Final Exam Review

Question 1

Water is the only natural substance found in … on planet earth

Answer 1

Solid
Liquid
Gas

Question 2

Why is water’s specific heat property beneficial for a cold-water fish

Answer 2

Allows the water to maintain a relatively stable temperature. Stability of the water supports the fish’s thermal preferences and metabolic processes, and acts as a buffer against rapid environmental temperature fluctuations that could otherwise stress the fish

Question 3

When is water least dense

Answer 3

0°C (32°F), its freezing point

Question 4

When is water most dense

Answer 4

around 3.98°C (39°F)

Question 5

Describe the relationship between water temperature and density?

Answer 5

As water temperature increases, its density decreases

Water has an anomaly - its density increases from 0°C to 4°C, then decreases.

The maximum density of water occurs at around 4°C

Question 6

What is viscosity? How does the viscosity of water affect aquatic life?

Answer 6

Viscosity is a measure of a fluid’s resistance to flow or “thickness.”

Liquids with high viscosity, like honey, flow slowly and are “thick.”

Liquids with low viscosity, like water, flow easily and are “thin.”

Viscosity is affected by temperature - as temperature increases, viscosity decreases.

Viscosity is important for aquatic life, as it affects swimming efficiency, feeding, and other behaviors.

Question 7

What is the light compensation level? How does this affect aquatic life at different water depths?

Answer 7

Light compensation level is the depth in the ocean where light levels are very low, and only a few species of phytoplankton can survive. This depth varies depending on water clarity and the efficiency of different phytoplankton species in low light conditions

Question 8

What are 3 factors that impact the concentration of dissolved gases in water?

Answer 8

Temperature: Warmer water holds less dissolved oxygen than colder water.

Turbulence and water movement: More turbulence and movement, like from wind or waterfalls, helps dissolve more oxygen from the air into the water.

pH and chemical reactions: Changes in the water’s pH and chemical reactions can affect how much oxygen can dissolve.

Question 9

What is the most important gas that impacts aquatic life

Answer 9

Oxygen

Question 10

Is there more Dissolved Oxygen in saltwater or freshwater? Why?

Answer 10

Freshwater generally has more dissolved oxygen than saltwater because freshwater is colder and gets more oxygen from the air and plants. Saltwater is warmer and gets less oxygen from the air, so it tends to have lower levels of dissolved oxygen

Question 11

What are 2 ways that DO is added to waterbodies?

Answer 11

Aeration through rabbis or crashing into rocks

Aquatic vegetation from plant life

Question 12

Understand the water quality parameters (definitions& common units) we discussed in class:

Answer 12

a. Dissolved oxygen:

Definition: The amount of oxygen dissolved in water, which is crucial for the survival of aquatic organisms.

Common unit: milligrams per liter (mg/L) or parts per million (ppm).

b. Dissolved CO2:

Definition: The amount of carbon dioxide gas dissolved in water, which affects pH levels and can influence aquatic life.

Common unit: milligrams per liter (mg/L) or parts per million (ppm).

c. pH:

Definition: A measure of the acidity or alkalinity of water, indicating the concentration of hydrogen ions.

Common unit: pH scale (0-14), where 7 is neutral, below 7 is acidic, and above 7 is alkaline.

d. Total Dissolved Solids (TDS):

Definition: The combined content of all inorganic and organic substances dissolved in water, often including salts, minerals, and organic matter.

Common unit: milligrams per liter (mg/L) or parts per million (ppm).

e. Turbidity:

Definition: The cloudiness or haziness of a fluid caused by suspended particles, which can affect the penetration of light and aquatic ecosystems.

Common unit: Nephelometric Turbidity Units (NTU) or Formazin Nephelometric Units (FNU).

f. Alkalinity:

Definition: The capacity of water to resist changes in pH when an acid or base is added, often related to the presence of bicarbonate, carbonate, and hydroxide ions.

Common unit: milligrams per liter (mg/L) as calcium carbonate (CaCO3).

g. Conductivity:

Definition: A measure of water’s ability to conduct an electrical current, which is influenced by dissolved ions and can indicate the presence of contaminants.

Common unit: microsiemens per centimeter (μS/cm) or millisiemens per meter (mS/m).

h. Salinity:

Definition: The concentration of dissolved salts in water, typically sodium chloride (table salt), which affects water density and buoyancy.

Common unit: parts per thousand (ppt) or practical salinity units (PSU).

i. Temperature:

Definition: The degree of hotness or coldness of water, which affects various physical and biological processes in aquatic ecosystems.

Common unit: degrees Celsius (°C) or degrees Fahrenheit (°F).

Understanding these parameters and their units can help in assessing and monitoring the quality of water bodies and their suitability for various uses.

Question 13

What are the critical levels of DO, pH for freshwater fish?

