Abstract
The abundance and distribution of microfauna found associated with
Prionitis lanceolata at a point chosen to represent an unpolluted, natural
environment. The results of this study were compared to the results of a
previous study made in the Pt. Pinos area. Also, areas at Pt. Pinos uere
resampled to determine the effects of seasonal variation on microfaunal
communities. Results indicate that differences in microfaunal community
structure observed at Pt. Pinos are greater than those attributable to
the effects of natural variation. Seasonal varistion uas found to have
little effect in the Pt. Pinos area. From these results a hypothesis for
testing for pollution damage in an area uas formulated.
2.
Introduction
Uhile noticeable differences in numbers of species and diversity
indices uere found to exist in the microfaumal communities associated with
the three species of algae examined around the polluted portion of Pt. Finos
(Clearman, 1970), the role of the effluent in causing these differences may
not be clearly stated until more is knoun of the natural variation in com-
munities of this type. It is possible that the observed differences fall
within the general range of natural variation along the point. In order to
provide an ansuer to this question, a study similar to the survey at Pt.
inos (Clearman, 1970) uas undertaken at another area chosen to represent
an unpolluted, natural environment. This area is an unnamed point, hereafter
referred to as Point 42, that lies approximately 1000 meters south of Pt.
Pinos. The point is approximately 2/3 the length of Pt. Pinos, but is of a
similar conformation, and maintains the general Nu orientation of Pt. Pinos.
Uave action at the tuo points is roughly comparable, although Pt. Pinos
may recieve slightly heavier wave action at times.
By studying algal-microfauna associations on this point, it uas hoped t
see hou natural communities compared with those previously observed at Pt.
Pinos, thus allowing a firmer statement to be madelofthe effluents effect
on the communities studied.
Also, key areas, as revealed by the original survey at Pt. Pinos, uere
resampled to determine the composition of the communities after a tuo month
interval to see hou they compared to the results of the first study carried out
during the spring.
3/
Materials and Methods
Prionitis lanceolata was the alga selected for study because it's
associated microfauna shoued the most marked effects near the outfall.
Ten stations (areas) were sampled around Pt. 42 with three replicates made
at each area (Fig. 1). The samples were analyzed in themanner previously
described (Clearman, 1970). Again, the Simpson andshannon-leiner indices
uere used to compute values for species diversity.
At Pt. Pinos four key areas in the vicinity of the outfall (areas 4, 5,
and 7) and areas at the end of the point (area 10) and directly across
from the outfall (area 12) were resampled (Fig. 3, Clearman, 1970). Sample
analysis was carried out as befors (Clearman, 1970).
The results of the original study, the summer resamples and the samples
at Pt. 12 uere compared in terms of numbers of species present and the diversit
indices.
In order to statistically compare areas felt to be polluted with natural,
unpolluted areas, the data was divided into three groups. Pt. Pinos was divided
into tuo groups designated "polluted", composed of arsas felt to be heavily
damaged, as shoun by lou values for the diversity indices and the small number
of species found, and Funpolluted", consisting of the remaining areas around
the point. These tuo groups and Pt. 42 (all areas) were compared by employing
the Student's t test, using the mean values and standard deviations of the
species diversity indices and the number of species of the three groups.
