The overgrowing, boring sponge Cliona viridis was studied on the Southwest coast of Grand Cayman Island, British West Indies. The surface area covered by the sponge was estimated using transect and quadrat surveys. Between 1 and 8 m depth, the average substrate coverage was 5%. Smaller sponge colonies were usually subcircular and larger colonies more dendritic. This change in shape may aid in exploiting new substrate. The sponge removes between 13.9% and 32.2% of the substrate as it expands laterally and produces an average erosional rate of 0.6 mm yr ⁻¹. Average sediment production rate is 1 kg m ⁻² yr ⁻¹. The chips produced by the sponge comprised only 0.0122% to 1.250% of the bottom sediments. Presumably, the majority of the sponge-produced sediments were transported out by water currents. / Thesis / Bachelor of Science (BSc)

Production of fine sediments in reef environments is a poorly understood but probably significant process. On the Great Barrier Reef, Cliona viridis is locally abundant. The sponge has been found from Lizard Island in the north, down to the southern part of the Central Region, and it is likely even more widespread. Although on individual reefs the sponge may occur almost anywhere, it is most abundant on lagoon path reefs ("bommies" in Australian), where it overgrows the substrate and bores to a constant depth of about 1.3cm. Sponge infestation reaches a maximum at a depth of 4 m covering almost 8% of the vertical sides of bommies. It is frequently the dominant benthic organism. Serial underwater photography demonstrates that colonies can expand laterally at a rate of about 1 cm yr⁻¹ removing approximately 40% of the substrate. This species is a major producer of fine sediment on the Great Barrier Reef. / Thesis / Master of Science (MS)

Sponges contribute to large number of functions in coral reef ecosystems. Among these, bioerosion is perhaps one of the most widely studied, largely due to the important contribution of excavating sponges to the carbonate budget on coral reefs (up to 95 % of the total internal bioerosion). Despite our current knowledge, much of the literature is centred on individual-based observations, and little is known about their ecological role and interactions with other reef taxa in complex coral reef systems. The aim of this thesis was to quantify the ecological interactions of bioeroding sponges with major reef taxa by scaling up individual observations to population and ecosystem-based approaches. A cosmopolitan, abundant and highly competitive bioeroding sponge from Glover’s Atoll, Belize (Cliona tenuis) was used as model species. Monitoring of C. tenuis populations throughout 2009 indicated a trade-off between reproduction and growth, with the highest growth rates (31.4 ± 5.6 mm.y–1) occurring in summer, and a peak in reproductive output during winter. Populations typically show strong left-skewed size frequency distributions, mostly represented by juvenile-size individuals (46%), suggesting that regulating mechanisms (e.g. competition and predation) may be acting in constraining the transition of juveniles to adult sizes. Long-term in situ manipulations showed no effect of predation, yet competition with macroalgae significantly reduced the size of the sponge by 38% ± 11% (SE). While C. tenuis exhibit high growth and recruitment rates that could theoretically result in rapid population growth, the likelihood of sponges forming an alternative stable state as reefs sustain greater levels of disturbance is unclear. An analytical modelling approach of the interplay between macroalgae, coral and sponge was used to explore the likelihood of alternate stable states. The results show that irrespective of successful sponge invasion, inclusion of this third antagonist (in the interplay between coral and macroalgae) can qualitatively affect the likelihood of alternative stable state. The model exhibits emergent properties suggestive of intransitivity between the three competing taxa. Despite the potential of C. tenuis to benefit from disturbance, there are few cases in the literature reporting increases in bioeroding sponge abundance followed disturbance. Therefore, regulating mechanisms such as competition with other taxa, recruitment limitation or mortality are expected to exert demographic control on the populations of bioeroding sponges when space limitation is relaxed due to coral mortality. To determine processes regulating sponge populations, an individual-based spatial modelling approach was used to simulate the population dynamics of C. tenuis in a dynamic ecosystem environment. Using an orthogonal hypothesis testing approach, it was found that competition, and to a lesser extend partial mortality of the sponge tissue, largely regulate the population structure of C. tenuis. While reductions in coral cover may temporarily favour the rapid colonization by sponges, the competitive superiority of macroalgae may steal the opportunity from the opportunists.