Answer 13

Dissolved Oxygen (DO): Minimum: Freshwater fish need at least 5 milligrams of oxygen per liter of water to breathe comfortably. If it drops below 2, they start to struggle, and below 1 can be deadly. Optimum: Fish are happiest when there’s 6 to 8 milligrams of oxygen per liter of water.

pH: Minimum: The water should be a bit above 6.5 on the pH scale to keep fish from getting stressed. Anything below 6 can be harmful. Optimum: Fish prefer water with a pH between 6.5 and 8.5. Most do well within this range.

Question 14

Why might it be important to measure DO, pH and CO2 during the day and night?

Answer 14

Dissolved Oxygen (DO): Daytime: During the day, aquatic plants undergo photosynthesis, producing oxygen as a byproduct. This process typically increases dissolved oxygen levels in water. Nighttime: At night, photosynthesis stops, and aquatic plants consume oxygen through respiration. Additionally, oxygen consumption by aquatic organisms continues. As a result, dissolved oxygen levels can decrease during the night.

pH: Daytime: Photosynthesis by aquatic plants can affect pH levels by removing carbon dioxide from the water, which reduces acidity and raises ph. Nighttime: Without photosynthesis, carbon dioxide levels can increase due to respiration by aquatic organisms, leading to a decrease in pH as carbon dioxide dissolves in water and forms carbonic acid.

Carbon Dioxide (CO2): Daytime: As mentioned, during photosynthesis, aquatic plants absorb carbon dioxide from the water, which can lower CO2 levels. Nighttime: With no photosynthesis occurring, carbon dioxide levels may rise due to respiration by aquatic organisms and microbial activity.

Question 15

How can the concentration of CO2 in the atmosphere impact acidity of lakes and rivers?

Answer 15

Higher CO2 levels lead to more carbonic acid in water, which increases the acidity and lowers the pH. This can have significant impacts on aquatic ecosystems.

Question 15

What are the 4 nutrients that are often limited in aquatic ecosystems (in limited supply)?

Answer 15

Nitrogen (N): Helps plants and algae grow.

Phosphorus (P): Also helps plants and algae grow.

Iron (Fe): Needed by aquatic life for various processes.

Silica (Si): Important for the growth of certain types of algae.

Question 15

A sudden spike in conductivity may indicate pollution or run off event

Answer 15

True

Question 16

Explain the difference between accuracy and precision using an example

Answer 16

Accuracy: How close a measurement is to the true value.

Example: Hitting the center of a target on a shooting range.

Precision: How consistent measurements are with each other.

Example: Hitting the same spot on a target, even if it’s not the center.

Question 17

Define the 2 types of error we might encounter in aquatic studies

Answer 17

Human Error

Mechanical Error

Question 18

What is a watershed? Why is watershed-level management important

Answer 18

Watershed: a system of streams and rivers that
drain into a common outlet, main river or stream,
which flow and empty into a lake, or wetland.
Sometimes called a “drainage basin

*Lakes and streams are a reflection of the
watershed (catchment basin) they drain.
* As water passes over the surface of a
watershed it becomes “flavoured” by the
surrounding soils and vegetation.
* No other factor is as important in determining
the “trophic status” of receiving waters.
Watershed is very influential on the water
chemistry, water quality, habitat, and resultant
biological communities.

Question 19

What are the 3 major and 14 minor watersheds in Saskatchewan? (be able identify on a map)

Question 20

Differential between lentic and lotic environments

Answer 20

Lentic (Still Water): Lakes, ponds, wetlands Slow water movement, longer water residence time Thermal stratification, diverse habitats More suspended solids from internal and external sources Organisms don’t need adaptations for flowing water

Lotic (Flowing Water): Rivers, streams Fast water movement, shorter water residence time No thermal stratification, more linear habitats High suspended solids from erosion and transport Organisms need adaptations to resist the current

Question 21

Be able to classify stream order if given a diagram of a drainage system.

Question 22

What are the 3 stream categories of permanency and differences between them.

Question 23

What is the difference between littoral and limnetic zones? Provide examples of the types of fish we might expect to see in each.

Answer 23

The littoral zone, also known as the shore zone or the zone of rooted plants, is the area of a water body that is in contact with the land. This zone is characterized by the presence of rooted plants, such as grasses, reeds, and other aquatic vegetation. The limnetic zone, on the other hand, is the open and well-lit area of a freestanding body of freshwater, such as a lake or pond. It is the zone that receives sufficient sunlight, allowing for photosynthesis. The floor under the limnetic zone cannot sustain.

Question 24

Compare the 3 categories of lake productivity. What drives this productivity status?

