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Microbial life forms are among the most ubiquitous on Earth, yet many remain understudied in Caribbean estuaries. We report on the prokaryote community composition of the Urabá Estuary in the Colombian Caribbean using 16S rRNA gene-transcript sequencing. We also assessed potential functional diversity through 38 metabolic traits inferred from 16S rRNA gene data. Water samples were collected from six sampling stations at two depths with contrasting light-penetration conditions along an approximately 100 km transect in the Gulf of Urabá in December 2019. Non-metric multidimensional scaling analysis grouped the samples into two distinct clusters along the transect and between depths. The primary variables influencing the prokaryote community composition were the sampling station, depth, salinity, and dissolved oxygen levels. Twenty percent of genera (i.e., 58 out 285) account for 95% of the differences between groups along the transect and among depths. All of the 38 metabolic traits studied showed some significant relationship with the tested environmental variables, especially salinity and except with temperature. Another non-metric multidimensional scaling analysis, based on community-weighted mean of traits, also grouped the samples in two clusters along the transect and over depth. Biodiversity facets, such as richness, evenness, and redundancy, indicated that environmental variations-stemming from river discharges-introduce an imbalance in functional diversity between surface prokaryote communities closer to the estuary's head and bottom communities closer to the ocean. Our research broadens the use of 16S rRNA gene transcripts beyond mere taxonomic assignments, furthering the field of trait-based prokaryote community ecology in transitional aquatic ecosystems.IMPORTANCEThe resilience of a dynamic ecosystem is directly tied to the ability of its microbes to navigate environmental gradients. This study delves into the changes in prokaryote community composition and functional diversity within the Urabá Estuary (Colombian Caribbean) for the first time. We integrate data from 16S rRNA gene transcripts (taxonomic and functional) with environmental variability to gain an understanding of this under-researched ecosystem using a multi-faceted macroecological framework. We found that significant shifts in prokaryote composition and in primary changes in functional diversity were influenced by physical-chemical fluctuations across the estuary's environmental gradient. Furthermore, we identified a potential disparity in functional diversity. Near-surface communities closer to the estuary's head exhibited differences compared to deeper communities situated farther away. Our research serves as a roadmap for posing new inquiries about the potential functional diversity of prokaryote communities in highly dynamic ecosystems, pushing forward the domain of multi-trait-based prokaryote community ecology.

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Introducción: Los arrecifes coralinos están entre los ecosistemas más importantes y valiosos del planeta. Sin embargo, en las últimas décadas han sufrido procesos de degradación, reduciendo su cobertura coralina y complejidad topográfica. La competencia alga-coral es un proceso ecológico importante en la dinámica de los arrecifes coralinos y estudiarla permite entender la resiliencia en estos sistemas. Objetivo: Determinar el efecto de la herbivoría sobre la competencia coral-alga bajo diferentes escenarios (empleando una combinación de enfoques descriptivos y experimentales) y dos épocas climáticas en Capurganá, Caribe colombiano (área de conservación marina, Hope Spot). Métodos: Entre julio 2018 y abril 2019, se evaluó el rol de la herbivoría, mediante un experimento de exclusión - no exclusión en 48 individuos coralinos bajo diferentes escenarios de interacción entre Siderastrea siderea y sus algas circundantes (tratamientos), la mitad de los corales juveniles se cubrieron con cajas metálicas de 2 400 cm2 fijas al bentos. Los tratamientos consistieron en: T1= Control, T2= Remoción de algas, T3= Daño coralino, T4= Juveniles en contacto con algas artificiales, T5= T2 + T3, T6= T2 + T4, T7= T3 + T4 y T8= T2 + T3 + T4. Resultados: Después de un muestreo total de nueve meses, se encontró diferencias entre escenarios con y sin exclusión (P= 0.006) y la época climática (P= 0.032), el crecimiento coralino fue mayor cuando las algas fueron removidas en presencia de herbívoros (DMS de Fisher, mean ± SE 9.871 ± 8.298) y la aparición de algas fue mayor dentro de las jaulas que fuera de ellas, mientras que el tratamiento de competencia no presentó interferencia en el crecimiento (P= 0.155). Los juveniles fueron colonizados por algas cuando su tejido fue dañado y sin herbívoros (mean ± SE 9.359 ± 3.901). Hubo diferencias en el crecimiento coralino entre épocas (época seca: Media 0.0029 ± SD 0.0243 cm2/día y época húmeda: Media 0.0022 ± SD 0.0161 cm2/día). Conclusiones: Los resultados indican que el crecimiento coralino depende de la presencia de herbívoros que regulan el crecimiento, reproducción y supervivencia de las algas; actualmente este proceso está siendo interrumpido como consecuencia de la sobrepesca en estos ecosistemas, por lo cual, es importante destacar que la reducción de la herbivoría resultó en un crecimiento más rápido de algas, demostrando la importancia crítica de la herbivoría para el resultado de la interacción competitiva. Sin embargo, algunas algas podrían ser benéficas para los juveniles coralinos cuando su abundancia es lo suficientemente grande para protegerlos de la depredación por peces y suficientemente pequeña para no reducir considerablemente su crecimiento. Estos procesos son decisivos en estos ecosistemas, particularmente en zonas donde éste es relevante desde una perspectiva ecológica, social, cultural y económica, lo cual hace que estos estudios sean importantes para la correcta implementación de manejo integrado en zonas arrecifales ayudando a la recuperación, protección y conservación del arrecife, y promoviendo la disminución de la pesca de herbívoros.

