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Winter 1975
AN ECOLOGICAL STUDY OF FUCUS SPIRALIS LINNAEUS
RICHARD ALBERT NIEMECK
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NIEMECK, Richard Albert, 1940- AN ECOLOGICAL STUDY OF FUCUS SPIRALIS LINNAEUS.
University of New Hampshire, Ph.D., 1975 Botany
Xerox University Microfilms, Ann Arbor, Michigan 48106
THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED. AN ECOLOGICAL STUDY
OF
FUCUS SPIRALIS LINNAEUS.
by
RICHARD A. NIEMECK
B.S., Valparaiso University, 1963
M.A., Valparaiso University, 1965
A THESIS
Submitted to the University of New Hampsh
In Partial Fulfillment of
The Requirements for the Degree of
Doctor of Philosophy
Graduate School
Department of Botany
December, 1975 This thesis has been examined and approved.
(£, C r .______
Thesis director, Arthur C. Mathieson, Prof. of Botany
, ^ . ■ w — ....- — - ■■ •
Alan L. Baker, Asst. Prof. of Botany
o-' - ■ ■ /\6 ■ -- ■ " - '■ nr— 1 ■ • ■ “ ■ . ... . - ---- — ■.
Robert Blanchard, Asst. Prof. of Botany
A. Linn Bogle, Asso. Prof. of Botany
Robert A. Croker, Asso. Prof. of Zoology
Date ACKNOWLEDGEMENTS
Dr. Arthur C. Mathieson receives my deepest apprecia tion and gratitude for his timely assistance, guidance and moral support throughout this study and for his careful review of the manuscript. I would also like to thank the members of my committee for their time and efforts in assist ing me in my study and also for their review and constructive criticism of the manuscript: Dr. Alan L. Baker, Dr. Robert
Blanchard, Dr. A. Lynn Bogle, and Dr. Robert A. Croker.
The following people also receive my appreciation:
Dr. Jan Chock for his assistance in the collection of field data and photography; Raymond Connelly for the photographic work; Timothy Norall for providing some of the nutrient in formation; Wendy Elcome and Chris Emerich for assistance with the graphs and drawings; and Mrs. Linda Wright for her moral support and typing the manuscript.
I offer my deepest appreciation and thanks to my wife, Susan, for her encouragement throughout this work, without whom it would not have been completed. TABLE OF CONTENTS
LIST OF FIGURES...... v
LIST OF T A B L E S ...... viii
ABSTRACT ...... ix
INTRODUCTION ...... 1
MATERIAL AND METHODS ...... 3
DESCRIPTION OF STUDY AREAS AND ENVIRONMENTAL CONDI TIONS...... 9
REPRODUCTION AND GROWTH OF FUCUS SPIRALIS...... 12
VERTICAL DISTRIBUTION AND BIOMASS OF F. SPIRALIS AND ASSOCIATED FUCOIDS ...... 15
HORIZONTAL DISTRIBUTION OF FUCUS SPIRALIS...... 17
WATER LOSS OF FUCUS SPIRALIS AND ASSOCIATED FUCOIDS. . 18
MANOMETRIC STUDIES ...... 19
Light...... 19
Temperature...... 19
S a l i n i t y ...... 21
Salinity and Temperature ...... 21
DISCUSSION ...... 23
SUMMARY...... 37
REFERENCES ...... 39
APPENDIX
Station Descriptions...... 45
iv LIST OF FIGURES
Figure 1 Morphology and Reproductive Develop ment of Fucus spiralis...... 53
Figure 2 Map of the New Hampshire Seacoast and Study Sites ...... 55
Figure 3 Variations in Surface Water Temperatures and Salinities at Jaffrey Point, New Hampshire, July 1972 to September, 1973 . 57
Figure 4 Seasonal Reproductive Phenology of Fucus spiralis plants at Jaffrey Point, New Hampshire, during 1972...... 59
Figure 5 Stature and Reproductive Frequency of Fucus spiralis Plants at Jaffrey Point, New Hampshire, July to September, 1972. . 61
Figure 6 Average Monthly Growth of Tagged in situ Fucus spiralis Plants at Jaffrey Point, New Hampshire, July 1972 to August 1973 ...... 63
Figure 7 Seasonal Survival of Tagged _in situ Plants of Fucus spiralis at Jaffrey Point, New Hampshire, July 1972 to July 1973 ...... 65
Figure 8 Size-Frequency Distribution of Lost Tagged Plants of Fucus spiralis at Jaffrey Point, New Hampshire...... 67
Figure 9 Seasonal Growth of Fucus spiralis Plants at Jaffrey Point Between July 1972 and 1973...... 69
Figure 10 Vertical Distribution and Biomass Variations of Fucoid Algae at Jaffrey Point, July 1 9 7 3 ...... 71
Figure 11 Vertical Stratification of Average Weights, Lengths and Reproduction Status of Fucus spiralis Populations from Jaffrey Point, New Hampshire, June 1974 . 73
v 12 Size Frequency Distribution of Fucus spiralis Plants at Different Eleva tions at Jaffrey Point, June 1974...... 75
13 Vertical Distribution and Biomass Variations of the Fucoid Algae at Fort Constitution, July 1973 ...... 77
14 Horizontal and Vertical Distribution of Fucus spiralis Within the Great Bay Estuary S y s t e m ...... 79
15 The Cumulative Water Loss of _in situ Plants of Fucus spiralis, F. vesicu- losus, F_. vesiculosus var. spira lis and A. nodosum ...... 81
16 The Cumulative Water Loss of _in situ Plants of Fucus spiralis from Different Elevations ...... 83
17 Net photosynthesis of Fucus spiralis, F. vesiculosus and F. vesiculosus var. spiralis at Various Light Intensities and 15 C ...... 85
18 Net Photosynthesis of Winter and Summer Plants of Fucus spiralis at Various Temperatures, 1000 foot-candles...... 87
19 Net Photosynthesis of Winter and Summer Plants of Fucus vesiculosus at Various Temperatures, 1000 foot-candles...... 89
20 Net Photosynthesis of Winter and Summer Plants of Fucus ves iculosus var. spiralis at Various Temperatures, 1000 foot-canldes 91
21 Net Photosynthesis of Fucus spiralis and Fucus ves iculosus in Various Salini ties and 15 C...... 93
22 Net Photosynthesis of Fucus ves iculosus var. spiralis in Various Salinities and 15 C ...... 95
vi Figure 23 Net Photosynthesis of Fucus spiralis in Various Salinities, 5 and 25 C. . . . 97
vii LIST OF TABLES
Table I Hydrographic Data for Study Sites During 1973-1974...... 47
Table II ASW Salinity Chart...... 48
Table III Annual Growth of Twelve Tagged Plants of Fucus spiralis, June 1972-June 1973. . 49
Table IV Growth of Forty Tagged Plants of Fucus spiralis, July 1972-Noveraber 1972 .... 50
vii i ABSTRACT
An autecologica1 study of Fucus spiralis was conduct
ed at Jaffrey Point, New Castle, New Hampshire and the ad
jacent Great Bay Estuary System from 1972-1975. The distri
bution, growth, reproductive periodicity, attrition and long
evity of the plants are described in relation to a variety of
environmental factors. Fucus spiralis exhibits a broad,
discontinuous estuarine distribution within the Great Bay
Estuary System. The presence or absence of substratum is
considered to be a factor determining its discontinuous distribution, as it is usually associated with metasedimen-
tary or metavolcanic rock outcrops. The maximum growth and
reproduction of F_. spiralis occur during the summer, with a maximum in August. A growth rate of 1.9 to 2.8 cm/month was recorded during the summer period, while the average monthly growth rate throughout the year was 1.1 cm/month. Two major attritions of Fh spiralis populations occur during the winter and summer. The average longevity of F. spiralis plants is approximately two years. The F. spiralis zone occurs in the uppermost intertidal area between +2.12 and +2.39 meters, above mean low water. A microstratification of biomass,
stature and reproduction of F. spiralis plants occurs within this zone. Average plant weight, length and fertility tend to decrease with increasing elevation. Fucus spiralis loses
ix water at approximately one-half the rate of the associated fucoid algae Fucus vesiculosus, F. vesiculosus var. spiralis and Ascophyllum nodosum. Manometric studies show that F. spiralis has a broad tolerance to light, temperature and salinity, in agreement with its natural distribution in coastal and estuarine locales.
x INTRODUCTION
The marine brown alga Fucus spiralis L. (Fucaceae;
Fucales) is one of seven Fucus species recorded (Taylor,
1957) from the northeastern coast of North America (Fig.l).
