Name
LIMNOLOGY
EXAM 3
May 3, 2005
There are 17 questions on 6 pages worth a total of 160 points. Read each question
very carefully, answer each question fully, and allocate your time accordingly.
1. (2 pts) (True or False) Blue-green algae are eukaryotes.
2. (2 pts) (True or False) A lake that exhibits a metalimnetic maximum in chlorophyll a
concentration typically is dominated by blue green algae.
3. (2 pts) (True or False) The best explanation for the “Paradox of the Plankton” is that
resources, such as nutrients, are so variable over space and time in lakes that no
single species of algae is able to out-compete others.
4. (2pts) (True or False) The “clear water phase” in lakes is produced by a pulse of
acidity from snow melt.
5. (2 pts) (True or False) Crustose and Prostrate are the two most common growth
forms of periphyton in streams.
6. (2 pts) (True or False) It generally takes less than three months to convert CPOM to
FPOM once it has entered a stream.
7. (4 pts) (Circle all that apply) The following are NOT characteristics of blue green
algae:
a. Ability to fix nitrogen
b. Ability to photosynthesize at low light levels
c. Mesotrophic
d. Produce alkaline phosphatase
e. Produce nitrogenase
f. Lack a nuclear membrane
g. Occur in three different body forms
h. Most common in oligotrophic lakes
8. (2 pts) (Multiple Choice) A lake that is dominated by Desmids is most likely:
a. Oligotrophic
b. Mesotrophic
c. Eutrophic
9. (4 pts) (Circle) Under good conditions, a female diploid cladoceran will produce a
haploid / diploid egg that develops into a male / female adult.
1
10. (6 pts) (Short Answer) List and briefly describe the three distinct suborders of
copepods.
11. (6 pts) (Short Answer) What is the purpose for cladocerans shifting to sexual
reproduction under “poor” environmental conditions (e.g., low amounts of food and
high predation levels)?
12. (8 pts) (Short Answer) Briefly describe how bottom-up and top-down forces interact
to produce a pulse of increased lake phytoplankton abundance in fall.
13. (12 pts) (Short Answer) Briefly describe / illustrate the “Intermediate Predator
Hypothesis” and its relation to fish – zooplankton interactions in lakes and ponds.
2
14. (12 pts) (Short Answer) Briefly describe / illustrate the pathways by which FPOM in
streams is produced from dissolved organic matter (DOM), coarse particulate
organic matter (CPOM), and light / periphyton.
15. (12 pts) (Short Answer) Fill in the table to describe the physical and biological
characteristics of headwater, mid-order, and large river stream reaches expected
given the Classical View of the River Continuum Concept.
Characteristic
Narrow, Wide, or Very Wide
Shallow or Deep
Clear or Turbid
Light (low or high)
Retentiveness (low or high)
P / R (low or high)
NDM (neg. or pos.)
CPOM:FPOM (very low, low, or high)
Shredders (low or high)
Grazers (low or high)
Filterers (low or high)
Invertebrate Diversity (low or high)
Small Stream
Narrow
Mid-Order
Wide
Shallow
Large River
Very Wide
High
low
3
16. (12 pts) The following graph shows how P/R ratios vary in a small stream in the Mon
National Forest over the course of a year.
1.8
1.6
P/R Ratio
1.4
1.2
1
0.8
0.6
0.4
0.2
0
jan
feb mar apr may jun
jul
aug sep
oct
nov dec
Month
a. During what month(s) is this stream considered autotrophic? Heterotrophic?
b. What could cause the high P/R ratio in spring and the reduced P/R in summer?
c. What could cause the secondary spike in P/R in fall?
4
17. (70 pts) Match each word to its appropriate definition (there are more words than
definitions, words are used only once).
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
allochthonous
Alosa sp.
Anabaena
Asplanchna
autochthonous
Baccillariophycae
Baetidae
bioassessment
biofilm
biomanipulation
Chaoborus
Chrysophycae
collectors
cyclomorphis
Daphnia
Desmids
DeVries
Dinobryon
EPT taxa
flocculation
Flood Pulse Concept
functional feeding group
G. E. Hutchinson
Glossosomatidae
grazers
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Huryn and Wallace
Hydropsychidae
McQueen
Meyer and Edwards
microcrustacea
mixotrophic
mucilagenous sheath
parthenogenesis
% tolerant
photo-inhibition
phytoplankton
piscivore
planktivore
Pteronarcydae
Pyrrophyta
retentiveness
Riverine Productivity Model
rotifers
S. R. Carpenter
Serial Discontinuity Concept
setae
shredders
Vanni
WVSCI
zooplankton
stream invertebrates that feed on CPOM
an alternative to the RCC, which states that large rivers are strongly dependent on sources
of energy from the surrounding floodplains
stream invertebrates that feed on periphyton
family of caddisflies that are important grazers
organic matter in streams that originated within the stream itself
family of caddisflies that are important collector-filterers
capacity of a stream to store organic matter so that it can be processed locally
autotrophic drifting organisms
limnologist that argued that top predators do not have an effect on phytoplankton
communities, because of the high variability in planktivorous fish and zooplankton
communities
group of stream insects comprised of mayflies, stoneflies, and caddisflies
consumer that eats plankton
an alternative to the RCC, which states that gradual changes along a river continuum are
disrupted by regular inputs of sediments, water, and organic matter from tributaries
limnologist that determined that increased nutrients and decreased grazing rates were
5
responsible for producing increased phytoplankton growth when planktivorous fish are
present
conversion of DOM to FPOM through mechanical attachment
stream invertebrates that feed on FPOM
organism that is able to both photosynthesize and take up dissolved organic matter
consumer that eats fishes
change in body form of zooplankton over successive generations
stream ecologists that determined that differences among stream habitats (e.g., pools and
riffles) were as important to organic matter sources and functional feeding groups as
differences among small and large streams
group of true green algae
limnologist that proposed the "Middle-Out" hypothesis as an alternative to the "Trophic
Cascade" hypothesis
organic matter in streams that originated in the surrounding watershed
classification of stream invertebrates on the basis of what and how they eat
structural feature of cyanobacteria that makes them difficult to eat
combination of attached algae, bacteria, and fungi attached to the surface of rocks and
wood in streams
limnologist well known for his 1961 paper on the "Paradox of the Plankton"
form of asexual reproduction found in rotifers and cladocerans
common species of chrysophycae
managing piscivore populations to reduce phytoplankton blooms and hypereutrophic lakes
golden algae
species of midge, aka "Phantom Midge"
species of rotifer, aka "Bag-O-Guts"
group of zooplankton that are among the smallest multicellular organisms on earth
stream ecologists that found that floodplains are important sources of organic matter to
large rivers
6