Introduction: Coral reefs are among the most important and valuable ecosystems on the world. However, in recent decades they have been under siege by degradation processes reducing their coral cover and topographic complexity. The coral-algae competition is an important ecological process in the dynamics of coral reefs thus studying is pivotal for understanding the resilience in these systems. Objective: To determine the effect of herbivory on coral-algae competition under different scenarios (using a combination of descriptive and experimental approaches) and two climatic seasons in Capurganá Bay, Colombian Caribbean, in a marine conservation area (Hope Spot). Methods: Between July 2018 and April 2019, the role of herbivory was evaluated, performing an exclusion - no exclusion experiment in 48 coral individuals under different scenarios of interaction between Siderastrea siderea and its surrounding algae (treatments), half of the juvenile corals were covered with 2 400 cm2 metal boxes fixed to the benthos. The treatments consisted of : T1= No manipulation (control), T2= Algae removal, T3= Coral damage, T4= Juveniles in contact with artificial algae, T5= T2 + T3, T6= T2 + T4, T7= T3 + T4 and T8= T2 + T3 + T4. Results: After nine months of experiments, differences were found between with and without exclusion (P= 0.006) and the climatic season (P= 0.032), it was found that coral growth was higher when algae were removed in the presence of herbivores (Fisher's LSD, mean ± SE 9.871 ± 8.298) and the appearance of algae was greater inside the cages than outside them, while the competitive treatment did not show growth interference (P= 0.155). Algae colonized juveniles when their tissue was damaged and herbivory was excluded (mean ± SE 9.359 ± 3.901). There were differences in coral growth between seasons, being higher in the dry season (Average 0.0029 ± SD 0.0243 cm2/day) than in the wet season (Average 0.0022 ± SD 0.0161 cm2/day). Conclusions: The coral growth depended on the presence of herbivores that regulate the growth, reproduction, and survival of algae; currently, this process is being interrupted as a result of overfishing in the reef ecosystems. However, some algae could be beneficial for juvenile corals when their abundance is large enough to protect them from fish predation and small enough not to significantly reduce their growth. These processes are decisive in these ecosystems, particularly in areas where it is relevant from an ecological, social, cultural and economic point of view, which makes these studies important for the correct implementation of integrated management in reef areas helping recovery, protection, and conservation of the reef promoting the decrease of herbivore fishing.

