosine triphosphate (ATP) • chemical energy of ATP converted to light • camouflage • bioluminescence matches the intensity of sunlight, and thus contributes to countershading, in the twilight zone © 2006 Thomson-Brooks Cole

9. Life in the Dark • Roles of bioluminescence (continued) • mating and species recognition • identifies the sex of an individual • allows for identification of species • attracting prey • anglerfish and stomiatoids attract prey with bioluminescent lures • light may be used to locate prey in the dark • defense • deepwater squid and shrimp release clouds of bioluminescent materials to confuse predators © 2006 Thomson-Brooks Cole

10. Life in the Dark • Seeing in the dark • many deep-sea fishes have tubular eyes containing 2 retinas instead of 1 • 1 retina views distant objects, while the other views closer objects © 2006 Thomson-Brooks Cole

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12. Life in the Dark • Finding mates in the dark • male becomes a parasite on the female in some species of anglerfish • Finding food in the dark • benthic organisms and scavengers eat detritus which drifts down from above • many small fishes and invertebrates migrate upward at night to feed • adaptations include large mouths and expandable stomachs © 2006 Thomson-Brooks Cole

13. Life in the Dark • Finding food in the dark (continued) • some can eat prey larger than themselves • stomiatoids have barbels (fleshy projections) that may be used as lures, probes or for species recognition • anglerfishes have a spine used as a fishing pole, tipped with a luminous lure © 2006 Thomson-Brooks Cole

14. Giants of the Deep • Giant squids • New species of deepwater squid • large, unnamed species discovered 1988 • have longer arms than other squid, bent downward at sharp angles • exhibit different behaviors • hide in their ink clouds instead of fleeing • pairs have been observed attached, towing each other through the water © 2006 Thomson-Brooks Cole

16. Giant Squid: • Is the largest of the invertebrates • are weak swimmers, probably cannot capture active prey • still use jet propulsion to swim • seen in waters between 1930 – 4709 meters deep • Hide in ink cloud rather than swimming away http://www.bing.com/videos/watch/?q=giant+squid&vid=8E5AABFB805D0946A6898E5AABFB805D0946A689&docid=408227480290&FROM=LKVR5&GT1=LKVR5&FORM=LKVR9

17. Relicts from the Deep • Spirula • small molluscs resembling squid and octopuses with spiral-shaped internal shells • similar to belemnites common in the sea 100-50 million years ago • Vampire squid • dark-colored, webbing between its arms • thought to be descendents of an intermediate organism between squids and octopuses © 2006 Thomson-Brooks Cole

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19. Relicts from the Deep • Coelacanth • fish with large, thick scales and fleshy bundles between its body and fins • thought to be extinct for 70 million years until 1 was caught alive in 1938 • Neopilina • limpet-like mollusc • thought to be extinct for 350 million years until 1 was found in 1952 © 2006 Thomson-Brooks Cole

20. Life on the Sea Bottom • Benthic communities • sources of food for benthic organisms • organic matter rains down from surface waters and accumulates on the ocean floor • a large carcass will occasionally drift down • food chains • bacteria are consumed by meiofauna (e.g. foraminiferans and nematodes) • infauna (e.g. worms, bivalves) eat meiofauna • deposit feeders and suspension feeders • predators include fishes, squids, sea stars © 2006 Thomson-Brooks Cole

21. Life on the Sea Bottom • Benthic communities (communities) • diversity of benthic organisms of the deep • low numbers, but high diversity • ineffective dispersion of young may lead to isolation, which contributes to speciation • stable conditions may prevent extinction of species, so species proliferate © 2006 Thomson-Brooks Cole

22. Life on the Sea Bottom • Vent communities • self-contained communities that are some of the most productive in the sea • formation of vents • vents form at spreading centers • seawater seeps down to where it contacts magma • water is superheated, and loses some minerals while it picks up others, such as sulfur, iron, copper and zinc © 2006 Thomson-Brooks Cole

23. Life on the Sea Bottom • Vent communities (continued) • types of vents • white smokers—produce a stream of milky fluid rich in zinc sulfide; water temperature is normally less than 300o C • black smokers—narrow chimneys that emit a clear water with temperatures of 300o to 450o C that is rich in copper sulfides (which precipitate with contact with cold seawater, to produce the black color) © 2006 Thomson-Brooks Cole

24. Life on the Sea Bottom • Vent communities (continued) • vent communities • residents include large clams, mussels, anemones, barnacles, limpets, crabs, worms and fishes • primary producers are chemosynthetic bacteria • primary consumers filter-feed or graze bacteria from the water • clams (Calyptogena), mussels (Bathymodiolus) and vestimentiferan worms (Riftia) host symbiotic chemosynthetic bacteria © 2006 Thomson-Brooks Cole

25. Life on the Sea Bottom • Vent communities (continued) • rise and fall of vent communities • vents are colonized by organisms shortly after they are formed • when geological changes inactivate the vent (an estimated 20 years later), these organisms all die • vent inhabitants are thought to produce large numbers of larvae which drift to other vent sites © 2006 Thomson-Brooks Cole

26. Page 415-417: Giants of the Deep Essential Question: What makes deep water creatures so much different than species in sunlit surface waters ? SubEQ: Why are the species larger? How does their environment affect their characterisitcs?