It extends from New York to the Lower Saint Lawrence, and
Newfoundland to the North Atlantic shore of Europe and the northeast Pacific (Norris and Conway, 1974). Fucus spiralis is a common species of the high intertidal area where it is exposed to extreme variations of atmospheric conditions.
Relatively little is known about the autecology of
New England seaweeds (Webber, 1975) , particularly F_. spiralis. in contrast, many European workers have conducted extensive autecological studies on other Fucus species such as Fh ves iculosus and F. serratus in the British Isles (Knight and Parke, 1950; Burrows and Lodge, 1951) and F. versoides in the Adriatic Sea (Linardic, 1940, 1949). As far as I am aware, only one account has been published on the autecology of F. spiralis (Subrahmanyan, 1961) , and no autecological investigations have been conducted on the species in North
America. Subrahmanyan (1961) studied the growth, reproduc tion and longevity of F_. spiralis on the Isle of Man. Other than his account, only general descriptions of Eb spiralis populations are given (Lewis, 1972), as well as occasional references to its physiology and desiccation tolerances
1 2
(Stocker and Holdheide, 1938; Baker, 1910; Zaneveld, 1937;
Kristensen, 1968; and Kremer and Schmitz, 1973).
The study was undertaken to elucidate the autecology of F_. spiralis in New England. The specific objectives of the study were to: (1 ) establish the plant's seasonal pattern of growth and reproduction; (2 ) determine the major environ mental factors influencing its growth and local distribution;
(3) understand the population dynamics of the species and;
(4) contrast the autecologies of Fucus spiralis with F. vesiculosus and its variety spiralis. In order to accomplish these objectives, a series of field and laboratory investi gations were conducted from 1971-1975. 3
MATERIALS AND METHODS
Monthly values of surface water temperature and salinity were recorded during high tide at Jaffrey Point,
New Hampshire, U.S.A. (Fig. 2 and Table I) from July, 1972 to September, 1973. A laboratory grade mercury thermometer and a set of hydrometers (G.M. Manufacturing Co., New York) were used for the determination of temperature and salinity, respectively. Salinity values were corrected to 15 C.
Random samples of 50 F. spiralis plants were collec ted monthly during the period of the study at Jaffrey Point,
New Hampshire, to evaluate the plant's growth and reproduc tion. Random collections were employed, rather than quad rats, because of the narrowness of the plant's zone and the sparseness of the population during the winter. After collection, the plants were transported to the laboratory in plastic bags and examined within 24 hours. The percent age of fertile receptacles/plant, as well as the damp dried weight and maximum length of each plant were recorded.
The following criteria were employed to designate a fertile receptacle (Fig. 1) after sectioning many conceptacles and observing their reproductive development: (1) the tips were two cm or more in length, (2) the tips were swollen and filled with mucilage, (3) exodites or mucilaginous substances were extruded from the conceptacles in large 4 quantities,
The growth rate (average elongation/month) of tagged in situ plants of F_. spiralis was also determined at Jaffrey
Point. One hundred plants were tagged during July, 1972, by placing plastic tags around their stipes, and their max imum lengths were recorded monthly until October, 1973.
Since a large loss of tagged plants occurred, 25 additional plants were tagged on December 18, 1972, and another 20 on
April 21, 1973. An attrition rate was calculated from the monthly losses of plants. A statistical analysis of growth rates versus the initial size of the tagged plants was evalu ated after the correlation coefficient analysis described by Bishop (1966).
The zonation and biomass distribution of F. spiralis and associated fucoids at Jaffrey Point, New Hampshire, were determined during July, 1973. A metered transect line was 2 pulled through the fucoid belts and a 0.25 m area was denuded at 0.5 m intervals from the top to the bottom of the belt. The elevation of each quadrat was recorded by a stadia rod and transit, using mean low water mark (MLW) as a reference point (Anon. 1972) . All of the plants within the quadrats were harvested with a putty knife. Subse quently the different fucoid species were sorted and then dried for 48 hours at 100 C. The micro-stratification of 5
F_. spiralis within its belt at Jaffrey Point was also studied.
Thus, the size, weight, biomass (g dry weight/.03m ) and frequency of reproduction of JT. spiralis were determined during June, 1974.
A general survey of the horizontal and vertical distribution of F. spiralis was conducted from the open coast at Jaffrey Point to Ft. Constitution (Fig. 2), be cause of the apparent transition from F. spiralis to F. vesiculosus var. spiralis between the two sites. Line transect-quadrat studies were conducted at Fort Constitu tion in order to evaluate the relative abundance of the intertidal fucoids at this site. A survey of the estuarine distribution of F. spiralis was also undertaken within the
Great Bay Estuarine System to correlate the species distribu tion with one or more environmental factors. Observations and collections of F.. spiralis were made at six sites from
Jaffrey Point to the headwaters of Great Bay (Fig. 2): (1)
Jaffrey Point; (2) a Piscataqua River site opposite the
Schiller Power Plant; (3) Dover Point; (4) Fox Point; (5)
Adams Point; and (6 ) Nannie island. Samples of Fucus plants were collected and habitat notes were recorded.
A complete set of herbarium voucher specimens documenting the presence of F_. spiralis plants at the six study sites is deposited in the algal herbarium of the University of New 6
Hampshire (NHA).
Two comparative studies of the jLn situ rates of water loss in F. spiralis, F. vesiculosus, F. ves iculosus var. spiralis and A. nodosum were conducted. Fucus vesiculosus and F. spiralis were evaluated at Jaffrey Point. Two speci mens of IT. spiralis were studied from the top, middle, and bottom of its zone (+2.12 to +2.36 m) while four plants of
F. ves iculosus were studied, two from the top and two from the bottom of the F_. ves iculosus-A. nodosum zone. The speci mens of each species were approximately the same size and length. Each of the plants was individually tagged and retained at its original location on the shore. The plants were weighed every 30 minutes from the time of their emersion until they were submerged again. The water loss for each plant was expressed as a percentage of the initial water content. A second desiccation study was conducted on Aug ust 23, 1973, at Fort Constitution with four plants each of
F. vesiculosus var. spiralis and A. nodosum. Two plants of each species were from the top, and two others were from the bottom of their respective zones.
Comparative manometric studies were conducted on
F. sprialis, F. vesiculosus and F. vesiculosus var. spiralis, with the net or apparent photosynthesis being evaluated under a variety of different temperature, light and salinity 7 conditions. Fucus spiralis and F. vesiculosus were collected at Jaffrey Point, while F. ves iculosus var. spiralis was collected at Adams Point. The plants were transported to the laboratory within an hour. Vegetative tips, approximate ly 1-2 cm long, were employed for all experiments, and were selected randomly from different plants. The tips were immersed in 100 ml of artificial sea water (Chapman, 1962), and then incubated in the dark for 24 to 48 hours. The incubation period was employed to avoid wound respiration and to acclimatize the plants to different temperature and salinity regimes. The rates of apparent or net photosynthesis were measured with a Gilson Differential Respirometer (Model
GPR 14), equipped with fourteen 50-watt (Champion) reflector lamps. The intensity of the light reaching the bottom of the flasks was varied with a rheostat. A single tip was used per flask in all of the photosynthetic experiments to avoid shading. Five ml of buffered, artificial sea water (Chapman,
1962) was used in each flask. The tips were equilibrated for
30 minutes in the dark and then another 15 minutes in the light, prior to the beginning of each net photosynthetic run. Each run was 30-60 minutes in length with readings taken at 10-minute intervals. The values for oxygen exchange are expressed as ul 0 2 /g dry weight/0.5 minutes. Five replicates were used in the light experiments, while 7 and 8
14 replicates were used in the salinity and temperature
experiments, respectively. The number of replicates employed
was determined after multiple experiments in which the range
of variations was evaluated; the constraints of prolonged
time also dictated the number of replicates. The manometric
techniques employed were after Mathieson and Burns (1971).
