What's wrong with this picture?
Two of your classmates get bored and decide to sword fight with a probe and the transparency tube. Is this okay to do while they are waiting for instructions?
No! Our gear is delicate and sometimes expensive. We need to treat it all carefully and with respect and let an instructor know if it isn't working properly.
How do we measure depth?
Using a meter stick in the water, measured in centimeters (cm).
If water is moving swiftly, we say the stream has a high ________.
flow rate
How could a large population of bottom feeders affect the transparency of the water?
Bottom dwellers kick up sediment from the riverbed, resulting in lower transparency/higher turbidity.
What happens to the organisms in water if pesticides find their way into the stream?
They can be poisoned and die off.
Your teacher decides to help us take a transparency measurement. They scoop water into the transparency tube until the secchi disk disappears while standing in the sunshine. What is wrong with this process?
Sunlight alters the transparency reading. We measure this parameter in the shade.
What units do we use to measure transparency?
centimeters (cm)
Thermal pollution can have harmful affects because it may alter a stream's ________.
temperature
The fertilizer runoff would increase nitrate concentration.
What could happen to algae populations if the water is showing high levels of nitrates?
The algae populations could explode and then die off dramatically.
Miles decides that, since it's a hot day, he is going to splash around in the water before taking a transparency measurement. Why is this a bad idea?
Miles could kick up sediment, making the transparency appear lower than it usually is.
What tool do we use to measure dissolved oxygen (DO)?
a DO probe
This is the parameter we use to predict how much water is at a site.
depth
How can a high turbidity (low transparency) measurement help you predict the temperature of the water?
Highly turbid water has a lot of floating particles that absorb heat, often making the temperature of the water higher.
What could happen to the diversity of organisms in a river if dissolved oxygen decreased due to rising temperatures.
The number of different organisms that could survive in the river would decrease.
Jeanette is taking a nitrate measurement. She sticks the probe in the water, takes it out of the water, and then reads the number. What did they do wrong?
What are the units we use to measure nitrate concentration?
milligrams of nitrates per liter of water (mg/L)
A secchi disk is a tool used to measure _________.
transparency
An industrial plant upstream dumps hot wastewater into a nearby river. How would the dissolved oxygen be affected by this?
Hot water can hold less dissolved oxygen than cold water, so the dissolved oxygen would most likely decrease.
A housing development decided to dig out a river bed, making it deeper to avoid flooding. How could this affect what can live there?
Answers may vary.
examples:
Deeper water is better for larger organisms.
Shallow water is better for egg-laying -> may decrease fish populations
Deeper water can have less nutrients and DO, limiting the organisms that can survive.
A student says that dissolved oxygen measures all of the oxygen atoms in water (H2O). What's wrong with this statement?
DO measures the concentration of O2 (elemental oxygen) that is dissolved in water, not the oxygen atoms captured in water molecules.
about 0.7 m/s
What parameter might be best for determining a stream's risk of eutrophication from too much agricultural runoff?
nitrates
DO and transparency would decrease, due to the high level of dead organic matter decaying in the water, and temperature would increase due to the high turbidity.
Why might a dam slowing the flow rate and increasing depth of a river be harmful for fish living in the water there?
Answers may vary.
examples:
Slower flow rate and deeper water can decrease DO, decrease temperature, decrease nutrient concentration.
Fish like to lay eggs in shallower water.