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Most of the theoretical and practical development of the ocean acidification (OA) phenomenon involves the open ocean, and not much is known of the significance of variation in pH and carbonate system in coastal environments and the effect, if any, of OA. Traditional potentiometric pH measurements are carried out on the NBS scale (pHNBS), developed for freshwaters, but for OA it is necessary to use the total scale (pHT), which includes the additional ions of seawater. Using a series of in-situ measurements of potential, carried out with a pHNBS electrode in the artificial coastal lagoon La Escollera in Santa Marta (Colombia), a methodology to calculate pHT was tested. For this, the equation pHT(X) = pHT(TRIS) - EX-ETRISR*T*ln10/F was used, which calculates pHT(X) of the sample from the pHT(TRIS) of the TRIS standard solution, the potentials E measured at temperature T, and the constants R and F. ETRIS was determined experimentally for the lagoon temperature range, and the linear regression showed a coefficient of determination (R2) of 0.9977. In a first qualitative analysis, it was verified that pH variations during the day-night cycle are closely associated with those of oxygen, from the production and consumption of CO2 by photosynthesis and respiration. These high-frequency variations are of greater magnitude than those of the open ocean, raising questions about the real effect of OA on coastal ecosystems.

The genus Placospongia Gray, 1867 is a group of sponges widely distributed in the world. It currently has 11 valid species, where five of those, Placospongia caribica Rützler et al., 2014, P. cristata Boury-Esnault, 1973, P. intermedia Sollas, 1888, P. ruetzleri van Soest, 2017 and P. giseleae Mácola & Menegola, 2021, are distributed in the Central Western Atlantic. The Colombian Caribbean has the records of P. intermedia and P. ruetzleri. In this research, the taxonomy of the genus Placospongia in Colombia was reviewed, describing four species, two of which are new to science: P. colombiensis sp. nov. and P. soesti sp. nov.; and P. cristata is a new record for the Colombian Caribbean. Therefore, the number of species of the genus is expanded to 13 for the world, to eight for the Western Atlantic, and to five for Colombia, ranking it as the country with the most species of the genus for the Western Atlantic. Some of the misassigned records for Indo‒Pacific species are relocated to species present in the Caribbean. Finally, a taxonomic key is given to identify the species of the Caribbean Sea.

En comparación con otros grupos de invertebrados, la taxonomía de esponjas (Porífera) ha sido poco desarrollada en el Pacífico Oriental Tropical (POT), en general, y en el Pacífico colombiano, en particular. Este trabajo busca incrementar el conocimiento de la biodiversidad del grupo en los arrecifes rocosos del norte del Chocó. Se recolectaron muestras de esponjas mediante buceo autónomo, las cuales fueron procesadas e identificadas en laboratorio por métodos estándar. Se confirmó la baja riqueza de especies y la predominancia de morfologías incrustantes y hábitos crípticos, que ha sido encontrada en otros estudios en la región. Se identificaron 24 morfotipos pertenecientes a 13 órdenes, 17 familias y 21 géneros. Doce (12) morfotipos se reconocieron a nivel de género o con identidad específica tentativa y los otros 12 fueron confirmados a nivel de especie. Seis (6) especies son morfológicamente similares a las del Caribe, lo que indica que las poblaciones posiblemente no han divergido lo suficiente desde el cierre del istmo de Panamá o, alternativamente, pueden haber cruzado recientemente el canal de Panamá.

Las lagunas costeras son foco de producción primaria y refugio de biodiversidad por su relativo confinamiento y baja profundidad. La Escollera es una laguna costera artificial situada en El Rodadero, Santa Marta (Caribe colombiano), excavada al inicio de la década de 1980 para albergar una marina y sus bordes sembrados con mangles. Para generar una línea base de variables físicas que contribuyan al entendimiento de la circulación del agua y de su influencia sobre los atributos del ecosistema, se obtienen de manera rutinaria datos de salinidad, temperatura, nivel del mar y penetración de la luz mediante registradores electrónicos y sensores de mano. Los datos de salinidad y temperatura entre enero de 2017 y febrero de 2018 siguieron el esquema estacional del mar abierto del área de Santa Marta alternando entre menor temperatura (mínima 24,6 °C) y mayor salinidad (máxima 38,9) en época seca y de afloramiento costero (diciembre a abril) y entre mayor temperatura (máxima 34,7 °C) y menor salinidad (< 35) en época de lluvia (mayo a noviembre), con los más bajos valores de salinidad luego de aguaceros persistentes (mínimo 15,1). La columna de agua está generalmente bien mezclada y se estratifica después de aguaceros en época de lluvia (mezclándose rápidamente en horas o en días). Esto parece deberse principalmente al intercambio con el mar gracias a la marea, que oscila de +0,37 a –0,31 m (rango máximo de 0,68 m [datos de un año]), y sigue el patrón astronómico regular de mareas mixtas del Caribe. Las aguas de la laguna son regularmente verdes y de variada transparencia excepto durante fuertes lluvias, tras lo cual se tornan pardas. La extinción de luz en la vertical es en general alta y no muy variable (2-6,5 % cm-1), pero la luz, con frecuencia, alcanza el fondo, lo que permite la existencia de macroalgas bentónicas en algunas porciones de la laguna.

Algal turfs are currently the most abundant benthic component on most coral reefs. Their wide distribution, functional role and positive responseto factors that stress corals confirm their importance in the functioning of reef ecosystem. It has been shown that species composition, structuraldevelopment and sediment retention influence their capacity to kill and displace adjacent live coral tissue. In this study in two reefs of the Tayrona National Natural Park (Colombian Caribbean), the variation in structure of turfs growing on and in direct interaction with massive live corals was determined,and its structural complexity was related with its sediment retention capacity. For that, the taxonomical composition was determined, and canopy height, cover and density of filaments and algal biomass were quantified for turfs growing on live colonies of four species of corals. The results showed that there are important structural differences between reefs and substratum type. In Granate reef (10-16 m), turfs form discontinuous carpets over crustose algae, and are constituted by articulated calcareous and little corticated algae, and juveniles of frondose algae, mostly of the genus Dictyota. During coastal upwelling, this genus grows profusely forming transient dense algal beds that later detach. In contrast, in Nenguange reef (4-6 m), turfs are perennial, form low, thick and dense carpets, with few crustose algae, and are dominated by filamentous and small corticated algae. It´s suggested that the presence of territories ofdamselfishes (Stegastes spp.) aid controlling the structural complexity of the turfs, and that vegetative propagation is the most frequent growth mechanism. In addition, it was found that the most morphologically complex turfs can retain greater amounts of sediments (silt-clay). This particulate material supports them; they can advance laterally and smother adjacent live coral tissue. This investigation provides the first quantitative data on the structure and amount of retained sediments by algal turfs growing on Colombian reef corals.

Las ramas muertas de Acropora palmata colonizadas por la esponja excavadora Cliona tenuis son propensas al desplazamiento, la rotura y la translocación durante fuerte oleaje o mar de fondo de tormentas o huracanes, lo que favorece la dispersión de esta esponja. En las islas del Rosario (Colombia, Caribe), los adultos de C. tenuis transportados por fragmentos de A. palmata que cayeron sobre corales masivos vivos colonizaron el nuevo coral y mataron posteriormente el tejido vivo del coral recién invadido. Los corales que reclutaron sobre las ramas caídas de A. palmata cubiertas de C. tenuis también fueron invadidos una vez que la esponja llegó a su base. Para determinar si la incidencia de este fenómeno aumentó desde 2002, cuando se documentó por primera vez, la prevalencia y el modo de colonización de corales por C. tenuis se cuantificó nuevamente en 2014, en el mismo arrecife. Aunque es difícil inferir una tendencia a partir de dos muestreos puntuales, el número de colonias de coral colonizadas por C. tenuis se duplicó en 2014 y se encontraron nuevos casos de colonización desde ramas de A. palmata portadoras de esponjas. Sin embargo, la frecuencia de colonización por esponjas adultas desde las ramas de A. palmata en 2014 fue entre la mitad y un quinto menor que en 2002, lo que sugiere que otras formas de colonización en corales masivos pueden estar aumentando o que las tormentas borran la evidencia de adultos colonizadores por la translocación de las ramas de coral que han servido de vectores, como se observó en un caso monitoreado. A medida que pasa el tiempo y aumenta la fragmentación y la erosión del arrecife, la evidencia de colonización de corales pétreos por C. tenuis a través de las ramas de A. palmata se desvanece.

