Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Background. There are few studies of the effect of Sargassum sp. drift on coastal ecosystems. One of the most obvious changes is the increase in turbidity, however it has been only a few studies of how this is affecting seagrass communities and what changes they can induce in them that can indicate their impact in the ecosystem. Objectives. Determine the relationship between the turbidity caused by the Sargassum drift and the morphological variation and cover percentage of Syringodium filiforme, at the reef lagoon of the area of El Castillo, Xcalak, Quintana Roo. Methods. Five consecutive 50 m transects were placed perpendicular to the coast. In each transect, 25 x 25 cm quadrants every 10 m were used to obtain cover and morphometric data. Percentage of transparency was estimated. Samples from quadrants, were identified and measured. Significant differences between transparency and plant longitude were tested through nonparametric ANOVA, Kruskal-Wallis test and a simple linear regression analysis used to determine a possible significant correlation between this two parameters. Results. At 40% transparency, monospecific meadows were found, as well as larger sizes (58.9 cm) of S. filiforme, while in the areas with greater transparency, specimens with shorter lengths and mixed with Thalassia testudinum were found. Analyzes show a negative direct relationship between turbidity and Syringodium length. Conclusions. The existence of a negative direct relationship between the atypical elongation of the canopy and the transparency, with monospecific meadows, show that, a change exist in the seagrass meadows of the reef lagoon. We consider also necessary to investigate other factors that could be also causing this variation.

Background. Water pollution by nitrate and antibiotics has been growing over the years, so the denitrifying process can be a good alternative for the simultaneous removal of both compounds. Objective. Show the role of denitrification in the elimination of antibiotics, as well as their effects on the physiology and kinetics of the respiratory process, genes, and denitrifying microbial populations. Results. There are studies on the elimination of different antibiotics under denitrifying conditions, however, in most of them, the fate of the carbonated and nitrogenous matter consumed is unknown. Antibiotics such as sulfonamides and tetracyclines cause negative effects on the denitrifying process by decreasing the nitrate removal efficiency, its rate of consumption, and promoting the accumulation of nitrite. Denitrifying genera such as Thauera and Pseudomonas were reported as resistant and/or tolerant to the presence of different antibiotics belonging to fluoroquinolones, macrolides, tetracyclines, and β-lactams, as well as mixtures of antibiotics. Decreased abundance and gene expression of genes involved in denitrification such as nirS and nosZ, was observed in the presence of sulfonamides, this effect could cause nitrite and nitrous oxide accumulation, producing a possible bottleneck in the denitrifying process. Antibiotic resistance genes have been detected in denitrifying microorganisms exposed to antibiotics, which could act as defense mechanisms to the presence of these compounds. Conclusions. The information contained in this review contributes to the knowledge about the denitrifying process and proposes its use to carry out more efficient and stable disposal of nitrate and antibiotics present in contaminated waters.

Background. Tropical and subtropical estuarine ecosystems are among the most productive ecosystems on the planet, their seasonal fluctuations, their permanent or ephemeral connection with the ocean and freshwater discharges, generate a high biodiversity that provides numerous ecosystem services. In these ecosystems, biodiversity research has focused on macro-organisms and less attention has been paid to prokaryotes, particularly the archaea group. Goal. Based on a bibliographic review of the Archaea Domain in estuaries, coastal lagoons and mangroves located in tropical and subtropical zones, to provide a synthesis of the factors that influence the presence and distribution of archaea in these ecosystems and the role they play in biogeochemical cycles. Methods. A search was made of the articles published with the keywords Archaea + tropical coastal ecosystems and Archaea + subtropical coastal ecosystems. Results. The analysis of the environmental sequences obtained, from molecular techniques, in studies of the diversity of prokaryotes in coastal lagoons, estuaries and tropical and subtropical mangroves, have revealed a high diversity of archaea belonging mainly to methanogens and anaerobic methanotrophs (Phyla Euryarchaeota), ammonium oxidizing archaea (Thaumarchaeota) and representatives of the Superphyllum Asgard. These groups can potentially participate in the carbon, nitrogen, and sulfur cycles, in aerobic or anaerobic conditions, with heterotrophic or autotrophic metabolisms, and their abundance and distribution are related to the physicochemical conditions of the ecosystems. Conclusions. The diversity of Archaea in tropical and subtropical coastal ecosystems is greater than previously recorded. These microorganisms play a vital role in various biogeochemical cycles as well as climate change.

