Abstract The demand for low-cost and time-efficient biomonitoring and ecological assessment strategies has increased due to threats to biodiversity. We evaluated the ability of surrogates (genera and biovolume classes) to access information provided by diatom species. Moreover, we investigated whether the relative importance of spatial and environment on diatom communities identified at the genus or classified at biovolume classes reflects the ecological responses at the species. We used biotic, environmental, and spatial data from Pampa streams. We employed Procrustes analysis to detect whether the spatial variation of communities at the species level was represented by the surrogates and variation partitioning to evaluate the relative importance of spatial and environment. We found high congruence between the surrogates and diatom species communities. Furthermore, whilst both spatial and environment were important to explain species composition, only the environment was important for both surrogates. We suggest that the use of genus-level determinations can provide information about the environmental relationships of species, whereas biovolume classes may be useful to detect changes in diatom communities. These results are a first step to seek for strategies aiming to simplify biological monitoring and assessments at pampean streams, especially considering the demand for the identification of organisms at the species. lowcost low cost timeefficient time efficient biodiversity genera Moreover biotic streams Furthermore composition genuslevel

Abstract Halamphora adumbratoides was described in 2018 from the Atlantic Ocean (Florida Bay, USA), the type locality of this species. In this report, we present the morphological characteristics and molecular identity of this taxon (strain CIBA 160) collected in the Gulf of California, Mexico (Pacific Ocean region). Cells of the strain CIBA 160 obtained from laboratory cultures showed morphological characteristics inconsistent with the original description, specifically the shape of the valve and the presence of pores at the end of the dorsal raphe ledge at each end of the raphe. Regarding size, the length (4.1-6.6 μm) of the CIBA 160 strain is much shorter than in the original description (10.0-18.0 μm). However, the valve width and number of striae do coincide with the ranges in that description. At the molecular level, DNA sequences of the CIBA 160 strain showed 100, 99.8, and 99.5% similarity, respectively, for SSU, rbcL, and psbC with the H. adumbratoides sequences from the Atlantic Ocean. Our study supports the first case of interoceanic distribution and the second overall recording of this species.

Resumen Halamphora adumbratoides fue descrita en 2018 en muestras procedentes del Océano Atlántico, siendo Florida Bay, USA, la localidad tipo para esta especie. En esta publicación, presentamos las características morfológicas y la identidad molecular de este taxón (cepa CIBA 160) colectado en el Golfo de California, México (en la región del Océano Pacífico). Las células de la cepa CIBA 160, fueron obtenidas mediante cultivos de laboratorio y mostró características que no corresponden con la descripción original, específicamente la forma de la valva y la presencia de poros al final de cada extremo del margen dorsal del rafe. En relación al tamaño, la longitud (4.1-6.6 μm) de la cepa CIBA 160 es menor a la de la descripción original (10.0-18.0 μm). Sin embargo, el ancho de la valva y el número de estrías coinciden con los intervalos de la descripción. A nivel molecular, las secuencias del DNA de la cepa CIBA 160 mostraron 100, 99.8, y 99.5% de similitud, respectivamente con las secuencias de SSU, rbcL, y psbC de células de H. adumbratoides originarias del Océano Atlántico. Nuestro trabajo presenta el primer registro de la distribución interoceánica y el segundo registro para esta especie desde su descripción.

Abstract Introduction: Costa Rica has hundreds of lakes, many of which have never been scientifically studied. Objective: To carry out a first, basic limnological study of Laguna Pozo Verde in Juan Castro Blanco National Park, Costa Rica (~1935m elevation), to provide baseline data for studying future changes. Methods: We measured water depths and temperatures, and Secchi depth; analyzed surface sediments; and examined maps and satellite imagery. Results: Though described by some as formed by volcanic processes, Laguna Pozo Verde likely formed in a landslide, which occur frequently in this rainy area on the steep south slope of the inactive Porvenir Volcano. Our soundings showed a maximum depth of 9,25m near the center of the lake. The water was moderately transparent (Secchi depth 2,6m), with circumneutral pH, and temperatures from 15,9-18,1°C, with weak stratification at 0,5m. Surface sediments contained 27% organic matter, and had C/N ratios and stable carbon isotope values consistent with lacustrine algae and C3 plants; Surirella angusta composed over 90% of the diatoms. Conclusion: The lake is significantly shallower than reported, and surface sediments have a diatom assemblage unique among 88 lakes examined in Costs Rica.

