Sensor calibration for dissolved gas is a critical and necessary step to ensure consistent sensor response over time and under different conditions. In this work, we describe a 3D printed device that facilitates the calibration of gas sensors. The device effectively maintained gas concentration in the solution for at least 2 h. Analytical curves were constructed in the pH range of 2 to 12, yielding determination coefficients surpassing 0.98. The chosen method proved suitable for the calibration of the sensors. Furthermore, using accurate and reliable reference sensors contributed to obtaining precise and trustworthy measurements. conditions work D h 12 098 0 98 0.98 Furthermore measurements 1 09 9 0.9 0.

ABSTRACT The present study aimed to evaluate the ecology considering distribution, abundance, population structure, and fecundity of the marine diplostraceans Penilia avirostris and Pseudevadne tergestina in the Veracruz Reef System National Park, southwest Gulf of Mexico. Surface samples were collected with a 300 μm mesh plankton net at 26 sampling sites in June, August, October (2011), May (2012) and June (2013). Temperature, salinity, and dissolved oxygen were measured in situ. The temperature range was 26.53 ± 0.41 and 29.29 ± 0.27°C, salinity between 33.43 ± 0.49 and 35.91 ± 0.09, and dissolved oxygen between 2.92 ± 0.08 and 6.56 ± 0.08 mg L-1. P. avirostris and P. tergestina presented the highest density, with 2200 ind 100 m-3 in June and 5980 ind 100 m-3 in October, respectively. Four stages were determined in P. avirostris. In P. tergestina, there were five instars, with males in August and October. The size of parthenogenic females of P. avirostris was 773.4 ± 20.08 μm. In P. tergestina, it was 637.6 ± 49.28 μm. The number of embryos in P. avirostris was 2 to 7, and in P. tergestina, 2 to 8 embryos. The correlations between body length and the number of embryos in both species were statistically significant under the potential model (r > 0.68 for both species, P < 0.001). The transects with the highest abundance were the northern and the southern zones because they are far from the influence of the Jamapa River. The density of these crustaceans is related to optimal temperature, salinity, and dissolved oxygen values. The low proportions obtained from gamogenic individuals of P. avirostris and P. tergestina suggest that in tropical and subtropical regions, gamogenesis is not crucial for the life cycle of these organisms.

Abstract Common duckweeds are flowering plants of the family Araceae, comprising the smallest angiosperms of the plant kingdom, a species of aquatic algae of universal distribution, found on the surface of freshwater bodies, mainly in puddles, swamps, lakes, and calm rivers. Recently, different research has been carried out on its potential and usefulness. Due to its nutritional composition, protein contribution, high fiber content and low fat and carbohydrate content, it would be an adequate input to generate products of high nutritional value, characteristics that make it interesting compared to other species. It is used as a complement to commercial diets in a wide variety of animals such as birds, ruminants, non-ruminants, crustaceans, and fish, reducing feed costs by up to 50 %. Likewise, used in remediation processes of a wide range of chemical contaminants with a high elimination rate, they can absorb some dissolved substances and provide oxygen through photosynthesis. It has been indicated that they are low cost of construction, maintenance, easy to operate, have a wide tolerance to growing conditions, are generally easy to harvest, and do not compete with farmland. In the environmental field, it is important to find alternative and innovative raw materials, even without the need to use growth media or fertilizers, however, their acceptance as a food source needs extensive research regarding their nutritional value, large-scale yield, economic market supply and analysis of antinutritive components for human food.

Resumen Las lentejas de agua son plantas con flores de la familia Aráceas, comprenden las angiospermas más pequeñas del reino vegetal, una especie de algas acuáticas de distribución universal, se encuentran en la superficie de los cuerpos de agua dulce principalmente en charcos, ciénagas, lagos y ríos calmados. Recientemente, se han llevado a cabo diferentes investigaciones sobre su potencial y utilidad. Por su composición nutricional, aporte de proteína, alto contenido de fibra y bajo contenido de grasas y carbohidratos, resultaría ser un insumo adecuado para generar productos de alto valor nutricional, características que la hacen interesante frente a otras especies. Se emplea como complemento a dietas comerciales en una gran variedad animales como aves, rumiantes, no rumiantes, crustáceos y peces, reduciendo hasta un 50 % los costos por alimentación. Así mismo, usada en procesos de remediación de una amplia gama de contaminantes químicos con alta tasa de eliminación, pueden absorber algunas sustancias disueltas y brindar oxígeno mediante la fotosíntesis. Se ha indicado bajo costo de construcción, mantenimiento, fáciles de operar, poseen amplia tolerancia a condiciones de crecimiento, facilidad general de cosecha y no compiten con las tierras de cultivo. En el ámbito ambiental es importante encontrar materias primas alternativas e innovadoras, incluso sin la necesidad de utilizar medios de crecimiento o fertilizantes, sin embargo, su aceptación como fuente de alimento necesita investigaciones exhaustivas con respecto a su valor nutritivo, rendimiento a gran escala, suministro de mercado económico y análisis de componentes antinutritivos para la alimentación humana.