In the salinity experiments, concentrations were made by diluting concentrated (2x) artificial sea water with
distilled water, according to the summary in Table II. A
uniform buffer solution of NaHCC>3 and Na2 CC>3 (Chapman, 1962) was added after the appropriate dilutions of salt. Thus,
the concentration of carbonate buffers in the sea water was the same for all salinities. The pH ranged from 8.1-
8.2. Salinity tolerances of F. spiralis and F. vesiculosus
var. spiralis were recorded at 5 and 25 C. In the salinity
tolerance experiments, 3 replicates were used. The plants were incubated at their respective temperatures and salini
ties for 48 hours prior to their measurement. 9
DESCRIPTION OF STUDY AREAS AND ENVIRONMENTAL CONDITIONS
As stated previously, Jaffrey Point, or Fort Stark as it is commonly called, was the primary study site. It is a semi-exposed, open coastal site located approximately two miles southeast of Portsmouth, New Hampshire, on the southeast corner of Newcastle Island, latitude 43°03'33"n, longitude 70°42'42"w (Fig. 2). The shore consists primarily of large metasedimentary rock out-croppings with several intermittent small sand and gravel beaches. The metasedi mentary outcroppings have a rough texture with many large cracks and fissures. A detailed geological description of the area is given by Novotny (1969). A large biomass of fucoid algae occurs throughout the intertidal zone at Jaf frey Point which consists primarily of Fucus vesiculosus,
Ascophyllum nodosum and Fucus spiralis.
The seasonal variations in the temperatures and salinities of the surface water at high tide at Jaffrey
Point, New Hampshire are shown in Figure 3. A minimum of
3 c was recorded in December, while maximum temperatures of
18.5-19.5 C were recorded in July and August. The salinity was relatively stable from July to May, ranging from 30 o/oo to 25 o/oo; the salinities then increased again to 30-31.5 o/oo. The tidal range at spring tide varies from -0.66 to 10
3.42 m with the average tidal amplitude being +2.64 m (Anon.
1972). Further descriptions of Jaffrey Point are summarized by Mathieson, et al., (in press, a).
The Great Bay Estuary System contains over 11,000 acres of tidewater (Anon. 1960) and it is one of the largest estuary systems on the East Coast of the United States (Fig.
2). The tidal waters enter and leave via the Piscataqua
River. The Estuary System consists of Great Bay, Little Bay,
Portsmouth Harbor and its tributaries, the piscataqua River, and seven freshwater rivers, which drain into the basin.
These latter rivers are the Salmon Falls, Cocheco, Bellamy,
Oyster, Lamprey, Squamscott, and Winnicut. The total drain age area of the System is approximately 930 square miles; the estuary itself contains about 100 miles of shoreline
(Mulligan, et al., 1974). The intertidal shoreline primarily consists of scattered, metasedimentary and metavolcanic out crops, as well as scattered shingle, boulders and pebbles among muddy tidal flats. The intertidal flora is dominated by fucoid (Ascophyllum nodosum and Fucus ves iculosus var. spiralis) and crustose algae (Hildenbrandia prototypus and protoderma marinum) in association with the marine inverte brates Balanus balanoides, Mytilus edulis and Littorina littorea.
Wide fluctuations of surface water temperature and 11
salinity occur within the Great Bay Estuary System (Table I).
A description of the estuarine stations where F_. spiralis populations are found is summarized in the appendix. Further descriptions of the Great Bay Estuary System are given by
Mathieson, et al., (in press, b ) . 12
REPRODUCTION AND GROWTH OF FUCUS SPIRALIS
Figure 4 summarizes the seasonal reproduction of F.
spiralis at Jaffrey Point, expressed as the percentage of reproductive plants in the population and the percentage of
fertile tips per plant. The period of maximum reproduction occurs from June to September; prior to this period only
immature receptacles of vegetative tips were visible (Fig. 1).
Thus, the number of reproductive plants increased sharply
from May to July and the numbers remained relatively constant until September (approximately 60%); thereafter, it decreased drastically. The number of fertile tips/plant followed a similar pattern, reaching a maximum of 15% in August and declining sharply thereafter. As shown in Figure 5, repro ductive plants were 9.5 cm or longer in length during July to September. A maturation sequence is also suggested as the largest plants showed the highest percentage of repro ductive plants. Figure 5 also shows a sequential increase
in reproductive plants from July to August and a decrease
in September. Most (85-90%) of the samples were 9.5 to 24.5 cm in length.
Figure 6 illustrates the seasonal growth of tagged
in situ plants of F. spiralis at Jaffrey Point, expressed as the average increase in length per month. A maximum growth rate of 1.9-2.8 cm/month occurred during the summer 13
(June through August), while a minimal growth rate of 0.6 to 0.8 cm/month occurred from November through March. A comparison of Figures 4 and 6 shows that a fall (October) maximum of growth occurred after the termination of maximum reproduction.
Table III illustrates the annual growth of twelve in s itu plants during 1972 and 1973, while Table IV shows the growth of forty plants during July to November, 1972.
The annual growth rates of the twelve tagged plants ranged from 0.9 to 1.4 cm/month, and the yearly length increase varied from 9.9 to 15.9 cm. The growth rate from July-Nov- ember for the forty tagged plants ranged from 1.1 to 2.9 cm/ month, while the total length increase for the same period varied from 4.3 to 11.5 cm. Statistical analysis showed no correlation between the rates of growth and the initial size of the twelve and forty tagged plants (r = 0 . 2 2 and
0.06).
Figure 7 shows the seasonal survival of tagged in situ plants/months at Jaffrey Point. Three separate sets of tagged plants were employed; that is, 100 were tagged in July,
25 were tagged in December and a third set of 20 were tagged in April. There was continual loss of tagged plants after each of the three periods. Even so, the highest attrition occurred from July through September and from February to 14
March. Figure 8 illustrates the sizes at which the plants of F. spiralis were lost. The greatest attrition occurred with plants between 15 to 30 cm long. Very few plants attain a length greater than 35 cm. It should be noted that the smaller plants (0 - 1 0 cm) are inadequately represented, because they were difficult to tag.
The seasonal growth of ]?. spiralis expressed as the average weight/plant and the average weight/cm/plant is
illustrated in Figure 9. Both of the plots show the same basic pattern, with the largest plants occurring in July and August and the smallest in January. Thus, the average weight/plant varied from 37.8 to 43.9 g during July and
August to 7.0 g in January. The average weight/cm/plant ranged from 2.3 g/cm/plant in July and August to 0.5 g/cm/ plant in January. The average weight of summer plants was approximately five times that of winter specimens. 15
VERTICAL DISTRIBUTION AND BIOMASS OF F. SPIRALIS AND ASSOCIATED FUCOIDS
Figure 10 illustrates the vertical distribution and biomass of the fucoid algae at Jaffrey Point. The Eh spira lis belt is the highest within the intertidal zone ranging from +2.12 to +2.36 m above mean low water (M.L.W.). There is a transition area between F. spiralis and the Eh vesiculo- sus-A. nodosum belts at approximately +2.12 m. Even so, all three fucoids were present at this elevation, as well as
Fucus plants (Phybrids) that were difficult to identify because they were morphologically intermediate between
F. spiralis and F_. vesiculosus. There was a mixture of A. nodosum and F_. ves iculosus between +1.21 to +2.12 m. No fucoid algae were present below +1 . 2 1 m, presumably because of a lack of stable substrate. The biomass of F. spiralis varied from 250-270 g/0.25 m^ at the top and bottom of the zone to 545 g/0.25 m in the middle of the zone. The greatest biomass of A. nodosum (660 g/0.25 m^) also occurred in the middle of its zone, with lower values occurring at the lower and higher elevations. The biomass of F. vesiculosus ranged from 36 to 258 g/0.25 m 2 , with no conspicuous stratification between +1.21 and +2.12 m.
