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. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
2.6. Processing of samples Five polyps were scored for each sample. Individual polyps were dissected out from
the decalcified tissue while viewed under a stereo dissecting microscope after Oliver, 1979; Wallace, 1985. Each polyp was dissected to expose the eight mesenteries. Four
mesenteries contained strings of eggs and four mesenteries developed testes. For each polyp, the number and the size of the eggs were scored. Two measurements were taken
from each egg, a ‘‘length’’ and ‘‘width’’ measurement using a calibrated eyepiece micrometer in the dissecting microscope. The egg size was the mean of these two
measures. The egg size of the polyp was the mean of the individual egg sizes. ‘‘Egg total’’ was calculated by adding all the individual egg sizes or by multiplying the polyp
egg size by the polyp egg number.
Testes were counted for the testes number. The length and width of each testis was measured using a calibrated eyepiece micrometer. The length and width of each testis
were multiplied together and the sum of these calculations for each polyp was called the ‘‘testes total’’ for that polyp.
2.7. Statistical analyses The egg number, polyp egg size, egg total and testes total were analysed for Acropora
longicyathus and Acropora aspera transplants using orthogonal two way nested analyses of variance Underwood, 1981. The main factors were the presence or absence of
nitrogen and the presence or absence of phosphorus. For the nitrogen analyses, microatolls exposed to elevated nitrogen nitrogen only and nitrogen plus phosphorus
microatolls were compared with those which did not receive nitrogen controls and phosphorus only microatolls. For the phosphorus analyses, microatolls exposed to
phosphorus phosphorus only and nitrogen plus phosphorus microatolls were compared with those which did not receive phosphorus controls and nitrogen only. Microatolls
were nested within the nitrogen by phosphorus interaction. Heterogeneity of variance was tested using Cochran’s test.
The data for the colonies of Acropora aspera naturally occurring in the microatolls were analysed using two way orthogonal analyses of variance without the microatoll
nesting as these colonies were only present in nine of the twelve microatolls. Fecundities of transplanted colonies of Acropora longicyathus in each treatment were
compared with those of their parental colonies using one way analyses of variance.
3. Results
3.1. Acropora longicyathus transplants Elevated nutrients affected the polyp fecundity of Acropora longicyathus transplants
in the experimental microatolls. The nitrogen treatments nitrogen alone and nitrogen plus phosphorus tended to reduce the number and size of eggs per polyp and the testes
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
185
total Figs. 1–7. Phosphorus alone had a different effect reflected in the many significant nitrogen by phosphorus interactions found in the analyses of variance.
Phosphorus generally reduced the size of the eggs but often caused an increase in the number of eggs per polyp Tables 1–7. For this reason the results for the phosphorus
only corals will be described separately.
Fig. 1. The mean number of eggs present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from November 1993 to November 1994. Error bars are standard
errors.
186 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 2. The mean size of eggs mm present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from November 1993 to November 1994. Error bars are standard
errors.
3.2. Phosphorus only The mean number of eggs per polyp was elevated in the phosphorus only microatolls
compared with other treatments on most sampling dates towards the end of the gametogenic cycles. The transplants from the controls, nitrogen and nitrogen plus
phosphorus showed a reduction in the number of eggs per polyp present during the gametogenic cycle, so that the number of eggs per polyp present in February and May
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
187
Fig. 3. The mean egg total egg size3egg number present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from November 1993 to November 1994. Error bars are
standard errors.
was greater than the number in November Fig. 5. In contrast, the corals exposed to elevated phosphorus only retained almost all of the eggs present early in the cycle until
the spawning period. Early in the cycle there were no significant differences between egg numbers of the phosphorus only corals and the other treatments February 1995,
May 1995 Tables 4–5 but by August and November, when corals from the other treatments had reduced mean egg numbers per polyp, there were significantly more eggs
in the phosphorus corals than those in the other treatments November 1993, 1994, 1995, August 1995 Tables 1, 3, 6, 7; Figs. 1, 5.
188 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 4. The mean testes total present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from November 1993 to November 1995. Error bars are standard errors.
