CH-13-14 Intertidal Communities – Introduction to Marine Biology : Exam Guide

This Document Contains Chapters 13 to 14 Chapter 13--Intertidal Communities 1. The supralittoral zone is: A. the area below the low tide mark. B. the area above the high tide mark. C. the area between low and high tide marks. D. the area under the rocks. E. The area at the low tide mark. Answer: B. the area above the high tide mark. 2. Most of the animals living in the rocky intertidal are: A. infaunal. B. epifaunal. C. epiphytic. D. meiofaunal. E. pelagic. Answer: B. epifaunal. 3. The organisms of the intertidal are subject to daily changes in all except: A. exposure to air. B. desiccation. C. wind and waves. D. low light levels. E. heat. Answer: D. low light levels. 4. During winter months in temperate environments organisms can die from: A. high rain fall. B. freezing. C. low sunlight. D. increased predation. E. increased pH level. Answer: B. freezing. 5. Lichens of the supralittoral fringe are compound associations between: A. algae and bacteria. B. fungi and bacteria. C. bacteria and cyanobacteria. D. fungi and algae. E. algae and cyanobacteria. Answer: D. fungi and algae. 6. A tar-like patch found in the upper North Atlantic supra-intertidal usually is: A. a lichen. B. a cyanobacteria. C. sea hair. D. a sponge. E. a seaweed. Answer: B. a cyanobacteria. 7. Rough periwinkles that live in the splash zone use _______________ for respiration. A. gills B. lungs C. the mantle D. the foot E. the radula Answer: C. the mantle 8. The rough periwinkles protect exposure of eggs by: A. producing planktonic eggs inside jelly coats. B. attaching gelatinous egg masses to large algae. C. retaining the eggs in the mantle cavity. D. providing a protective membrane around the eggs. E. dispersing them into the water column. Answer: C. retaining the eggs in the mantle cavity. 9. Barnacles such as Balanus dominate in the _______________ zone of the rocky intertidal. A. upper midlittoral B. middle midlittoral C. lower midlittoral D. subtidal E. splash Answer: A. upper midlittoral 10. Sea urchins living in the rocky intertidal zone use the following method to overcome wave shock: A. creating burrows in which they live. B. having a low profile. C. using spines to dissipate the energy of the wave. D. All of these. E. None of these. Answer: D. All of these. 11. Rockweeds overcome the problems of desiccation by: A. growing only in shaded areas. B. having a gelatinous covering. C. evaporating water from their tissues. D. bending with the waves. E. being covered with a waxy cuticle. Answer: B. having a gelatinous covering. 12. The upper limit of an organism's distribution in the rocky intertidal is usually determined by: A. grazing effect. B. predation. C. pH. D. desiccation. E. competition. Answer: D. desiccation. 13. Supralittoral isopods are: A. predators. B. herbivores. C. detritivores. D. scavengers. E. grazers. Answer: D. scavengers. 14. Supralittoral isopods: A. must have some salt water cover daily. B. would drown if placed in water. C. return to the sea to lay eggs. D. have pseudogills. E. prey on barnacles. Answer: B. would drown if placed in water. 15. On very wavy rocky shores, mussels will occupy the _______________ zone without being affected too much by predation. A. lower intertidal B. upper intertidal C. middle intertidal D. supratidal E. splash Answer: A. lower intertidal 16. On Pacific coasts, the population of mussels is kept in check by predation from: A. sea otters. B. sea stars. C. sea urchins. D. barnacles. E. supralittoral isopods. Answer: B. sea stars. 17. The size of sediment particles on sandy beaches will influence the following characteristic of the beach: A. porosity. B. oxygen content. C. food content. D. rate of water drainage. E. All of these. Answer: E. All of these. 18. Most of the animals living in the sandy intertidal are: A. infaunal. B. epifaunal. C. epiphytic. D. planktonic. E. nektonic. Answer: A. infaunal. 19. The area with the highest species diversity among the following is: A. rocky subtidal. B. sandy subtidal. C. sandy intertidal. D. rocky supratidal. E. splash zone. Answer: A. rocky subtidal. 20. _______________ is common in sandy intertidal areas. A. Predation B. Algal grazing C. Deposit feeding D. Parasitism E. All of these. Answer: C. Deposit feeding 21. An example of a filter feeder is: A. a mussel. B. a sea star. C. a crab. D. a nematode. E. an isopod. Answer: A. a mussel. 22. Grain size in the intertidal is primarily determined by: A. wave activity. B. types of animals in the area. C. amount of sunlight. D. feeding types in the sediment. E. burrowing activity of infauna. Answer: A. wave activity. 