Biology 235, Fall 1997 -- Wetlands

Exam 2

Nov. 21, 1997 Name _____________________

Matching. Directions: in the blank next to each description below, write the letter of the matching term from the list of possible answers below. No term is used twice, not all are used. (2 pts. each)

1. ___ Indicator in mineral soils of wetland hydrology, even if macrophytes are absent

2. ___ Indicator in mineral soils of wetland hydrology, only if rooted macrophytes are present

3. ___ Soils with more than 20 to 35 percent organic matter

4. ___ Soils with less than 20 to 35 percent organic matter

5. ___ Technical term for soil with lots of peat

6. ___ Technical term for any wetland soil, either organic or mineral; opposite of "upland soil"

7. ___ Check this on a Munsell or similar chart; a number <2 is considered a wetland indicator

8. ___ An enzyme associated with anaerobic metabolism in plants

9. ___ Tissue associated with air circulation/gas exchange; has spongy texture

10. ___ Type of succession causing an aquatic ecosystem to eventually "fill in," become terrestrial

11. ___ Type of succession most widely accepted by wetland ecologists; suggests cyclical changes

12. ___ Not a type of succession, but a concept of wetland colonization/development

and disappearance across the landscape

13. ___ Type of photsynthesis often found in drought environments and some wetlands

14. ___ More nutrient/pollutant is entering wetland than leaving

15. ___ More nutrient/pollutant is leaving wetland than entering

Possible answers:

Multiple Choice: circle the letter next to the correct answer. (3 pts. each)

16. . Plants can readily use which form of Nitrogen as fertilizer?

a. molecular (N₂)

b. nitrate (NO₃)

c. amino acids

d. nitrogen in peat

17. Now one knows exactly, but about how long does it take for soil to change from upland to wetland soil?

a. a few days

b. a few weeks

c. 8-10 months

d. 8-10 years

18. Phosphorus is most likely to cause an algal bloom when...

a. It is organic

b. it is insoluble

c. the water is really well oxygenated

d. it is in the form of phosphate

19. A redox probe measures redox by...

a. comparing electrical potential (charge difference) through the soil between two metals

b. comparing the concentration of H⁺ ions in the soil

c. extracting any available oxygen molecules

d. measuring the ability of the soil to exchange cations

20. What is the ultimate cause of death of an upland plant when the soil is flooded?

a. Chlorophyll fades, plant can’t photosynthesize

b. DNA denatures in water

c. Plant dehydrates after root dies

d. Plant swells with water until it lyses (bursts)

Fill in the blank with the correct word(s). (1 pt. per blank)

21. Wetlands may help remove phosphorus, a serious water pollutant. Phosphorus is removed from the water when it is taken up by __________ which store it in their tissues. This may be only temporary, but if the dead tissues don’t decompose, the wetland builds a layer of ________ which can be a more permanent storage. The phosphorus can also _____________ to the soil particles, depending on how saturated those particles are; there must be a _________________ on the particles if Phosphorus is to be retained.

22. The two main stresses faced by Protists in wetlands are _______________ and _______________. Although structurally simple, Protists have a variety of _________________________ which allow their cells to withstand the unpredictable/stressful conditions.

Short Answer: provide a short list, one to several sentences of description, a diagram, etc.

23. (15 pts. total) Describe three (3) physiological stresses on a macrophyte growing in a wetland which are not normally found in upland environments. For each stress, what structural or physiological adaptations allow plants to successfully overcome the stress and grow?

24. (9 pts.) Describe three examples of animals that utilize wetland habitats, describing how each uses wetlands. Include at least one that is an "upland" animal; that is one that uses wetlands only occassionally, not really living in the wetland.

25. (4 pts.) Describe the "ecosystem development" of wetlands: in what ways are they "immature" or "mature" ecosystems?

32. (20 pts. total) Suppose you are evaluating a created wetland (marsh). In response to neighbor’s complaints, you go out to visit the site to assess its condition.

a. You notice a metal (iron) rod someone has stuck into the mud of the marsh. In the part of the rod above the mud, the iron is rusty (orange/brown colored). The part stuck in the mud is dark/black.

What is the relative redox condition of the orange and black parts of the metal (iron)? (4 pts.)

b. As you walk/wade through the marsh, you notice no "rotten eggs" odor.

What redox transformation causes with the development of the "rotten eggs" odor? (2 pts.)

c. Uh-oh, you forgot to bring your redox probe with you!! Based on the information given in parts (a) and (b), and the table below, can you at least suggest the range which probably contains the redox potential? Explain your reasoning. (4 pts.)

d. The engineer who built this wetland claims it will help remove nitrate pollution from the stream flowing through the marsh. Based on the preceding information, do you think redox conditions support nitrate removal? What exactly would be happening to the nitrate? (6 pts.)

e. The neighbors near the marsh had a cow die recently. They suggest that it was overcome by "swamp gas" or "marsh gas" and want your firm to compensate them for their cow. Your boss is pretty worried about this. What do you tell her: could gas from this wetland have killed the cow? Explain why or why not. (4 pts.)