Metridia lucens and M. pacifica previously have been differentiated primarily by the structure of the male fifth legs. lucens originally was described to have one large spine on the inner margin of the fourth segment and M. pacifica to have two spines, one each on the third and fourth joints. Some authors have reported M. lucens with two so-called spines on the same segment and M. pacifica also with two such spines but located together on the fourth segment. This led to M. pacifica being questioned as a species by certain authors who claimed it synonymous with M. lucens. In the present study, M. lucens from the Northwestern Atlantic is compared with M. pacifica from the Northeastern Pacific and differences in size and structure are evident to separate them. The fifth pair of legs on adult males and females were examined and findings indicated errors in the original descriptions of both species. Another Metridia population, found in the coastal waters of British Columbia, was compared with the described species. It was found to be similar to M. lucens and could be, in part, the reason for the past confusion between the Atlantic and Pacific species. / Science, Faculty of / Zoology, Department of / Graduate

The abundance and microspatial distribution of harpacticoid copepods were studied from Jan 1977 to Jan 1980 at two intertidal sites on the Fraser River Delta, B.C.: one (Sand) on the crest of a sand wave and the other (Mud) on the edge of its muddy trough. Eight species formed the communities at the two sites. The composition of the communities was studied by biweekly survey in 1978. Longer term changes in the organization of the sand community were followed by annual mid-winter surveys over four years. Factor analysis was used to group species with similar patterns of seasonal occurrence and macrohabitat distributions. Microspatial patterns in the two communities were compared by heterogeneity chi-square analysis from random core samples collected monthly. The distribution of species relative to small-scale hydraulic bedforms (sand ripples) was studied at the sand site. Distinct patterns of community organization were seen at the two sites. The mud community was characterized by high temporal overlap of species; the sand species showed a distinctive pattern of temporal segregation. Although species in both communities were segregated at small spatial scales, microspatial partitioning was stronger and seasonally more variable in the mud. Spatial patterns in the sand were related to the rippled bedforms. Biogenic structuring by macrobenthos and disturbance by predators were implicated as the causes of microspatial patterns observed in the mud community in summer. Although the two communities showed distinct features of organization they were not completely isolated. Two mud species, Scottolana canadensis and Tachidius triangularis, 'migrated' to the sand in summer. The role of biological interactions in structuring the communities was investigated. Predation by small tidepool fish, Clevelandia ios and Leptocottus armatus, was studied by gut analysis. Predation was species- and size-selective, with two epipelic species, S. canadensis and T. triangularis, occurring most frequently in fish gut samples. A morphometric basis for ontogenetic variation in predation by C. ios was proposed. Evidence to support the hypothesis that competitive interactions help to structure harpacticoid copepod communities was found in changing patterns of abundance, changing patterns of microhabitat use and morphometric character displacement over four years. Competitive interactions were highly dynamic and appeared to be part of the cause of both the temporal and microspatial segregation observed in the sand community in 1979. By 1980, the eight species present in the January sand community formed a displacement series in body sizes. Although each harpacticoid community is unique, numerous parallels exist between the structure and function of the Iona North assemblage and those from shallow water habitats, worldwide. It is clear, therefore, that the conclusions from this research have more than local significance. / Science, Faculty of / Zoology, Department of / Graduate

Ph.D. / Female adult specimens of Lamproglena clariae attach to gill filaments of freshwater fish of the family Clariidae, penetrate the gill tissue and consume blood. Previously, studies have been done on the taxonomy of this parasite, but little research has been published on biological aspects. Hence, it was the aim of this study to determine and record L. clariae’s aspects of biology such as ecology, life cycle and pathology. The study was conducted through both field and laboratory observations with specimens collected from the Vaal Dam and Vaal River Barrage. A positive correlation was observed between the host's physical dimensions and the size of the parasite, parasites from both sites preferred the fourth gill and the median part of the gill arch for attachment. There was no significant host gender preference by parasites. Three free living nauplius stages, four copepodite, a cyclopoid and adult stages were recorded as life stages of this parasite. Observations suggested that development of larval stages of L. clariae is influenced by both photoperiod and temperatures. Furthermore low infestation success of the experimental fish was observed. This parasite caused localised infestation as varying degrees of swelling of gill filaments were observed only in the vicinity of its attachment site. Histological examination revealed epithelial hyperplasia, resulting in fusion of gill lamellae and necrosis of the host tissue in the vicinity of the parasite. No correlation exists between the infestation intensity and fish haematocrit values. Although L. clariae causes localized infestation, high intensity of infestation may be detrimental to the fish. Hyperplasia of epithelial tissue resulting in fusion of lamellae would result in restriction of oxygen passage and thus hinder the process of respiration of the host. / Prof. A. Avenant-Oldewage

No description available.