23. Intertidal soft bottoms are unstable due to: A. wave action. B. erosion. C. changing tides. D. currents. E. All of these. Answer: E. All of these. 24. Ghost crabs predominate in: A. sandy supratidal. B. sandy intertidal. C. sandy subtidal. D. rocky shores. E. splash zones. Answer: A. sandy supratidal. 25. Which of the following is false about rocky shores? A. Mangroves are common. B. Silt is removed by waves. C. They have fewer of the finer sediments. D. Surf functions to oxygenate the water. E. Sessile organisms are common. Answer: A. Mangroves are common. 26. Mussels attach to the rocky shores by: A. byssal threads. B. mucous secretions. C. foot. D. calcareous shells. E. glue. Answer: A. byssal threads. 27. The following is not a common feeding type in rocky intertidal areas: A. filter. B. scavenger. C. grazer. D. deposit. E. carnivore. Answer: D. deposit. 28. The midlittoral zone of temperate rocky shores are divided into all except: A. the upper midlitoral. B. the middle midlittoral. C. the low midlittoral. D. the sub midlittoral. E. None of these. Answer: D. the sub midlittoral. 29. Oysters dominate this rocky shore zone. A. The middle and low midlittoral. B. The subtidal zone. C. The supralittoral fringe. D. The upper midlittoral. E. The splash zone. Answer: A. The middle and low midlittoral. 30. A tidepool exposes organisms to all the following except: A. dessication. B. thermal stress. C. salinity changes. D. pH changes. E. dissolved oxygen changes. Answer: A. dessication. 31. Tidepool organism adaptations to changing conditions are similar to those of the ______________. A. mudflat B. salt marsh C. sandy beach D. mangals E. open ocean Answer: B. salt marsh 32. _______________ factors determine which type of algae species will predominate in tide pools in New England. A. Bottom-up B. Top-up C. Abiotic D. Biotic E. Physical Answer: D. Biotic 33. The macroplants of the midlittoral temperate Pacific and Atlantic are characterized by: A. red algae. B. green algae. C. brown algae. D. seagrasses. E. mangals. Answer: C. brown algae. 34. The dominant producers of the infralittoral fringe in temperate Pacific and Atlantic are the: A. foliose red algae. B. green algae. C. large brown algae. D. eelgrass. E. calcareous red algae. Answer: C. large brown algae. 35. The supralittoral fringe of the tropics contains all the following zones except: A. brown. B. white. C. gray. D. black. E. None of the above. Answer: A. brown. 36. The true border between land and sea in the tropics is called the _______________ zone. A. brown B. white C. gray D. black E. yellow Answer: B. white 37. The organism in the tropics that replaces limpets in the supralittoral fringe is: A. turtle grass. B. nerites. C. the hermit crab. D. knobby periwinkle. E. the coconut crab. Answer: B. nerites. 38. The supralittoral zone immersed only at the highest spring tides is the: A. brown. B. white. C. gray. D. black. E. yellow. Answer: D. black. 39. The upper distribution of nerites can be found in the _______________ zone. A. brown B. white C. gray D. black E. yellow Answer: C. gray 40. The midlittorial fringe has two zones; they are: A. brown and yellow. B. brown and pink. C. black and white. D. brown and black. E. pink and yellow. Answer: E. pink and yellow. 41. The yellow zone owes its color to: A. sponges. B. boring algae. C. barnacles. D. limpets. E. crabs. Answer: B. boring algae. 42. The pink zone is characterized by the widespread: A. irregular worm snails. B. coralline algae. C. anemones. D. keyhole limpets. E. barnacles. Answer: B. coralline algae. 43. A common organism of the infralittoral fringe is called: A. Sargassum. B. Entermorpha. C. Ulva. D. lichen. E. giant kelp. Answer: A. Sargassum. 44. Some resident intertidal fish include all the following except: A. rock eels. B. lamprey eels. C. gobies. D. sculpins. E. blennies. Answer: B. lamprey eels. 45. The upper sandy beach often ends: A. where sand dunes begin. B. where terrestrial vegetation begins. C. at the high tide line. D. where sand dunes begin and where terrestrial vegetation begins. E. where terrestrial vegetation begins and at the high tide line. Answer: D. where sand dunes begin and where terrestrial vegetation begins. 46. Most of the organisms of the supralittoral fringe of sandy beach cope by: A. moving out of the area during low tide. B. clamming up. C. living in permanent or semi-permanent tubes and burrows. D. tolerating desiccation. E. migrating into upper tidal zones. Answer: C. living in permanent or semi-permanent tubes and burrows. 47. Which zone does not occur in the sandy beach? A. Resurgence. B. Drying sand. C. Beach hopper. D. Retention. E. None of these. Answer: C. Beach hopper. 