J. Boggs/page 2
ABS
igartina papillata exhibits considerable morpho-
logical and physiological variation over its range of
heights in its characteristic zone in the intertidal
region. Female plants are the more abundant in the lower
and medium regions of the zone, whereas male/steriles
predominate in the highest region. Individuals of
higher regions of the zone are shorter and turflike,
ith relatively thicker thalli at the tips and middle
portions; those of lower regions are longer and more
isolated. The higher plants are better adapted to re-
sist environmental stresses such as desiccation and sa¬
linity variation, as evidenced by slower drying rates
and fewer signs of death relative to plants from medium
and low regions. Male/steriles from high and low regions
are shown spectrophotometrically to differ in pigment
composition, with the darker-appearing low plants con-
taining more chorophyll and biliproteins. Photosyn-
thetic rates of lower male/steriles surpass those of
plants from other regions in parallel with differences
in pigment content. Results on pigment content and pho-
tosynthetic rates of female plants, expecially from lower
regions, are difficult to interpret, possibly because of
unknown physiological effects of the numerous cystocarps.
J. Boggs/page 3
NTRODUCTTO.
Intraspecific physiological variation over a range
of depths and tidal heights has been investigated for
several species of marine algae. When placed in a vari-
ety of osmotic conditions, algae which lived in tide
pools and were accustomed to emersion displayed greater
tolerance than those continuously submerged (Biebl.
1962). Some red algae were reported to have survived
in concentrations ranging from .l to 3 times the con-
centration of sea water. Burns and Mathieson (1972)
determined salinity to be a dominant factor in the dis-
tribution and growth of G.
tina stellata. Biebl (1962)
has also found differences in ability to resist desic-
cation among intertidal and subtidal algae of similar
morphology. The importance of intraspecific morpho¬
logical variation as a basis for differences in resis¬
tance to desiccation has been pointed out by Bergquist
(1959). The photosynthetic efficiency of intertidal
algae when exposed to air was found to depend largely
on their ability to ratain water (Biebl, 1962). The
photopigment content of several intertidal Rhodophyceae
has been qualitatively analyzed by Strain (1951), who
found the pigments in these species to be the same as
J. Boggs/page 4
in deep water species. The relative amounts of these
pigments, however, has not been ascertained.
The variation among individuals of both sexes of
a single species at different heights within the inter-
tidal region is less well documented. Preliminary ob-
ta (C. A¬
servations on the red alga, Gig
rtina papil
gardh) J. Agardh, existing almost exclusively within the
intertidal region and occupying a distinct zone, indi-
cated it would be suitable for such a study. This spe-
cies exhibits remarkable variability in morphological
characters such as length and thickness of fronds over
its height range. It also varies in color from golden
in the higher plants to dark brown in lower individuals.
The distribution and abundance, and physiological vari-
ation of male/sterile and female individuals are not
known.