No description available.

Este es el primer trabajo sobre copépodos meiobentónicos marinos realizado en el estuario de Bahía Blanca, y es el único trabajo sobre este grupo zoológico realizado en la Argentina desde 1982. El material examinado provino en su totalidad de la localidad de Arroyo Pareja, que se encuentra en la costa norte del estuario de Bahía Blanca. Esta playa se ubica a 38° 54’ 48,26” de latitud Sur y 62° 4’ 25,55” longitud Oeste, en la parte más externa de la porción media del estuario. El sustrato es limoso-arcilloso con valores promedio de 87 % de lodo y 13 % de arena. Se realizaron doce campañas entre el 9 de abril de 2014 y el 19 de marzo de 2015, tomando cinco muestras de sedimento cada vez, a partir de las cuales se registró el número de ejemplares adultos del orden Harpacticoida. Paralelamente, en cada campaña, se midieron tres variables físico-químicas con un multisensor HORIBA U10: temperatura, pH y salinidad. El análisis morfológico arrojó como resultado la identificación de 13 morfotipos pertenecientes al orden Harpacticoida. De ellos, se describieron tres especies nuevas para la ciencia durante el curso de esta investigación: Halectinosoma parejae Sciberras, Huys, Bulnes & Cazzaniga, 2017 (Ectinosomatidae), Ilyophilus sp. nov. (Nannopodidae; aún inédita) y Quinquelaophonte aestuarii Sciberras, Bulnes & Cazzaniga, 2014 (Laophontidae). Halectinosoma parejae fue numéricamente dominante en la mayoría de los muestreos y por este motivo, su identificación fue prioritaria. Pertenece a un género con numerosas especies nominales, muchas de ellas insuficientemente descritas, otras que son especies dudosas y muchas asignadas erróneamente. Se elaboró una clave dicotómica de las especies del género Halectinosoma con una fórmula setal diferente a la condición plesiomórfica. Por otro lado, la consulta de toda la bibliografía mundial sobre este género y el examen de material tipo permitieron elaborar una clave actualizada de los géneros de la familia Ectinosomatidae y también aclarar la posición taxonómica de varias especies problemáticas como Pseudobradya lanceta, Halectinosoma spinicauda, H. pterinum, H. paraspinicauda, H. littorale, H. arenicola y H. smirnovi. Halectinosoma parejae, Ilyophilus sp. nov. y Quinquelaophonte aestuarii, junto con otras dos especies de la familia Miraciidae aún no determinadas completamente, dominan la taxocenosis en términos de abundancia, constituyendo el 94 % del total de ejemplares recolectados. Está en desarrollo el estudio taxonómico de las dos morfoespecies de Miraciidae —una de ellas del género nominal polifilético Delavalia Brady, 1868—, así como de las ocho entidades numéricamente minoritarias. La densidad de los harpacticoideos intersticiales estudiados en esta tesis estuvo en el orden de magnitud usual para los barros de marismas. Se cumplió el patrón usual de inequitatividad, en el que una especie, en este caso Halectinosoma parejae, es la dominante principal y con unas pocas especies subdominantes se completa más del 90 % de los individuos de la taxocenosis. Se corroboró el patrón temporal de los harpacticoideos de mayor abundancia en los meses cálidos, aunque también se registró un pico menor de abundancia en invierno. Halectinosoma parejae incluyó hembras ovígeras en todas las fechas de muestreo en las que estuvo