Aquatic Ecology - lecture questions

Why do freshwater ecosystem have so much diversity?

Freshwater ecosystems have high biodiversity because they offer a wide range of habitats, are often isolated (leading to unique species), and support complex food webs due to nutrient-rich conditions.

"The renewable portion of freshwater resources is typically considered to be the amount of _____________."

Runoff

Precipitation

Groundwater

Evaporation

Runoff

Which of the following properties of water is NOT because of the polar nature of the water molecule??

The high latent heat of vapourization of water

Ice (solid water) having a lower density than water (liquid water)

Gases are more soluble in deeper water

The strong ability of water to dissolve other substances

Gases are more soluble in deeper water

Based on the described attributes which of the following ponds should have the fastest rate of light attenuation?

Pond A: low productivity; colourless; few inorganic particulates

Pond B: high productivity; colourless; few inorganic particulates

Pond C: high productivity; tea-stained colour; few inorganic particulates

Pond D: high productivity; tea-stained colour; lots of inorganic particulates

Pond D: high productivity; tea-stained colour; lots of inorganic particulates

Select the following description of a landscape that is most likely to generate the greatest amount of runoff.

A. Gently sloping landscape with sandy soils, moderate rainfall, and dense vegetation promoting infiltration and evapotranspiration.

B. Steep terrain with compacted clay-rich soils, low porosity, minimal vegetation cover, and frequent intense rainfall events.

C. Rolling hills underlain by permeable sandstone with moderate precipitation and a well-developed forest canopy.

D. Flat lowland area with silty soils, moderate vegetation, and rainfall levels approximately equal to evapotranspiration.

B. Steep terrain with compacted clay-rich soils, low porosity, minimal vegetation cover, and frequent intense rainfall events.

Why?

Steep slope → promotes surface runoff

Clay soils → very low hydraulic conductivity (hard for water to soak in)

Low porosity & minimal vegetation → less water absorbed or used by plants

Frequent heavy rain → lots of water input with little absorption = high runoff

Dr. Yates is doing a tour of a forest with some students when one asks if the forest is a swamp. Which of the following attributes should Dr. Yates NOT use to determine if the area is a swamp?

The presence of hydrophytic plants

The presence of standing water in small depressions

The presence of gray soils in the mineral layer

The presence of high organic content in the surface soils

The presence of standing water in small depressions

Select the following river catchment description that is most likely to have the largest annual discharge.

A. A small catchment in an arid biome with sandy soils, low annual precipitation, and high infiltration rates.

B. A large tropical rainforest catchment with high annual rainfall, clay-rich soils, and dense vegetation cover.

C. A mountainous catchment with steep slopes, intermittent rainfall, and permeable bedrock.

D. A mid-sized temperate catchment with moderate precipitation and extensive urban development.

B. A large tropical rainforest catchment with high annual rainfall, clay-rich soils, and dense vegetation cover.

Explanation:

Large catchment → Greater area contributes to flow

Tropical rainforest → High precipitation year-round

Clay-rich soils → Slower infiltration = more runoff

Dense vegetation helps store water, but in a rainforest setting, the net precipitation far exceeds evapotranspiration, supporting high discharge

Stratification is the formation of _____________ and occurs when __________.

distinct layers of water in the lake; lack of mixing results in warmer above colder water

distinct layers of water in the lake; lack of mixing results in more dense water above less dense water

thermal gradient in the water of the lake; lack of mixing results in warmer water below colder water

distinct layers of water in the lake; lack of mixing results in less dense water above more dense water

distinct layers of water in the lake; lack of mixing results in less dense water above more dense water

"An organism's trophic classification is based on ____________."

how an organism interacts with other organisms

what the organism is eaten by

where the organism eats

what the organism eats

what the organism eats

"Algae that are always photosynthetic and multi-cellular"

Bacillariophyceae

Charophytes

Cyanobacteria

Chlorophytes

Chlorophytes

Select the scenario below that is most likely to have anoxic conditions.

In the epilimnion of a lake in the summer following stratification

At the sediments of the profundal zone of a deep, dimictic, lake in the springtime

A wetland with large amounts of submerged macrophytes in the nighttime

In a shallow, turbulent stream with extensive algae coverage

A wetland with large amounts of submerged macrophytes in the nighttime

Dr. Yates is sampling a pond with a pH of 7. Which of the following descriptions best describes the relative abundances of inorganic carbon forms he will find in the pond?

Lots of carbonate, some bicarbonate and very little carbonic acid

Lots of bicarbonate, some carbonate and very little carbonic acid

Lots of carbonic acid, some carbonate and very little bicarbonate

Lots of bicarbonate, some carbonic acid and very little carbonate

Lots of bicarbonate, some carbonate and very little carbonic acid

Select the option below that best describes the levels of nitrate and ammonium in the epilimnion of a monomictic lake in the winter and summer seasons

Winter: nitrate = high, ammonium = high; Summer: nitrate = low, ammonium = high

Winter: nitrate = low, ammonium = low; Summer: nitrate = high, ammonium = high

Winter: nitrate = high, ammonium = high; Summer: nitrate = low, ammonium = low

Winter: nitrate = low, ammonium = low; Summer: nitrate = high, ammonium = high

Winter: nitrate = high, ammonium = high; Summer: nitrate = low, ammonium = high

Select the Lake ecosystem below where the photosynthesizers are most likely to be limited by phosphorus.

Lake B: N concentration = 10 ug/L, P concentration = 15 ug/L

Lake A: N concentration = 74 ug/L, P concentration = 2

Lake B: N concentration = 100 ug/L, P concentration = 30 ug/L

Lake B: N concentration = 20 ug/L, P concentration = 4 ug/L

Lake A: N concentration = 74 ug/L, P concentration = 2 ug/L

Eutrophication is a _____________ process that is caused by the build-up of _____________ in a waterbody leading to increased ________________.

Natural/Nutrients/Primary Production

Anthropogenic/Oxygen/Primary Production

Natural/Oxygen/Water Clarity

Anthropogenic/Nutrients/Primary Production

Anthropogenic/Nutrients/Primary Production

• even though Natural/Nutrients/Primary Production is also technically true, it takes too long and usually is not what is meant in this context

Which of the following strategies for consumption of micro-organisms by macro-organisms does NOT involve processing large amounts of material with little or no nutrient value?

Shredding

Filtering

Scraping

Shredding

A snail reproducing at a smaller size in the presence of predators is an example of a ________________ adaption.

Behavioural

Life History

Chemical

Mechanical

Life History

Which of the following is the best example of exploitative (or scramble) competition?

A filamentous algae grows over the top of benthic diatom species reducing the diatom's access to light

A phytoplankton bloom reduces the amount of phosphorus in the water column

Larger crayfish exclude smaller crayfish from the best food resources

One piscivorous fish species is able to catch more or a prey species that a second piscivorous species

A phytoplankton bloom reduces the amount of phosphorus in the water column

"The seasonal shift in the dominance of groups of phytoplankton is driven by _________________ and results in changes in the concentration of ____________."

temperature; oxygen

temperature; nutrients

nutrients; oxygen

oxygen; nutrients

temperature; nutrients

The continuous accumulation of mercury in the tissues of a top predator that reduces reproductive output of the organism over its life span is an example of a ________________ exposure and a ________________ response.

A) Chronic exposure and a sublethal response

B) Acute exposure and a lethal response

C) Chronic exposure and a lethal response

D) Acute exposure and a sublethal response

A) Chronic exposure and a sublethal response