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Los organismos zooplanctónicos constituyen un eslabón importante en las redes tróficas de los cuerpos de agua, lo cual los convierte en indicadores útiles al evalúar el estado ecológico de un ambiente. En la presente tesis se estudió la estructura y dinámica del zooplancton de la laguna La Salada en relación a las variables físico-químicas, climáticas y al manejo antrópico. La Salada es una laguna salina somera, ubicada al SW de la provincia de Buenos Aires. Se caracteriza por presentar un importante manejo antrópico, recibiendo agua desde canales de riego derivados del Río Colorado. Se encuentra localizada en una región templada, semiárida y de fuertes vientos. Durante octubre 2012 y septiembre 2015, se realizaron mediciones cualitativas y cuantitativas del zooplancton y de las variables físico-químicas del agua a escala mensual en la laguna. A su vez se instaló una boya multiparamétrica a fin de medir variables limnológicas y meteorológicas en alta frecuencia. Se realizó una caracterización ambiental de la laguna y se estudió la variabilidad climática a partir del análisis de 50 años de registros meteorológicos diarios. La tendencia histórica muestra un aumento en 0,7 ºC de la temperatura del aire desde el año 1966 hasta el año 2015. A partir del análisis de las precipitaciones se clasificó al año 2012 como un período de lluvia normal, el año 2013 como un período muy seco, y los años 2014 y 2015 como años húmedos. Evidentemente la zona presenta una variabilidad climática importante. Del estudio de las variables limnológicas se determinó que se trata de una laguna mesosalina (30,4 g L-1) y alcalina (8,2), caracterizada por una transparencia elevada durante todo el período de estudio (166 cm). Su estado trófico se define como mesotrófico-eutrófico, con baja concentración de clorofila a en comparación con otras lagunas pampeanas (8,5 μg L-1), pero similares a otras lagunas salinas de la región y el mundo. La salinidad disminuyó y la concentración de nutrientes aumentó significativamente con el ingreso de agua aportada por los canales derivados del Río Colorado. La variación estacional de la temperatura desempeñó un rol importante, modulando las variaciones en la concentración de clorofila a. A partir de las mediciones de alta frecuencia se detectaron procesos importantes de interacción agua-atmósfera a escalas diurna, semidiurna y horaria. Dichas variaciones observadas en la temperatura del aire, humedad relativa, velocidad del viento, concentración de oxígeno disuelto y temperatura del agua, se asociaron con eventos de brisa local generados por las diferencias de temperatura y presión entre la laguna y el continente. Por otro lado, las mediciones de alta frecuencia de la concentración de oxígeno sugirieron que La Salada es un ecosistema con metabolismo autotrófico. Los valores de metabolismo fluctuaron dentro de los esperados para una laguna salina, siendo más productiva que otras lagunas templadas. La temperatura y las fluctuaciones en la conductividad juegan un importante rol en las características físico-químicas y biológicas del sistema. A su vez, la variación anual e interanual del nivel del agua es un factor crucial en el desarrollo de los procesos ecológicos en la laguna. El zooplancton de la laguna La Salada se caracterizó por presentar una diversidad baja, compuesto por especies halófilas y de pequeño porte, con una dominancia de rotíferos durante todo el período de estudio. El zooplancton estuvo dominado por B. plicatilis, seguido por otro rotífero de menor tamaño, S. kitina. El copépodo ciclopoideo Apocyclops sp. se halló principalmente en verano. La dominancia de los rotíferos y el hecho de que las abundancias de los copépodos (mayormente ciclopoideos) fueran bajas, es característico de ambientes eutróficos sujetos a una gran fuerza de predación por peces omnívoros (Odonthesthes sp). Los copépodos calanoideos estuvieron representados por B. poopoensis, una especie típica de lagunas salinas. Por otro lado, el hecho de que las especies predominantes son de pequeño porte y que los copépodos se encuentran representados por estadíos nauplii y juveniles en su mayoría, puede ser el resultado de la alta variabilidad ambiental, con un corto tiempo de retención e importantes fluctuaciones en las condiciones físico-químicas en respuesta a cambios en el nivel del agua debido al manejo antrópico. Las abundancias y biomasas del zooplancton mostraron respuestas interanuales distintas en relación a las principales variables físico-químicas. La dinámica de la abundancia zooplanctónica estuvo regulada por los cambios estacionales de temperatura. La biomasa zooplanctónica estuvo regulada por la el efecto de la entrada de agua y los aumentos consecutivos de las concentraciones de nutrientes y disminución de la conductividad/salinidad asociadas al manejo antrópico y por la temperatura. En conclusión, la presencia de peces zooplanctívoros en conjunto con los cambios en la concentración de nutrientes y salinidad, moldearon la comunidad zooplanctónica de la laguna La Salada hacia una de baja diversidad, conformada por especies halotolerantes y de pequeño porte. Esta presentó cambios característicos en la composición