Diane Campbell, Temperature and habitat effects in Dodeca
ria fewkesi. p. 2
INTRODUCTION
Dodecaceria fewkesi, a small cirratulid polychaete, inhabits envi-
ronments ranging from the mid-intertidal to subtidal depths of at least 90
feet. Berkeley and Berkeley (1954) have reported that it forms single-sex
colonies by asexual reproduction and lives in reef structures consisting
of masses of calcareous tubes. Colonies from various habitats differ in
the external structure of the tube masses and in the size of the animals.
Any given asexual colony must have been subjected to the same environmental
conditions for many decades. Because both the environmental conditions and
the morphology differ between habitats, it is likely that animals from
various habitats show physiological differences as well.
For a wide variety of organisms, subtidal animals have higher respi-
ratory rates over a wide range of temperatures than intertidal ones. Com-
parisons of rates between animals from various habitats have been made for
few polychaetes. Magnum (1972) has found that intertidal species of
onuphids have a higher 00 than intertidal ones. That study, however.
has compared different species, rather than subsets of the same, so that
differences due to habitat cannot be distinguished from habitat-independent
genotypic ones. Differences in respiratory rates between different popu-
lations of a single species can be attributed in part to short term and
long term acclimation to local temperature regimes. Studies on temperature
acclimation have been done for many animals, with different species showing
different patterns of response. Little work has been done on acclimation in
poychaetes. Magnum (1972) has shown that intertidal onuphids do not
acclimate, and Gladfeller (198) reports that the cirratulid, Cirriformia
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 3
spirabrancha acclimates to 7°0.
This study was undertaken to compare both physiologically, but with
emphasis on respiration, and morphologically, D. fewkesi from various
habitats. The following characteristics were looked at:
1. Morphology and size of the animals, the pattern of tube construction,
and mineral composition of the tubes.
2. Heat stress tolerance.
3. Respiratory rate / temperature curves and the 9 values for these.
4. Acclimation to experimental temperature regimes as measured by res¬
piratory rate.
MATERTALS and METHODS
General Descriptions:
Portions of Dodecaceria fewkesi colonies were removed with hammer
and chisel from three locations: Rocks between the O and 11.0 foot tide
levels at the east end of Agassiz beach at Hopkins Marine Station (HMS),
-10 feet on a piling below Wharf Two in Monterey, and at about -65 feet
on the reef-like area seaward from HMS. Wet body weight was determined
for groups of 5 animals each for 11 groups of intertidal worms, 14 groups
of wharf ones, and 4 groups of deep reef ones. Numbers of tentacles were
counted for 8 intertidal, 11 wharf, and 10 deep reef worms. Whether
the vast majority of tubes was vertical or irregular in direction was
noted for each colony. The maximun extension of newly growing tubes
above the level of the rest of the tube mass was measured as well. Sex
was determined by penetrating the integument with a dissecting needle
and watching for release of gametes under a dissecting scope.
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 4
Tube composition:
Percent magnesium in the tube material was determined by dissolving
washed, dried, and powdered samples in dilute HCl, and precipitating
out all alkaline earths except magnesium by the addition of ammonium
carbonate solution. The filtrate was then assayed for magnesium by the
method of Skoog and West (1965). Controls of known MgCo/CaCo were
also run to determine the accuracy level of the test.
Respiration:
Colony samples, each seventy-five ml and containing about 40 to 200
animals, from the intertidal and the wharf were maintained at 6° - 2',
0 f 1.5°, and 20?C - 3°C in finger, bowls of seawater. Colonies to be
kept at 20 were eae partitioned between two finger bowls to reduce
fouling; in the other temperatures each entire colony was kept together.
Additional animals were moved back and forth from 6% to 20' every day
except Sunday. The water was changed at least once a day except for on
two Sundays. For each temperature regime 120 intertidal worms were also
removed from their natural tubes and placed in closed end holes drilled
in plexiglass 1.27 cm deep and 0.23 cm in diameter, so that both their
heads and hind ends extended out the open ends as they do under natural field
