Figure 1.
A. Map of the Caribbean with the location of Curaçao indicated. B. Map of Curaçao, Netherlands Antilles. Filled triangle and circle indicate location of study sites Sea Aquarium reef and Barracuda Point reef, respectively.
Figure 2.
Erect branching sponge species and experimental substratum treatments.
A. Aplysina cauliformis. B. Aplysina sp. C. Niphates erecta. D. Coral rubble alone. E. Coral rubble with sponge fragments inserted into pile. F. Concrete bound coral rubble. G. Concrete bound concrete “rubble”.
Table 1.
Number of treatment clusters by site and depth.
Table 2.
Number of sponge-rubble piles by site seeded with fragments of each sponge species.
Figure 3.
Influence of treatment and water depth on rubble pile height over time.
Conditional boxplots of rubble pile height for Sea Aquarium and Barracuda point. A and C. Rubble pile height conditional on water depth at Sea Aquarium and Barracuda Point, respectively. B and D. Rubble pile height conditional on treatment at Sea Aquarium and Barracuda Point, respectively. Thick solid and broken bars inside boxes indicate median and mean height, respectively. Letters above boxes indicate significant differences (P<0.05) between factor levels based on pairwise comparison of means with Bonferroni correction.
Figure 4.
Sponge fragments stabilizing rubble in piles three months post deployment at Sea Aquarium.
Sponge fragments inserted into piles grew and adhered to adjacent pieces of rubble in less than three months. A and B. Aplysina cauliformis stabilizing sections of rubble piles. C. Coral rubble stabilization by Aplysina sp.
Figure 5.
Consolidation of rubble piles with and without sponges by carbonate secreting organisms.
A. Sea Aquarium. B. Barracuda point. Number of unconsolidated piles is represented by light grey bars and consolidated piles by black bars. Asterisks above bars indicate significant differences (* p<0.05, ** p<0.01) in the proportion of consolidated vs. unconsolidated piles between treatments within the same site, at the same time period, by the G-test of independence. Statistical results from each comparison are provided in Table S3.
Table 3.
Percent of coral rubble piles remaining over time per treatment by site.
Figure 6.
Number of coral recruits at each site, during each survey, by treatment.
A. Sea Aquarium. B. Barracuda point. For Sea Aquarium (A): open, light gray, dark gray and black bars indicate the number of coral recruits at months 12, 24, 36, and 48, respectively. For Barracuda Point (B): open, light gray, dark gray and black bars indicate the number of coral recruits at months 12, 21, 33, and 45, respectively. Letters above black bars (months 48 and 45 for Sea Aquarium and Barracuda Point, respectively), indicate significant differences (P<0.05) among treatments within each site in the number of coral recruits based on pairwise comparison with Bonferroni correction. Within each site, bars that share the same letter are not significantly different (P>0.05) from one another.
Table 4.
Number and identity of coral recruits per treatment 48 and 45 months post deployment at Sea Aquarium and Barracuda Point, respectively.
Table 5.
Number of days taken by sponge fragments to attach to coral rubble.
Table 6.
Annual percent change in volume of sponge individuals that increased in size.
Figure 7.
Cumulative replacement of excised tissue (PVR) by sponges.
A. Cumulative mean percent of tissue excised that was replaced at each 3 month period, in terms of volume, by all sponges surviving for 15 months: Aplysina cauliformis (N = 29), Aplysina sp. (N = 34), Niphates erecta (N = 39). Standard error bars are shown. Aplysina cauliformis and Aplysina sp. replaced tissue significantly (P<0.05) more rapidly than N. erecta (determined by pairwise comparison of means with Bonferroni correction) (See Table S4).