The stature and reproductive status of F. spiralis plants at Jaffrey Point also showed a vertical stratification
(Fig. 11). Thus, the average weight, length, and fertility 16 tended to decrease with an increase in elevations. The highest average length and reproductive frequency of F. spiralis occurred between +2.09 and +2.18 m. In contrast, the largest average weight tended to occur between +2.15 and
+2.27 m. Figure 12 illustrates the size frequency distri bution of F_. spiralis plants at Jaffrey Point. The largest plants (40-50 cm) occurred between +2.12 and +2.15 m. Above and below these elevations the plants were smaller. The highest frequency of small plants (0-20 cm) was recorded between +2.30 and +2.39 m. Thus, a change in size and stature was evident within the F_. spiralis belt.
Figure 13 illustrates the vertical distribution and standing crop of fucoid algae at Fort Constitution, near the mouth of Portsmouth Harbor (Fig. 2). Fucus vesiculosus var. spiralis and A. nodosum are present, but F. ves iculosus and Fb spiralis are absent. Fucus ves iculosus var. spiralis occupies the highest part of the shore between +1.82 to +2.12 m with largest biomass (503 g/0.25 m^) occurring towards the lower end of its belt. Ascophyllum nodosum is most abundant towards the lower elevations, even though Fb vesiculosus var. spiralis is still present. As at Jaffrey Point, the greatest
r y biomass (1040 g/0.25 m ) of A. nodosum occurred in the cen tral portion of the bent (+1.42 to +1.64 m). 17
HORIZONTAL DISTRIBUTION OF FUCUS SPIRALIS
Although F. spiralis is not evident at Fort Consti
tution, it extends sporadically throughout the Great Bay
Estuary System (Fig. 14). Table I summarizes the maximum,
minimum and average values for temperature and salinity within the distributional range of EL spiralis. It is
evident that FL spiralis is both eurythermal and euryhaline,
occurring within a temperature and salinity range of -0.5 C
to 23.1 C and 3.0 o/oo to 31.0 o/oo, respectively.
Figure 14 summarizes the vertical distribution (i.e.
the range) of F. spiralis at Jaffrey Point and at five inland
estuarine sites. The plant's vertical distribution was
higher and broader (+2.12 to +2.36 m) at Jaffrey Point than most of the estuarine sites except Nannie Island. Estuarine
populations of F. spiralis tend to form a compressed and often
reduced belt above F. vesiculosus var. spiralis. In addi
tion, EL spiralis was always restricted to metasedimentary
or metavolcanic outcrops, similar to those at Jaffrey Point. 18
WATER LOSS OF FUCUS SPIRALIS AND ASSOCIATED FUCOIDS
Figure 15 summarizes the rate of water loss of in situ populations of F. spiralis, EL vesiculosus, F. vesi culosus var. spiralis, and A. nodosum. The highest growing fucoid, F. spiralis, loses water more slowly than the other lower growing species. Thus, FL vesiculosus, FL vesiculosus var. spiralis and A. nodosum lose water at a similar rate of approximately 30%/hour for the first two hours, while F. spiralis showed a lower rate of approximately 15%/hour dur ing the same period. After five hours, the first three fucoids lost approximately 90% of their water content.
Fucus spiralis still had 40% of its original water content after five hours and 30% after nine hours. Individual plants of F. spiralis from top, middle and lower elevations lose water at different rates (Fig. 16). For example, a
10% difference in water loss was evident between individuals from the top and bottom of the zone. 19
MANOMETRIC STUDIES
Light
Figure 17 illustrates the rates of net photosynthe sis of Fucus spiralis, Fucus ves iculosus and Fucus vesiculo sus var. spiralis at 15 C, 31 o/oo and under varying light intensities. The net photosynthesis of F. spiralis increas ed with an increase in light intensity to about 1 0 0 0 foot- candles; beyond this intensity the rates remained relatively constant through 3000 foot-candles. Thus, light intensities of less than 1 0 0 0 foot-candles are probably suboptimal, while those in excess are probably saturating for net photosyn thesis. Fucus vesiculosus and F_. ves iculosus var. spiralis showed a similar increase in net photosynthesis with an increase in light intensity up to about 1 2 0 0 foot-candles; thus, optimal light requirements for the latter species are about 1 2 0 0 foot-candles but they show a broad tolerance to high light intensities.
Temperature
Figure 18 illustrates the rates of net photosynthesis of summer and winter specimens of F. spiralis at various temperatures, 1000 foot-candles and 31 o/oo. During the summer, the rates of net photosynthesis increased with increasing temperatures from 10 to 25 C, decreased substan tially from 25 to 32 C, and then ceased at 37 C. Winter 20 plants showed the following differences from summer plants:
(1) a higher rate of net photosynthesis between 5-30 C;
(2) a broader "plateau" between 20 and 25 C and; (3) a
reduced tolerance to high temperatures. Figures 19 and 20
illustrate seasonal temperature responses of F_. vesiculosus and F_. vesiculosus var. spiralis at 1000 foot-candles and
31 o/oo. Summer specimens of both species showed a similar
temperature optimum of about 25 C, decreasing photosynthesis above 35 C, and no photosynthesis at 37 and 40 C. Winter
specimens of F_. ves iculosus showed a higher rate of net photosynthesis between 5-30 C, temperature optima of 15-20 C, and a reduced temperature tolerance as compared to summer plants. Winter specimens of F. ves iculosus var. spiralis showed temperature response similar to that of Fh ves iculo sus , except for a somewhat broader plateau between 15-25 C.
A comparison of Figures 18-20 shows a variety of
similarities and differences between three fucoid species.
Summer specimens of _F. ves iculosus var. spiralis showed the highest temperature tolerance, with net photosynthesis still occurring at 38 C. In contrast, summer specimens of F_. ves iculosus and F. spiralis showed no net photosynthesis at
37 C. Each of the three species exhibited the same maximum temperature tolerance of 35 C during the winter. It should also be noted that F. vesiculosus and F. vesiculosus var. 21 spiralis showed a greater increase in their rate of net photosynthesis per degree centigrade during the winter than during the summer.
Salinity
The rates of net photosynthesis for F_. spiralis and
F_. ves iculosus in various salinities, 1000 foot-candles and
15 C are illustrated in Figure 21. Fucus vesiculosus showed a broad tolerance to salinity, with lowest net photosynthe sis at 0 and 10 o/oo and a relatively constant response be tween 20-35 o/oo. Fucus spiralis showed a relatively con stant rate of net photosynthesis between 15-30 o/oo, with a slight increase between 30-40 o/oo. The greatest fluctuations of net photosynthesis in both species were evident at 0-15 o/oo. Fucus vesiculosus var. spiralis showed its highest rates of net photosynthesis at 5-15 o/oo, relatively con stant rates between 20-40 o/oo, and its lowest net photosyn thesis at 50 o/oo (Fig. 22).
Salinity and Temperature
Figure 23 illustrates the raite of net photosynthesis of F. spiralis and F. vesiculosus var. spiralis at 5 and 25 C,
1000 foot-candles and after 48 hours of immersion in solutions of various salinities. Fucus spira1is showed differential tolerances to low salinities at 5 and 25 C. Thus, it showed no marked decrease in net photosynthesis with decreasing 22 salinity at 5 C, but a conspicuous decrease in net photosyn thesis with decreasing salinities at 25 C. This same differ ential salinity tolerance was not evident with F. vesiculosus var. spiralis; indeed, at 25 C the net photosynthesis was greater at 0 than at 10 o/oo. The higher rate of net photo synthesis at 5 C, than at 25 C was particularly striking, as it was the reverse of that shown in Figure 18. 23
DISCUSSION
Fucus spiralis shows a pronounced reproductive
periodicity similar to other species of fucoid algae; as
AscophyHum nodosum (Baardseth, 1970) , Fucus serratus (Le- moine; 1913; Knight and Parke, 1950) and Fucus vesiculosus
(Lemoine, 1913; Knight and Parke, 1950; Hamel, 1931). Thus,
local populations of F. spiralis from New Hampshire exhibit maximum reproduction during July to September, with a peak
in August. Subrahmanyan (1961), Williams, et al. (1965), and
Bird and McLachlan (1974) recorded a similar reproductive phenology for British and Canadian populations of Eb spiralis.
