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Copyright of International Journal of Professional Business Review (JPBReview) is the property of Open Access Publications LLC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phylliroe bucephala is a nudibranch notable for having a laterally compressed body and a pelagic lifestyle. Although P. bucephala is widely distributed in tropical and subtropical waters of the Atlantic, Pacific, and Indian Oceans, it has not been recorded in the Colombian Pacific. Here we report the presence of the species in the coastal zone of Nuquí and Pizarro, two localities of Chocó - Colombia, and describe the main characteristics of the specimens collected. [ABSTRACT FROM AUTHOR]

This is the first study related to the zooplankton assemblage in the La García reservoir, an equatorial high Andean reservoir located in the central region of the department of Antioquia (Colombia). The main objective of the work was to know the composition and abundance of the zooplankton assemblage in the reservoir and to establish if there is any relationship between these and the physical and chemical variables measured. It was carried out during a monitoring program between the months of June and September 2014. Monthly samples were taken at three stations, from five depths throughout the water column, with a 10 L capacity sampling bottle. The collected material was filtered through a plankton net with a 30-mm of mesh size, identified and counted under an inverted microscope using a Sedgwick-Rafter counting cell. Depth and rainfall were the variables that exerted more influence on the zooplankton assemblages, reaching the highest density during the driest season, in the shallowest station and the least Secchi transparency. [ABSTRACT FROM AUTHOR]

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The studies carried out in extreme environments are of vital importance to know the variability of plankton in low temperature conditions, during the Southern summer, during the XVIII Ecuadorian Antarctic Expedition, between January and February 2014, the study area was located in the Guayaquil Cove and Chile Bay (Greenwich Island), plankton samples were collected at surface and vertical level using simple cylindro-conical-conical nets of 335µ and 50µ respectively, in order to determine the distribution of phytoplankton and zooplankton. Ten sampling stations were carried out in Guayaquil Inlet and 8 stations in Chile Bay in both strata. Nineteen phytoplankton species were identified at surface level and Thalassiosira sp. 60.3%, Cyclotella sp. 12.4% and Corethron criophylum with 12.7% were observed as dominant and 9 species in the water column, being dominant Thalassiosira sp. 52%, Cyclotella sp. 25% and C. criophylum with 11%, observing a 68.12% of dissimilarity between both zones, registering as dissimilar species Thalassiosira sp, Cyclotella sp., Limnophora abreviata, Synedra ocus and Diploneis coffeif.ormis. In Chile Bay, 19 species were recorded at surface level, with two dominant species, Cyclotella sp. 36% and C. criophylum with 28%, while 10 species were recorded in the water column, with Cyclotella sp. 45% and C. criophylum 25%. Zooplankton was represented in Guayaquil Cove by 11 groups, with copepods and amphipods as dominant, in the vertical there were 7 groups represented mostly by copepods, in Chile Bay in both strata an average of 6 groups were recorded and copepods were the dominant ones. Within the Ecological indexes in the phytoplankton recorded a Shannon value of 1.3 bits/cel at the surface level and 1.2 bits/cel in the vertical, Simpson of 0.4 bits/cel in both strata and Pielou recorded an average of 0.75 bits/cel, in Guayaquil Inlet, in Chile Bay at surface level a H value of 1.5 bits/cel and 1.2 bits/cel in the vertical was observed, Simpson with an average of 0.35 bits/cel in both strata and Pielou with 0.70 bits/cel at surface level and 0.9 bits/cel in the vertical. [ABSTRACT FROM AUTHOR]

Mesocyclops leuckarti is a zooplankton that is potentially suitable as a live food for freshwater fish larvae. Aquaculture farmers often struggled to create nutritious live feed to maximize the production of larval fish. This study aimed to determine the effects of different enrichments on life-table parameters, protein, lipid and fatty acid content of M. leuckarti when enriched with different dietary enrichments. In this study, five treatments for raising the copepod were compared: rice bran, soybean meal, Chlorella sp., Spirulina sp., and unenriched (control). The results showed that M. leuckarti after 16 days of cultivation enriched with rice bran produced a higher population density (53.3 ind/ml) and survival rate (97.4%) than when cultivated with any of the other diets. In terms of nutritional value, protein content was higher in M. leuckarti enriched with rice bran (52% DW) and soybean meal (53% DW). However, lipid content was highest in M. leuckarti enriched with rice bran (14% DW). Fatty acids, such as α -linolenic acid ALA (7.21%) and docosahexaenoic acid DHA (6.26%) were higher in M. leuckarti enriched with rice bran. Eicosapentaenoic acid EPA (7.16%) and arachidonic acid ARA (7.74%) were higher in M. leuckarti enriched with Chlorella sp. This study suggests that organic by-products are better sources for strengthening and improving the growth performance and life history of this copepod, and possibly also of zooplankton organisms in general. [ABSTRACT FROM AUTHOR]

