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LIMNOLOGY
EXAM 3
May 3, 2005
There are 6 pages with questions totaling 164 points. The exam will be graded out of 150
points (14 points extra). Read each question carefully. Answer each question fully.
True-False, Word Choice, Multiple Choice, (2 pts each, 24 points total)
1. (True or False) Lakes with Clinograde dissolved oxygen profiles are unlikely to support cold
or warm water fish assemblages.
2. Diel variation in dissolved oxygen concentrations is expected to be greatest in the littoral
zone / pelagic zone of a eutrophic lake.
3. (True or False) A “clear water phase” in lakes is a good indication that top predators are
present.
4. Agriculture / Urbanization / Mining is the human activity that produces the greatest
nutrient loads to aquatic ecosystems in the US.
5. The “Middle-Out Hypothesis” argues that Alewifes / Bluegill / Gizzard Shad play a central
role in determining food web structure in the lakes where they occur.
6. (True or False) Biofilm in streams is comprised of both photosynthetic and heterotrophic
organisms.
7. (True or False) It takes nearly 12 months to convert CPOM to FPOM once it has entered a
stream.
8. (True or False) A P/R ratio less than 1 necessarily implies low levels of primary productivity
within the stream.
9. (True or False) The River Continuum Concept argues that stream invertebrate diversity
should increase in mid-order streams because these streams possess high levels of habitat
diversity.
10. (True or False) According to the RCC, most FPOM in mid-order streams comes from the
breakdown of CPOM in headwater streams.
11. (True or False) Most stream invertebrate species use FPOM as their dominant food source.
12. Which is the most likely P/R ratio for the typical, small stream in the Monongahela National
Forest? (Circle One)
0.1
1.0
3.0
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(60 points) Matching.
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2
3
4
5
% tolerant
allochthonous
Alosa sp.
Anabaena
Asplanchna
autochthonous
26
27
28
29
30
31
eutrophication
flocculation
Flood Pulse Concept
functional feeding group
G. E. Hutchinson
Glossosomatidae
52
52
53
54
55
56
Pyrrophyta
retentiveness
Riverine Productivity Model
rotifers
S. R. Carpenter
Serial Discontinuity Concept
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7
8
9
10
11
12
Baccillariophycae
Baetidae
bioassessment
biofilm
biomanipulation
Chaoborus
32
33
34
35
36
37
grazers
Huryn and Wallace
Hydropsychidae
integumental respiration
Intermediate Predator Hypothesis
McQueen
57
58
59
60
61
62
setae
shredders
Simuliidae
Size-efficiency hypothesis
Size-selective predation
tracheal gills
13
14
15
16
17
18
Chrysophycae
clear water phase
clinograge
Clupeidae
collectors
coronal cilia
38
39
40
41
42
43
Meyer and Edwards
microcrustacea
mixotrophic
mucilagenous sheath
nutrient loading
nutrient loading
63
64
65
Vanni
WVSCI
zooplankton
19
20
cyclomorphis
Daphnia
21
22
23
Desmids
DeVries
Dinobryon
24
EPT taxa
44
45
46
47
48
49
orthograde
parthenogenesis
photo-inhibition
phytoplankton
piscivore
planktivore
50
Pteronarcydae
25
an alternative to the RCC, which states that large rivers are strongly dependent on sources of
energy from the surrounding floodplains
group of true green algae
change in body form of zooplankton over successive generations
group of zooplankton that are among the smallest multicellular organisms on earth
family of stoneflies that are important shredders
form of gas exchange that occurs across the body cavity, used by most zooplankton
negative scoring metric in WVSCI
multimetric index of biological condition
golden algae
explanation for why average zooplankton size increases when planktivorous fish are absent from a
lake - based on increased predation of small zooplankton by Chaoborus
consumer that eats fishes
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Physical, chemical, and biological response of an aquatic system to high nutrient loading rates
managing piscivore populations to reduce phytoplankton blooms and hypereutrophic lakes
classification of stream invertebrates on the basis of what and how they eat
species of midge, aka "Phantom Midge"
nutrient loss to the hypolimnion and high grazing rates combine to produce a period of
exceptionally low algal biomass in stratified ponds and lakes
organism that is able to both photosynthesize and take up dissolved organic matter
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
Increase in nutrient concentrations in a water body over time
distribution of dissolved oxygen with depth often observed in eutrophic lakes
fish species that is an important consumer of zooplankton in lakes
an alternative to the RCC, which states that large rivers are strongly dependent on sources of
energy from local photosynthesis
structural feature of cyanobacteria that makes them difficult to eat
autotrophic dinoflagellates
group of stream insects comprised of mayflies, stoneflies, and caddisflies
explanation for why average zooplankton size decreases in the presence of planktivorous fish
used by aquatic insects in gas exchage between their body and surrounding water
stream ecologists that found that floodplains are important sources of organic matter to large rivers
limnologist that determined that increased nutrients and decreased grazing rates were responsible
for producing increased phytoplankton growth when planktivorous fish are present
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Discussion (give details to receive full credit)
1. (26 points) Describe the physical, chemical, and biological changes that occur as a lake
transitions from an Oligotrophic to Mesotrophic to Eutrophic state. Discuss in terms of:
Water clarity
Secchi depth Nutrients
O2 in hypolimnion
Primary productivity
Phytoplankton diversity
Fish productivity
Fish community structure
Value as a fishable resource
Diel O2 Variation
Aquatic plants in the littoral zone
Occurrence of fish kills
Value for contact recreation
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2. (10 points) We discussed 5 key characteristics of lakes that indicate that predation is an
extremely important force structuring lake ecosystem dynamics. What are they?
3. (12 points) Greig and McIntosh (2006) argued that small shredders increase in trout streams
because they are released from competition with larger shredders that are vulnerable to fish
predation. This explanation is identical to the “size-efficiency” hypothesis of Brooks and
Dodson (1965). What is an alternative to the size efficiency hypothesis? How can it be
applied to the shad / zooplankton interaction described by Brooks and Dodson (1965), and
how could it be applied to the trout / shredder interaction described by Greig and McIntosh
(2006)?
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4. (8 points) Define a trophic cascade and list the 2 key conditions that must be met for a
trophic cascade to occur.
5. (24 points) You have been called as an expert witness in a court hearing over the potential
impacts of Mountaintop Mining / Valley Fill to the health and productivity of larger rivers
downstream. The argument is that the loss of headwater function through mining impacts
will cause a measureable impact to larger river food webs. Based on what you have learned
in this class, discuss the theoretical basis for this argument, the scientific evidence in
support of this argument, and the potential (and evidence) that this argument may be
incorrect.
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