In contrast, phosphorus significantly reduced the size of the eggs in November 1993 and November 1994 Tables 1, 3; Fig. 2 with a mean egg size of 359 mm in November
1993 compared with 382 mm in the control colonies. Phosphorus alone significantly increased the egg total on some dates November 1993, 1994, 1995 Tables 1, 3, 7;
Figs. 3, 7. There was more testes material present in corals exposed to elevated phosphorus only compared with other treatments, and this was most pronounced in
November 1994 when the testes total for these corals was 2100 compared to 1339 in the controls. The testes total was significantly increased in the phosphorus only microatolls
in November 1994 and 1995 but not in November 1993 Tables 1, 3, 7; Fig. 4.
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
189
Fig. 5. The mean number of eggs present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from February 1995 to November 1995. Error bars are standard
errors.
3.3. Nitrogen The effects of the presence of elevated nitrogen on the fecundity of Acropora
longicyathus were less obvious but the direction of effect of both nitrogen and nitrogen
190 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 6. The mean size of eggs mm present in polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from February 1995 to November 1995. Error bars are standard
errors.
plus phosphorus treatments was the same. The mean number of eggs per polyp in the nitrogen treatments was reduced on some dates but not others. The egg number was
significantly reduced in corals exposed to nitrogen compared with those not exposed to nitrogen in November 1993 Table 1, Fig. 1 and June 1994 Table 2, Fig. 1. However,
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
191
Fig. 7. The mean egg total egg number3egg size of polyps of Acropora longicyathus transplants from the experimental microatolls at One Tree Reef from February 1995 to November 1995. Error bars are standard
errors.
by November 1994 the nitrogen only treatment colonies had resorbed fewer eggs than the control colonies resulting in a similar mean number of eggs per polyp among these
treatments.
192 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 1
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in November 1993 df
SS MS
F P
Egg number Nitrogen
1 575.93
575.93 16.04
,0.0001 Phosphorus
1 216.80
216.80 6.04
0.015 Nit. by phos.
1 122.28
122.28 3.41
0.066 Microatoll within N3P
8 1706.23
213.28 5.94
,0.0001 Total
284 10 197.73
35.91 C 50.3203, P 50.118
Egg size Nitrogen
1 0.00
0.00 0.01
0.910 Phosphorus
1 0.01
0.01 6.33
0.013 Nit. by phos.
1 0.01
0.01 12.71
,0.0001 Microatoll within N3P
8 0.03
0.00 4.05
,0.0001 Total
237 0.24
0.00 C 50.4406, P ,0.0001
Egg total Nitrogen
1 130 259.10
130 259.10 16.28
,0.0001 Phosphorus
1 30 023.99
30 023.99 3.75
0.054 Nit. by phos.
1 9935.05
9935.05 1.24
0.266 Microatoll within N3P
8 321 975.02
40 246.88 5.03
,0.0001 Total
284 2 272 226.05
8000.80 C 50.3156, P 50.153
Testes total Nitrogen
1 46 389 355.20
46389 355.27 50.73
,0.0001 Phosphorus
1 1 084 505.18
1 084 505.20 1.19
0.277 Nit. by phos.
1 901 420.09
901 420.10 8.64
0.004 Microatoll within N3P
8 55 761 090.93
6 970 136.40 7.62
,0.0001 Total
284 259 677 748.4
914 358.27 C 50.3148, P 50.160
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
Smaller eggs were found in the nitrogen treatments than in the non-nitrogen treatments and this effect was most pronounced in the corals exposed to nitrogen only
e.g. a mean egg size of 302 mm compared to 338 mm in controls in November 1995. Egg size was significantly reduced by elevated nitrogen compared to treatments without
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
193 Table 2
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in June 1994 df
SS MS
F P
Egg number Nitrogen
1 1.40
1.40 23.62
,0.0001 Phosphorus
1 0.34
0.34 5.68
0.018 Nit. by phos.
1 0.33
0.33 5.56
0.019 Microatoll within N3P
8 1.71
0.21 3.61
0.001 Total
284 16.80
0.06 C 50.4585, P ,0.0001
Egg size Nitrogen
1 0.16
0.16 0.21
0.644 Phosphorus
1 11.60
11.60 15.89
,0.0001 Nit. by phos.