In tropical seas there are submerged hard bottoms that harbor corals but that are not coralline in origin. This is the case for the “Banco de las Ánimas” sector in the continental shelf of the Gulf of Salamanca, Colombian Caribbean. In its upper portion (14–16 m in depth), there are low mounds of sandstone blocks and slabs, conforming reefs, colonized by coralline biota and sparse corals. To confirm their lithology an initial petrographic analysis was carried out, which showed the rocks are made up of fine-grained sands, mature in texture, cemented by dolomite. It is proposed that these reefs were formed in a beach–dune–lagoon system during an ancient sea level, similar to the recent coastal bar of Salamanca. In these high-evaporation, supratidal saline environments, they could have been formed as beach rocks or as eolianites, by aragonite cementation, modified later into dolomite. Whether the foundation of the deeper coral formations of the bank is also sandstone or in fact coralline, remains to be determined.

El mar territorial colombiano, con costas en el mar Caribe y el océano Pacífico, comprende unos 2.070.408 km2, lo cual significa que cerca del 50% del territorio nacional es marítimo. A través de este libro se hace una invitación a las generaciones actuales y futuras a ejercer soberanía, defender y cuidar este bien, para conservar la biodiversidad en nuestras costas, de forma responsable y con equidad, en consideración a los costos ambientales de cada una de las dinámicas de desarrollo costero. Se debe garantizar a Se debe garantizar a nuestros hijos y nietos un ambiente sano y la posibilidad de vivir y disfrutar de los múltiples beneficios que proveen tan extensos, ricos y biodiversos ecosistemas marinos costeros, tales como el oxígeno, alimento, medicinas, protección contra la erosión costera y recreación, entre otrosSe debe garantizar a nuestros hijos y nietos un ambiente sano y la posibilidad de vivir y disfrutar de los múltiples beneficios que proveen tan extensos, ricos y biodiversos ecosistemas marinos costeros, tales como el oxígeno, alimento, medicinas, protección contra la erosión costera y recreación, entre otrosnuestros hijos y nietos un ambiente sano y la posibilidad de vivir y disfrutar de los múltiples beneficios que proveen tan extensos, ricos y biodiversos ecosistemas marinos costeros, tales como el oxígeno, alimento, medicinas, protección contra la erosión costera y recreación, entre otros.

Five demosponges belonging to the order Axinellida: Axinella corrugata, Dragmacidon alvarezae, Dragmacidon reticulatum, Ptilocaulis walpersi, Myrmekioderma rea and one sponge belonging to the order Scopalinida: Scopalina ruetzleri were analyzed to assess their fatty acid composition in the phospholipid fraction. Additionally, the seasonal and intraspecific variation in fatty acids composition was assessed in M. rea and D. alvarezae. Fatty acid identification was conducted using an HRGC-MS with an ECL value of methyl ester derivatives, and analyzing their mass spectra. To confirm double bound location, N-acylpyrrolidide derivatives were used studying their mass spectra. In total, 83 fatty acids were identified with chain lengths ranging from C14 to C32. Interestingly, brominated fatty acids were identified, previously suggested for sponges. Polybranched fatty acids such as 4,8,12-trimethyltridecanoic acid (4,8,12-TMTD) and 3,7,11,15-tetramethylhexadecanoic (phytanic acid) were found, without a clear distribution pattern. A predominance of iso-acids (i-15:0 and i-17:0) on anteiso acids were observed. Some seasonal variations in fatty acid (FA) compositions for M. rea and D. alvarezae were observed. The hierarchical Clusters Analysis (HCA) showed that the FA composition was species-specific but not informative at the family or order level.

El incremento en la frecuencia e intensidad de eventos oceanicos extremos limita la capacidad de recuperacion de los ecosistemas, amenazando su subsistencia. Con el fin de entender la relacion entre la estructura y salud arrecifal y los eventos extremos ambientales, se analizaron series de datos ambientales de las islas del Rosario ( e.g ., temperatura del mar, caudal y/o salinidad, turbidez), en comparacion con cobertura coralina y signos de deterioro ( e.g ., blanqueamiento, enfermedades). En las series de tiempo de las variables ambientales se calcularon los eventos oceanicos que excedieron un umbral estadistico, estableciendo su intensidad, duracion y frecuencia. Para los atributos de la comunidad, se evaluaron dos estaciones del Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC), en dos ventanas temporales (largo plazo, 1998–2013 y corto plazo, 2013 - 2014). Los eventos extremos de temperatura superficial del mar, el caudal de descarga continental y la turbidez asociada fueron las principales variables relacionadas con la reduccion de la cobertura coralina. El blanqueamiento masivo de 2005 y otros eventos posteriores dieron como resultado una reduccion de la cobertura coralina entre 2004 y 2010. En el corto plazo no se registraron fuertes eventos extremos ni cambios en las formaciones coralinas, si bien el estres termico y las reducciones de salinidad en la epoca de lluvias estuvieron asociados con un ligero blanqueamiento en noviembre de 2014. Aunque los signos de deterioro sean bajos, es importante considerarlos, ya que la sinergia entre perturbaciones continuas puede conllevar a una perdida de cobertura del coral. Effect of extreme oceanic events in the coral formations of Islas del Rosario, Colombian Caribbean The increase in frequency and intensity of extreme oceanic events limits the capacity of recovery of ecosystems, threatening their subsistence. Thus, in order to understand the relationship between coral health and extreme environmental events, data on sea temperature, runoff and / or salinity, turbidity were analyzed in the Islas del Rosario in comparison with coral cover, and coral signs of deterioration ( e.g ., bleaching, coral diseases). In the time series of environmental variables, oceanic events that exceeded a statistical threshold were calculated, establishing their intensity, duration and frequency. The attributes of the community were studied through observations in two stations of the National Coral Reef Monitoring System in Colombia (SIMAC), assessed in two time windows (long term, 1998-2013 and short term, 2013-2014). The extreme events of sea surface temperature, river discharge and associated turbidity, were the main variables related to the reduction of coral cover. The massive coral bleaching of 2005 and other subsequent events resulted in a reduction in coral coverage between 2004 and 2010. During the short-term observations there were no strong extreme events or changes in coral formations, although thermal stress and reductions in salinity in the rainy season were associated with a slight bleaching in November 2014. Although the signs of deterioration are low, it is important to consider them, since the synergy between continuous disturbances can lead to a loss of coral cover.

Sponges (Porifera) are important constituents of littoral habitats in the Caribbean Sea.The knowledge of their biodiversity is fundamental to carry out ecological, managerial and utilitarianresearch. Their taxonomy is complex, but in the Caribbean in general, and in Colombia in particular, thereare important advances. With this work, some sponge species of the genera Petrosia and Xestospongiaare recorded and described for the first time from the Colombian Caribbean. Petrosia (Strongylophora)davilai, Xestospongia arenosa, Xestospongia deweerdtae and Xestospongia purpurea are described andillustrated. The number of records of Petrosia and Xestospongia for the Colombian Caribbean are nowthree and four species, respectively. In all species, the specimens from continental localities had largerspicule sizes than those from insular localities, apparently owing to a greater availability of dissolvedsilicon in the former. The existence in Xestospongia deweerdtae of free-living and Plakortis-associatedlifestyles was documented for new areas of the Caribbean.

The Caribbean soft coral Erythropodium caribaeorum is a rich source of erythrolides&mdash, chlorinated briarane diterpenoids. These compounds have an ecological role as feeding deterrents, with a wide variation in their composition depending on the location where the sample is collected. In Colombia, this soft coral can be found at different locations in the Caribbean Sea including Santa Marta, Islas del Rosario, and Providencia&mdash, three environmentally different coral reef areas in the south and southwest Caribbean Sea. In order to evaluate differences in erythrolide composition, the metabolic profiles of samples from each of these locations were analyzed by HPLC-MS. Principal component analysis showed changes in the diterpene composition according to the sample origin. Diterpenes from samples collected at each location were isolated to describe the three chemotypes. The chemotype from Santa Marta was highly diverse, with the new erythrolides W and X together with eight known erythrolides. The sample from Islas del Rosario showed a low diversity chemotype constituted by high amounts of erythrolide A and B. The chemotype from Providencia showed low chemical diversity with only two main compounds&mdash, erythrolide V and R. Evaluation of cytotoxic activity against the human cancer cell lines PC-3, MCF7, and A549 showed erythrolides A and B as the more active compounds with IC50 values in the range from 2.45 to 30 &mu, M.