In 2001, the Coral Reef Evaluation and Monitoring Program (CREMP) began monitoring the abundance and area covered by three clionid sponges (Cliona delitrix, C. lampa, and C. caribbaea). Subsequently, monitoring has been conducted annually at all 40 CREMP sites throughout the Florida Keys National Marine Sanctuary (FKNMS) and the Dry Tortugas. Between 2001 and 2002, mean clionid area decreased significantly from 7.6 cm2/m2 to 4.6 cm2/m2 (Wilcoxon; p= 0.035). Between 2002 and 2003, the decline to 4.5 cm2/m2 was not significant. Approximately 80% of all clionid colonies recorded at the CREMP stations covered less than 50 cm2. Among all recorded stony coral species, Montastraea annularis, M. cavernosa, and Siderastrea siderea were the most frequently and extensively invaded by clionid colonies. However, the vast majority of clionid colonies occurred in substrata not associated with a live coral colony. The mean percent cover for the four coral species identified to be most susceptible to clionid invasion had the greatest decline in the Dry Tortugas deep stations between 2001 and 2003. At Lower Keys patch-reef stations, mean percent cover showed a small, steady decrease, while at Upper Keys patch-reef stations, a small steady increase occurred. Fifteen water-quality parameters collected by the Water Quality Monitoring Network (WQMN) were analyzed to determine if clionid distributions correlated with water quality. When patch-reef sites were analyzed as a subset of sites, clionid area and abundance correlated strongly ( 0.65) with water-quality parameters that indicated higher nutrient flux and food resources. However, the correlation was weak when all 39 CREMP sites were considered ( 0.10). Clionid sponges are well known to be aggressive and successful bioeroders on coral reefs.

Made available in DSpace on 2014-12-17T14:13:23Z (GMT). No. of bitstreams: 1 AlexandreFSQ.pdf: 1970606 bytes, checksum: 5b6e9381595f936a1ed9bffd4f4fef7a (MD5) Previous issue date: 2008-05-12 / A galactose and sucrose specific lectin from the marine sponge Cliona varians named CvL was purified by acetone fractionation followed by Sepharose CL 4B affinity chromatography. Models of leukocyte migration in vivo were used to study the inflammatory activity of CvL through of mouse paw oedema and peritonitis. Effect of CvL on peritoneal macrophage activation was analyzed. Effects of corticoids and NSAIDS drugs were also evaluated on peritonitis stimulated by CvL. Results showed that mouse hind-paw oedema induced by sub plantar injections of CvL was dependent dose until 50?g/paw. This CvL dose when administered into mouse peritoneal cavities induced maxima cell migration (9283 cells/?L) at 24 hours after injection. This effect was preferentially inhibited by incubation of CvL with the carbohydrates D-galactose followed by sucrose. Pre-treatment of mice with 3% thioglycolate increases the peritoneal macrophage population 2.3 times, and enhanced the neutrophil migration after 24h CvL injection (75.8%, p<0.001) and no significant effect was observed in presence of fMLP. Finally, Pre-treatment of mice with dexamethason (cytokine antagonist) decreased 65.6%, (p<0.001), with diclofenac (non-selective NSAID) decreased 34.5%, (p<0.001) and Celecoxib (selective NSAID) had no effect on leukocyte migration after submission at peritonitis stimulated by CvL, respectively. Summarizing, data suggest that CvL shows pro-inflammatory activity, inducing neutrophil migration probably by pathway on resident macrophage activation and on chemotaxis mediated by cytokines / A lectina denominada CvL, com especificidade para D-galactose e sacarose foi purificada da esponja marinha Cliona varians atrav?s de fracionamento com acetona seguido por cromatografia de afinidade em Sepharose CL 4B. No presente trabalho, foi estudada a atividade inflamat?ria de CvL in vivo atrav?s dos modelos de edema de pata e migra??o de leuc?citos em peritonite induzida em camundongos. Foram analisados os efeitos de carboidratos na inibi??o da peritonite, o efeito da lectina na ativa??o de macr?fagos e o efeito de antiinflamat?rios no modelo de peritonite provocada pela CvL. Os resultados mostraram que o edema de pata induzido pela CvL foi dose dependente at? 50 ?g/pata. Essa mesma dose quando administrada na cavidade peritoneal, foi capaz de induzir migra??o celular (9.283 c?lulas/?L) com pico em 24 horas ap?s a administra??o. Este efeito foi inibido quando a CvL foi previamente incubada com os carboidratos D-galactose e sacarose. O pr?