1 1.93
1.93 2.64
0.106 Microatoll within N3P
8 17.20
2.15 2.95
0.004 Total
274 199.99
0.73 C 50.3125, P 50.190
Egg total Nitrogen
1 2.68
2.68 20.30
,0.0001 Phosphorus
1 1.55
1.55 11.75
0.001 Nit. by phos.
1 0.73
0.73 5.49
0.020 Microatoll within N3P
8 4.14
0.52 3.92
,0.0001 Total
284 37.51
0.13 C 50.3706, P 50.003
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
elevated nitrogen November 1993, 1994, 1995, May 1995, August 1995 Tables 1–7; Figs. 2, 7. Egg total was also reduced by the presence of elevated nitrogen in November
1993, June 1994, November 1994 and November 1995 Tables 1,2,3,7; Figs. 3, 7. Exposure to elevated nitrogen reduced the amount of testes material produced with the
nitrogen only corals having mean values of almost double those of the nitrogen plus phosphorus corals in November 1993. The testes total was significantly reduced by
exposure to nitrogen in November 1993 and 1995 Tables 1, 7. In November 1995 the nitrogen and nitrogen plus phosphorus treatments had mean testes total values approxi-
mately two thirds those of the control colonies.
3.4. Acropora longicyathus: comparison of transplants and parental colonies Comparisons of measures of fecundity between transplanted corals and their parental
194 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 3
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in November 1994 df
SS MS
F P
Egg number Nitrogen
1 546.86
546.86 15.38
,0.0001 Phosphorus
1 158.97
158.97 4.47
0.035 Nit. by phos.
1 616.44
616.44 17.34
,0.0001 Microatoll within N3P
8 2250.17
281.27 7.91
,0.0001 Total
275 9778.86
35.56 C 50.3226, P 50.109
Egg size Nitrogen
1 5.46
5.46 4.34
0.038 Phosphorus
1 5.71
5.71 4.53
0.034 Nit. by phos.
1 0.11
0.11 0.09
0.765 Microatoll within N3P
8 18.39
2.30 1.83
0.073 Total
254 319.74
1.26 C 51.8997, P 50.128
Egg total Nitrogen
1 108 918.68
108 918.32 17.12
,0.0001 Phosphorus
1 23 744.00
23 744.00 3.73
0.054 Nit. by phos.
1 136 386.88
136 386.88 21.44
,0.0001 Microatoll within N3P
8 439 416.86
54 927.11 8.63
,0.0001 Total
275 1 749 362.94
6361.32 C 50.3105, P 50.211
Testes total Nitrogen
1 12 970 522.44
12 970 522.44 19.23
,0.0001 Phosphorus
1 501 382.34
501 382.34 0.74
0.389 Nit. by phos.
1 21 343 691.18
21 343 691.18 31.65
,0.0001 Microatoll within N3P
8 61 677 283.07
7 709 660.40 11.43
,0.0001 Total
275 185 460 785.7
74 402.86 C 50.2939, P 50.463
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Testes volume data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
colonies provide information about the effects of transplantation to shallower water and the effects of nutrients. Transplanted corals tended to produce smaller eggs than their
parental colonies Fig. 9, but generally the differences between transplanted corals and their parents were most pronounced when there was also a difference between the
transplant treatment and the other treatments. For example, if there were more eggs in
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
195 Table 4
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in February 1995 df
SS MS
F P
Egg number Nitrogen
1 0.00
0.00 0.01
0.943 Phosphorus
1 0.03
0.03 1.51
0.222 Nit. by Phos
1 0.20
0.20 11.36
0.001 Microatoll within N3P
8 0.25
0.03 1.83
0.080 Total
101 1.74
0.02 C 50.4351, P 50.008
Egg size Nitrogen
1 0.00
0.00 0.11
0.741 Phosphorus
1 0.00
0.00 0.26
0.614 Nit. by phos.
1 0.01
0.01 2.91
0.091 Microatoll within N3P
8 0.14
0.02 3.89
,0.0001 Total
106 0.46
0.00 C 50.4121, P 50.017
Egg total Nitrogen
1 0.00
0.00 0.10
0.747 Phosphorus
1 0.02
0.02 0.98
0.324 Nit. by phos.
1 0.17
0.17 8.03
0.006 Microatoll within N3P
8 0.52
0.06 3.13
0.003 Total
101 2.09
0.02 C 50.4619, P 50.002
a
Two way orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus. Data were logx 11 transformed due to heterogeneity of variances. C
denotes the Cochran’s test value.
the colonies exposed to phosphorus only on a certain date, there would be more eggs in those transplants than their parental colonies on that date Figs. 8–11.