RESUMEN En los arrecifes de coral, la competencia entre organismos bentónicos sésiles por acceso a espacio y otros recursos es determinante en la estructuración de las comunidades. La mortalidad coralina reciente ha favorecido el desarrollo de céspedes algales que pasan a competir con los corales, a menudo desplazándolos, aunque lentamente. Para determinar qué tan frecuentes son las interacciones coral-césped y coral-otras categorías bentónicas, y cómo su distribución y resultado (coral gana o coral pierde) son modulados por factores ambientales, se evaluaron fototransectos de banda en 12 estaciones del Parque Nacional Natural Tayrona en Santa Marta, Caribe colombiano. Se encontró que los céspedes algales son el competidor más frecuente de corales masivos así como que la frecuencia de interacciones coral-césped depende de la susceptibilidad particular de una especie de coral a perder tejido y de las perturbaciones que en conjunto afectaron el arrecife donde habita. Además, el resultado de estas interacciones dependió del tipo de organización colonial, siendo las colonias de tipo meandroide y cerioide los competidores más exitosos contra los céspedes, debido al mecanismo de evasión por crecimiento en altura, mientras que las colonias de tipo plocoide fueron más propensas a perder. En general, los factores biológicos (especie de coral y tipo de organización colonial) fueron determinantes en la frecuencia y resultado aparente de las interacciones coral-césped, en tanto que los factores ambientales (gradiente de perturbación, profundidad y grado de exposición al oleaje) parecen no desempeñar un papel preponderante. Por lo tanto, los cambios históricos y futuros en cobertura de cada especie coralina y el tipo de organización colonial en el área de Santa Marta deben reflejar una combinación entre su susceptibilidad a agentes deletéreos y su capacidad de contrarrestar o evadir la competencia, especialmente con céspedes algales. ABSTRACT In coral reefs, competition between sessile benthic organisms for access to space and other resources is a determining factor in community structuring. Recent coral mortality has favored the development of algal turfs, which are now competing with corals, often displacing them, although slowly. To determine the frequency of interactions between coral-turf and coral-other benthic categories, and how their distribution and results (coral wins or coral loses) are modulated by environmental factors, band photo transects were evaluated for 12 stations in the Parque Nacional Natural Tayrona, Santa Marta, Colombian Caribbean. It was found that algal turfs are the most frequent competitors of massive corals, and that the frequency of coral-turf interactions depends on the particular susceptibility of a coral species to the loss of tissue, and past disturbances that have affected the reef in which it lives. Furthermore, the results of these interactions depend on the ways the colonies are organized, meandroid and cerioid colonies being the most successful in competition against turfs, as their vertical growth constitutes an effective avoidance mechanism. By contrast, plocoid colonies are more prone to lose. In general, biological factors (the coral species in question and type of colonial organization) were determinants in the frequency and apparent result of coral-turf interactions, while environmental factors (disturbance gradient, depth, and degree of wave exposure) appear not to play a predominant role. As a consequence, historical and future changes in coral species cover, and the nature of colony organization in the Santa Marta area, should reflect a combination of their susceptibility to deleterious agents and their capacity to counteract or evade competition, especially with algal turfs.

RESUMEN La formación de biopelículas es un proceso importante para las comunidades bacterianas marinas debido a que este mecanismo favorece la adaptación a variaciones en las condiciones ambientales. El objetivo de este estudio fue evaluar la formación de biopelículas de las bacterias aisladas de sedimentos marinos en condiciones in vitro. Para esto se realizaron ensayos de cuantificación de biopelículas usando dos métodos, cristal violeta y reducción del colorante XTT; además se evaluó la viabilidad de las bacterias mediante la tinción Live/Dead. Posteriormente las cepas evaluadas fueron identificadas usando el marcador 16S ARN. Los resultados mostraron que los aislados pertenecen al género Bacillus todos en diferentes rangos fueron capaces de formar películas y se seleccionaron las cepas B. safensis 64181 y Bacillus sp 64186 las cuales indicaron mayor producción de esta. Los ensayos a diferentes temperaturas demostraron que para las cepas seleccionadas la mejor temperatura fue de 28°C. Además se realizó un cultivo mixto con estos aislados obteniendo como resultado diferencias en la densidad de la biopelícula y menos cambios en la actividad metabólica de la misma en los experimentos de variación de temperatura. A partir de los resultados podemos inferir que los consorcios bacterianos pueden favorecer la resistencia a variaciones ambientales en las biopelículas formadas por bacterias del género Bacillus. ABSTRACT Biofilm formation is an important process for marine bacterial communities because this mechanism favors adaptation to variations in environmental conditions. The objective of this study was to evaluate the biofilm formation of bacteria isolated from marine sediments under in vitro conditions. For this, biofilm quantification assays were performed using two methods, violet crystal and reduction of the XTT dye; In addition, the viability of the bacteria was evaluated by Live / Dead staining. Subsequently, the strains evaluated were identified using the 16S RNA marker. The results showed that the isolates belong to the genus Bacillus, all in different ranges were able to form films and strains B. safensis 64181 and Bacillus sp 64186 were selected which indicated greater production of this. Tests at different temperatures showed that for the strains selected the best temperature was 28 ° C. In addition, a mixed culture was carried out with these isolates, resulting in differences in the density of the biofilm and less changes in its metabolic activity in temperature variation experiments. From the results we can infer that bacterial consortiums can favor resistance to environmental variations in biofilms formed by bacteria of the genus Bacillus.

RESUMEN En los mares tropicales hay fondos duros sumergidos que albergan corales pero que no son de origen coralino. Este es el caso del sector del Banco de las Ánimas, en la plataforma continental del golfo de Salamanca, mar Caribe colombiano. En su parte superior (14-16 m de profundidad) hay montículos bajos de bloques y lajas de arenisca, a manera de arrecifes, colonizados por biota coralina y corales dispersos. Para confirmar su fitología, se realizó un primer análisis petrográfico, que mostró que las rocas están conformadas por arenas de grano muy fino, maduras en textura, cementadas por dolomita. Se propone que estos arrecifes fueron formados en un sistema playa-duna-laguna de un antiguo nivel del mar, similar a la actual barra costera de Salamanca. En estos ambientes supramareales salinos de alta evaporación, se pudieron formar como rocas de playa o como eolianitas, por cementación de aragonita, que fue convertida posteriormente en dolomita. Falta determinar si el basamento de las formaciones coralinas de mayor profundidad del Banco también es de arenisca, o es efectivamente coralino. ABSTRACT In tropical seas there are submerged hard bottoms that harbor corals but that are not coralline in origin. This is the case for the "Banco de las Ánimas" sector in the continental shelf of the Gulf of Salamanca, Colombian Caribbean. In its upper portion (14-16 m in depth), there are low mounds of sandstone blocks and slabs, conforming reefs, colonized by coralline biota and sparse corals. To confirm their lithology an initial petrographic analysis was carried out, which showed the rocks are made up of fine-grained sands, mature in texture, cemented by dolomite. It is proposed that these reefs were formed in a beach-dune-lagoon system during an ancient sea level, similar to the recent coastal bar of Salamanca. In these high-evaporation, supratidal saline environments, they could have been formed as beach rocks or as eolianites, by aragonite cementation, modified later into dolomite. Whether the foundation of the deeper coral formations of the bank is also sandstone or in fact coralline, remains to be determined.

Neopetrosia proxima(Porifera: Demospongiae: Haplosclerida) is described as a morphologically variable sponge common on shallow reefs of the Caribbean. However, the range of morphological and reproductive variation within putativeN. proximaled us to hypothesize that such variability may be indicative of cryptic species rather than plasticity. Using DNA sequences and morphological characters we confirmed the presence of three previously undescribed species ofNeopetrosia. Morphological differences of each new congener were best resolved by partial gene sequences of the mitochondrial cytochrome oxidase subunit 1 over nuclear ones (18S rRNA and 28S rRNA). Several new characters forNeopetrosiawere revealed by each new species. For example,N. dendrocrevaceasp. nov. andN. cristatasp. nov. showed the presence of grooves on the surface of the sponge body that converge at the oscula, and a more disorganized skeleton than previously defined for the genus.N. sigmaferasp. nov. adds the (1) presence of sigma microscleres, (2) significantly wider/longer oxeas (>200 μm), and (3) the presence of parenchymella larvae. Sampling of conspecifics throughout several locations in the Caribbean revealed larger spicules in habitats closer to the continental shelf than those in remote island locations. Our study highlights the importance of integrating molecular and morphological systematics for the discrimination of newNeopetrosiaspp. despite belonging to one of several polyphyletic groups (families, genera) within the current definition of the order Haplosclerida.

Esta investigacion busco determinar el papel de la herbivoria por parte del caracol Cittarium pica sobre el ensamblaje algal del litoral rocoso en el area de Santa Marta, Colombia. Se realizaron experimentos con jaulas en el mesolitoral superior entre diciembre de 2017 y junio de 2018, con tratamientos de inclusion ( C. pica ), exclusion (sin herbivoros) y controles (2 lados abiertos y sin jaula). La disminucion natural de las algas durante la epoca de lluvia se vio reforzada en abril, cuando se combinaron por varios dias mar calmo y mareas bajas al medio dia, produciendo altas temperaturas y desecacion que generaron mortandad masiva. Se observo una mayor cobertura de algas coralinas incrustantes en los tratamientos con C. pica , insinuando que las favorece el pastoreo, sobre ellas o sobre otros grupos de algas. En general, la herbivoria por C. pica no parecio controlar al ensamblaje algal. Esto podria deberse a que en la poblacion, actualmente dominan ejemplares de tallas pequenas como consecuencia de la sobreexplotacion, lo que los limita fisicamente para la ingesta de algas de mayor tamano y textura firme. Las algas fueron estimuladas principalmente por el afloramiento costero y controladas por factores ambientales, que a veces pueden ser extremos.