Copyright of Ecoscience (Ecoscience) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Zooplankton is one of the most important trophic components for the functioning of aquatic ecosystems, these organisms are the food base of fish and contribute to the cycling of nutrients. The challenge of this study was to find temporal variations of taxonomic composition, structure, and diversity of zooplankton and their relationship with environmental variables in the Ciénaga de Paredes from 2013 to 2014. We worked with zooplankton samples deposited in the Natural History Museum UIS and the community structure was evaluated, using Hill's effective numbers and analysis of variance to determine significant differences between floodplain periods. Non-metric Multidimensional Scaling showing low stress (0.073). Transparency, deep, and conductivity showed significant differences during the floodplain periods. Rotifers were the most representative group, these organisms could be favored by the tolerance of the fluctuations in the water column. Keratella americana and Lecane proiecta were the most abundant species throughout the study period. There are cosmopolitan species characteristic of eutrophic systems, with a high load of nutrients and organic matter, as is observed in the Ciénaga de Paredes. The specific diversity decreased compared to a previous study in this area, which may suggest changes in the characteristics that could affect the functioning of the ecosystem. Fifteen new records are reported for the department of Santander. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El objetivo de esta investigación fue establecer el biofloc a tres relaciones carbono/ nitrógeno (C/N): 10/1, 15/1 y 20/1, determinando la secuencia de remoción de N, el perfil de sólidos y la caracterización del zooplancton, para tal fin se dispuso de tres tanques con volumen de 7000 L, incorporando oxígeno al agua a través de un aireador tipo soplador. Se utilizó como fuente de N balanceado, fuente de carbono melaza y bicarbonato de sodio como fuente alcalinizante. Al inicio se incrementó el nitrógeno amoniacal total NAT a 2 mg/L, la alcalinidad total (AT) a 120 mg/L y se adicionó como inóculo 10 litros/tanque de agua proveniente de un estanque de cultivo, al sexto y décimo días se adicionó balanceado incrementando teóricamente el NAT en 4 mg/L y a partir del día 12 en 1 mg/L. En las tres relaciones C/N se evidenciaron procesos de nitrificación durante la estabilización del biofloc, hasta llegar en el tiempo a concentraciones no letales de amonio y nitrito para peces, menores a 1 mg/L. En cuanto a los sólidos volátiles, se encontró una mayor concentración en la relación 20/1, lo cual puede atribuirse a la mayor adición de melaza, con la consecuente producción de SSV a partir de la dominancia de comunidades heterotróficas, en los tres macrocosmos se presentaron comunidades del zooplancton, no obstante, el T2 presentaron la mayor abundancia y riqueza de organismos. Las tres relaciones C/N en biofloc establecieron condiciones de calidad de agua y alimento vivo.

Copyright of Revista de la Facultad de Medicina Veterinaria y de Zootecnia is the property of Revista de la Facultad de Medicina Veterinaria y de Zootecnia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The assessment of zooplankton spatial structure is critical to quantifying plankton production and biochemical cycling. Here, we show the effect of monsoon-driven hydrographic changes on the spatial patterns of zooplankton at regional scales. Based on a field survey conducted during the monsoon transition, we assess the community structure and ash-free dry weight above 100 m depth in the Kuroshio edge area, southeastern East China Sea. The zooplankton community was dominated by copepods, with calanoids as the most abundant taxon followed by poecilostomatoids. Copepod assemblages comprised 81 species belonging to 41 families, and 23 genera, with Undinula vulgaris as the most abundant species. The richness of zooplankton taxa showed a mounting trend from the coast to offshore, which was opposite to the spatial variation of total zooplankton biomass. Our results suggest a leading influence of the Kuroshio Current during the southwest-northeast monsoon transition period in the southeastern East China Sea. Résumé: L'évaluation de la structure spatiale du zooplancton est essentielle pour quantifier la production du plancton et les cycles biochimiques. Ici, nous montrons l'effet des changements hydrographiques induits par la mousson sur les modèles spatiaux du plancton à l'échelle régionale. À partir d'un suivi sur le terrain mené pendant la transition de la mousson, nous avons évalué la structure de la communauté et le poids sec sans cendres au-dessus de 100 m de profondeur dans la zone du bord du Kuroshio, au sud-est de la mer de Chine orientale. La communauté zooplanctonique était dominée par les copépodes, avec les calanoïdes comme taxon le plus abondant suivis par les poecilostomatoïdes. Les assemblages de copépodes comprenaient 81 espèces appartenant à 41 familles, et 23 genres, avec Undinula vulgaris comme l'espèce la plus abondante. La richesse des taxons du zooplankton a montré une tendance croissante de la côte vers le large, qui était opposée à la variation spatiale de la biomasse totale du zooplancton. Nos résultats suggèrent une influence prépondérante du Courant de Kuroshio pendant la période de transition de la mousson sud-ouest/nord-est dans le sud-est de la mer de Chine orientale. [ABSTRACT FROM AUTHOR]

