Aquatic Ecology

Question 1

1. Water is the only natural substance found in____________on planet earth.

Answer 1

All three states (solid, liquid, gas)

Question 2

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

Answer 2

It helps stabilize the temperature of their aquatic environment, preventing rapid fluctuations and maintaining a more consistent and suitable temperature for their survival and metabolic functions.

Question 3

3. When is water least, and most dense?

Answer 3

Least dense at 0ºC , and most dense at 3.9º C

Question 4

4. Describe the relationship between water temperature and density?

Answer 4

As water temperature increases, its density decreases

Question 5

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

Answer 5

Viscosity is a measure of fluid’s resistance to flow. Water viscosity affects aquatic life by influencing swimming efficiency, feeding ability, gas exchange, and reproductive process. (Ex: make swimming more difficult, affect feeding, reduce gas exchange, and disrupt critical life stages like reproduction and larval development in aquatic organisms.)

Question 6

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

Answer 6

Light compensation level = depth where 95% - 99% of light is extinguished.
Photic zone = depths above the light compensation level.
Most photosynthesis occurs in the euphotic zone.
Dictates where plants will grow, and algal blooms will occur

Question 7

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

Answer 7

Temperature, salinity, and pressure

Question 8

8. _____ is the most important gas that impacts aquatic life.

Answer 8

Oxygen

Question 9

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

Answer 9

There is more oxygen in freshwater then saltwater primarily due to temperature and salinity. (Freshwater tends to have cooler water then saltwater and Coldwater can hold more dissolved oxygen. Saltwater has a higher salinity due to dissolved salts. The higher the salinity of seawater affects its ability to hold dissolved oxygen).

Question 10

10. What are 2 ways that DO is added to waterbodies?

Answer 10

1. Plants in the water during photosynthesis
2. When water and air interact

Question 11

11. a) Dissolved Oxygen

Answer 11

Dissolved oxygen refers to the amount of oxygen dissolved in water, which is essential for aquatic life (Common units: milligrams per liter mg/L or parts per million ppm)

Question 12

11. b) CO2

Answer 12

Dissolved carbon dioxide is the amount of carbon dioxide gas dissolved in water, influencing water acidity and aquatic life. (common units: milligrams per liter mg/L or parts per million ppm)

Question 13

11. c) pH

Answer 13

pH is a measure of the acidity or alkalinity of water, indicating the concentration of hydrogen ions (common units: pH scale 0-14, where pH 7 is neutral, values below 7 are acidic and values above 7 are alkaline basic).

Question 14

11. d) TDS

Answer 14

Total dissolved solids represent the total concentration of dissolved inorganic and organic substances in water (common units: milligrams per liter mg/L or parts per million ppm)

Question 15

11. e) Turbidity

Answer 15

Turbidity is a measure of water clarity, indicating the presence of suspended particles and sediment (common units: Nephelometric Turbidity Units NTU or Formazin Turbidity Units FTU).

Question 16

11. f) Alkalinity

Answer 16

Alkalinity is the capacity of water to neutralize acids, primarily due to the presence of bicarbonate, carbonate, and hydroxide ions (common units: milligrams per liter mg/L as CaCO3 equivalents).

Question 17

11. g) Conductivity

Answer 17

Conductivity measures the ability of water to conduct an electrical current, influenced by dissolved salts and ions (common units:microsiemens per cm weird uS/cm)

Question 18

11. h) Salinity

Answer 18

Salinity is the concentration of dissolved salts in water, mainly sodium chloride (salt) (common units: parts per thousand ppt or practical salinity units PSU).

Question 19

11. i) Temperature

Answer 19

Temperature is the measure of the warmth or coldness of water (common units: degrees Celsius and degrees Fahrenheit)

Question 20

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

Answer 20

DO: 14.6 ppm*max under ideal conditions
pH: 6-8

Question 21

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

Answer 21

Levels of these 3 change depending on day/night.
During the day plants produce oxygen and use up CO2, which raises pH. At night they respire which does the opposite lowering oxygen, pH and increase CO2.

Question 22

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

Answer 22

Impacts the acidity through a process called acid deposition (acid rain)

Question 23

15. What are 4 nutrients that are often limiting in aquatic ecosystems (in limited supply) ?

Answer 23

Phosphorus, Nitrogen, Sulfur and Calcium

Question 24

16. T/F A sudden spike in conductivity may indicate pollution or run off event.

Answer 24

True. A sudden spike in conductivity can indicate pollution or a runoff event. Conductivity measures the ability of water to conduct.

Question 25

17. What is the difference between QA and QC? Be able to provide examples of each.

Answer 25

QA procedures refer to techniques that improve the quality of collected data (Study design, equipment used, labelling systems, record keeping, sample size) QC refers to the process of verifying that QA procedures are working properly. ( audits, equipment servicing, replicate testing, blank testing, employee knowledge testing and training).