y biomasa en respuesta al manejo antrópico de la laguna. La variación anual e interanual del nivel del agua generada por la acción antrópica resultó ser un factor crucial en el desarrollo de los procesos ecológicos en La Salada. / Zooplankton organisms constitute an important link in the trophic networks of water bodies and are useful indicators of the overall ecological state of an environment. In the present thesis, the structure and dynamics of the zooplankton of La Salada lake were studied in relation to physicochemical and climatic variables subjected to anthropic management. La Salada is a saline shallow lake, located in the SW of the province of Buenos Aires. It is characterized by presenting an important anthropic management system, receiving water from irrigation channels derived from the Colorado River. It is located in a template, semiarid and windy region. From October 2012 to September 2015, the lake was surveyed with monthly frequency for qualitative and quantitative measurements of zooplankton and physicochemical variables. Also, a multi-parameter buoy was installed to collect high frequency limnological and meteorological data. The lake was characterized through limnological data and climate variability was assessed through daily meteorological records recorded during 50 years. The historical trend shows an increase in air temperature of 0.7 °C from 1966 to 2015. From the analysis of precipitation records, 2012 was classified as a normal precipitation period, 2013 as a very dry period, whereas the period 2014 and 2015 was considered wet. Clearly, the area is subject to an important climatic variability. Limnological variables measured in the lake indicated mesosaline (30.4 g L-1) and alkaline (8.2) conditions, with high transparency (166 cm) during the entire study period. The trophic state of the lake was defined as mesotrophic-eutrophic, with lower concentrations of chlorophyll a (8.5 μg L-1) compared to other Pampean lakes, but nevertheless similar to saline lakes of the same region and of the world. Salinity decreased and nutrients concentrations increased significantly due to the water inflow from channels derived from the Colorado River. Temperature seasonal variations played an important role modulating the chlorophyll a concentration. The analysis of high frequency measurements of several air and water parameters showed up the interaction water-atmosphere at short time scales, diurnal, semidiurnal and hourly. Variations in air temperature, relative humidity, wind speed, dissolved oxygen concentration and water temperature were associated with local breeze events generated by differences in temperature and pressure between the lake and the continent. On the other hand, the analysis of high frequency oxygen concentration measurements showed up a predominant autotrophic metabolism in La Salada. Metabolism values were within those expected for saline lakes, being more productive than other temperate lakes. Fluctuations in temperature and conductivity play an important role in the physicochemical and biological characteristics of the system. In turn, the annual and inter-annual variation of the water level is a crucial factor in the development of the ecological processes in the lake. The zooplankton of La Salada was characterized by a low diversity, represented by small size, halophiles species, with rotifers dominating the entire study period. The zooplankton was dominated by B. plicatilis, followed by another small rotifer, S. kitina. The cyclopoid copepod Apocyclops sp. occurred mainly in summer. The dominance of the rotifers and the fact that the abundances of the copepods were low, being represented mainly by cyclopoids, is characteristic of eutrophic systems under predation pressure by omnivorous fish (Odonthesthes sp.). Calanoids were represented by B. poopoensis, a typical species of saline lakes. On the other hand, the small size species and that the copepods were mainly represented by nauplii and juvenile stages may be the result of an adaptive process to high environmental fluctuation, such as the short retention time and the important fluctuations in physicochemical conditions in response to changes in the water level due to anthropic management. The abundances and biomasses of zooplankton showed different responses to the main physicochemical variables between years. The dynamics of zooplankton abundance was regulated by seasonal changes in temperature. Zooplankton biomass was regulated by the effect of water inflow and the subsequent increase of nutrient concentrations and decrease in conductivity/salinity associated with anthropogenic management and temperature fluctuations. In conclusion, the presence of zooplanctivorous fish together with the changes in the concentration of nutrients and salinity, shaped the zooplankton community of La Salada lake towards one of low diversity, constituted by small and halotolerant species. Changes in zooplankton composition and biomass in response to anthropic management of the lake were also recorded. The annual and inter-annual variation of the water level due to anthropic management proved to be a crucial factor in the development of the ecological processes in La Salada lake.