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Gulf of Urabá is considered a tourist zone of Antioquia Department attracts a large number of visitors to explore the aquatic ecosystem and beaches thus offering a large economic benefit. However, this region has been affected by various anthropogenic effects thus generating an environmental problematic that affect aquatic ecosystem. Over the years, several research has been evaluated pollutant such as pesticides, metals and physicochemical parameters, even our laboratory had found several toxic metals in fish from this same area. The presence of emerging pollutant in matrices such as seawater and fish from Gulf of Urabá have not been reported, and to the best of our knowledge, this is the first study. This work presents important aspects relating to sampling, monitoring and surveillance of seawater and several fish species caught in the area in order to determinate the content of emerging pollutant (triclosan, ibuprofen, diclofenac) using UPLC-QqQ/MS. In general, all three pharmaceuticals in different sampling sites were detected and total concentrations ranged from 0.10 to 1.54 µg/L in surface water. However, emerging pollutants content in fish muscle was not detected. In addition, a high variability in triclosan, ibuprofen and diclofenac concentrations according to the season of sampling was found. Regarding to seasonal variations, most emerging pollutant in the surface water had variation in levels both dry and wet season. Better removal was presented in the dry season, due to stronger irradiation and greater activity of microorganisms.

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Resumen Introducción: existe relación entre el aumento de una población y la presión que esta ejerce sobre el ecosistema; en este sentido, se reflexiona sobre las comunidades de pescadores que habitan el golfo de Urabá y su situación de seguridad alimentaria. Reflexión: el golfo de Urabá, con su litoral de manglar, ha alimentado a las poblaciones que de larga data han vivido en su orilla; sin embargo, la situación de desplazamiento forzado que se ha vivido en la región ha incrementado el número de pobladores de las comunidades pesqueras. La pesca se ha convertido en la fuente de alimento y sustento de antiguos y nuevos pobladores, lo que ha llevado a una sobreexplotación de los recursos marinos y al deterioro del ecosistema, que ha reducido la disponibilidad de alimento, y lleva a condiciones de inseguridad alimentaria a los habitantes de la orilla del golfo. Conclusiones: la situación de seguridad alimentaria de las comunidades de pescadores requiere ser comprendida en su contexto, en su ecosistema, en su cotidianidad; requiere también del trabajo transdisciplinario, más allá de la nutrición, y su atención necesita del diseño e implementación de alternativas concertadas de manera participativa con los pobladores.

Abstract Introduction: There is a relationship between the increase of a population and the pressure it exerts on the ecosystem. In this sense, this article reflects on the fishing communities that inhabit the Gulf of Urabá and its food security situation. Reflection: The Gulf of Urabá, with its mangrove littoral, has fed the populations that have long lived on its shore; however the situation of forced displacement experienced in the region has increased the number of inhabitants of the fishing communities. Fishing has become the source of food and sustenance for old and new settlers, which has led to over-exploitation of marine resources, deterioration of the ecosystem, reduced availability of food, and has led to food insecurity of the inhabitants of the gulf shore. Conclusions: The food security situation of the fishing communities needs to be understood in its context, its ecosystem, and daily life; it also requires transdisciplinary work, beyond nutrition, and requires attention to design and implementation of concerted alternatives for and with the villagers.

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En el sector austral del mar Caribe se desconocen los cambios ambientales holocénicos y sus implicaciones en la composición de la micro-malacofauna marina. Se realizó una expedición oceanográfica a bordo del buque ARC-Quindío de la Armada de la República de Colombia; para realizar perforaciones en tres sitios del golfo de Urabá, utilizando nucleador de gravedad en plataforma. Se estudió la composición taxonómica (materia orgánica y carbonato de calcio) y abundancia de micromoluscos; para relacionarlos con posibles cambios paleoambientales durante el holoceno tardío en el golfo. Se estableció que la alta riqueza y abundancia de los micromoluscos se da a mayor carbonato de calcio y menor materia orgánica. La abundancia y riqueza de micromoluscos dieron respuesta a cambios ambientales del Holoceno tardío. Se logró definir dos ambientes contrastantes en el golfo de Urabá durante los últimos 2800 años; un ambiente más antiguo dominado por aguas marinas y un ambiente de mezcla más reciente dominado por aguas estuarinas.