El presente trabajo se realizó en el lago Chongón, Guayas, ubicado en el Km. 26 de la vía a la Costa, al oeste de Chongón, con una posición geográfica de 02º13’08.61’’S y 80º07’31.86’’O. Se realizaron cuatro salidas de campo entre los meses de diciembre del 2011 y abril del 2012. Las muestras de zooplancton se obtuvieron en ocho estaciones, de las cuales cuatro se encontraban ubicadas en la zona litoral y cuatro en la zona limnética. Se encontraron 12 especies de cladóceros, pertenecientes a 11 géneros y 7 familias: Chydorus sphaericus Müller, 1785; Kurzia latissima Kurz, 1874; Leydigiopsis brevirostris Brehm, 1938; Alonella nana Baird, 1843; Bosmina longirostris O.F. Müller, 1776; Moina micrura Kurz, 1874; Ceriodaphnia cornuta Sars, 1885; Simocephalus vetulus OF Müller, 1776; Simocephalus acutifrons Johnson, 1954; Diaphanosoma brachyurum Liévin, 1848; Ilyocryptus spinifer Herrick, 1882 y Drepanothrix dentata Eurén, 1861. La diversidad obtuvo un índice alto, con H’= 2.2440 bitios y una equitatividad de E=0.6259. Los índices de diversidad para las zonas litoral y limnética, muestran una diferencia notable a favor de la zona litoral con un valor de H’= 2.7228 bitios y una equitatividad de E=0.8197 versus H’=0.3169 bitios y E= 0.0916 para la zona limnética. Esto confirma la hipótesis que sostiene que la zona litoral presenta una mayor densidad y diversidad de cladóceros.

El presente artículo plantea la evaluación de la contaminación en la Laguna El Pino, Barberena, Santa Rosa, Guatemala, mediante la utilización del plancton animal como indicador y la relación con los factores ambientales determinantes para su desarrollo, en el periodo de noviembre 2014 a febrero del 2015. Se identificaron 13 especies pertenecientes a tres clases: 4 protozoos, 3 rotíferos, 6 crustáceos (2 cladóceros, 4 copépodos). La especie más frecuente durante el estudio fue Achanthocyclops vernales, presente en la mayoría de muestras alcanzando una densidad de 54 org/ml. Entre los cladóceros se encontró como especie más frecuente a la Daphnia (47 org/ml). Entre los rotíferos la especie con mayores densidades fue la Polyarthra (54 org/ml). En los protozoos la especie más frecuente y de mayores densidades fue Strobilidium (93 org/ml). La mayor abundancia de zooplancton se registra al iniciar el estudio en noviembre del año 2014. Este cuerpo de agua está catalogado como mesotrófico, con temperaturas entre 27.0 – 23.0 °C, con una transparencia que oscila entre 1.60m.- 5.55m. El sistema lacustre presenta una buena calidad de agua, con buena producción de peces y crustáceos, razón por la cual poblados cercanos practican la pesca que representa una buena fuente de ingresos.

Snappers are marine fishes, but juveniles of many species migrate to estuaries, using these systems as nursery areas. The purpose of this study was to know the environmental factors mainly related to the migration patterns of lutjanids in La Mancha lagoon inlet. During 19 months, 24-hour cycles were performed monthly, taking samples every two hours (442 samples). Environmental variables recorded in situ and with regional records such as rainfall, atmospheric temperature and day length were considered. Genetic barcoding (COI) was used to validate species identity. Significant differences were evaluated by PERMANOVA and a Canonical Correspondence Analysis was used to determine the importance of environmental variables. Six species were recorded and the most abundant showed significant differences among months, with migration patterns during the warm-rainy season. Day length, salinity and rainfall (two of them with regional incidence) were the variables significantly associated with the distribution of the species. The abundance of Lutjanus analis, L. jocu, and L. cyanopterus was inversely associated with the length of daylight and directly related to rainfall, while L. synagris and L. griseus showed segregation along a salinity gradient. Thus, migration patterns were mainly correlated with factors of regional coverage and greater seasonal influence. [ABSTRACT FROM AUTHOR]

The natural food is an alternative in aquaculture due to several factors, including lower cost and not be artificial. Several works have emphasized the relationship between microalgae, zooplankton and larval periods of some animals, aimed at a better understanding in the dynamics of the food chain in aquatic bodies. The objective of the present study is to analyze the population dynamics of Macrothrix cf. triserialis (Cladocera, Macrothricidae) under different food quantity treatments (T103, T104 e T105) and different algal diet (mixed culture and Kirchneriela contorta unialgal culture). M. cf. triserialis using unialgal culture, had the highest population density of over 70 ind./ml, in the treatment T104 on 11thday of analysis and in relation to juveniles, it was observed that in treatment T10? individuals failed to survive. In this culture, the fertility rate was higher in the T104 and in 105 treatment eggs or embryos were observed only on 4th day. In the mixed culture, the greatest population density was obtained in treatment T105; M. cf. triserialis. juvenile were found throughout the study period and in all treatments. The fertility rate was highest in mixed cultures in treatments T10? and T105. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Universitaria is the property of Universidad de Guanajuato/Acta Universitaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