conditions. Both number of deaths and the amount of skin pigment released
when animals were transferred to room temperature seawater were noted
after one and two weeks.
Respiratory rates were measured for each group either one or two
days after they were brought to the lab and placed in 12' running seawater,
and after both one and two weeks in the various temperature regimes. The
Warburg constant volume method was used to measure rates at 6.1', 12.0,
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 5
and 19.0°C - O.1°C. Animals were removed from their tubes with chisel
and hammer, dropped on filter paper for about 30 seconds until excess
moisture was gone before weighing, and placed in Warburg vessels containing
artificial seawater isotonic with local seawater. Gasior (1976) showed
that respiratory rates of D. fewkesi removed from their tubes and in
their natural tubes were no different. Four or five replicate vessels
were run for each experiment with five animals per vessel. Respiratory
rates were measured at 30 minute intervals for two hours at each temperature
with a two hour adjustment period in between. This adjustment period was
found to be sufficient for the animals to reach a new stable respiratory
rate. Each experimental run was started between 7:30 and 9:30 A.M. Res¬
piratory rates of one additional group of intertidal animals obtained
from the field 4 weeks later were determined at 6.1 12.0°, 19.0°, and 25.0°c.
The temperature was returned to 6.1°C over a period of 4 hours and the
rate was remeasured.
RESULTS
There is no positive evidence for temperature acclimation over a
two week period in animals from either the wharf or the intertidal. No
respiratory rate / temperature curve measured after two weeks for any
one group of animals is significantly different from the pre-acclimation
one for animals from the same habitat, with the exception that intertidal
animals maintained at 6°0 in their natural tubes for two weeks increased
their respiratory rates. This increase is significant according to the
Student t-test (p(0.05) when measured at 6.1° and 19.0°C. (Figure
1 and table 1 for intertidal animals; figure 2 and table 2 for wharf
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 6
animals.) However, both variation in weight between animals and any
weight changes over the two week period must be taken into account. Wharf
worms kept at 20° or cycled from 6° to 20°C lost about 5%% of their weight.
When respiratory rates are recalculated assuming all weight change was
due to water loss, the differences between pre-acclimation and post-accli¬
mation lines are more than compensated for. Intertidal worms kept at 6
were considerably smaller than the pre-acclimation sample. That no weight
loss occurred is indicated by the facts that,contrary to wharf worms,
for intertidal ones this is the only smaller group, this group alone was
taken from the sparsely populated edge of a colony, and animals kept at
6° in plexiglass are as heavy as the pre-acclimation sample. In addition
wharf animals which lost weight showed tightly drawn skin and loss of
pigment and died soon after, whereas intertidal ones kept at 6' appeared
healthy. Since these animals were then probably smaller to start with,
and smaller animals generally have higher respiratory rates, their respiratory
rates were adjusted to the average pre-acclimation weight according to the
expression R - (W./W)'-bR,, where W,- average weight of an animal kept
at 6°, W - average weight of pre-acclimation animals, R. - measured
respiratory rate, and the coefficient b - 0.64, that of the closest relative
for which it has been determined, Cirratulus cirratus, as measured by
Courtney (1958). The corrected rate / temperature curve was still higher
than that for pre-acclimation animals, but the difference, as for the
case when it is corrected according to the other possible assumption for
the cause of weight difference, was no longer significant. In addition,
the rate / temperature curve for animals kept at 6° in plexiglass was
not significantly higher than the pre-acclimation curve.
Animals from the three habitats react differently to heat stress.
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 7
When kept in an incubator at 34 to 35°C, 20% of the deep reef worms
died after two hours and 40 minutes, 20% of the wharf ones died after
six hours, and after eight hours no intertidal animals had succumbed.
At 37°0 20% of the deep reef worms died after two hours, and after about
