GEOL1345 Midterm 3 Review
Except for Trophic Level 1, on average about _____% of the mass that is taken in at one trophic level is passed on to the next.
10
In relatively clear ocean water, about how deep is the photic zone (the zone where light penetrates from the surface in sufficient amounts for photosynthesis to occur).
100 m
What percentage of marine species are "pelagic", i.e., they live in the water column?
2%
What percentage of marine species live on or in the ocean floor (are classified as benthic)?
98%
Which of the following statements about symbiosis is FALSE?
Cannibalism is a type of symbiosis in which one party gets eaten.
It might seem a bit unusual that the richest concentration of marine life is (1) at the very margins of the oceans, where conditions are the least stable; and (2) in colder water, which seems less conducive to sustaining life. What factor(s) provide an explanation of these observations?
Cold water holds more dissolved carbon dioxide than warm water, and nutrient availability is greater in the margins of the oceans.
Of the following statements, which one best describes copepods?
Copepods are microscopic shrimp-like animals that are a vital link in many marine food webs.
How does water temperature affect growth rates and viscosity?
Decreasing temperature increases viscosity
Different osmosis strategies for freshwater and saltwater fish
FRESHWATER: hypertonic to their environment, problem with too much water entering cells; to avoid this problem: do not drink, have cells that absorb salt, produce large quantity of dilute urine MARINE: hypotonic to seawater, problem is water loss from cells; to avoid this problem: drink lots of water, secrete salt through special cell, excrete concentrated urine to conserve water
True or False: temperatures are more extreme in the ocean when comparing the marine and terrestrial environments.
False
Adaptation for extracting oxygen from seawater (gills)
Gills: fibrous organs that take in oxygen and give off CO2; more gas can be dissolved in colder water and this is why phytoplankton stocks are large in polar waters
What is the difference between gross and net productivity? How large is the net productivity?
Gross - the total amount of organism matter produced by photosynthesis per unit time Net - GPP minus respiration and is used for growth and reproduction Net Production - production due to nutrients brought in from outside the system atmospheric deposition Regenerated Production - Production from nutrients that have been recycled in the system (within the photic zone) For phytoplankton, Net Primary Production is about 90% of Gross Primary Production (10% used for respiration)
Where is biologic productivity high?
High productivity zone in polar zones because CO2 dissolved more readily and more nutrients
The oxygen minimum layer (OML) or zone is ______ .
Is a zone of low dissolved oxygen concentration.
Most invertebrates and fish of the pelagic realm use oviparous reproduction. What does that mean?
It increases the ratio of surface area to volume, which creates more drag with the water, so it does not sink quickly; it increases their ability to absorb nutrients from the surrounding water; it increases their ability to dispose of waste by diffusion
Of the following, which one is believed to be the MOST important function of schooling?
It offers protection from predators.
Although some macroalgae have a plant-like form, how are they different and why?
Kelp are the largest algae in terms of size (common in temperature and cold water areas) Green Algae are not very common in the open ocean Red Algae are abundant and widespread in the shallow waters
Role of nutrients and light determining biologic production
Light + Nutrients = Photosynthesis (Coastal waters have less light, but more nutrients) Solar radiation provides the energy for photosynthesis; most common nutrients are nitrogen and phosphorus (similar to fertilizer you use on your lawn)
Based on a working definition of life, which of the following is not a characteristic of living organisms?
Living organisms must be large enough to be seen with the naked eye.
How much of global species are marine (14%) and what is the breakdown between pelagic (2%) and benthic (98%) species numbers?
Marine: 14% Pelagic: 2% Benthic: 98%
Adaptations for maintaining depth
Most energy in the marine marine environment is at the top (sunlight); marine organisms use buoyancy and frictional resistance to maintain their desired position in the water column (ex: plankton have appendages that increase their friction with the viscous water surrounding them)
Are jellyfish benthos or nekton?
Neither: plankton
How osmosis works & effect of osmotic pressure
Osmosis is the movement of particles across a semipermeable membrane from a region of higher concentration to a region of lower concentration; the molecules want to be distributed equally; osmotic pressure increases with increasing salinity
Why do the majority of the ocean's organisms live within the ocean's surface waters?
Phytoplankton need to be in the sunlit zone, and they are the base of the entire food web.
Why are most plankton tiny, single celled organisms?
Small size gives them a large surface to volume ratio which helps to keep cells afloat (more frictional contact with water), acquire nutrients by diffusion, expel waste products by diffusion
How does photosynthesis work? Photosynthesis-respiration cycle
Solar energy is stored as chemical energy by producers; that energy is passed on to other organisms through feeding; the energy is released as heat and mechanical energy
Only 13% of Earth's species live in the ocean. Which is the most logical explanation of why there are so few marine species?
The relatively uniform conditions of the open ocean create an easier life for marine organisms than terrestrial organisms.
Unlike humans, whales can minimize the debilitating effect of deep dives because they ______.
They have collapsible lungs.
Which of the following statements about photosynthesis is true?
Water and carbon dioxide are converted to sugar and oxygen gas.