RESUMO Testaram-se as hipóteses de que, assim como em reservatórios de grande áreas de superfície, volumes e vazão, em reservatórios pequenos também ocorrem a diluição gradual e contínua da riqueza, da diversidade e abundância de microcrustáceos (Cladocera e Copepoda) a jusante dos mesmos, sem a recomposição da riqueza a jusante pela falta de rios tributários, lagoas marginais e até pelo pequeno porte do riacho, sem condições para o desenvolvimento do potamoplâncton próprio do sistema. Foram estudados dois pequenos reservatórios e seus trechos a jusante, com coletas diárias a cada seis horas em oito pontos de amostragem, sendo dois lênticos e seis lóticos a jusante de cada. Foram encontradas 19 espécies (11 de Cladocera e oito de Copepoda), com destaque para o maior número de espécies litorâneas do que pelágicas, e a maior abundância de cladóceros litorâneos nos pontos a jusante dos reservatórios. Não houve diferença entre os horários, indicando que a escala espacial foi mais importante que a temporal. Houve maiores valores dos atributos ecológicos nos ambientes lênticos, porém houve aumentos significativos de riqueza e diversidade nos últimos pontos dos trechos de riacho, enquanto que a abundância diminuiu gradativamente a jusante. Não foram encontradas correlações significativas da abundância dos táxons com nenhuma variável limnológica (temperatura, pH, oxigênio dissolvido, turbidez, sólidos totais dissolvidos e transparência), indicando pouco ou nenhum efeito destas variáveis. A análise de cluster com distância euclidiana separou dois grandes grupos, o primeiro formado pelo trecho a jusante do primeiro reservatório e o segundo com os demais pontos. Além da presença dos táxons litorâneos vindos dos reservatórios, houve incremento de táxons litorâneos residentes nos riachos. Pode-se concluir que houve uma diluição da abundância das espécies a jusante dos riachos, mas a riqueza e a diversidade permaneceram estáveis devido à contribuição de táxons litorâneos.

Se analizaron los microcrustáceos acompañantes de poslarvas de peneidos entre la desembocadura del Río Presidio y zona marina (sur de Sinaloa, México). Los muestreos fueron en mareas altas (mayo a octubre 2017). Se utilizó una red de plancton a profundidad de 1 m con arrastre de 2 h en 24 h. La temperatura del agua (25 a 34 ◦C) y salinidad (32 a 36 ups). La composición taxonómica en poslarvas fue: Penaeus vannamei, P. stylirostris, P. californiensis y P. brevirostris. Cladóceros: Penilia sp, Evadne sp y Pseudoevadne sp. Copépodos: Labidocera sp, Subeucalanus sp, Pseudocalanus sp, Centropages sp1 y Centropages sp2. La mayor frecuencia de aparición Labidocera sp y de abundancia relativa Penilia sp. Los microcrustáceos en promedio midieron menos de 11 mm, las mayores tallas poslarvas y menores a cládoceros. Por abundancia y frecuencia, Penilla sp, Labidocera sp, P. vannamei, P. californiensis y P. brevirostris, dominaron las capturas.

La Formación Meauco, región medanosa del centro de La Pampa, tiene numerosas lagunas. Si bien existe información hidrológica, el conocimiento sobre sus características limnológicas es escaso. Los objetivos son conocer parámetros físico-químicos y del zooplancton de dos lagunas cercanas, Santa Isabel I (SI I), con una población de pejerrey (Odontesthes bonariensis) y Santa Isabel II (SI II), sin peces, y evaluar la influencia del zooplancton sobre la biomasa fitoplanctónica y transparencia. Se muestreó durante 2018 y 2019. En ambas la salinidad fue menor a 1 g.L-1 y la profundidad del disco de Secchi rondó 0,45 m. Sus concentraciones de clorofila-a variaron entre 9,32 y 11,63 mg.m-3. Se registraron 7 taxa de cladóceros, 4 de copépodos y 20 de rotíferos, la mayor parte compartidos por ambas lagunas. Sin embargo, en SI I se registraron 20 rotíferos y en SI II 13. La densidad total no difirió, pero SI I tuvo mayor abundancia de rotíferos (69% del total) y SI II de crustáceos (72%). La presencia de peces influye sobre la composición del zooplancton, pero el tamaño pequeño de éste, aún en ausencia de peces, hace que tenga poca influencia sobre el fitoplancton; por lo que no se encontraron diferencias en la transparencia y biomasa fitoplanctónica de ambas lagunas.

Fêmeas ovadas foram expostas a quatro diferentes concentrações de cromo durante 96 horas. Posteriormente, as fêmeas foram transferidas para água de cultivo (descontaminação) durante oito dias. Na exposição foram observados parâmetros reprodutivos e mortalidade. Na descontaminação foi avaliado o sucesso reprodutivo das fêmeas (tempo para produção de saco de ovos e número de náuplios), desenvolvimento da prole e parâmetros populacionais. Durante a exposição não foram observadas mudanças significativas nos parâmetros avaliados. No bioensaio de descontaminação, as fêmeas do grupo controle demonstraram normalidade no comportamento reprodutivo, enquanto que as fêmeas expostas ficaram desovadas por mais tempo reduzindo a produção de náuplios. Com relação ao desenvolvimento, observou-se um retardo nas transições dos estágios larvais, sobretudo de copepodito para adulto, demonstrando uma menor densidade populacional. Portanto, concentrações subletais de cromo podem prejudicar a fisiologia reprodutiva, retardar o desenvolvimento e diminuir a densidade populacional de Tisbe biminiens.