five hours 60% of the deep reef worms, 53% of the wharf worms, and no
intertidal ones had died. No difference in death rates between animals
that had been kept at different acclimation temperatures was readily
apparent. Various temperatures produced many less severe effects in
the worms as well. At 6°C D. fewkesi did not extent its tentacles fully,
but no deaths occurred, at 12' it extended them fully and moved them
slowly, and when kept at 20° for several days nearly all the animals
moved out of their natural tubes and showed increased tentacle movement.
Nearly all wharf animals kept at 20 % died after 1.5 to 2 weeks. When
placed on filter paper for a few seconds and then put in seawater at room
temperature, healthy wharf, but not intertidal, animals released a greenish
yellow pigment through their skin which turned dark blue or black and
precipitated after a few hours. Wharf worms put in 12' seawater put out
no pigment. The temperature in which the animals were maintained influenced
the amount of pigment released when put in room temperature water after
two weeks. (Table 3)
The 00 values calculated for the temperature range 12° to 19' are
higher than those for the range 6.1 to 12° for animals from all three
habitats for which respiratory rates have been measured one or two days
after they were collected. This difference is significant at the p « 0.07
level according to the Student t-test for deep reef and intertidal
animals. If data from experimental runs for all groups of worms from a
given habitat, regardless of acclimation temperature, is pooled, this
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 8
difference is significant for animals from all three habitats. (p «0.01) (Table 4)
The o for the one group of intertidal worms tested at 25° was 4.32 f 2.30
at 19.° to 25°, higher than 3.61 + 1.34 found at 12° to 19°, but not sig-
nificantly so. When these animals were returned to 6.1° from 25°, their
new respiratory rate was not significantly different from the rate obtained
at 6.1° for all intertidal groups.
The respiratory rate / temperature curves appear fairly similar for
animals from all three habitats, although the rates of subtidal animals
are slightly higher. Only data from animals freshly collected or main-
tained in running seawater at 120 was included in the calculations. The
difference is significant only when measured at 12°. (Student t-test.
p (0.01) The respiratory rates were corrected for weight relative to
each other according to the expression (w./w)-br., in which W - average
weight of animals from all three habitats. When corrected, the rates of
both subtidal populations were significantly higher than the rates of the
intertidal one at all three temperatures measured. (All p (0.01) The
wharf and deep reef rates were not significantly different at any temper-
ature. (Figure 3)
External as well as physiological differences for wharf and deep
reef versus intertidal animals were found. Wharf and deep reef animals
weigh considerably more than intertidal ones, have more tentacles, and
extend their individual tubes farther above the mass surface level of
the "worm rock". (Table 5) This agrees with results of a study by Kauhaner
(1976) in which larger sample sizes were used. Wharf and deep reef worms
also produce tubes protruding in many directions to form a cluster and
live throughout the calcareous rock, whereas intertidal ones secrete
tubes mostly in parallel with the openings pointing straight up and live
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 9
only near the top. Tube samples from both the intertidal and deep reef
contain less than 1% magnesium. Kauhanen (1976) has shown that these
animals do secrete their own tubes with an extension to artificial tubes
noticeable after about three weeks.
DISCUSSION
Intertidal Dodecaceria'ability to survive extreme heat stress seems
adaptive. Bolin and Abbott (1963) state that the average temperature
difference between surface waters and the -65 foot level is only about
two degrees during the spring. However, they indicate that the difference
in maximum temperatures is about four degrees; the difference in maximum
temperatures Dodecaceria from differing colonies is exposed to is pro¬
bably much greater, as the intertidal colony studied is exposed to am¬
bient air and sunlight at most low tides. Thus it makes adaptive sense that
intertidal animals can cope with heat stress better than the subtidal ones.
Wharf animals appeared to cope slightly better than deep reef ones at
extreme high temperatures, which is consistent with the expectation that
