lab #7 paper final draft

Fatima SaavedraBiology Laboratory 142 Section 60

Benthic Macroinvertebrates Water Quality and Biodiversity in Raquette River and Woodstock

Pond

Fatima Saavedra, Breen Zachary, Hanna Gleason, Sanna Jaquith

Abstract

Biodiversity indices and biotic indices in benthic macroinvertebrates help predict the water quality and

the biodiversity that exists within a body of water. Many benthic macroinvertebrates can be classified as

being sensitive to pollution, semi-sensitive to pollution, semi-tolerant of pollution, and tolerant of

pollution. In this experiment, organisms were collected in order to analyze the diversity and water quality

of differing bodies of water. In this experiment, the water quality and biodiversity that was sampled was

from the Raquette River and the Woodstock Pond. In order to better analyze the indices, organisms were

collected and recorded on data tables according to their tolerance level. By using the benthic

macroinvertebrates tolerance, Hilsenhoff’s Biotic Index can be used to determine the water quality. The

biotic index in the river was 2.63 while the biotic index in the pond was 3.33. On the other hand,

Simpson’s Biodiversity Index analyzes the number of all individual species and each individual species in

order to determine which of the two bodies of water have a greater diversity. The biodiversity index in the

river was 25 while the biodiversity index in the pond was 7.13. According to Hilsenhoff’s Biotic Index

both water qualities were in the good range, although the biotic index in the pond was higher than the

biotic index of the river; however, in the Simpson’s Biodiversity Index, the river had the greatest

diversity.

Introduction


In this experiment we are using benthic macroinvertebrates as the bio indicators because they can’t travel

far and this causes them to be directly affected by the environment and its conditions (Wilhm R221).

Benthic macroinvertebrates are used widely because they are also easy to collect, they have different

tolerance levels, they live in the water most of the time, they are easy to identify, and they live for more

than one year. Biotic indices help predict the water quality within a body of water. These indices can then

determine whether the water quality is poor or excellent. The biodiversity index helps determine the

species diversity. Pollution within a body of water has been found to reduce species diversity-making the

body of water more suitable for pollution tolerant species. Biodiversity indices measure the chance that

two individuals randomly selected would be from the same species (Hilsenhoff 65). This measures the

biodiversity within a certain habitat-or in this case, body of water. Taking this into consideration, the

Raquette River would have the best water quality. According to our findings the Raquette and the

Woodstock Pond both had “good” water quality, but the biodiversity of the Raquette River was far greater

than the one for the pond. A greater biodiversity would mean that there were more species living in the

river than in the pond. This biodiversity index is saying that there are more species living in the river than

there are in the pond.

Materials and Methods

To begin the experiment one member of the team was designated to go in the river/pond (he or she wore

chest waders), and the other was designated to write/draw any of the organisms that surfaced (observer).

After deciding the roles, both members of the team headed down to the river. The team members noted

the conditions, the weather, and temperature of the day in order to better understand the culminating

factors in the organism’s habitat. The following week the same thing was done at the pond.

The member that went into the water jabbed four times with the net and scooped three times with

the net in order to make sure that there wasn’t too much mud in the dip net or to dislodge the organisms

from their respective homes. After that, the dip net was emptied into a bucket. Once this occurred the


member that went into the water transferred the contents of the bucket in to the sorting tray. The observer

wrote down/drew the approximate location and the terrain of the sampling site. Once in the tray, the

members of the team tried finding organisms that were recovered. The observer would then observe the

contents of the bucket that were collected by using a magnifying glass and forceps to investigate the

sample. Once an organism was found, the team members used forceps to put the organism in the petri

dish for further classification and identification. Afterwards the observer tried to identify the organism by

using the macroinvertebrate identification key and a magnifying glass. Then the observer drew

it/described it by writing/drawing all the information on that certain species down in their respective

laboratory notebook. Once the examination of all the organisms found was complete, the organisms were

was returned to the river or pond. This concluded the sampling of the first site.

After finishing the process for the first sampling site, the process would be repeated 4 more times

on the river/pond. After one location was taken care of, whether it was the pond or the river, the same

thing was done for the other following sampling sites. (If one started with the river, then the pond was

done afterwards and vice versa). After collecting all the data and writing all the species collected from

each sampling site (river or pond), the data was compared in order to find which sites water quality was

better.

