Chapter 12 - 16 Practice & Review Questions
How does sonar work?
A sound signal is bounced off the ocean floor.
Describe the mechanism by which bioluminescence is accomplished in deep-sea organisms.
About 80% of bioluminescent organisms have light-producing organs called photophores. Light may be produced from substances that form during digestion, from specialized cells, or from symbiotic bacteria. A biological pigment called luciferin emits photons, which are packets of light, when oxygen is present or produced.
List several adaptations of deep-water nekton that allow them to survive in their environment.
Adaptions deep-water nekton have developed are bioluminesence,hinged jaws, large jaws in comparison to their proportion, and expandable stomachs.They also have developed good sensory devices such as long antennae and have low metabolic rates to help conserve food.
Describe the environmental conditions required for development of coral reefs.
An environment suitable for coral reef growth must have a minimum average monthly temperature that exceeds 18°C (64°F) throughout the year. Reef building corals rely on photosynthetic dinoflagellates (zooxanthellae) that live within their tissues. As a result of this relationship, corals survive only in sunlit waters. Strong water circulation assures an adequate supply of food and oxygen. The water must also have normal salinity and have relatively low turbidity (low amount of suspended sediment) because suspended clay, silt, and detritus particles block light and can smother the coral. Additionally, corals need a hard substrate for attachment.
What factors contribute to world-wide sea level rise? Based on tide measurements, how much sea level rise has occurred in the past 150 years?
As stated in the previous answer, sea level rise has occurred due to the melting of polar ice sheets, land glaciers and small ice caps as well as thermal expansion of warmer water at all ocean depths. Over the past 150 years, there has been a global sea level rise of between 10-25 centimeters with certain stations having up to 40 centimeters of sea level rise. According to satellite altimetry, since the early 1990s, there has been an global increase in sea level of about 3 mm per year. These are all faster rates than at any other time over the past 4000 years.
How does water temperature affect the water's ability to hold gases? How do marine organisms extract the dissolved oxygen from seawater?
As water's temperature increases, water's ability to dissolve gasses decreases and as water's temperature decreases, water's ability to dissolve gasses increases. Marine organisms such as fish extract dissolved oxygen from water by sucking water in through their mouths and pushing it through their gills where the oxygen is extracted from the water, and expel the excess water through the gills slits.
List the subdivisions of plankton and benthos, and the criteria used for assigning individual species to each. #2
Benthos Infauna - sediment-dwelling benthos Epifauna - bottom-dwelling benthos Nektobenthos - animals that live on the bottom but are capable of swimming in the water above the bottom.
What is bioluminescence useful for in the marine environment?
Bioluminescence is useful for finding food or attracting prey, marking territory, communication, confusing predators, avoiding predators with distraction, or camouflage by using belly lights to simulate sunlight from above.
Why has the carbon dioxide level of the atmosphere been rising for more than 150 years? How does this contribute to the greenhouse effect that we discussed earlier in the course?
Carbon dioxide concentrations in the atmosphere have been rising for more than 150 years due to human activities, including fossil fuel burning by industry all of the way back to the Industrial Revolution, automobile use, pollution and deforestation. This enhances the greenhouse effect, leading to more trapping and transmitting of Earth's outgoing infrared radiation.
Discuss chemosynthesis as a method of primary productivity. How does it differ from photosynthesis?
Chemosynthesis and photosynthesis are both ways of obtaining energy from your surroundings, but chemosynthesis uses chemicals around it to make energy whereas photosynthesis uses light to make energy. It is used in areas where there is no sunlight and an abundance of chemicals to turn into energy.
What is coral bleaching? How does it occur?
Coral bleaching is the loss of color in coral reef organisms that causes them to turn white. The cause of coral bleaching is due to the removal or expulsion of the coral's symbiotic partner, the zooxanthellae (endosymbiotic dinoflagellates), due to elevated seawater temperature or other environmental stresses.
The golden algae include two classes of important phytoplankton. Compare their composition and structure of their tests.
Diatoms secrete a siliceous cell wall composed of two halves (valves) that are an important constituent of siliceous sediment called diatomaceous earth that is used in filtering devices, industrial abrasives, polishing agents, and numerous other applications. Diatomaceous earth accumulates on the sea floor beneath surface waters that are relatively low in temperature such as in high-latitude regions where equatorial upwelling occurs. Coccolithophorids are covered with tiny calcareous plates (coccoliths) that are abundant in calcareous oozes found on the sea floor beneath warm surface waters (not too deep because the calcium carbonate goes into solution below the calcite compensation depth [CCD]).
How are echolocation and sonar different?
Echolocation is used by dolphins and whales, whereas sonar is a data collection tool developed by people.
Explain why everything in the ocean at depths below the shallowest surface water take on a blue-green appearance.
Even though there is a thicker column of sunlit water in the open ocean far from the continents than in the turbid water near their shores, photosynthesis is greatly restricted in the clear open ocean water by the lack of nutrients in surface waters.
The symbiotic relationship between coral and zooxanthellae is the zooxanthellae provide a constant supply for the coral and the coral provides the zooxanthellae with nutrients. Rising sea surface temperatures causes corals to stress and eventually expel the algae from themselves causing them the bleach. Because at this point the corals are extremely stressed they are at a high risk of mortality. Although they can recover, if they don't recover within a certain amount of time they will die.
Explain and identify the symbiotic relationship between coral and algae (zooxanthellae). How can rising sea surface temperatures impact this relationship? What phenomenon could occur as a result?
What three types of feeding strategies exist?
Filter feeding, or suspension feeding, deposit feeding, and carnivorous feeding.
Describe the zones of the reef slope and the characteristic coral types.
From the surface to a depth of 20 meters (66 feet), there is high-energy wave action and more than 60% of the surface light available. Massive branching corals and algae are found in this "buttress zone." Between the depths of 20 meters (66 feet) and 50 meters (164 feet), the light level drops to 20% of the surface light, and wave energy decreases. Massive head corals are common in this zone. Light levels drop to about 4% of surface light at 150 meters (492 feet). Wave energy is also minimal at this depth and delicate plate corals are common in this zone.
They have hundreds of tube feet that run along the undersides of their arms.
How do bat stars move?
By entrapping prey items in its stinging tentacles.
How does a sea anemone feed?
They have hard shells that prevent organisms from drying out.
In the spray zone, what is one common adaptation that marine organisms typically exhibit?
What conditions create ocean eutrophication (dead zones)?
Increased inorganic nutrient input, primarily nitrogen and phosphorus, from terrestrial sources (agriculture, urban run-off) stimulates coastal algal blooms. Eutrophication is caused by excess nutrient input into marine systems. Excessive algal growth pulls oxygen out of the water, producing low dissolved oxygen levels (less than 2.0 g/ml, hypoxia). When oxygen levels drop to 0 g/ml, a dead zone is created.
the productivity of the surface layer above it
(Intro) The amount of life on the ocean floor depends primarily on _________.
Is there scientific consensus about human-caused climate change? Explain.
Yes, there is scientific consensus about human-caused climate change due to emissions of greenhouse gases. This has been established by many scientists and major scientific organizations for over 20 years and has not changed.
The primary reason phytoplankton are "concerned" about buoyancy is that they _________.
cannot photosynthesize below the photic zone
It helps them to camouflage with the varied colors found in tidepools.
Part complete Why do different bat stars have colors that range from orange to mottled purple?
List the five parts of Earth's climate system.
The five parts of Earth's climate system are the atmosphere, hydrosphere, geosphere, biosphere and cryosphere.
What are the two food sources of deep-water nekton?