Resumen Introducción: Costa Rica tiene cientos de lagos, muchos nunca estudiados científicamente. Objetivo: Conocer la limnología de Laguna Pozo Verde en el Parque Nacional Juan Castro Blanco, Costa Rica (~1935m de elevación), como referencia para estudiar futuros cambios. Métodos: Medimos la profundidad y temperatura del agua y la profundidad de Secchi; analizamos sedimentos superficiales; y examinamos mapas e imágenes satelitales. Resultados: Aunque algunos la describen como formado por procesos volcánicos, es probable que Laguna Pozo Verde se haya formado en un deslizamiento de tierra, algo común en esta zona lluviosa de la empinada ladera sur del Volcán Porvenir (inactivo). Hallamos una profundidad máxima de 9,25m cerca del centro. El agua era moderadamente transparente (profundidad de Secchi 2,6m), con un pH cercano a neutral y temperaturas de 15,9-18,1°C, y una débil estratificación a 0,5m. Los sedimentos superficiales contenían un 27% de materia orgánica y tenían cocientes C/N y valores de isótopos de carbono estables, coherentes con algas lacustres y plantas C3; más del 90% de las diatomeas eran Surirella angusta. Conclusión: La laguna es significativamente más somera de lo informado y los sedimentos superficiales albergan una combinación de diatomeas única entre los 88 lagos examinados en Costa Rica.

ABSTRACT Background: Diatom assemblages in sediments are frequently used as water quality and paleoenvironmental indicators. However, sedimentary diatom assemblages may present taphonomic biases due to processes occurring in the water column and water-sediment interface. Objective: The present study aimed to determine if in tropical deep lakes, the differences between water column, sediment trap and surface sediment samplings were large enough to provide antagonistic interpretations. It also aimed to determine if diversity metrics would be statistically different between the three kinds of samples. Methods: This study was performed in Lake Alberca de Tacámbaro, Michoacan, Mexico, and involved the comparison of diatom species composition and diversity between phytoplankton, sediment trap and surface sediment samplings. Results: Nearly 80% of the diatom species, including the five most abundant taxa, were present in the three kinds of samples. Phytoplankton and sediment trap samplings documented the seasonal dynamics and indicated that the changes in species composition and diversity metrics were associated with the mixing and stratification processes of the water column. Unexpectedly, phytoplankton and sediment trap samples had relatively high percentages (ca. 20%) of benthic taxa (Achnanthidium minutissimum and Brachysira vitrea), which behaved as tychoplanktonic. Surface sediment samples showed a higher species richness and Simpson’s diversity, but the three kinds of samples had similar Shannon diversities. Conclusions: In spite of the differences between the sampling methods, they did not provide antagonistic results on the condition of the lake. Surface sediment samples showed richer and more equitable assemblages, including diatoms from different habits, with an average-time window of about two years. The discrepancies between the phytoplankton and surface sediment diatom assemblages are an indication of recent changes in the diatom flora of this lake.

RESUMEN Antecedentes: La composición de diatomeas en sedimentos es una herramienta para evaluar calidad del agua y en la reconstrucción paleoambiental. Sin embargo, puede presentar sesgos tafonómicos debido a procesos en la interfaz agua-sedimentos. Objetivo: Determinar si en lagos tropicales profundos las diferencias entre muestreos de columna de agua, sedimentos de trampas y superficiales serían lo suficientemente grandes para aportar interpretaciones contradictorias sobre la condición del ecosistema y establecer si existen diferencias significativas en las métricas de diversidad. Métodos: En la Alberca de Tacámbaro, Michoacán, México, se comparó de la composición y métricas de diversidad de diatomeas en muestras provenientes de los tres tipos de muestreo. Resultados: Casi el 80% de las especies, incluyendo las cinco más abundantes, estuvieron presentes en los tres tipos de muestreo. El fitoplancton y trampas de sedimentos documentaron la dinámica estacional, con cambios asociados con la mezcla y estratificación de la columna de agua. Las muestras de fitoplancton y de trampas de sedimento tuvieron un porcentaje elevado (~20%) de especies de bentónicas (Achnanthidium minutissimum y Brachysira vitrea), que se comportan como ticoplanctónicas. Los sedimentos superficiales mostraron una mayor riqueza de especies y diversidad de Simpson, los tres métodos tuvieron valores similares de diversidad de Shannon. Conclusiones: Los tres tipos de muestreo no aportaron interpretaciones antagonistas sobre la condición del lago. Los sedimentos superficiales mostraron una riqueza de especies mayor y más equitativa con diatomeas de varios hábitos y zonas del lago, integrando una ventana de tiempo promedio de aproximadamente dos años. Las discrepancias entre las muestras del fitoplancton y los sedimentos superficiales parecen ser una indicación de cambios recientes en la flora de diatomeas de este lago.