ABSTRACT The semi-permanent coastal upwelling system within the Humboldt Current System (HCS) off northern Chile provides nutrient-rich, oxygen-poor water to the euphotic zone that contributes to high levels of primary production and restricts the vertical distribution of most zooplankton species according to their tolerance to hypoxia within this highly heterogeneous environment. The day/night vertical distributions of two calanoid copepods, Eucalanus inermis and Nannocalanus minor, were studied concerning the presence of oxygen-poor water associated with the Oxygen minimum zone (OMZ) at a coastal and an offshore station off northern Chile (∼20°S), by stratified sampling from the surface to a depth of 600 m. At the coastal station, most of the population of both species remained above the OMZ, whereas at the offshore station, most populations remained at the edge of the OMZ. Both species exhibited reverse diel vertical migration between day and night and were positively correlated with dissolved oxygen and chlorophyll-a, suggesting that both species may prefer oxygenated waters and avoid the OMZ. However, E. inermis and N. minor exhibited distinct behavior, with E. inermis displaying significant variations among stations and strata and N. minor showing differences only among strata, particularly in the upper strata where it was more aggregated. The results helped us understand the behavior and distribution of zooplankton related to OMZ and how they may change as ocean temperature increases worldwide.

Resumen El género Isonychia agrupa efímeras con ninfas de gran tamaño presentes en ecosistemas lóticos. Este género tiene una distribución muy amplia, a pesar de ello, en México los registros son muy escasos y éstas no refieren las características ambientales de los sitios donde fueron encontradas. El objetivo de este trabajo es reportar por primera vez el género Isonychia en el estado de Durango, así como caracterizar algunos parámetros fisicoquímicos del agua asociados a su distribución. Se registraron 19 ninfas de Isonychia, que probablemente corresponden a la especie I. sicca, en siete sitios dentro de la cuenca del río Nazas. Esto amplía el rango de distribución del género Isonychia para México. Los ejemplares se registraron en ambientes con velocidad de corriente moderada y una calidad del agua aceptable en comparación con otros sistemas riparios, en términos de oxígeno disuelto, conductividad eléctrica, sólidos disueltos totales, pH, temperatura y amonio.

Abstract The genus Isonychia groups mayflies with large nymphs present in lotic ecosystems. This genus has a very wide distribution, despite of this, in Mexico the records are very scarce and these do not refer to the environmental characteristics of the sites where they were found. The objective of this work is to report for the first time the genus Isonychia in Durango state, as well as to characterize some physicochemical parameters of water associated with its distribution. A total of 19 Isonychia nymphs, which probably correspond to the species I. sicca, were recorded in seven sites within the Nazas River basin. This extends the distribution range of the genus Isonychia for Mexico. The specimens were recorded in environments with moderate current speed and an acceptable water quality compared to other riparian systems, in terms of dissolved oxygen, electrical conductivity, total dissolved solids, pH, temperature and ammonium.

Abstract 19. This study reports an episode of fish mortality occurred in the Garupá and Pindapoy Grande streams, near the confluence with the Paraná River (Garupá, Argentina). Dead and moribund fish of various species were observed floating on the water surface. Environmental parameters measured were temperature 5 °C, water temperature 15.1 (±0.6) °C, dissolved oxygen 8.7 (±1.2) ppm, pH 7.5 (±0.2), electrical conductivity 67.6 (± 8.8) mS cm-1 and mean depth of 1.7 (±1.0) m. Macroscopic examination of moribund fish revealed corneal opacity, whitish tegument, increased gill mucus, and whitish areas on gill filaments. Microscopic analysis of gills revealed severe generalized epithelial hyperplasia, lamellar fusion, congestion, and inflammatory infiltrate, particularly lymphocytes and eosinophilic granular cells. In addition, microscopic examination allowed the identification of the following ectoparasites found in gills and tegument: Chilodonella, Ichthyophthirius, Dactylogyridae and Trichodinidae, representing 98%, 1.2%, 0.6% and 0.2%, respectively. This study constitutes a novel record of wild fish mortality associated with extreme environmental conditions and parasitosis. Furthermore, our findings are significant as there are no prior reports in Argentina of epizootic cases linked to Chilodonella sp. infection in wild or farmed fish populations, being the first report of chilodonelliasis for this region.

