Quiz 2 lecture 6

Question 1

How does oxygen concentration vary within a river network?

Answer 1

Low order streams will be cooler and more turbulent so increased oxygen, will also have light penetration and intermediate flow so macrophytes can attach

Question 2

Is there more intensive land use near bigger rivers or smaller streams? How does this impact nutrients?

Answer 2

more intensive land use near bigger rivers, this causes decreased oxygen in larger rivers as depth and width increase, water residence time increases, temp increases, and metabolic activity increases

Question 3

Is there more oxygen in summer or winter in a river reach?

Answer 3

more in summer, this is due to more organisms so more oxygen and also because ice cover in winter stops turbidity and amount of light coming in, if no ice cover than can be winter

Question 4

How does O2 change seasonally?

Answer 4

High DO is in january-may, cooler temp w out freezing over gives thi

Question 5

How does DO change episodically?

Answer 5

lower DO blips can happen due to algal blooms, big rain events can cause increases

Question 6

What is the uptake length in nutrient spirals?

Answer 6

Is where we will see nutrient in water column being uptake by food web, is the distance you could drop nutrient before it’s made way into food web

Question 7

What is the turnover length?

Answer 7

is distance that will be travelled until nutrient (organism) makes it back into water column

Question 8

What does a low spiraling length indicate?

Answer 8

higher nutrient retention (spends more time w out moving downstream), don’t spend as much time floating- get consumed and excreted right as away

Question 9

What does a high spiraling length indicate?

Answer 9

nutrient takes a while to get taken up, not much zooplankton so takes time to move up food web

Question 10

What are the reasons for high nutrient rentenion? (5)

Answer 10

is in high demand, low flow (less water movement so slow length), lots of attached biota which slows down spiral, high nutrient recycling rates, and have nutrient limitation

Question 11

What has more productivity, a longer spiraling length or a shorter spiraling length?

Answer 11

shorter spiraling length

Question 12

What are point sources?

Answer 12

confined/discrete, single source, highly regulated

Question 13

What are non point sources?

Answer 13

diffuse, they are linked to hydrological cycle, hard to measure and control

Question 14

In 1980s why did phosphorus decrease so much?

Answer 14

cause we treated the wastewater

Question 15

What do healthy phosphorus levels do to our rivers?

Answer 15

healthy balance between fish and plants

Question 16

What do unhealthy phosphorus levels due to our loading?

Answer 16

Phosphorus increases plant and algae growth, can lead to a decrease in O2 available and put organisms at risk

Question 17

What are the main sources of phosphorus?

Answer 17

wastewater treatment and plants effluent and storm water (in summer)etc