48. Primary production in the sandy beach is primarily by: A. seagrasses. B. diatoms. C. dinoflagelletes. D. mangals. E. diatoms and dinoflagelletes. Answer: E. diatoms and dinoflagelletes. 49. The zone exposed only during spring tides is called: A. subtidal. B. sublittoral. C. laminaria. D. seagrass. E. splash. Answer: A. subtidal. 50. On many coasts the subtidal zone contains very productive: A. seagrass meadows. B. Laminaria seaweeds. C. Ulva flats. D. seagrass meadows and Laminaria seaweeds. E. Laminaria seaweeds and Ulva flats. Answer: D. seagrass meadows and Laminaria seaweeds. 51. Sessile organisms predominate on sandy/muddy subtidal habitats. Answer: False 52. Sea stars are not sensitive to desiccation and hence are found in the high intertidal. Answer: False 53. Organisms living in the intertidal zone are most active during low tide. Answer: False 54. Zonation on a rocky intertidal zone refers to the distribution of different kinds of rocks from one area to the next. Answer: False 55. Animals living in the supralittoral fringe must be able to deal with the force of wave shock. Answer: False 56. Mussels outcompete barnacles for space in the middle intertidal zone of the rocky intertidal. Answer: True 57. Tide pools offer refuge to intertidal animals because they are not subject to wild fluctuations in temperature and salinity. Answer: False 58. The pH of a tide pool can change dramatically over short time periods. Answer: True 59. Barnacles are more adept than mussels at withstanding the effect of desiccation. Answer: True 60. Beaches with heavy wave action tend to have finer sand particles and are flat. Answer: False 61. Unlike rocky beaches, sandy beaches have vertical zonation of organisms that live in the sediment. Answer: True 62. Coquinas are carried up the beach for filter feeding by the waves. Answer: True 63. Space is not a limiting factor on a rocky intertidal beach. Answer: False 64. Match the zone with those it is most closely associated with in the Stephensons' classification system. 1. Supralittoral splash zone 2. Midlittoral maritime zone 3. Supralittoral fringe intertidal zone Answer: 65. Match the organism with the most closely associated tidal zone. 1. Upper midlittoral periwinkles 2. Supralittoral fringe acorn barnacles 3. Middle zone mussels Answer: 66. Match the plant with the zone it is most closely associated with. 1. Midlittoral rockweeds 2. Supralittoral fringe lichens 3. Infralittoral fringe Laminaria Answer: 1 67. Match the species with the zone it is most closely associated with. 1. Black zone knobby periwinkle 2. White zone nerites 3. Gray zone fuzzy chiton Answer: 68. Match the algae with the zone it is most closely associated with. 1. Infralittoral fringe boring algae 2. Yellow Zone coralline algae 3. Pink Zone Sargassum Answer: 69. Match the sandy beach characteristic with the term. 1. Swash the water running up the beach 2. Backwash the water flowing back down the beach 3. Reflective beach surf zone 4. Dissipative beach lacks a surf zone Answer: 70. Match the wave action with the sandy beach exposure level. 1. Semi-exposed high 2. Protected moderate 3. Very Protected low 4. Exposed none Answer: 71. Match the wave type with the sandy beach exposure level. 1. Protected plunging, surging 2. Semi-Exposed spilling 3. Exposed none Answer: 72. Match the moisture source with the vertical sandy beach zone during low tide. 1. Saturation due to capillary action of water 2. Resurgence low tide water retained 3. Retention continuous water Answer: 73. Match the food source with the organism. 1. Mole crab plankton 2. Sand dollar bivalves 3. Moon snail meiofauna 4. Lugworm detritus Answer: 74. List the zones that comprise rocky shores. Which of the zones would you expect to have the highest species diversity and which would have the lowest species diversity? Explain your answer. Answer: The three zones of rocky shores are the splash zone, the intertidal zone, and the subtidal zone. Species diversity is highest in the subtidal zone as a result of the greater stability of this zone. Animals are nearly always submerged in the subtidal, which means they will always have oxygen and food. Wave action in the subtidal is also reduced. The ultimate result is that more species can occupy this area without suffering as they would in the upper reaches of the intertidal. 75. List the zones that comprise the sandy shores. Which zone has the highest diversity and which has the lowest? Explain your answer. Answer: In the supralittoral and midlittoral zones the surface and near surface have the dry zone, and drying zones. Just below this area is the retention zone. Closer to the ocean and deeper is the zone of retention; eventually the saturation zone is reached. The highest diversity occurs in the saturation zone because it remains moist for the organisms. The dry zone conversely has the lowest diversity because of desiccation. 