Ocean-wide comparisons of mesopelagic planktonic community structures.

For decades, marine plankton have been investigated for their capacity to modulate biogeochemical cycles and provide fishery resources. Between the sunlit (epipelagic) layer and the deep dark waters, lies a vast and heterogeneous part of the ocean: the mesopelagic zone. How plankton composition is shaped by environment has been well-explored in the epipelagic but much less in the mesopelagic ocean. Here, we conducted comparative analyses of trans-kingdom community assemblages thriving in the mesopelagic oxygen minimum zone (OMZ), mesopelagic oxic, and their epipelagic counterparts. We identified nine distinct types of intermediate water masses that correlate with variation in mesopelagic community composition. Furthermore, oxygen, NO3- and particle flux together appeared as the main drivers governing these communities. Novel taxonomic signatures emerged from OMZ while a global co-occurrence network analysis showed that about 70% of the abundance of mesopelagic plankton groups is organized into three community modules. One module gathers prokaryotes, pico-eukaryotes and Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from oxic regions, and the two other modules are enriched in OMZ prokaryotes and OMZ pico-eukaryotes, respectively. We hypothesize that OMZ conditions led to a diversification of ecological niches, and thus communities, due to selective pressure from limited resources. Our study further clarifies the interplay between environmental factors in the mesopelagic oxic and OMZ, and the compositional features of communities.

Macroscale patterns of oceanic zooplankton composition and size structure.

Ocean plankton comprise organisms from viruses to fish larvae that are fundamental to ecosystem functioning and the provision of marine services such as fisheries and CO2 sequestration. The latter services are partly governed by variations in plankton community composition and the expression of traits such as body size at community-level. While community assembly has been thoroughly studied for the smaller end of the plankton size spectrum, the larger end comprises ectotherms that are often studied at the species, or group-level, rather than as communities. The body size of marine ectotherms decreases with temperature, but controls on community-level traits remain elusive, hindering the predictability of marine services provision. Here, we leverage Tara Oceans datasets to determine how zooplankton community composition and size structure varies with latitude, temperature and productivity-related covariates in the global surface ocean. Zooplankton abundance and median size decreased towards warmer and less productive environments, as a result of changes in copepod composition. However, some clades displayed the opposite relationships, which may be ascribed to alternative feeding strategies. Given that climate models predict increasingly warmed and stratified oceans, our findings suggest that zooplankton communities will shift towards smaller organisms which might weaken their contribution to the biological carbon pump.

Evaluation of microbiological and physical parameters of water from dental clinics in a brazilian university / Evaluación de parámetros microbiológicos y físicos del água de clínicas odontológicas en una universidad brasileña / Avaliação de parâmetros biológicos e físicas da água de clínicas odontológicas de uma universidade brasileira

Abstract Introduction and objective : Contamination of the water used in health care units can induce adverse individual and collective consequences. The objective of this study was to evaluate the water quality in dental clinics of a dentistry program of a university in Brazil, calculating the total coliforms, thermotolerant coliforms, heterotrophic bacteria and pH. Materials and methods: In each clinic, water samples were collected for analysis at different points: external cistern, clinic faucet, dental chair tank and triple syringe. After sample collection, analysis was performed: the presence of total coliforms and thermotolerant coliforms was determined by chromogenic substrate technique, the presence or absence of Escherichia coli by fluorescence in ultraviolet light, the count of heterotrophic bacteria through the number of colonies and the determination of pH. Results: In all studied sites, the presence of total coliforms, Escherichia coli and thermotolerant coliforms was observed in at least 26% of the samples. In relation to CFU / ml, all mean values were much higher than the maximum established by legislation (500 CFU / ml). It was verified a statistically significant difference was found in the external cistern and tap when compared to the chair tank and triple syringe (p < 0.05). All pH samples were within the standards. Conclusion : The global analysis showed that 100% of the samples were inadequate, which classified the water potability as nonstandard in regard to the current Brazilian legislation.

Resumen Introducción y objetivo : La contaminación del agua utilizada en las unidades de salud puede inducir malas consecuencias individuales y colectivas. El objetivo de esta investigación fue evaluar la calidad del agua en clínicas odontológicas de una universidad en Brasil, a través del análisis de coliformes totales, coliformes termotolerantes, bacterias heterotróficas y pH. Materiales y métodos: En cada clínica, las muestras de agua fueron recolectadas para análisis en diferentes puntos: cisterna externa, grifo clínico, reservatorio de la silla odontológica y jeringa tríplice. Después de la recolección de las muestras, el análisis fue realizado: la presencia de coliformes totales y coliformes termotolerantes fue determinada por la técnica del sustrato cromogénico; la presencia o ausencia de Escherichia coli por fluorescencia en luz ultravioleta; el recuento de bacterias heterotróficas a través del número de colonias y de la determinación del pH. Resultados: En todos los puntos estudiados, se observó la presencia de coliformes totales, Escherichia coli y coliformes termotolerantes en al menos el 26% de las muestras. Respecto a la UFC / ml, todos los valores medios fueron muy superiores al máximo establecido por la legislación (500 UFC / ml). Todas las muestras de pH estaban dentro de los patrones. Conclusión : El análisis global mostró que el 100% de las muestras fueron inadecuadas, lo que clasificó la capacidad de agua como fuera del estándar en relación a la legislación brasileña actual.