The food source for deep-water nekton comes from one of two places: detritus, dead and decaying organic matter and waste products that slowly settle through the water column from the highly productive surface waters, or each other. There are a number of predatory species.
byssus threads
What does a blue mussel (California mussel) use to attach to a rock?
two-spotted octopus
What is the common name of the octopus that is found in Southern California tidepools?
Waters of the continental shelf are generally _______. a. within the epipelagic zone b. within the abyssopelagic zone c. minimally productive waters d. highly productive waters e. within the neritic province
a, d, e
You are about to go out and harvest some Pismo clams. The environment you find them in will be _______.
benthic, littoral
Giant kelp is a member of the _________ group.
brown algae
The majority of our planet's biomass is represented by _________.
plankton
Why do fish with a swim bladder not have limits to the depth to which they can descend?
Animals with flexible air bladders, such as certain fish, do not suffer the threat of the swim bladder structurally collapsing because the bladder is flexible in contrast to the rigid cephalopod shell. These fish can also regulate the air pressure inside their air bladder.
Of the following statements about oceanic productivity, which is/are true? a. In tropical oceans, productivity is limited year-round by the lack of sunlight. b. In middle-latitude oceans, the spring bloom is limited by the lack of nutrients. c. In middle-latitude oceans, the fall bloom is limited by the lack of nutrients. d. In middle-latitude oceans, the spring bloom is limited by the lack of sunlight. e. In tropical oceans, productivity is limited year-round by the lack of nutrients. f. In middle-latitude oceans, the fall bloom is limited by the lack of sunlight.
b, e, f
Nektonic organisms in the photic zone often protect themselves from being seen from either above or below through _________.
countershading
Because of the scarcity of food in the deep-sea environment, many organisms rely on _________ as their principal source of food.
detritus
In the ongoing processes of photosynthesis, respiration, and decomposition in the ocean, all components are recycled except _________.
energy
Fossil evidence indicates that modern whales have evolved from ancestors similar to the _________.
hippopotamus
Describe the advantage that a top carnivore gains by eating from a food web as compared to a single food chain.
A top carnivore is more likely to survive eating from a food web because it has alternative foods to eat if its preferred food diminishes or disappears.
Explain why hydrozoans and scyphozoans (jellies) are classified as macroscopic forms of zooplankton. Why are they not considered nekton?
Hydrozoans and scyphozoans do not swim well. They propel themselves by way of muscular contraction. In contrast, nekton can swim well continuously.
What is the problem requiring osmotic regulation faced by hypotonic fish in the ocean? How have these animals adapted to meet this problem?
Hypotonic fish living in the ocean have body fluids with lower salinity and osmotic pressure than the salinity and osmotic pressure of the ocean water. As a result, their body fluids have a higher concentration of water than the surrounding ocean water, and they tend to lose water from their bodies by osmosis. To replace the lost water, they drink large quantities of ocean water, remove the salt through special cells, and thereby create a supply of replacement water. To conserve their body water, they excrete small volumes of very concentrated urine.
Recall our earlier discussions on paleoclimate; what are proxy data? List several examples. Why are such data necessary for paleoclimate studies?
A proxy is a substitution or an approximation for something else; specifically, proxy climate data is data that comes from natural recorders that serve as indirect evidence for climate in the past. Some examples include sea floor sediments, tree growth rings, trapped air bubbles in the annual layers of glacial ice, fossil pollen, coral reefs, cave deposits and historical documents. The proxy data is necessary due to a lack of direct measurements in the past, and serve to help understand Earth's past climate, which can then aid in gaining insight into Earth's current and future climate.
Discuss how sound reaches the inner ear of toothed whales.
All cetaceans have evolved structures that insulate the inner ear housing from the rest of the skull. In toothed whales, the inner ear is separated from the rest of the skull and surrounded by an extensive system of air sinuses (cavities). The sinuses are filled with an insulating emulsion of oil, mucous, and air, and are surrounded by fibrous connective tissue and venous networks. In many toothed whales, it is believed that sound is picked up by the thin, flaring jawbone and passed to the inner ear via the connecting oil-filled body.
What common characteristics do all organisms in the Class Mammalia share?
All organisms in the Class Mammalia (including marine mammals) share these common characteristics: 1. They are warm-blooded. 2. They breathe air. 3. They have hair (or fur) in at least some stage of their development. 4. They bear live young (except for the few egg-laying Australian mammals from the Subclass Prototheria, which includes the duck-billed platypus and the spiny anteater). 5. The females of each species have mammary glands, structures that give the class its name, that are used to produce milk for their young.
What are several benefits of schooling?
Although schooling is advantageous during spawning in that it ensures that males and females are in close proximity, most fish appear to school for the protection it provides from predators: • If members of a species form schools, they reduce the percentage of ocean volume in which a cruising predator might find one of their species. • Should a predator encounter a large school, it is less likely to consume the entire unit than if it encounters a small school or an individual. • The school may appear as a single large and dangerous opponent to the potential predator and prevent some attacks. • Predators may find the continually changing position and direction of the movement of fish within the school confusing, making attack particularly difficult for predators which can only attack one fish at a time.
Which adverse conditions of rocky intertidal zones seem to be most important in controlling the distribution of life?
An organism's success is closely tied to its ability to cope with the physical water conditions, the ocean floor, and other members of the biological community. One of the most prominent variables affecting species diversification of benthic organisms may be temperature. As well, the distribution of benthic biomass closely mirrors the distribution of photosynthetic productivity in the surface waters. This suggests that life on the ocean floor is very much dependent upon the primary photosynthetic productivity within the ocean's surface waters.
What are the three types of symbiosis, and how do they differ?
Commensalism occurs when a smaller or less-dominant participant benefits without harm to the host species that provides the commensal with food or protection. Mutualism occurs when both species benefit. Parasitism occurs when one organism (parasite) benefits at the expense of the host organism.
Describe the relationship between corals and algae and explain how corals benefit from having internal algae.
Corals and algae have a symbiotic relationship, meaning they are interdependent upon one another for survival. The algae are what give corals their varied colors as well. Corals benefit from these algae because corals generally live in nutrient-poor waters. The algae (zooxanthallae) provide the corals with a continual supply of food that they generate photosynthetically.
List several adaptations of deep-water nekton that allow them to survive in their environment.
Deep-water nekton have many special adaptations to allow them to be efficient at finding and collecting food. These include: • Good sensory devices such as long antennae or sensitive lateral lines that are used to detect the movement of other organisms within the water column. • Many species have large and sensitive eyes that enable them to see potential prey. To avoid becoming prey, most species are dark colored so that they blend in with the environment. • Other species are blind and rely on their other senses to obtain food. For instance, the sense of smell is well developed in some species, and that allows certain fish to track down prey items by following a scent trail. • Well over half of deep-sea fish have bioluminescence capabilities (the ability to biochemically produce light) by using specially designed structures or cells called photophores. • Large sharp teeth. • Expandable bodies. • Hinged jaws that can disarticulate. • Huge mouths in proportion to their body size.
List several examples of natural climate change. Do natural climate change mechanisms account for the recent climate changes that Earth is experiencing? Explain.
Examples of natural climate change include changes in solar energy, variations in Earth's orbit, volcanic eruptions and the movement of Earth's tectonic plates. Although natural factors have changed Earth's climate in the past and will continue to do so in the future, there is agreement among scientists that the observed warming in recent decades is occurring more quickly and with greater magnitude that can be explained by just natural factors; human-caused greenhouse gas emissions are a major factor in the recent warming.
What strategies exist (could be scientific or societal) to reduce future warming? What do you think you can do to contribute the reduction of future warming?