-tratamento dos camundongos com 3% de tioglicolato aumentou a popula??o de macr?fagos em 2,3 vezes o que provocou o aumento da migra??o de neutr?filos em 75,58% (p<0,0001) ap?s 24 horas da inje??o da CvL. No entanto, com a inje??o de fMLP n?o foi observado nenhum efeito significativo. O pr?-tratamento dos camundongos com dexametasona (cortic?ide antagonista de citocinas) reduziu a migra??o de neutr?filos em 65,6% (p<0,001), com diclofenaco ( antiinflamat?rio n?o ester?ide n?o seletivo) reduziu em 34,5% (p<0,001) e com Celecoxibe (antiinflamat?rio n?o ester?ide seletivo) n?o apresentou efeito. Os resultados do presente trabalho s?o indicativos de que a CvL possui atividade pr?-inflamat?ria, induzindo a migra??o de neutr?filos, provavelmente atrav?s da indu??o da libera??o de citocinas quimiot?cticas na ativa??o de macr?fagos residentes no perit?nio

Made available in DSpace on 2014-12-17T14:03:25Z (GMT). No. of bitstreams: 1 GiocondaEDDM.pdf: 827312 bytes, checksum: dd690ec78d2921013aa0e24b334bac19 (MD5) Previous issue date: 2007-12-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / In this study, a BCR-ABL expressing human chronic myelogenous leukaemia cell line (K562) was used to investigate the antitumoral potential of a novel lectin (CvL) purified from the marine sponge Cliona varians. CvL inhibited the growth of K562 cells with an IC50 value of 70 g/ml, but was ineffective to normal human peripheral blood lymphocytes in the same range of concentrations tested (180 g/ml). Cell death occurred after 72 h of exposure to the lectin and with sign of apoptosis as analysed by DAPI staining. Investigation of the possible effectors of this process showed that cell death occurred in the presence of Bcl-2 and Bax expression, and involved a caspase-independent pathway. Confocal fluorescence microscopy indicated a major role for the lysosomal protease cathepsin B in mediating cell death. Accordingly, pre-incubation of K562 cells with the cathepsin inhibitor L-trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64) abolished the cytotoxic effect of CvL. Furthermore, we found upregulation of tumor necrosis factor receptor 1 (TNFR1) and down-modulation of p65 subunit of nuclear factor kappa B (NF&#61547;B) expression in CvL-treated cells. These effects were accompanied by increased levels of p21 and downmodulation of pRb, suggesting that CvL is capable of cell cycle arrest. Collectively, these findings suggest that cathepsin B acts as death mediator in CvL-induced cytotoxicity possibly in a still uncharacterized connection with the membrane death receptor pathway / Neste trabalho, a linhagem K562 de c?lulas de leucemia miel?ide cr?nica, expressando a prote?na oncog?nica BCR-ABL, foi usada como modelo para investigar a atividade antitumoral da lectina CvL purificada da esponja marinha Cliona varians. CvL inibiu o crescimento de c?lulas K562 com um IC50 de 70 g/mL, mas n?o afetou a viabilidade celular de linf?citos normais de sangue perif?rico humano no mesmo intervalo de concentra??es testadas (1 80 g/mL). A morte celular ocorreu ap?s 72 horas de exposi??o ? lectina e com altera??es nucleares t?picas de apoptose como analisado pela fluoresc?ncia de DAPI. Investiga??o dos poss?veis efetores deste processo mostrou que a morte celular ocorreu sem ativa??o de caspases e na presen?a de express?es aumentadas de Bcl-2 e Bax. O fato de CvL desencadear a libera??o de catepsina B, como evidenciado pela microscopia de fluoresc?ncia, e do inibidor E-64 bloquear completamente a morte celular induzida por CvL, sugerem papel central dessa protease lisossomal na ativa??o de uma via alternativa de morte celular. CvL tamb?m induziu o aumento de express?o do receptor de morte TNFR-1 e a diminui??o dos n?veis de NF&#954;B. Estes efeitos foram acompanhados pelo aumento significativo na express?o de p21 e pela modula??o negativa de pRb, mostrando que CvL foi capaz de bloquear a progress?o do ciclo celular. Juntos, estes dados sugerem que catepsina B age como mediador da citotoxicidade induzida por CvL possivelmente atrav?s de uma conex?o ainda n?o caracterizada com a via dos receptores de morte