The initiation, maturation and shedding of the receptacles in New Hampshire populations of Eb spiralis usually occurs over a ten month period. The receptacles appear during late January-February, gametes are discharged during July or August, and the receptacles are subsequently
shed by November. As shown in Figure 5, young plants of F.
spiralis usually reach a length of 10 cm or more before they
form receptacles; in addition, the number of receptacles/ plant increases with the size of the plant. Subrahmanyan
(1961) recorded similar ‘observations on Eb spiralis popula tions on the Isle of Man, where the smallest reproductive plants were 8 to 10 cm long. My study also confirms Sub rahmanyan's findings that reproduction normally begins during 24 or at the end of the second year's growth. Thus, there are many similarities between reproductive phenologies of the
£* spiralis populations on the Isle of Man and in New Hamp shire .
The reproductive period of Fh spiralis occurs later in the year than with Ascophyllum nodosum and Fucus ves iculo sus . For example, the period of maximum reproduction for A. nodosum occurs during April-May (David, 1943; Moss, 1970,
Baardseth, 1970). Knight and Parke (1950) record a similar period of maximum reproduction in Eh ves iculosus, as well as the continued release of gametes in small amounts until
September. The estuarine variety spiralis of Eh vesiculosus shows a reproductive periodicity in New England similar to that of Eh ves iculosus on the Isle of Man (A. Mathieson, un published data). A comparison of the reproductive phenology of F. spiralis and F. ves iculosus also shows that there is some overlap between the two lasting into September. Burrows and Lodge (1951) have also noted an overlapping of reproduc tive periods in these two species.
Munda (1954, 1967) suggested that reduced salinities influence the reproductive phenologies of fucoid algae, and noted that the rate of fructification in A. nodosum and F. vesiculosus was accelerated in diluted sea water. Burrows
(1954) also indicated that the initiation of reproduction 25 in Eh serratus and F. ceranoides occurred in a wide range of salinities. The initiation and maturation of fertile recep tacles in F. spiralis populations in New Hampshire also occur during the spring runoff from the Great Bay Estuary System.
Unfortunately a detailed, comparative study has not been conducted on New England estuarine populations of F. spiralis.
If salinity plays a major role in determining the ripening process of Eh spiralis receptacles, as suggested by Munda for related fucoid species, then the period of maximum reproduction and the length of the fertile period might vary according to the hydrographic regimes of the habitat. The lengthening of the reproductive period of
Eh spiralis could have considerable biological significance as it would increase the reproductive overlap with F. vesiculo sus and increase the potential for their hybridization.
Burrows and Lodge (1951) emphasized that the fruiting periods of Eh spiralis and Eh vesiculosus overlapped extensively near the Mersey River in England; in addition, they noted that the area contained extensive hybrid populations between the two species. Stomps (1911) also found a similar situation on the Belgian Coast where the Chenal de l'Yser River flows into the sea at Nieuport. A variety of field and laboratory studies should be conducted to evaluate the effects of overlapping reproductive periods, salinity effects and 26 hybridization in the genus Fucus.
Several other environmental factors might also play a role in the reproductive phenology of F_. spiralis, such as nutrients, temperature and photoperiod. David (1943) speculated that a critical balance of carbohydrates and nitrogenous substances is necessary before the initiation of reproduction. Knight and Parke (1950) seem to support
David's hypothesis regarding nutrients, for they found that the earliest maturation of F. vesiculosus populations occurred near river discharges (e.g., Langness on the Isle of Man), presumably because of the extra organic matter added to the sea water. My study also showed an interrelationship between receptacles initiation and high nutrient concentrations, since the highest concentration of nitrogenous and phos phorous nutrients occurred at Jaffrey Point during January and Febraury (Norall, unpublished data). David (1943) states that cold temperatures may also induce receptacle formation in F. spiralis, since they are initiated during the winter. Fucus spiralis populations in New England and on the Isle of Man (Subrahmanyan, 1961) also show the same winter initiation of receptacles. Naylor (in Printz, 1956) suggested that photoperiodism might be a major factor determining reproductive phenology of Ascophyllum and other fucoid algae because of conspicuous latitudinal variations. 27
In contrast, McLachlan (1971) suggested that reproduction
in Fucus may be an intrinsic characteristic. The findings
of Burrows (1964) and Moss (1967, 1968) also tend to support
McLachlan's findings. Critical laboratory and field studies
are needed to evaluate the role of environmental and/or
genetic control of reproduction in F_. spiralis.
A comparison of Figures 4 and 6 shows that the re
production and growth of Fucus spiralis are synchronized,
except during the early fall when there is an "enhancement"
of growth following reproduction. Thus, the period of max
imum growth and reproduction in F_. spiralis occurs during
the late summer, while both are at minimal levels during
the winter. In contrast to my findings, Subrahmanyan (1961)
reported an alternating periodicity of growth and reproduc
tion with F_. spiralis populations on the Isle of Man. The
cooler temperature regimes in New England versus England may explain the differential growth potential of the two populations; that is, more extensive growth may occur during
the fall and winter in England because of the milder tempera
ture conditions. It is of interest to note that both David
(1943) and Mathieson (unpublished data) have also noted a similar "enhancement" of growth following reproduction with the fucoid brown algae Ascophyllum nodosum and Fucus vesiculosus var. spiralis. Such enhancement may be a 28 generalized response.
As noted previously, the seasonal growth of Fucus spiralis in New Hampshire varies from 1.9 to 2.8 cm/month
in the summer to 0.7 cm/month in the winter, with an overall monthly average of 1.2 cm/month. Subrahmanyan (1961), working with F. spiralis populations on the Isle of Man, found rates varying from 7.9 to 18.7 cm per year; this would average 13.3 cm/year or 1.1 cm/month, comparing favorably with the local growth rates. Hariot (1909) recorded lower growth rates for French populations of Eb spiralis than those recorded in England or New England - e.g., Hariot observed an average growth rate of 4.5 cm during an eight month period or approximately 0 .6 cm/month.
A comparison of the growth rates of Fucus spiralis at Jaffrey Point and Fucus ves iculosus on the Isle of Man
(Knight and Parke, 1950; Subrahmanyan, 1961) indicates that the latter species grows faster than the former. That is, the average growth rate of the mid intertidal fucoid,
F. vesiculosus, was 1.8 cm/month versus 1.2 cm/month for the high intertidal fucoid, Eb spiralis. The differential growth rates between the two species is consistent with other workers' findings (Baker, 1910; Gislen, 1930) that the rate of growth decreases with an increase in elevation.
The increased growth of Eb spiralis from April to 29
August is associated with a corresponding increase in tem perature and light (duration and intensity) conditions.
Maximum growth occurs when the surface water temperatures are 18-19 C and daylengths are about 15 hours. The latter
"optimal" conditions are similar to those recorded by
McLachlan, et al., (1971) and Sheader and Moss (1975) for other fucoid algae.
Longevity of the Fucus spiralis plants at Jaffrey
Point, New Hampshire usually ranged from 2-2.5 years; however, some plants exceeded four years. If an average growth rate of approximately 1.2 cm/month is assumed, a one year old plant would be approximately 14.4 cm long; a two year old plant would be approximately 28.8 cm long. Most of the
F. spiralis plants at Jaffrey Point varied from 0.1 to 30 cm long (Fig. 11 and 12). Similar results were also observed with the plants tagged in situ since the largest percentage
(74%) of these plants attained a length of 15 to 30 cm before they were lost (Fig. 8 ); very few plants attained a length of 30 to 45 cm (15%). The longest plants observed at
Jaffrey Point were approximately 42 cm long. The longevity of F. spiralis populations at Jaffrey Point is comparable to that found in Europe. For example, Rees (1932) and
Chapman (1968) stated that the average longevity of F. spiralis is approximately 1.5 years. Subrahmanyan (1961) 30
recorded a maximum longevity of 4 to 5 years. According to
Rees (1932), F. spiralis has a greater longevity than F.
vesiculosus or A. nodosum. In contrast, Boney (1966) stated
that the maximum life span of A. nodosum is 13-19 years in
the British Isles, with an average of 12-13 years.