Global engineering, or manipulation of Earth's climate system, is one controversial way to try to reduce future warming. Methods include reducing the amount of sunlight reaching Earth and removing human-caused greenhouse gases from the atmosphere and dispose of them elsewhere. Global agreements, such as the Kyoto Protocol and the Paris Accord, are important to committing to long-term decreases in greenhouse gas emissions from countries. Continued research to understand the Earth's climate system will also allow further diagnosis of the issues at hand in order to properly prepare possible solutions. Your opinions on what you can do to help are all up to you!
Describe several changes that are already occurring in the oceans because of global warming.
Global sea surface temperatures have risen by about 0.6°C since 1970. There could be links to increased hurricane activity since 1970 due to this (recall that warm SSTs are the major ingredient for tropical cyclone formation from Chapter 6. The global thermohaline circulation (recall from Chapter 7) has been impacted due to the fact that it is density-driven, and waters being warmer lead to different density gradients across the oceans. Specifically, the sinking of the North Atlantic water has been compromised. Polar ice has also melted at an accelerated rate, which can also impact the thermohaline circulation due to fresher water (recall from Chapter 5 that sea ice has lower salinity) and further density changes. This ice melt as well as thermal expansion then lead to sea level rise. There are also many impacts biologically—for example, due to ocean acidification caused by increased oceanic carbon dioxide concentrations, this weakens the shells of many marine organisms.
Describe the characteristics of hydrothermal vents.
Hydrothermal vents occur along the crest of the mid-ocean ridge where the lithosphere is thin and volcanic activity is common. They exist in complete darkness at water depths ranging from 1525 meters (5000 feet) to 3600 meters (11,800 feet). Hydrothermal vents emit hot water up to 350°C (662°F) that is so rich in metal sulfides that it colors the water black, giving these features the name "black smokers." The chimneys associated with these vents were first observed in 1979 and are composed primarily of copper sulfides, zinc sulfides, and silver sulfides. Hydrothermal vents are often colonized by unusual life forms that comprise the hydrothermal vent biocommunities.
spray zone, upper intertidal zone, middle intertidal zone, lower intertidal zone
In a tidepools area such as that shown in the video, what is the correct order of intertidal zones, going from the base of the coastal cliffs into deeper water?
b, d, e
Of the following statements about benthic communities along sediment-covered shores, which is/are true? Choose all that apply. a. Nearly all the organisms that inhabit sediment-covered shores are sessile epifauna. b. Coarse sandy beaches usually have the same tidal zonations as rocky shores. c. The most stable sediment-covered shores have the largest grain sizes. d. Large numbers of organisms can generally be found buried in sandy shores. e. Gently sloping beaches with finer sediment show less distinct intertidal zonation as compared to coarser beaches.
What are the major differences between the conditions and biocommunities of the hydrothermal vents and the cold seeps?
In hydrothermal vent fields, water temperatures range as high as 12°C (54°F), while the temperatures at the cold water seeps are near ambient values of local water conditions (usually just a few degrees above freezing). Hydrothermal vents are found only in association with springs at the base of the Florida Escarpment, at hydrocarbon seeps, and at subduction zones where trench sediments have been folded. Additionally, the producers at hydrothermal vents are exclusively sulfur-oxidizing bacteria, while at the cold seeps, sulfur- and methane-oxidizing bacteria are important.
They are well camouflaged so that they can blend in and hide from predators during low tide.
In the lower intertidal zone, what is one common adaptation that marine organisms typically exhibit?
Describe the process by which the sperm whale produces echolocation clicks.
In the sperm whale's large head, air is forced from the trachea through the nasal passages and past the lips of the "monkey's muzzle." Contractions of muscles in these structures produce sound that travels toward the head and reflects off the front of the skull, which is bowl-shaped and resembles a radar dish. The sound passes through an organ called the spermaceti organ, in which sound is concentrated by forming various shapes and sizes of lenses. In essence, the organ acts as an acoustical lens that focuses the sound.
Describe marine mammals within the Order Carnivora, including their adaptations for living in the marine environment.
Marine mammals within the Order Carnivora include sea otters, polar bears, and the pinnipeds (walruses, seals, sea lions, and fur seals), all of which have prominent canine teeth. Sea otters have dense fur that insulates them from the cold water in which they live. Polar bears have fur with hollow hair shafts for insulation and webbed feet for swimming. Pinnipeds have sensitive whiskers and prominent skin-covered flippers that are used to propel them through the water. •
Describe the marine mammals within the Order Sirenia, including their distinguishing characteristics.
Marine representatives of the Order Sirenia include the manatees and dugongs, which are collectively referred to as "sea cows." The manatees are concentrated in coastal areas of the tropical Atlantic Ocean, while dugongs populate the tropical regions of the Indian and Western Pacific Oceans. Both of these animals have a paddle-like tail and rounded front flippers. The land-dwelling ancestors of the sirenians were elephant-like, and extant sirenians today retain some of these unique characteristics, such as a large body size and the presence of toenails in manatees. The sirenians have sparse hairs covering their body but concentrated around the mouth.
Describe changes in the physical environment that occur as one moves from the shoreline to the deep-ocean floor.
Moving from the shore along the ocean floor to the deep-ocean basins, the physical environment changes significantly (available light, water temperature, pressure, salinity, etc.). The energy level decreases below wave base (variable, but generally shallow), light decreases gradually and is absent below 1000 meters (3300 feet), and the temperature drops to a fairly uniform 3°C (37.4°F). Pressure increases by 1 atmosphere (14.7 pounds per square inch) with each increase in depth of 10 meters (33 feet). Fine oozes and clays in the deep-ocean basins replace coarse sediment near shore.
One of the most noticeable features of the middle tide zone's long, rocky coasts is a mussel bed. Describe general characteristics of mussels and include a discussion of other organisms that are associated with mussels.
Mussel beds of the genera Mytilis and Modiolus attach to the middle tide zone rocks by secreting hair-like byssal threads. The base of the mussel bed is often very abrupt. A common and visible member of the mussel bed is the goose barnacle, Pollicipes. The mussels are preyed upon by the sea stars, Pisaster and Asterias. Less visible algae, snails, hydroids, worms, clams, and crustaceans are also found in the mussel beds.
blend in with the color and texture of the surrounding environment
One of the main ways in which octopuses avoid predators is to __________.
Besides the "dead whale hypothesis", what other ideas have been suggested to explain how organisms from hydrothermal vent biocommunities populate new vent sites?
Other researchers believe that deep ocean currents are strong enough to transport drifting larvae to new sites. Still others have suggested that the rift valleys of mid-ocean ridges may have acted as passageways along which drifting larvae of hydrothermal vent organisms have traversed to inhabit new vent fields. By whatever means these organisms travel, evidence indicates that they are able to colonize new hydrothermal vents soon after the vents are created.
Describe the physical factors related to zones of the reef slope.
Physical factors related to the zonation of coral reefs usually include wave energy, salinity, water depth, and temperature. Coral is usually massive in high-energy, near-surface portions of the reef. With increasing depth, wave energy and light energy decrease, producing corals that are more delicate. Corals will not survive at all below about 150 meters (492 feet).
How can dolphins be differentiated from porpoises?
Porpoises are generally smaller than dolphins, and they have a more "stout" (bulky and robust) body shape compared to the elongated and streamlined dolphin body. Generally, porpoises have a blunt snout (called a rostrum) in contrast to dolphins, which have a longer rostrum. Porpoises have a smaller and more triangular (or, on one species, no) dorsal fin, whereas the dolphin's dorsal fin is sickle-shaped or falcate. The best way to tell the two apart is by their teeth. Dolphin teeth end in points in contrast to porpoise teeth that are blunt or flat (shovel-shaped) and resemble human incisors.
How can true seals be differentiated from the eared seals (sea lions and fur seals)?
