StreamEcology:
CorrelatingtheEffectsofPollutionon
MacroinvertebrateDiversity[1]
Jayanth (Jay) Krishnan
T.A. Ms. Bianca Pier
Lab Partner and Assistance Provided by
Ms. Catherine Mahoney
Section 1: Biology
November 16th, 2011
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Introduction/Purpose:
Why Did We Study This Problem?
Benthic macroinvertebrates are organisms without a backbone that dwell in the bottoms
of the water bodies they live in. They are typically visible to the naked eye. Additionally, they
live in a habit continuously over an extended period of time. In this lab, we identified several
species especially benthic macroinvertibrates. We studied these species with regard to their
pollution sensitivity in streams with differing water quality. The streams we studied were
Kromme Kill located in Menands, New York and Fox Creek located in John Boyd Thacher State
Park. The following streams were chosen for this experiment as they were different sources of
water; differing in the amount of pollution. We choose to study benthic macroinvertebrates as
they known to be very sensitive to sporadic changes and seasonal variation. Additionally, they
are fairly easy to collect. [3]
Of the studied organisms, the benthic macroinvertebrates are the most sensitive to
pollution. The organisms are regarded by scientists as bio-indicators as their presence is
indicative of whether or not the quality of the water they live in is suitable or clean. This is
because benthic macroinvertebrates have different tolerances to pollution. With this information
we know that if an organism is highly sensitive to pollution, then fewer of those organisms will
exist in a highly polluted body of water. In contrast, organisms that are relatively insensitive to
pollution may exist in astronomical numbers despite the fact that the water bodies they live in are
polluted. [3]
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[Reference 1] Lab Report was written according to the guidelines of the rubric
The species that are most sensitive to pollution are those in the taxi Ephemeroptera,
Plecoptera and Trichoptera (EPT). The only organism that was highly sensitive to pollution was
the stonefly (which belongs to the Plecoptera order, mayfly and caddisflies (case-building).
Scientists use to test the quality of a stream by calculating an EPT index which is the proportion
of organisms in these three taxi. The most pollution tolerant organisms are the blackfly larva, the
bristleworm, the flatworm, the leech, the midge larva, the roundworm and the snail.
The reason why macroinvetebrates were studied and the purpose of this lab was that
macroinvertebrates are helpful in determining whether pollution affects the number
macroinvertebrates present in a body of water. As stated earlier, organisms from two different
sources of water were obtained and studied. One source of water, the Kromme Kill, is
hypothesized to be highly polluted, while the other source of water, Thacher Park, is
hypothesized to be relatively un-impacted. Therefore, macroinvertebrates were to be collected
separately from each different source of water, and data was combined from each group in the
class and then data from all classes were pooled together. I hypothesized that by obtaining
different macroinvertebrates found in each source of water, that pollution will indeed have an
impact with regard to affecting the proportion of macroinvertebrates found in a body of water.
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Materials and Methods
What did we do? How did we do it?
Ms. Bianca Pier, our lab TA, collected the macroinvertebrates that were used in this
experiment by using a kick-net approach. More specifically, a tool called a Surber fauna bottom
sampler was used. The Surber fauna bottom sampler is a net fastened to an L-shaped metal
frame which is secured in the streambed. The next step is to place a kick-net snugly against the
streambed in a riffle facing upstream. The sample area, proportional to the net’s size, is then sent
to be directly in front of the net. Large gravel, cobble and boulder and rocks that occupied our
chosen sample area is then scrubbed roughly 10 meters upstream into the kick-net so that the
organisms (macroinvertebrates), and other materials materials on the rock would flow inside the
net. Sand, smaller rocks, along with other bottom sediments were disturbed and collected by the
shuffling of feet in the desired sample area. [1]
Once our sample was collected, it was transferred to a bucket, and the kick-net placed
over it was turned inside out. The TA then pushed the kick-net far into the bucket. She then
used stream water to rinse out all the contents collected in the kick-net into a bucket that had a
volume of five gallons.
For our experiment, as stated in the introduction, our samples were collected from two
streams. The first stream is named Kromme Kill - a stream located in the greater capitol region.
This stream flows through Loudonville and Menands, New York. In this journey it passes
through the Albany Rural Cemetery. Eventually, the stream is emptied into the Hudson River.
The other stream that samples were taken from was Fox Creek from John Boyd Thacher State
Park. [1]
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Now with our samples collected we needed to identify our macroinvertebrates. Hence we
first poured a sample from one stream into a pan. Next, we took a bit of the sample from the pan
and poured into a petri dish and viewed the sample under a dissecting microscope. Then using
peer reviewed literature (Textbooks, books, articles form the internet) and documents (pre-lab
materials) that were given to us, we could identify the macroinvertebrates. The quality of our
samples and the stream were assessed using several measurements. One such measurement is
provided by the Shannon- Winer Index, which measures diversity using the following formula: H
= -∑pilnpi
In this formula H represents the Diversity Index and pi = proportion of individuals in the
total sample belonging to the ith species. The Index is quite significant and useful due to the fact
that index takes both richness and evenness into account regarding the stream populations. Using
this formula we know that a large H value is correlated with more unpredictability (not due to
chance) regarding the chance of the next individual drawn being the same as the previous one.