PHODg
MATERTADS AND PE
For field studies on distribution, abundance and
morphological variation, the following tools were em-
ployed: a 25 meter transect line marked every half me¬
ter; a 15 cm ruler to measure frond length; a micrometer
to measure thickness of fronds to the nearest.l mm.
Thirty transects one meter apart were laid over the
northwest area of Mussel Point, Pacific Grove, Califor-
nia. Each transect line extended from the highest boun-
J. Boggs/page 5
dary of the G.
illata zone (1.1-1.4 m above mean low
low water) to the lowest boundary (0.0-O.3 m above MLLI).
Any G. papillata individual that lay under or fell
across the line was scored for sex, frond length, and
thickness of the frond at the base, middle and tip.
The
individual was also classified according to its rela-
tive height in the G. pap
ta zone, values of 1.0,
0.8, 0.6, 0.4, 0.2, or 0.0 signifying progressively
lower tidal heights. This arbitrary scale should not
be confused with absolute measurements of tidal height.
The crustose tetrasporophyte phase of Giga
ting
papillata,
trocelis sp. (Polanshek and West, 1977) was not inclu-
ded in this study.
In the laboratory, two male/sterile individuals
from low (0.0 - 0.2), medium (0.4 - 0.6) and high (0.8 -
1.0) levels were placed in solutions (200 ml) of vary¬
ing salinity: distilled water, .l times the concentra-
tion of sea water (SW), .5 x SW, SW (control), 3 x SW,
and 5 x SW. Sea water was diluted with distilled water
to obtain lower concentrations, and increased in concen¬
tration by the addition of Instant Ocean crystals. The
plants in their solutions were checked after twelve
hours and then allowed to remain in these concentrations
J. Boggs/page 6
for six days. Any changes in appearance were noted.
particularly color changes indicative of cell death.
Desiccation rates for male/sterile and female
plants from low, medium and high regions were deter-
mined by drying the fronds in the lab at 24°0. and re-
cording weight loss every 30 minutes for eight hours.
To test for variation in pigment content male/
steriles and females from low, medium and high regions
were dried at 25°0., ground in a ball mill, weighed and
their pigments (R-phycoerythrin, R-phycocyanin, and
chlorophyll a) extracted in test tubes. To minimize
denaturation the biliproteins, R-phycoerythrin and R-
phycocyanin, were extracted first in Tris-HOl buffer and
the solutions refrigerated overnight (L.R. Blinks, 1979,
personal communication). The tubes were then centri¬
fuged to sediment suspended particles and the clear so-
lutions placed in a spectrophotometer (Gilford +252)
to determine absorption spectra. Ground samples were
washed with distilled water to remove the buffer, dried.
and the chlorophyll a extracted with acetone (Jensen.
1978). After refrigeration and centrifugation these
solutions were also analyzed on the spectrophotometer.
Photosynthetic rates of low, medium and high plants
J. Boggs/page 7
of each sex were obtained with towel-dried samples in
an infrared gas analyzer (Beckman #215). Light for
photosynthesis was provided by a Quartzlite (Appleton
Electric Co.).
DST
U
The results of field studies are shown in Figs.
1-3. The highest concentration of G. papillata was
found at the medium height level, with females more
abundant than male/steriles (Fig. 1). Male/steriles,
however, were the more abundant in the high region, where
the turflike form predominated. Fig. 2 expresses the
difference in morphology between the short, turflike
high plants and the longer, more isolated low and me-
dium samples. As Fig. 3 shows, tips and middle parts
of plants steadily increased in thickness from low to
high regions. Basal portions became thicker from low
regions up to the lower boundary of the high regions,
where male/steriles began to decrease in thickness. Fe-
males, on the other hand, showed thicker bases in higher
regions.
Although the samples in various salinities all ap-
peared to have survived the twelve hour period, the low
distilled water sample had begun to swell at the tips.
J. Boggs/page 8
This was not observed in medium or high plants for two
more days. Low samples in the higher salinities were
also the first to exhibit pink coloration at the tips.
Higher plants did not turn pink, but became a light
golden or yellow-green. Medium plants displayed a com¬
bination of the characteristics of the other two, the
base turning pink and greening occurring at the tips.
Rates of drying for low, medium and high male/ster-
iles and females are shown in Figs. 4 and 5. To sim¬
plify interpretation, a linear regression was applied
to the linear phases of the curves in Fig. 4, genera-
ting the slopes used to represent initial rates of dry-
ing in Fig. 5. Low male/steriles had a higher initial
drying rate than medium or high male/steriles. Rates
of medium and high male/steriles were similar, but
slightly lower for medium plants. Females, in con¬
trast, dried faster in the higher regions than at me
dium or low levels.
Absorbances at maximum absorbing wavelengths for
the three photopigments are given in Fig. 6. For all
three pigments, male/steriles from high regions showed
lower absorbances than those from medium or low regions.
Medium plants, however, yielded the highest absorbances
J. Boggs/page 9
for females, with the values for low females consider-
ably lower than those of low male/steriles. Except for
chlorophyll a absorbances of medium females, females of
a given height level exhibited lower absorbances than
male/steriles of the same level.
Photosynthetic rates of both sex groups were mark-
edly greater than those of medium and high levels, which
had similar rates (Fig. 7).
r
7
DIS!
USSION
Field studies on the abundance and distribution of
G. papillata revealed that individuals are least abun-
dant in the lower regions of the G. papillata zone (Fig.
1). From the tattered appearance of many of the lower
individuals, it seemed that grazing might play a role
ta. With re-
in limiting the lower range of G. papill
spect to morphology, the short, high plants (Fig. 2),
in contrast to the longer, low individuals, grew closely
together to form a matlike turf. This turf collected
sand and bits of shell and might retard desiccation by
retaining water during low tides. Thicker tips and
middle portions (Fig. 3) might also aid the higher plants
in resisting desiccation. If initial rate of drying is
an indicator of resistance to desiccation, the thicker,
J. Boggs/page 10
resistant plants of higher regions would be expected to
dry slower than the thinner, less often exposed indi-
viduals of lower regions. The results for male/ster-
iles agree with these predictions (Fig. 5). The unex-
pectedly low rate for the lower females might have re¬
sulted from retention of water by the cystocarps and
papillae, which were most numerous on lower females.
The thinner bases of high male/steriles (Fig. 3) can
be explained by their shortness, which might allow them
to be anchored sufficiently by thinner basal portions
than plants of other levels.
Pigment concentrations varied consistently within
the sexes over the range of heights in the G.
pillata
zone. Low male/steriles exhibited the greatest pigment
absorbances and therefore contained more of the three
pigments than medium or high male/steriles (Fig. 6).
This higher pigment content would account for the dar-
ker color of the low male/steriles. The low female
plants consistently yielded values lower than expected
on the basis of their similarity to the male/steriles
in color. Perhaps cystocarps contained less pigment
than ordinary thallus tissue. If they represented a
significant fraction of the total weight of the plant,
they could account for the depressed value of the low
J. Boggs/page 11
females. Most numerous on lower females, cystocarps
were present on all females and might account for the
overall lower values for females than for males of the
same tidal height.
In view of their higher pigment content, the greater
photosynthetic rate of the low male/steriles can be un¬
derstood (Fig. 7). In addition, the similarity in the
rates of the medium and high male/steriles parallelled
their agreement in pigment content. The photosynthetic
rates of female plants, though following the trend of
male/steriles, cannot be explained due to ambiguous
data concerning pigment composition.
rtina papillata displays considerable variation
in morphological and physiological characteristics over
the range of its zone. The higher, turflike individ-
uals must tolerate conditions of extreme physiological
stress in the intertidal region. Lower plants, on the
other hand, less accustomed to harsh physical conditions,
are not as well adapted to meet these conditions. They
seem more exposed, however, to the grazing of intertidal
herbivores. Physiological variation in male/sterile
plants parallelled their expected adaptations, whereas
variation in female individuals was less predictable.
J. Boggs/page 12
A better understanding of the effect of cystocarps on
the physiology of female G. pap
lata is required in
order to meaningfully interpret these data.

