ABSTRACT
BACHELOR, E. P. (Hopkins Marine Station of Stanford
University, Pacific Grove, California), A Comparative
Study of the Productivity of Prionitis lanceolata
Harvey Near and Away from the Carmel Marine Sewage
Outfall.
The benthic red alga Prionitis lanceolata
Harvey shows an increased primary productivity in
the outfall canyon of the Carmel, California, marine
sewage outfall. At a distance of twenty meters from
the outfall this productivity shows a large reduction
before again rising to a high value at approximately
20 to 40 meters. The differing productivities of
samples from Mission Point, Monastery Beach, and
Cabrillo Point (Hopkins Marine Station) are compared
in relation to the currents which were found. Possible
causes for these differences in productivity are
discussed. The validity of the "light and dark bottle
method of benthic algal productivity measurement
used here is also discussed.
INTRODUCTION
Prionitis lanceolata Harvey is a species of
benthic red algae which is widely distributed in
the Monterey Bay, California, intertidal regions,
generally occurring in the +1.0 to -1.5 foot tide
levels. This alga has been found in very close
proximity to the marine sewage outfalls of Carmel
and Pacific Grove, and for this reason was chosen
as an experimental tool of marine sewage pollution
study. The increasing problems of waste disposal
in the bay area have made change mandatory; the
need for a good indicator of sewage pollution has
become increasingly necessary, so that intelligent,
ecologically acceptable decisions may be made
concerning the future of the marine sewage outfalls.
This paper presents the results of primary
productivity measurements of P. lanceolata samples
collected near and away from the outfall. Some
hypotheses are made with respect totthe sewage's
effect on the primary productivity. The "light and
dark bottle" method of algal productivity measurement
as used here, was found to not be especially applicable
when applied to benthic marine algae. Therefore,
the significance of the results should be accepted cautiously.
MATERTALS AND METHODS
Knowledge of the dispersion behavior of the
sewage was important to both the collection of
samples and the interpretation of experimental results;
therefore, two group projects were completed during
the term of study. First, a map of the immediate
outfall area was constructed through the use of
compass readings and measured lines. This map was
marked in a grid with squares proportional to 625 ft
of area. Each of these squares was in turn divided
into 25 squares, each with sides proportional to
five feet. This gridded map (figure 1) greatly
aided in location and identification of algal samples.
A map of the entire Carmel Bay area, partially
represented in figures 3, 4, was obtained from the
California State Department of Beaches and Parks.
Second, two current studies were undertaken
using fluorescein dye and color coded, marked bottles.
The bottles were set from a small skiff in predetermined
lines, and compass readings (figure 2, tables I, II)
made at timed intervals from a suitable reference
point. The bottles' actions were then plotted using
this information (figures 3, 4). The dye was made
up into 40 gm packets, containing a 3"x 3" x ½
piece of plywood as a floating device, and used to
mark the bottle drops from the skiff and to conduct
microcurrent studies in the immediate area of the
outfall (figure 5).
Collection of sample:
Prionitis lanceolata was collected, labeled
with the collection site sample number (e.g., 50-b),
and placed in plastic bags for transport to the lab.
The location, time of collection, tidal conditions,
and a description of the algae and the collection
site were all noted on a collection sheet (appendix).
If the alga was to be used at a later time it was
stored in Dr. L. R. Blinks' greenhouse aquaria.
Experimental procedure
Before testing, algal samples were scrubbed
with fresh sea water to remove as many of the
epiphytes and epizoites as possible. Algal
sections of approximately the same size, and from
the same part of the plant, were cut and placed into
the clear and opaque B.O.D. bottles. After the
volumes of the bottles were measured, the bottles
were filled with sea water which had had No gas bubbled
through it for approximately ten to fifteen minutes.