Resumen Antecedentes: El patrón evolutivo de las dinofitas es complejo y requiere estudios taxonómicos exhaustivos, en desarrollo y morfología, ecología, evolución y genética de las especies. Preguntas: ¿Qué tan reciente fue la transición de D. baltica de México hacia agua dulce con base en la filogenia calibrada temporalmente de las Kryptoperidiniaceae? Especies estudiadas y descripción de los datos: Durinskia baltica, Kryptoperidiniaceae y el registro fósil conocido de dinotomos (dinofitas con diatomeas endosimbiontes) Sitios y años de estudio: Xochimilco, Ciudad de México. 2010 a 2019. Métodos: Se usaron inferencias bayesianas y secuencias de hospederos calibradas con un método de reloj relajado para generar las filogenias. Resultados: Se obtuvieron secuencias genéticas del sector 18S rDNA en el hospedero y del sector rbcL en el endosimbionte. El endosimbionte es genéticamente distinto de otros endosimbiontes con el mismo tipo de diatomea. En cambio, considerando las especies de agua dulce conocidas de Durinskia, la relación genética entre hospedadores es robusta y de origen reciente. La antigüedad de la secuencia mexicana coincide con el origen geológico de la cuenca de Xochimilco, sugiriendo particularidades en la historia evolutiva de los dinotomos ligadas a las regiones geográficas que habitan. Conclusiones: Nuestro escenario evolutivo con una filogenia calibrada indica que la transición de Durinskia baltica hacia agua dulce en la cuenca de Xochimilco está geológicamente contextualizada. El cambio ambiental histórico del lago de Xochimilco con respecto a la salinidad corresponde con una colonización inicial de D. baltica en un ambiente salobre y su posterior adaptación al agua dulce.

Abstract Background: The evolutionary pattern of dinophytes is complex and requires comprehensive taxonomic studies addressing the species' development and morphology, ecology, evolution, and genetics. Questions: How recent was the transition of D. baltica from Mexico to freshwater based on a calibrated phylogeny tree of the Kryptoperidiniaceae? Studied species and data description: Durinskia baltica, Kryptoperidiniaceae and the known fossil record of dinotoms (endosymbiont diatom-host dinophytes). Study sites and dates: Xochimilco, Mexico City. 2010 to 2019. Methods: Phylogenies were constructed with Bayesian inferences and host sequences were calibrated with a relaxed clock method. Results: We obtained genetic sequences of the 18S rDNA sector in the host and the rbcL sector in the endosymbiont. The Nitzschia-type endosymbiont is genetically distinct from endosymbionts of other dinotomes with the same diatom type. In contrast, considering the known freshwater species of Durinskia, the genetic relationship between hosts is robust and of recent origin. The antiquity of the Mexican sequence coincides with the geological origin of the Xochimilco basin, suggesting particularities in the evolutionary history of dinotomes linked to the geographic regions they inhabit. Conclusions: Our evolutionary scenario with a calibrated phylogeny indicates that the transition of Durinskia baltica to freshwater in the Xochimilco basin is geologically contextualized. The historical environmental change of Lake Xochimilco with respect to salinity corresponds with an initial colonization of D. baltica in a brackish environment and its subsequent adaptation to freshwater.

Resumen El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

Abstract: The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

Resumen: La cuenca Salí-Dulce es una de las principales del Noroeste de Argentina y en su recorrido se ve afectada debido a la incorporación de sustancias contaminantes. En los ecosistemas acuáticos continentales las diatomeas constituyen un grupo destacado. Su biología y taxonomía son adecuadas para su uso en el biomonitoreo. El objetivo fue caracterizar la dinámica y la composición de las taxocenosis de diatomeas y su relación con variables ambientales en los arroyos Mista y Calimayo, pertenecientes a la cuenca del río Salí-Dulce (Tucumán-Argentina). Para esto se seleccionaron tres sitios en cada arroyo y se tomaron datos de variables ambientales y biológicas según metodologías convencionales. La calidad del agua fue variable según el aporte de contaminantes y la estacionalidad climática. El ensamble de diatomeas resultó ser una taxocenosis bioindicadora sensible a las características ambientales de los arroyos. En este trabajo se registraron 61 especies de las cuales 11 serían buenas indicadoras del estado de contaminación. El uso de dos índices bióticos permitió afirmar que el Índice de Diatomeas Pampeano modificado según datos propios, resultó más sensible y eficaz en la determinación de la calidad del agua, por lo que se podría considerar como una herramienta diagnóstica, de seguimiento de la calidad del agua y de planificación que serviría para brindar información válida y de fácil aplicación en cuencas del Noroeste de Argentina.