The deep waters of the ocean, where no light penetrates from the surface, are called the _______________ ?
aphotic zone
Epifauna
attached to surface hard structures or move along the sediment surface
Which of the following limits photosynthesis in tropical waters?
availability of nutrients
A nektonic organism must ______ .
be a strong swimmer
In temperate ocean waters, the spring phytoplankton bloom occurs as a spike in phytoplankton numbers during the spring. What is the main reason why the number of primary producers falls rapidly after the bloom?
because of a strong thermocline nutrients for growth become depleted in surface waters and zooplankton eat the phytoplankton
Why does the distribution of benthic biomass mimic the distribution of surface water biomass?
benthic biomass is controlled by the supply of detritus from the surface
Which of the following is NOT a common method that pelagic organisms use to maintain their vertical position in the water (i.e., float)?
big air-filled bones
As a group, deep-water nekton are known to exhibit all of the following adaptations EXCEPT ______ .
bright, colorful bodies
The figure above shows two organisms that live on sedimented shores. Both do something (a behavior) that is a common adaptation for life on sedimented shores. What is it?
burrowing
What three nutrient elements are the basis for the major biogeochemical cycling in the ocean?
carbon, nitrogen, phosphorus
Of the following fin types, which one is most commonly used to propel a fish forward?
caudal fin
Which of the following groups does the "Portuguese man-o-war" (Physalia) belong to?
cnidarians
Aphotic Zone
dark deep sea
In middle-latitude waters, nutrients ______ during the spring because ______ .
decrease; they are getting used up by phytoplankton
Dead and decaying organic matter, including waste products, is called ______ ?
detritus
Heterotrophic
does not make own food (i.e. animals)
Why are most deep-sea fish generally small and sluggish?
food is scarce in deep water, favoring a less energetic lifestyle
Chlorophyll is _____ in color; a group of organisms that contain chlorophyll is called _____ .
green, phytoplankton
Hunter-cruiser fish often have body temperatures that are higher than the surrounding water. Why?
it increases the power output of muscles
What kind of organism is an "autotroph"?
it makes its own food via photosynthesis
All of the following adult-stage organisms are considered benthos, except ______?
jellyfish
All of the following adult-stage organisms are considered nekton, except ______ ?
jellyfish
All of the following, except one, are adaptations for deep-sea fish. Which one is not?
large bodies
In marine food webs, individual members of a feeding population are generally ______ in size and _____ numerous than their prey.
larger, less
Why are sessile benthic (bottom-attached) plants only common in the near shore zone and continental shelves?
light can penetrate all the way to the seafloor on the shelves
Which of the following is not usually an environmental factor for marine life, but is more of a problem in the terrestrial environment?
limited moisture
If someone brought you an organism washed up on the beach along a rocky shore coastline and it consisted of soft body parts, what would be your conclusion about the zone in which it lives?
low tide zone
Kelp belongs to which of the following type of organism?
macroalgae
Autotrophic
makes own food (i.e. plants)
Which of the following is NOT a characteristic exhibited by marine mammals?
marine mammals have gills
When a fishery is overfished, the baby fish are not replaced in sufficient numbers to replace the harvested fish and the population declines. Oceanographers express this as the maximum fish biomass that can be removed from the ecosystem yearly before decline begins. What is the term for this level of fish catch?
maximum sustainable yield
Organisms that are plankton in their juvenile stage, but are considered nekton or benthos in their adult stage are called ______ .
meroplankton
In middle-latitude waters during the winter, the supply of sunlight is _______ and the supply of nutrients is ________ .
minimized, maximized
Which of the following kingdom of organisms lack a cell nucleus?
monera
Of the following ocean locations, where would nutrient concentrations be highest?
near continents
The figure below shows some odd-looking fish. They have features such as big mouths, hinged jaws, bioluminescent lures, and upward-looking eyes. Where would you find such fish?
near the bottom of the deep ocean
Which of the following pairs correctly links a descriptor with the way that the organism lives in the ocean?
nekton - swimmer
Which ecosystem produces the largest percentage of the world's marine fishery?
non-tropical continental shelves
Of the following groups, which one is highly skilled in the ability to use echolocation for navigation and communication?
odontoceti
Chemosynthetic organisms occur in the Gulf of Mexico at what locations?
oil seeps
Benthos/Benthic
organisms that live on or within the ocean bottom
What are chemosynthetic organisms?
organisms that produce their own energy and organic matter through chemical reactions
What is the difference between phytoplankton and zooplankton?
phytoplankton photosynthesize and zooplankton do not
Dinoflagellates are a type of _______ that is associated with ________ .
phytoplankton, harmful algal blooms
Which type of marine organism comprises the greatest marine biomass?
plankton
Meroplankton are organisms that are planktonic for part of their lives. Many meroplankton are larvae or juveniles of animals that become benthic as they grow up. Why is this a good life strategy?
planktonic larvae and juveniles can spread to different locations, increasing the odds of species survival
Corals are colonial animals that secrete a carbonate skeleton. Individual corals are called what?
