Calanoid copepods are abundant in South American inland waters and include widespread species, such as Boeckella gracilipes (Daday, 1902), which occurs from the Ecuador to Tierra del Fuego Island. This species occurs under various environmental conditions, and is found in oligotrophic lakes in Patagonia (39-54°S) and in shallow mountain lakes north of 39°S. The aim of the present study is to conduct a morphometric comparison of male specimens of B. titicacae collected in Titicaca and B. gracilipes collected in Riñihue lakes, with a third population of B. gracilipes collected in shallow ponds in Salar de Surire. Titicaca and Riñihue lakes are stable environments, whereas Salar de Surire is an extreme environment. These ponds present an extreme environment due to high exposure to solar radiation and high salinity levels. The results of the study revealed differences among the three populations. These results agree well with systematic descriptions in the literature on differences between the populations of Titicaca and Riñihue lakes, and population of Salar de Surire differs slightly from the other two populations. It is probable that the differences between the population of Salar de Surire and the other two populations result from the extreme environment in Salar de Surire. High exposure to solar radiation...
The Chilean saline lakes are distributed mainly in the Atacama desert in northern Chile and the southern Patagonian plains. The scarce studies are restricted mainly to northern Chilean saline lakes, and these revealed that the main component in these ecosystems are the halophylic copepod Boeckella poopoensis Marsh 1906, or the brine shrimp Artemia franciscana (Kellog, 1906), and both species do not coexist. The present study consisted of field observations in zooplankton assemblages in southern Chilean saline lakes (51-53 ºS). These first observations revealed three different patterns, one saline lake only with A. persimilis (Piccinelli and Prosdocimi, 1968), a second lake only with B. poopensis, and a third lake with A. persimilis, B. poopoensis and unidentified harpacticoid copepod. These results are different in comparison with the observations in the literature that described the non-coexistence between B. poopoensis with brine shrimps. Ecological and biogeographical topics were discussed.
The Chilean Patagonia has numerous kinds of inland water ecosystems such as lakes, ponds, wetlands and rivers that have been poorly studied due to access difficulties. This study was carried out in Aysen region, in southern Chile, and it included different kinds of water bodies such as rivers, streams, ponds, lagoons and lakes distributed along an altitudinal gradient at 46° S. It was found a low species number, essentially cladocerans, copepods and amphipods. A null model was applied in order to determine the existence of regulator factors of species associations, and the results revealed that they are not random. The patterns would be influenced by geographical and limnological characteristics of the studied sites. Our results would agree with regional studies on habitat heterogeneity such as in Torres del Paine National Park and other zones in Tierra del Fuego island.
Even though the Chilean lakes are characterized by their oligotrophy, a transition from oligotrophy to mesotrophy, due human intervention, has been reported in some lakes. Nevertheless, there are still some pristine and unpolluted small lakes and ponds in mountain zones, free of human intervention and surrounded by native forests. Nine unpolluted, oligotrophic and pristine water bodies located in Cañi Park, a mountain zone with altitudes between 1000 to 1500 m a.s.l and forests where Nothofagus dombeyi, N. pumilio and Araucaria araucana predominate, were studied. For each sampled lake, zooplankton was collected and environmental parameters were obtained (conductivity, total dissolved solids, and chlorophyll concentration). A null model of species co-occurrence was applied to determine randomness in species associations. All sites revealed low species richness (< 6); the calanoid copepod Boeckella gracilis Daday, 1902 was present in all sites. The results of the null model indicated randomness or absence of regulatory factors in species associations. Only few species occur in practically all localities. Also, a significant inverse association between chlorophyll concentration with percentage of calanoid copepods and a weak direct association between chlorophyll concentration and percentages of cladocerans were found.