Slattery & Lesser (2015; Mar Ecol Prog Ser 527:275-279) offer a Comment on our review of the literature for evidence of bottom-up control of sponge communities on Caribbean reefs. We briefly address the criticisms presented in the Comment and reiterate the lack of evi- dence for food limitation, including inter-oceanic comparisons of Caribbean reefs with Indo- Pacific oligotrophic reefs, where sponge communities show strong evidence of food limitation, and past and recent evidence for the importance of dissolved organic carbon (DOC) in sponge nutri- tion. We did not claim that 'predation is the primary process that determines the growth, biomass and biodiversity of sponges on Caribbean coral reefs,' but we identified 3 depth-related factors that influence sponge community structure on Caribbean reefs: turbulence, spatial competition and predation. We agree that multifactorial manipulative experiments are the best way to address the interaction between top-down and bottom-up processes in this system; indeed, one such experiment has been performed, with an outcome that does not support bottom-up effects.

The diversity and biomass of sponges on Caribbean reefs exceeds that of all other benthic organisms. Wilkinson & Cheshire (1990; Mar Ecol Prog Ser 67:285�294) summarized evi- dence that sponge communities on Caribbean reefs were different from those on the Great Barrier Reef, Australia, reflecting food limitation of the latter, but not of the former. Since then, we have learned much about the ecology of sponges, and the concept of food limitation has recently re- emerged, seemingly without substantive reference to past inter-oceanic comparisons or pioneer- ing studies of sponge physiology. Here, we review the literature in an attempt to correct this digression. Based on current knowledge of sponge nutrition and bottom-up resource gradients (particulate food, dissolved organic carbon (DOC), light, turbulence), we predict 4 patterns of sponge abundance that would suggest food limitation on Caribbean reefs. After a critical review of survey data, correlative studies and manipulative experiments, we can find no evidence for food limitation. Although there is good evidence for higher availability of picoplankton at greater depths, sponge abundance does not mirror this gradient, suggesting that other sources of nutrition are also important, and particulate food is not a limiting factor. Recent studies have renewed inter- est in the uptake of DOC by both high and low microbial abundance sponge species, suggesting that the absence of bottom-up effects for sponges on Caribbean reefs may be attributable to this mysterious, and likely ubiquitous, food source. The recent unambiguous demonstration of top- down effects of predation on sponge community composition across the Caribbean may owe its clarity to the relative lack of confounding influences of abiotic and bottom-up effects in this study system.

RESUMEN El macrólido antitumoral (+)-discodermólido, producido por la esponja marina Discodermia dissoluta, tiene promisorios resultados como antitumoral, antimitótico e inmunosupresor. Sin embargo, el suministro sostenible de cualquier molécula necesita mucha investigación de trabajo in situ e in vitro para lograr la optimización y posterior obtención de la molécula de interés. En este estudio se evaluaron dos sistemas de cultivo fijo y suspendido a 15 m de profundidad, en las localidades de Punta de Betín y Nenguange en Santa Marta (Caribe colombiano). En cada caso se registró la supervivencia, el crecimiento y la producción de (+)-discodermólido, encontrando mejores resultados para el crecimiento en el sistema suspendido y una dependencia de la supervivencia según la localidad del cultivo. También se estudió la influencia de diferentes factores ambientales sobre la supervivencia, observando una correlación negativa con la temperatura. La salinidad, radiación solar, materia orgánica y flujo del agua no presentaron variaciones importantes, impidiendo establecer una correlación. En cuanto a la producción de (+) -discodermólido, no se encontraron diferencias significativas entre los sistemas y localidades, registrando una producción entre 20-270 pg por gramo de esponja seca. ABSTRACT The macrolide (+)-discodermolide produced by the marine sponge Discodermia dissoluta shows promising antitumor, antimitotic, and immunosuppressive activity. However, the sustainable supply of any molecule requires much in situ and in vitro research to optimize and later obtain the molecule of interest. In this study, two culture systems-fixed and suspended-were evaluated at 15-m depth in two sites, Punta de Betín and Nenguange, in Santa Marta (Colombian Caribbean). Survival, growth, and production of (+)-discodermolide were recorded, with the suspended system resulting in better growth and survival, depending on the culture site. The influence of the different environmental factors on survival was also studied, and a negative correlation with temperature was observed. Salinity, solar radiation, organic matter, and water flow were not correlated. Finally, no significant differences in the production of (+)-discodermolide existed between the culture systems and study sites. Production ranged from 20 to 270 μg per gram of dry sponge.

The macrolide (+)-discodermolide produced by the marine sponge Discodermia dissoluta shows promising antitumor, antimitotic, and immunosuppressive activity. However, the sustainable supply of any molecule requires much in situ and in vitro research to optimize and later obtain the molecule of interest. In this study, two culture systems—fixed and suspended—were evaluated at 15-m depth in two sites, Punta de Betín and Nenguange, in Santa Marta (Colombian Caribbean). Survival, growth, and production of (+)-discodermolide were recorded, with the suspended system resulting in better growth and survival, depending on the culture site. The influence of the different environmental factors on survival was also studied, and a negative correlation with temperature was observed. Salinity, solar radiation, organic matter, and water flow were not correlated. Finally, no significant differences in the production of (+)-discodermolide existed between the culture systems and study sites. Production ranged from 20 to 270 μg per gram of dry sponge.

Coral reefs supply millions of people with ecosystem goods and services, especially those living along tropical coastlines. Unfortunately, these ecosystems are disappearing at an alarming pace. In the Caribbean, the rate of coral loss is high (5.5 – 9.2% per year) and constant. In 2013, a healthy coral reef was discovered in one of the least expected places within the Colombian Caribbean: at the entrance of Cartagena Bay, a highly-polluted system that receives industrial and sewage waste, as well as high sediment and freshwater loads from an outlet of the Magdalena River (the longest and most populated river basin in Colombia). Here we provide the first characterization of Varadero Reef’s geomorphology and biological diversity. We also compare these characteristics with those of a nearby reference reef, Barú Reef, located in an area much less influenced by the described polluted system. Below the murky waters, we found high coral cover of 45.1% (± 3.9; up to 80% in some sectors), three species of lobster, eight of sea urchin, a fish community composed by 61 species from 24 families, and the typical zonation of a Caribbean fringing reef. All attributes found correspond to a reef that, according to current standards should be considered in "good condition". Current plans to dredge part of Varadero threaten the survival of this reef and could hinder efforts to uncover the underpinnings of this reef’s remarkable resilience. There is, therefore, an urgent need to describe the location and characteristics of Varadero as a first step towards gaining acknowledgement of its existence and garnering inherent legal and environmental protections.

International audience; Although sponges are important components of benthic ecosystems of the Caribbean Sea, their diversity remained poorly investigated in the Lesser Antilles. By organizing a training course in Martinique, we wanted both to promote taxonomy and to provide a first inventory of the sponge diversity on this island. The course was like a naturalist expedition, with a field laboratory and a classroom nearby. Early-career scientists and environmental managers were trained in sponge taxonomy. We gathered unpublished data and conducted an inventory at 13 coastal sites. We explored only shallow water habitats (0-30 m), such as mangroves, reefs or rocky bottoms and underwater caves. According to this study, the sponge fauna of Martinique is currently represented by a minimum of 191 species, 134 of which we could assign species names. One third of the remaining non-identified sponge species we consider to be new to science. Martinique appears very remarkable because of its littoral marine fauna harboring sponge aggregations with high biomass and species diversity dominating over coral species. In mangroves, sponges cover about 10% of the surface of subtidal roots. Several submarine caves are true reservoirs of hidden and insufficiently described sponge diversity. Thanks to this new collaborative effort, the Eastern Caribbean has gained a significant increase of knowledge, with sponge diversity of this area potentially representing 40% of the total in the Caribbean Sea. We thus demonstrated the importance of developing exploratory and educational research in areas historically devoid of biodiversity inventories and systematics studies. Finally, we believe in the necessity to consider not only the number of species but their distribution in space to evaluate their putative contribution to ecosystem services and our willingness to preserve them.