ML
TTET
IKNC
I would like to thank William H. Magruder for his
advice, patience and invaluable assistance in the crit-
ical reading of this manuscript, and Dr. Isabella A.
Abbott and Dr. Robin Burnett for their help and sug-
gestions.
J. Boggs/page 13
FERENCE
Bergquist, P. L. (1959) A statistical approach to the
ecology of Ho
sii. Botanica mar.,
1, 22-53.
Biebl, R. (1962) Seaweeds. In: Physiology and Bio-
chemistry of Algae (Ed. by R. A. Lewin).
Academic Press, N. Y., pp. 799-815.
Burns, R. L. and Mathieson, A. C. (1972) Growth and
reproduction of Gigg
ina stellata in New
Hampshire. J. exp. mar. Biol. Ecol., 9,
77-95.
Jensen, A. (1978) Chlorophylls and carotenoids. In:
8
Phycol
andbook of
gical!
ods: Ph
logical and BiochemicalM
thods (Ed. by
J. A. Hellebust and J. S. Craigie). Cam-
bridge University Press, Cambridge, pp. 59-70.
Polanshek, A. and West, J. A. (1977) Culture and hybri-
dization studies on
tina papillata.
Phycol., 13, 141-149.
9.
Strain, H. H. (1951) The pigments of algae. In:
J. Boggs/page 14

cology (Ed. by G. M. Smith). Chron¬
ual ol
ica Botanica Co., Waltham, Mass., pp. 243-262.
N
8
J. Boggs/page 15
INDIVIDUALS
OF
NO.

8

kkkkk -








—




—

—
P-






—
9.0
3.0
7.0
6.0
5.0
4.0
3.O
O.O
J. Boggs/page 16
(males in black)
L1

O.6
O.4
0.8
0.2
HEIGHT IN G. PAP. ZONE

1.0
30
20
10
60
55
50
40
35
.85
75
65
55
45
(males in black)
—
O.O
L 1
O.2


O.4

J. Boggs/page 17

O.8
O.6



1.0
n
O


C
O

O
% WEIGHT
—






. .

5


LOSS
J. Boggs/page 18
C
—
DRVING
J. Boggs/page 19
RA T E S (slopes of linear phases)
8
O

I 31
O
2
0

ABSORBANCE
3
8
8 0

—


.




















—
a

ens
3

J. Boggs/page 20

—
0
1.40
1.30
Elso 1. 20
S.
1.10
1.00
90
80
70
60
50
40 —
J. Boggs/page 21
(males in black)

1

H1
10
MED
HEIGRT IN G. PAP. ZONE
—
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
J. Boggs/page 22
FIGURDS

Number of G.

pillata individuals

counted as a function of height in the G.
papillata zone. 0.0 represents lower boun¬
dary of zone, 1.0 the higher boundary. Male/
steriles in black, females in white.
i
ata in-
Mean frond length (cm) of G. pa

dividuals as a function of height in the G.
illata zone. 0.0 represents lower boun-
dary of zone, 1.0 the higher boundary. Male/
steriles in black, females in white.
Mean frond thickness (mm) measured at the
tip, middle and base of G. papillata indi-
viduals for the six height divisions in the
G. papillata zone. 0.0 represents the lower
boundary of the zone, 1.0 the higher boundary.
Male/steriles in black, females in white.
rying rates for male/steriles and females
from low, medium and high regions of the G.
papillata zone, shown as percent weight loss
over time.
rying rates (plotted as slopes of the lin-
ear phases of curves in Figure 4) for male/
Figure 6.
Figure 7.
J. Boggs/page 23
steriles and females from low, medium and
high regions of the G. pap
illata zone.
Grouped male/steriles of different heights
at left, females at right. L (black) sig-
nifies low height in zone, M (cross-hatched)--
medium, H (white)--high. The variance be-
tween these slopes is significant at the
99% confidence level: p «.001.
Absorbances of R-phycoerythrin, R-phycocyanin,
and chlorophyll a at maximum absorbing wave-
lengths (565 nm, 615 nm and 430 nm, respec¬
tively) for male/steriles and females of low,
medium and high heights in the G. pap
illata
zone. Male/steriles in black, females in
white.
Photosynthetic rates (mg 00, consumed per
g dry weight algae per hour) for male/ster-
iles and females from low, medium and high
regions of the G. papillata zone. Male/
steriles in black, females in white.