Taxonomic composition and substrate affinity of conspicuous marine macroalgae of the Parque Nacional Arrecifes de Cozumel, Quintana Roo, Mexico

Antecedentes y Objetivos: Los arrecifes del Parque Nacional Arrecifes de Cozumel constituyen una de las principales formaciones arrecifales de México. Sin embargo, actualmente, son prácticamente inexistentes los estudios ficoflorísticos que permiten detectar cambios en la composición ficoflorística o su afinidad por algún sustrato. Por lo tanto, nuestro objetivo fue determinar la composición taxonómica de macroalgas marinas presentes en el Parque Nacional Arrecifes de Cozumel, así como realizar sus descripciones morfológicas y análisis de afinidad con el sustrato que colonizan. Métodos: Los muestreos se realizaron en octubre y noviembre de 2018 en 14 arrecifes del Parque Nacional Arrecifes de Cozumel, mediante buceo autónomo. Se realizaron observaciones morfo-anatómicas utilizando tanto microscopios ópticos como estereoscópicos. La determinación taxonómica se realizó a partir de literatura especializada. Resultados clave: Se determinaron 42 taxa: cinco Ochrophyta, 12 Rhodophyta y 25 Chlorophyta. La familia mejor representada para Ochrophyta fue Dictyotaceae; para Rhodophyta, Ceramiaceae y Rhodomelaceae; y para Chlorophyta, Halimedaceae. Se describen nuevos registros para el Parque Nacional Arrecifes de Cozumel incluyendo a Lobophora guadeloupensis como nuevo registro para México. Adicionalmente, se identificaron cuatro diferentes sustratos para las algas: psamofítico (33%), epilítico (32%), epizoico (19%) y epífito (16%). Los arrecifes más diversos fueron La Francesa (LF) y Santa Rosa (SR), y los menos diversos fueron Chankanaab (CK) y Tormentos (TM). Conclusiones: Aunque muchos de los registros previos en el área fueron confirmados en el presente estudio, la presencia de 18 nuevos registros reveló, por un lado, la falta de monitoreos constantes de la riqueza algal de la región, y, por otro lado, la necesidad de contar con descripciones morfológicas o referencias fotográficas que permitan contrastar los registros previos con los actuales. Dada la importancia del Parque Nacional Arrecifes de Cozumel, nuestros resultados, además de ofrecer información actualizada, representan un punto de partida para estudios en biología de la conservación.Background and Aims: The reefs of the Parque Nacional Arrecifes de Cozumel constitute one of the main reef formations in Mexico. However, up to date phycofloristic studies that allow detecting changes in the phycofloristic composition or its affinity for some substrates are practically non-existent. Our aim was to determine the taxonomic composition of marine macroalgae present in the Parque Nacional Arrecifes de Cozumel, as well as realize their morphological descriptions and an analysis of their affinity with the substrate they colonize. Methods: The sampling was carried out in October and November 2018 by autonomous diving in 14 reefs of the Parque Nacional Arrecifes de Cozumel. Morphological observations were made using optical and stereoscopic microscopes. The taxonomic determination was made using specialized literature. Key results: Fourty-two taxa were determined: five Ochrophyta, 12 Rhodophyta and 25 Chlorophyta. The best-represented family for Ochrophyta was Dictyotaceae; for Rhodophyta, Ceramiaceae and Rhodomelaceae; and for Chlorophyta, Halimedaceae. New records for the Parque Nacional Arrecifes de Cozumel are described, including Lobophora guadeloupensis as a new record for Mexico. Additionally, four different substrates for the algae were identified: psammophytic (33%), epilithic (32%), epizoic (19%) and epiphytic (16%). The most diverse reefs were La Francesa (LF) and Santa Rosa (SR), whereas the least diverse were Chankanaab (CK) and Tormentos (TM). Conclusions: Although many of the previous records in the area were confirmed in the present study, the presence of 18 new records revealed, on the one hand, the lack of constant monitoring of the algal richness of the region, and on the other hand, the need for morphological descriptions or photographic references that allow contrasting the previous records with the current ones. Given the importance of the Parque Nacional Arrecifes de Cozumel, our results, in addition to offering updated information, represent a starting point for studies in conservation biology

Contenido de carbono orgánico y características texturales de los sedimentos del sistema costero lagunar Chantuto-Panzacola, Chiapas