Seals, also called earless seals or true seals, differ from sea lions and fur seals, also called eared seals, by the following distinguishing characteristics: • Seals lack the prominent earflap that is specific to sea lions and fur. • Seals have smaller and less prominent front flippers (called fore flippers) than sea lions and fur seals. • Seals have prominent claws that extend from their flippers that sea lions and fur seals lack. • Seals have a different hip structure than sea lions and fur seals. Seals cannot move their rear flippers underneath their bodies as sea lions and fur seals can. • Seals do not walk on land very well, and can only slither along on their bellies (like a caterpillar); sea lions and fur seals use their rear flippers under their bodies and their large front flippers to walk easily on land; they can even ascend steep slopes, climb stairs, and do other acrobatic tricks. • Seals propel themselves through the water by a back-and-forth motion of the rear flippers (similar to a wagging tail) in contrast to sea lions and fur seals that swim by flapping their large front flippers.
What are some of the adverse conditions of rocky intertidal zones? What are some organisms' adaptations to those adverse conditions?
See Table 15.1 for a list of adverse conditions in the intertidal zone and some adaptations of organisms that live there.
Sketch a rocky-shore intertidal region. Label each zone and include characteristic organisms that are typically found there. Upload your well-labeled sketch.
Student drawings will vary but should resemble Figure 15.2a.
Sketch a sand-covered intertidal region. Label each zone and include characteristic organisms that are typically found there. Upload your well-labeled sketch.
Student drawings will vary but should resemble Figure 15.8.
Describe the differences between cetaceans of the Suborder Odontoceti (toothed whales) from those of the Suborder Mysticeti (baleen whales). Be sure to include examples from each suborder.
Suborder Odontoceti (toothed whales) have prominent teeth and includes killer whales, sperm whales, porpoises, and dolphins. Suborder Mysticeti (baleen whales) includes the great whales (the largest whales) such as the blue whale, the finback whale, humpback whale, and the gray whale. The baleen whales have no teeth. Instead they have baleen, plates of fibrous material that hang from the whale's upper jaw on the inside of their mouths. Toothed whales have one external nasal opening (blowhole) in contrast to the baleen whales that have two external openings.
What is the "dead whale hypothesis"?
The "dead whale hypothesis" suggests that when large animals such as whales die and sink to the deep ocean floor, they may provide a temporary stepping-stone for organisms that inhabit the hydrothermal vent fields separated by large distances. Decomposition of a whale carcass provides an energy source for these organisms that breed and release their larvae, some of which make it to the next hydrothermal vent site.
Why did the International Whaling Commission (IWC) invoke a ban on commercial whaling?
The International Whaling Commission (IWC) was established by the UN in 1946 to manage whale populations and prevent further depletion of whale populations which are at critically low levels.
Discuss the dominant species of kelp, their epifauna, and animals that feed on kelp in Pacific coast kelp forests.
The dominant species of kelp found in Pacific coast kelp forests are Macrocystis (giant brown bladder kelp) and Nereocystis. Smaller varieties of red and brown algae grow on the larger varieties along with hydroids and bryozoans. Nudibranchs feed on hydroids and bryozoans. Very few animals feed directly on living kelp plants. The sea hare, Aplaysia, and sea urchins do feed on living kelp.
Describe the mechanism by which baleen whales feed.
The main obstacle that baleen whales face in obtaining food is how to concentrate their small prey items and how to separate these items from seawater. To accomplish these tasks, baleen whales use their rows of fibrous baleen in their mouths that hang from their upper jaw and act as an ideal strainer. To feed, baleen whales fill their mouths with water that includes their prey, allowing their pleated lower jaw to balloon in size. The whales force the water out between the baleen slats, trapping small fish, krill, and other plankton on the inside of their mouths. Mostly, baleen whales feed at or near the surface, sometimes working cooperatively in large groups. However, the gray whale has short baleen slats and feeds by filtering sediment from the shallow bottom of its North Pacific and Arctic feeding grounds, straining out a diet of benthic organisms.
What is the major similarity between the biocommunities of the hydrothermal vents and the cold seeps?
The overriding similarity of the communities found at the hydrothermal vents and cold water seeps is that the organisms are much larger than typical deep-sea species because of the large food supply that is locally available by chemosynthetic bacteria.
What three ways exist to legally hunt whales? Which countries are doing each?
The three conditions under which whaling may continue are: a. Whaling by objection: countries which continue to hunt under objection to IWC ban - Norway b. Scientific whaling: Whaling for scientific research purposes; note that whale products collected in this manner may not be sold for profit - Japan c. Whaling by aboriginal cultures for subsistence: whaling by native cultures where there is a cultural tradition of subsistence whaling - Greenland, Russia, United States, Saint Vincent and the Grenadines.
How does the diversity of species on sediment-covered shores compare with that of the rocky shore? Suggest at least one reason why this occurs.
There are more species living on rocky shores than sediment-covered shores. A possible reason for this is that there are more environmental niches on rocky shores than on sediment-covered shores. An environment that has many niches creates conditions that produce high species diversity.
Besides schooling and symbiosis, what other adaptations do pelagic animals possess to avoid being prey?
These adaptations include using speed, secreting poisons, and mimicking other poisonous or distasteful species. Some species use transparency, camouflage, or countershading.
Describe how sandy and muddy shores differ in terms of energy level, particle size, sediment stability, and oxygen content.
This information is summarized in the table below: a. Sandy Shores b. Muddy Shores Energy Level a. High b. Low Particle Size a. Medium- to Coarse-Grained b. Fine-Grained Sediment Stability a. Low b. High Oxygen Content a. High b. Low Sediment salinity increases and permeability (the ability of a substance to pass fluid) decreases with decreased particle size. The higher sediment stability of mud flats results from the high cohesive attraction between clay particles and the lower energy longshore current in mud flat regions. The fact that sand-sized particles are rounder and clay-sized particles are flat results in the higher permeability of muddy sediment. Large amounts of organic material must be anaerobically decomposed in these deposits. This often results in sediment from mad flats having a black color and a strong hydrogen sulfide odor.
shrimp
To which of the following animals are acorn barnacles closely related?
They eat detritus, dead and decaying organic material, and seaweed.
What do bat stars eat?
tiny microscopic marine organisms that live in seawater
What do mussels, gooseneck barnacles, and acorn barnacles all eat?
a strong stalk
What does a gooseneck barnacle use to attach to a rock?
middle intertidal
What intertidal zone do sea anemones typically inhabit?
a harmless flower
What is a sea anemone -- a vicious predatory toxic animal -- carefully disguised as?
They must be adapted for being out of water for extended periods of time.
What is an adaptation for organisms living in the upper intertidal zone?
Shells and rocks prevent the sea anemone from drying out during low tide.
What is the purpose of the shells and rocks that are attached to a sea anemone's body?
It activates stinging barbs that inject neurotoxin into your skin.
When you visit a tidepool and put your finger into a sea anemone, it grabs onto your finger. What is really happening?
a, c, d, e
Which of the following statements about the characteristics of the deep-ocean floor are true? Choose all that apply. a. Even in tropical latitudes, water temperatures in the deep ocean are near freezing. b. There are extremely variable conditions on the deep-ocean floor. c. Only about 1% to 3% of the food produced in the euphotic zone reaches the deep-ocean floor. d. Species diversity in the deep ocean can rival that of tropical rain forests. e. Deep-ocean communities exist in the bathyal, abyssal, and hadal zones.
a, b, e
Which of the following statements about tropical reef-building corals are true? Choose all that apply. a. The biomass of coral reefs is composed mostly of algae. b. Coral reefs require moderate to strong wave action or current flow. c. Coral reefs need shallow, highly turbid waters to survive. d. Most coral reefs require nutrient-rich waters to support the needs of the zooxanthellae. e. Reef corals need warm, tropical waters to survive.