presente. Delavalia sp. e Ilyophilus sp. nov. también tuvieron períodos prolongados de reproducción, pero con una proporción de ovígeras mucho más alta en verano, mientras que la especie aún no identificada de Miraciidae parece concentrar su reproducción en invierno. / This is the first contribution on meiobenthic marine copepods of Bahía Blanca estuary, and this is the only work on this group since 1982. The material was collected from Arroyo Pareja, a locality located on the north shore of the Bahía Blanca estuary. This beach is located at 38°54´48.26´´ and 62°4´25.55´´, in the most external part of the middle portion of the estuary. The substrate is silty-clayey with average values of 87 % mud and 13 % sand. Twelve campaigns were carried out between April 9, 2014 and March 19, 2015, and five samples were taken of sediment each time. The number of harpacticoid adults was recorded. At the same time, three physical-chemical variables were measured with a HORIBA U10 multisensor: temperature, pH and salinity. From the morphological analysis, 13 morphotypes belonging to Harpacticoida were found, of which three new species were described: Halectinosoma parejae Sciberras, Huys, Bulnes & Cazzaniga, 2017 (Ectinosomatidae), Ilyophilus sp. nov. (Nannopodidae; aún inédita) and Quinquelaophonte aestuarii Sciberras, Bulnes & Cazzaniga, 2014 (Laophontidae). Halectinosoma parejae was numerically dominant in most samples, so its identification was a priority. It belongs to a genus with several nominal species, many of them insufficiently described, others are dubious species and many of them were wrongly assigned. A key to the species of Halectinosoma displaying a setal formula other than the common plesiomorphic condition is provided. The revision of the world bibliography and examination of type material allowed to elaborate an updated key to all genera in family Ectinosomatidae and to clarify the taxonomic position of several problematic species such as Pseudobradya lanceta, Halectinosoma spinicauda, H. pterinum, H. paraspinicauda, H. littorale, H. arenicola and H. smirnovi. Halectinosoma parejae, Ilyophilus sp. nov. and Quinquelaophonte aestuarii, together with two other species of the family Miraciidae not yet fully determined, dominate the taxocenosis in terms of abundance, constituting 94% of the total collected specimens. The taxonomic study of the two morphospecies of Miraciidae —one of them belonging to the polyphyletic genus Delavalia Brady, 1868— is under development, as well as the study of the eight numerically minority entities. Density of the interstitial harpacticoids studied in this work was in the usual order of magnitude for marsh muds. Results matched the usual pattern of inequality, in which one species, here Halectinosoma parejae, is dominant and more than 90 % of the taxocenosis is arisen with a few subdominant species. A temporal pattern of higher abundance in warm months was corroborated, although a lower peak of abundance was recorded in winter. Halectinosoma parejae presented ovigerous females on every sampling date in which it was present. Delavalia sp. and Ilyophilus sp. nov. also have long breeding periods thought with a much higher proportion of ovigerous females in summer, while the unidentified species of Miraciidae seemed to limit its reproduction to winter.