Summary: The Salí-Dulce basin is one of the main in the Northwest of Argentina and is affected by significant ecological changes due to the presence of polluting substances along its way. Diatoms are a prominent algal group in aquatic ecosystems. Their biology and taxonomy are suitable for their use in biomonitoring based on their specific responses to environmental changes. The objective of this study was to characterize the dynamic and composition of the taxocenosis of diatoms and their relationship with environmental variables in the Mista and Calimayo streams, belonging to the Salí-Dulce river basin (Tucumán-Argentina). For this, three sites were selected in each stream, and data on environmental and biological variables were collected according to conventional methodologies. Water quality was variable depending on the presence of pollutants and climatic seasonality. The diatom assemblage resulted as a sensitive taxocenosis bioindicator of the stream status. In this work, a total of 61 species were recorded, of which 11 could be good indicators for stream contamination. The use of two biotic indices makes it possible to affirm that the Pampean Diatom Index, modified on the basis of our data, resulted to be more sensitive and effective in determining water quality, which is why it could be considered as a tool for diagnosis, water quality monitoring and water planning that could provide valid information of easy application in basins of the Northwest of Argentina.

ABSTRACT Within the last decades, phytoplankton biomass has significantly risen in many lakes worldwide. Global warming was proposed as the most probable cause of the discovered effect. In this work, attention was paid to other drivers than just global warming, in particular, variability in solar radiation to explain this unexpected diatom shift. Here, we use a combination of paleolimnological, dendrochronological and meteorological datasets, as well as local pollution information, to analyze the recent growth of diatom total abundance in Lake Rabbvatnet (69.7º N, 30.5º E, Northern Norway). The results show that the diatoms of the genus Aulacoseira were most abundant in the top layers of the sediment core. On the contrary, the biomass of small-sized Cyclotella species, which, as a rule, should grow simultaneously with warming, has decreased over the past decades. We suggest basing on the experimental data analysis (comparison of diatom abundance with solar irradiance and heavy metals, testing of air temperature trends) that the recent growth of the total diatom abundance observed in the subarctic Rabbvatnet Lake could be mainly due to an increase in photosynthetically active spectral solar irradiance fluxes in the visible and infrared ranges. decades worldwide effect work particular shift Here paleolimnological datasets information 69.7º 697º º 69 7º N 305º 30 5º E Norway. Norway . Norway) core contrary smallsized small sized species which rule comparison metals trends ranges 6 3

Abstract Diatoms constitute a representative portion of the algal community of freshwater aquatic environments, but their studies are centered mostly in the south and southern regions of Brazil, making the microalgae biodiversity of water bodies in the semiarid practically unknown. In the state of Ceará, the few records of the Bacillariaceae are centered in the southern region of the state and are generally not identified at specific level. Denticula, Hantzschia, and Tryblionella are worldwide distributed diatom genera that belong to the family Bacillariaceae. The group is characterized by raphe located on a channel, internally supported by silica extensions, the fibulae. This is a taxonomic study on the genera Denticula, Hantzschia, and Tryblionella found in water bodies in northwestern Ceará state. Planktonic and periphytic samples were collected in four hydrographic basins, which are influenced by the semiarid climate, located in northwestern Ceará, northeastern Brazil. Fourteen infrageneric taxa were identified, described, and illustrated, all being pioneer citations for Ceará. The present study highlighted the underestimated diversity of diatoms in the semiarid region of Ceará and the need to cover undersampled or never explored regions to significantly contribute to the knowledge of the diatom flora and its distribution in Brazilian aquatic environments. environments Brazil unknown level Denticula Hantzschia channel extensions fibulae basins climate described illustrated