Three new cases of sponge symbiosis between species of Plakortis and Xestospongia were found in reef caves and mesophotic reef habitats of the Caribbean. Plakortis sp. 1 from the Bahamas associates exclusively with Xestospongia deweerdtae which was originally described living freely on the deep fore-reef and caves of Jamaica. In addition, we found Plakortis sp. 2 from Puerto Rico which associates with both X. deweerdtae and a different Xestospongia sp. Sponge specimens were identified using cytochrome oxidase subunit 1, 28S rRNA and 18S rRNA gene sequence fragments, spicule analysis, and histological sections with SEM. Unlike previous sponge pairs, Xestospongia spp. not only grew as a thin veneer of tissue over the Plakortis host sponge but through the mesohyl, forming inner channels (0.1–1 cm) that may provide a benefit by facilitating more efficient water transport through the dense Plakortis tissue. Symbioses with both Plakortis spp. were documented from an early recruit stage through adulthood. Spicule measurements conducted on symbiotic versus free-living X. deweerdtae revealed significantly smaller spicule sizes for symbiotic individuals, suggesting a cost in terms of silicon availability, or a benefit in terms of a lower investment in skeleton synthesis for support. This study reveals new specialized symbiotic associations between distantly related sponge genera that likely represent an alternative strategy of adaptation for life in reef caves and mesophotic reefs.

Exploration of continental shelves may produce unexpected faunal records. In shelf waters of La Guajira peninsula, Colombia, in the northern tip of South America, southern Caribbean Sea, we found a new species of Rhaphidhistia (Demospongiae, Hadromerida, Trachycladidae) a genus previously thought to be restricted to the Indo-Pacific Ocean. Rhaphidhistia guajiraensis sp. nov. is thickly encrusting, agglutinating bottom debris; it possesses asymmetric oxea as megascleres (465–757 μm by 6.3–17.5 μm) and spiraster-like spinispirae (15–37 μm by 2–5 μm). It is closely similar to the type species of the genus, R. spectabilis Carter, 1879, both standing apart from a third species, R. mirabilis (Dendy, 1924), thus conforming a natural group whose taxonomic placement needs to be reassessed. There are numerous cases of sponge genera with sister species in the Indo-Pacific and the Atlantic Oceans, possibly split since the Tethys Sea breakup; owing to their restricted or deep distribution, they are just starting to be discovered.

Biotechnological research on marine organisms, such as ex situ or in situ aquaculture and in vitro cell culture, is being conducted to produce bioactive metabolites for biomedical and industrial uses. The Caribbean marine sponge Discodermia dissoluta is the source of (+)-discodermolide, a potent antitumoural polyketide that has reached clinical trials. This sponge usually lives at depths greater than 30 m, but at Santa Marta (Colombia) there is a shallower population, which has made it logistically possible to investigate for the first time, on ways to supply discodermolide. We thus performed in situ, 6-month fragment culture trials to assess the performance of this sponge in terms of growth and additional discodermolide production and studied possible factors that influence the variability of discodermolide concentrations in the wild. Sponge fragments cultured in soft mesh bags suspended from horizontal lines showed high survivorship (93 %), moderate growth (28 % increase in volume) and an overall rise (33 %) in the discodermolide concentration, equivalent to average additional production of 8 μg of compound per millilitre of sponge. The concentration of discodermolide in wild sponges ranged from 8 to 40 μg mL(-1). Locality was the only factor related to discodermolide variation in the wild, and there were greater concentrations in peripheral vs. basal portions of the sponge, and in clean vs. fouled individuals. As natural growth and regeneration rates can be higher than culture growth rates, there is room for improving techniques to sustainably produce discodermolide.

Several groups of sponges are able to excavate galleries and tunnels in calcareous substrata such as limestone rock, shells, calcareous algae and coral skeletons. Within the genus Cliona, some species share the common traits of being brown to olive-green in color, and harboring photosynthetic, unicellular dinoflagellates (zooxanthellae). These Cliona spp. have been grouped as the Cliona viridis species complex. Several species of this complex completely encrust the excavated substratum with a thin veneer of tissue and, when colonizing dead exposed parts of live coral colonies, they are able to undermine or overgrow and thus kill live coral tissue as they advance predominantly laterally. In the course of our taxonomic and ecological studies of Caribbean brown to brown-black encrusting Cliona, we found an as yet undescribed species that stands out by having tylostyle megasclere spicules with narrow heads and lacking the usual microsclere spicule complement of spirasters. This species, named and described here Cliona acephala n. sp., has so far been found exclusively in the Santa Marta area, Caribbean coast of Colombia. Previous studies with ITS2 ribosomal DNA showed it to be genetically distinct from other Caribbean encrusting species belonging to the Cliona viridis species complex, vis. Cliona aprica, Cliona caribbaea, Cliona tenuis and Cliona varians, but making it genetically closer to Indo-Pacific Cliona orientalis. An intriguing possibility, to be addressed with further studies, is that C. acephala n. sp. may have been introduced to the Caribbean. However, until proved otherwise, we regard the material presently described as distinct.

The new discovery by Vicente et al. (2014) of specialized epizoic symbioses between sponges of the genera Plakortis and Xestospongia revealed the obligate interaction of two new Plakortis spp. associating with Xestospongia deweerdtae and a new Xestospongia sp. In this study we formally describe the two new Plakortis spp. as Plakortis deweerdtaephila sp. nov. (previously reported as Plakortis sp. 1), Plakortis symbiotica sp. nov. (previously reported as Plakortis sp. 2) and describe the new Xestospongia sp. epibiont as Haliclona ( Halichoclona ) plakophila sp. nov. Plakortis deweerdtaephila associates only with X. deweerdtae , and has very small to large straight diods (24.2–233.7 μm long) and triods (26.4–102.6 μm long) that form large ectosomal circular meshes (114–329 μm diameter). P. symbiotica associates with both X. deweerdtae and H. plakophila, has larger curved diods (71.9–141.8 μm long) and triods (20.4–70.6 μm long) that form smaller ectosomal circular meshes (43–121 μm diameter) than P. deweerdtaephila . Phylogenetic analysis of cox1 and cob gene fragments revealed a strongly supported clade that grouped both Plakortis spp. nov. distantly from any other known Plakortis spp. H. plakophila is described as a thin encrusting veneer of tissue with occasional papillae, so far only found associated with P. symbiotica in La Parguera, Puerto Rico. Phylogenetic analysis of 18S rRNA and cox1 gene fragments place it distantly from any known clade of Haplosclerida. We found a new associated morphotype of X. deweerdtae from Bocas del Toro Panama, which completely overgrew P. deweerdtaephila . In addition, free-living morphotypes from Panama produce larger S-shaped and round bracket shaped strongyles never before observed for this species, leading us to redescribe X. deweerdtae . All X. deweerdtae morphotypes shared >99% sequence homology of cox1 , 18S rRNA and 28S rRNA genes with the holotype of X. deweerdtae . This study highlights the highly variable morphological characters of X. deweerdtae influenced by lifestyle and environmental factors. This is also the first time that an obligate symbiosis with a heterospecific sponge is used as a key taxonomic character.

Changes in coral-sponge interactions can alter reef accretion/erosion balance and are important to predict trends on current algal-dominated Caribbean reefs. Although sponge abundance is increasing on some coral reefs, we lack information on how shifts from corals to bioeroding sponges occur, and how environmental factors such as anomalous seawater temperatures and consequent coral bleaching and mortality influence these shifts. A state transition model (Markov chain) was developed to evaluate the response of coral excavating sponges (Cliona delitrix Pang 1973) after coral bleaching events. To understand possible outcomes of the sponge-coral interaction and build the descriptive model, sponge-corals were monitored in San Andres Island, Colombia (2004-2011) and Fort Lauderdale, Florida (2012-2013). To run the model and determine possible shifts from corals to excavating sponges, 217 coral colonies were monitored over 10 years (2000-2010) in Fort Lauderdale, Florida, and validated with data from 2011 to 2015. To compare and test its scalability, the model was also run with 271 coral colonies monitored in St. Croix, U.S. Virgin Islands over 11 years (2004-2011), and validated with data from 2012-2015. Projections and sensitivity analyses confirmed coral recruitment to be key for coral persistence. Excavating sponge abundance increased in both Fort Lauderdale and St. Croix reefs after a regional mass bleaching event in 2005. The increase was more drastic in St. Croix than in Fort Lauderdale, where 25% of the healthy corals that deteriorated were overtaken by excavating sponges. Projections over 100 years suggested successive events of moderate coral mortality could shift algae-coral dominated reefs into algae-sponge dominated. The success of excavating sponges depended of the intensity of coral bleaching and consequent coral mortality. Thus, the proportion of Cliona delitrix excavating sponges is a sensitive indicator for the intensity and frequency of recent disturbance on Caribbean coral reefs. This article is protected by copyright. All rights reserved.