Wong, Lik Chi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 96-108). / Abstracts in English and Chinese. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.iii / Acknowledgements --- p.V / Table of Contents --- p.vi / List of Tables --- p.viii / List of Figures --- p.ix / Chapter Chapter 1. --- General introduction --- p.1 / Chapter Chapter 2. --- "Seasonal and spatial variations of phytoplankton size composition in Tolo Harbour and Tolo Channel, Hong Kong" --- p.3 / Chapter 2.1 --- Literature Review --- p.3 / Chapter 2.2 --- Introduction --- p.6 / Chapter 2.3 --- Materials and methods --- p.8 / Chapter 2.4 --- Results --- p.11 / Chapter 2.5 --- Discussion --- p.32 / Chapter 2.6 --- Conclusion --- p.37 / Chapter Chapter 3. --- "Seasonal and spatial variations of primary production and copepod production in Tolo Harbour and Tolo Channel, Hong Kong" --- p.38 / Chapter 3.1 --- Literature review --- p.38 / Chapter 3.1.1 --- Factors affecting primary production --- p.38 / Chapter 3.1.2 --- Factors affecting copepod production --- p.40 / Chapter 3.1.3 --- Marine food chain --- p.42 / Chapter 3.2 --- Introduction --- p.45 / Chapter 3.3 --- Materials and methods --- p.48 / Chapter 3.3.1 --- Primary production --- p.48 / Chapter 3.3.2 --- Copepod production --- p.50 / Chapter 3.3.3 --- Density of Noctiluca scintillans --- p.53 / Chapter 3.4 --- Results --- p.54 / Chapter 3.5 --- Discussion --- p.78 / Chapter 3.5.1 --- Primary production in Tolo Harbour --- p.78 / Chapter 3.5.2 --- Copepod production in Tolo Harbour --- p.82 / Chapter 3.5.3 --- Transfer efficiency in Tolo Harbour --- p.89 / Chapter 3.6 --- Conclusion --- p.92 / Chapter Chapter 4. --- General conclusion --- p.93 / References --- p.96

Copepod species are distributed throughout the ocean by many factors, including chemical, biological, and physical effects. Turbulence in the ocean has been suggested as a factor that vertically partitions some species of copepod. Copepods may seek calmer waters by sinking to deeper levels as the surface waters become more turbulent, or may maintain their position in turbulent waters. The goal of this study is to determine the behavioral effects of turbulence on three species of copepod, Calanus finmarchicus, Acartia tonsa, and Temora longicornis. Experiments consisted of exposing each of the species to stagnant water plus four levels of turbulence intensity. The experiments were conducted in a laboratory apparatus that mimics oceanic turbulence. The turbulence characteristics have been previously characterized by particle image velocimetry (PIV), that show the turbulence to be nearly isotropic and homogeneous in the observation region. Behavior responses were quantified via several measures, including the number of animals phototactically aggregating per minute, the number of escape events, the swimming speed, and the net-to-gross-displacement ratio. There are important conclusions about the effect of laboratory turbulence on copepods. The size of the copepod has a significant effect on its aggregation and swimming capability with increasing turbulence. The smaller copepods had less ability to overcome a strong flow field, and they were more likely to be advected by the stronger flow fields. Swim style also can influence how a copepod reacts to increased turbulence. If the copepod is a hop and sink traveler, then the copepod continues to hop and sink more than its cruising counterparts as turbulence increases. The cruise and sink travelers did not alter the number of escapes in response to turbulence.

Nos sistemas lacustres, ocorrem diferenças naturais entre os compartimentos limnético e litorâneo num mesmo lago (hábitats, recurso trófico, ciclos biogeoquímicos e processos hidrológicos) e entre lagos que se encontram em regiões de diferentes coberturas vegetais. Tais diferenças podem determinar variações na diversidade zooplanctônica e nas características químicas e físicas da água. Pelo presente trabalho objetivou-se verificar a ocorrência destas diferenças entre as regiões limnética e litorânea de cinco lagoas (Carioca, Aguapé, Águas Claras, Ariranha e Amarela)pertencentes ao sistema de lagos do Vale do Rio Doce (MG), além de uma comparação destes resultados com os diferentes tipos de vegetação que ocorrem no entorno.Situado a sudoeste do estado de Minas Gerais, o sistema de lagos do Vale do Rio Doce é composto, principalmente, por dois tipos de vegetação terrestre: a floresta secundária de Mata Atlântica que está restrita ao Parque Estadual do Rio Doce; e o cultivo de eucalipto que ocupa grande área da região. As lagoas abordadas no presente estudo foram reunidas em três grupos distintos, segundo o tipo de vegetação que ocorre no seu entorno: lagoa Carioca (floresta de Mata Atlântica); lagoas Aguapé e Águas Claras (cultivo de eucalipto com manejo mais intensivo e com freqüente retirada de espécies nativas do sub-bosque); e lagoas