As shown in Figure 7, Fucus spiralis shows two periods of major attrition: (i) during the late summer period of maximum reproduction, and (ii) during the winter period of severe storms and ice scouring. The largest losses of plants occurred during the late summer because of the heavy weight of the mature receptacles and the rapid decay of the stipe by bacterial and fungal action. It should be noted that young plants of F. spiralis can quickly replace the older, denuded plants, because of the coincidence of maximum attrition and reproduction. Subrahmanyan (1961) also recorded a high attrition in F_. spiralis populations on the Isle of Man, while Knight and Parke (1950) recorded the same phenomenon in the other fucoids. Thus, there is a correlation between the attrition, longevity, and time of reproduction in a variety of fucoids.
Fucus spiralis forms the uppermost fucoid zone at
Jaffrey Point and adjoining sites, occurring between +2.12 and +2.36 m. As a result of its extreme vertical distri bution, Fb spiralis is exposed to the air most of the time 31
(60 to 80%) , and it must resist a variety of atmospheric
extremes, such as high light intensities, temperatures and water loss. A comparison of the photosynthesis-light re
sponses of F. spiralis indicates that it is a sun plant, i.e.,
it is able to withstand a wide range of light intensities
and it has a relatively high light optimum (approximately
1000 to 1200 foot-candles). Fucus vesiculosus, F. vesi
culosus var. spiralis and a variety of other seaweeds
(Stocker and Holdeheide, 1938; and Karwisher, 1966) also show the same physiological characteristics.
The broad temperature and light tolerances of Fucus spiralis, as well as its slow rate of water loss, also substantiate its tolerances and adaptations to the high
intertidal zone. Fucus spiralis loses water at approximately one-half the rate of F. vesiculosus, Eh vesiculosus var. spiralis, and A. nodosum. Zaneveld (1937), Priou (1963) and Berard-Therriault and Cardinal (1973) also recorded a differential water loss of fucoid algae in relation to their vertical distributions. However, other workers (e.g.,
Kristensen, 1968) have shown contrary results, relating desiccation and vertical distribution. Even so, Zaneveld
(1969) emphasizes that "all measurements thus far taken point toward desiccation and its influence on photosynthesis as the main causal factor determining the upper limits of 32 vertical distribution of various eulittoral algae". The recent studies of Johnson, et al. (1974) and the earlier studies of Stocker and Holdheide (1938) substantiate Zane veld 's suggestion, for they observed that the photosynthetic rate of Fucus sp., as well as other high intertidal seaweeds, were higher under exposed than submerged conditions. It should be emphasized that the "enhancement" phenomenon described by Johnson, et al. (1974) only occurs up to a critical water content, beyond which photosynthesis decreases.
Unfortunately comparable desiccation-photosynthesis studies have not been conducted on F_. spiralis.
A stratification of biomass, stature and reproduc tion was observed within the Fucus spiralis zone at Jaffrey
Point. A differential water loss was also evident from the top and bottom; that is, small plants at the top of the zone lost water faster than larger ones from the middle and lower areas. Typically the smaller and less reproductive plants were recorded in the upper belt; the opposite was evident in the lowermost portion of the belt. Thus, there seems to be a relationship between growth (stature) and water loss, with a critical water content ultimately suppressing growth and probably net photosynthesis as well. The same relationships may also exist for reproduction, as Baker
(1910) has shown a differential zygote survival under 33 different exposure periods. Subrahmanyan (1961) and Anand
(1937) also documented a morphological stratification of
Eh spiralis plants in Great Britain. In addition, Subrah manyan noted a differential growth rate at the top (about
8 cm/year) and bottom (13-14 cm/year) of the Eb spiralis belt.
A mixture of heterogenous Fucus species ("hybrids") were recorded from Jaffrey Point at about +2.12 m. The
"hybrid"-like plants were difficult to identify as either
Eh spiralis or Eb vesiculosus. Kneip (1925), Sauvageau
(1908) and Burrows and Lodge (1951) also recorded "hybrid" fucoid populations at the transitional zone between Eh spiralis and F. vesiculosus. Burrows and Lodge (1951) emphasized that "hybrids" occur between these two species and that they would be most competitive in the transition areas between the sharply defined zones of the parents. A more detailed investigation will be required on these plants to verify that they are indeed interspecific hybrids.
Fucus spiralis is most abundant locally on semi exposed and sheltered open coastal shores (Mathieson, et al., in press, a ) . Even so, it exhibits a broad estuarine dist ribution within the Great Bay Estuary System, extending inland to areas where the temperature and salinity range from -0.5-23 C and 3-32 o/oo, respectively. Nienhuis (1975) also observed a bread estuarine distribution of Eh spiralis 34 populations in the Netherlands, where plants extended to the
10 o/oo isohaline. My manometric studies also substantiate the plant's broad tolerance to salinity, as well as tempera ture. Even so, it should be emphasized that F_. spira lis is represented by localized and discontinuous populations with
in the Great Bay Estuary System. Thus, local factors other than temperature and salinity seem to determine its sporadic estuarine distribution. The presence or absence of substra tum is probably one of the most important factors determining the local distribution of F_. spira lis. Specifically the plant was only found on coarse metasedimentary and metavolcanic rocks with an abundance of cracks and fissures. These rocks are sporadically distributed within the Great Bay
Estuary System (Novotony, 1969). Several other workers
(Chapman, 1968; Doty and Newhouse, 1954; Gibb, 1950) have also emphasized the importance of substratum in determining the horizontal and discontinuous distributions of seaweeds.
Lewis (1972) states that IT. spiralis favors a sheltered rather than an exposed habitat. The rock outcrops described above, with their many cracks and fissures, probably provide some degree of protection for developing zygotes and adult plants of F. spiralis.
My manometric experiments with Fucus spiralis des cribed above show a close correlation between the summer 35
rates of the plant and its temperature-net photosynthesis
responses. That is, the optimal temperature for net photo
synthesis during the summer occurs at approximately 25 C.
Locally the highest surface water temperatures occur during
July and August, with a maximum of 17.5 to 19 C at Jaffrey
Point and approximately 23 c within Great Bay proper (Table
I). The latter results are in accord with Ehrke's (1931)
findings that there is a correlation between the temperature
of maximum photosynthesis and the average temperature of
maximum development.
A comparison of the winter net photosynthesis-temp-
erature experiments shows that there is a decrease in the
optimal temperature to approximately 20 C. Winter plants of
F. spiralis also show higher rates of net photosynthesis
than the summer plants. Yokohama (1972) noted a similar
response for several seaweeds collected in the winter.
Zanodnik (1973) also recorded a higher rate of photosynthetic
activity for winter than summer plant populations of Fucus
virsoides that were maintained in the laboratory. He also
pointed out that there is a seasonal variation in the
chlorophyll (a and c) and carotenoid concentrations, with
the highest concentrations occurring during the winter.
A variety of other seaweeds, such as Codium (Sevane-Coriba,
1964; Fox, 1971) and Chondrus (Brinkhuris and Jones, 1974) 36 also show a seasonal variation in chlorophyll pigments; this and other physiological changes could explain the differences between winter and summer net photosynthetic results. Fucus ves iculosus and Eh vesiculosus var. spiralis show an even greater difference between their winter and summer rates of net photosynthesis. The different photo synthetic rates among the three plants may be due to the varying reproductive phenologies and ensuing pigment de gradation rates. The differences might also suggest a greater tolerance by Fh spiralis to high light and tempera ture regimes during the summer months than as shown by the other two fucoids.
The winter net photosynthesis-temperature response of
F. spiralis follows the same pattern as Fucus sp. from the
Arctic (Healey, 1972); that is, the maximum net photosynthe sis occurs at 20 to 25 C, with the photosynthetic rate at
10 C being two-thirds of the maximum. In comparing the winter and summer photosynthetic responses of F_. spiralis at 10 C, it is apparent that the winter rate is almost twice the summer rate. This phenomenon could be an indi cation of low temperature adaptation, as it would result in higher net photosynthesis during the winter. 37
SUMMARY
1. The autecology of F. spiralis in New Hampshire, U.S.A.
was investigated from 1972-1975.
2. The fertile receptacles of F. spiralis first appear
during late January and early February and they are
reproductively mature during July to September.
3. The periods of maximum growth and reproduction coincide,
i.e., both occur during the late summer. A limited en
hancement of growth follows the reproductive period.