27. Black Smoker- Vent Community http://www.bing.com/videos/watch/?q=black+smoker+vent+&vid=82919E9FAFB7BE3A6BAD82919E9FAFB7BE3A6BAD&docid=436282590703&FROM=LKVR5&GT1=LKVR5&FORM=LKVR1

30. Chemosynthetic Bacteria Chemosynthesis is the process by which food (glucose) is made by bacteria using chemicals as the energy source, rather than sunlight. Bacteria living on the sea floor or within animals, such as mussels and tubeworms, use energy stored in the chemical bonds of hydrogen sulfide and methane to make glucose from water and carbon dioxide (dissolved in sea water).

31. Vocabulary- Echinoderms- animals that have spiny skin ex. Sea stars, sea urchins, sea cucumbers Annelids- segmented worm that belongs to the phylum Annelida Mollusc- a soft bodied animal phylum Mollusca, the bodies of most are covered by a hard shell Photic Zone- the part of the ocean that receives sunlight to support photosynthesis Adaptation- the ability to change or adjust to the surrounding water (environment) atm1

32. Animals found in the abyss need to be able to adapt to cold and pressure. Some of the first animals to be found in the abyss were sea anemones, sea cucumbers, bivalves, amphipods, brissal worms. They were about 10,000 meters deep. atm2

33. Adaptations to Pressure Many several thousand species that can withstand the pressure of the abyss are echinoderms, annelids, and molluscs. So How can they tolerate the pressure? The fluid pressure in the animals’ body matches the pressure of the surrounding water with an equal and opposite force which prevents them from being crushed. (Newton’s 3rd Law) atm3

34. Adaptations to Temperature Most animals in the deep have body temperatures that are close to the temperature of the surrounding water. Their metabolism is quite slow and as a result they move Very slowly and reproduce less. atm4

35. Life in the Dark 3 Major factors affect animals living in the deep ocean - light - temperature - pressure The disphotic zone (twilight zone) is the region 500-1500 ft below the sea surface Many deep sea creatures produce their own light in the form of bioluminescence. bsb1

36. Bioluminescence is most common for animals between 300-2400 meters Bioluminescence occurs when luciferin (a protein found in the animals body) is combined with oxygen in the presence of luciferase (an enzyme which helps the chemical reaction take place) Bioluminescence can be used for camoflauge. During mating time, the pattern of lights identifies if the animal is male or female bsb2

37. Angler fish and Stomiatoids attract their prey with bioluminescence Some species of stomiatoid fish have lights around their eyes Some deep water species of squid use bioluminescent fluid that clouds the water with light thereby confusing predators bsb3

38. Dr. William Beebe, the pioneer of underwater exploration In 1934, he descended to a depth of 3,028 feet in a steel ball known as a Diving Bell stis1

39. Jacques Piccard and Don Walsh used the Bathyscaphe and discovered new animal life at a greater depth reaching the floor of the Marianas Trench The Bathyscaphe is a free diving self propelled deep sea submersible. The cons of a manned submersible are they are too expensive to operate and expose the passengers to too many risks. stis2

40. Benthic Communities • In the bottom of the ocean there is no light • to create photosynthesis • Because of the cold temperature, • it slows the growth of bacteria • The lack of organisms leaves the food chain limited • ndmm1

41. Turbidity currents deliver organic nutrients • to the abyssal plains and trenches • near the continental shelves • Snails and crustaceans are considered • benthic animals that feed on the • carcasses on the ocean floor ndmm2

42. Further away from the benthic shelves, the • available food diminishes, so larger bottom • feeders are absent. • In the deep ocean trenches food is so scarce • that even tiny organisms are rarely found ndmm4

44. Seeing and Feeding in the Dark Vocabulary Aphotic Zone- the portion of the pelagic division where sunlight is absent Depth Perception- allows them to judge the distance to their prey quite accurately Detritus Feeders- food for more active predators Stomiatoid- organism capable of ingesting prey larger than themselves Barbel- a fleshy projection on the head of some of the fishes that may fulfill a sensory role or function as a lure dsp1

45. Essential Questions: How do marine animals see in the dark part of the aphotic zone? What is special about the kind of eyes of deep sea fish? What is an advantage given to deep sea fish because of the way their eyes are? British Biologist N.B. Marshall studied how deep sea fish could see in the dim light of the aphotic zone. He concluded that they see because they have tubular eyes. Each eye contains 2 retinas compared to only one in typical vertebrates. Tubular eyes allow fish to see distant objects with one retina and closer objects with another retina. Therefore, with tubular eyes deep sea fish can easily judge distance of food and predators which is an advantage since food is scarce in the depths of the ocean. dsp2

46. Essential Question: What do they eat? Why? What are nightly or vertical migrations? They eat organic wastes, scraps of food, and dead and dying organisms that drift down from the surface. In the ocean depths there are no photosynthetic organisms to produce food. Chemosynthesis Vertical migration is when small fish and invertebrates rise at night to feed in the surface of the ocean and returning to the depths during the day. dsp3

47. Barbels are lures or projections that probe the bottom ooze (sediment) for food. They may even serve in species recognition during mating. dsp4