76. Describe what constitutes a lichen. How do they obtain their nutrition? Where are they usually found in the rocky intertidal? Answer: Lichens are symbiotic associations between algae and fungi. The algae supply the association with food from photosynthesis, while the fungus supplies nutrients from its decomposition and waste products. Lichens are common in the supralittoral fringe of rocky shores. 77. List at least 3 adaptations of rocky intertidal animals to resist desiccation. Answer: Animals living in the rocky intertidal show a number of adaptations against desiccation. Among these are choosing special living arrangements within crevices or among other animals of the same species. This reduces water loss by decreasing the exposed surface area. Many animals can also close their shells when exposed in order to conserve water within. In addition, some animals can simply pick up and move out of exposed areas to tidepools or to the water line. 78. How do intertidal brown algae compete with barnacles and mussels for space? Answer: These macrophytes use the sweeping motion of the blades to prevent settling cyprid larvae of barnacles and pediveligers of mussels from getting a hold onto the rocks nearby. 79. Even though rocky shores are subject to some of the same abiotic factors as estuarine habitats, such as changes in temperature and salinity, the species diversity is much higher in the former than the latter. What other variables do you think contribute to this high species diversity in the rocky intertidal? Answer: The most notable difference between the two habitats is the greater number of diverse microhabitats in the rocky environment than in estuaries. This means that there are more niches that can be exploited by animals living in the rocky intertidal, which results in a greater species diversity. 80. What are at least 3 adaptations that rocky intertidal organisms have for withstanding wave shock? Answer: Depending on the species, some organisms, like chitons and limpets, have very low profiles in order to minimize wave contact. These animals can use their foot for adhering to the rock surface, whereas other organisms use tube feet (sea stars), byssal threads (mussels), cementing materials (oysters and barnacles), or a holdfast (algae). Other adaptations include hiding under rocks or between rock crevices, and having strong but flexible bodies (brown algae). 81. Compare the sandy intertidal and rocky intertidal with respect to the types of feeding exhibited by the animals living in those areas. Answer: Since the rocky intertidal is so wave swept, and since the substrate is hard and does not absorb food particles, deposited materials tend to get washed away with the receding tides and waves. As a result, deposit feeding is uncommon in the rocky intertidal, with the possible exception of tide pools. Sandy beaches, on the other hand, have larger accumulations of deposited material that is retained by the soft sediments in these areas. Deposit feeders are more common here than in rocky areas. In both rocky and sandy intertidal areas, filter feeding is prevalent due to the abundance of water-born food particles. Scavenging and predation are also common in these two areas. 82. The base of the food web in sandy intertidal areas exposed to wave action is detritus, not algae. What prevents attached algae and marine plants from occupying this niche? Answer: Attached plants are not common in these areas because there is not permanent hard substrate to which these algae can attach. As a result, animals must rely on detritus produced from offshore kelp beds or benthic algae or detritus formed in nearby estuaries. In contrast, rocky shores are covered with algae, which can be grazed directly by rocky intertidal animals. 83. How does the introduction of predators to a habitat decrease the effects of competition between two other species? Answer: Predators can control the population of one of the species that is in competition with another species. If the species being preyed upon is dominant over the other species, then the effect of the predator will be to give refuge to the less successful competitor and it will be able to withstand the competitive pressures of the dominant competitor. Chapter 14—Estuaries 1. Drowned river valley estuaries were formed by: A. tectonic activity. B. the scoring effect of glaciers. C. rising sea levels after glacial periods. D. tectonic activity and the scoring effect of glaciers. E. None of these. Answer: C. rising sea levels after glacial periods. 