Ariranha e Amarela (cultivo de eucalipto com presença de sub-bosque de espécies nativas da Mata Atlântica). Foram realizadas amostragens nos períodos climáticos de inverno de 1999 (estiagem) e verão de 2000 (chuvas), para as variáveis físicas e químicas da água e para a comunidade zooplanctônica. Pelos resultados obtidos, ficaram claras as diferenças entre os compartimentos limnético e litorâneo em função das variáveis físicas e químicas no período de inverno de 1999, e em função da riqueza de espécies zooplanctônicas em ambos os períodos climáticos estudados. A principal diferença da riqueza de espécies entre os compartimentos foi devida ao maior número de táxons na região litorânea, em função da ocorrência de espécies da família Chydoridae e Macrothricidae (Cladocera), e da família Lecanidae (Rotifera). Por outro lado, não ficaram evidentes as diferenças entre os grupos de lagoas segundo a vegetação do entorno, em função das variáveis limnológicas e dos indicadores de diversidade. Ainda assim, é importante destacar as diferenças entre a lagoa Carioca para as demais lagoas, principalmente, em relação ao seu maior grau de trofia e menor disponibilidade de habitats litorâneos, que determinam uma menor riqueza de espécies. Assim, na lagoa Carioca não ocorreram organismos filtradores e herbívoros pertencentes aos Cladocera, com exceção da espécie Diaphanosona birgei . Foi possível verificar também que as espécies de Copepoda Cyclopoida Thermocyclops minutus e Tropocyclops prasinus ocuparam preferencialmente as regiões limnéticas das lagoas, enquanto que Mesocyclops brasilianus ocorreu de forma mais marcante na litorânea. De forma geral, foi possível verificar que os tipos de vegetação não determinaram diferenças nas condições limnológicas e na diversidade zooplanctônica, uma vez que não se observaram padrões semelhantes nos valores das variáveis analisadas dentro de cada grupo de lagoas. / In lacustrine systems there are natural differences among the limnetic and littoral region in the same lake (habitat, food resources, biogeochemical cycles and hydrological processes) as well as between lakes that are located in regions with different vegetation cover. Such differences can determine defferences in the physical and chemical characteristics of the water as well as in the zooplankton diversity. The present work had the objective of verify the existence of these differences among limnetic and littoral region of five lakes (Carioca, Aguapé, Águas Claras, Ariranha e Amarela) belonging to the ake system of Rio Doce Valley (MG), and to analyse these results regarding the different vegetation cover existing in the lake surroundings. Located at the Southeast of Minas Gerais State, the Rio Doce Valley Lake System is covered by two main types of vegetation: secondary atlantic forest, restricted to the area of the State Park of Rio Doce, and Eucalyptus plantation covering the largest portion of the region. The lakes analysed in the present study were grouped in three distinct categories, according to the type of plant coverage in the surroundings: lake Carioca (atlantic forest); lakes Aguapé and Águas Claras ( Eucalyptus, without native forest layer) and lakes Ariranha and Amarela (mixed formation of Eucalyptus and native forest species). Samplig was carried out in the winter (dry period) of 1999 and summer (wet period) of 2000, for both physical and chemical water analysis and zooplankton community studies. There were clear differences among limnetic and littoral regions, regarding physical and chemical characteristics in the winter, and regarding zooplankton richness in both, dry and wet seasons. Major differences in species richness among these compartments were determined by the large number of taxa found in the littoral region, particularly due to the occurrence of species of Chydoridae and Macrothricidae (Cladocera) and Lecanidae (Rotifera). On the other hand, differences among the groups of lakes, according to the type of plant cover around the lake, were not evident, considering the limnological variables and diversity indices. There were, nevertheless, differences between Lake Carioca and the other lakes, mainly related to its higher trophic state, which combined with a small littoral development determines a low zooplankton species richness. Thus, in Lake Carioca filter-feeding Cladocera does not occur, except for Diaphanosoma birgei. It was also possible to verify that the species of Copepoda Cyclopoida Thermocyclops minutus, and Tropocyclops prasinus preferentiatly occupied the limnetic region of the lakes, whereas Mesocyclops brasilianus had a marked occurrence in the littoral region. In general, it was possible to conclude that the type of plant covering did not influence limnological conditions and zooplankton diversity since it was not possible to find a pattern regarding the variables here analysed, if considering those group of lakes.