Although there is a long history of taxonomic investigation in Caribbean sponges, there are still many undescribed species. Furthermore, field observations and corroborating morphological analyses are revealing that what was believed to be single, somewhat variable species, may consist of two or more species, often easier to distinguish once well characterized. This is the case for Dragmacidon reticulatum (RidleyDendy, 1886) (Porifera, Demospongiae, Axinellida, Axinellidae), a rather well-known sponge, with an ample distribution and presence in rocky and reef environments of the tropical and subtropical Western Atlantic, with local records in the majority of the countries of the area, from Bermuda to Brazil. Field observations and a detailed review of material from different areas, including some type specimens, led us to the distinction of two different species in terms of external morphology, size of spicules, and skeletal architecture. The distinction was confirmed in the Bahamas and Santa Marta, Colombia, where the two species coexist. One of the species is Dragmacidon reticulatum sensu stricto, but for the other there is need to erect a new name, for which we propose Dragmacidon alvarezae n. sp. The purpose of the present work is to describe, illustrate and compare these two species.

Species complexes – groups of closely related species in which intraspecific and interspecific variability overlap – have generated considerable interest and study. Frequently, members of a species complex do not have complete reproductive isolation; therefore, the complex may go through extensive gene flow. In the Caribbean Sea, some encrusting and excavating sponges of the genus Cliona (Porifera, Hadromerida, Clionaidae) are grouped within the great “ Cliona viridis ” complex because of their morphological similarities. This study examined the evolutionary relationships of the Caribbean members of this complex ( C. caribbaea , C. tenuis , C. aprica and C. varians ) and related taxa based on nuclear (ITS1 and ITS2) and mitochondrial (3′ end of ND6) DNA sequences. The intragenomic ITS variation and its secondary structures were evaluated using a mixed approach of Denaturing Gradient Gel Electrophoresis (DGGE), DNA sequencing and secondary structure prediction. Considerable intragenomic variation was found in all the species, with apparently functional ITS1 and ITS2 secondary structures. Despite the subtle but clear morphological differentiation in these excavating sponges, the intragenomic copies of C. caribbaea , C. tenuis and C. aprica had a polyphyletic placement in the ITS1 and ITS2 genealogies and very low divergence. Therefore, it is clear that these species constitute a species complex (herein called Ct -complex). Genetic distances within the Ct -complex revealed that an important part of the interspecific variation overlapped with intraspecific variation, suggesting either incomplete lineage sorting or extensive gene flow. In contrast, C. varians and an unidentified “ Pione ” species emerged as monophyletic clades, being the closest sister groups to the Ct -complex. Additionally, our results support that C. laticavicola and C. delitrix conform a monophyletic group, but absence of reciprocal monophyly in these species suggests they may be life stages or ecophenotypes of a single species or they have diverged recently. Our work showed that the 3′ end of the ND6 mitochondrial gene was highly conserved and not suitable for phylogenetic analysis at the interspecific level.

The marine sponge Discodermia dissoluta is a source of the polyketide discodermolide, a potent antitumoral agent that has reached clinical trials in humans. In Santa Marta, where this species occurs at shallower depths than in other Caribbean areas, for the first time it was possible to study by SCUBA its ecological characteristics, distribution and abundance. By searching the base of the reefs (12-25 m in depth) it was found that this species is restricted to sites or bays with relatively low wave-exposure, dwelling predominantly in hard, horizontal to inclined substrata, generally exposed to light. Censuses carried out in 4 m-radius circles in sectors where this sponge occurs showed moderate densities (about 2-5 ind/50 m2) that, although not very low, do not support its commercial exploitation toobtain discodermolide. By locating individuals in the sampling space and using the point pattern distribution functions F, G and K, it was determined that individuals of D. dissoluta are aggregated in patches at scales from decimeters to a few meters. This pattern possibly arises from short-distance larval dispersal or fragmentation, both common in sponges. Size of censused individuals was estimated as projected area from digital photos, and expressed in volume by a regression calculated from the real volume of 30 collected individuals. In the population, small individuals (

The parrotfish Sparisoma viride often grazes live coral from edges undermined by the Caribbean encrusting and excavating sponge Cliona tenuis. To test whether parrotfish biting action has an effect on the dynamics of the sponge– coral interaction, we manipulated access of parrotfishes to the sponge–coral border in two species of massive corals. When parrotfish had access to the border, C. tenuis advanced significantly more slowly into the coral Siderastrea siderea than into the coral Diploria strigosa. When fish bites were prevented, sponge spread into S. siderea was further slowed down but remained the same for D. strigosa. Additionally, a thinner layer of the outer coral skeleton was removed by bioerosion when fish were excluded, a condition more pronounced in D. strigosa than in S. siderea. Thus, the speed of sponge-spread and the extent of bioerosion by parrotfish was coral species-dependent. It is hypothesized that coral skeleton architecture is the main variable associated with such dependency. Cliona tenuis spread is slow when undermining live S. siderea owing to the coral’s compact skeleton. The coral’s smooth and hard surface promotes a wide and shallow parrotfish bite morphology, which allows the sponge to overgrow the denuded area and thus advance slightly faster. On the less compact skeleton of the brain coral, D. strigosa, sponge spread is more rapid. This coral’s rather uneven surface sustains narrower and deeper parrotfish bites which do not facilitate the already fast sponge progress. Parrotfish corallivory thus acts synergistically with C. tenuis to further harm corals whose skeletal architecture slows sponge lateral spread. In addition, C. tenuis also appears to mediate the predator–prey fish–coral interaction by attracting parrotfish biting.

The Caribbean sponge Cliona delitrix is among the strongest reef space competitors; it is able to overpower entire coral heads by undermining coral polyps. It has become abundant in reefs exposed to organic pollution, such as San Andres Island, Colombia, SW Caribbean. Forty-four sponge-colonized coral colonies were followed-up for 13 months to establish the circumstances and the speed at which this sponge advances laterally into live coral tissue and the coral tissue retreats. Cliona delitrix presence and abundance was recorded at seven stations to interpret current reef space and coral species colonization trends. The spread of C. delitrix on a coral colony was preceded by a band of dead coral a few millimeters to several centimeters wide. However, the sponge was directly responsible for coral death only when live coral tissue was within about 2 cm distance; coral death became sponge advance-independent at greater distances, being indirectly dependent on other conditions that tend to accelerate its retreat. Cliona delitrix advanced fastest into recently killed clean coral calices; however, sponge spread slowed down when these became colonized by algae. The lateral advance of C. delitrix was slower than other Cliona spp. encrusting excavating sponges, probably owing to the greater depth of its excavation into the substratum. Cliona delitrix prefers elevated portions of massive corals, apparently settling on recently dead areas. It currently inhabits 6–9% of colonies in reefs bordering San Andres. It was found more frequently in Siderastrea siderea (the most abundant local massive coral), which is apparently more susceptible to tissue mortality than other corals. Current massive coral mortality caused by C. delitrix could initially change the relative proportions of coral species and in the long-term favor foliose and branching corals.

The fatty acid composition of whole phospholipids from marine sponges collected from the Colombian Caribbean Sea was determined as part of our studies on the order Halichondrida: Halichondria magniconulosa , Halichondria lutea, Petromica ciocalyptoides, Axinyssa ambrosia, Didiscus oxeata and Dragmaxia undata . Structure elucidation was accomplished by means of gas chromatography retention parameters and GCMS. Eight new fatty acids were identified by their methyl esters and N-acylpyrrolidide derivatives (i.e. 5-methyl-6-octadecenoic, 16-methyl-11-heptadecenoic, 8-methyl-4-tetracosenoic, 8,17-dimethyl-5-octadecenoic, 23-methyl-8-tetracosenoic, 20-methyl-18-tetracosenoic, 4,17-tetracosadienoic and 22,27-dimethyl-5,9-octacosadienoic acids). These findings establish alternative fatty acid biosynthetic possibilities for these organisms.

The sponge Discodermia dissoluta is the source of the potent antimitotic compound (+)-discodermolide. The relatively abundant and shallow populations of this sponge in Santa Marta, Colombia, allow for studies to evaluate the natural and biotechnological supply options of (+)-discodermolide. In this work, an RP-HPLC-UV methodology for the quantification of (+)-discodermolide from sponge samples was tested and validated. Our protocol for extracting this compound from the sponge included lyophilization, exhaustive methanol extraction, partitioning using water and dichloromethane, purification of the organic fraction in RP-18 cartridges and then finally retrieving the (+)-discodermolide in the methanol-water (80:20 v/v) fraction. This fraction was injected into an HPLC system with an Xterra RP-18 column and a detection wavelength of 235 nm. The calibration curve was linear, making it possible to calculate the LODs and quantification in these experiments. The intra-day and inter-day precision showed relative standard deviations lower than 5%. The accuracy, determined as the percentage recovery, was 99.4%. Nine samples of the sponge from the Bahamas, Bonaire, Curacao and Santa Marta had concentrations of (+)-discodermolide ranging from 5.3 to 29.3 microg/g(-1) of wet sponge. This methodology is quick and simple, allowing for the quantification in sponges from natural environments, in situ cultures or dissociated cells.