A pump system was devised which allowed this water
to be transfered to the bottles from the carboy using
the Nitrogen as the pumping source. Thus, only a
minimal uptake of atmospheric oxygen by the water was
allowed. The aeration by Nitrogen lowered and standardized
the ambient dissolved oxygen in the sea water appreciably.
The B.O.D. bottles were then sealed, their stoppers
taped in place, and incubated for one hour in the
holding tanks (depth - +1.5 ft, temperature - 11°c).
At the end of the incubation the bottles were removed,
the dissolved 0, "fixed" (Strickland and Parsons,
1965), and a 50 ml volume removed from each bottle
for the standard Winkler titration (Strickland and
Parsons, 1965). Two "initial bottles" containing
only the aerated sea water were fixed using the same
procedure and also titrated. Test time, duration
of test, ambient conditions (e.g., sunny), and the
titration results were noted on a test data sheet
(appendix). The algae were removed from the bottles,
placed on filter paper, and dried in an oven. After
being allowed to cool in contact with the air, the
algal samples were weighed individually. Calculations
of the gross productivity, net productivity, and
respiration were made using modified formulas from
Strickland and Parsons (1965).
6
RESULTS
The gross productivity and net productivity of
Prionitis lanceolata showed changes with increasing
distance from the outfall (figures 6, 7). These changes
coincide fairly well with one another, the net
productivity showing less erratic behavior, and thus
possibly being a better measure of the true productivity.
The results were also plotted as a function of the
visual dispersion of the effluent (dye studies).
This curve shows the same trend as the others, but
is probably the best interpretation of the data,
since it most closely illustrates the actual effects
of the effluent at the outfall. The results indicate
an increased productivity rate at the outfall,
followed by a decline in this rate a short distance
away. The productivity is again elevated 20-40 meters
from the outfall, decreasing to a low at approximately
70 meters. Beyond this distance, values to the south
of the outfall are greater than those found for the
algae which lie to the north of the outfall and for
the HMS control. This trend correlates with the
currents found in the bay (figures 3, 4).
-6-
DISCUSSION
The pigment content per gram wet weight of
Prionitis lanceolata has been shown to be at high
levels in samples from very near sewage outfalls,
and to decrease to a much lower value a short distance
away (10-20 meters). This pigmentation rises to
a normal value at a greater distance from the outfall
(40-120 meters) (Peter Roy, personal communication).
The increased pigmentation of the algae found in
closest proximity to the outfall may not, however
cause the increase in productivity seen experimentally
(figures 6, 7) when the algae remain in the outfall
environment. The alga in its natural environment
may be affected by increased growth of epiphytic
diatomaceous slime, turbidity, and other factors
introduced by the effluent such as changes in temperature,
salinity, and pH. The extra pigmentation in the
outfall canyon samples may be an adaptation which
suffices only to raise the production to a level
close to that of other "unpolluted" members of the
same species. Conversely, the increased pigmentation
may actually cause an elevated productivity at the
outfall.
A profitable continuation of this experiment
-7-
would be firstly, to test unwashed algae from the
outfall canyon in its environmental water, rather
than introducing this alga, scrubbed, into fresh
sea water. This would give a truer indication of
the productivity of the alga under those environmental
conditions present. Secondly, to test for productivity
changes versus the pigment content of the alga, which
should seemingly have a large effect on the productivity.
Increased amounts of nutrients introduced into
the area via the outfall may account for the increases
in productivity found at greater distances (20-120
meter radius), where pigmentation might be at a normal
level. Currents in the bay move predominantly to
the south from the outfall (figure 3), thus, increase
in nutrients with some dilution may also account