Results


Woodstock Pond Raquette River0

0.5

1

1.5

2

2.5

3

3.5

3.332.63

Hilsenhoff's Biotic Index Score

Figure 1: Hilsenhoff’s biotic index score for section 60 class data. The difference between the indices is .7. A 2.6-3.5 biotic index score indicates the water quality is good.

Woodstock Pond Raquette River0

5

10

15

20

25

30

7.13

25

Simpson's Biodiversity Index

Figure 2: Simpson’s biodiversity index for Section 60 class data. The difference between indices is very large-with a 17.87 difference. A higher value indicates a higher biodiversity.


Woodstock

Pond Biotic Index

Woodstock

Pond Biodiversi

ty Index

Raquett

e Rive

r Biotic In

dex

Raquett

e Rive

r Biodive

rsity

Index0

5

10

15

20

25

3.337.13

2.63

25

3

7.29

36.56

Section 60 and Section 10 Class Data Comparison

Section 60 Class DataSection 10 Class Data

Figure 3: The class data for Section 60 and Section 10 is compared. In the section 60 class data, the biotic index in Woodstock Pond was slightly higher than the one from Section 10; similarly, the biodiversity index for Section 60 was a slightly lower than the one from Section 10, for Woodstock Pond. In the Raquette River the biotic index was slightly lower in Section 60; however the biodiversity index was significantly higher compared to Section 10.

Discussion

Table 1 shows all the benthic macroinvertebrate organisms that were found when the experiment was

conducted. From these numbers the biodiversity and the biotic index were concluded. The Raquette River

had a greater biodiversity according to Figure 2, but it had a lower biotic index score according to Figure

1. In contrast, Woodstock Pond had a higher biotic index score according to Figure 2, but it had a lower

biodiversity according to Figure 1. The water quality was “good” in both the Woodstock Pond and in the

Raquette River; however, the diversity was much higher in the Raquette River. This leads to the

conclusion that the Raquette River would have the best water quality because Hilsenhoff’s Biotic Index

accommodates both the Woodstock Pond and the Raquette River’s indices within the same range. When

the Section 60 data is compared to the Section 10 data, as seen in Figure 3, the data seems inconclusive


because the results contradict each other. Our team results in the experiment were practically non-

existent, and our class data offered better results; however when compared to Section 10 our data doesn’t

match up. In section 10 the biotic indices are the same, and they fall within the same range as Section

60’s data. Section 10’s biodiversity contradicts Section 60’s biodiversity. Even when Section 60 class

data was pooled, it was found that there were not many organisms that were detected, as seen in Table 1,

there were less than 50 organisms discovered. When there are more samples in an experiment, the less

likely it is to have skewed data. Section’s 60 data is inconclusive by itself because there were just not

enough organisms found to conclude which body of water had the best water quality. In order to gather

conclusive data an array samples, accurate taxonomy, and some system to convert invertebrate data into

water quality is needed (Lenat 279). During the experiment our data was pooled by discovering benthic

macroinvertebrates that were close to shore. There were other teams in the water as well. This could’ve

caused the organisms to hide in their habitat. Another possible reason to why our data was so skewed may

be because the technique used was not very effective. Benthic macroinvertebrates are organisms that help

determine water quality and the biodiversity within a body of water. The data found showed that many

aspects of this experiment can contribute to a source of error, whether it be a math calculation or a simple

discrepancy. The experiment could’ve been made better by not having so many people go in the water at

once or by having others go farther away from each other, and by learning a better technique to correctly

capture a benthic macroinvertebrate organism.

References

1. Wilhm J.L. 1970. Range of Diversity Index in Benthic Macroinvertebrate Populations. Water

Pollution Control Federation Vol. 42 No. 5: R221-R224.


2. Lenat D.R. 1993. A Biotic Index for the Southeastern United States: Derivation and List of

Tolerance Values, with Criteria for Assigning Water-Quality Ratings. Journal of the North

American Benthological Society. Vol.12 No. 3: 279-290.

3. William L. Hilsenhoff. Journal of the North American Benthological Society , Vol. 7, No. 1

(Mar., 1988), pp. 65-68

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