Os Copepoda constituem a maior classe de pequenos crustáceos, com mais de 8.500 espécies descritas. Dentre as cinco ordens de Copepoda de vida livre, as espécies pertencentes à ordem Calanoida apresentam um forte endemismo, com uma restrita distribuição geográfica. Além disso, os Copepoda Calanoida são particularmente sensíveis a contaminantes contidos na coluna de água devido ao seu hábito planctônico. No presente trabalho foram realizados estudos ecotoxicológicos com duas espécies de Copepoda Calanoida, particularmente com as espécies Argyrodiaptomus furcatus Sars, 1901 e Notodiaptomus iheringi Wright, 1935. Estas espécies foram comparadas com relação à sensibilidade e desempenho como organismos-teste na avaliação da qualidade da água em ecossistemas de água doce. Foram testadas e adaptadas metodologias de cultivo em laboratório, e foram estudados os principais aspectos da biologia destes em condições ambientais controladas. Além disso, foram analisados aspectos referentes à dinâmica populacional. A sensibilidade das duas espécies de Calanoida às substâncias de referência sódio, potássio e zinco na forma de cloreto (\'NA\'CL\', \'K\'CL\' e \'ZN\'CL IND.2\', respectivamente), ao dicromato de potássio (\'K IND.2\'CR IND.2\'O IND.7\') e ao sulfato de alumínio (\'AL IND.2\'(\'SO IND.4\')IND.3\'), aos surfactantes dodecilsulfato de sódio (\'C IND.12\'H IND.25\'NA\'O IND.4\'S\') e ácido dodecil benzenosulfonato de sódio (\'CH IND.3\'(\'CH IND.2\')IND.11\'C IND.6\'H IND.4\'S\'O IND.3\'NA\'), foram avaliadas. Além disso, avaliou-se a toxicidade aguda de diferentes amostras ambientais e das toxinas da cianobactéria Microcystis aeruginosa após tratamento por irradiação. Os resultados dos testes ecotoxicológicos foram expressos em concentração efetiva (CE(I)50). Para o cálculo estatístico da CE50 foi utilizado o programa Trimmed Spearman-Karber. Os resultados relativos ao ciclo de vida mostraram que N. iheringi tem um menor tempo de desenvolvimento do que A. furcatus, com tempos de duração do desenvolvimento do ovo determinados pelos métodos indireto e direto. Verificou-se que a espécie de N. iheringi, de menor tamanho, apresentou tempo de desenvolvimento pós-embrionário menor do que a espécie de maior tamanho, A. furcatus. As taxas intrínsecas de crescimento populacional foram mais elevadas para a espécie A. furcatus do que para N. iheringi. Pelos resultados obtidos observou-se que N. iheringi além de atingir tamanhos menores, possui um desenvolvimento mais rápido e ciclo de vida mais curto. Em relação à sensibilidade destes Copepoda Calanoida às substâncias tóxicas observou-se que em relação aos sais, estas duas espécies foram mais sensíveis ao cloreto de potássio (\'K\'CL\'). Em relação aos metais, o grau de toxicidade aos Copepoda decresceu na sequência zinco > cromo > alumínio. Já com em relação aos surfactantes, a espécie N. iheringi foi mais sensível do que A. furcatus, e a toxicidade diminui à medida que o estágio de desenvolvimento dos indivíduos se torna mais avançado. Os náuplios são mais sensíveis à maioria das substâncias de referência testadas (sais, surfactantes, cromo e zinco) do que os estágios de desenvolvimento mais avançados. A espécie N. iheringi é mais sensível aos diversos agentes tóxicos do que a espécie A. furcatus, no entanto, N. iheringi foi mais resistente às cianotoxinas do que A. furcatus. Os resultados apresentados corroboram a idéia de que os calanoides A. furcatus e N. iheringi apresentam elevada sensibilidade a uma variedade de substâncias tóxicas de referência, o que torna viável sua utilização como organismos-teste em ensaios ecotoxicológicos. Estes estudos podem proporcionar maior entendimento sobre a estrutura das comunidades aquáticas e das alterações na dinâmica das populações, no sentido de se poder verificar como as espécies respondem às