final exam review

Question 1

Water is the only natural substance found in __________________ on planet earth.

Answer 1

all three states of matter at temperatures normally found on

Question 2

Viscosity

Answer 2

Resistance of fluid to a change in shape or flow

Question 3

Density

Answer 3

mass per unit volume of a substance.

Unlike most compounds, water is less dense (lighter) as a solid than as a liquid.
ice floats= least dense as a solid

Question 4

What is the Epilimnion?

Answer 4

is the top-most layer in a thermally stratified lake.
-Warmer
- typically has a higher pH and;
- higher dissolved oxygen concentration than the hypolimnion.

Question 5

What is the Thermocline?

Answer 5

Region where temperature, and density change rapidly resulting in lake stratification.
-The point at which is occurs is the Thermocline

Question 6

What is the Hypolimnion

Answer 6

dense, bottom layer of water in a thermally-stratified lake.
(layer that lies below the thermocline).
-Typically coldest layer of a lake in summer.
-warmest layer during winter.
,

Question 7

What is a limiting factor for aquatic life?

Answer 7

Light Absorbance
-You need light for plants and certain algae to conduct photosynthesis, which fuels the productivity of the entire foodweb, and impacts the water quality.

Question 8

What are the common gases found in the atmosphere?

Answer 8

Nitrogen (N2)
Oxygen (O2)
Carbon Dioxide (CO2)

Question 9

What is the Influence of temperature in regards to dissolved gases?

Answer 9

As temperature increases, the solubility of oxygen decreases.

Question 10

What is the Influence of salinity in regards to dissolved gases?

Answer 10

As salinity increases, solubility of oxygen decreases.

Question 11

How is oxygen added to a waterbody?

Answer 11

1.) Absorption across the air-water interface (turbulence helps)

2.) Flowing systems often receive O2 from groundwater

3.)Photosynthesis (respiration)

Question 12

The amount of dissolved oxygen that can be held by water depends on?

Answer 12

water temperature
salinity
pressure

Question 13

Natural limiting nutrients include?

Answer 13

Phosphorus, Nitrogen, Sulfur and Calcium.

Question 14

What is Eutrophication?

Answer 14

Enrichment of a lake or ecosystem with chemical nutrients, typically nitrogen, phosphorus.
-occurring as they age through geological time (e.g., cultural).
- Cultural eutrophication refers to nutrient enrichment by human activities

Question 15

What is Salinity?

Answer 15

Concentration of salts in water

Question 16

True or False : Suspended solids can impact turbidity and temperature?

Answer 16

True!

Question 17

Lentic: derived from the Latin word “Lentus” which means “slow or motionless”
Lentic systems include:

Answer 17

Lentic Systems=
ponds, lakes, swamps, marshes etc

Question 18

Lotic: derived from the Latin word “Lotus” which means “washing”

Lotic Systems Include:

Answer 18

Lotic systems =
streams and rivers

Question 19

When is water the most dense?

Answer 19

Most dense at 3.9º C
- This is when water molecules are closest together, resulting in the highest mass per unit volume.

Question 20

When is water the least dense?

Answer 20

Least dense at 0°C
- At this temperature, water becomes ice and expands, causing the molecules to spread out and thus decreasing its density.
-This is why ice floats on water.

Question 21

Describe the relationship between water temperature and density?

Answer 21

The relationship between temperature and density are what causes seasonal changes in lake stratification.

Question 22

What is Viscosity?

Answer 22

Viscosity is the:
resistance of fluid to a change in shape or flow.

Question 23

How does the viscosity of water affect aquatic life?

Answer 23

• Allows some organisms to be buoyant
• Dictates movement of planktonic organisms & and particles.
  -All because water is so dense.

Question 24

What is the light compensation level?

Answer 24

Light compensation level =
- depth where 95% - 99% of light is extinguished.

Question 25

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

Answer 25

-Dictates where plants will grow and algal blooms will occur. - the ability of a water to absorb and transmit light is going to dictate where life can exist, and what life can exist

Question 26

Most photosynthesis occurs in which zone in regard to water depth?

Answer 26

Euphotoic zone

Question 27

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

Answer 27

1.) Temperature 2.) Pressure 3.) Salinity

Question 28

Describe the relationship between water temperature and density? but simplify it

Answer 28

- Water is most dense at **3.9°C** - As you heat it up or cool it down from this point, it becomes less dense. -That's why ice (water at 0°C) floats on top of liquid water. - Hot water tends to rise above cooler water. -This unique property of water is crucial for supporting aquatic life.

Question 29

__________ is the most important gas that impacts aquatic life

Answer 29

Oxygen

Question 30

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

Answer 30

Freshwater holds more oxygen than saltwater. - as the salinity of water increases, the capacity of the water to hold dissolved oxygen decreases.

Question 31

What are 2 ways that DO is added to waterbodies?

Answer 31

1.) Photosynthesis 2.) Diffusion from the Atmosphere

Question 32

Dissolved Oxygen definition and common units used?

Answer 32

- milligrams per liter (mg/L) or parts per million (ppm). - Dissolved Oxygen, often abbreviated as DO, is simply the amount of oxygen that is mixed in water.

Question 33

Dissolved Carbon dioxide definition and common units used?

Answer 33

- milligrams per liter (mg/L) or parts per million by mass (ppmm). -Dissolved Carbon Dioxide, often abbreviated as CO2, is the amount of carbon dioxide gas that is mixed in water. - Sometimes, we also use microatmospheres (μatm), especially in the context of climate change and ocean acidification studies.

Question 34

pH definition and common units used?

Answer 34

- pH of a solution is the logarithm of 1 / H+ ion concentrations. - pH = -log [H+] -pH is a way to measure how acidic or basic a liquid is. It’s like a scale from 0 to 14.

Question 35

Total Dissolved Solids definition and common units used?

Answer 35

- Total Dissolved Solids, often abbreviated as TDS, is the total amount of all dissolved solids in water. - includes organic and inorganic matter -When we measure TDS, we often use units like milligrams per liter (mg/L) or parts per million (ppm).

Question 36

Turbidity definition and common units used?

Answer 36

- Turbidity is a measure of the cloudiness or haziness of a fluid, usually water. -Nephelometric Turbidity Units (NTU)

Question 37

Alkalinity definition and common units used?

Answer 37

-Alkalinity is the capacity of water to resist acidification. -meq/L (milliequivalents per liter) -μeq/kg (microequivalents per kilogram) -mg/L CaCO3 (milligrams per liter of calcium carbonate)

Question 38

Conductivity definition and common units used?

Question 39

Salinity definition and common units used?

Question 40

Temperature definition and common units used?

Question 41

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

Answer 41

< 3 ppm stressful for most organisms. Below critical levels, life may not be present, or die-offs may happen

Question 42

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

Answer 42

Dissolved 02, C02 concentrations change throughout the day

Question 43

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

Answer 43

The increase in CO2 in the atmosphere leads to an increase in carbonic acid when CO2 falls as precipitation and enters lakes or oceans (lowers pH).

Question 44

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

Answer 44

phosphorus, Nitrogen, Sulfur and Calcium