Question 26

18. Explain the difference between accuracy and precision using an example.

Answer 26

Accuracy- How close a measurement is to its true target Precision- Consistency in results

Question 27

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

Answer 27

1.Instrument error: Inaccuracies associated with the instruments or tool; this can be caused by improper calibration. 2.Unexpected changes to the environment: Natural fluctuations of the environment can cause error in the results, taking multiple samples will help lessen the chances of this error.

Question 28

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

Answer 28

A water shed is a big area where all the rain, snow and water flow into the same place, like a river or lake. Watershed-level management is important because it helps us take care of our water resources. By managing the land and activities within a watershed, we can keep the water clean and prevent flooding.

Question 29

22. Differential between lentic and lotic environments

Answer 29

1. Lentic environments are still waters like ponds, lakes, and wetlands where water doesn’t move much. 2. Lotic environments are flowing waters like rivers, streams and creeks. Water is always on the move.

Question 30

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

Answer 30

1. Ephemeral streams- show up after it rains, flow after precipitation and not during dry periods. 2. Intermittent(seasonal)- They flow for part of the year when there’s enough water from rain or snowmelt. The rest of the time they may be dry. 3. Perennial streams- Flow all year round, usually fed by groundwater or other sources that keep them going when its dry.

Question 31

25. What is the difference between littoral and limnetic zones?

Answer 31

1. Littoral zone- part of a lake or pond that’s close to the shore. Shallow and gets a lot of sunlight, typically plants grow there. 2. Limnetic zone- open water area where it’s to deep for sunlight to reach the bottom.

Question 32

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

Answer 32

Oligotrophic lakes- these are like minimalist lakes, deep and clear with not a lot of nutrients or algae. Not a lot of plant or animal life. Mesotrophic lakes- they’ve got more nutrients than oligotrophic lakes, so they have more plants and animals. Eutrophic lakes- lots of nutrients, lots of plants and algae, often murky. Support a lot of fish but sometimes has too many algae.

Question 33

27. What is thermal stratification and why does it occur in lakes? Know the names and characteristics of each layer stratification layer.

Answer 33

1. Epilimnion- top layer that gets all sunlight. Warmest and usually has the most oxygen because its mixing with the air. 2. Metalimnion- the middle layer where the temperature drops quickly. 3. Hypolimnion- the bottom layer that’s the coldest and doesn’t get much light. Its denser and often less oxygen.

Question 34

29. What is a thermocline? Does it have any impact on aquatic life?

Answer 34

Thermocline is a distinct layer in a large body of water, where there is a rapid change in temperature with depth. This change in temperature creates a barrier between the upper layer (warmer) and lower layer (colder). Can affect aquatic life through distribution of species, many fish, zooplankton, and others prefer or thrive better in specific temperature ranges. Thermocline acts as a barrier that limits their vertical movement within their water column. Thermocline also impacts oxygen and nutrient levels. Deeper water below the thermocline may have lower oxygen levels and reduced nutrient availability influencing organisms that can thrive in different depths.

Question 35

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

Answer 35

1. Polymictic lakes- characterized by frequent and thorough mixing of their water layers. Typically shallow and may have a small surface area relative to depth. Mixing occurs regularly throughout the year. 2. Dimictic lakes- undergo two distinct periods of mixing each year. Mix completely in spring and fall (periods of temp change). 3. Monomictic lakes- experience one mixing per year. Typically occurs in winter or spring when the entire water column reaches a uniform temp. These lakes are common in colder climates. 4. Oligomictic lakes- Rarely mix completely and may have distinct layers of water that do not mix on a regular basis. Mixing may occur only under specific conditions such as severe storms.

Question 36

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

Answer 36

Riffles and Pools are created by erosions and deposition of materials and create complex habitats

Question 37

32. Define erosional vs. depositional habitats.

Answer 37

1. Erosional habitats (ex- corner pools, lateral scour pools , are habitats that have had eroding and movement of debre and material particles, clearing a space for certain species to live. 2. Depositional habitats are habitats built from materials from an erosional habitat, it is a buildup of materials that create habitats for certain species.

Question 38

36. Name 3 features that are used to identify algae:

Answer 38

Colors, colonial or single, types of chemicals in water, the amount of chlorophyll

Question 39

38. What are the 3 major groups of zooplankton discussed in class? Be able to match a picture to each group.

Answer 39

1. Rotifers 2. Copepods 3. Cladocerans

Question 40

45. What is countershading? What advantages does it provide?

Answer 40

Countershading is a color pattern where the back or top of an animal is darker-colored, and the belly or underside of the animal is light-colored or white.

Question 41

47. Know how to identify the 4 type of scales discussed in class if given a picture

Answer 41

Placoid, Ganoid, Cycloid,Ctenoid

Question 42

48. Know the mouth orientations discussed in class, and be able to identify if given a picture

Answer 42

Terminal, Superior, Inferior Sub-Terminal

Question 43

49. Know the tail shapes discussed in class, and be able to identify if given a picture

Answer 43

Heterocercal, Forked, Lunate, Emarginate, Truncate, Rounded, Pointed