alterações na qualidade da água e o porquê das modificações na estrutura das comunidades, permitindo, dessa forma, ações de manejo e de conservação visando a preservação da biodiversidade das águas doces. / Copepods constitute the largest class of small crustaceans, with more than 8,500 described species. Among the five orders of free-living copepods, the species belonging to the order Calanoida show strong endemism, with a restricted geographic distribution. Additionally, they are particularly sensitive to contaminants in the water column due to their planktonic habit. In the present study ecotoxicological studies with two species of Calanoida copepods were performed, particularly with the species Argyrodiaptomus furcatus Sars, 1901 and Notodiaptomus iheringi Wright, 1935. These species were compared for sensitivity and performance as test organisms in assessing water quality in freshwater ecosystems. Methods of cultivation in the laboratory were tested and adapted, and the main aspects of these species biology were studied under controlled temperature and photoperiod. In addition, aspects related to population dynamics were also analyzed. The sensitivity of the calanoids to a number of reference substances as: sodium, potassium and zinc in the form of chlorides (\'NA\'CL\', \'K\'CL\' and \'ZN\'CL IND.2\', respectively), potassium dichromate (\'K IND.2\'CR IND.2\'O IND.7\') and aluminum sulfate (\'AL IND.2\'(\'SO IND.4\')IND.3\'), and to the surfactant sodium dodecyl sulfate (\'C IND.12\'H IND.25\'NA\'O IND.4\'S\') and sodium dodecyl benzenesulphonate (\'CH IND.3\'(\'CH IND.2\')IND.11\'C IND.6\'H IND.4\'SO IND.3\'NA\') were evaluated. Also the toxicity of environmental samples and of the cyanobacteria Microcystis aeruginosa toxin after irradiation treatment was tested. The results of ecotoxicity tests were expressed as effective concentrations (EC(I)50). The statistical calculation of the EC50 was carried out by the Trimmed Spearman-Karber program. The results regarding the copepods life cycle showed that N. iheringi has a shorter development time and duration of egg development, by both indirect and direct methods, than A. furcatus. It was found that small sized N. iheringi, had a post-embryonic development faster than the larger species, A. furcatus. The intrinsic rates of population increase were higher for the species A. furcatus than for N. iheringi. The results indicated that N. iheringi besides reaching smaller sizes, has a faster development and shorter life cycle. Regarding the sensitivity of these two species to toxic substances it was observed that in relation to the salts the calanoids were more sensitive to the potassium chloride (\'K\'CL\'). Compared to metals, toxicity to copepods followed the sequence zinc> chromium> aluminum. However, regarding surfactants the species N. iheringi was more sensitive than A. furcatus, and toxicity decreased with the advance in developmental stages. The nauplii were more sensitive to most of the reference substances tested (salts, surfactants, chromium and zinc) than the more advanced developmental stages. The species N. iheringi was more sensitive to various toxic agents than A. furcatus, but N. iheringi was more resistant to the cyanotoxins than A. furcatus. The results support the hypothesis that the calanoid copepods A. furcatus and N. iheringi have high sensitivity to a variety of toxic reference substances, what makes them feasible to be used as test organisms in ecotoxicological tests. The study performed may provide further understanding about the structure of aquatic communities and changes in population dynamics, contributing for the understanding of how species respond to changes in water quality by changes in community structure, subsidizing management actions aiming the conservation of freshwater biodiversity.