Mycosporine-like amino acids (MAAs) were studied in zooplankton from 13 Argentinian lakes covering a broad range in altitude, maximum depth and physico-chemical properties of the water. Four to nine different MAAs (predominantly porphyra-334 and shinorine) were found in the copepods Boeckella gibbosa, B. gracilipes, B. meteoris and Parabroteas sarsi, and in the ciliate Stentor amethystinus, while MAAs were undetectable in the cladoceran Daphnia middendorffiana. Among the different copepods, maximum MAA concentrations accounted for 0.25–1.31% of the dry weight, and contents were generally about three to seven times (up to 43 times) higher in the animals living in the clearest lakes compared to those occurring in low-UV systems. This variability in the content of MAAs was related to the lake altitude (r2 = 0.71), and the fraction of the water column to which 1% of the surface UV radiation at 320 nm penetrated (r2 = 0.57). Our data therefore underscore the role of MAAs as sunscreens to decrease the potential negative effects of solar radiation, but they also indicate that other environmental factors besides UV transparency play a role in determining MAA concentrations. One lake was selected to obtain additional information on the qualitative composition of MAAs in seston of <100 μm between two sampling sites and over a 2 month study period (austral summer). Six different MAAs were detected in the samples...
Copepod systematists should be careful not to attribute taxonomic significance to teratological structures. Given that only a minute fraction of copepod populations is subjected to microscopic examination, and that several workers have encountered intersexual individuals, intersexuality is not an extremely rare phenomenon. The fifth legs of an intersexual Boeckella triarticulata, the second to be recorded in the literature, are figured and described in detail. The factor that induces intersexuality does not affect all four rami of the fifth pair of legs uniformly; one ramus may be fully male in character and another almost completely female. Karukinka fueguina Menu-Marque, 2003 is probably based on two intersexual individuals of Boeckella poppei (Mrázek, 1901).; Ian A.E. Bayly and Russell J. Shiel
Valid identification of species of freshwater zooplankton is the first step to understand population structures, abundance, and diversity in the pelagic environment. While some Australian taxa can be easily identified morphologically, e.g., Calamoecia ampulla (Searle, 1911), most other species of freshwater micrometazoans are difficult to identify without specialised training, resulting in limited and even incorrect identification of the various taxa. The use of DNA barcodes, for species identification and discrimination, has added a new dimension to the traditional phenotypic approach and allows researchers to understand the patterns of genetic variability and to overcome taxonomic difficulties in the identification of the species from different life history stages. We used mitochondrial gene cytochrome c oxidase I (COI) to examine the species status of common planktonic microcrustaceans in two South Australian reservoirs. COI analyses indicated that the zooplankton specimens examined from the order Diplostraca and the class Maxillopoda, which were assigned binomial names a priori from the genera Bosmina, Boeckella, Chydorus, Calamoecia and Daphnia, possessed distinct COI sequences and nested cohesively within the genealogy, except for individuals of Ceriodaphnia cf. cornuta and a Ceriodaphnia species complex that formed 4 clusters. These clusters were not explicitly identified morphologically. The present study does improve and contribute to the understanding of the status of taxonomy and biogeography of micro-crustaceans in South Australia. This information is crucial for the application of these species in studies of local and regional environmental change over varying time scales. We recommend the integration of traditional morphology with DNA barcoding-based examination...
The Chilean saline lakes are distributed mainly in the Atacama desert in northern Chile and the southern Patagonian plains. The scarce studies are restricted mainly to northern Chilean saline lakes, and these revealed that the main component in these ecosystems are the halophylic copepod Boeckella poopoensis Marsh 1906, or the brine shrimp Artemia franciscana (Kellog, 1906), and both species do not coexist. The present study consisted of field observations in zooplankton assemblages in southern Chilean saline lakes (51-53 °S). These first observations revealed three different patterns, one saline lake only with A. persimilis (Piccinelli and Prosdocimi, 1968), a second lake only with B. poopensis, and a third lake with A. persimilis, B. poopoensis and unidentified harpacticoid copepod. These results are different in comparison with the observations in the literature that described the non-coexistence between B. poopoensis with brine shrimps. Ecological and biogeographical topics were discussed.