Where does the food come from to supply organisms living on the deep-ocean floor? How does this affect benthic biomass?
With the exception of chemosynthetic productivity that occurs around hydrothermal vents, all deep-ocean floor organisms receive their food from the surface waters above. Low food availability, and not low temperature, low oxygen concentration, or high pressure, limits deep-sea benthic biomass.
too much freshwater is flowing in from the river closer to shore
You are vacationing on a beautiful tropical island and want to see a coral reef. Your boat travels down a river estuary and then travels a considerable distance along the coast before any coral is seen. The reason you had to travel so far to see coral is probably that _________.
In which intertidal zone of a steeply sloping, coarse-sand beach would you find each of the following organisms: clams, beach hoppers, ghost shrimp, sand crabs, and heart urchins?
• Clams: Low through middle tide zones • Beach hoppers: Supratidal zone • Ghost shrimp: Middle and high tide zones • Sand crabs: Low and middle tide zones • Heart urchins: low tide zone
In which intertidal zone of a rocky shore would you typically find each of the following organisms: sea anemones, sea lettuce, rock louse, abalones, brittle stars, and buckshot barnacles?
• Sea anemones: Middle Tide Zone • Sea lettuce: Middle Tide Zone • Rock louse: Spray Zone • Abalones: Middle Tide Zone • Brittle Stars: Low Tide Zone • Buckshot barnacles: High Tide Zone
What does a dolphin's melon do?
The melon focuses sound waves during emission.
The color of light most readily absorbed by water is _________.
red
Explain similarities and differences among the following: red tides, and harmful algal blooms.
A red tide is a proliferation of dinoflagellates to such an extent that they color the surface waters red. Red tides are specific to certain species of dinoflagellates. Because these dinoflagellates secrete potent biotoxins, these red tides are more correctly called harmful algal blooms. Note that not all algae will cause a harmful algal bloom because not all algae secrete potent biotoxins.
For the following marine organisms, determine if they are plankton, nekton, or benthos: a) sharks, b) octopuses, c) clams, d) diatoms, e) corals, f) crabs, g) giant kelps, h) jellies, i) dolphins.
A. Sharks - nekton B. Octopuses - nekton C. Clams - benthos D. Diatoms - plankton E. Corals - benthos F. Crabs - benthos G. Giant kelps - plankton H. Jellies - plankton I. Dolphins - nekton
List the three major domains of life. Describe the fundamental criteria used in assigning organisms to these divisions.
All living organisms can be divided into one of three major domains (branches) of life: Archaea, Bacteria, and Eukarya. A. Archaea is a group of simple microscopic bacteria-like organisms that are believed to be the closest ancestors of primitive cells. They are often found living in extreme environmental conditions (temperature, pressure, salinity, etc.) that may be similar to the conditions of the primitive Earth. This group includes the methane producers and sulfur-oxidizing organisms found in hydrothermal vents. B. Bacteria include simple single-celled organisms that have cell walls and lack a defined nucleus. Members of this group include cyanobacteria (blue-green algae), purple bacteria, green non-sulfur bacteria, and many of the disease-causing bacteria. C. Eukarya contain all organisms containing cells with membrane-bound organelles and a nucleus defined by a membrane. Protists, fungi, plants, and animals are all members of this domain.
What are thought to be the ancestors of the three domains of life?
All organisms are thought to share one common ancestor. This idea is called universal common ancestry. These ancestors are thought to have been a community of early primitive cells, some of which engulfed neighbors, acquiring new genetic coding.
Discuss chemosynthesis as a method of primary productivity. How does it differ from photosynthesis?
Chemosynthesis differs from photosynthesis in that the energy that goes into the product of the reaction comes from the release of energy from chemical bonds rather than solar radiation. Chemosynthesis can occur in the absence of sunlight such as in communities associated with hydrothermal vents along the mid-ocean ridge. Here the energy of hydrogen sulfide bonds (H₂S) is released through oxidation to free (S) or sulfate (SO₄). The bacteria that serve as food for filter-feeding benthos, and the chemosynthetic worms associated with these vents, produce their own food through chemosynthesis.
Productivity in specific regions of tropical oceans is not uniformly low. What factors contribute to the higher productivity with coastal upwelling?
Coastal upwelling: Where the prevailing winds blow toward the equator and along the western continental margins, surface waters are driven away from the coast. The displaced water is replaced by nutrient-rich water surfacing from depths of 200 to 900 meters (660 to 2950 feet). This nutrient-rich upwelling promotes high primary productivity in these areas, in turn, it supports large fisheries. In the Pacific, such conditions exist along the southern coast of California and the southwestern coast of Peru; in the Atlantic, they exist along the northwestern coast of Morocco and the southwestern coast of Africa.
Describe the color difference between coastal waters and less-productive open-ocean water and explain why each has the color that it does.
Coastal waters tend to be yellow-green in color because of the presence of turbidity from continental runoff and because of the microscopic organisms that thrive in this high-nutrient environment. Open ocean water lacks this turbidity and concentrated abundance of nutrients and photosynthetic organisms and tends to be indigo blue. In addition, a physical property of deep water is that it scatters incoming solar radiation preferentially in the blue portion of the electromagnetic spectrum, making the water appear blue.
Discuss the characteristics of the coastal ocean where unusually high concentrations of marine life are found.
Conditions that result in unusually high concentrations of marine life in some coastal regions are the result of coastal upwelling. Particularly where the surface water is moved offshore by Ekman transport, water from beneath the photosynthetic zone will rise to replace it. Since there is no plant or algal life growing in these deeper waters, they are rich in plant and algal nutrients and serve to continuously supply nutrients to the sunlit surface waters.
An important variable in determining the distribution of life in the oceans is the availability of nutrients. How are the following variables related: proximity to the continents, availability of nutrients, and the concentration of life in the oceans?
Continents are a source of nutrients due to runoff from the land, specifically nitrates and phosphates, which are essential for phytoplankton. The greatest concentrations of marine organisms are proximal to the continents because the continents are a major source of nutrients. Phytoplankton use the nutrients to produce carbohydrates, fats, and proteins that make up the base of the food web.
Productivity in specific regions of tropical oceans is not uniformly low. What factors contribute to the higher productivity in coral reefs?
Coral reefs: Organisms that comprise and live among coral reefs are superbly adapted to low-nutrient conditions, in a similar manner to how some terrestrial organisms are adapted to a desert existence. Symbiotic algae living within the tissues of coral and other species allow coral reefs to be highly productive ecosystems. Additionally, coral reefs tend to hold and concentrate the low levels of nutrients in the ecosystem.
Productivity in specific regions of tropical oceans is not uniformly low. What factors contribute to the higher productivity with equatorial upwelling?
Equatorial upwelling: Where the trade winds drive westerly equatorial currents on either side of the equator, surface water diverges as a result of Ekman transport. The surface water that moves toward higher latitudes is replaced by nutrient-rich water that surfaces from depths of 200 meters (660 feet). Equatorial upwelling is best developed in the eastern Pacific Ocean.
Describe the three zones based on the availability of sunlight. Which one is where most marine life exists?
Euphotic zone - extends from surface to depth where photosynthesis can still happen, rarely deeper than 100 meters (330 feet) Disphotic zone - below the euphotic zone, has small but detectable amounts of light, extends to about 1000 meters (3300 feet) Aphotic zone - has no light, generally found deeper than 1000 meters (3300 feet) Most marine life exists in the euphotic zone.
Another important determinant of productivity is the availability of solar radiation. Why is biological productivity relatively low in the tropical open ocean, where the penetration of sunlight is greatest?
Even though there is a thicker column of sunlit water in the open ocean far from the continents than in the turbid water near their shores, photosynthesis is greatly restricted in the clear open ocean water by the lack of nutrients in surface waters.