2. Estuaries in which river flow is strong and prevents the flow of seawater upstream are called: A. fjords. B. salt-wedge estuaries. C. well-mixed estuaries. D. tectonic estuaries. E. drowned river valleys. Answer: B. salt-wedge estuaries. 3. When retreating glaciers carved deep coastal valleys they created: A. fjords. B. salt-wedge estuaries. C. well-mixed estuaries. D. tectonic estuaries. E. drowned river valleys. Answer: A. fjords. 4. An example of a salt-wedge estuary is: A. the Mississippi Delta. B. Delaware Bay. C. Chesapeake Bay. D. Puget Sound. E. All of these. Answer: A. the Mississippi Delta. 5. San Francisco Bay was created by: A. rising sea levels. B. retreating fjords. C. erosion of the coastline. D. tectonic activity. E. glaciers. Answer: D. tectonic activity. 6. Where rivers slow and drop their sediment load they form deltas termed: A. dendritic. B. coastal plain. C. tidal flats. D. sand bar. E. tombolos. Answer: C. tidal flats. 7. When sediment removal is less than input we often find: A. fjords. B. tectonic estuaries. C. tidal flats. D. bar-built estuaries. E. drowned river valleys. Answer: D. bar-built estuaries. 8. In a well-mixed estuary, river flow is _______________ tidal currents. A. greater than B. less than C. perpendicular to D. equal to E. none of these Answer: B. less than 9. What causes tidal overmixing in estuaries? A. Strong tidal currents. B. Strong river flow. C. An unstable water column. D. Downwelling. E. Animal migrations. Answer: C. An unstable water column. 10. When dense seawater sinks below lighter fresh water we observe a condition called: A. downwelling. B. salt wedge. C. tidal overmixing. D. upwelling. E. convection current. Answer: C. tidal overmixing. 11. An estuary where freshwater inflow is greater than evaporation is called a: A. negative estuary. B. positive estuary. C. reversible estuary. D. neutral estuary. E. salt-wedge estuary. Answer: B. positive estuary. 12. An example of a negative estuary is: A. Delaware Bay. B. Puget Sound. C. Laguna Madre. D. San Francisco Bay. E. Chesapeake Bay. Answer: C. Laguna Madre. 13. It is common for negative estuaries to be: A. lower in salinity than the ocean. B. nutrient poor. C. nutrient rich. D. lower in temperature than the ocean. E. brackish. Answer: B. nutrient poor. 14. In a salt-wedge estuary the relationship between salinity and depth is that salinity: A. is even from top to bottom. B. increases with depth. C. changes abruptly with depth. D. varies horizontally. E. decreases with depth. Answer: B. increases with depth. 15. In a partially mixed estuary the salinity: A. is extremely variable from place to place. B. is stratified with lower salinity near the bottom. C. is lower than the ocean but relatively homogenous. D. increases with depth. E. is extremely variable from place to place and is lower than the ocean but relatively homogenous. Answer: C. is lower than the ocean but relatively homogenous. 16. In northern estuaries which of the following factors influences mixing? A. Oxygen concentrations. B. Nutrient concentrations. C. Carbon dioxide concentrations. D. Temperature. E. Turbidity. Answer: D. Temperature. 17. Estuaries tend to be well supplied in the following limiting nutrient(s) of the open ocean: A. phosphorus. B. nitrogen and silica. C. phosphorus and silica. D. nitrogen and phosphorus. E. carbon and oxygen. Answer: C. phosphorus and silica. 18. Pseudofeces are: A. semisolid deposits containing un-digested material. B. semisolid deposits of digested material. C. solid deposits containing un-digested material. D. solid deposits containing digested material. E. All of these. Answer: A. semisolid deposits containing un-digested material. 19. The concentration of nutrients in estuaries leads to them having _______________ productivity. A. extremely low B. low C. average D. medium E. high Answer: E. high 20. The number of resident species in estuaries tend to be ________________ relative to nearby ecosystems. A. an order of magnitude higher B. greater C. about the same D. fewer E. about the same or fewer. Answer: D. fewer 21. Which factor currently tends to regulate abundance of estuary species such as oysters and crabs? A. Competition. B. Predation. C. Human activities. D. Normal seasonal die off. E. Disease. Answer: C. Human activities. 22. All of the following tend to hold nutrients in estuaries for use by aquatic plants except: A. adsorption onto silt particles. B. reduced numbers of filter feeders. C. the formation of pseudofeces. D. overturn. E. adsorption onto silt particles and reduced numbers of filter feeders. Answer: B. reduced numbers of filter feeders. 23. An animal that maintains a constant salt concentration in their body is called: A. an osmoconformer. B. an osmoregulator. C. hyper-osmotic. D. hypo-osomotic. E. a hyper-osmoregulator. Answer: B. an osmoregulator. 