Question 25

What is thermal stratification and why does it occur in lakes? Know the names and characteristics of each layer stratification layer. be able to label a diagram like this

Answer 25

A diagram of a structure

Description automatically generatedEpilimnion (Top Level) is the top-most layer in a
thermally stratified lake. Least dense
layer. Warmest in summer, coldest in
winter.3.9 degrees

Metalimnion (Middle level) Region where
temperature, and density change rapidly
resulting in lake stratification. The point
at which is occurs is the Thermocline

Hypolimnion(Bottom level) Dense, bottom layer of
water in a thermally-stratified lake.
Coldest in summer, warmest in winter

Question 26

How might we expect the thermal stratification layers of a deep northern Saskatchewan Lake to vary between summer and winter? Why do these changes happen?

Answer 26

During winter, the lake experiences a different thermal regime due to the cooling of the water and the formation of ice. The lake is generally in an inversely stratified state, In summer, the lake warms up due to solar radiation and wind-induced heat exchange, leading to the development of thermal stratification. In winter, the lake cools down due to the absence of solar radiation and the formation of ice, which leads to the inversion of the thermal structure.

Question 27

Know the classifications of lakes based on their stratification regime (how often they mix) (4 types)

Question 28

Know the classifications of lakes based on their stratification regime (how often they mix) (4 types)

Answer 28

A thermocline is a distinct layer in a body of water were temperature changes rapidly with depth, separating the warmer surface water from the colder, deeper water.

The thermocline has a significant impact on aquatic life: In lakes, the thermocline leads to thermal stratification, with the warmer epilimnion on top and the colder, denser hypolimnion below. This can result in less oxygen below the thermocline, as the water below never circulates to the surface.  the thermocline is an important feature that influences the habitat, distribution, and survival of aquatic organisms in both marine and freshwater environments.

Question 29

In your own words, explain how riffles and pools are formed in a river system.

Answer 29

Riffles are formed by the accumulation of boulders, which create a shallow, turbulent section of the river. The steeper slope and faster water flow over riffles help remove fine sediments, oxygenating the water. Riffles act as control points, maintaining the overall slope and elevation of the stream bed. Pools are the deeper, smoother sections of the river, often found on the outside bends of meanders or behind large obstructions like boulders. Pools form due to the fast current eroding the sides of the outside bends.

Question 30

Define erosional vs. depositional habitats.

Answer 30

Erosional Habitats:

Characterized by fast-flowing water and coarse substrate (e.g. riffles, rocky areas)

Sediments and materials are picked up and carried away by the water flow

Provide habitat for macroinvertebrates and fish species adapted to high-energy, fast-moving conditions

Examples include riffles, rocky areas, and the outside bends of meanders in rivers and streams

Depositional Habitats:

Characterized by slower water flow and finer sediments (e.g. pools, slack water areas)

Sediments and materials are dropped and accumulate in these areas

Provide habitat for macroinvertebrates and fish species adapted to low-energy, calm conditions

Examples include pools, backwaters, and the inside bends of meanders in rivers and streams

Question 31

Define velocity vs. discharge including units.

Answer 31

Velocity (V) is the speed of the water flow, typically measured in units of length per time while discharge (Q) is the volumetric flow rate of the water, typically measured in units of volume per time

Question 32

What 4 features do algae have in common?

Question 33

Know the 3 phyla of algae discussed in class, and general characteristics of each. (Do not need to know algal species)

Question 34

Name 3 features that are used to identify algae:

Question 35

What is meant by the term “zooplankton”?

Question 37

How do “rotifers” feed?

Question 38

What are the following features?

Question 40

Compare and contrast the 4 functional feeding groups for benthic invertebrates discussed in class:

Question 41

What is the EPT index? How is it used?

Answer 41

Measures the percentage of Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) in a macroinvertebrate sample.

These EPT taxa are generally more sensitive to pollution and environmental disturbances than other macroinvertebrates.

A high percentage of EPT taxa indicates good water quality and a healthy stream ecosystem.

To calculate the EPT index, the number of distinct EPT taxa is divided by the total number of macroinvertebrates, then multiplied by 100 to get a percentage.

The higher the EPT percentage, the better the water quality. EPT index values are compared to rating charts to determine overall stream health.

The EPT index is a widely used biomonitoring tool because macroinvertebrates are easy to sample and identify, and they integrate water quality over time.

Question 42

Describe 4 body shapes of fish, and what these fish are designed for

Answer 42

Fusiform (Rounded, Torpedo-Shaped):

Streamlined shape ideal for fast, continuous swimming

Often found in open water environments

Minimizes drag for efficient movement

Laterally Compressed (Flattened Sides)
Body flattened on the sides

Allows for quick turning and maneuverability

Not as strong at continuous swimming

Helps them fit into tight spaces

Laterally Depressed (Flattened Top-to-Bottom):

Body flattened from top to bottom

Helps them live on the bottom and withstand currents

Advantageous for bottom-dwelling fish

Elongate (Eel-Like):

Long, slender body shape

Allows them to fit into small crevices and burrows

Often ambush predators, not strong continuous swimmers