There were no significant differences between the number of eggs per polyp in the control colonies and their parental colonies between November 1993 and 1995 ANOVA
1993: df5139, F 50.5021, P 50.4798. 1994: df5130, F 53.6591, P 50.0580. 1995: df5145, F 50.5913, P 50.4432 Fig. 8. Although there were significantly fewer eggs
per polyp in the nitrogen transplants than the other treatments in November 1993, there was no significant difference between the number of eggs in these corals and their
parental colonies on this date or in November 1994 ANOVA 1993: df5149, F 51.2437, P 50.2666. 1994: df5140, F 50.0207, P 50.8857 In contrast, there were significantly
more eggs per polyp in the nitrogen only transplants than their parents in November 1995 ANOVA df5149, F 54.2093, P 50.0420.
Reflecting the difference between nutrient treatments, there were significantly more eggs in the phosphorus only transplants than their parental colonies in 1993, 1994 and
196 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 5
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in May 1995 df
SS MS
F P
Egg number Nitrogen
1 0.01
0.01 1.00
0.320 Phosphorus
1 0.01
0.01 0.65
0.423 Nit. by phos.
1 0.00
0.00 0.33
0.566 Microatoll within N3P
7 0.77
0.11 10.53
,0.0001 Total
164 1.70
0.01 C 50.3999, P ,0.0001
Egg size Nitrogen
1 0.00
0.00 0.46
0.498 Phosphorus
1 0.00
0.00 0.47
0.494 Nit. by phos.
1 0.00
0.00 0.68
0.410 Microatoll within N3P
8 0.16
0.02 3.75
0.001 Total
164 0.99
0.01 C 50.4504, P ,0.0001
Egg total Nitrogen
1 0.00
0.00 0.13
0.720 Phosphorus
1 0.02
0.02 0.91
0.340 Nit. by phos.
1 0.00
0.00 0.02
0.876 Microatoll within N3P
7 1.63
0.23 10.42
,0.0001 Total
164 3.67
0.02 C 50.4449, P ,0.0001
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
1995 e.g. ANOVA 1993: df5150, F 519.4111, P ,0.0001 and fewer eggs in the nitrogen plus phosphorus corals than their parental colonies in 1993 and 1994 e.g.
ANOVA 1993: df5149, F 57.4951, P 50.0069. The size of the eggs of transplanted colonies was generally significantly smaller than
those of the parental colonies Fig. 9. The only exceptions were the control corals in November 1993 ANOVA df5112, F 52.7986, P 50.0972 and November 1995
ANOVA df5146, F 52.0885, P 50.1506 and the nitrogen plus phosphorus corals in November 1993 ANOVA df5122, F 52.2947, P 50.1324.
The egg total of the parental colonies generally mirrored the transplants except where there was a difference due to treatment e.g. ANOVA 1993 phosphorus: df5150,
F 513.9679, P 50.0003; ANOVA 1994 nitrogen plus phosphorus: df5149, F 515.1689, P 50.0001.
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
197 Table 6
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in August 1995 df
SS MS
F P
Egg number Nitrogen
1 72.76
72.76 3.11
0.081 Phosphorus
1 163.71
163.71 7.00
0.009 Nit. by phos.
1 533.68
533.68 22.81
,0.0001 Microatoll within N3P
8 839.75
104.97 4.49
,0.0001 Total
164 1.70
0.01 C 50.3613, P 50.136
Egg size Nitrogen
1 0.00
0.00 1.81
0.182 Phosphorus
1 0.02
0.02 8.77
0.004 Nit. by phos.
1 0.00
0.00 0.01
0.938 Microatoll within N3P
8 0.08
0.01 3.69
0.001 Total
104 0.29
0.00 C 50.4228, P 50.012
Egg total Nitrogen
1 3 016 057.10
3 016 057.10 4.54
0.035 Phosphorus
1 7 550 206.50
7 550 206.50 11.36
0.001 Nit. by phos.
1 12 322 168.32
12 322 168.32 18.55
,0.0001 Microatoll within N3P
8 22 552 044.67
2 819 005.60 4.24
,0.0001 Total
104 69 092 659.79
664 352.50 C 50.3612, P 50.136
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction.
A regular pattern was not obvious for the testes total of the transplants and parental colonies. In November 1993, only the nitrogen plus phosphorus corals had a sig-
nificantly lower testes total than that of the parental colonies ANOVA df5149, F 513.3297, P 50.0004. In November 1994 and 1995 the phosphorus transplant
colonies had significantly greater testes totals than those of the parental colonies and this reflects the treatment differences Fig. 11 ANOVA 1994: df5147, F 511.4736,
P 50.0009. 1995: df5144, F 556.53, P ,0.0001. The control transplant colonies had smaller testes than their parental colonies in November 1994 ANOVA df5130,
F 54.5246, P 50.0353 but larger testes in November 1995 ANOVA df5145, F 5 6.8142, P 50.0100.