Of the following types of seafood on a menu, which is the best choice for supporting sustainable fisheries: a) farmed salmon; b) monkfish; c) orange roughy; d) Atlantic cod; or e) Pacific halibut?
Farmed salmon is the best choice for supporting a sustainable fishery.
What is the problem requiring osmotic regulation faced by hypotonic fish in the ocean? How have these animals adapted to meet this problem?
In the ocean hypotonic fish are less salty than the water around them, because of this they lose alot of water through osmosis. If they continue to lose water through osmosis they will die. To counteract this problem they drink lots of water to make up for the water lost, their cells excrete the salt from the water they drink, and they yurinate small amounts of highly concentrated waste to conserve water.
List differences between cold- and warm-water species in the marine environment.
In warmer waters, floating organisms are physically smaller than organisms in colder waters. This is probably related to the lower viscosity and density of seawater in low-latitude waters. Smaller tropical species can expose more surface area per unit of body mass. Warm-water species are characterized by ornate appendages/plumage to increase surface area. The extra ornamentation is notably absent in cold-water species (refer to Figures 12.7 and 12.8). Warmer temperatures increase biological activity rates that more than double with an increase of 10°C (18°F). Tropical organisms apparently grow faster, have a shorter life expectancy, and reproduce earlier and more frequently than their cold-water counterparts. Tropical populations have increased species diversity in comparison to cooler water marine populations. However, total planktonic biomass in colder, higher-latitude environments is much greater than at tropical latitudes.
What characteristics should be included in a good working definition of life?
Life consumes energy from its environment and needs water or some other solvent to survive. There should exist a membrane to distinguish a living thing from its environment. It should be adaptable to its environment, able to evolve, and able to reproduce
Describe the yearly productivity pattern in polar oceans, including the main factor that limits productivity in polar oceans.
Many parts of the polar ocean experience darkness, and hence no photosynthetic phytoplankton, for about 3 months of the year. When sunlight is able to penetrate the ocean deep enough, plankton will start to develop and other organisms will feed on them. The Antarctic has somewhat greater productivity than the Arctic because North Atlantic Deep Water upwells near Antarctica with its high nutrient concentration. The main limiting productivity factor in polar oceans is the availability of solar energy.
Name and describe the different types of fins that fish exhibit.
Most active swimming fish have two sets of paired fins used in maneuvers such as turning, braking, and balancing. These are the pelvic fins and pectoral fins (refer to Figure 14.9). When not in use, these fins can be folded against the body. Vertical fins, both dorsal and anal, serve primarily as stabilizers. The fin that provides most of the thrust for forward motion in high-speed fish is the caudal fin (tail fin).
Are most fast-swimming fish cold-blooded or warm-blooded? What advantage does this provide?
Most fast-swimming fish, such as mackerel, sharks, and tuna, are warm-blooded (homeothermic). The higher body temperature of homeothermic cruisers increases the power output of their muscle tissue. Therefore they can move faster more immediately than cold-blooded fish. These homeothermic fish conserve the heat needed to maintain body temperature by a modification of their circulatory system: they have cutaneous veins and arteries running along the sides of their body.
How many total species have been cataloged on Earth? How many marine species exist (both number and percentage of total)? Of marine species, how many are benthic versus pelagic?
Of the more than 1.8 million known species of organisms that live on Earth, only about 14% (250,000) inhabit the oceans. Of the marine species, 98% are benthic and only about 2% (about 5,000 species) are pelagic.
How does water temperature affect the water's ability to hold gases? How do marine organisms extract the dissolved oxygen from seawater?
Reducing the temperature of seawater increases its capacity to hold gases in solution (cold water holds more dissolved gas in solution). To extract dissolved oxygen from seawater, most marine animals have specially designed fibrous respiratory organs called gills that serve to exchange oxygen and carbon dioxide directly with seawater.
Explain how environmental variability affects the number of species present.
On land, there are many different habitats, or ecological niches, for species to inhabit. Each species may uniquely adapt itself for a particular environment. More habitats, or niches, means more species may be present. In the ocean, the benthic environment has many habitats, or niches, for organisms. Therefore the benthic environment can support more species due to more niches, or specialized habitats, for a wider variety of organisms than the fairly uniform open waters of the pelagic environment.
Discuss some adaptations other than size that organisms use to increase their resistance to sinking.
Organisms use several strategies to prevent sinking that are not related to size. Organisms can increase their drag in the water using adaptive body shapes that increase frictional resistance. Organisms can also decrease their density relative to seawater. This is accomplished in several ways. The Portuguese Man-O-War has a gas bladder that it uses as a flotation device. Other organisms have evolved "sail-like" structures such as appendages that are perpendicular to the water surface. Pelagic large macroalgae have gas-filled bladders (pneumocysts) that keep these organisms near the surface where light is available for photosynthesis. The majority of bony fishes have internal gas bladders that they use to adjust water column position. Other organisms increase fat and/or oil concentrations in their bodies to decrease their density. Sharks have large fatty livers that increase their buoyancy. Some organisms, squid and dinoflagellates for example, exchange heavier ions (such as sodium, molecular weight 23) for lighter ions (ammonium, molecular weight 18). The exchanged ions have the same electrical charge so that salt and water balance is not affected.
Define overfishing. When a species is overfished, what changes are there in the standing stock, the size of individuals in the remaining fish population, and the maximum sustainable yield?
Overfishing happens when fish are removed from the population so quickly that the remaining population is not yet sexually mature enough to reproduce, resulting in a decline in the fish population and the general size of the fish in that population. The maximum sustainable yield will be significantly reduced as well.
Define overfishing. When a species is overfished, what changes are there in the standing stock, the size of individuals in the remaining fish population, and the maximum sustainable yield?
Overfishing is when a population of fish are fished so much that the remainder of their population are immature fish incapable of reproducing. This means that the standing stock has been depleted, the remaining fish are too small to legally catch, and the maximum sustainable yield has gone down as the reproduction rate of the fish has been significantly decreased.
List the subdivisions of plankton and benthos, and the criteria used for assigning individual species to each.
Plankton Phytoplankton - photosynthetic, plant-like plankton Zooplankton - heterotrophic, animal-like plankton Bacterioplankton - unicellular, bacteria-like plankton Macroplankton - large plankton such as jellyfish Microplankton - small plankton that can be caught in a fine-meshed silk net Picoplankton - plankton that are smaller than 2 μm in diameter Holoplankton - organisms that spend their entire life cycle as plankton Meroplankton - organisms that spend only the larval stage as plankton and then become either nekton or benthos.
Describe the lifestyles of plankton, nekton, and benthos.
Plankton are organisms that cannot swim against a current and drift in the ocean. Wind and water currents determine their movement. Nekton are organisms that are active swimmers such as fish and marine mammals. They can determine their position in the water column and on the ocean's surface because of their larger size and increased mobility (efficient locomotion). Benthos are organisms that live on the ocean's bottom.
What factors account for the fact that most marine species inhabit the benthic environment?
There are great numbers of benthic environments that create assorted habitats for different organisms to inhabit. The pelagic environment is far more uniform.
Why is it true that plankton account for a much larger percentage of the ocean's biomass than benthos and nekton?
Since larger animals eat smaller animals and only a small percentage of the energy (10%) obtained by one population is passed on to the population that feeds on it, the percentage of ocean biomass represented by populations of large animals is necessarily less than that represented by smaller organisms. Because phytoplankton either directly or indirectly provide essentially all of the energy for all the oceans' populations, they therefore must also represent by far the largest part of the biomass in the ocean.
Describe trends that occur in number of individuals, total biomass, and organism size at successive trophic levels going up a biomass pyramid.