Holocene environmental changes in the southern Caribbean Sea and their implications on the composition of marine micro and malacofauna are unknown. We embarked an océanographie expedition aboard the ship, ARC-Quindío of the Colombian Navy, to drill at three sites in the Gulf of Urabá using a platform gravity corer. To find possible correlations with paleoenvironmental changes during the late Holocene in the Gulf, we assessed the taxonomic composition (organic matter and calcium carbonate) and micromollusc abundance. The elevated richness and abundance of micromolluscs yields more calcium carbonate and less organic matter and answers to environmental changes in the late Holocene. We were able to define two contrasting environments in the Gulf of Urabá during the last 2800 years; an earlier environment dominated by marine waters and a more recent environment of a mixture of waters dominated by estuarine waters.

No sector austral do mar Caribe se desconhecem as alterações ambientais holocénicas e as suas implicações na composição da micro-malacofauna marinha. Realizou-se uma expedição oceanográfica a bordo do navio ARC-Quindío da Armada da República de Colômbia; para realizar perfurações em três sítios do golfo de Urabá, utilizando nucleador de gravidade em plataforma. Estudou-se a composição taxonómica (matéria orgânica e carbonato de cálcio) e abundância de micro-moluscos; para relacioná-los com possíveis alterações paleoambientais durante o holoceno tardio no golfo. Estabeleceu-se que a alta riqueza e abundância de micro-moluscos deram resposta a alterações ambientais do Holoceno tardio. Conseguiu-se definir dois ambientes contrastantes no golfo de Urabá durante os últimos 2800 anos; um ambiente mais antigo dominado por águas marinhas e um ambiente de mistura mais recentemente dominado por águas estuarinas.

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A pesar que los manglares son reconocidos a nivel mundial como ecosistemas altamente productivos y ecológicamente importantes, en la actualidad, su extensión se ha reducido significativamente debido a las actividades humanas en las zonas costeras. Por lo tanto, es necesario investigar su dinámica y respuestas bajo el creciente y sostenido impacto del cambio climático y antropogénico. Durante dos estaciones climáticas contrastantes (sequía, lluvia) se estudió la producción de hojarasca del mangle negro Avicennia germinans L. en la bahía El Uno cerca al municipio de Turbo, noroccidente de Colombia (8º N). El aporte de materia orgánica fue separado por estructuras (hojas, ramas, flores y frutos) donde se registró un aporte significativamente mayor de hojas. La biomasa seca total durante ambas estaciones fue de 7,09±9,66 y 5,36±5,67 g m-2día-1. Los valores mínimos y máximos fueron de 0,63-8 y 0,49-3,65 g m-2día-1 durante la estación seca y lluviosa, respectivamente. Se detectaron diferencias significativas entre las estructuras orgánicas pero no entre las estaciones climáticas analizadas. Se discuten algunos impactos naturales y antropogénicos pasados y actuales, que afectan la dinámica de los manglares, al igual que la importancia de la producción de hojarasca para la productividad primaria y secundaria, en zonas altamente perturbadas del Caribe colombiano.

Although mangroves are recognized worldwide as highly productive and ecologically important ecosystems , at present its extent has been significantly reduced due to human activities in coastal areas. Therefore, it is necessary to investigate their dynamics and responses under the growing and sustained climatic and anthropogenic impacts. During two contrasting seasons (drought, rain) the fallen leaves production of the black mangrove Avicennia germinans L. was investigated at El Uno Bay, near Turbo Municipality, North-Western Colombia (8º N). Organic matter input was sorted by structure (leaves, branches, flowers, fruits) with leaves registering the highest significant values. Total dry biomass during both seasons was 7.09±9.66 and 5.36±5.67 g m-2day-1. The lowest and highest organic matter values were 0.63-8 and 0.49-3.65 g m-2day-1 during the dry and rainy season, respectively. Significant differences between organic structures but not between seasons analyzed were detected. Some relevant past and present natural and anthropogenic impacts affecting the mangroves dynamics are discussed, as well as the importance of fallen leaves input to the primary and secondary production in highly disturbed zones of the Colombian Caribbean area.

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