wharf ones are acclimatized to a temperature range a few degrees higher.
Temperature stress increases the release of a pigment which Dales
(1959) has shown to be a carotenoid stored in cells in the skin. This
suggests that heat alters the permeability properties of the cell mem-
branes in the skin. However, since the water in finger bowls with
colonies at 20° became foul and presumably concommitantly lower in 0,
tension, particularly for wharf animals, any changer in pigment, weight, and
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 70
respiratory rates could all be due to 0, as well as temperature stress.
That no group of animals acclimated to a noticeable degree over a
two week period seems adaptive when their mode of life and habitat are
considered. D. fewkesi is a sedentary poychaete and spends its entire
life in one location's temperature regime. Temperature at the wharf lo-
cation probably changes little and slowly with the seasons, so that if
wharf animals acclimate to any noticeable extent they probably do so
over a longer period and only within a smaller temperature range. The
intertidal animals cope with as large of a temperature range daily as
they were subjected to in the lab. Hence it might be non-adaptive for
them to acclimate in their physiological processes by synthesizing new
isozymes so that reaction rates are substantially changed. The possibility
that they acclimated to a slight degree beyond the accuracy of the measur-
ment techniques used remains.
The 9., was found to increase with temperature in D. fewkesi, whereas
for basal metabolism in most animals it either decreases or remains
constant, Precht (1973). Noted along with this increase in 0 was
an increase in tentacle movement at higher temperature, so that these
rate / temperature curves are probably for active metabolism. This is
supported by Coyer and Magnum's (1973) work in which they found an in-
crease in 9,, with temperature for active metabolism but not basal me-
tabolism in Diopatra cuprea. They also found this uncommon phenomena
of increasing 90 with temperature in Amphitrite ornata, another poly-
chaete, for active and resting metabolism over small temperature ranges.
D. fewkesi's rate curve indicates it is very sensitive to temperature
changes in the range it normally lives in. The adaptive significance
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 17
of this is unknown.
The larger subtidal animals tested showed similar although slightly
higher rates than the intertidal ones. Most species show the opposite trend,
a decreasing rate with increasing size, Prosser (1973). Therefore, either
the respiratory rate of D. fewkesi is not influenced by size, or the
subtidal animals have higher weight specific metabolic rates. When a
weight correction factor is introduced, the difference between subtidal
and intertidal animals is greatly amplified. The difference could be
due either to adaptation to different temperature regimes or to a genetic
difference between clones not necessarily correlated with habitat. Harrold
(1976) arguesthat in the marine gastropod, Crepidula adunca, the minimum
environmental temperature is of primary importance in setting respiratory
rates, while Heath (1963) states that some fish respond to the upper ex-
treme of the thermoperiod. Both the average maximum and the amount of
change in temperature differ between subtidal and intertidal locations,
so the animals could have adapted to different temperature regimes. It
is also possible that the larger number of tentacles present in subtidal
races may compensate partly for the usual decrease in respiratory rate
with size. Gladfeller (1968) suggests this as an explanation as to why
respiratory rates fall little with size in Cirriformia spirabrancha. Data
on additional clones is needed to differentiate among the explanations
given.
That physiological differences between animals from various habitats,
such as in respiratory rate, may exist is supported by other differences
seen between the clones from different environments. The multi-directional
arrangement of the subtidal colonies may be due to water circulating in all
directions in the subtidal locations. Vertical tubes in the intertidal
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 12
would allow water to remain in them when the tide goes out. Tubes from
the intertidal have shorter extensions than ones from the two subtidal
locations, perhaps because forceful wave action wears down this relatively
fragile structure. One similarity found between intertidal and deep reef