In other words, a stream with a large H value has great diversity, whereas a stream with a small
H value has low diversity.
Another measurement that was used in this lab to measure the evenness of a population
was the Evenness Index. By evenness, this measurement tells us whether different species appear
in relatively similar proportions. The Evenness Index is calculated using: J = H/lns
In this formula J represents the Evenness, H still continues to represent the diversity
Index and s represents the number of species present.
The last measurement used was the EPT Index which looks at the abundance of
organisms from the orders Ephemeroptera, Plecoptera and Trichoptera using the following
formula: EPT Index = ∑(EPT / total # organisms) * 100% The significance of the Index is that
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there is no significant differences between the H and J values of streams. This value suggests, but
does not prove, that one stream has better water quality than the other. Nevertheless the EPT is
primarily viewed as a means of assessment to the everyday Ecologist. [3]
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Results: Figures and Tables
Table 1: Data for section 1: Total number of organisms in Fox Creek
and Kromme Kill. This table can compare the diversity side-by-side
Taxon
FOX
KROMME
Odonata - Dragonflies, damselflies
3
0
Ephemeroptera - Mayflies
9
0
Plecoptera- Stoneflies
46
5
Trichoptera - Caddisflies (case-building)
2
2
Trichoptera - Caddisflies (net/free-living)
2
7
Hemiptera - Bugs
2
1
Diptera - Fly larvae, flies
43
6
Diptera - Chironomidae - Midges
2
2
Coleoptera - Beetles
2
1
Megaloptera - Dobsonflies
0
0
Decapoda - Crayfish
0
0
Amphipoda - Amphipod crustaceans
0
2
Isopoda - Sow Bugs
0
2
Gastropoda - Snails
2
0
Nematoda - Round Worms
0
0
Annelida -Segmented Worms
1
2
Arachnida - Spiders
5
0
Collembola - Springtails
1
0
Maxillopoda - Copepod crustaceans
0
5
Platyhelmenthes - planaria
0
0
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Table 2 (A&B): The tables represent the total number of organisms for all BIOL1010 classes. It also displays the average number of organisms. Additionally, all
the H, J and EPT Index values for each BIOL-1010 class as well as the average H,
J and EPT Index values for all the classes are calculated and inputted. P-values
resulting from the T-tests for the H, J and EPT Index values as well as the
conclusion drawn from the P-values are also displayed
Table 2A: Values for all Biology 1010 labs of Fox Creek
# Species
# Organisms
H
J
EPT Index
01 -Bianca
13
120
1.6435
0.6407
47.5
01 - Payel
10
90
1.8177
0.7894
66.7
02 - Shounak
14
78
1.7762
0.6730
61.5
02 - Pranav
12
92
2.1489
0.8648
47.8
16
51
2.3760
0.8876
27.5
04 - Matt
11
80
1.8096
0.7547
53.8
05 - Kristen
9
59
1.6084
0.7320
67.8
05 - Keith
9
51
1.8244
0.8303
31.4
11.8
77.6
1.8756
0.7716
50.50
Section
04 - Jake
Miner
Averages
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[Reference 1] Lab Report was written according to the guidelines of the rubric
Table 2B: Values for all Biology 1010 labs of Kromme Kill
Section
# Species
# Organisms
H
J
EPT Index
01 -Bianca
11
35
2.2011
0.9179
20.0
01 - Payel
10
48
2.0864
0.9061
0.0
12
84
0.8697
35.1
02 Shounak
02 - Pranav
2.1611
12
84
2.1936
0.8828
11.9
10
64
2.1024
0.9131
34.4
04 - Matt
10
69
2.2044
0.9573
24.6
05 - Kristen
11
36
2.0437
0.8523
38.9
05 - Keith
7
30
1.8155
0.9330
26.7
10.4
56.3
2.1010
0.9040
23.94
04 - Jake
Miner
Averages
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[Reference 1] Lab Report was written according to the guidelines of the rubric
50
45
40
35
30
Number of
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organisms
20
15
10
5
0
[Reference 1] Lab Report was written according to the guidelines of the rubric
Plecoptera- Stoneflies
Diptera - Fly larvae, flies
Ephemeroptera - Mayflies
Arachnida - Spiders
Odonata - Dragonflies,…
Gastropoda - Snails
Coleoptera - Beetles
Diptera - Chironomidae -…
Hemiptera - Bugs
Trichoptera - Caddisflies…
Trichoptera - Caddisflies…
Collembola - Springtails
Annelida -Segmented Worms
Platyhelmenthes - planaria
Maxillopoda - Copepod…
Nematoda - Round Worms
Isopoda - Sow Bugs
Amphipoda - Amphipod…
Decapoda - Crayfish
Megaloptera - Dobsonflies
Table 2C: Statistical Tests and Conclusions:
Species Count in the Fox Stream and Kromme Kill
Fox
Kromme
Species
Figure 1: Bar graph illustrating a comparison between the numbers of
macroinvertebrates identified for each taxi in the Kromme Kill and Fox
Creek samples for BIOL-1010 Lab Section 1
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