Analizamos la composición específica de los eufáusidos presentes en las muestras de zooplancton obtenidas durante las campañas Pacífico-ERFEN de septiembre de 2009, octubre de 2011 y septiembre de 2012 en la cuenca Pacífica de Colombia. Identificamos un total de 15 especies (5 géneros). De las 15 especies, 9 ya habían sido previamente reportadas para la cuenca Pacífica colombiana, mientras que aquí reportamos por primera vez otras 6 especies (Thysanopoda monacantha, Euphausia lamelligera, E. gibboides, Stylocheiron longicorne, S. maximum y Nematoscelis tenella). De estas sies especies había registros en aguas adyacentes a la cuenca Pacífica colombiana, en coordenadas correspondientes al Golfo de Panamá, el Pacífico de Ecuador y Costa Rica.

El zooplancton es un integrante importante dentro de la comunidad biótica en un ecosistema acuático ya que actúan como bioindicadores, es por eso que el objetivo del presente trabajo fue determinar el efecto de los factores ambientales sobre la diversidad zooplanctónica en las lagunas del Parque Ñu Guasú. Para ello se tomaron muestras de agua, se midieron in situel pH, la conductividad, la temperatura y el oxígeno disuelto y en el laboratorio la DBO5, la DQO, la turbidez, el Nitrógeno Total y el Fósforo Total. Para los análisis biológicos se determinaron la riqueza específica y la abundancia y se emplearon el coeficiente de correlación de Pearson y el análisis de redundancia canónica (RDA). Se registraron diez morfotaxas siendo los rotíferos los más abundantes. Se identificaron 8 especies en la Laguna 1 y 7 especies en la Laguna 2. La abundancia en la Laguna 1 y 2 fue de 90 y 87 individuos respectivamente. Los factores ambientales tuvieron mayor influencia sobre las especies en la Laguna 1 fueron el Fósforo Total, la transparencia y la temperatura frente a Philodina sp. Macrothrix elegansy Sida crystallina, mientras que en la Laguna 2, el Nitrógeno Total, el Fósforo Total y el pH tuvieron mayor relación con las especies Keratella cochlearis, Alona sp., Sida crystallinay Eudiaptomus gracilisconcluyendo la comunidad de zooplancton de ambas lagunas respondió de distinta manera a los factores ambientales.

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Monstrilloid copepods are protelean parasites of marine benthic invertebrates; their juvenile stages are entirely endoparasitic and emerge from the host as free-living reproductive adult individuals that become part of the plankton. Linking both sexes of a monstrillid species is difficult because individuals of both sexes and members of different species can be collected together as planktonic adults. The Brazilian species Cymbasoma rochai Suárez-Morales & Dias, 2001, known from male specimens only, was recognized to have a strong resemblance to the nominal C. longispinosum , currently recognized as a well-defined species-group (Suárez-Morales, 2011). Hence, it was expectable that the female C. rochai would also resemble the species of the C. longispinosum species-group. Plankton surveys in Brazilian coastal areas yielded records of several female individuals reported as Cymbasoma cf. longispinosum. It is presumed that these are the females of C. rochai. The hitherto unknown female of C. rochai is herein described as such, and in addition revealed and described as a member of the widespread C. longispinosum species-group, now containing 11 species worldwide. This is the first confirmed record of a member of this group from Brazil and also the first known male of this species-group. Resumen: Los copépodos monstrilloides son parásitos proteleanos de invertebrados marinos bentónicos; sus etapas juveniles son completamente endoparásitas y emergen del huésped como individuos adultos reproductores de vida libre que se convierten en parte del plancton. Vincular ambos sexos de una especie de monstriloide es difícil porque individuos de ambos sexos y miembros de diferentes especies se pueden recolectar juntos como adultos planctónicos. Se reconoció que la especie brasileña Cymbasoma rochai Suárez-Morales & Dias, 2001, conocida solo por especímenes machos, tenía un gran parecido con el C. longispinosum nominal, actualmente reconocido como un grupo de especies bien definido. Por lo tanto, era esperable que la hembra C. rochai también se pareciera a la especie del grupo de especies C. longispinosum. Los estudios del plancton en las zonas costeras de Brasil generaron registros de varias hembras reportadas como Cymbasoma cf. longispinosum Se presume que estas son las hembras de C. rochai. Se describe la hembra previamente desconocida de C. rochai y se revela como el más reciente miembro del grupo de especies C. longispinosum , que ahora contiene 11 especies en todo el mundo. Este es el primer registro confirmado de un miembro de este grupo de Brasil y es el primer macho reconocido en este grupo de especies. [ABSTRACT FROM AUTHOR]

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Introduction: The tomopterids are holopelagic polychaetes widely distributed in all oceans, nevertheless they have been poorly studied despite their important implications in the trophic webs, as predators of various groups of zooplankton, including eggs and fish larvae. Objective: To describe the structure of the community of these pelagic worms in an upwelling area in the Central American Pacific. Methods: The zooplankton samples were obtained during the oceanographic campaign DOMO IV organized by the Universidad Nacional Autónoma de Mexico, in July-August, 1982. The polychaetes of the Tomopteridae family were sorted out and identified providing data on their specific composition, abundance and distribution. Results: Four species of the genus Tomopteris were determined, being T. elegans and T. planktonis dominant, T. nationalis constant and T. euchaeta rare. T. nationalis, T. elegans and T. euchaeta have tropical and subtropical affinies, while T. planktonis have been considered as cosmopolitan species. T. elegans had the higher relative abundance (62%) and T. euchaeta the lower (2.5%). Conclusion: Overall, T. elegans and T. planktonis showed a notable rise in the abundance related to upwelling in the thermal dome of Costa Rica. [ABSTRACT FROM AUTHOR]