24. An example of an osmoregulator at low salinities and an osmoconformer at higher salinities is a(n): A. blue crab. B. salmon. C. oyster. D. sea squirt. E. tuna. Answer: A. blue crab. 25. The animals that remain isosmotic to the surrounding seawater are called: A. osmoconformers. B. osmoregulators. C. hyperosmotic. D. hyposmotic. E. euryhaline. Answer: A. osmoconformers. 26. An example of an osmoconformer is: A. a crab. B. a polychaete worm. C. a fish. D. a sea squirt (tunicate). E. All of these. Answer: D. a sea squirt (tunicate). 27. All of the following are adaptations against excessive water and salt exchange between animals and their surrounding environment except: A. having very permeable tissues. B. covering body with mucus. C. living inside a tube that can be isolated from the external environment. D. covering the body with a hard exoskeleton. E. actively absorbing salt ions with gills. Answer: A. having very permeable tissues. 28. All of the following are adaptations to remain stationary in the ever-shifting soft bottom of estuaries except: A. plants with extensive roots and rhizomes. B. algae with holdfasts. C. animals attached to the bottom. D. drifting with the currents. E. byssal threads. Answer: D. drifting with the currents. 29. Estuaries for many transient species are considered: A. a place to spawn. B. nurseries. C. too full of predators for juveniles. D. very stable environments. E. All of these. Answer: B. nurseries. 30. An example of a species that uses the estuary as a nursery ground is the: A. Atlantic eel. B. seal. C. shad. D. lobster. E. tuna. Answer: C. shad. 31. A euryhaline species can tolerate: A. a wide range of temperatures. B. a narrow range of temperatures. C. a wide range of salinities. D. a narrow range of salinities. E. a narrow range of temperatures and a wide range of salinities. Answer: C. a wide range of salinities. 32. All are true of oyster reefs except: A. they are oriented perpendicular to currents. B. they are concentrated in lower salinity areas. C. they are important habitats for other organisms. D. they are adversely affected by rapid changes in salinity. E. they are increasing in the Chesapeake Bay. Answer: E. they are increasing in the Chesapeake Bay. 33. Larval oysters attach themselves to: A. They do not have specific requirements. B. any available solid substrate. C. other oyster shells. D. any available solid substrate and other oyster shells. E. sand. Answer: D. any available solid substrate and other oyster shells. 34. Oysters generally settle at right angles to tidal currents. These currents: A. carry food away from the oysters. B. clear sediments from the oysters. C. help them avoid oyster drills. D. deposit sediments among the oysters. E. clear sediments from the oysters and help them avoid oyster drills. Answer: B. clear sediments from the oysters. 35. Ecologically mud flat areas are a focal area of: A. nutrient recycling. B. primary production. C. tertiary consumers. D. nutrient sink. E. sessile epifauna. Answer: A. nutrient recycling. 36. The energy base on mud flats is: A. phytoplankton. B. detritus. C. marsh plants. D. algae. E. chemosynthesis. Answer: B. detritus. 37. Most of the animals of mud flats are: A. planktonic. B. epifaunal. C. oysters. D. infaunal. E. nektonic. Answer: D. infaunal. 38. Many of the burrowing animals of the mud flat must actively: A. keep digging to exchange gasses. B. circulate water through their burrows. C. live near natural breaks in the sediment for gas exchange. D. maintain an anaerobic environment. E. circulate water through their burrows and live near natural breaks in the sediment for gas exchange. Answer: B. circulate water through their burrows. 39. Ghost shrimp live: A. in burrows. B. under rocks on the mud flat. C. on the surface of the mud. D. in the water above the mud flat. E. symbiotically with bivalves. Answer: A. in burrows. 40. Ghost shrimp and mud shrimp play an active role in: A. compacting the sediment. B. reducing species through competition. C. decomposition of seagrass roots. D. oxygenating the sediments. E. consuming marsh plants. Answer: D. oxygenating the sediments. 41. Seagrasses can reach high productivity levels with the aid of: A. oxygen brought to their roots via mud shrimp burrows. B. symbiotic, nitrogen-fixing bacteria. C. their leaves, cleared of epiphytes by grazers. D. fertilization by manatees. E. eutrophic water conditions. Answer: B. symbiotic, nitrogen-fixing bacteria. 42. Seagrasses are important in all the following except: A. nutrient recycling. B. providing a habitat for animals. C. stabilizing sediments. D. being consumed by most estuarine herbivores. E. None of these. Answer: D. being consumed by most estuarine herbivores. 