Bioerosion is a major process that affects the carbonate balance on coral reefs, and excavating sponges from the genus Cliona are some of the most important bioeroders on Caribbean reefs. The orange boring sponge, Cliona delitrix, is an abundant excavating sponge offshore southeast Florida that frequently colonizes dead portions of live stony corals, killing live coral tissue as it grows. With the recent decline in coral cover attributed to combined environmental and anthropogenic stressors, the increasing abundance of excavating sponges poses yet another threat to the persistence of Caribbean coral reefs. In the first part of this study, I explored distributional patterns of C. delitrix offshore southeast Florida and compared yearly sponge growth/corresponding coral tissue loss rates across habitats of different depths. C. delitrix densities and growth rates were significantly higher on the outer reef, where coral colonies also showed some of the fastest tissue retreat rates. More sponge individuals were found on sites with higher coral densities, likely resulting from the higher availability of preferred coral skeleton substrate. C. delitrix showed a clear preference for boulder stony coral species, which could alter the coral community composition in the future and allow an increase in branching and foliose species. The growth rates of C. delitrix offshore southeast Florida are slower compared to rates from other locations, likely a result of intense fouling of the coral-sponge interface by other spatial reef competitors. These results suggest that outer reef sites with high boulder coral density offshore southeast Florida are most vulnerable to C. delitrix colonization and may continue to suffer the greatest impacts of coral bioerosion. Excavating sponges are also strong competitors for space on coral reefs; able to colonize, excavate, and kill entire live stony corals. Despite the known negative effects of excavating sponges on stony corals very few studies have experimentally tested the competitive nature of this interaction. In the second part of this study, I examined the effect of manual removal of the excavating sponge, Cliona delitrix (Pang 1973), on tissue loss of the stony coral Montastrea cavernosa (Linnaeus 1767), and its possibility as a restoration technique. A total of 33 M. cavernosa colonies colonized by small C. delitrix sponges (up to 10 cm in diameter) were examined. Sponges were removed using a hammer and chisel from 22 of the affected colonies, and 11 colonies were left alone as controls. After sponge removal, the resultant cavities in the coral skeletons were filled to minimize future colonization by other bioeroders and promote coral tissue growth over the excavation. Cement was used as fill material on 11 of the colonies, and the remaining 11 cavities were filled with epoxy. Standardized photos of each colony were taken immediately, at 6 months and 12 months after sponge removal. Results show a significant reduction in coral tissue loss in colonies where sponge was removed, and both fill materials performed similarly reducing coral tissue loss. I also found that a majority of experimental corals showed no return of C. delitrix to the colony surface a year after removal. This study demonstrates that eliminating the bioeroding sponge competitor may promote recovery of the affected stony coral. Additionally, the sponge removal technique can be applied to any stony coral colonized by C. delitrix to preserve, or at least slow the loss of, remaining live tissue.