Se analizó la composición y abundancia del zooplancton de la laguna El Morro en la isla de Margarita, Venezuela, durante el periodo de surgencia (marzo-mayo 2011) y de relajación (junio-agosto 2011). Las muestras fueron recolectadas en 6 estaciones de las diferentes zonas de la laguna. Se realizaron calados con una red de plancton de 333 µm durante 10 minutos. Se midió in situ la temperatura, salinidad y oxígeno disuelto, además de nutrientes. Se registraron valores medios de temperatura de 29.7 ºC, salinidad de 36 ups, oxígeno disuelto de 5.9 mg.L-1. La concentración de nutrientes fue baja (medias de 0.12; 0.04; 0.03 mg.L-1 para nitrato, nitrito y fosfato, respectivamente). Se detectaron diferencias significativas temporales con mayores registros en la temporada de relajación, mientras que espacialmente no mostró diferencias, a pesar que en las estaciones internas (Est. 4,5,6) se obtuvo mayor abundancia. Se identificaron quince grupos zooplanctónicos, determinándose nueve especies del grupo Copepoda, dos de Cladocera, una de Decapoda, Tunicada y Rotifera y diferentes formas larvarias de distintos taxa. Las larvas de crustáceos presentaron la abundancia media y relativa más alta (47738 ind.m-3 y 46.83%, respectivamente), seguido del copépodo Oithona nana (31740 ind.m-3 y 25.94%, respectivamente) y Paracalanus quasimodo (12958 ind.m-3 y 8.47%, respectivamente). Esta laguna involucra la estacionalidad surgencia-relajación como un efecto importante en la distribución y abundancia del zooplancton.

Abstract The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second with moderate chlorophyll and nutrients concentration and moderate daphnids percentage; high species number and a third site with high chlorophyll and nutrients concentration, high daphnids percentage and high species number. Daphnids increase under mesotrophic status, agree with similar results observed for southern Argentinean and New Zealand lakes.

RESUMO Poças temporárias são importantes ampliadores da biodiversidade local, sobretudo em áreas florestadas estacionais. Alterações na cobertura vegetal ao longo das margens desses corpos hídricos podem alterar a composição e estrutura da sua comunidade zooplanctônica. Nesse sentindo, testamos a hipótese de que a presença de mata ripária altera a estrutura da comunidade zooplanctônica encontrada em poças temporárias. Foram filtrados até 10 litros de água, em malha de 20 µm, em poças com (CM) e sem mata ripária (SM), e coletados dados de clorofila-α e as variáveis limnológicas. Todos os espécimes foram identificados com microscópio óptico em câmara de Sedgewick-Rafter. Os dados foram tratados quanto à composição e estrutura da comunidade (riqueza, frequência, abundância relativa e biomassa), sendo realizadas análises de diversidade (Série de Hill), de correspondência canônica (ACC) e de espécies indicadoras (IndVal). Diferenças significativas foram observadas entre as variáveis limnológicas nas duas condições, principalmente nos parâmetros de turbidez, sólidos totais dissolvidos e clorofila-α, as quais mostraram maior influência sobre a estrutura da comunidade. Embora a diversidade e biomassa de rotíferos tenham sido superiores nas poças SM, a riqueza e a biomassa de cladóceros foi superior nas poças CM. A análise de espécies indicadoras demonstrou que alguns rotíferos e microcrustáceos, como Ceriodaphinia cornuta G. O. Sars, 1885, Notodiaptomus cearenses Wright, 1936 e Ostracoda morf.2 são indicativos de poças CM, enquanto outras espécies indicam ambientes com maior turbidez (poças CM), por exemplo Polyarthra vulgaris Carlin, 1943 e Diaphanosoma spinulosum Herbst, 1975. Os resultados sugerem uma diferenciação expressiva entre os ambientes com e sem vegetação ripária, mostrando sua importância na estrutura da comunidade, reforçando a necessidade de medidas protetivas para ambientes temporários, visto que são essenciais para a manutenção da biodiversidade local.

La producción primaria (PPr) es la energía fijada por los organismos autótrofos. En los ecosistemas acuáticos, se produce principalmente mediante procesos fotosintéticos realizados por algas planctónicas o bentónicas y macrófitas. En La Pampa, la ecología de las lagunas ha comenzado a ser estudiada recientemente, pero no hay una referencia inadecuada de PPr algal y cómo está influenciada por el zooplancton. Dado que los lagos poco profundos en La Pampa son diferentes de los ampliamente estudiados en la provincia de Buenos Aires, el objetivo de esta contribución fue determinar el PPr fitoplanctónico de una laguna orgánica turbia poco profunda del noreste de La Pampa, y la influencia del zooplancton en su valor. La PPr se estimó 6 veces a lo largo del día con la técnica de oxígeno disuelto, utilizando botellas claras y oscuras. Para probar el efecto del zooplancton en las estimaciones de PPr, comparamos PPr con y sin zooplancton, que se eliminó con una malla de 40 micrones. Se registró una mayor concentración de nutrientes que los típicos lagos someros pampásicos de la provincia de Buenos Aires, el fitoplacton estuvo dominada por Chlorophyta y el ensamblaje de zooplancton fue típico de ambientes de baja salinidad. Las densidades de zooplancton se redujeron durante las horas del mediodía a la tarde, lo que podría indicar un importante proceso de migración del zooplancton. La PPr neta fue similar a la detectada en lagos en una ubicación latitudinal similar, pero la PPr máxima por la clorofila no fue mayor que la registrada en los lagos turbios orgánicos de la Provincia de Buenos Aires. El zooplancton tuvo una débil influencia en el PPr. Las determinaciones de los dos tratamientos no mostraron diferencias significativas, excepto a las 8 pm cuando el PPr neto sin zooplancton fue tres veces mayor que el tratamiento con zooplancton.