Acidic atmospheric deposition and acidification of soil and water on the Earth's surface, due to emissions of sulfur and nitrogen into the atmosphere, have led to drastic changes in the composition of surface waters and their biota in many regions of the world over the last century. The number of species and biomass of phytoplankton, zooplankton and benthos were reduced, or some components (zooplankton, zoobenthos, fish) became extinct. In the Jizera Mountains (Northern Bohemia, Czech Republic), the man-made acidification has always been combined with a natural acidity (dystrophy) of waters, caused by a high amount of organic acids. Despite a strong recovery of water chemistry from acidification, that has started in the 1990s, biological recovery is delayed and much more complex. This master thesis is a study of the succession of zooplankton (crustaceans) in mountain reservoirs Souš, Bedřichov and Josefův Důl after decades of strong acidification. Biological recovery from acidification has been in progress differently in the drinking water reservoir Souš, which has long been limed, in the Bedřichov reservoir with naturally high content of organic material, and in the drinking water reservoir Josefův Důl, which is the largest and deepest one and which was most affected by acidification. Recovery of...

Ostracodes, bi-valved crustaceans, are potentially excellent proxies for salinity.They are abundant, react to changes in salinity, and secrete low-magnesium calcite shells that preserve information about their host water chemistry. Changes in valve trace element concentration, stable isotope composition, and sieve pore shape values have been linked to changes in salinity. This study analyzed the response of the euryhaline ostracode, Cyprideis americana, to salinity in six lakes from two Bahamian islands across two seasons. The purpose of this work was to determine which compositional and morphological variables in C. americana are the most useful for paleosalinity reconstructions.Ostracode and water samples were collected from lakes of varying water chemistry on San Salvador Island (winter and summer seasons), and Exuma (winter season). Dissolved oxygen, pH, salinity, and temperature measurements were taken for each lake. The best-preserved valves from each lake were analyzed for sieve pore circularity, Mg and Ca concentrations, and δ18 O isotopic composition. Mg/Ca ratios and Kd[Mg] values were calculated for each lake. Each parameter was plotted against salinity for all of the lakes and for lakes from each season and island. Only the samples collected during the summer followed expected trends: with increases in lake water salinity, Mg/Ca ratio decreased, δ18 O composition increased, and sieve pore circularity decreased. Samples collected from the winter field sessions did not follow expected trends, potentially due to the breeding and moulting habits of C. americana. Temperature was more correlative with valve composition than a previous study of C. americana suggests, but is supportive of similar correlations of Cyprideis species in continental and other island settings. The valve Mg/Ca ratio and mean sieve pore circularity showed the best correlation with salinity and are the variables that will be most useful in paleosalinity studies from sediment cores. Future work should further investigate the relationship between mean sieve pore circularity and lake salinity as well as the breeding and moulting habits of C. americana. Such work may allow for past salinity ranges to be reconstructed from fossil C. americana samples.

The Summer (May through August) community of crustacean zooplankton and zebra mussel (Dreissena polvmorpha) larvae at a 15 m sample site in Lake Michigan near Michigan City was evaluated for the years 1990 through 1994. Yearly mean densities were compared with investigations done at the same sample location by Johnson (1972) and Ball State University (unpublished data) during 1970 and 1971, respectively to investigate possible changes in community composition during the past 25 years. Potential declines in crustacean zooplankton relating to the 1991 introduction of the filter-feeding zebra mussel were also evaluated.Overall declines in major species since 1970-71 included Bosmina longirostris, Daphnia retrocurva, and Diacyclops thomasi. Recent increases in the nearshore fish population of alewife (Alosa pseudoharengus) and spottail shiner (Notropis hudsonius) may have influenced the densities of these species in recent years. Copepod nauplii were the only crustaceans to increase in overall abundance since the period of 1970-71, as the number of invertebrate predators appeared to decrease. Other species did not show any noticeable change in long-term abundance or during the 1990-94 period.Zebra mussel larvae were first observed in the zooplankton complex studied on June 17, 1991. -Densities of larvae reached maximal levels for the period of study in 1994 with two large reproductive pulses of 195,000 and 210,000/m3 in June and August, respectively. The mean abundance during 1994 made up 65% of the total crustacean zooplankton/zebra mussel community complex. Evaluation of the vertical stratification of zebra mussel larvae in 1994 revealed a strong (r2=0.75, p<0.0005) tendency for veligers to remain in the upper 10 m of the water column due to thermal stratification. / Department of Biology