3.5. Acropora aspera transplants There were some Acropora aspera transplants that had no eggs or testes in their
198 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 7
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora longicyathus transplants in the experimental microatolls at One Tree Reef in November 1995 df
SS MS
F P
Egg number Nitrogen
1 659.06
659.06 20.52
,0.0001 Phosphorus
1 740.17
740.17 23.05
,0.0001 Nit. by phos.
1 614.12
614.12 19.12
,0.0001 Microatoll within N3P
8 1235.68
154.46 4.81
,0.0001 Total
288 9267.30
32.12 C 50.3107, P 50.214
Egg size Nitrogen
1 92.36
92.36 9.37
0.002 Phosphorus
1 33.37
33.37 3.39
0.067 Nit. by phos.
1 6.62
6.62 0.67
0.413 Microatoll within N3P
8 387.90
48.49 4.92
,0.0001 Total
288 2837.63
9.85 C 50.3143, P 50.177
Egg total Nitrogen
1 1.99
1.99 7.61
0.006 Phosphorus
1 2.92
2.92 11.16
0.001 Nit. by phos.
1 0.35
0.35 1.35
0.246 Microatoll within N3P
8 9.50
1.19 4.54
,0.0001 Total
288 75.29
0.26 C 50.3741, P 50.003
Testes total Nitrogen
1 76 001 109.80
76 001 110.00 68.72
,0.0001 Phosphorus
1 5 824 819.61
5 824 819.61 5.27
0.022 Nit. by phos.
1 10 137 923.17
10 137 923.00 9.17
0.003 Microatoll within N3P
8 78 731 422.54
9 841 427.86 8.90
,0.0001 Total
288 318 508 158.3
1 105 931.10 C 50.2924, P 50.526
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
sample branches. This was due to colonies having either no gametes in the particular branch which was sampled or having no gametes in the entire colony. Due to this lack of
gametes in some of the November 1993 and particularly 1994 samples, the sample sizes were smaller than for the other dates. The mean number of eggs per polyp in the A
. aspera transplants was considerably lower than those in the Acropora longicyathus
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
199
Fig. 8. The number of eggs present in the colonies of Acropora longicyathus transplanted to the experimental microatolls at One Tree Reef. These are represented by the blank bars. The shaded bars represent the number
of eggs present in the parental colonies of the transplants which have remained in the lagoon at One Tree Reef. Error bars are standard errors.
colonies with the November 1993 treatment means ranging from 6.99 to 8.40 eggs per polyp in A
. aspera compared with up to 20 eggs per polyp in A. longicyathus. The mean number of eggs present was particularly low in November 1994 for A
. aspera with means of 0.4 to 5 per polyp Fig. 12. Eggs measured in the November 1993 samples
200 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 9. The size of eggs mm present in the colonies of Acropora longicyathus transplanted to the experimental microatolls at One Tree Reef. These are represented by the blank bars. The shaded bars represent
the number of eggs present in the parental colonies of the transplants which have remained in the lagoon at One Tree Reef. Error bars are standard errors.
were bigger than those from 1994 or 1995 Fig. 13. The mean egg size for all A . aspera
transplants for November 1993 was 425 mm compared with 321 mm in November 1995. The trends found in the fecundity of Acropora longicyathus colonies were also
apparent for the A . aspera colonies Figs. 12–15. In November 1993, the mean egg
number per polyp was higher in the nitrogen plus phosphorus microatolls than in the other treatments but this pattern was not found on other sampling dates. In contrast,
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
201
Fig. 10. The egg total egg size3egg number present in the colonies of Acropora longicyathus transplanted to the experimental microatolls at One Tree Reef. These are represented by the blank bars. The shaded bars
represent the number of eggs present in the parental colonies of the transplants which have remained in the lagoon at One Tree Reef. Error bars are standard errors.
significantly fewer eggs per polyp were found in the nitrogen plus phosphorus treatment than in other treatments in November 1994 Table 8, Fig. 12. In October 1994,
November 1994 and November 1995 there were significantly more eggs per polyp in the phosphorus alone treatment than in the other treatments Fig. 12.