Finally, the "unpolluted" group at Pt. Pinos and the areas of Pt. 42 uere
randomly divided into equal groups and compared by the Student's t test, as
above, to test the internal variability of the three criteria tested.
Results
Et. 42 The tabulated data for the samples at this point are shoun in
Table 1. Table 2 shous the species composition for these samples. A scattered
distribution, as expected in a natural environment, is seen. Figure 2 shous
a distribution of the animals by phyla. Figure 3 is a plot of the mean number
of species against sample areas. Also on thegraph are the results of the
first study and summer resampling at Pt. Pinos for comparison. (Note: The
identification of annelids at Pt. 42 and in the resample are more complete than
those at Pt. Pinos. This accounts for an increase of 2-3 species. Houever
the incresse in number of species is also due to finding types not previously
found at Pt. Pinos.
igure h is a plot of mean values of thesimpson index against sample areas,
uhile Figure 5 does the same for the Shannon-einer diversity index. As before,
Pt. Finos results are incorporated for comparison. Note that in all cases the
values at Pt. 42 are higher than those at Pt. Pinos, and that the variations
in these values at Pt. 42 are not as extreme as those at Pt. Pinos.
t. Pinos Table 3 shous the tabulated data for these samples, uhile
able 4 shous the species composition. Note the similarity to the results
of the original survey. Figure 6 shous the distribution by phyla, and Figures
3, 4 and 5 contain the mean values by areas for numbers of species, Simpson
and Shannon-Meiner indices as mentioned above. The results of the summer re¬
samples correspond to those observed earlier at Pt. Pinos, especially in the
area of the outfall. Areas 10 and 12 have louer values for the divesity
indices and number of species than corresponding samples from the Spring.
This differences seemsto be due to seasonal variation at Pt. Pinos.
Table 5 presents the mean values and standard deviations derived from
the tabulated data andused in comparing the three sets of samples. It alst
gives the results of the comparisons betusen the groups using the Student's
t test.
2/6.
21
Discussion
The results shoun in Figures 3, 4 and 5 indicate that algal-microfauna
associations at Pt. 42 are characterized by having more species of animals
and higher diversity indices values than those at Pt. Pinos. If ue accept the
idea of Pt. 12 being a control, a natural environment that is not polluted as
there is reason to believe Pt. Pinos is, then this data suggests that the entirety
of Pt. Pinos is somehou changed. Differences in diversity indices and numbers
of species found in the samples taken around the point shou areas of changed
community structure, uhich correlated with the distribution of seuage effluent
imply that parts of Ft. Pinos are polluted. Accepting the hypothesis that louer
values for species diversity indices and numbers of species uhen correlated
with seuage effluents indicate pollution damage, Figures 3, 4 and 5 imply
that all of Pt. Pinos has suffered pollution damage.
Houever, to test the validity of the data statistical methods were em-
ployed. Significant differences (pe.001) uere found betueen the "polluted'
and "unpolluted" areas at Pt. Pinos and betueen "polluted" areas at Pt. Pinos
and areas at Pt. 12.for the numbers of species of animals found associated with
the algae. There was not a significant difference betueen the "unpolluted"
group and Ft. 42 for this criterion, suggesting that numbers of species of
animals found in a group of samples can reveal changes in a community.
For the diversity indices significant differences (pe.001) were found
betueen all comparisons. This uould suggest that diversity indices vary too