Resumo As diatomáceas constituem uma porção representativa da comunidade algácea de ambientes aquáticos dulcícolas, mas seu estudo está centrado principalmente nas regiões sul e sudeste do Brasil, sendo a biodiversidade das microalgas em regiões semiáridas praticamente desconhecida. No estado do Ceará, os poucos registros das Bacillariaceae estão centrados na região sul do estado e, geralmente, os táxons não se encontram identificados em nível específico. Denticula, Hantzschia e Tryblionella são gêneros de diatomáceas distribuídos mundialmente, pertencentes à família Bacillariaceae. O grupo caracteriza-se pela rafe localizada em canal, internamente estruturada por extensões de sílica, as fíbulas. Este é um estudo taxonômico sobre os gêneros Denticula, Hantzschia e Tryblionella encontrados em corpos d’água no Noroeste do estado do Ceará. Amostras planctônicas e perifíticas foram coletadas em quatro bacias hidrográficas, que sofrem influência do clima semiárido, localizadas na região noroeste do Ceará, nordeste do Brasil. Quatorze táxons infragenéricos foram identificados, descritos e ilustrados, sendo todos citações pioneiras para o Ceará. O presente estudo evidenciou a subestimada diversidade de diatomáceas na região semiárida cearense e a necessidade de ampliação de abranger coletas em regiões subamostrados ou nunca exploradas para contribuir de maneira representativa para o conhecimento da diatomoflora e de sua distribuição em ambientes aquáticos brasileiros. dulcícolas Brasil desconhecida Ceará geralmente específico Denticula mundialmente caracterizase caracteriza canal sílica fíbulas dágua d água hidrográficas semiárido ilustrados brasileiros

Abstract: Aim This study focused on the spatiotemporal variation of the benthic diatom community structure in salt marshes from the Patos Lagoon estuary and their relationship with environmental variables. Methods Samplings were carried out in the winter of 2010 and summer of 2011 (during El Niño and La Niña) in sites with different sediment granulometry, salinity, and distances from the Atlantic Ocean. The surface sediment was collected using a core (10 cm in diameter and 2 cm in depth) and the benthic diatoms were removed following the Trapping method, allowing the observation of live diatoms. Results The richness values (18 and 48 taxa), evenness (0.41 and 0.68), and Shannon diversity indices (2.02 and 3.31 bits/ind.) variations were not significative between the sites and seasons, although temperature and salinity differed significatively between winter and summer. However, the diatom's composition and distribution were related to temperature, salinity, and sediment particle size. Mainly the species Hippodonta hungarica, Luticola simplex Navicula cf. cryptotenelloides, N. erifuga, N. jacobii, Nitzschia filiformis var. conferta, Planothidium frequentissimum and Tryblionella calida were associated with lower temperature and lower salinity in the winter. The species Navicula cf. cryptocephala, N. phylleptosomaformis, Nitzschia pusilla, N. frustulum, N. scalpelliformis and Pseudostaurosiropsis geocollegarum were associated with higher temperature and higher salinity in the summer. Birraphid diatom taxa, mainly species of the genus Navicula and Nitzschia, were frequent or abundant in sandy sediments, and monoraphids, such as Planothidium frequentissimum, were frequent in sites where silt and clay predominated. Conclusions The composition of the benthic diatoms revealed variation between the sites in the winter and summer seasons, during El Niño and La Niña episodes. In winter, high rainfall and freshwater runoff maintained oligohaline condition in the marshes, while in summer, flooding with meso-poly-euhaline waters changed the diatom composition. The granulometry was an important factor in explaining the distribution of the birraphid and monorhapid taxa. Abstract variables 201 Ocean 10 (1 depth method 18 4 taxa , taxa) 0.41 041 0 41 (0.4 0.68, 068 0.68 68 0.68) 2.02 202 02 (2.0 331 3 31 3.3 bits/ind. bitsind bits ind seasons However s size hungarica cf cryptotenelloides N erifuga jacobii var conferta cryptocephala phylleptosomaformis pusilla frustulum sediments monoraphids predominated episodes mesopolyeuhaline meso poly euhaline 20 1 ( 0.4 04 (0. 06 0.6 6 2.0 (2. 33 3. bits/ind 0. (0 2. (2