Eggs were significantly smaller in the phosphorus treatments phosphorus alone and nitrogen plus phosphorus compared with the non-phosphorus treatments in October
1994 Table 9, Fig. 13. In November 1995 the eggs were smaller in the nitrogen than in
202 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 11. The testes total present in the colonies of Acropora longicyathus transplanted to the experimental microatolls at One Tree Reef. These are represented by the blank bars. The shaded bars represent the number
of eggs present in the parental colonies of the transplants which have remained in the lagoon at One Tree Reef. Error bars are standard errors.
the non-nitrogen treatments and in the phosphorus than in the non-phosphorus treatments Table 9, Fig. 13. In November 1994 the eggs were larger in the nitrogen plus
phosphorus treatments than the other treatments. Egg total was much larger in November 1993 than on the other sampling dates. The
egg total in the nitrogen plus phosphorus treatment was significantly reduced in November 1994 and 1995 but was elevated in November 1993. Egg total was elevated in
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
203
Fig. 12. The mean number of eggs present in polyps from colonies of Acropora aspera which were transplanted into the experimental microatolls at One Tree Reef, during the period from November 1993 to
November 1995. Error bars are standard errors.
the phosphorus only microatolls compared with the other treatments in October 1994, November 1994 and November 1995 Tables 8–10; Fig. 14.
Testes totals varied a great deal with both date and treatment. The testes total was considerably larger in November 1993 than on other sampling dates with the mean for
204 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 13. The mean size of eggs mm present in polyps from colonies of Acropora aspera which were transplanted into the experimental microatolls at One Tree Reef, during the period from November 1993 to
November 1995. Error bars are standard errors.
all the transplants in November 1993 four times greater than that for November 1994. Testes totals were particularly variable in November 1994 with treatment mean for the
nitrogen plus phosphorus microatolls less than one sixth that of the phosphorus only microatolls. There were greater testes totals present in the phosphorus only treatment
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
205
Fig. 14. The mean egg total egg number3egg size present in polyps from colonies of Acropora aspera which were transplanted into the experimental microatolls at One Tree Reef, during the period from November
1993 to November 1995. Error bars are standard errors.
compared to other treatments on October 1994, November 1994 and November 1995 Tables 8–10; Fig. 15. The testes totals were dramatically reduced in the nitrogen plus
phosphorus microatolls in October and November 1994 and November and in the nitrogen only treatment in November 1995.
206 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 15. The mean testes total present in polyps from colonies of Acropora aspera which were transplanted into the experimental microatolls at One Tree Reef, during the period from November 1993 to November
1995. Error bars are standard errors.
3.6. Acropora aspera occurring naturally in the microatolls The Acropora aspera growing naturally in the microatolls had a higher fecundity than
the A . aspera transplants. The mean number of eggs per polyp in the colonies of
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
207 Table 8
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora aspera transplants in the experimental microatolls at One Tree Reef in November 1993 df
SS MS
F P
Egg number Nitrogen
1 0.09
0.09 0.02
0.885 Phosphorus
1 15.01
15.01 3.45
0.065 Nit. by phos.
1 29.85
29.85 6.86
0.010 Microatoll within N3P
8 79.80
9.98 2.29
0.024 Total
156 678.32
4.35 C 50.3127, P 50.395
Egg size Nitrogen
1 0.00
0.00 0.75
0.386 Phosphorus
1 0.00
0.00 0.88
0.351 Nit. by phos.
1 0.00
0.00 1.43
0.233 Microatoll within N3P
8 0.01
0.00 1.56
0.139 Total
178 0.17
0.00 C 50.4118, P ,0.0001
Egg total Nitrogen
1 107.01
107.01 0.10
0.748 Phosphorus
1 3181.75
3181.75 3.07
0.081 Nit. by phos.
1 6596.57
6596.57 6.37
0.013 Microatoll within N3P
8 18 964.78
2370.60 2.29
0.024 Total
156 161 438.32
1034.86 C 50.3296, P 50.285
Testes total Nitrogen
1 0.41
0.43 1.35
0.247 Phosphorus
1 0.38
0.38 1.23
0.269 Nit. by phos.
1 0.48
0.48 1.57
0.212 Microatoll within N3P
8 4.06
0.51 1.67
0.112 Total
135 41.11
0.30 C 50.36475, P 50.019
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
Acropora aspera occurring naturally in the microatolls was greater in the controls in November 1994 10.9 compared with 1.77 for the transplants and in all treatments in
November 1995 than in the A . aspera transplants November 1995 treatment means for
egg number per polyp ranged from 12.90 to 15.67 for naturally growing A . aspera
compared with 5.38–8.30 for the transplanted colonies.