Resumen 23. Este estudio reporta un episodio de mortandad de peces ocurrido en los arroyos Garupá y Pindapoy Grande, cerca de la confluencia con el río Paraná (Garupá, Argentina). En este tramo se encontraron flotando en la superficie del agua, peces moribundos y muertos de diferentes especies. Los parámetros medidos fueron: temperatura ambiental 5 °C, temperatura del agua 15,1 (±0,6) °C, oxígeno disuelto 8,7 (±1,2) ppm, 24. pH 7,5 (±0,2), conductividad 67,6 (± 8,8) mS cm-1 y profundidad media de 1,7 (±1,0) m. En el examen macroscópico de peces moribundos se observó opacidad corneal, tegumento blanquecino, aumento de moco branquial y áreas blanquecinas en los filamentos branquiales. El análisis microscópico de las branquias reveló hiperplasia epitelial generalizada grave, fusión laminar, congestión e infiltrado inflamatorio, particularmente linfocitos y células granulares eosinófilas. Además, el examen microscópico permitió identificar los siguientes ectoparásitos encontrados en piel y branquias: Chilodonella, Ichthyophthirius, Dactylogyridae y Trichodinidae, que representó el 98%; 1,2%; 0,6% y 0,2%, respectivamente. El presente estudio es un nuevo registro de mortandad de peces silvestres relacionada con condiciones ambientales extremas y parasitosis. Además, nuestro hallazgo aporta información valiosa, ya que en Argentina no existen registros de casos epizoóticos asociados a infección por Chilodonella sp. en poblaciones de peces silvestres o de criaderos, siendo el primer reporte de quilodonelliasis para esta región.

Abstract This study aimed to analyze the application of the Phytoplankton Community Index-PCI and Functional Groups-FG in determining the water quality of the Guamá River (Pará, Amazônia, Brazil). Samplings occurred monthly for analyses of phytoplankton and physical and chemical parameters, for two years, at the station where water was collected for human supply consumption. Seasonality influenced electrical conductivity, total suspended solids, dissolved oxygen, transparency, winds, true color, and N-ammoniacal. The ebb tide showed high turbidity and suspended solids. The density varied seasonally with the highest values occurring in September and December (61.1 ind mL-1 and 60.2 ind mL-1, respectively). Chlorophyll-a was more elevated in December (21.0 ± 4.7 µg L-1) and chlorophyll-c higher in relation to clorophyll- b indicated the dominance of diatoms. Functional Group P prevailed in the study months. Through the PCI índex the waters of Guamá River varied from reasonable to excellent and the TSI ranged from oligo to mesotrophic. The use of Functional Groups proved to be a promising tool in the determination of water quality since it covered the most abundant species in the Environment, but the PCI is not adequate to characterize Amazonian white-waters rivers, which have diatoms as the leading dominant group. IndexPCI Index GroupsFG FG Pará, Pará (Pará Amazônia Brazil. Brazil . Brazil) parameters years consumption conductivity solids oxygen transparency winds color Nammoniacal. Nammoniacal N ammoniacal. ammoniacal N-ammoniacal 61.1 611 61 1 (61. mL1 mL mL- 602 60 2 60. mL1, 1, respectively. respectively respectively) Chlorophylla Chlorophyll 21.0 210 21 0 (21. 47 4 7 4. L1 L L-1 chlorophyllc chlorophyll c clorophyll months mesotrophic Environment whitewaters white rivers group 61. 6 (61 21. (21 L- (6 (2 (