tubes was their lack or near lack of magnesium. This, however, could
certainly be controlled by different factors than the other character-
istics are. Lowenstam (1954) found that magnesium concentration correlates
with decreasing environmental temperature, with species with more than
85% aragonite (the mineral form with less than 1% magnesium) confined to
the tropics. This trend was not followed in some habitats, and D. fewl
appears to provide one of many exceptions to it.
SUMMARY
1. Tube morphology, tentacle number, and body size varies between animals
from various habitats. Magnesium content of the tubes is constant.
2. Over the range 6.1° to 19°0, the 90 for respiratory rates of D. fewkesi
increases with increasing temperature.
3. The intertidal animals tolerate heat stress better than deep reef
and wharf animals, as is indicated both by higher survival rates and
by lesser amounts of carotenoid skin pigment released.
4. No positive evidence for acclimation in either wharf or intertidal
animals to 6°,12°,20°C, or a variable temperature regime over a two
week period was obtained.
5. Respiratory rate / temperature curves for the larger subtidal animals
are fairly similar or slightly higher than that for intertidal ones.
Diane Campbell, Temperature and habitat effects in Dodecaceri
ja fewkesi. p. 1
This was interpreted to mean that subtidal animals have a higher effective
rate than intertidal ones.
Temperature
and habitat effects in
eri
wkesi.
D. Campbell
ACKNOWLEDGMENT
I wish to thank Dr. Robin Burnett for his unlimited support, en-
couragement, and patience.
p. 14
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 15
REFERENCES
Berkeley, E. and C. Berkeley. 1954. Notes on the life-history of the
poychaete Dodecaceria fewkesi. J. Fish Res. Bd. Canada 11 (3): 326-334
Bolin, R.L. and D.P. Abbott. 1963. Studies on the marine climate and
phytoplankton of the central coast area of California, 1954 - 1960.
California Cooperative Oceanic Fisheries Investigations
Courtney, W.A.M. 1958. Certain aspects of the biology of cirratulid
poychaetes. PhD dissertation, University of London
Coyer, P.E. and C.P. Magnum. 1973. Effect of temperature on active and
resting metabolism in polychaetes. in Effects of Temperature in Ecto¬
thermic Organisms. Wieser, W, Ed. Springer-Verlag N.Y.
Dales, R.P. 1963. Pigments in the skins of the polychaetes Arenicola,
Abarenicola, Dodecaceria, and Halla. Comp. Biochem. Physiol. 8: 99-108
Gasior, B. 1976. Respiratory rates in Dodecaceria fewkesi under different
experimental conditions. (Unpublished MS on file at Hopkins Marine
Station library)
Gladfeller, E. 1968. Certain aspects of the respiration rate of the
rriformia spirabrancha. (Unpublished MS on
cirratulid poychaete, C.
file at Hopkins Marine Station library)
Harrold, C. 1976. The effect of habitat and acclimation temperature
upon the respiratory rate of the marine gastropod Crepidula adunca. In press
Heath, W.G. 1963. Thermoperiodism in sea-run cutthroat trout. Science
142: 486-488
Kauhanen, G. 1976. Comparative studies of colonial morphology and the
effects of selected environmental stresses on spatially separated Dodecaceria
fewkesi. (Unpublished MS on file at Hopkins Marine Station library)
Diane Campbell, Temperature and habitat effects in Dodecaceria fewkesi. p. 16
Lowenstam, H.A. 1954. Environmental relations of modification compo¬
sitions of certain carbonate secreting marine invertebrates. Proc.
Natl. Acad. Sci. U.S. 40: 39-48
Magnum, C.P. 1972. Temperature sensitivity of metabolism in offshore
and intertidal onuphid polychaetes. Marine Biology 17: 108-114
Precht, H, J. Christophersen, H. Hensel, and W. Larcher. 1973. Temperature
and Life. Springer-Verlag N.Y.
Prosser, C. L . 1973. Comparative Animal Physiology. 314 edition.
W.B. Saunders Co. Philadelphia
Skoog, D.A. and D.M. West. 1965. Analytical Chemistry. Holt, Rinehart
and Winston, Inc. U.S.A.
p. 17
Temperature and habitat effects in Dodecaceria fewkesi.
D. Campbell
Figure 1. Respiratory rate / temperature curves of intertidal animals.
Respiratory rate is calculated as ul 0, consumed per gram wet weight per
hour. Error bars were omitted for clearer comparison of curves.
+ Animals from the field
o Animals kept at 12°0 for two weeks
□ Animals kept at 6'0 for two weeks in their natural tubes.
....Respiratory rates corrected for weight for animals kept at 6°0 for two weeks
—-—-Animals kept at 6°C for two weeks in plexiglass tubes
• Animals kept at 20 C for two weeks
Animals cycled between 6 and 20 Cfor two weeks
Temperature and habitat effects in Dodecaceria
20