for the greater productivity found at Monastery Beach
compared to those found for the algae at Mission
Point to the north and the HMS control.
The validity of the experimental procedure used
here for the benthic marine algae may be doubtful.
During incubation air bubbles tended to accumulate
on the surface of many of the algal samples. These
bubbles did not dissolve into solution. These bubbles
may have been 0, produced by the algal sample, and
an error is present in the results found since true
production was not measured. This error is probably
about 3%. If the bubbles were produced by an epiphytic
-8-
slime, their presence would not invalidate the results.
However, where slime covers the algae there may be
a decreased productivity due to reduction of incident
light (L. R. Blinks, personal communication).
Other experimental parameters may cause erroneous
results. Incident sunlight was used as the light
source for incubation. Tests run at different times
of day would necessarily produce inconsistencies
in this parameter. "The effect of production of a
given quantity of algae varies from hour to hour.
It may be reduced both by increase and decrease of
the light intensity to which the species are adapted.
Therefore, the assimilation rate oscillates according
to time of day as well as to weather" (Findenegg, 1964).
The portion of the algae used for the testing also
may produce large variation in the results, even if
care is taken to select opposing branches of like
size from the same portion of the plant (James
Schreiber, personal communication).
There are many factors which affect the light
and dark bottle method of algal productivity measurements.
The data suggests that there are definite effects
occurring on the productivity of P. lanceolata at
the outfall; a larger sample size would introduce
more certainty into the results. The results presented
in this paper and their significance should be accepted
with caution, until more evidence is presented.
78
ACKNOWLEDGEMENTS
I would like to extend my thanks to all of the
professors at Hopkins Marine Station who made themselves
available for consultation and assistance at any time
and were instrumental in the completion of my research.
A special thank you is given to Dr. Isabella Abbott
for her kind encouragement and help. Jim Schreiber
Van Remson, Mike Nakata, Doug Grey, Joe Welsh, and
Jim Sutton—-Thank you.
Supported in part by the NSF Undergraduate
Research Program Grant No GY-7288.
10-
REFERENCES
Findenegg, I. 1965. Relationship Between Standing
Crop and Primary Productivity, p. 273. In C. R.
Goldman (ed.), Primary Productivity in Aquatic
Environments. Mem. Ist. Ital. Idrobiol., 18
Suppl., University of California Press, Berkeley.
Strickland, J. D. H., and T. R. Parsons. 1968.
i Practical Handbook of Seawater Analysis.
Fisheries Research Board of Canada, Ottawa, 311 p.
Figure 1. The immediate outfall area showing collection
sites (A) and the sample numbers. Scale 1:120
Figure 2. All readings in tables I and II are in
degrees east of North. Recovered
bottles are designated :.
The initial positions and end points of the
Figure 3.
bottles in current study 1 are designated
Recovery points are indicated by Q.
Scale 1:10,000
Initial and end positions of the marked
Figure 4.
bottles are indicated by  in current
study 2. Recovered bottles are marked 2
Scale 1:10,000
Currents in the area immediate to the
Figure 5.
outfall are indicated by the heavy black
arrows. Note the trend for the currents to
move across the outfall to the south and
generally miss the southern end of the
rocky area. Scale 1:120
The gross productivity of P. lanceolata as a
Figure 6.
function of the distance from the outfall is
diagramed by the heavy dark line. Net productivity
is indicated by the thinner line. H, Hopkins
Marine Station; MB, Monastery Beach; MP, Mission
Point.
Figure 7.
Figure 8.
Table III.
(appendix)
Net productivity is plotted as a function
of distance from the outfall for Prioniti:
lanceolata. H, Hopkins Marine Station;
MB, Monastery Beach; MP, Mission Point.
Gross productivity of Prionitis lanceolata
is plotted versus the effluent distribution
as estimated from the dye studies.
inc. t., incoming tide; otg. t., outgoing tide;
s, sunny; br, bright; oc, overcast; g, gross
productivity; n, net productivity; r,
respiration
x