Leachate from a composting plant was characterized and applied as a biofertilizer in lettuce crops. Characteristics of untreated (UE) and anaerobically treated (TE) leachate samples were compared. The pH of TE (8.2) increased in relation to the UE (5.2) due to an increase in ammonia nitrogen in TE (1197 mg L-1) compared to UE (859 mg L-1). Anaerobic treatment was efficient in the removal of organic matter from the leachate, evaluated by the decrease of dissolved organic carbon, biochemical oxygen demand, total organic carbon and total solids. K presented the highest concentration (1743 mg L-1) in TE, followed by Mg (135 mg L-1). Cd, Pb and Cr were present at low concentrations in the samples, 0.047, 0.206 and 0.081 mg L-1, respectively. Salmonella, thermotolerant coliforms and viable helminth eggs were not present in TE, which was applied as a biofertilizer in a lettuce crop and compared to mineral fertilization based on fresh matter and dry matter production. Lettuce production using TE was statistically equivalent to mineral fertilization. Toxic metals were not detected in the lettuce shoots. It was concluded that the anaerobically treated leachate from the composting company has the potential to be used as a biofertilizer. crops (UE (TE 8.2 82 8 2 (8.2 5.2 52 5 (5.2 1197 (119 L1 L 1 L-1 859 (85 L1. . demand solids 1743 (174 135 (13 Cd 0047 0 047 0.047 0206 206 0.20 0081 081 0.08 L1, 1, respectively Salmonella shoots 8. (8. 5. (5. 119 (11 L- 85 (8 174 (17 13 (1 004 04 0.04 020 20 0.2 008 08 0.0 (5 11 ( 17 00 02 0.

There are many stilts and industry, which discharge sewage, domestic garbage and industrial effluents in the Pouca Saúde River from the port environment of Santos, São Paulo (SP) State. However, ecotoxicological studies in this river are rare. In this study, we seek to fill this gap by analyzing physicochemical, toxicological, and chemical conditions. Surface water and sediment samples were collected at 2 sampling sites with riparian community activities and industrial activities in the summer, autumn, winter and spring. The parameters analyzed were pH, alkalinity, turbidity, salinity, oils, greases, dissolved oxygen (DO), toxicological and cytotoxicity with mitotic index (MI) of onion roots using Allium cepa roots, and concentration of Pb, Zn, Hg, Ni and Cd. Our results showed alterations in the DO, turbidity, oils/greases and reduction of MI when compared to the respective control. Ni and Zn in sediment samples presented concentrations exceeding levels occasionally associated with adverse biological effects “threshold effect level”. These results suggested that the water quality of the Pouca Saúde River is influenced by both presences of heavy metals contamination and the seasons, i.e. by the tide. Thus, the toxic potential monitoring carried out in this study is of paramount importance to this river. industry sewage Santos SP (SP State However rare physicochemical conditions summer autumn spring pH alkalinity turbidity salinity oils greases DO , (DO) (MI Pb Hg Cd oilsgreases control threshold level. level . level” seasons ie i e i.e tide Thus (DO

Abstract Biological wastewater treatment is a process that removes pollution caused by carbon, nitrogen and phosphorus. For this purpose, aerobic microorganisms must have an adequate amount of oxygen to avoid slowing down this process. This research therefore evaluated the influence of dissolved oxygen concentration and time on the rate of microbial growth in wastewater samples. To do so, a mixed culture of aerobic microorganisms was used with an equivalent concentration of SSV=150 mg/L, dissolved oxygen levels of 2, 3, 4 ppm, observation time of 5 days and concentration of pollutants equal to 800 ppm. It was determined that the growth of microorganisms responded to the cell synthesis phase, and it increased from 150 mg/L of SSV to 386.9, 412.07 and 423.7 mg/L, depending on the level of dissolved oxygen (2, 3 and 4 ppm). On the other hand, as the treatment time elapsed, the rate of microbial growth decreased, despite the fact that the significance of the effect of dissolved oxygen concentration was negligible. Finally, time and the interaction of both variables were relevant. carbon phosphorus purpose samples so SSV150 SSV=15 mgL mg L 2 ppm 80 phase 15 3869 386 9 386.9 41207 412 07 412.0 4237 423 7 423. (2 . ppm) hand elapsed decreased negligible Finally relevant SSV15 SSV=1 8 1 38 386. 4120 41 0 412. 42 ( SSV1 SSV=