208 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 9
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora aspera transplants in the experimental microatolls at One Tree Reef in October 1994 df
SS MS
F P
Egg number Nitrogen
1 1.54
1.54 12.95
,0.0001 Phosphorus
1 0.60
0.60 5.02
0.026 Nit. by phos.
1 3.55
3.55 29.82
,0.0001 Microatoll within N3P
8 6.96
0.87 7.30
,0.0001 Total
282 33.59
0.12 C 50.4313, P ,0.0001
Egg size Nitrogen
1 0.00
0.00 0.91
0.343 Phosphorus
1 0.01
0.01 4.66
0.034 Nit. by phos.
1 0.00
0.00 0.38
0.541 Microatoll within N3P
7 0.05
0.01 5.20
,0.0001 Total
85 0.11
0.00 C 50.4456, P 50.011
Egg total Nitrogen
1 6.66
6.66 12.08
0.001 Phosphorus
1 2.04
2.04 3.69
0.056 Nit. by phos.
1 15.04
15.04 27.29
,0.0001 Microatoll within N3P
8 31.36
3.92 7.11
,0.0001 Total
282 155.45
0.55 C 50.4267, P ,0.0001
Testes total Nitrogen
1 18.93
18.93 15.72
,0.0001 Phosphorus
1 2.74
2.74 2.28
0.132 Nit. by phos.
1 41.40
41.40 34.38
,0.0001 Microatoll within N3P
8 75.06
9.38 7.79
,0.0001 Total
282 339.53
1.20 C 50.0.4375, P ,0.0001
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
In November 1994, the number of eggs per polyp was significantly reduced in both the nitrogen treatments compared to the non-nitrogen treatments and in the phosphorus
treatments compared with the non-phosphorus treatments, with the least number of eggs per polyp in the nitrogen plus phosphorus microatolls 2.4 compared with 10.9 for the
controls Tables 11 and 12; Fig. 16. In November 1995, there were significantly more eggs per polyp in the phosphorus microatolls than in the other treatments, and
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
209 Table 10
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total
a
of the Acropora aspera transplants in the experimental microatolls at One Tree Reef in November 1994 df
SS MS
F P
Egg number Nitrogen
1 1.68
1.68 15.49
,0.0001 Phosphorus
1 0.25
0.25 2.29
0.132 Nit. by phos.
1 7.13
7.13 65.77
,0.0001 Microatoll within N3P
7 5.37
0.77 7.07
,0.0001 Total
205 22.22
0.11 C 50.4044, P 50.002
Egg size Nitrogen
1 0.02
0.02 5.38
0.023 Phosphorus
1 0.03
0.03 10.74
0.002 Nit. by phos.
1 0.02
0.02 8.33
0.005 Microatoll within N3P
4 0.03
0.01 3.05
0.021 Total
84 0.24
0.00 C 50.4315, P 50.022
Egg total Nitrogen
1 7.44
7.44 13.17
,0.0001 Phosphorus
1 0.93
0.93 1.65
,0.0001 Nit. by phos.
1 35.91
35.91 63.53
,0.0001 Microatoll within N3P
7 27.67
3.95 6.99
,0.0001 Total
205 115.88
0.57 C 50.3802, P 50.008
Testes total Nitrogen
1 12.86
12.86 9.55
0.002 Phosphorus
1 1.25
1.25 0.93
0.336 Nit. by phos.
1 78.66
78.66 58.39
,0.0001 Microatoll within N3P
7 59.86
8.55 6.35
,0.0001 Total
205 276.14
1.35 C 50.3898, P 50.004
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus with microatoll number nested within the treatment
interaction. Data were logx 11 transformed due to heterogeneity of variances. C denotes the Cochran’s test value.
significantly fewer eggs in the nitrogen treatments nitrogen and nitrogen plus phosphor- us than in the non-nitrogen treatments.