polyp
Euphotic Zone/Photic Zone
puppet ocean where most light generates and photosynthesis is abundant - generally 0-100 m
Photosynthesis takes carbon dioxide, water, and uses sunlight to fix energy as carbohydrates and give off oxygen. What is the name of the opposite process, which takes oxygen and carbohydrates, releases energy, and emits carbon dioxide.
respiration
Why is primary productivity high in waters over the continental shelves?
river waters carry nutrients to the sea at the continental margin
Why is species diversity (i.e., the number of different species) high on rocky coasts as compared with sedimented coasts?
rocky coasts have more varied substrate and hence more ecological niches for organisms to develop special adaptations
Which of the following organisms is not considered to a cetacean (member of the order Cetacea)?
seals and sea lions (pinnepeds)
Which of the following whales do not have baleen?
sperm whales
Organisms that can tolerate only a narrow range of salinity are called ______ .
stenohaline
What is the ultimate source of energy for food chains and webs?
sunlight (photosynthesis)
In the figure below, the cockle (left) has a siphon that reaches up into the water, which allows it to breathe and to feed. What type of feeding strategy is this?
suspension feeding
Comparing the marine and terrestrial environment, which of the following is NOT true?
temperatures are more extreme in the ocean
Why are most coral reefs found in shallow water?
the coral polyps need plentiful light so their zooxanthellae can perform photosynthesis
In the coral disease known as "coral bleaching", what causes the bleaching?
the corals expel the zooxanthellae that normally give them color
A fishery's maximum sustainable yield (MSY) is defined as ______ ?
the maximum fishery biomass that can be removed yearly and still be sustained by the fishery ecosystem
Epipelagic Zone
the part of the ocean where there is enough sunlight for algae to utilize photosynthesis
Biomass
the total quantity or mass of organisms of a specific class or in a specific volume
Why are there fewer numbers of organisms at higher trophic levels?
there is more energy to create biomass at lower trophic levels
Microscopic algae are important in the marine environment. Which one of the following statements about them is NOT true?
they filter seawater and remove pollutants
Marine mammals have all of the following characteristics, except for one. Which one is NOT a characteristic of marine mammals?
they have a keen sense of smell
Most invertebrates and fish of the pelagic realm use oviparous reproduction. What does that mean?
they lay lots of eggs and do not care for them
Which of the following is an evolutionary adaptation made by most marine mammals to live in the marine environment?
thick insulation to conserve internal heat
Why are most fish and marine mammals streamlined in shape?
this shape minimizes drag as they move through the water
Why do sharks have asymmetric, heterocercal tail fins?
this type of fin gives them lift to keep them from sinking
Whales fall into two categories: __________________________________.
those with teeth and those with baleen
Why do many tropical zooplankton, like copepods, have appendages with ornate plumage while their polar cousins are not so ornate?
to create friction and keep from sinking because tropical water is less viscous
What is bycatch?
unwanted marine organisms caught incidentally during fishing
Which of the following regions typically shows high biologic productivity?
upwelling zones near continents
Which of the following conditions is a requirement of coral reefs?
water warmer than 18°C
Role of upwelling in biologic productivity
Brings nutrient rich water to the surface and causes phytoplankton blooms
Marine environment vs. terrestrial environment - how different?
TERRESTRIAL: Main limiting factor is the availability of water (rainforest vs desert), wide temperature swings, O2 decreases with altitude, terrestrial organisms have special adaptations for living in air, plenty of light MARINE: Water plentiful (obviously), most organisms are more than half water anyways, so marine organisms are not in danger of desiccation (drying out ) like terrestrial organisms, water is more viscous than they are (harder to move through it), large pressure and light gradients from top to bottom
Productivity patterns - know the patterns and why they occur a. polar b. tropical c. temperate
a. Polar: limiting factor is sunlight for primary producers; winter productivity is low because of low light; spring sunlight, primary producers increase several fold (spring bloom); primary producers are eaten and decrease in abundance in late summer followed by zooplankton b. Tropical: sun heats surface waters which forms a stable thermocline; very little vertical mixing; low nutrient concentrations in the photic zone because nutrients are used up by plankton and not replaced; causes low primary production used up by plankton and not replaced; causes low primary production by phytoplankton c. Temperate: bloom in grazers results from algae food supply; time lag reflects reproduction time; declining nutrients and predation cause algae bloom to crash; full algae bloom results from increased nutrients resulting from storms and mixing
Plankton
an organism is considered plankton if it is carried by tides and currents, and cannot swim well enough to move against these forces
Dinoflagellates sometimes reproduce in such large numbers that they color surface waters red and these are called "red tides" (although they have nothing to do with tides). Not all blooms of toxic dinoflagellates discolor the water, so oceanographers prefer the term ____________ .
harmful algal blooms (HAB)
Disphotic Zone
in this zone only a small amount of light penetrates the water; plants do not grow here due to the insufficient amount of light
In middle-latitude waters, productivity of marine algae______ during the spring because ______.
increases, the amount of sunlight is increasing
Benthic organisms are sometimes classified as either infauna or epifauna. What is the difference?
infauna live within the sediments whereas epifauna live on the surface of the sea bottom