o
8


0
outtatt
2


a. 3



2


3
2
0
Figure 3
Monastery
Beach
2
20
outfall
area
Carmel
River
ke
Point Lobos
M
Carmel Bay
2n
9
10


Current Studyl
5-11-10
Mission
0930-1630
Point

bottle
dye
Figure!
Monastery
Beach
As ,
124

outfall
area
Carmel
River

..
S
Point Lobos
M
H n p


Carmel Bay-
10
Current Study 2
5-25-10
1000-1400
Mission
Point



80
S

8
8
952
21







+

48
5

8
8
8
productivity in mgC/mgdry weight alga/hr.
82
55
9

L



L




2
LE
a
L





LE
2
2 G
2
e



8
8
8
—
EE

saaaa-

net productivity in mg.C/mg.dry weight alga/hr.

1
0
9i




a


-
—

a
e


5
15

5



18
S
8
A
8
A

2
productivity in mg.C/mg. dryweight algafhr.
44
8o
95.
X
sample
number
22-h
64-h
30-g
54-h
44-p
47-9
48-n
27-s
28-h
50-b
H-1
O2 PRODUCTIVITY TESTRESULT
conditions
sample
mgCmgdrywth
mgcing dynth
date
number
9.1837
0.11372
oc,br
0.0111
H-5
0.00552
inc.
5-8
0.00116
0.000005
0.18506
br
O.11199
0.02393
0.00902
H-6
otg.
-0.0015
5-12
0.00000
0.31656
0.207587
br
0.015
MP-1
0.01174
otg.
5-12
0.00091
0.00018
0.10807
0.261847
br
0.00807
0.01089
MP-2
otg.
5-
0.00066
-0.00069
8
0.19255
0.13887
br
0.00382
0.00618
otg.
MP-3
5-
0.00083
0.00413
0.1387
O.11466
br
0.00279
0.00667
22-1
otg.
5-
0.00015
-0.00046
0.15105
0.11947
s,br
0.00599
0.06365
otg
17-s
5-
-0.00019
0.00033
0.21388
br
O.07951
n
0.00082
otg.
MB-1
O.01545
5-14
-0.00026
0.0000
0.027
s,br
0.0hl80
0.00084
0.00999
otg.
MB-2
5-11
0.00002
0.00179
0.50665
0.011306
s,br
0.000187
MB-3
0.03916
otg.
5-14
0.00003
0.00118
0.11086
s,br
0.16400
0.00234
0.01915
otg.
MB-4
0.00008
5-15
-0.00198
O.114098
0.21790
s.br
8
conditions
date
br
inc.
br
inc.
5-
br
otg.
-19
br
otg.
5-
s,br
otg.
5-19
br
inc.
5-2.
br
inc.
5-22
br
inc.
5-22
br
otg.
5-23
br
otg.
5-23
br
otg.
5-2:
s.br
P.
sample
number
22-h
64-h
30-8
51-h
Ml-p
47-9
18-n
27-s
28-h
50-b
H-1
H-2
H-3
H-l
22-u
51-s
12-m
O2-PRODUCTIVITY TESTRESULTS
ang eng an uthn conditions
mg Cngdryut husconditions
sample
date
number
date
oc,br
0.11372
s,br
0.18373
H-5
inc.t
inc.t
0.01113
0.00552
5-8
5-19.
0.00116
0.000005
O.1199
0.18506
s,br
s,br
0.00902
inc.t
0.02393
otg.t
H-6
-0.00154
5-12
0.00000
5-19
— s,br
O.207587
0.31656
s,br
otg. t
otg.t
0.01511
MP-1
0.01174
-0.00091
5-12
O.00018
5-19
0.261847s,br
0.10807
s,br
0.00807
0.01089
otg.t
otg.t
MP-2
0.00066
5-19
-0.00069
5-12
0.13887
—s,br
0.1925
s,br
0.00618
0.00382
otg.t
otg. t
MP-3
5-19
0.00083
5-13
0.00413
0.14466
s,br
0.1387
s,br
0.00279
otg. t
0.00667
inc.t
22-p
5-13
5-22
0.00015
-0.00046
0.15105
s,br
s,br
0.11947
otg. t
inc.t
0.06365
0.0059
47-s
5-22
5-13
-0.00019
0.0003
0.21388
0.07957
s,br
s,br
0.00082
otg. t
inc.t
MB-1
O.01515
-0.00026
5-22
0.00004
5-14
0.02781
O.Oh180
s,br
s,br
0.00084
0.00999
otg.t
otg.t
MB-2
5-14
0.00002
0.00179
5-23
0.011306
s,br
0.50665
s,br
0.000187
otg. t
otg.t
MB-3
0.03916
0.00003
5-23
5-14
0.00118
0.11086
s,br
0.16400
s,br
0.0023
otg.t
MB-1
0.01915
otg.t
0.00008
-0.00198
5-23
5-15
0.21790
0.114098
s,br
s,br
0.00637
otg.t
MP-L
0.01163
otg.t
0.00005
5-15
5-23
-0.00059
s,br
0.11595
s,br
0.07033
0.00865
otg. t
MP-5
0.00846
otg. t
5-15
0.00008
-0,00215
5-23
0.18079
O.109866
s,br
s,br
inc.t
0.01246
MP-6
O.01915
otg. t
5-19
-0.00109
5-23
0,0000l
0,22778
0.0877121
oc br
oc, br
0.00560
otg.it
0.00912
otg. t
5-26
0.00126
0.00105
5-26
0.12581
0.13704
oc,br
oc, br
0.013269
G-2 0.01190
otg.t
otg.t
0,00372
5-26
0.0003.
5-261
oc,br
0.0557
—0.03706
oc, br
0.01026
otg.t
17-u
0.01036
otg.t
-0.00018
5-26
5-26
0.00151
95