—e
15


20
Temperature c)
80

ewkesi.

p. 18
190
Temperature and habitat effects in Dodecaceria fewkesi.
D. Campbell
TABLE 1
INTERTIDAL ANIMALS
Respiratory rates (ul O, consumed/g/hr)

Fest temperatures
19.00c
12.0°c
6.100
X 8
IX x
X
X

4 82.0 7.3
5 33.6 3.7
Freshly collected
5 24.9 5.5
4 42.0 13.6
3 117.2 24.5
3 51.9 20.5
Acclimated at 6°0
in natural tubes
4 38.2 12.4
3 47.2 18.7 3 106.7 22.3
Corrected for weight
4 26.1 10.1
3 42.4 4.6 4 80.9 4.9
In plexiglass tubes
5 32.9 4.1 5 90.5 23.4
5 30.5 10.8
Acclimated at 12°0
5 42.1 8.8 5 87.4 20.7
Acclimated at 19°0
5 26.3 10.1
4 37.2 10.6 4 87.2 17.6
Acclimated under a
4 30.6 10.2
variable temperature
scheme
TABLE 2
WHARF ANIMALS
Respiration rates (ul O, consumedg/hi
lest temperatures
19.000
6.100
12.000
n x
nXS
n x
8
+ 30.3 5.4
4 43.4 2.7
5 98.1 23.5
Freshly collected
4 35.2 3.8
4 103.2 40.0
4 55.0 15.7
Acclimated at 6°0
5 84.7 20.7
5 40.3 9.2
Acclimated at 12°0
5 28.5 4.6
2 54.5 5.8
2 121.3 22.6
Acclimated at 19°0
2 39.0 9.7
Acclimated under a
4 115.3 30.4
3 51.5 22.3
4 34.3 12.2
variable temperature
sch
p. 19
Dodecaceria fewkesi.
Temperature and habitat effects in
Figure 2. Respiratory rate / temperature curves of wharf animals.
Respiratory rate is calculated as ul 0, consumed per, gram wet weight per
nour. Error bars were omitted for clearer comparison of curves.
+ Animals from the field
o Animals kept at 12°0 for two weeks
E Animals kept at 6 C for two weeks
• Animals kept at 20 C for two weeks
Animals cycled between 6 and 20°C for two weeks
p. 20
20
Temperature and habitat effects in Dodecaceris
D. Campbell







80
120
Temperature
ewkes

0
190
p. 2
Temperature and habitat effects in Dodecaceria fewkesi
p. 22
D. Campbell
able 3. Amount of pigment released by animals when exposed to air followed
by room temperature seawater.
No pigment
+ Trace of pigment
++ Pigment made a yellow solution and precipitated out as black granules
over a period of a few hours.
+++ Water was opaque black after a few hours.
—
Temperature and habitat effects in Dodecaceria fewkesi.
Amount of
Pigmert released
Acclimat ion
TIME
Temperature
Intertidal
Wharf
O
+++
2 weeks
60
+
12°
2 weeks
++
+ ++
2 weeks
20
+++
2 weeks
6°-20
—
p. 23
+
Temperature and habitat effects in Dodecaceria fewkesi.
D. Campbell
C
O
(O
0
X
8
O
O

IX
IX

O
L
—


O)

p.24
Temperature and habitat effects in Dodecaceria fewkesi.
D. Campbell
gure 3. Respiratory rate / temperature curves of animals collected
fresh from the field or maintained in running 12°C seawater. Error bars
were omitted for clearer comparison of curves.
+ Deep reef animals
• Wharf animals
Intertidal animals
o Wharf animals for which the rates were corrected for weight
E Intertidal animals for which the rates were corrected for weight
p. 25
O
20
1.5
1.C
6.0
Temperature and habitat effects in Dodecaceria fewkesi.
D. Campbell




12.0
Temperature (°)


19.0
p. 26
84
20
—



V
5

a
O+


0OD
O—
10 -
OT
-



.


O+
-

o
0
8
5
Oa

8



0
O+
V
8
O —

OC
90