The number of individuals is greatest at the bottom of a biomass pyramid. Total biomass decreases the higher up they are found in the pyramid but organism size increases.
Of the following locations, which is/are exceptions to the general rule that productivity is steady and low in tropical regions? a. coral reefs b. in the deep ocean, far from land c. coastal upwelling d. equitorial upwelling e. anywhere there is a strong thermocline
a, c, d
Discuss why the rigid gas chamber in cephalopods limits the depth to which they can descend.
The cephalopods Nautilus, Sepia, and Spirula (see Figure 14.1) all have rigid chambered shells that contain gas at a pressure of 1 atmosphere (14.7 pounds per square inch). The maximum depth to which they can descend depends on the strength of the chambered shell. The shells of these cephalopods will collapse when the external pressure exceeds the strength of their shell. For example, the Nautilus will implode at a depth of about 500 meters (1640 feet).
How does the depth of the deep scattering layer vary over the course of a day? Why does it do this? Which organisms comprise the DSL?
The deep scattering layer is a sonar-reflecting surface that undergoes a daily vertical migration in response to light intensity between the depths of 100 to 200 meters (330 to 660 feet) about midnight, and 900 meters (2950 feet) at noon. It is possible that the organisms moving in response to the changes in light intensity are small crustaceans such as copepods or euphausids. Contributing a great deal to the reflecting of sound waves may be small lantern fish that feed on these crustaceans. One reason for this is that lantern fish have swim bladders that help them maintain neutral buoyancy in the water column. These swim bladders contain gas that has a very low density in comparison to seawater and is quite effective at sound reflection.
What is the average efficiency of energy transfer between trophic levels? Use this efficiency to determine how much phytoplankton mass is required to add 1 gram of new mass to a killer whale, which is a fourth-level carnivore.
The efficiency of energy transfer between trophic levels averages 10% (0.10). To add 1 gram of new mass to a killer whale at the fourth trophic level requires: 1÷ 0.10 ÷ 0.10 ÷ 0.10 ÷ 0.10 = 10,000 grams of phytoplankton mass
Why is the productivity in tropical oceans uniformly low year-round?
The main limiting productivity factor in tropical oceans is the availability of nutrients.
Explain why the two curves in Figure 12.26 have the shape that they do (for example, why the oxygen minimum layer exists, and why it coincides with the nutrient maximum).
The oxygen minimum layer coincides with the nutrient maximum because they are at a region where no photosynthetic (oxygen-producing) organisms live but there is an abundance of dead organic tissue descending from the upper waters. Oxygen increases again with depth as it is replenished via an influx of cold polar waters. Nutrient levels remain high with depth due to the abundance of organisms.
How does the flow of energy through the biotic community differ from the manner in which mass is moved through the ecosystem?
The unidirectional flow of energy prevents the recycling of energy within the system once it has been released from its chemical state. Mass moved through the ecosystem is different because the energy represented by the mass of organic matter that is decomposed to inorganic forms is recyclable through the biological uptake of photosynthesis and chemosynthesis.
Name and describe the different types of fins that fish exhibit.
There are 5 different kinds of fins. a. Rounded Fins: flexible fins found on slower fish and are useful for accelerating and maneuvering at slow speeds b. Truncate Fins: semi-flexible fins found on faster moving fish and are useful for better propulsion and for maneuvering c. Forked Fins: semi-flexible fins found on faster moving fish and are useful for better propulsion and for maneuvering d. Lunate Fins: non-flexable fins found on fast-cruising fish and are extremly good for propultion but useless for manuverability e. Heteroceral Fins: asymetrical (non-symetrical) fins found on sharks that are used to compensate for the sharks negative bouyancy and provide lift. They are not very good for maneuverability.
What are the five basic shapes of caudal fins, and what are their uses?
There are five basic shapes of caudal fins, as illustrated in Figure 14.10 and keyed by letter to the following description: a. The rounded fin is flexible and useful in accelerating and maneuvering at slow speeds. b. and c. The somewhat flexible truncate tail (B) and forked tail (C) are found on faster fish and still may be used for maneuvering. d. The lunate caudal fin is found on the fast-cruising fish such as tuna, marlin, and swordfish; it is very rigid and useless for maneuvering, but very efficient at propelling the fish. e. The heterocercal fin is asymmetrical, with most of its mass and surface in the upper lobe. The heterocercal fin produces a significant lift as it is moved from side to side and is common in fish with no swim bladder such as sharks.
Describe the yearly productivity pattern in middle-latitude oceans.
There are pronounced seasonal variations at temperate latitudes, and this variation produces a more complex pattern of productivity than in either polar or tropical regions. During the winter, thermal stratification may be minimal, and the surface waters are rich in nutrients as a result of mixing between the deep- and surface-water layers. Productivity is low, however, due to the low angle at which the Sun's rays strike the ocean surface. Very little solar radiation penetrates the water column, producing a low photosynthetic rate. As the Sun rises higher in the sky during the spring, sufficient sunlight penetrates the water column, producing a spring phytoplankton bloom. The increased availability of solar radiation also results in the development of a thermocline that prevents the continued supply of nutrients from deep water, and productivity decreases until fall cooling begins to weaken the thermocline. Mixing again occurs, and a smaller fall phytoplankton bloom occurs. It is soon limited by decreased amounts of solar radiation because the Sun is lower in the sky and the day length decreases.
What is/are the limiting factor(s) for the spring phytoplankton bloom at temperate latitudes? What is/are the limiting factor(s) for the fall phytoplankton bloom?
There is a high level of spring productivity that is limited by a reduced supply of nutrients, and a fall increase in productivity that comes to an end because of the lack of solar radiation.
How do gray whales collect and eat such small organisms?
They use their baleen to filter prey items from their environment.
Describe three examples of unintended consequences that have occurred in marine ecosystems when top predators are removed.
Top predators keep smaller, lower trophic level fish populations from overrunning ocean ecosystems to the point of destruction. Top predators also keep marine ecosystems healthy because they will prey first on the sick, lame, and old members of lower trophic levels. A coral reef ecosystem may be affected if top carnivores are removed because smaller fish may proliferate and allow for an increase in algae on the corals, which in turn suppresses the coral growth.
Of the following characteristics, which apply to a planktonic organism that photosynthesizes? a. Classified as phytoplankton b. Classified as zooplankton c. A type of heterotrophic organism d. A type of autotrophic organism e. Living within the euphotic zone f. Living in the aphotic zone
a, d, e
List the five kingdoms of organisms. Describe the fundamental criteria used in assigning organisms to these divisions.
Within the three domains of living organisms, five distinct kingdoms of life are recognized. These kingdoms are separated using the level of cellular complexity and cellular structures shared by the members of the kingdoms: Monera, Protista (Protoctista), Fungi, Plantae, and Animalia. A. Kingdom Monera includes all of the simple, single-celled microscopic organisms in the domains Archaea and Bacteria. These organisms have cells that lack specialized organelles (compartments) delineated by membranes, and no membrane-bound organelles. B. Kingdom Protista (Protoctista) includes all of the simple unicellular organisms with membrane-bound nuclei and organelles, and many multicellular, photosynthetic organisms that have an independent unicellular phase in the life cycle (macroalgae). C. Kingdom Fungi includes complex multicellular heterotrophic organisms that have cell walls including fungi and molds. D. Kingdom Plantae includes complex multicellular photosynthetic organisms that have cells with cell walls; plants. E. Kingdom Animalia includes complex multicellular heterotrophic organisms that lack cells walls (plasma membranes only); animals.
