Quiz 2 Lecture 2 Flashcards
What three things can happen when light interacts with water?
It can absorbed- Converted to heat
Transmitted- Goes to deeper layers of the water
Reflected- goes back to the atmosphere
Why are absorbance and transmittance plots in the opposite direction?
what is not absorbed gets transmitted
In pure water what wavelengths get absorbed? What wavelengths get transmitted?
Longer wavelengths (red-orange) will get absorbed, shorter wavelengths (purple-blue-green) will get transmitted.
What impacts lakes color in terms of light?
The wavelengths of light that are transmitted
Are aborsbance and transmission curves the same in all water bodies?
No, for example if a lot of algae which has pigments that absorb more blue and red, lake can look a lot more greener- more green wavelengths transmitted
Different plant pigments have what kind of different rates of absorption?
they have diff absorption percentages for diff wavelengths
How does photosynthesis rates vary with different wavelengths?
as wavelengths not absorbed by certain plants pigments, photosynthesis rate decreases
How does clarity of water impact photosynthesis?
it will impact how much radiation will be transmitted to different depths and what wavelengths are being transmitted which will impact primary production in the water- for example if a bunch of algae on top for chlorophyll A, radiation may not be transmitted, and red wavelengths of light may not be transmitted as their already absorbed stopping plants at the bottom from absorbing that wavelength and reducing photosynthesis.
The colour of a lake we see is the result of what?
Of what is in the water, particles and dissolves substances will impact how deep the water will penetrate and the wavelengths absorbed/transmitted/scattered
Lake colour depends on the interaction between?
Apparent colour (some wavelengths absorbed, others and transmitted and then scattered) and real colour (the color of the stuff in the water).
What are the physical indicators of water quality? (6)
Total dissolved solids
Conductivity
Total Suspended Solids
Turbidity
Water Colour
What are the chemical indicators of water quality?
pH
* Biological Oxygen Demand
(BOD)
* Dissolved Oxygen (DO)
* Hardness
* Total Nitrogen
* Total Phosphorus
* Heavy metals, pesticides, toxic
substances
What are the biological indicators of water quality?
Bacterial content: E.coli,
Coliform bacteria
* Ephemeroptera
* Plecoptera
* Trichoptera
* Community composition
metrics
* Diversity indices
* Dominance of pollution tolerant
organisms
What indicators do we start with?
Biological indicators bcuz they need low level equipment, then move onto the others
Is the distinction between dissolved and particulate matter arbitrary? What else is it referred to?
Yes, usually defined based on their ability to pass through a filter (can be 0.5-1 um)
other thing it is referred to colloidal and gravitoidal (larger due to settling down due to gravity)
What are Total dissolved solids?
mass of material (inorganic and organic) dissolved
in water, usually measured in ppm.
What’s the ideal range of tds for drinking water? What is the threshold?
0-50 ppm, as u go up more tds (average tap water), near 0 is the closer u are to pure water. Often 2 um.
What is conductivity?
Relative amount of electricity that can be conducted by water
Is pure water very conductive? What makes it more conductive?
No, but as we get more ions then more conductive, is why seawater is more conductive but distilled water not.
What is specific conductance? Why do you have this?
conductivity measure corrected to
25°C to allow for comparison between reported measures of
conductivity, this is because temperature impacts conductivity so it’s just to standarize it
How are conductivity and TDS related? Why do we use conductivity metre field?
conductivity is only impacted by ions that can conduct, TDS is all particles. We use conductivity as proxy of what’s in water bcuz TDS hard to measure.
What is TSS?
dry weight of particles trapped on a filter paper, don’t make it through filter