Resumo: Objetivo Este estudo focalizou a variação espaço-temporal da estrutura da comunidade de diatomáceas bentônicas, em marisma do estuário da Laguna dos Patos e sua relação com variáveis ambientais. Métodos Amostragens foram realizadas no inverno de 2010 e verão de 2011(durande o El Niño e La Niña) em locais com diferentes granulometrias do sedimento, salinidades e distâncias do Oceano Atlântico. O sedimento superficial foi coletado utilizando um core (10 cm de diâmetro e 2 cm de profundidade) e as diatomáceas bentônicas foram removidas, seguinto o método Trapping, que permite a observação das diatomáceas vivas. Resultados As variações dos valores de riqueza (18 e 48 taxa), uniformidade (0.41 and 0.68) e índice de diversidade de Shannon (2.02 and 3.31 bits/ind.) entre os locais e estações não foram significativos, embora a temperatura e salinidade diferiram, significativamente, entre o inverno e verão. Entretanto, a composição e distribuição das diatomáceas estiveram relacionadas à temperatura, salinidade e tamanho de partícula do sedimento. Principalmente as espécies Hippodonta hungarica, Luticola simplex Navicula cf. cryptotenelloides, N. erifuga, N. jacobii, Nitzschia filiformis var. conferta, Planothidium frequentissimum and Tryblionella cálida, estiveram associadas às mais baixas temperatura e salinidade no inverno. As espécies Navicula cf. cryptocephala, N. phylleptosomaformis, Nitzschia pusilla, N. frustulum, N. scalpelliformis and Pseudostaurosiropsis geocollegarum estiveram relacionadas as mais altas temperatura e salinidade no verão. Diatomáceas birrafídeas, principalmente espécies do gênero Navicula e Nitzschia foram frequentes ou abundantes em sedimentos arenosos e, monorrafídeas, tais como Planothidium frequentissimum foram frequentes em locais, onde predominaram silte e argila. Conclusões A composição das diatomáceas bentônicas revelou variação entre os locais nas estações de inverno e verão, durante os episódios de El Niño and La Niña. No inverno, alta pluviosidade e alto escoamento de água doce manteve condição oligohalina nas marismas, enquanto que, no verão, a inundação de água meso-poly-euhalina mudou a composição das diatomáceas. A granulometria foi um fator importante para explicar a distribuição dos táxons birrafídeos e monorrafídeos. Resumo espaçotemporal espaço temporal ambientais 201 2011durande durande 2011 Niña Atlântico 10 (1 profundidade removidas Trapping vivas 18 4 taxa, taxa , taxa) 0.41 041 0 41 (0.4 0.68 068 68 2.02 202 02 (2.0 331 3 31 3.3 bits/ind. bitsind bits ind significativos diferiram significativamente Entretanto hungarica cf cryptotenelloides N erifuga jacobii var conferta cálida cryptocephala phylleptosomaformis pusilla frustulum birrafídeas monorrafídeas argila marismas mesopolyeuhalina meso poly euhalina monorrafídeos 20 1 ( 0.4 04 (0. 0.6 06 6 2.0 (2. 33 3. bits/ind 0. (0 2. (2

Resumen En este estudio se investigó la mortalidad de una tierra de diatomeas obtenida en Turquía codificada ACN-1 frente a adultos de la cucaracha alemana (Blattella gemanica L. Blattodea: Ectobiidae) en superficies de hormigón, cerámica y parqué. Se realizaron ensayos biológicos en tres superficies diferentes frente a adultos de B. germanica a dosis de 2,5; 5; 10 y 20 g/m2 de tierra de diatomeas ACN-1 durante 6 días. En todas las aplicaciones, el tiempo de exposición y las dosis causaron un efecto significativo en las tasas de mortalidad de los adultos de B. germanica. La tierra de diatomeas ACN-1 a 2,5 g/m2 causó un 97,5%, 92,3% y 90% de mortalidad de adultos de B. germanica en las superficies de hormigón, cerámica y parquet al final del primer día, respectivamente, y se obtuvo un 100% de mortalidad al final del segundo día en todas las condiciones con esta dosis. Para todas las demás dosis de aplicación, se observó una mortalidad del 100% de los adultos de B .germanica al final del primer día. En general, la actividad de mortalidad de la tierra de diatomeas ACN-1 contra los adultos de B. germanica resultó similar en las tres superficies. Al final del estudio, se reveló que la tierra de diatomeas ACN-1, que es inocua para el medio ambiente, tiene potencial para ser utilizada en el control de B. germanica, plaga de importancia sanitaria, y puede ser una buena alternativa en el control contra esta plaga.