Of the following statements about marine fisheries, which is/are true? a. Fishing practices have removed 90% of large marine predatory fish species. b. In U.S. waters, 80% of commercial marine fish stocks are fully exploited or overfished. c. A recent study indicates that if fishing practices continue, marine fish stocks will be depleted by 2048. d. Most marine fish stocks are currently being fished at their maximum sustainable yield. e. The marine fishing industry has developed new high-tech methods that have virtually eliminated bycatch. f. The world's total marine fish catch continues to increase year after year.
a, b, c
Of the following statements about temperature of water and its effect on marine life, which is/are true? a. Warm-water species tend to be individually smaller and reproduce earlier than cold-water species. b. Warm-water species comprise a greater number of species and reproduce more frequently than cold-water species. c. Warm-water species constitute a much smaller biomass than cold- water species. d. Warm-water species tend to be individually smaller and live for longer periods of time than cold- water species. e. Warm-water species tend to be larger and live for shorter periods of time than cold-water species.
a, b, c
Of the following nutrients, which is/are used in photosynthetic primary productivity by phytoplankton? a. iron b. nitrates c. silica d. phosphates e. calcium f. boron
a, b, c, d
Of the following statements about feeding strategies, which is/are true? a. Carnivorous feeding involves either passive or active predation. b. Carnivorous feeding involves organisms directly capturing and eating other animals. c. Deposit feeders include worms that ingest sediment that is coated with organic matter. d. Suspension feeding involves filtering plankton from seawater. e. Suspension feeding is the same thing as filter feeding.
a, b, c, d, e
Of the following statements about the characteristics of marine mammals, which is/are true? a. Marine mammals evolved from land species. b. Marine mammals have hair (or fur) during at least some stage of their development. c. Marine mammals bear live young. d. Marine mammals are warm-blooded. e. Marine mammals must surface to breathe air. f. Marine mammals need to come ashore to give birth.
a, b, c, d, e
Of the following adult-stage organisms, which is/are classified as benthos? a. Marine snails b. Crabs that crawl across the sea floor c. Sea anemones d. Mussels e. Barnacles f. Sponges
a, b, c, d, e, f
Of the following statements about bioluminescence in deep-water nekton, which is/are true? a. Deep-water nekton can use bioluminescent light to communicate with or attract a mate. b. Deep-water nekton can use a flash of bioluminescent light to temporarily blind a predator and escape. c. Deep-water nekton can use bioluminescent light to stake out territory by constantly patrolling an area. d. Deep-water nekton can use bioluminescent light to achieve neutral buoyancy. e. Deep-water nekton can use bioluminescent light to attract and lure prey. f. The majority of deep-water nekton can bioluminesce.
a, b, c, e, f
Of the following adaptations, which is/are used by various pelagic organisms to keep them from sinking? a. intricate ornamental body projections b. soft, gelatinous bodies with little if any hard tissue c. expansion and contraction of the overall body size to regulate buoyancy d. fatty organs that effectively increase buoyancy e. swim bladders that use gas to regulate buoyancy
a, b, d, e
Of the following statements about plankton, which is/are true? a. Plankton can move up and down in the water column. b. Plankton are very abundant and comprise most of Earth's biomass. c. Plankton comprise 98% of all marine species. d. Plankton also include certain types of bacteria. e. Plankton drift with ocean currents.
a, b, d, e
Of the following whales, which one(s) are baleen whales? a. humpback whales b. right whales c. sperm whales d. blue whales e. gray whales
a, b, d, e
Of the following adaptations, which tend(s) to increase an organism's ability to float? a. The development of intricately shaped body surfaces, such as unusual appendages or rings b. The development of lots of spines c. The development of more streamlined bodies d. A decrease in the ratio of surface area to volume e. An increase in the ratio of surface area to volume
a, b, e
Of the following types of organisms, which are examples of microscopic algae? a. coccolithophores b. dinoflagellates c. photosynthetic bacteria d. krill e. diatoms
a, b, e
Of the following statements about oceanic productivity in polar regions, which is/are true? a. In polar oceans, productivity is limited by the lack of sunlight in the winter. b. In polar oceans, productivity is high year-round. c. Polar oceans typically display a strong, permanent thermocline. d. In polar oceans, there is incredibly high productivity in the summertime. e. In polar oceans, nutrient concentrations are usually adequate and do NOT limit productivity.
a, d, e
Of the following statements about schooling, which is/are true? a. Schooling reduces the percentage of ocean volume in which a cruising predator might find one of their kind. b. Schooling allows fish to learn avoidance techniques from each other through observation and socialization. c. Schools can gang up on larger predators and chase them away, thus avoiding an attack. d. Schooling provides conservation of body heat and allows fish to be warmer, thus using less energy to keep warm. e. More than half of all fish species are known to join schools during at least a portion of their lives. f. Schools can move and appear as one large and dangerous fish, thus preventing a predator from attacking.
a, e, f
Of the following statements about marine mammals in suborder Odontoceti, which is/are true? a. Odontoceti have the ability to use echolocation. b. Odontoceti lack vocal cords. c. Odontoceti have large brains relative to their body size. d. Odontoceti form long-lived social groups. e. Odontoceti have prominent teeth and good vision.
a,b, c, d, e
Of the following characteristics, which is/are true of marine mammals of order Sirenia? a. Their ancestors were wolf-like creatures. b. They have a paddle-like tail and rounded front flippers. c. They are the only vegetarian marine mammals. d. They live in shallow water and move slowly, which can often endanger them to being run over by boats. e. Sirenians include manatees, which have nails on their front flippers. f. They have sparse hairs that are concentrated around the mouth but cover their bodies.
b, c, d, e, f
Of the following locations, where would you expect to find the HIGHEST annual oceanic productivity? Select only one answer. a. in low-latitude waters along a continental margin b. in low-latitude waters in the open ocean c. in middle-latitude waters along a continental margin d. in middle-latitude waters in the open ocean e. in high-latitude waters along a continental margin f. in high-latitude waters in the open ocean
c
What does sonar data tell us about the seafloor?
depth, shape, and composition
Where do dolphins generate sounds for use in echolocation?
in the blowhole
In dead zones resulting from eutrophication, animal life is absent due to the lack of _________.
oxygen
The fins used by fishes primarily for maneuvering are _________.
pectoral and pelvic
One of the prey items of baleen whales are krill. What are krill?
small shrimp-like organisms
Marine fishes usually do not survive in freshwater because of _________.
the effects of osmotic pressure
Individual fishes within schools maintain their spacing through visual contact and _________.
the lateral line system
Which side of the baleen faces inside the mouth on a living whale?
the more fibrous side
The most sophisticated use of sound by marine mammals is found in the _________.
toothed whales
A fact regarding photosynthesis is that _______ and _______ are converted to _______ and ______.
water, carbon dioxide, oxygen, sugar
Compare the macroscopic algae in terms of color, maximum depth to which they grow, and size.
• Phaeophyta (brown algae): The dominant color is brown to black. They may grow attached to ocean bottoms at depths of 30 meters (100 feet) or more. The brown algae range in size from the small genus Ralfsia that is a common encrusting form on intertidal rocks to the 30-meter (100-foot) long Pelagophycus (bull kelp). In the Sargasso Sea, a free-floating brown alga gives the area its name, Sargassum. • Chlorophyta (green algae): The dominant color is green, and green algae are found in the shallow intertidal zone only. The majority of species are less than 30 centimeters (12 inches) in maximum dimension. Ulva, sea lettuce, is common in tidal pools in colder waters while Codium, sponge weed, is widely distributed in warm water coastal areas. • Rhodophyta (red algae): The dominant color is pink to dark red. These algae can use short blue and green wavelengths of light for photosynthesis; they are the group of algae found growing attached to the ocean floor at the lower portion of the photic zone. They have been found at depths up to 268 meters (880 feet), and Corallina is common in rocky intertidal areas.