Resumo Introdução e objetivo: A contaminação da água utilizada nas unidades de saúde pode induzir consequências adversas individuais e coletivas. O objetivo deste estudo foi avaliar a qualidade da água em clínicas odontológicas de um curso de odontologia de uma universidade no Brasil, através da análise de coliformes totais, coliformes termotolerantes, bactérias heterotróficas e pH. Materiais e métodos: Em cada clínica, amostras de água foram coletadas para análise em diferentes pontos: cisterna externa, torneira clínica, reservatório da cadeira odontológica e seringa tríplice. Após a coleta das amostras, a análise foi realizada: a presença de coliformes totais e coliformes termotolerantes foi determinada pela técnica do substrato cromogênico; a presença ou ausência de Escherichia coli por fluorescência em luz ultravioleta; a contagem de bactérias heterotróficas através do número de colônias e a determinação de pH. Resultados : Em todos os pontos estudados, a presença de coliformes totais, Escherichia coli e coliformes termotolerantes foi observada em pelo menos 26% das amostras. Em relação à UFC/ml, todos os valores médios foram muito superiores ao máximo estabelecido pela legislação (500 UFC/ml). Todas as amostras de pH estavam dentro dos padrões. Conclusão: A análise global mostrou que 100% das amostras foram inadequadas, o que classificou a capacidade de água como fora do padrão em relação à legislação brasileira atual.

Global Trends in Marine Plankton Diversity across Kingdoms of Life.

The ocean is home to myriad small planktonic organisms that underpin the functioning of marine ecosystems. However, their spatial patterns of diversity and the underlying drivers remain poorly known, precluding projections of their responses to global changes. Here we investigate the latitudinal gradients and global predictors of plankton diversity across archaea, bacteria, eukaryotes, and major virus clades using both molecular and imaging data from Tara Oceans. We show a decline of diversity for most planktonic groups toward the poles, mainly driven by decreasing ocean temperatures. Projections into the future suggest that severe warming of the surface ocean by the end of the 21st century could lead to tropicalization of the diversity of most planktonic groups in temperate and polar regions. These changes may have multiple consequences for marine ecosystem functioning and services and are expected to be particularly significant in key areas for carbon sequestration, fisheries, and marine conservation. VIDEO ABSTRACT.

Bacterioplankton Activity in a Meso-eutrophic Subtropical Coastal Lagoon.

The aim of this study was to investigate whether the bacterioplankton activity in the meso-eutrophic Conceição Lagoon would increase significantly under allochthonous inputs of inorganic nutrients and organic carbon. Abundance and biomass of bacterioplankton were evaluated under three treatments: light (14 h light/10 h dark), complete darkness (dark-control), and nutrient (C + N + P-dark, 100 : 10 : 1) enrichments during 72 h. Nutrient enrichments promoted a significant increase in abundance (maximum of 19.0 ×109 cells·L-1 in the first 32 hours) and biomass of the heterotrophic bacterioplankton, which induced the formation of large clusters. Bacterial biomass remained constant in the non-enriched incubations (dark-control and light). Bacterial growth rates were significantly higher after nutrient additions (1.35 d-1), followed by control (0.79 d-1), and light (0.63 d-1) treatments, which were statistically equal (p > 0.05). Bacterial production rates were also significantly higher under nutrient additions (1.28 d-1), compared to the control and light (0.50 d-1 and 0.44 d-1, respectively), demonstrating that bacterial growth and production in this meso-eutrophic lagoon are under an immediate "bottom-up" regulation, followed by a potential top-down effect. These facts reinforce the urgency on improving the local wastewater management plan in order to prevent further expansion of anoxic waters.

Lysmata arvoredensis nov. sp. a new species of shrimp from the south coast of Brazil with a key to species of Lysmata (Caridea: Lysmatidae) recorded in the southwestern Atlantic.

Lysmata arvoredensis sp. nov. inhabits temperate waters in the south coast of Brazil and is named in tribute to the Marine Protected Area REBIO Arvoredo. This is the fourth species belonging to the genus Lysmata recorded for the region and the ninth for Brazil. L. arvoredensis sp. nov. can be distinguished from other species of Lysmata by the presence of a nearly completely fused accessory branch with a single free unguiform segment on the outer antennular flagellum; a rostrum with seven dorsal (2+5) and three ventral teeth; a stylocerite with a pointed tip bearing mesial setae; a second pereiopod with 22-24 carpal subsegments and 14-16 subsegments in the merus; a merus of the third pereiopod with five ventrolateral and 12 ventral spines on the propodus; and its color pattern, with red bands and patches in pleonites 2-3 that resemble a mask in dorsal view. Molecular characters demonstrate that L. arvoredensis sp. nov. is most closely related to other species of Lysmata belonging to the Neotropical and Cleaner clades. To support future ecological studies in the region, identification keys to the species of Lysmata recorded in the southwestern Atlantic Ocean are provided.