Investigamos las distribuciones verticales y horizontales de zooplancton en la zona litoral de un lago somero pampeano: laguna Lacombe (Buenos Aires, Argentina) durante las 24 horas del día en verano. Se empleó una nueva metodología que permite tomar múltiples muestras sin alteraciones ni dificultades para el muestreo de sectores con lechos de macrófitas sumergidas. Este lago se caracteriza por la presencia de ictiofauna litoral y planctívora. La laguna Lacombe exhibió alta transparencia debido a la presencia de macrófitas sumergidas (Myriophyllum quitense). Observamos poca variación a diferentes profundidades dentro de las transectas horizontales con respecto a la temperatura, la concentración de oxígeno disuelto, la conductividad y el pH, y registramos los gradientes de abundancia de zooplancton horizontales y verticales estadísticamente significativos (ANOVA). La mayoría del zooplancton de cuerpo pequeño (ciliados y rotíferos) no evidencia una variación significativa en su distribución horizontal o vertical. Los cladoceranos litorales parecen migrar verticalmente en lugar de horizontalmente, mientras que Diaphanosoma birgei exhibió cambios significativos en su distribución horizontal. La presencia de macrófitas emergentes y sumergidas en la zona litoral no es suficiente para promover diferencias claras en la migración diurna horizontal de zooplancton. Las diferencias en las fluctuaciones diarias de la especie en determinadas especies pueden depender principalmente de los requisitos ecológicos específicos, las condiciones ambientales y / o la depredación de los peces.

Don Tomás es un lago poco profundo urbano, turbio e hipereutrófico ubicado en el lado oeste de Santa Rosa. Debido a que tiene una importante población de pejerrey (Odontesthes bonariensis), este lago es importante para actividades recreativas y turísticas. Como se observaron muchos cambios en muchos parámetros limnológicos, incluida la composición y la abundancia del zooplancton entre 1995-96 y 2006, el objetivo principal de esta investigación fue comparar estos parámetros con los obtenidos de septiembre de 2008 a agosto de 2009. La salinidad disminuyó a lo largo de los tres períodos de 1.65 (1995-96) a 0.65 gl-1 (2008-09) debido principalmente a la escorrentía de la ciudad y al constante bombeo de agua para riego. La transparencia del agua también disminuyó de 0.24 (1995-96) a 0.14 m (2008-09). La riqueza total de zooplancton no cambió, pero se observaron cambios en la composición taxonómica cuando los grupos se analizaron por separado (la riqueza de cladoceros disminuyó y los rotíferos aumentaron durante 2006). La riqueza de cladoceros disminuyó de 9 especies en 1995-96 a 4 en 2006, a solo 2 especies en 2008 -2009. El mismo patrón se observó con la riqueza de copépodos que disminuyó de 4 especies en 2006 a solo 2 especies en 2008-09. Por otro lado, la riqueza de rotíferos aumentó de 8 especies (1995-96) a 15 (2008-2009 La disminución de la transparencia del agua pudo deberse a la falta de Daphnia (observada solo en 1995-96) y al aumento de la dominancia de los rotíferos. La abundancia total de zooplancton mostró importantes diferencias interanuales, siendo la más baja en 2006. Los resultados obtenidos revelan la gran variabilidad del zooplancton en este tipo de ambiente.

El objetivo de este estudio fue investigar los cambios ocurridos en la estructura y dinámica de la comunidad de zooplancton durante los trabajos de dragado realizados en el sector inferior del río Salado (Buenos Aires, Argentina). Las muestras se tomaron antes y durante la extracción de una restricción de río y la sustitución de un puente en un sitio aguas arriba y otro río abajo de esta modificación hidráulica. Los trabajos de dragado se realizaron durante el período de bajo nivel de agua. Las muestras de zooplancton se obtuvieron filtrando volúmenes de 10 l extraídos en tres puntos de una transecta en el canal del río (en ambas orillas y en la mitad del curso) durante 14 semanas (semanalmente de marzo a junio). Los parámetros físicos y químicos se midieron in situ con un multímetro. La conductividad disminuyó de 12,000 μS/cm (marzo-abril) a 6,000 μS/cm (abril-junio). Las combinaciones de zooplancton se correlacionaron con factores como la conductividad, la turbidez, la temperatura del agua y la densidad del fitoplancton. Los tintínidos (Tintinnidium fluviatile y Codonella cratera) prevalecieron con alta salinidad, mientras que los rotíferos (Brachionus plicatilis y Keratella tropica, entre otros) dominaron más tarde. Los microcrustáceos eran escasos en relación con la conductividad del río. Los sitios analizados mostraron una composición y abundancia similares de zooplancton durante todo el período de muestreo. Podemos suponer que los efectos de los trabajos de dragado en condiciones de poca agua causan perturbaciones mínimas en la corriente de la comunidad del zooplancton.