The crustacean zooplankton of Chilean inland waters are characterized by abundant calanoid copepods, mainly from the genus Boeckella. The present study aims to update the distribution of Boeckella gracilis in the inland waters of the Araucania region (38-39°S) and to use null model analysis to understand the B. gracilis species associations. In the literature for Chile, this species is reported to be found in one northern lake and in three lakes of northern Patagonia. These findings are complemented by reports of this species for coastal and mountain ponds and mountain lakes of the Araucania region. These results agree with descriptions of this species for South American inland waters. The results of the null model analysis reveal factors regulating the species associations, whether comparing all the inhabitats or the guild structure, although some simulations show the opposite situation due to the presence of repeated species at many sites.; Los crustáceos zooplanctónicos en aguas continentales chilenas están caracterizados por la
abundancia de copépodos calanoideos, principalmente del género Boeckella. El objetivo del presente trabajo
es actualizar la distribución de esta especie en aguas continentales de la región de la Araucanía (38-39ºS)...
The water bodies studied herein are located in the Huerquehue National Park, a mountain zone with Nothofagus alpina, N. pumilio, N. dombeyi, and Araucaria araucana forests, at 700-1500 m a. s. l. There are numerous oligotrophic lakes, with characteristics similar to the deep Araucanian lakes. Many of these small lakes are difficult to reach, because the only routes leading there are long mountain paths. The sites studied in the present paper are five lakes: the first is located at the basis of the mountains (700 m a.s.l.) and is fed by a river that reaches it from series of three other lakes higher in the mountains (1300 m a.s.l.), which are connected by small streams. These four lakes are inhabited by fish populations. The fifth site is a small, shallow, and fishless pond located at one of the highest sites in the park (1400 m a.s.l). Samples were collected for analysis of chlorophyll concentrations and for littoral, aquatic crustaceans. All sites are oligotrophic, and show low crustacean species richness. In the four lakes with fishes, the crustacean littoral fauna was composed of Hyalella araucana (Amphipoda) only. In the fifth lake, the crustaceans collected were H. araucana, copepods (Boeckella gracilis and Mesocyclops longisetus)...
The calanoid copepod, Boeckella poopoensis Marsh, 1906 inhabits shallow saline ponds located in the Andes mountains in Argentina, Bolivia, Chile, and Peru, as well as in the plains of southern Argentina. The species is halophilic and can tolerate salinity levels of 1 to 90 ppt. This paper describes the relative abundance of the species in shallow mountain ponds in northern Chile from 23° to 27°S. A direct correlation was observed between salinity and the relative abundance of B. poopoensis (r2 = 0.4139), and between 45 and 90 ppt S the species was found to be dominant in zooplankton assemblages. Crustacean species richness at the sites studied showed a significant, inverse trend with salinity (r2 = 0.7329), and this trend became even stronger (r2 = 0.7681) when data previously published for the Bolivian Andean plateau were included. Ecological and biogeographical issues related with these results are discussed.
In Andes Mountains (14-27°S) and Patagonian plains (45-53°S) in Chile, there are numerous shallow saline and sub-saline lakes. These water bodies have important temporal and spatial variation of their salinity caused by mineral composition of their watershed or exposition to arid weather. In this study we compared the salinity level and the occurrence of centropagid copepods (Crustacea, Copepoda, Calanoida) in water bodies of both regions. In the Andes Mts the calanoids inhabit water bodies of salinity lower than 90 g l -1, and the representative species was Boeckella poopoensis (Marsh 1906), that occurs between 5.0 to 90.0 g l-1. In Patagonian plains, the copepods occur at salinity level between 0.1 to 16.0 g l-1, and within these values most frequent are B. popei (Mrázek 1901) and Parabroteas sarsi (Mrázek 1901). Both species can coexist with other calanoid species.