The Caribbean encrusting and excavating sponge Cliona tenuis successfully competes for space with reef corals by undermining, killing, and displacing live coral tissue at rates of up to 20 cm per year. The crude extract from this sponge, along with the more polar partitions, kills coral tissue and lowers the photosynthetic potential of coral zooxanthellae. We used a bioassay-guided fractionation of the extract to identify the compound(s) responsible. The crude extract, the aqueous partition, and compound 1, herein named clionapyrrolidine A [(-)-(5S)-2-imino-1-methylpyrrolidine-5-carboxylic acid], when incorporated into gels at close to natural volumetric concentrations, killed coral tissue when brought into forced contact with live coral for periods of 1-4 days. This is the first report of a pure chemical produced by a sponge that kills coral tissue upon direct contact. The results are consistent with the localized coral death that occurs when C. tenuis-colonized coral fragments are thrown forcibly against live coral during storms. However, healed C. tenuis fragments placed directly onto live coral were killed readily by coral defenses, and fragments placed in close proximity to coral did not have any effect on the adjacent coral tissue. Solutions of clionapyrrolidine A in sea water were only slightly toxic against live coral. Hence, the coral death naturally brought about by C. tenuis when undermining live coral does not occur through external release of allelochemicals; below-polyp mechanisms must be explored further. N-acetylhomoagmatine (2), originally isolated from Cliona celata from the Northeastern Atlantic, was also assayed for comparison purposes because of its structural similarity to siphonodictidine, a toxic compound produced by a coral excavating sponge of the genus Aka. The lack of activity of N-acetylhomoagmatine at close to natural concentrations seems to indicate that the guanidine moiety, which is also present in siphonodictidine, is not a sufficiently strong structural motif for activity against corals.

This study evaluates the biological activity and possible deterrance played by organic crude extracts from six Phaeophyta and two Rhodophyta algae from Southern Caribbean. Bioessays were carried out using concentrations equivalent to those present in algae tissue. Species in general did not show high citotoxic activity. However Dictyota pulchella, showed a delay in the mitotic process for cells stage XVI. Extracts from Dictyota bartayresiana, D. pulchella, Sargassum cymosum and Cladophyllum schnetteri, inhibited S. partitus feeding under laboratory conditions. Nontheless, only extracts from D. bartayresiana and C. schnetteri showed this activity in the field.

The icthyotoxic, cytotoxic and antimicrobial activities of aqueous, ethanol and chloroform extracts of 11 sponges from the Santa Marta region, Colombian Caribbean, were assayed. All studied sponges showed antimicrobial activity; 6 were ichthyotoxic and 7 were cytotoxic. Ircinia campana, Verongula rígida, Agelas conifera and Didiscus oxeata, were found to have activity in all three kinds of tests.

Temperaturas del agua de mar por encima del promedio durante 2005 en el Archipiélago de las Islas del Rosario (Caribe Colombiano) causaron un blanqueamiento coralino masivo en aguas someras (hasta 2-3 m de profundidad). Para confirmar resultados previos en los que el estrés inducido por calentamiento del agua en los corales puede acelerar la velocidad a la que esponjas excavadoras incrustantes le ganan espacio a los corales vivos, se contrastaron las tasas de propagación lateral en individuos de la esponja Cliona tenuis previamente marcados, que estaban colonizando los corales Diploria strigosa y Siderastrea siderea a profundidades de 5 - 6 m. Se hicieron comparaciones pareadas del avance de cada individuo de esponja entre dos intervalos de medida aproximadamente semestrales para dos períodos: junio 2001-julio 2002, que no tuvo un calentamiento inusual, y agosto 2004-septiembre 2005, con el calentamiento significativo sobre el umbral de blanqueamiento de corales, iniciado en junio 2005. Contrario a lo esperado, los datos no mostraron una influencia consistente del incremento de temperatura en la interacción esponja-coral durante el episodio de calentamiento. Las tasas de avance de C. tenuis contra S. siderea permanecieron bastante constantes, y fueron algo variables contra D. strigosa. La ocurrencia o no de cambios en el color de las colonias de coral (palidez, blanqueamiento) tampoco estuvo asociada con tasas de avance de C. tenuis consistentemente mayores o menores. Aunque es posible que un efecto generalizado de este fuerte calentamiento se rezagara hasta después de nuestro último intervalo de medida, los datos sugieren además que existe una susceptibilidad diferencial al calentamiento excesivo entre las especies y las colonias de coral y quizás entre los individuos de esponja.

From available data from four sampling stations at Ciénaga Grande de Santa Marta coastal lagoon (Colombian Caribbean), contemporary and time-lagged cross-correlations between biweekly series of "biological" variables (chrolophyll a, primary productivity) and "physical-chemical" variables (salinity, transparency, inorganic nutrientes, total nitrogen and phosphorous, phaeopigments, seston proteins) were explored. In contrast with the original analyses, turning series stationary (constant mean and variance) eliminated variations in trend and magnitude associated with climate, and emphasized variation at the scale of weeks. As a result, changes in primary production were not related either with contemporary changes in phytoplankton biomass (measured as chlorophyll a) or with previous or contemporary changes in physical chemical variables. This apparent lack of effect of the inorganic nutrients regime on the primary production may occur because nutrient availability is the dinamyc result of uptake and recycling. Only, increases in total nitrogen were associated with rises in primary production 4 weeks later, possibly from lagged used of reserves by phytoplankton. Variations in phytoplankton biomass were positively correlated with contemporary changes in dissolved phosphorous, and negatively with changes in transparency. The first relation could be caused by phosphorous liberation from the benthos in nocturnal anoxic conditions during massive blooms. The second may occur because the main agent conditioning water transparency is phytoplankton. In contrast, increases in primary production were followed by decreases in dissolved nitrogen and phosphorous two weeks later, again possibly in relation to phytoplankton generation times and the dynamics of uptake and recycling.

The Caribbean encrusting and excavating sponges Cliona aprica, C. caribbaea, C. delitrix and C. tenuis (Porifera, Hadromerida, Clionaidae), aggresively undermine and displace live coral tissue. At San Andrés island and Islas del Rosario (Colombian Caribbean), in all 145 observed cases of direct contact of the sponges C. aprica, C. caribbaea and C. tenuis with 17 coral species, corals showed unhealthy signs in their tissue. It was also noticed that the surface of these sponges is colonized by few organisms and that they are rarely preyed upon. To establish the possible use of chemical substances by these sponges in competition for space with corals (allelopathy), as inhibitors of larval settlement (antifouling), and as feeding deterrents against generalist fish (antipredatory), the activity of crude organic extracts was experimentally evaluated. Extracts were prepared in methanol and 1:2 metanol:dichloromethane and incorporated in experimental media at the natural concentration within the sponges. Using an unpublished method being developed by J. Pawlik (University of North Caroline at Wilmington) and M. Ilan (Tel Aviv University), PhytagelTM disks with crude extracts of each of the four sponge species, placed on the coral Montastrea cavernosa, produced a greater degree of polyp mortality than control gels without extract. Gels with extracts of the sponges C. aprica and C. caribbaea + C. tenuis, served in Petri dishes and used as substratum in the field, inhibited significantly the settlement of fouling organisms, in comparison to control gels. In laboratory trials, wheat flour pellets with extracts C. delitrix and C. caribbaea + C. tenuis were significantly rejected by the omnivore reef damselfish, Stegastes partitus, whereas pellets with extract of C. aprica did not deter feeding. These results suggest that substances present in the crude organic extracts of these sponges may be responsible in part for their ability to compete for reef substrata and to defend themselves from potential aggressors.

Variation in the taxonomlc and trophic structure of the zooplankton community, associated to fertilizations alternating between continental runoff and coastal upwelhng. were studied in the nenttc province of the Santa Maria area. Colombian Caribbean Sea. Sampling was carried out In November 1991 during the major rainy season, and in April 1992 during the dry season. Organisms were Identified, counted and trophically placed, and the biomass por trophic levo! was dotorminod. Eighty-two spocies-taxa were discriminated, most ot them oceaniccoastal and predominantly omnrvores. Community composition varied temporally and spatially with predominant oceanographic conditions, evidoncmg succossional procossos rotatod to fertilization pulses. During continental runoff conditions, typical of the rainy season, community composition and total biomass and abundance were spatially more heterogeneous, with species more coastal and neritic, large omnivores and detritivores and small carnívoros. Dunng upwellmg conditions, which occur as localizod pulses during the rainy season, and generalize throughout the study area during the dry season, the community was spatially more homogeneous, with spocies more ocoanic and doop-dwolhng and. in its maximum development, with higher biomasses. omnivores and detritivores small, and greater representation and size of macrofiltering herbivores and carnivores.