Abstract In this study, the mortality of diatom earth from Turkey coded ACN-1 against the German cockroach (Blattella gemanica L. Blattodea: Ectobiidae) adults on concrete, ceramic and parquet surfaces was investigated. Biological tests were carried out on three different surfaces against the adults of B. germanica at doses of 2.5, 5, 10 and 20 g/m. diatom earth coded ACN-1 for 6 days. In all surface applications of ACN-1 diatomaceous earth, exposure time and doses caused significant effect on mortality rates of B. germanica adults. Diatom earth ACN-1 at 2.5 g/m. caused 97.5%, 92.3% and 90% of mortality of B. germanica adults on the surfaces of concrete, ceramic and parquet at the end of the first day, respectively and 100% of mortality was obtained at the end of the second day in all conditions with this dose. For all other application doses, 100% mortality of B .germanica adults was observed at the end of the first day. In general, the mortality activity of ACN-1 diatom eartn against B. germanica adults was found to be similar on all three surfaces. We conclude that the Turkish diatom earth coded ACN-1, which is harmless to the environment, has the potential to be used in the control of B. germanica, which is a medical pest, and can be a good alternative in the control against this pest.

Resumen El Instituto de Investigaciones Marinas y Costeras y la Agencia Nacional de Hidrocarburos de Colombia han llevado a cabo investigaciones de línea base ambiental en bloques de exploración de hidrocarburos aguas afuera del mar Caribe colombiano, entre los años 2008 y 2018. Estas investigaciones han generado información taxonómica y ecológica del fitoplancton marino, obtenida bajo diferentes métodos. El objetivo del presente trabajo fue unificar dicha información, certificando su veracidad. Para ello se organizaron matrices de datos, depurando la información, actualizando la taxonomía, categorizándola al nivel taxonómico de género, y estandarizando la abundancia. Aquí se pone a disposición una base de datos del fitoplancton oceánico del mar Caribe colombiano, con 5720 registros, a 2440 de los cuales se adicionaron abundancias. En general, este conjunto de datos recopila información de 8 proyectos, 14 cruceros, 12 bloques de exploración, 120 estaciones, y 304 lotes de muestras mixtas de fitoplancton, donde se registraron 135 géneros distribuidos en 80 familias, 45 órdenes, 9 clases y 7 fila. La abundancia se estandarizó a células por litro, obteniéndose un rango entre 9.6 y 7790.0 cél.L-1.

Abstract The Institute of Marine and Coastal Research and the National Hydrocarbons Agency of Colombia have carried out environmental baseline research in hydrocarbon exploration blocks outside the Colombian Caribbean Sea, between 2008 and 2018. These investigations have generated taxonomic and ecological information of marine phytoplankton, obtained under different methods. The objective of the present work was to unify such information, certifying its veracity. For this purpose, data matrices were organized, refining the information, updating the taxonomy, categorizing it at the genus level, and standardizing abundance. Therefore, a database of oceanic phytoplankton of the Colombian Caribbean Sea is made available, with 5720 occurrences, with abundance added to 2440 of them. In general, this data set gathers information from 8 projects, 14 cruises, 12 exploration blocks, 120 stations, and 304 lots of mixed phytoplankton samples, where 135 genera distributed in 80 families, 45 orders, 9 classes, and 7 phyla were recorded. Abundance was standardized to cells per liter, obtaining a range between 9.6 and 7790.0 cel.L-1.

ABSTRACT In Senado Formation, the knowledge about fossil diatoms flora is quite scarce; in Cuba, general speaking, studies are practically lacking. Determining Distephanosira architecturalis species represented a challenge due to its predominance in high latitudes. The aim of this research is to make public the first record of Distephanosira architecturalis for the Senado Formation in Central Cuba, providing its description based on biological microscopy. Distephanosira architecturalis was observed in sediments from Senado Formation, so its presence represents an extension of knowledge about distribution of taxon’s area and, in addition, allows us to consider the lower part of this unit with a stratigraphic distribution from the Middle Eocene.

RESUMEN En la Formación Senado el conocimiento de la flora fósil de diatomeas es bastante escaso y para Cuba en general, prácticamente se carece de estudios. La determinación de la especie Distephanosira architecturalis representó un desafío debido a su predominio en latitudes altas. Este artículo reporta el primer registro de D. architecturalis para la Formación Senado, en Cuba Central, proporcionando su descripción con base en microscopia biológica. D. architecturalis se observó en los sedimentos de la Formación Senado; por lo que su presencia representa una ampliación del conocimiento sobre el área de distribución del taxón y, además, permite considerar la parte inferior de dicha unidad con una distribución estratigráfica desde el Eoceno Medio.