Resumo O tratamento biológico de águas residuais é um processo que remove a poluição por carbono, nitrogênio e fósforo. Para isso, os microrganismos aeróbicos devem receber uma quantidade adequada de oxigênio para evitar a desaceleração desse processo. Nesse sentido, nesta pesquisa, foi avaliada a influência da concentração de oxigênio dissolvido e do tempo na velocidade de crescimento microbiano em amostras de águas residuais. Para isso, foi utilizada uma cultura mista de microrganismos aeróbicos com uma concentração equivalente de SSV=150 mg/L, níveis de oxigênio dissolvido de 2, 3, 4 ppm, tempo de observação de 5 dias e concentração de poluente igual a 800 ppm. Foi determinado que o crescimento dos microrganismos respondeu à fase de síntese celular e aumentou de 150 mg/L de SSV para 386,9, 412,07 e 423,7 mg/L, dependendo do nível de oxigênio dissolvido (2, 3 e 4 ppm). Por outro lado, com o passar do tempo de purificação, a taxa de crescimento microbiano diminuiu, embora a significância do efeito da concentração de oxigênio dissolvido tenha sido insignificante. Por fim, o tempo e a interação de ambas as variáveis foram relevantes. carbono fósforo isso sentido pesquisa SSV150 SSV=15 mgL mg L 2 ppm 80 15 3869 386 9 386,9 41207 412 07 412,0 4237 423 7 423, (2 . ppm) lado purificação diminuiu insignificante fim relevantes SSV15 SSV=1 8 1 38 386, 4120 41 0 412, 42 ( SSV1 SSV=

Abstract The presence of invasive species can cause significant changes in native communities and ecosystem functions. Mexico is home to 6% of all known freshwater fish species on the planet, with a high rate of endemism. Due to heavy urbanization, the Mexican Central Plateau has become one of the most densely populated areas in the world, and its Tula River is considered one of the most polluted rivers in Mexico. Our objective was to investigate whether native fish species persist in such adverse conditions and to evaluate the seasonal and spatial distribution of both native and non-native species at three sites along the Tula River. We evaluated environmental characteristics and fish community structure. We found two native species, the black fin goodea (Goodea atripinnis) and the yellow shiner (Notropis calientis). However, their abundance was extremely low across all sites and seasons. In contrast, invasive poecilids dominated the communities, accounting for 99.4% of the total abundance. Our results indicate a clear relationship between river characteristics and fish community structure, highlighting the significance of river width, river velocity, temperature, dissolved oxygen, and pH. The prevalence of invasive species underscores the urgent need for conservation efforts aimed to protect and restore native fish populations. functions 6 planet endemism urbanization world nonnative non structure Goodea atripinnis Notropis calientis. calientis . calientis) However seasons contrast 994 99 4 99.4 width velocity temperature oxygen pH populations 9 99.

Resumen La presencia de especies invasoras puede causar cambios significativos en las comunidades nativas y en las funciones de los ecosistemas. México alberga el 6% de todas las especies de peces conocidas en el planeta, con una alta tasa de endemismo. Debido a la fuerte urbanización, el Altiplano mexicano se ha convertido en una de las áreas más densamente pobladas del mundo, y su río Tula es considerado uno de los ríos más contaminados de México. Nuestro objetivo fue investigar si las especies de peces nativos persisten en estas condiciones adversas y evaluar la distribución estacional y espacial de las especies, tanto nativas como no nativas, en tres sitios a lo largo del río Tula. Evaluamos características ambientales y la estructura de la comunidad de peces. Encontramos dos especies nativas, el Tiro (Goodea atripinnis) y la carpita amarilla (Notropis calientis). Sin embargo, sus abundancias se encontraron extremadamente bajas en todos los sitios y estaciones. En contraste, los poecílidos invasores dominaron las comunidades en todos los sitios y estaciones, representando el 99,4% de la abundancia total. Nuestros resultados indican una clara relación entre las características del río y la estructura de la comunidad de peces, resaltando la importancia del ancho del río, la velocidad del río, la temperatura, el oxígeno disuelto y el pH. La prevalencia de especies invasoras resalta la necesidad urgente de esfuerzos de conservación dirigidos a proteger y restaurar las poblaciones de peces nativos. ecosistemas 6 planeta endemismo urbanización mundo Goodea atripinnis Notropis calientis. calientis . calientis) embargo estaciones contraste 994 99 4 99,4 total temperatura pH 9 99,

