final exam review Flashcards
Water is the only natural substance found in __________________ on planet earth.
all three states of matter at temperatures normally found on
Viscosity
Resistance of fluid to a change in shape or flow
Density
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
What is the Epilimnion?
is the top-most layer in a thermally stratified lake.
-Warmer
- typically has a higher pH and;
- higher dissolved oxygen concentration than the hypolimnion.
What is the Thermocline?
Region where temperature, and density change rapidly resulting in lake stratification.
-The point at which is occurs is the Thermocline
What is the Hypolimnion
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.
,
What is a limiting factor for aquatic life?
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.
What are the common gases found in the atmosphere?
Nitrogen (N2)
Oxygen (O2)
Carbon Dioxide (CO2)
What is the Influence of temperature in regards to dissolved gases?
As temperature increases, the solubility of oxygen decreases.
What is the Influence of salinity in regards to dissolved gases?
As salinity increases, solubility of oxygen decreases.
How is oxygen added to a waterbody?
1.) Absorption across the air-water interface (turbulence helps)
2.) Flowing systems often receive O2 from groundwater
3.)Photosynthesis (respiration)
The amount of dissolved oxygen that can be held by water depends on?
water temperature
salinity
pressure
Natural limiting nutrients include?
Phosphorus, Nitrogen, Sulfur and Calcium.
What is Eutrophication?
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
What is Salinity?
Concentration of salts in water
True or False : Suspended solids can impact turbidity and temperature?
True!
Lentic: derived from the Latin word “Lentus” which means “slow or motionless”
Lentic systems include:
Lentic Systems=
ponds, lakes, swamps, marshes etc
Lotic: derived from the Latin word “Lotus” which means “washing”
Lotic Systems Include:
Lotic systems =
streams and rivers
When is water the most dense?
Most dense at 3.9º C
- This is when water molecules are closest together, resulting in the highest mass per unit volume.
When is water the least dense?
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.
Describe the relationship between water temperature and density?
The relationship between temperature and density are what causes seasonal changes in lake stratification.
What is Viscosity?
Viscosity is the:
resistance of fluid to a change in shape or flow.
How does the viscosity of water affect aquatic life?
- Allows some organisms to be buoyant
- Dictates movement of planktonic organisms & and particles.
-All because water is so dense.
What is the light compensation level?
Light compensation level =
- depth where 95% - 99% of light is extinguished.
What is the light compensation level? How does this affect aquatic life at different water depths?
-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
Most photosynthesis occurs in which zone in regard to water depth?
Euphotoic zone
What are 3 factors that impact the concentration of dissolved gases in water?
1.) Temperature
2.) Pressure
3.) Salinity
Describe the relationship between water temperature and density? but simplify it
- 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.
__________ is the most important gas that impacts aquatic life
Oxygen
Is there more Dissolved Oxygen in saltwater or freshwater? Why?
Freshwater holds more oxygen than saltwater.
- as the salinity of water increases, the capacity of the water to hold dissolved oxygen decreases.
What are 2 ways that DO is added to waterbodies?
1.) Photosynthesis
2.) Diffusion from the Atmosphere
Dissolved Oxygen definition and common units used?
- 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.
Dissolved Carbon dioxide definition and common units used?
- 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.
pH definition and common units used?
- 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.
Total Dissolved Solids definition and common units used?
- 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).
Turbidity definition and common units used?
- Turbidity is a measure of the cloudiness or haziness of a fluid, usually water.
-Nephelometric Turbidity Units (NTU)
Alkalinity definition and common units used?
-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)
Conductivity definition and common units used?
Salinity definition and common units used?
Temperature definition and common units used?
What are the critical levels of DO, pH for freshwater fish?
< 3 ppm stressful for most organisms.
Below critical levels, life may not be present, or die-offs may happen
Why might it be important to measure DO, pH and CO2 during the day and night?
Dissolved 02, C02 concentrations change throughout the day
How can the concentration of CO2 in the atmosphere impact acidity of lakes and rivers?
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).
What are 4 nutrients that are often limiting in aquatic ecosystems (in limited supply)
phosphorus, Nitrogen, Sulfur and Calcium