The increase in penetration of ultraviolet radiation has been reported currently over southern South America. It would affect the photoprotective responses in biotic elements of freshwater ecosystems. An experiment was designed using pigmented adult individuals of the species Daphnia dadayana (Paggi 1999), Boeckella antiqua (Menu-Marque & Balseiro 2000), and Parabroteas sarsi (Mrázek 1901), characteristic for shallow fishless ponds from South American plains (located between 41 and 53°S latitude). The artificial ultraviolet radiation was involved in the experiment, with two levels of dissolved organic carbon (DOC), which would exert a protective effect against ultraviolet radiation. The results of this experiment showed that under conditions of low DOC concentrations, D. dadayana recorded a higher mortality, while under low DOC concentrations, B. antiqua and P. sarsi were not affected by ultraviolet radiation. Daphnids would be less tolerant to the exposure to ultraviolet radiation than pigmented calanoid copepods.
La diversidad del zooplankton en lagos salinos poco profundos de Sudamérica es baja y su
distribución depende altamente de la salinidad, la cual varía de moderada a alta. A salinidades
menores a 90 g/l predomina el copépodo halofílico Boeckella poopoensis (Marsh, 1906), mientras
que a salinidades superiores a ese nivel, el anostraco Artemia franciscana (Kellogg, 1912) es el
componente exclusivo de los hábitats. Esto constituye sin embargo una información parcial. En una
revisión de la literatura disponible para lagos salinos Andinos en Bolivia, Chile y Perú se confirma
que la presencia y distribución de ambas especies está significativamente regulada por el nivel de la
salinidad. Los resultados del modelo nulo de co-ocurrencia de especies indican que las asociaciones
de especies no son aleatorias, y estos resultados están respaldados por el análisis de correlación,
el cual indica una relación inversa significativa entre número de especies con salinidad, y hubo
relaciones directas significativas entre número de especies con la superficie del hábitat. El bajo número de especies que es característico de estos hábitats y su dependencia con los cambios de salinidad efectuado por las condiciones climáticas provee un buen modelo de sistema de monitoreo
de cambios climáticos.; Zooplankton diversity in shallow salt lakes of the Andean countries in South America is low and
distribution is highly dependent on salinity...
Los copépodos calanoideos son abundantes en los ensambles zooplanctónicos de aguas continentales de la Patagonia, y en este contexto, se analizaron parámetros de fertilidad en cuatro especies de calanoideos representativos de aguas continentales de la Patagonia (37°-52° S) con el objetivo de determinar los parámetros de fertilidad en poblaciones de copépodos representativas de la Patagonia chilena. Para este propósito se consideraron dos a cuatro poblaciones de las siguientes especies: Boeckella gracilipes, B. michaelseni, B. poppei, y Tumeodiaptomus diabolicus, se consideraron individuos hembras con huevos a las que se midió el largo total, número de huevos y la razón entre número de huevos con el largo total. Los resultados mostraron que a nivel de especies B. poppei fueron significativamente diferentes para las otras tres especies. A nivel de poblaciones, se encontraron diferencias a nivel de poblaciones en algunas especies. Los resultados que los parámetros reproductivos variaron en función de los parámetros ambientales variaron en función de las condiciones ambientales de las poblaciones y estaría asociado con las condiciones ecológicas tales como estructuras poblacionales y las propiedades de las comunidades zooplanctónicas.; The calanoids copepods are abundant in zooplankton assemblages in Patagonian inland waters...
Los cuerpos de agua de Chile se caracterizan por la presencia de tramas tróficas sencillas (De los Ríos-Escalante, 2003) y un bajo número de especies zooplanctonicas, siendo dominante los copépodos calanoideos, específicamente los géneros Boeckella y Tumeodiaptomus, ocurriendo el proceso contrario con los Cladoceros, los cuales son especies dominantes en el hemisferio norte (Soto & Zúñiga, 1991; Gilloly & Dodson, 2000; Dodson et al 2009).