Resumo O estresse ambiental causado pela poluição é frequentemente avaliado pela diversidade de espécies de macroinvertebrados em habitats aquáticos específicos. Para descobrir as flutuações sazonais em várias comunidades de macroinvertebrados e diferentes parâmetros de qualidade da água do rio Zhob, foi realizado um teste de pesquisa no rio Zhob, Baluchistão. Amostras de macroinvertebrados e água foram retiradas de quatro estações diferentes do rio Zhob. Um total de 18 táxons de vários macroinvertebrados foram identificados na área. O filo Arthropoda constitui 94,8% da população total, seguido por Mollusca (3,6%) e Annelida (1,4%). Um grande número de artrópodes pertencia à ordem Diptera (1148), enquanto a ordem Trichoptera ocupava o segundo lugar em número de macroinvertebrados (441). Os números máximos de macroinvertebrados foram observados no mês de janeiro. Todos os parâmetros físico-químicos do rio Zhob, como temperatura do ar, temperatura da água, pH, oxigênio dissolvido (OD) e sólidos dissolvidos totais (TDS), estavam dentro da faixa, adequada para o crescimento saudável de macroinvertebrados. Populações diversificadas de vários macroinvertebrados confirmam boas condições ecológicas do ambiente e da água no local estudado, especialmente a ampla concentração de DO no rio. Os dados documentados sobre macroinvertebrados no local estudado fornecerão uma linha de base para pesquisas futuras.

Abstract Environmental stress caused by pollution is often assessed by diversity of macro-invertebrate species in specific aquatic habitat. To find out seasonal fluctuations in various macro-invertebrates communities and different water quality parameters of River Zhob, a research trial was conducted on River Zhob, Balochistan. Samples of macro-invertebrates and water were taken from four different stations of River Zhob. A total 18 taxa of various macro-invertebrates were identified from the area. Phylum Arthropoda constitute 94.8% of the total population followed by Mollusca (3.6%) and Annelida (1.4%). A large number of arthropods were belonged to order Diptera (1148), while the order Trichoptera was stood second with respect to macro-invertebrate´s number (441). The maximum numbers of macro-invertebrates were observed in the month of January. All physico-chemical parameters of River Zhob such as air temperature, water temp, pH, dissolved oxygen (DO) and total dissolved solids (TDS) were within the range, suitable for the healthy growth of macro-invertebrates. Diversified populations of various macro-invertebrates confirm good ecological condition of environment and water in the studied site especially ample concentration of DO in River. The documented data on macro-invertebrates in studied site will provide a baseline for future research.

Resumo O trabalho de pesquisa foi projetado para investigar a densidade e diversidade de rotíferos pelágicos em um lago perto de Marala Headworks. Foram avaliados os parâmetros físico-químicos da água como pH, oxigênio dissolvido, temperatura, condutividade elétrica, transparência e turbidez. A correlação entre rotíferos e esses parâmetros também foi estudada. A amostragem do plâncton foi realizada mensalmente para verificar a densidade populacional dos rotíferos. No total, foram identificadas 18 espécies de rotíferos pertencentes a 11 gêneros. O maior número de rotíferos e sua diversidade foi demonstrado pelos gêneros Brachionus, Keratella e Filinia. O Brachionus calyciflorus foi a espécie dominante em todas as amostras, com densidade populacional média (41%). A análise de variância dos parâmetros físico-químicos mostrou que a temperatura do ar e da água, condutividade elétrica, transparência, oxigênio dissolvido e saturação de oxigênio foram estatisticamente significantes em todos os meses. Enquanto o pH foi estatisticamente não significativo (p≥0,05), a correlação de Pearson mostrou que o oxigênio e a transparência foram negativamente correlacionados com a densidade e diversidade dos rotíferos. A temperatura do ar e da água, a concentração de íons de hidrogênio (pH), a condutividade elétrica e a salinidade mostraram relação positiva com a densidade e diversidade de rotíferos.

Abstract Research work was designed to investigate the density and diversity of pelagic rotifers in a Lake near Marala Headworks. The physico-chemical parameters of water such as pH, dissolved oxygen, temperature, electrical conductivity, transparency and turbidity were evaluated. Correlation between rotifers and these parameters was also studied. Plankton sampling was done on monthly basis in order to check the population density of rotifers. In total, 18 species of rotifers were identified which belonged to 11 genera. The highest number of rotifers and their diversity was shown by genera namely Brachionus, Keratella, and Filinia. The Brachionus calyciflorus was dominant species in all the samples with mean population density (41%). Analysis of variance of physico-chemical parameters presented that the air and water temperature, electrical conductivity, transparency, dissolved oxygen and oxygen saturation were statistically significant in all the months. While pH was statistically non-significant (p≥0.05. Pearson correlation showed that oxygen and transparency were negatively correlated with rotifers density and diversity. Air and water temperature, concentration of hydrogen ions (pH), electrical conductivity and salinity showed positive relationship with density and diversity of rotifers.