In central Argentina the alternation of cycles of rainfall above or below the historic mean is frequent; so, many saline lakes can dry or fill in a short time. As in La Pampa most of the studies on these lakes were limited to annual cycles, the information about variations under different climatic conditions is scarce. The aims of this study were to determine the limnological and zooplankton parameters of a semi-permanent Pampean saline lake during 2013 posterior to its filling after a drought, to compare the information with that obtained in 2007, because the two annual cycles had relatively different environmental characteristics and to test the hypotheses i) in 2013, after filling, scarce tolerant zooplankton species were recorded, replaced by more tolerant ones as salinity increased and ii) species richness in 2013 was greater than that recorded during higher hydrologic stability. Samples were taken between January and December of both years. In 2007 depth was stable and in 2013 it fluctuated markedly. The mean salinity was similar, close to 26 g/L. In 2007 it was stable, but in 2013 rose from 14.3 g/L (January) to 40.4 g/L (December). Transparency was the highest in 2007 (0.76 m ± 0.26) and the lowest in 2013 (0.17 m ± 0.05). The concentration of chlorophyll a in 2007 was lower ( (1.73 mg/ m3 ± 1.25) than in 2013 (38.16 mg/m3 ± 42.33). Species richness showed six species in 2007 and seven species in 2013. In 2007 crustaceans predominated, especially Boeckella poopoensis, but in 2013 rotifers dominated. Among them, Brachionus plicatilis and B. dimidiatus presented a maximum in autumn (1702 and 2062 ind/L, respectively). Daphnia menucoensis was absent during 2013 and the inverse correlation between the density of this cladoceran and chlorophyll a concentration could show its influence on water transparency because of its grazing on phytoplankton. The differences in limnological parameters allow us to know the variability of environmental conditions of a Pampean saline lake and to expand our knowledge about tolerance ranges of some endemic species as B. poopoensis and Moina eugeniae.

Diel vertical migration is a widely studied phenomenon occurring specially in marine and well stratified continental systems. The aim of this work was to study the spatial distribution of zooplankters in a «pampasic» shallow lake and to look for the existence of vertical migration. During summer 2002, replicated samples were taken during two 24 hintervals in the pelagic zone, using the 12 L Schindler-Patalas trap. Twenty-nine taxa were registered, corresponding 23 to Rotifera, 4 to Cladocera and 2 to Copepoda. The three groups considered in this work were generally located deeper when the water transparency was the highest. Maximum and minimum depths of residence were registered during light and dark hours, respectively. This probably indicates that changes in light could induce zooplankton movements. Although the vertical pattern observed in zooplankton populations from Los Padres Lake was similar to that of stratified lakes, with an ascending movement of individuals at dusk and a descending movement at dawn, it was not as pronounced as in deeper lakes. In order to obtain an explanation of the observed pattern, future work should deal with the description of spatial and temporal changes in abundance and availability of the resources.

In this paper we report a rare autumm phytoplankton bloom in a shallow lake of the semiarid Pampean area of Argentina. Phytoplankton biomass peaked only once during the autumn, followed 2 months later by a chlorophyll peak. The biomass peak might have been the result of a weak grazing pressure on the phytoplankton community (dominated by the nongrazeable Planktothrix agardhii (Gomont) Anagnostidis & Komárek) coupled with a reduction in the N-limitation towards the autumm. The chlorophyll peak took place when phytoplankton cells increased their chlorophyll content probably due to a reduction of solar irradiance and low water transparency. This findings indicate that phytoplankton seasonality in this particular area may depend on multiple biotic and abiotic factors. [ABSTRACT FROM AUTHOR]

Plankton samples obtained from the Ciénaga Grande de Santa Marta, an extensive estuarine system in northern Colombia, yielded adult male and female specimens of an undescribed halicyclopine cyclopid copepod of the genus Halicyclops. Cyclopid copepods are frequently found in freshwater and transitional habitats. Members of the subfamily Halicyclopinae are chiefly brackish water forms with a few freshwater species. The new species described herein is assignable to the group of species "F" of Halicyclops (sensu Pesce, 2018) with a 2333 exopodal spine formula. Currently, this group contains five species and one subspecies. Halicyclops gutierrezi sp. n. can be distinguished from its known congeners by the absence of an anal operculum, the relative length of setae of the female and male P5, the relative length of the inner setae of P4EXP3, and details of the male antennule. This is the fifth species of Halicyclops recorded from Colombia and the first one of Halicyclops group "F" described from the Caribbean region. With the addition of H. gutierrezi sp. n., the number of species of the genus known from the Neotropics increased to 20. A key to the species of the genus recorded in Colombia is also provided. [ABSTRACT FROM AUTHOR]