Ophiuroids are conspicuous dwellers of exposed and cryptic microhabitats available in coral reefs. This investigation pretended to discern ophiuroid community composition at microhabitats available in sponges and other reef components of different character (biotic v s. abiotic) or position over the substrate (elevated v s. non-elevated), at shallow reefs within the Montastraea spp. zone at San Bernardo Archipelago (Colombian Caribbean). Evaluating the abundance of organisms related to availability of different microhabitats, schemes of exclusive or preferential occupation of a particular elevated component were determined. These schemes, are discussed as initial cues that suggest the existence of benefic ecological relations. Samplings were performed at three stations. Four 20 meter transects were surveyed on each station, three during daytime and one during night. Presence and abundance of ophiuroids and microhabitat availability (area or volume) were quantified v i s u a l l y. Eleven types of microhabitats were identified. Vertical microhabitats and specially sponges and octocorals, were the most common substrate components at the study area. The ophiuroid community was composed by 22 morphotypes. Only Ophiopsila sp. 1 (with excavating habits) was restricted to one particular kind of substrate. Many other species did not use restrictedly any particular type of microhabitat, but used exclusively structures of particular characteristics (elevation, character or cripticity). T h e occupation of inferior surfaces of non-elevated components was determined by ophiuroid’s necessity of reaching cryptic conditions, and this necessity was linked to photosensitive species, or those especially vulnerable to predators, and to its consequent seek of protection. Elevated components and particularly 13 sponge species were characteristically occupied by Ophiothrix angulata - O. orstedii complex and by O . s u e n s o n i i. Sponges with different morphologies are discussed to bring differential advantages to dwelling ophiuroid species. It is suggested that a probable benefic ecologic relationship (not obligated) exists between these brittle-star species and some of the most frequently occupied sponge species. Nevertheless this must be appropriately tested by experimental work.

During the exploration of the soft calcareous bottoms of the continental shelf of La Guajira Department, 47 different species of sponges were identified in the classes Demospongiae and Calcarea. From bottom trawling carried out throughout the continental shelf on the bathymetric fringes of 10 and 50 m, it was found that the number of species is larger at 50 m depth, mainly in areas to the north and south where sand and mud sediments prevail. However, the patterns are not consistent in all the cases, owing to the low similarities between stations, based on the presence-absence of sponges, indicating a rather heterogeneous faunal composition. The soft bottoms allow the growth of non-sessile and sessile sponges; collected species show massive, incrusting ramified and spherical growth, all loosely attached but agglutinating large substratum fragments to which they hold.

The marine sponge Discodermia dissoluta is a source of the polyketide discodermolide, a potent antitumoral agent that has reached clinical trials in humans. In Santa Marta, where this species occurs at shallower depths than in other Caribbean areas, for the first time it was possible to study by SCUBA its ecological characteristics, distribution and abundance. By searching the base of the reefs (12-25 m in depth) it was found that this species is restricted to sites or bays with relatively low wave-exposure, dwelling predominantly in hard, horizontal to inclined substrata, generally exposed to light. Censuses carried out in 4 m-radius circles in sectors where this sponge occurs showed moderate densities (about 2-5 ind/50 m2) that, although not very low, do not support its commercial exploitation to obtain discodermolide. By locating individuals in the sampling space and using the point pattern distribution functions F, G and K, it was determined that individuals of D. dissoluta are aggregated in patches at scales from decimeters to a few meters. This pattern possibly arises from short-distance larval dispersal or fragmentation, both common in sponges. Size of censused individuals was estimated as projected area from digital photos, and expressed in volume by a regression calculated from the real volume of 30 collected individuals. In the population, small individuals (

The determination of antimitotic activity of organic extracts from marine organisms generates expectations on the isolation of substances with potential anticancer activity. The antimitotic activity of crude organic extracts from 15 marine sponges from the Colombian Caribbean coast were tested in vitro against embryos of the sea urchin Lytechinus variegatus. 80% of the species evaluated (Spirastrella coccinea, Myrmekioderma rea, Iotrochota imminuta, Halichondria sp., Petromica ciocalyptoides, Cinachyrella kuekenthali, Biemna cribaria, Oceanapia peltata, Xestospongia proxima, Oceanapia bartschi, Polymastia tenax y Dragmacidon reticulata) showed significant levels of inhibiting activity on the mitotic divisions at the first cellular phase of fertilized eggs. The extracts from Halichondria sp., P. ciocalyptoides and Xestospongia proxima disintegrate the cellular nuclei instantly. Extracts from Cribrochalina infundibulum showed an intermediate level of activity, while extracts from Desmapsamma anchorata and Myrmekioderma gyroderma showed no activity.

En ambientes litorales tropicales, el material organico en suspension favorece la presencia de organismos sesiles filtradores, como las esponjas, sobre los predominantemente fototroficos como las algas y los corales. En el area de Santa Marta, Caribe colombiano, la productividad se incrementa por pulsos alternantes de afloramiento costero y descarga continental, resultando en una importante diversidad y abundancia de esponjas. Las especies del genero Ircinia (I. campana, I. felix e I. strobilina) son conspicuas y abundantes en los biotopos rocoso-coralinos del area. Para establecer la influencia de las condiciones ambientales predominantes sobre la distribucion de las tres especies, sus densidades, tallas, preferencia de microhabitat, forma, color, y presencia de signos de depredacion, epibiontes e interacciones agresivas con los vecinos, se compararon en profundidad (5-20 m) entre dos localidades contrastantes por sus regimenes de turbidez y turbulencia. Al igual que en otras areas del Caribe, el orden de abundancia general fue Ircinia felix>I. strobilina>I. campana, lo cual indica diferencias intrinsecas en sus estrategias e historias de vida. En relacion aparente con la cantidad de materia organica en suspension, fuente principal de alimento de estas especies, se encontro que la densidad y el tamano de los individuos de Ircinia fueron significativamente mayores en la localidad de aguas turbias y relativamente calmadas, en comparacion con la localidad de aguas mas claras y mayor turbulencia; la densidad fue tambien mayor en aguas someras y medias en la localidad de mayor turbidez. En relacion con el efecto que ejercen las fuerzas hidrodinamicas sobre la forma de los organismos sesiles, las formas bajas preponderaron a todas las profundidades en la localidad mas turbulenta, y fueron proporcionalmente mas frecuentes en aguas someras que en aguas profundas en la localidad mas calmada, lo cual quizas se debe a la ocurrencia esporadica de fuertes mares de leva en el area. En estas especies la intensidad del color decrecio con la disminucion de la luz (con la profundidad y comparando microhabitats expuestos y cripticos). La menor penetracion de luz en la localidad con la mayor turbidez tambien implico una ligeramente mayor proporcion de individuos de colores claros en aguas someras. En las dos localidades, estas especies se encuentran preferentemente en posicion expuesta a la luz y sobre sustrato duro, aunque I. strobilina puede encontrarse frecuentemente anclada en cascajo. Los signos de depredacion y la epibiosis fueron raros, en correlacion con las defensas quimicas ya conocidas. Aunque en el muestreo no se detectaron casos claros de competencia por espacio, en el area de estudio estas especies pueden recubrir parcialmente tejido coralino.

The North-West of Urabá Gulf in the Southern Caribbean supports a variety of coral reef zones in conditions of high turbulence and fluctuating turbidity and salinity. Sponge composition and density were surveyed and their relationship with physical and structural features of the reef zones were analyzed. In total, 65 demosponges and 1 calcareous sponge species were encountered along belt transects (20 m2) on 11 stations between 1 and 17 m in depth. Sponge density in Urabá tended to be higher than in other areas with water conditions optimal for coral reef development (i.e. Roncador, Serrana and Quitasueño remote oceanic atolls in the SW Caribbean, Colombia) due possibly to higher concentrations of organic suspended materials discharged from rivers. Nevertheless, this effect was not reflected in the Urabá‘s species richness as just a limited number of species (Niphates erecta, Iotrochota birotulata and Mycale laevis) had high densities. Multivariate analyses showed that sponge community composition varies along a depth gradient and across habitats (coral and geomorphological zones), similar to the patterns observed in other Caribbean areas. However, marked taxonomic differences between shallow (6 m) zones and the great increase of the sponge density below just 6 m, seem to be a unique feature of Urabá. The absence of many species and the low abundance of sponges in shallow zones (< 6 m) may be due, not only to the variables associated to low depth, like turbulence, which is periodically very strong, but also to great fluctuations in surface salinity due to discharges of the Atrato and other local rivers. The shallow and deep stations that had low sponge richness and density, showed the greatest urchin densities (especially Echinometra viridis); therefore, it is possible that these urchins may be playing an additional controlling role on sponge populations.