Resumo Objetivo A alta sensibilidade das nascentes à impactos antrópicos deve-se, em grande parte, a elevada conectividade aquático-terrestre existente. A degradação desses ecossistemas pode ser causada pelo uso do solo, como por exemplo o monocultivo de eucalipto. O objetivo deste estudo foi testar a influência de plantações de Eucalyptus urograndis sobre a riqueza, a diversidade da comunidade de macroinvertebrados bentônicos e as variáveis ambientais aferidas em nascentes nos domínios de Floresta Atlântica. Métodos Dez nascentes (5 em áreas de floresta nativa e 5 em áreas de eucalipto) foram amostradas no período seco de 2017. Os organismos foram triados e identificados ao nível de família. Para cada nascente foram mensuradas o oxigênio dissolvido, temperatura, pH, turbidez, condutividade elétrica, sólidos totais dissolvidos, nitrogênio total, nitrito, nitrato, amônia, fósforo total, cobertura vegetal, caracterização granulométrica e matéria orgânica. Resultados O teste t evidenciou algumas variáveis ambientais diferiram, apresentando as áreas de eucalipto maiores valores de sólidos totais dissolvidos e condutividade elétrica e menores de areia muito grossa. No presente estudo, a riqueza e diversidade da fauna bentônica em nascentes foram significativamente menores nas áreas de eucalipto do que nas áreas de vegetação nativa. Entretanto, a composição das comunidades não diferiu. A análise de espécies indicadoras (IndVal) associou Acari, Hydropsychidae, Leptoceridae, Nematoda, Psychodidae e Tipulidae a áreas de floresta nativa. Conclusões Nossos resultados mostram que nascentes em áreas de eucalipto são afetadas pela monocultura reduzindo a riqueza e diversidade de macroinvertebrados bentônicos e alterando também os parâmetros ambientais. Por fim, verificamos que estudos anteriores em outras partes do mundo também se aplicam a áreas neotropicais onde o eucalipto não é nativo. devese, devese deve se, deve-se parte aquáticoterrestre aquático terrestre existente solo Atlântica ( 2017 família dissolvido temperatura pH turbidez total nitrito nitrato amônia vegetal orgânica diferiram grossa Entretanto diferiu IndVal (IndVal Acari Hydropsychidae Leptoceridae Nematoda fim nativo 201 20 2

Abstract Aim The high sensitivity of springs to anthropic impacts is largely due to the high existing aquatic-terrestrial connectivity. The degradation of these ecosystems can be caused by land use, such as eucalyptus monoculture. The aim of this study was to test the influence of Eucalyptus urograndis plantations on the richness and diversity of the benthic macroinvertebrate community and on the environmental variables measured in springs in the Atlantic Forest domains. Methods Ten springs (5 in native forest areas and 5 in eucalyptus area) were sampled in the dry period of 2017. The organisms were screened and identified at the family level. For each spring, dissolved oxygen, temperature, pH, turbidity, electrical conductivity, total dissolved solids, total nitrogen, nitrite, nitrate, ammonia, total phosphorus, vegetation cover, granulometric characterization and organic matter were also measured. Results: The t-test showed that some environmental variables differed, with the eucalyptus areas having higher values of total dissolved solids and electrical conductivity, and lower values of coarse sand. In the present study, the richness and diversity of the benthic fauna of springs were significantly lower in eucalyptus sites than in native sites. Nonetheless, the composition of the communities did not differ. The Indicator Species Analysis (IndVal) associated Acari, Hydropsychidae, Leptoceridae, Nematoda, Psychodidae, and Tipulidae with areas of native forest. Conclusions Our results show that Brazilian springs are affected by eucalyptus monocultures reducing the richness and diversity of benthic macroinvertebrates and also changing water environmental properties. Thus, we verified that previous studies elsewhere in the world also apply to neotropical areas where eucalyptus is not native. aquaticterrestrial aquatic terrestrial connectivity use monoculture domains ( area 2017 level spring oxygen temperature pH turbidity conductivity nitrogen nitrite nitrate ammonia phosphorus cover Results ttest t differed sand Nonetheless differ IndVal (IndVal Acari Hydropsychidae Leptoceridae Nematoda Psychodidae properties Thus 201 20 2