Background. Hydrothermal systems are a novel source for the discovery of new antimicrobial compounds and/or metabolites with biotechnological potential. Objectives. In the present research, a bioactivity screening of microorganisms isolated from shallow hydrothermal systems with the capacity to inhibit the growth of microorganisms of interest in human, aquaculture, and industrial health was carried out. Methods. Bacteria were isolated from two hydrothermal systems located in Bahía Concepción and other in El Sargento, B.C.S. in rainy and dry season. The antimicrobial activity against human pathogens, aquaculture pathogens, and marine biofilm-forming bacteria was evaluated, using the well diffusion technique. Results. 73 % of the isolated bacteria produced substances capable of inhibiting the growth of at least one of the microorganisms evaluated. Antagonism was only observed for 15 of the 36 target bacteria, Photobacterium damselae subsp. damselae was the most sensitive, which was inhibited by 51 % of the marine bacteria. Regarding the activity by site and season of collection, a greater number of active isolates against aquaculture pathogens was observed, predominating the dry season isolates for Mapachitos and Santispac, while in El Sargento the highest number of active isolates was obtained during the rainy season. Conclusion. Marine bacteria from hydrothermal systems are able to produce antimicrobial metabolites that could be used in different areas e.g. health and industry

Background. In Mexico, the neotropical otter (Lontra longicaudis annectens, Olfers, 1818) is widely distributed, and its populations are threatened. Objectives. To estimate the density and abundance of neotropical river otters in the Alvarado Lagoon System (SLA), Veracruz. Methods. The SLA has an extension of 51,960.52 hectares and is made up of coastal lagoons, interior lagoons, and rivers. We employed the distance sampling technique with systematic transects to estimate the distribution, density, and abundance of the Neotropical otter in the SLA. Results. A total of 25 independent otter sightings were obtained; the Limón, Blanco, and Culebrilla rivers are the areas with the most significant sights. An abundance of 934 (% C.V.= 20.45) otters was estimated for the entire SLA, with a density of 0.179 organisms/km2 (% C.V.= 20.45). Conclusions. This study contributes to determining the first direct estimation of density for this species in a region of Mexico. The importance of this study is the precision with which the otter population was estimated, which allows for more robust information to make decisions and to take actions for the management and conservation of the species.

Background. Seven remora species are described for the Eastern Pacific, of them Remora brachyptera has not been confirmed in South Mexican Pacific. Goals. The aim of this note is to report the presence of R. brachyptera on the Gulf of Tehuantepec. Methods. The specimen was collected during sportfish activities in May 2013 in the Gulf of Tehuantepec, Oaxaca. Results. This species was identified by having 17 laminae in the cephalic disc and the dorsal fin that originates above the anal fin, dorsal fin with 27 rays, pectoral fin with 23 rays, cephalic disc length 32.6% standard length, and truncated tail. Conclusions. This is first record of R. brachyptera in the Gulf of Tehuantepec.

Background. Coastal communities are highly dependent on ecosystem services, but the benefits and livelihoods people derive from natural ecosystems are directly and indirectly affected by climate change. The need for a mechanistic understanding of how components of climate change translate into measurable impacts on ecosystems and society is fundamental to the ability to manage, plan and mitigate for the most likely environmental futures, yet progress in this area in tropical and subtropical countries is frustrated by a lack of research capacity at the local and regional level. Objectives. Here, we investigate the research capacity of the countries along the Pacific coast, between Mexico and Chile, a region with an extensive coastline (23,191 km) that spans 11 countries of varying socio-economic development status and anticipated to be especially vulnerable to climate change. Methods. Specifically, our focus was to explore how the effects of climate change on ecosystem services (provision, regulation and cultural) may relate to research capacity and gross domestic product (GDP) in each country along the Pacific coast of the Americas. Results. We find that, since 1980, the number of peer-reviewed scientific studies relevant to this topic strongly correlates with GDP (r = 0.90, p < 0.05) and that research effort is an order of magnitude lower along the Latin American Pacific coast (13.8 studies 1000 km-1) than in the neighbouring Californian coast (103 studies 1000 km-1). Conclusions. Our results highlight the need to better develop the research in the Latin America Pacific, and for more work on the key links between climate change and ecosystem services.