43. A common direct consumer of eelgrass (Zostera) are: A. snails. B. waterfowl. C. sea cucumbers. D. manatees. E. sea stars. Answer: B. waterfowl. 44. Caribbean seagrasses are extensively fed on by all except: A. manatees. B. green sea turtles. C. some sea urchins. D. sea cucumbers. E. None of these. Answer: D. sea cucumbers. 45. The dominant plant species closest to the water line of salt marsh communities is: A. cordgrass. B. pickleweed. C. spike grass. D. salt wort. E. mangroves. Answer: A. cordgrass. 46. Marsh plants are important in all of the following except: A. trapping sediments. B. serving as a refuge for animals. C. being directly consumed food. D. stabilizing sediments. E. None of these. Answer: C. being directly consumed food. 47. Pneumatophores of black mangroves are: A. prop roots. B. aerial roots. C. germinated seeds. D. pores on leaves. E. salt-excreting structures. Answer: B. aerial roots. 48. All estuaries are diluted by freshwater runoff. Answer: True 49. Estuaries are immune from larger temperature variations. Answer: False 50. Seawater and fresh water do not mix very well in fjords. Answer: True 51. The major source of nitrogenous nutrients in estuaries is incoming seawater. Answer: False 52. The species diversity in estuaries is high, but the number of individuals is low. Answer: False 53. Estuaries are important nurseries because of the relatively low numbers of predators in these areas. Answer: True 54. Mud flats of estuaries are very porous. Answer: False 55. Most burrowing animals of estuaries exchange gases with their environment through their skin. Answer: False 56. Seagrasses are usually consumed directly by grazers in estuaries. Answer: False 57. Salt marsh communities predominate in temperate and subarctic areas. Answer: True 58. Salt marsh plants play an important role in expanding the terrestrial environment. Answer: True 59. Mangrove forests predominantly occur in temperate regions. Answer: False 60. Match the mangrove ecosystem species with its most closely associated trophic level. 1. Detritivore mangrove 2. Secondary consumer heterotrophic bacteria 3. Primary producer amphipod Answer: 3 61. Match the plant with its most closely associated substrate attachment method. 1. Pneumatophores red mangrove 2. Prop roots seagrasses 3. Holdfast algae 4. Rhizomes black mangrove Answer: 62. Match the process/epoch with its most closely associated estuary type. 1. Fjord inter-glacial periods 2. Coastal plain glacial formed 3. Tectonic land movement Answer: 63. Match the process with its most closely associated result. 1. Bar-built sediment deposition at the upper river mouth 2. Fjord sediment based barrier islands 3. Tidal flats water-filled, steep-sided valleys Answer: 64. Match the words with those they are most closely associated with. 1. Bar-Built estuaries Long Island Sound 2. Drowned river valley Cape Hatteras region 3. Fjord Scandinavia estuaries Answer: 65. Match the process with its most closely associated estuarine mixing type. 1. Positive estuary dense surface seawater mixes into freshwater below 2. Tidal overmixing fresh water flows over seawater 3. Negative estuary evaporation can exceed freshwater input Answer: 66. Match the area with the type of estuary. 1. Well-mixed estuary Sacramento River mouth in San Francisco Bay 2. Partially-mixed estuary Delaware Bay 3. Salt-wedge estuary Puget Sound Answer: 67. Match the species with its most closely associated salinity concentration type. 1. Osmoconformer tunicates 2. Osmoregulator hermit crab 3. Both osmoconformer and osmoregulator Nereis polychaetes Answer: 68. Match the genus with its most closely associated common name. 1. Oyster drill Urosalpinx 2. Clam Ulva 3. Algae Mya Answer: 69. Match the herbivore with its most closely associated primary producer. 1. Zostera green turtles 2. Diatoms waterfowl 3. Thalassia soft-shell clam Answer: 70. Outline 3 human uses of estuaries that impact their ecology. Answer: Humans rely on important estuary-dependent species for food such as oysters, crabs, scallops, shrimp, and fish. Human dredging and filling in of estuaries combined with pollution affect the size and quality of estuaries. Up-river dams modify the flow of water, sediment, and woody debris that historically influenced the physical environment of the estuary. 71. Define the following terms: • Estuary • Tidal flat • Salt-wedge estuary Answer: An estuary is a semi-enclosed body of water where freshwater from a river meets saltwater from the sea. Tidal flats are sediment deposits that accumulate in river mouths and are exposed during low tide. A salt-wedge estuary is one in which river flow into the estuary is strong enough to force back the upper reaches of the lower layer of seawater coming into the estuary. The result of such action is to create a narrow wedge of seawater moving up the estuary. 