Resumo Objetivo Comparar variáveis ambientais e descritores das assembleias de peixes (composição de espécies, riqueza, dominância e diversidade) entre lagoas costeiras do sistema do rio Tramandaí, sul do Brasil. Métodos Amostras de água e de peixes foram coletadas mensalmente de Abril de 2009 a Março de 2010 na zona litoral de seis lagoas, três ao norte e três ao sul do estuário de Tramandaí. Treze variáveis ambientais de qualidade da água foram mensuradas. As capturas de peixes foram realizadas por meio de redes de emalhe. Usamos abordagem multivariada para investigar variações espaciais nas variáveis abióticas e diversidade de peixes. Resultados As amostras das lagoas ao norte (Itapeva, Quadros e Malvas) foram relacionadas com maiores valores de turbidez e demanda bioquímica de oxigênio, enquanto as amostras das lagoas ao sul (Fortaleza, Rondinha e Barros) com maiores valores de dureza, sólidos totais dissolvidos, transparência, condutividade elétrica e salinidade. As assembleias de peixes foram similares em composição de espécies entre as lagoas. A riqueza foi superior nas lagoas ao sul quando o mesmo número de exemplares foi considerado. Ao norte, as assembleias mostraram dominância numérica de Psalidodon aff. fasciatus e Loricariichthys anus, e menor diversidade, enquanto ao sul as assembleias foram mais equitativas e diversas. Conclusões Concluímos que as lagoas costeiras estudadas diferem no padrão de variação de parâmetros abióticos, refletindo em diferenças na qualidade da água. A composição e riqueza de espécies são similares e refletem a origem biogeográfica comum e recente das lagoas. As assembleias de peixes em lagoas grandes e turvas apresentam maior dominância enquanto as assembleias de peixes em lagoas pequenas e claras são mais diversificadas. Esses resultados podem ser úteis no manejo costeiro que prioriza os estoques pesqueiros ou na proposição de modelos de assembleias de peixes em lagoas costeiras subtropicais. Tramandaí Brasil 200 201 mensuradas emalhe Itapeva, Itapeva (Itapeva Malvas oxigênio Fortaleza, Fortaleza (Fortaleza Barros dureza dissolvidos transparência salinidade considerado aff anus diversas abióticos diversificadas subtropicais 20 2

Abstract Aim To compare abiotic variables and fish assemblage descriptors (species composition, richness, dominance and diversity) among coastal lagoons of the Tramandaí river system, southern Brazil. Methods Water and fish samples were taken monthly from April 2009 to March 2010 in the littoral zone of six coastal lagoons, three located at the north and three at the south of the Tramandai estuary. Thirteen environmental variables were measured. The fish assemblage samples were sampled with gillnets. We used multivariate analyses to investigate spatial variation in abiotic conditions and fish diversity. Results The samples at northern lagoons (Itapeva, Quadros and Malvas) were related to greater values of the turbidity and biochemical oxygen demand, while the southern lagoons (Fortaleza, Rondinha and Barros) were related to greater values of hardness, total dissolved solids, transparency, conductivity and salinity. The fish assemblages were similar in species composition. The species richness was higher in the southern lagoons when considering the same number of specimens. In the northern lagoons the assemblages were numerically dominated by Psalidodon aff. fasciatus and Loricariichthys anus and less diverse, while in southern lagoons were more equitable and diverse. Conclusions We concluded that the coastal lakes studied differ in the patterns of variation in abiotic parameters and this reflect in the water quality. Fish richness and species composition are similar, a likely result of the common and recent biogeographic origin of these lagoons. Fish assemblages in large and turbid lagoons present more dominance while the fish assemblages in small and clear lagoons are more diverse. These results may be useful for coastal management that prioritizes fish stocks or for proposing models of fish assemblages in subtropical coastal lagoons. diversity system Brazil 200 201 estuary measured gillnets Itapeva, Itapeva (Itapeva Malvas demand Fortaleza, Fortaleza (Fortaleza Barros hardness solids transparency salinity specimens aff diverse quality 20 2