The mean size of eggs in the polyps of the A . aspera colonies occurring naturally in
the microatolls was similar to that in the A . aspera transplants. In November 1994, the
eggs were smaller in the control microatolls than those of the other treatments Table 11,
210 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221 Table 11
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total of the Acropora aspera growing naturally in the experimental microatolls at One Tree Reef in November
a
1994 df
SS MS
F P
Egg number Nitrogen
1 412.09
412.09 20.81
,0.0001 Phosphorus
1 111.57
111.57 5.64
0.021 Nit. by phos.
1 3.18
3.18 0.16
0.690 Total
53 1049.34
19.80 C 50.4244, P 50.112
Egg size Nitrogen
1 4.60
4.60 3.19
0.085 Phosphorus
1 27.42
27.42 18.98
,0.0001 Nit. by phos.
1 3.13
3.13 2.17
0.152 Total
28 40.44
1.44 C 50.3345, P 50.134
Egg total Nitrogen
1 69 194.20
69194.20 16.02
,0.0001 Phosphorus
1 9925.28
9925.28 2.30
0.136 Nit. by phos.
1 157.40
157.40 0.04
0.849 Total
53 228 984.04
4320.45 C 50.4314, P 50.095
Testes total Nitrogen
1 25.65
25.65 15.87
,0.0001 Phosphorus
1 9.46
9.46 5.85
0.019 Nit. by phos.
1 0.26
0.26 0.16
0.687 Total
51 82.43
1.62 C 50.5324, P 50.006
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus. Data were logx 11 transformed due to heterogeneity of
variances. C denotes the Cochran’s test value.
Fig. 17. In contrast, in November 1995 the eggs were smaller in all nutrient treatments compared with the controls Table 12, Fig. 17.
The mean egg total was greater in the Acropora aspera occurring naturally in the microatolls than in A
. aspera transplants. In November 1994 the egg total was significantly smaller in the nitrogen treatments than the non-nitrogen treatments. In
November 1995 the egg total in the nitrogen only microatolls was smaller than all other treatments Tables 11 and 12; Fig. 18. The testes total was greater in the A
. aspera occurring naturally in the control microatolls than the A
. aspera transplants in the
S . Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
211 Table 12
Comparison of the number of eggs, the size of eggs, the egg total egg number3egg size and the testes total of the Acropora aspera growing naturally in the experimental microatolls at One Tree Reef in November
a
1995 df
SS MS
F P
Egg number Nitrogen
1 4.14
4.14 60.90
,0.0001 Phosphorus
1 2.60
2.60 38.34
,0.0001 Nit. by phos.
1 2.01
2.01 29.61
,0.0001 Total
81 5.50
0.07 C 50.4787, P 50.005
Egg size Nitrogen
1 0.00
0.00 0.73
0.396 Phosphorus
1 0.00
0.00 0.01
0.935 Nit. by phos.
1 0.00
0.00 0.30
0.584 Total
61 0.09
0.00 C 50.4856, P 50.0.014
Egg total Nitrogen
1 14.10
14.10 59.24
,0.0001 Phosphorus
1 11.23
11.23 47.17
,0.0001 Nit by phos
1 9.95
9.95 41.78
,0.0001 Total
81 19.28
0.24 C 50.4796, P 50.005
Testes total Nitrogen
1 5 226 820.4
5 226 820.7 36.05
,0.0001 Phosphorus
1 2 624 680.2
2 624 680.2 18.10
,0.0001 Nit. by phos.
1 2 978 954.2
2 978 954.2 20.55
,0.0001 Total
81 11 744 574.2
144 994.7 C 50.5324, P 50.006
a
Two way nested orthogonal analyses of variance were used. Treatments were presence or absence of nitrogen and presence or absence of phosphorus. Data were logx 11 transformed due to heterogeneity of
variances. C denotes the Cochran’s test value.
control corals in November 1994 by a factor of more than five. In November 1995, the testes total was greater in the naturally occurring A
. aspera in all treatments compared with the transplants. In November 1994, the testes total was significantly reduced in the
nitrogen compared with the non-nitrogen treatments and in the phosphorus treatments compared with the non-phosphorus treatments. The smallest testes total occurred in the
nitrogen plus phosphorus microatolls and the mean testes total for this treatment was less than one fifth that of the control treatment Tables 11 and 12, Fig. 19. Results are
summarised in Table 13.
212 S
. Ward, P. Harrison J. Exp. Mar. Biol. Ecol. 246 2000 179 –221
Fig. 16. The mean number of eggs present in the polyps of colonies of Acropora aspera occurring naturally in the experimental microatolls. Error bars are standard errors.
4. Discussion
