GEOS 3333 Ch. 13 - Marine Ecosystems

standing stock

available biomass of a target species

Of the following locations, where would you expect to find the HIGHEST annual oceanic productivity? Select only one answer.

in middle-latitude waters along a continental margin

by-catch

incidental catch

Productivity in polar oceans is:

light-limited.

anchovy

herbivore

In general, the rate at which energy is stored by organisms through the formation of organic matter is called:

primary productivity

sand star (Astropecten)

carnivore

Of the following statements about marine fisheries, which is/are true?

-A recent study indicates that if fishing practices continue, marine fish stocks will be depleted by 2048. -In U.S. waters, 80% of commercial marine fish stocks are fully exploited or overfished. -Fishing practices have removed 90% of large marine predatory fish species.

Of the following statements about feeding strategies, which is/are true?

-Carnivorous feeding involves organisms directly capturing and eating other animals. -Deposit feeders include worms that ingest sediment that is coated with organic matter. -Suspension feeding is the same thing as filter feeding. -Carnivorous feeding involves either passive or active predation. -Suspension feeding involves filtering plankton from seawater.

Of the following statements about oceanic productivity in polar regions, which is/are true?

-In polar oceans, nutrient concentrations are usually adequate and do NOT limit productivity. -In polar oceans, productivity is limited by the lack of sunlight in the winter. -In polar oceans, there is incredibly high productivity in the summertime.

Of the following statements about oceanic productivity, which is/are true?

-In tropical oceans, productivity is limited year-round by the lack of nutrients. -In middle-latitude oceans, the fall bloom is limited by the lack of sunlight. -In middle-latitude oceans, the spring bloom is limited by the lack of nutrients.

Of the following nutrients, which is/are used in photosynthetic primary productivity by phytoplankton?

-Iron -Nitrates -Silica -Phosphates

Of the following locations, which is/are exceptions to the general rule that productivity is steady and low in tropical regions?

-coastal upwelling -coral reefs -equatorial upwelling

The percentage of euphotic zone biomass that reaches the deep ocean floor is approximately:

1%

The efficiency of trophic transfers in ecosystems is on average around:

10%.

The average rate of primary production in the open ocean is 125 gC/m2/yr. In the most productive ecosystems such as algal beds and coral reefs, the average production is 2000 gC/m2/yr. How many years would it take to accumulate 2000 gC/m2 on the deep-sea floor in the open ocean?

1600 years

Although primary productivity in tropical areas is generally low, which of the following tropical locations have unusually high primary productivity rates?

All the above tropical areas have relatively high primary productivity.

An overabundance of oxygen results in eutrophication.

False

Compensation depth is the depth in the ocean where the photosynthetic rate exceeds the rate of cellular respiration.

False

If the total caloric content of the autotrophic organisms in a marine ecosystem were 250,000 kilocalories (kcal), then the expected caloric value for the trophic-level consumers at the second level would be 2,500 kcal.

False

Primary productivity is equal to the amount of photosynthesis plus the amount of respiration.

False

The products of photosynthesis are carbon dioxide (CO2) and water (H2O).

False

The standing stock of a population is the maximum number or biomass of individuals that can be removed sustainably.

False

The area of the ocean that produces the largest standing stock of commercial fish is in the:

Nontropical shelf areas.

The most abundant marine macroscopic algae are members of the Division:

Rhodophyta.

The group of marine macroscopic algae with the highest abundance and greatest geographic distribution belong to the Division Rhodophyta.

True

Bacteria that manufacture carbohydrates in the absence of solar energy are autotrophs.

True

Marine algae that grow close to the limits of light penetration have accessory photosynthetic pigments that absorb high energy, short-wavelength light in the blue region of the electromagnetic spectrum.

True

The amounts of carbon dioxide and available nutrients affect the rate of primary production in an ecosystem.

True

Marine seed-bearing plants include all the following except :

Ulva

diatom

autotroph

dolphin

carnivore

The depth at which the cellular respiration rate equals the photosynthetic rate is referred to as the:

compensation depth for photosynthesis.

flounder

consumer

Nutrient flow in an ecosystem is:

cyclical.

Amphipods are _________.

deposit feeders

Important marine autotrophs that have silica incorporated into their cell walls are:

diatoms

With the depletion of fish stocks in coastal waters, more fishing is being conducted in deeper waters. Deep-water species are becoming endangered at a rapid rate, primarily because _________.

most deep-water organisms have lower metabolic rates; therefore, they grow, mature, and reproduce at a slower rate

Sargassum

producer

Mass mortality events of marine mammals and birds may occur after ingesting prey items that contain algal toxins. What organism that can cause harmful algal blooms should humans be concerned about if animals in the area are having seizures and exhibiting erratic, "drunken-like" behavior?

pseudo-nitzschia, because it causes amnesic shellfish poisoning.

The relative productivity in the world's oceans from most productive to least productive is:

temperate waters, polar waters, tropical waters.

If primary photosynthetic productivity in a given area of the ocean is 300 gC/m2/yr, about how much organic matter is added to the seafloor sediments per square meter each year?

three grams

A fact regarding photosynthesis is that _________.

water and carbon dioxide are converted to oxygen gas and sugar