72. Define the following terms: • Coastal plain estuary • Tectonic estuary • Fjord Answer: A coastal plain estuary is formed between glacial periods when water from melting glaciers causes the sea level to rise and flood coastal plains and low-lying rivers. A tectonic estuary is created when earthquakes cause the land to sink, allowing seawater to cover it. A fjord is a glacial cut deep valley filled with water. 73. How does temperature-driven vertical turnover occur, and what is its importance? Answer: Vertical turnover occurs in estuaries in which the upper layer of water is cooled in the winter. This cooling results in denser surface water than water below and causes surface water to sink and deeper water to rise to the top. Turnover has the effect of allowing nutrients to cycle between the water column and the sediments. 74. What properties of estuaries make them highly productive areas? Answer: Estuaries are very productive because they act as nutrient sinks. The abundance of nutrients supports the growth of phytoplankton, algae, and emergent plants, all of which support secondary production in estuaries and elsewhere. Nutrients are trapped in estuaries as a result of nutrient input from the sea and from rivers; adsorption of nutrients onto sinking particles; and the ejection of pseudofeces by benthic filter feeders at the bottom of estuaries. 75. Describe the difference between an osmoregulator and an osmoconformer. Answer: Animals in estuaries fall under the categories of euryhaline osmoconformers, which tolerate drastic dilution or concentration of their tissue fluids, and osmoregulators that control the concentration of salts in their tissue very closely. 76. Considering that species diversity in estuaries is limited by constant changes in salinity, temperature, and water movement, where, vertically, in an estuary would one expect to find the greatest species diversity? The least species diversity? Answer: Looking at the vertical zones of an estuary, one finds the greatest species diversity in the sediments of estuaries. The reason for this is that fine sediments of estuaries trap a layer of interstitial seawater that does not change its salinity and temperature as drastically as overlying water. For this reason the sediments of estuaries are more stable environments and support a greater species diversity. Below the aerobic sediments, in the anoxic zone, few species other than methanogenic bacteria are found. 77. What horizontal part of an estuary would you expect to show the greatest species diversity? Answer: Since most estuarine animals are either marine or brackish species, the greatest diversity of organismswould occur in areas far from freshwater discharge. 78. Even though estuaries support large numbers of organisms, there are relatively few numbers of species that live in estuaries. Why is this the case? Answer: Estuaries are among the most productive marine environments. High levels of nutrients support large numbers of primary producers, which in turn support large numbers of consumers. The low species diversity of estuaries stems from the instability that characterizes this environment. Salinity fluctuates widely between seasons and from day to day. Temperature also fluctuates widely on a daily and seasonal basis. In addition, habitats in estuaries are subjected to strong currents and lowered oxygen levels, which make life a bit difficult in these areas. As a result, only animals that are adapted to a wide range of environmental conditions can survive in these areas and prosper and this has the effect of lowering the species diversity in these areas. 79. Why are estuarine environments ideal locations for the development of juveniles of many species of marine animals? Answer: The primary reasons for the suitability of estuaries as nurseries is the low number of potential predators and the plentiful food supply. 80. Oyster reefs are usually oriented at right angles to the currents in estuaries. How do you think this could be an advantage to the oysters living in this community? Answer: The perpendicular arrangement of oyster reefs in estuaries provides the animals that comprise the reef with the greatest amount of exposure to tidal currents and river flow. This ensures that the animals will benefit from better access to food, nutrients, and oxygenated water and will enable the removal of a great amount of debris and silt that settles on the reef. Test Bank for Introduction to Marine Biology George Karleskint, Richard Turner, James Small 9780495561972, 9780534420727