4. The average longevity of F. spiralis populations is
approximately two years in New Hampshire, with a max
imum of about four years. Two periods of major attri
tion occur, i.e., during the late summer period of
maximum reproduction and during the winter period of
severe storms and ice scouring.
5. The growth rate, longevity and reproductive periodicity
of New England populations of Eb spiralis are comparable
with those previously recorded in Europe.
6 . A microstratification of biomass, stature and reproduc
tion was observed within the F. spiralis zone at Jaffrey
Point, New Hampshire.
7. The desiccation rates of _F. spiralis and associated
fucoid algae was evaluated. Fucus spiralis shows a
very slow rate of water loss, in comparison to the 38
other fucoid algae.
8 . A summary of the vertical and horizontal distribution
of F. spiralis within the Great Bay Estuary System is
given. The presence or absence of substratum is sug
gested as a causal factor for the sporadic estuarine
distribution of F_. spiralis.
9. Manometric studies on F. spiralis were undertaken in
relation to varying light intensities, temperatures
and salinities. Fucus spiralis has a broad tolerance
to all three of these parameters, corresponding to
its estuarine and vertical distribution.
10. Comparative manometric studies were also made on IT.
vesiculosus and F. ves iculosus var. spiralis. Both
of these species also showed a broad tolerance to
temperature, salinity and light regimes.
11. Fucus spiralis, F. ves iculosus and F. vesiculosus var.
spiralis showed pronounced differences in their net
photosynthesis-temperature responses during the winter
and summer. Several reasons for this seasonal difference
are discussed. 39
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APPENDIX
STATION DESCRIPTIONS
Jaffrey Point (Station #1): A semi-exposed, open coastal
area located on the southeast corner of Newcastle
Island approximately two miles from Portsmouth, New
Hampshire. The intertidal area primarily consists
of massive metasedimentary rock outcrops and scatter
ed boulders; small coarse gravel occurs in a few
localized areas.
Schiller Power Plant (Station #2): An estuarine site on the
Maine side of the Piscataqua River across from the
old Schiller Power Station. The substrate consists
of rock outcropings similar to those at Jaffrey
Point, as well as boulders, cobbles and mud.
Dover Point (Station #3): An estuarine tidal rapid site at
the junction of the Piscataqua River and Little Bay.
The intertidal area consists of massive rock pilings,
boulders, cobbles and mud.
Fox Point (Station #4): An estuarine site in Little Bay
opposite the mouth of the Oyster River. The substrate
consists of residual pileage from an old bridge,
boulders, cobbles and mud.
Adams Point (Station #5): An estuarine area approximately
4.5 miles southeast of Durham, located at the 46
junction of Great Bay and Little Bay, and the site
of the Jackson Estuarine Laboratory. The substrate
consists of small rock outcrops as well as scattered
boulders and mud.
Nannie Island (Station #6): A small island located in the
southeast corner of Great Bay, opposite Woodman
Point. The intertidal area consists of small rock
outcrops, scattered boulders, shingle and mud. 47
TABLE I
HYDROGRAPHIC DATA FOR STUDY SITES DURING 1973-1974
Miles Temp. (°C) Sal. ( i/oo) (Nautical) STATIONS _ Inland from Min. Max. X Min. Max. X Open Coast
1) Jaffrey Point 2.5 17.5 9.8 27.0 32.0 29.4 0.0
2) Schiller Power Plant 1.5 18.0 10.2 20.0 31.0 26.6 5.1
3) Dover Point 0.2 22.0 11.1 3.0 29.0 16.8 7.5
4) Fox Point 0.0 22.2 11.2 8.0 30.0 22.7 9.1
5) Adams Point -0.5 23.1 11.3 11.0 30.0 22.6 11.3
6) Nannie Island 0.0 23.0 11.5 8.0 30.0 20.4 12.6 48
TABLE II
ASW SALINITY CHART
Salinity Ratio 500 ml 2m ASW w/o Buffer 2X ASW Distilled Buf f er o/oo to (ml) H20 0.1 molar 0.1 molar Distilled Water -Buffer (ml) NaH Co. 4 NaCo-, (ml) (ml)
0 0:1 0 420 75 5
5 1:11 35 385 11 it
10 1: 5 70 350 II 11
15 1:3 105 315 11 II
20 1:2 140 280 •. 1 11
25 5:7 175 245 11 it
30 1:1 210 210 II 11
35 7:5 245 175 11 H
40 2:1 280 140 • i it
45 3:1 315 105 11
50 5:1 350 70 11 49
TABLE III
ANNUAL GROWTH OF TWELVE TAGGED PLANTS OF FUCUS SPIRALIS. JUNE 1972-JUNE 197 3
Initial Final Total Growth Rate Length Length Increase per month (cm) (era) (cm) (cm)
11 18.0 30.8 12.8 1.2
14 10.0 22.6 12.6 1.1
16 19. 5 32.1 12.6 1.1
28 11.0 26.9 15.9 1.4
38 27.0 41.5 14.5 1.3
51 14.0 27.4 13.4 1.2
80 14. 5 25.6 11.1 1.0
85 14.4 24.5 10.1 0.9
86 14.7 24.6 9.9 0.9
89 12.8 23.7 10.9 1.0
93 13.9 27.6 13.7 1.2
99 15.8 30.3 14.5 1.3 50
TABLE IV
FORTY TAGGED PLANTS OF FUCUS SPIRALIS JULY 1972-NOVEMBER 1972
Initia1 Fina 1 Total Growth Rate Length Length Increase per month (cm) (cm) (cm) (cm)
2 14.0 19.7 5.7 1.4
9 17.0 26.1 9.1 2.3
10 14.2 21.3 7.1 1.8
11 18.0 24.9 6.9 1.7
12 14.6 20.7 6.1 1.5
14 10.0 15.5 5.5 1.4
15 12.9 17.2 4.3 1.1
16 19.5 26.5 7.0 1.8
19 17.5 24.3 6.8 1.7
20 16.5 28.0 11.5 2.9
22 14.3 23 .0 8.7 2.2
23 10.4 18.4 8.0 2.0
25 13.2 21.6 8.4 2.1
26 18.2 28.4 10.2 2.5
27 10.0 16.9 6.9 1.7
28 11.0 19.3 8.3 2.1
33 18.0 25.2 7.2 1.8
17 .0 24.2 7.2 1.8
27.0 35.1 8.1 2.0 51
IV continued:
Initial Final Total Growth Rate Length Length Increase per month (cm) (cm) (cm) (cm)
39 17 .0 23 .6 6.6 1.6
43 36.4 42.2 5.8 1.5
45 15 .2 20.1 4.9 1.2
65 13.2 18.9 5.7 1.4
66 10.7 19.3 8.6 2.2
68 13.3 22.5 9.2 2.3
77 22.8 32.7 9.9 2.5
78 18.1 24.6 6.5 1.6
79 18.3 27.7 9.4 2.3
80 14.5 20.5 6.0 1.5
84 20.2 27.0 6.8 1.7
85 14.4 23 .5 9.1 2.3
89 12.8 18.9 6.1 1.5
90 11.9 19.3 7.4 1.9
93 13.9 20.8 6.9 1.7
94 14.0 21.7 7.7 1.9
95 12.8 21.0 8.2 2.1
96 13 .0 21.0 8.0 2.0
97 18.4 27.1 8.7 2.2
98 25.8 33.7 7.9 2.0
15.8 25.0 9.2 2.3 52
Figure 1 Morphology and Reproductive Development of Fucus spiralis. V
> -j > J ^ > • jb&jyzc..' •"
CD
m -
u 54
Figure 2 Map of the New Hampshire Seacoast and Study Sites. MAINE 43 * 0 7 :
LITTLE BAY
“ V 7 - i o f t . constitutio