Seasonal and spatial distribution of surface sediments from the Chantuto-Panzacola coastal lagoon system were analyzed, including organic carbon (O.C.) content, during the years 1997 to 2003. Surface sediments were taken from 10 sites by means of a small van Veen grab sampler (3L) and sediment composition (sand, silt and clay components) was obtained by pipette analysis. There were differences in the sediments O.C. inbetween dry and wet seasons, with higher levels corresponding to the latter and showing that O.C. contributions to the system come from autochthonous and allochthonous sources through fluvial drainage. O.C. levels throughout the lagoons were highest in stations 4 (Chantuto), 5 and 6 (Panzacola), while station 1 (the entrance, influenced by marine conditions) showed lower values. Sediment texture values were markedly heterogenous throughout years, seasons and stations. The effect of tropical storm Javier was found to be significant in incrementing the sand content in almost the entirety of the system, as well as decreasing the O.C. contents. The 2003 O.C. values were similar to those measured in 1997; on the other hand, continuous change in grain size has been the norm, affecting mainly those areas where dredging activities have taken place since 2001.En este estudio se analizó la distribución textural estacional y espacial de los sedimentos superficiales y el contenido de carbono orgánico (C.O.) en ellos en el sistema costero Chantuto-Panzacola durante el período de 1997 a 2003. Los sedimentos superficiales se colectaron en 10 estaciones de muestreo con una draga tipo van Veen (3L). Se determinó el carbono orgánico (C.O.%) y se analizó la distribución textural (arena, limo, arcilla) con el método del pipeteo. Hubo diferencias significativas de C.O. en los sedimentos entre las estaciones de secas y de lluvias. El contenido de C.O. fue mayor en los meses asociados a la época de lluvias, mostrando que el aporte de C.O. proviene de fuentes tanto autóctonas, como alóctonas (por medio de la descarga fluvial). La distribución espacial de C.O. a través de las lagunas fue mayor principalmente en la E4 (Chantuto) - E6 - E5 (Panzacola), mientras que en la E1 (en la boca con influencia marina) fue mucho menor debido al flujo de agua de mar que mantiene en suspensión la materia particulada. La distribución del tamaño de grano fue muy heterogénea entre años, épocas climáticas y estaciones en las lagunas ya que varió de limo-arenoso y arena-limo-arcilloso a arcilla-arenosa. El efecto de la tormenta tropical Javier de septiembre de 1998 fue significativo, con un incremento en la proporción de arenas y disminución del C.O. en casi todo el sistema lagunar. Para el año 2003, el porcentaje de C.O. fue similar al de 1997, sin embargo, la granulometría continúa modificándose, sobre todo en las áreas donde se han realizado dragados desde el año 2001

Consideraciones batimétricas del sistema lagunar Carretas-Pereyra, Chiapas, México

The depth of the Carretas-Pereyra lagoon system was monitorei by a ruler in five stations during the period between the year 1998 to 2003. The results showed a severe varation of the depth for the year 1998 caused by high pluvial precipitations ocurred in september 1998 that produced a refill of the Pereyra and Bobo Lagoon, and a depth increment to 2 m approximately for Carretas lagoon´s mouth and 1.80 m for Bobo lagoon. Between the years 2000 and 2001, the lagoon system showed a paulatine decrease of the depth up to less than 50 cm as a results of lower precipitations with movements of sediments inside the lagoon. From the year 2002 to 2003, it established again a cyclic behaviour of the lagoon´s depth with near one meter of depth during the rainy season and half of a meter in dry season.La profundidad del sistema lagunar Carretas-Pereyra fue monitoreada por medio de una regleta, en cinco estaciones durante el período comprendido del año 1998 al año 2003. Los resultados mostraron una variación de la profundidad para el año de 1998 debido a las altas precipitaciones acaecidas en septiembre de ese año, las cuales produjeron un azolve de la laguna de Pereyra y un incremento de profundidad de cerca de los 2 m para la boca de la Laguna de Carretas y 1.80 m para Laguna del Bobo. Entre el año 2000 y 2001 se observó un decremento paulatino de la profundidad en el sistema, hasta valores menores a 50 cm como producto de años de baja precipitación con posibles movimientos de sedimentos de la laguna. A partir del 2002 y 2003 se estableció un comportamiento cíclico de la profundidad de las lagunas, cambiando la profundidad cerca de un metro en la época de lluvias y de medio metro en época de secas aproximadamente

Diversity of archaea in tropical and subtropical estuarine-lagoon ecosystems. A synthesis: Archaea in tropical coastal ecosystems

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 changeBackground. 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 chang