much from sample to sample to serve as effective indicators. Houever, by
comparing the "unpolluted" group with itself and the Et. 42 group uith itself
insignificant differences (p2.2) were found for both diversity indices. This
indicates that the igdices are consistent within a given geographical area
such as Pt. Pinos and that they do serve as indicators of change in a community.
The data thus implies that all oft. Finos is significantly different from
the "control" area and that all of Pt. Pinos may be subtly altered by seuage
pollution, aside from the heavily damaged area in the immediate vicinity of the
outfall. It may be that extreme differences in the numbers of species found, as
at Pt. Pinos, indicate severe changes in a community, uhile the slight dif-
ferences observed at Pt. 42 are the result of natural variation. Diversity
indices on the other hand may reflect more subtle changes that differences in
the numbers of species do not shou.
Besides helping to confirm some of the interpretations of the results of
the first study at Pt. Pinos, namely that certain areas of the point are severely
damaged by seuage pollution, these results allou for the formation of a
hypothesis for testing for pollution damage in an area.
If, by comparing algal microfauna in a presumed polluted area and a
similar unpolluted or less polluted area, an investigator can demonstrate
statistically significant (pe.Ol) differences in the number of species found
or in diversity indices that characterize the community, then he may label
his presumed area as being polluted. Houever, there are several limitations
to such an hypothesis.
The investigator should have some reason for presuming an arsa to be
polluted- visible differences betueen the tuo areas, a polluting element in the
environment or a mechanism to account for the pollution. Also, natural
variations baced on environmental and seasonal differences must not be discounted
As a case in point, consider the approach to the Pt. Finos area. Visible dif.
ferences in the macrofauna and flora in areas near and auay from thebutfall
prompted the investigation of the microfaunal communities. Significant dif
ferences in the numbers of species found and in diversity indices betueen areas
near the outfall and those suay from it uere found. Based on the presence of a
216
seuage outfall and a current system that would distribute the effluent in
pattern corresponding to the damaged areas, the immediate outfall area was
Labelled polluted. Later, in thesummer, another point was sampled and compared
with Pt. Pinos. Also, Pt. Finos was resampled to determine the effects of
seasonal variation on the communities. Results indicated that natural variation
was less than variations observed at Pt. Pinos, andtthat Pt. Pinos algal-
microfaunalassociations uere significantly different than those at a contro
point. Seasonal variation over a tuo month period was found to have little
effect on the Pt. Pinos microfaumal commumities.
Literature Cited
Clearman, David A. 1970. The Effect of Primary Treated Seuage on the
Distribution and Abundance of Microfauna on Endocladia muricata,
Prionitis lanceolata and Corralina vancouveriensus.
Unpublished paper.
1. Location of Prionitis lanceolata sample site.
around Pt. 42, Monterey, California.
leplicate samples are grouped into areas.
sle: 1 inch-approximately 12 meters.
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AREA
Table 1. Tabulated data for samples from Pt.
63
5.8 5152
6.
86
8.7 200
60
6.56
80
7.54 120
7.01 328
2 6.7 214
b. 65 136.
14
10.2 212
9.3 326 10
9.0 238 12
6.783 116
7.4 134
5 2
6.
96
10
12
1.78
1.0
2.9
2.45
2.6
1.7
3.4
2.7
2.9
3. 46
3.5
2.9
2.86
3.6
2.5
—
1.28
2.
2.12
2.0
2.64
2.3
2.6
2.53
2.4
1.9
2.1
1.2