GREAT BAY 6 • JAFFREY POINT
ATLANTIC NEW HAMPSHIRE OCEAN
43 0 0 -
[70 * 5 6 ' 7n'Al' (Ji (Ji 56
Figure 3 Variations in Surface Water Temperatures and Salinities at Jaffrey Point, New Hampshire, July 1972 to September 1973. Salinity o «o O «/o O N CO CO 00 O >n CN uo O ) ejniDJodtuoX ' o 58 Figure 4 Seasonal Reproductive Phenology of Fucus spiralis Plants at Jaffrey point, New Hampshire, during 1972. r-100 fertile tips J F M A M J J A 1972 U1 U3 6 0 Figure 5 Stature and Reproductive Frequency of Fucus spir alis plants at Jaffrey Point, New Hampshire, July to September 1972. c. of plants of % Fertile tips/plant % _.KJCJt*.CnO''J00'O _rOO>l». _.KJCJt*.CnO''J00'O ooooooooooooooo o -o K) Cft o> Ln FO o Ln •o K> Ln .'O K) 1 9 Length ( 62 Figure 6 Average Monthly Growth of Tagged iri situ Fucus spiralis Plants at Jaffrey Point, New Hampshire, July 1972 to August 1973. AVERAGE LENGTH {cm) INCREASE/MONTH > (_ <_ 1972 e9 6 4 Figure 7 Seasonal Survival of Tagged in situ plants of Fucus spiralis at Jaffrey Point, New Hampshire, July 1972 to July 1973. NUMBER OF SURVIVAL PLANTS 100 90 20 40 60 80 30 50 70 A O D F J D N O S A J TAGGED 1973 PLANTS 0 0 1 0 2 5 2 A J A S A J J M A M ^ «#• a# a • # « j^a __ -- .. ui a\ 6 6 Figure 8 Size-Frequency Distribution of Lost Tagged plants of Fucus spiralis at Jaffrey Point, New Hampshire. OF PLANTS LOST 40 30 20 °0 5 10 I E NEVL (cm) INTERVALS SIZE 15 20 25 30 35 40 45 50 6 8 Figure 9 Seasonal Growth of Fucus spiralis plants at Jaffrey Point Between July 1972 and 1973. 6 9 Avorage-weight(g)/ length(cm)/plant O o CM CO o CM CM o o d O CO < “> *"> £ a. < o> £ Q Z o co a. < CM fM O o o o o o o o >o ''I CO CM o 4UD|d^/(6) Figure 10 Vertical Distribution and Biomass Variations of Fucoid Algae at Jaffrey Point, July 1973. F. spiralis I 1 800 n F.vesiculosus I—H CM A.nodosum I— 1 IT)E CM Fucus sp. t._ i 400 - 1 200 - G o JE c o D > Distance (meters) Figure 11 Vertical Stratification of Average weiihts, : **r. 1 and Reproduction Status of Fucus spiralis ?-'p,:. 1 tions from Jaffrey Point, New Hampshire, Jir.e 1 Elevation (meters) g /o .25m 200 • 400 600 800 2.5 2 1.5 - 1 0 . . 0 0 - - itne meters) ( Distance as. A. nodosum A. uu sp. Fucus F.spiralis F.vesiculosus 72 Figure 11 Vertical Stratification of Average Weights, Lengths and Reproduction Status of Fucus spiralis Popula tions from Jaffrey Point, New Hampshire, June 1974. q/o.03m2 cm % of fertile tips/plant 40 60* 30-i 0 50- 20 20 0 30 - 0 Average ^ ^ ® 10 10 - 5 0 1 -- - - - j vrg length Average vrg weight Average OC CO CO CO CM CD MCM CM CD % f reproduction of 00 lvto ( eters) (m Elevation CO CM O CM CM r" CM CM •c- m c csi 0LO 00 MCM CM — r CM MCD CM T— o CM 74 Figure 12 size Frequency Distribution of Fucus spiralis Plants at Different Elevations at Jaffrey Point, June 1974. 2.39 m 50 - 2.21m 3______ 2.36 2.18 5 0 - 0 2.30 2.15 50 _oc a 'o 0 & 2.12 2.27 50 0 2.24 50 H 2.09 0 10 '20. 30 4 0 50 0 10 20 30 40 50 Length (cm) 76 Figure 13 Vertical Distribution and Biomass Variations of the Fucoid Algae at Fort Constitution, July 1973. Elevation (meters) g/o.25m 1200-1 0.6 2 . 0 - 0 . vsclss a. prls I I I 1 spiralis var. F. vesiculosus A. nodosum A. itne (meters) Distance' 2 3 4 Sand 5 vj 7 8 Figure 14 Horizontal and Vertical Distribution of Fucus spiralis Within the Great Bay Estuary System. STATION ADAMS ADAMS POINT NANNIE IS. JAFFREY JAFFREY POINT DOVER DOVER POINT SCHILLER SCHILLER POWER FOX POINT M tn ro O (METERS) CJl ELEVATION O cn K > - CO - CO fO o- ro cn - ro _ ro ro . O• cn oo KILOMETERS L 6 8 0 Figure 15 The Cumulative Water Loss of in situ Plants of Fucus spiralis. F. vesiculosus. F. vesiculosus var• spiralis and A . nodosum. % of water loss n 100 20 40 - 60 - 80 - - 0 2 or o exposure of Hours 4 .vsclss a. spirali: var. F. vesiculosus F. vesiculosus F.spiralis A. nodosum A. 6 7 8 93 5 10 8 2 Figure 16 The Cumulative Water Loss of in situ Plants of Fucus spiralis from Different Elevations. i 100 n ...W-fT-T* Top — Middle — Bottom — i 4 5 6 7 8 10 Hours of exposure 05U> 8 4 Figure 17 Net photosynthesis of Fucus spiralis, F. vesiculo sus and F. vesiculosus var. spiralis at Various Light Intensities and 15 C. 6 0 i F. spiralis F. vesiculosus F. vesiculosus var. spiralis 1 " I' i i i I I 2000 3000 Light (foot-candles) 8 6 Figure 18 Net Photosynthesis of Winter and Summer Plants of Fucus spiralis at Various Temperatures, 1000 foot- candles. pi Oj /9 dry wgt /0.5 mic 120 100 110 20 60 0 O. 27,1973 NOV. U. 21,1973AUG. 5 10 15 eprtr C Temperature 20 25 035 30 00 8 8 Figure 19 Net Photosynthesis of Winter and Summer Plants of Fucus vesiculosus at Various Temperatures, 1000 foot-candles. 130 -i 120 - 110 - 100 c 90 oE 80 % X 70 H "Dk. 60 50 - 40 - 30 AUG. 28, 1973 20 - NOV. 29, 1973 10 - 0 X 5 15 20 o Temperature C oo VO 90 Figure 20 Net Photosynthesis of Winter and Summer Plants of Fucus vesiculosus var. spiralis at Various Temperatures, 1000 foot-candles. Temperature C 10 1 9 7 3 1973 Y NOV. 3 0 . AUG. 2 2 , 0 5 - - - - - 0 10 20 30 - 4 0 - 5 0 - 80 - 6 0 7 0 “ 9 0 - 100 110 130 120 uiuis o/'tM Xjp 6/lO\d 92 Figure 21 Net Photosynthesis of Fucus spiralis and Fucus vesiculosus in Various Salinities and 15 C. C pi 0 3/ q dry wyo.Smin. pi 0 ,/g dry w»./o.5mi 1 0 0 1 100 100 -i 60- 80- 0 - 60 40 0 - 80 40 spidi ird p .s F 0 F. vesiculosus 45 5 10 15 20 aiiy o % Salinity lnt %o % alinity S 25 25 3530 540 35 045 40 50 5030 CO 94 Figure 22 Net Photosynthesis of Fucus vesiculosus var. spiralis in Various Salinities and 15 C no-, 100- 90 - | 80 - w» < 7 0 - t 60- r« O 3. 30- F.vesiculosus var. spiralis 20 0 5 10 15 20 25 30 45 50 Salinity °/o o *s> ui 96 Figure 23 Net Photosynthesis of Fucus spiralis in Various Salinities, 5 and 25 C. 30 20 ° /o o Salinity 10 25 C F.vesiculosus var. spiralis F.vesiculosus 0 •u i u i s'o/'J m Xjp 6 /lOI^ 30 20 Salinity ^oo 10 2 5 C F.spiralis 0 20 80 40 6 0 100 ujlus o/' jm Xjp ^ /eQ 1^ •n > o Z o >