Antecedentes. La contaminación del agua por nitrato y antibióticos ha ido creciendo a lo largo de los años, por lo que el proceso desnitrificante puede ser una buena alternativa para la eliminación simultánea de ambos compuestos. Objetivo. Mostrar el papel de la desnitrificación en la eliminación de antibióticos, así como los efectos de estos compuestos sobre la fisiología y cinética del proceso respiratorio, los genes y las poblaciones microbianas desnitrificantes. Resultados. Existen estudios sobre la eliminación de diferentes antibióticos bajo condiciones desnitrificantes, sin embargo, en la mayoría de los trabajos, el destino de la materia carbonada y nitrogenada consumida se desconoce. Antibióticos como las sulfonamidas y tetraciclinas provocan efectos negativos sobre el proceso desnitrificante al disminuir la eficiencia de eliminación de nitrato, su velocidad de consumo y propiciar la acumulación de nitrito. Se reportaron géneros desnitrificantes como Thauera y Pseudomonas como resistentes y/o tolerantes ante la presencia de diferentes antibióticos pertenecientes a las fluoroquinolonas, macrólidos, tetraciclinas y β-lactámicos, así como mezclas de éstos. La disminución de la abundancia y expresión génica de genes que participan en la desnitrificación como nirS y nosZ, fue observada en presencia de sulfonamidas, efecto que podría causar la acumulación de nitrito y óxido nitroso, ocasionando un posible cuello de botella en el proceso desnitrificante. En microorganismos desnitrificantes expuestos a antibióticos han sido detectados genes de resistencia a antibióticos, los cuales podrían actuar como mecanismos de defensa ante su presencia. Conclusiones. La información contenida en la presente revisión contribuye al conocimiento sobre el proceso desnitrificante, proponiendo su uso para llevar a cabo una eliminación más eficiente y estable de nitrato y antibióticos presentes en aguas contaminadas.

Background. The spatial and temporal changes of assemblages of aquatic insect can be used to detect the anthropic impacts that influence the biological communities. Goals. We compared the assemblages of aquatic insect in 1997 and 2014 in two subtropical river drainages, the association with water characteristics, and we discuss their implications for ecosystems conservation. Methods. True diversity of the aquatic insect fauna at family level and their community structure for 27 study sites in 1997 and 2014 were assessed. Multivariate analyzes were used to compare aquatic insect assemblages and the abundance of functional feeding groups. Results. There were significant differences in the dissolved oxygen (DO) of the water between 1997 and 2014, decreasing its values. Other variables correlated to DO were also modified, with a decrease in pH and an increase in temperature. We found a correlation between reduction of DO and water pH with a decline in the overall abundance of aquatic insects; also, with shifts in the community structure, from the decrease of groups such as some Ephemeroptera and scrapers, to the increase in opportunistic families such as Chironomidae, Culicidae, and other predator families such as Coenagrionidae, Corixidae and Veliidae, and more abundance of collectors. Families such as Heptageniidae and Caenidae decreased in abundance, as well as other benthic groups. Conclusions. The assemblages of aquatic insect are useful to indicate a generalized degradation of environmental conditions across localities and time in two subtropical river drainages, related to water quality degradation symptoms such as reduction of pH levels and dissolved oxygen, usually associated with anthropogenic stressors.

Background. Coastal communities are highly dependent on ecosystem services, but the benefits and livelihoods people derive from natural ecosystems are directly and indirectly affected by climate change. The need for a mechanistic understanding of how components of climate change translate into measurable impacts on ecosystems and society is fundamental to the ability to manage, plan and mitigate for the most likely environmental futures, yet progress in this area in tropical and subtropical countries is frustrated by a lack of research capacity at the local and regional level. Objectives. Here, we investigate the research capacity of the countries along the Pacific coast, between Mexico and Chile, a region with an extensive coastline (23,191 km) that spans 11 countries of varying socio-economic development status and anticipated to be especially vulnerable to climate change. Methods. Specifically, our focus was to explore how the effects of climate change on ecosystem services (provision, regulation and cultural) may relate to research capacity and gross domestic product (GDP) in each country along the Pacific coast of the Americas. Results. We find that, since 1980, the number of peer-reviewed scientific studies relevant to this topic strongly correlates with GDP (r = 0.90, p < 0.05) and that research effort is an order of magnitude lower along the Latin American Pacific coast (13.8 studies 1000 km-1) than in the neighbouring Californian coast (103 studies 1000 km-1). Conclusions. Our results highlight the need to better develop the research in the Latin America Pacific, and for more work on the key links between climate change and ecosystem services.