159
6.7
234
2
7.2
84
6.8
5.65 192
7 2 5.3 110 10
86
6.26
186
5.5
2 4.3
66
144
6.7
293
11.0
144
7.6
9 2
8.3
223
12
7.13 216
10 2 7.0 194 10
86
5.8
58
2.1
2.26
2.1
2.8
2.6
2.97
2.8
2.2
1.97
2.3
1.1
1.7
1.64
2.2
0.8
0.6
2.2
2.16
2.2
1.52
able 2.
Species composition for Prionitis lanced
at
samples from Pt. 42. Numbers are numbers of
individuals per 100 grams dry weight of
algae. Species occuring in only one sample
are omitted.
88
81
60
1400
36
222
88
240
112
77
113
54
18
96
112
194
232
212
18
15
22
110
36
60
22
20
24
85
275
66
70
22
12
18
72
224
76
112
14
22
14
28
36
28
11
18
17
14
16
28

80
1870
900
555
330
22
1660
550
480
900
180
550
900
1400
hho
1850
900
1700
180
1080
864
1400
948
1200
2100
600
0

176
22
11
51
17
20
14
9a.
34
11
36
32
22
110
270
400
360
360
270
440
450
420
330
210
270
210
300
180
360
700
286
232
120
360
150
22
2
27
14
68
42
12
18
22
14
18
14
28
36
27
17
18
17
18
2
—
E
12
28
18
18
10
26
12
26
18
18
22
2.
ig.
Distri
samples
ion by ph
la for Prionitis la
42.
2
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ig. 3. Plot of the mean number of species against the
sample areas.
Solid line shous Pt. Pinos, Spring, sample results.
Broken line shous Pt. Pinos, Summer, sample results.
Double line shous Pt. 42 sample results.
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126
12
13
0
2
Fig. 4. Plot of mean Simpson Diversity Index against sample
areas.
Solid line shous Pt. Pinos, Spring, sample results.
Broken line shous Ft. Pinos, summer, sample results,
Double line shous Ft. 12 sample results.
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12
AREA
10
12
10
83
i9. 5. Plot of mean, Stannon-Weiner Diversity Index
against sample areas.
Solid line shous Pt. Pinos, Spring, sample results.
Broken line shous Pt. Pigos, summer, sample results.
Double line shous Pt. 42 sample results.
2
L



L
L

O





12
AREA
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PI. II
2
233
Table 3. Tabulateddata for
onitis lanceolata
from Pt. Pinos (summer)
samples
2
7.8
9.1
50
8.2
7.7
6.9
22
2.6
4.9
2.6 86
3.6
5.3 100
4.8
4.
2
1.6
2.6
2.9
2.1
2.2
1.2
2.4
1.2
0.7
2.0
2.5
2.0
0.(
0.7
2.7
1.0
2.0
0.4
0.0
2.4
0.8
0.4

10 2
12 2
7.67
8.53
7.6
9.3
6.54
9.35
6.68
8.91
202
14
14
268
230
210
250
190
1.5
2.2
1.67
1.7
2.1

1.28
1.45
0.78
1.41
1.56
3
Table 4. Species composition for Pric
mitis lanceolats
samples from Pt. Pinos (summer).
Numbers are numbers of individuals per 100
grams dry weight of algae. Species occuring
in only one sample are omitted.
236
12

5
240
180
120
300
120
360
360
1o0
240
600
440
220
140
120
Lho
360
260
6
18
16
18
24
12
12
33
24
18
27
16
12
12
12
22
12
16
16
12
24
12
16
11
24
8
1500
1100
1330
1550
2400
1660
2400
1656
8a.
12
12
12
18
12
12
12
36
24
11
24
24
12
12
Fig.
Dist
(summer
lancet
amp.
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285
able 5. Mean values and standard deviations for numbers o
species and diversity indices for the three sreas
compared employing Student'st test.
Top: Mean values and standard deviations for
12 and "Polluted" and "Unpolluted" areas
Pt. Finos.
Means values and standard deviations for
Middle:
randomly divided areas of Pt. 12 and
"Unpolluted" areas of Pt. Pinos.
Bottom: Results of comparisons of areas using
Student'st test.
Point Pinos
Polluted Unpolluted
Point +2
(P2)
Areas:
4,5,6,7,8 2,3: 9-13
1-10
No. Species Mean
3.19
8.77
9.03
Std. Dev.
0.75
2.17
1.77
Simpson
Mean
1.36
2.86
2.38
Index
Std. Dev. 0.68
1.13
0.91
Shannon-W
Mean
0.685
1.4g
Index
Std. Dev. 0.29
0.76
0.41
Unpolluted
Point +2
P2
P22
Simpson
Mean
2.69
2.44
3.09
2.31
Std. Dev. 0.26
Index
0.301
2.5
0.305
Shannon-W) Mean
1.80
1.99
1.88
1.71
Index
Std. Dev. 0.11
0.53
0.16
0.16
Results of Student'st Tests
Species
Simpson Index
Shannon-Weiner Index
PxU t-2.53 pc.001
PxU t =10.21 po.001
t-54.37 p.001
PxP2 t -5.21 po.001
PPxP2 t =18.29 p5.001
PxP2 t=243.2
pS.001
UxP2 t - 4.19 p5.001
UxP2 t- 0.1282p2.99
UxP2 t = 22.07 pe.001
XU, t - 0.492 .3ep.l
U,XU2 t - 0.762 .5-p..6
P2 xP2, t - 0.637 .h-p-.5
P21xP2, t - 1.507 .74p-.8