Resumen La transmisión bacteriana al ser humano puede vehiculizarse por el agua y ocasionar enfermedades entéricas, por lo que el objetivo de la presente investigación es evaluar la efectividad del uso de diatomeas en la filtración de bacterias hidrotransmisibles. El estudio fue realizado en la Universidad Nacional de Chimborazo, Ecuador, desde octubre de 2019 a marzo de 2020, combinando técnicas de cultivo en agar sangre y agar MacConkey; cuantificación de colonias y filtración frente a tiempo y longitud de filtro. Se utilizaron 120 muestras de diluciones de cepas comerciales de Escherichia coli . Staphylococcus aureus para contaminar el agua de tal forma que se pudiera evidenciar la eficacia de la filtración en diatomeas de distinta procedencia. Los resultados fueron contrastados con los rangos establecidos por la Organización Mundial de la Salud y se realizaron controles positivos y negativos de los medios de cultivo y agua. Las diatomeas de Guayaquil fueron las que indujeron a una mejor filtración del agua frente a las diatomeas de Palmira. Al aplicar el lecho filtrante de 10 cm de diatomeas, se obtuvo un crecimiento de 86 UFC/100ml en 24 horas, mientras que al aumentarse la cantidad del filtro a 20 cm se observó un descenso de la carga bacteriana del agua en 21 UFC/100ml en 10 horas. De acuerdo al rango establecido por la OMS el crecimiento bacteriano disminuyó, lo que indica que los filtros de diatomeas tienen la capacidad de retener bacterias. Por esto, se presume que, al combinarlas con materiales adicionales como carbón activado, su potencial filtrante se incrementaría.

Abstract Bacterial transmission to humans can be carried by water and cause enteric diseases, so the objective of this paper isto evaluate the effectiveness of the use of diatoms in the filtration of waterborne bacteria. The study was carried outat Universidad Nacional de Chimborazo, Ecuador; from October 2019 to March 2020, combining culture techniques on blood agar and MacConkey agar, colony quantification and filtration versus filter time and length. 120 dilutions samples of commercial strains of Escherichia coli and Staphylococcus aureus were used to contaminate the water in such a way that the efficiency of filtration in diatoms of different origins could be observed. The results were contrasted with the ranges established by the World Health Organization and positive and negative controls were carried out on the culture media and water. The diatoms of Guayaquil were the ones that induced a better filtration of the water compared to the diatoms of Palmira. When applying the filter bed of 10 cm of diatoms, a growth of 86 CFU/100ml was obtained in 24 hours, while when the amount of the filter was increased to 20 cm, a decrease in the bacterial load of the water was observed by 21 CFU/100ml in 10 hours. According to the range established by the WHO, bacterial growth decreased, which indicates that diatom filters have the ability to retain bacteria. For this reason, it is presumed that, when combined with additional materials such as activated carbon, their filtering potential would increase.

Abstract Diatom assemblages and coastal sedimentary facies succession in the deltaic plain of the Colorado River (Argentina) were studied in order to reconstruct the environment conditions in response to Holocene eustatic sea-level changes and delta progradation. Samples were selected from a 200˗cm core (39°35’52” S, 62°6’43” W). Chronology was based on radiocarbon datings in bulk samples and mollusk shells. Nine lithological units were recognized where fine and very fine sand predominate. The core sediments were dominated by tychoplanktonic coastal-marine diatoms. The accompanying flora included stable marine-coastal taxa and allochthonous fluvial fresh-brackish species. Three diatom zones (DZ) were established based on cluster analyses. The LCH site was significantly affected by Late Pleistocene and Holocene sea˗level fluctuations, and the progradation of the deltaic lobe during the last ca. 7,000 14C yr. BP. Ancient tidal channels were flooded in the early Holocene postglacial transgression. Erosive and re˗working processes associated with the formation of estuarine channels, affected valves preservation, yielding with barren sections. Tidal flats and marshes have developed in the area during the late Holocene regression phase. The comparison of the sedimentary sequence with deltaic facies evolution models, confirm the presence of a hiatus, which masks the Holocene Maximum and highstand. Argentina (Argentina sealevel sea level 200cm cm 200 39°3552 393552 39°35 52 39 35 (39°35’52 S 62°643 62643 62°6 43 62 6 62°6’43 W. W . W) shells predominate coastalmarine marine diatoms marinecoastal freshbrackish fresh brackish species DZ (DZ analyses fluctuations ca 7000 7 000 7,00 C yr BP transgression reworking re working preservation sections phase models hiatus highstand 20 3552 39°355 39355 3935 39°3 5 3 (39°35’5 643 62°64 6264 626 62° 4 62°6’4 700 00 7,0 2 355 393 39° (39°35’ 64 62°6’ 70 0 7, (39°35 (39°3 (39° (39 (3 (