Zooplankton samples collected May through August, 1990 to 1996 at site M, 15 m depth in the Indiana waters of Lake Michigan were examined for microcrustaceans, rotifers, and zebra mussel (Dreissena polymorpha) veligers. Abundance numbers per m3 were combined with Coffman's (1995) data to quantify recent trends in the zooplankton.Rotifers dominated the community, with Polyarthra vulgaris, Colurella, Keratella crassa, and K. cochlearis the most prevalent species. Copepods, primarily nauplii and copepodid forms, were the next most abundant taxa. Except for 1994 and 1995, Cladocera abundance was higher than zebra mussel veliger abundance. The cladoceran assemblage was dominated by Bosmina Iongirostris, with very few Daphnia noted. A precipitous decrease in zebra mussels veligers from 1994 to 1996 warrants further investigation to determine the nature and the extent of the population decline.Regression analysis of zebra mussel veliger abundance against abiotic and biotic factors demonstrated veligers varied directly with rotifer abundance and water column temperature and indirectly with cladoceran and yellow perch (Perca flavescens) abundance. A similar regression model of rotifer abundance revealed direct correlation with calanoid, cladoceran, zebra mussel veliger, and yellow perch abundance. / Department of Biology

This research was conducted to provide baseline data on the population dynamics of microcrustacean zooplankton at Prairie Creek Reservoir in Delaware County, Indiana from 24 January 1996 to 30 December 1996. This lake is a shallow lake (average depth <8m) used for recreational fishing and water supply for the local community. No published studies of zooplankton have previously been conducted at this location. I intended to test the hypothesis that Prairie Creek Reservoir has the same microcrustacean populations of shallow lakes in this region. The findings were compared to other studies in several North American lakes and reservoirs. Biotic and abiotic factors were considered as related to the population dynamics of zooplankton. Zooplankton serve as a critical forage base for many fish species, including several of economic importance. Increases and changes in species composition of zooplankton organisms associated with eutrophic conditions may also be an indication of deteriorating water quality (Gannon 1972). The data from this research suggest that Prairie Creek Reservoir has the typical zooplankton populations of a shallow, eutrophic North American lake. The presence of relatively high numbers of organisms generally associated with eutrophic environments, such as Bosmina longirostris, Leptodiaptomus siciloides, Acanthocyclops vernalis, and others supports this idea. The data from this study will be helpful to fisheries and environmental managers and will provide a baseline for future studies. / Department of Biology

Orientador: Antonio Leão Castilho / Banca: Gustavo Monteiro Teixeira / Banca: Rogério Caetano da Costa / Resumo: Rimapenaeus constrictus apresenta ampla distribuição geográfica e os fatores ambientais que modulam o seu padrão de abundância e distribuição ainda são pouco entendidos. Os objetivos do presente estudo foram descrever os fatores ambientais atuantes sobre a região de Cananéia e compreender de maneira mais clara a influência da condição ambiental sobre a espécie R. constrictus. Os camarões foram obtidos a partir de coletas mensais na região de Cananéia, litoral sul do estado de São Paulo, de julho de 2012 a maio de 2014 com um barco camaroneiro equipado com redes do tipo double-rig, em isóbatas de 5 a 20 metros de profundidade. Os fatores ambientais foram obtidos na coluna d'água por meio de uma sonda Multiparâmetros e o sedimento com um pegador de Petersen. Foram coletados 1784 indivíduos distribuídos majoritariamente em salinidades acima de 30, em tipos de sedimento variáveis, desde silte + argila até areia grossa, em faixas de temperatura que variaram entre 17 e 29°C e nas menores concentrações de clorofila (até 14μg/L). Os fatores ambientais que mais influenciaram a distribuição da espécie foram salinidade e temperatura (Regressão Múltipla, p < 0,05). A abundância não diferiu entre as estações do ano, mas diferiu entre as estações amostrais (Tukey, p < 0,05). Cananéia apresentou-se como uma região dinâmica de características ambientais complexas. Rimapenaeus constrictus parece ser uma espécie bastante generalista em relação à escolha do substrato e, provavelmente, possui fisiologia do tipo euritermal e estenohalina, sendo a salinidade um fator considerado como limitante a sua distribuição / Abstract: Rimapenaeus constrictus presents a wide geographical distribution and environmental factors that influence their abundance and distribution pattern are still poorly understood. The aims of the present study were describe the environmental factors acting in Cananeia region and understand more clearly the influence of the environmental conditions on the R. constrictus. The shrimps were collected from monthly samples in Cananéia region, South coast of São Paulo state, from July 2012 through May 2014 using a shrimp boat outfitted with double-rig nets, at isobaths in 5 to 20 feet deep. Environmental factors were obtained in the water column by a Multiparameters probe and the sediment by a Petersen grab. Were collected 1784 individuals mainly distributed in salinities higher than 30 and variable types of sediment, since silt + clay until very coarse sandy, in temperatures ranging between 17 and 29°C and in the lower clorophyll concentrations (up to 14μg/L). The environmental factors that influenced the distribution of the species were salinity and temperature (Multiple Regression, p < 0.05). The abundance did not differ among the seasons, but differed among stations (Tukey, p < 0.05). Cananéia was presented as a dynamic region of complex environmental characteristics. Rimapenaeus constrictus seems to be a very generalist species in the choice of substrate and probably it has physiology eurythermal and stenohaline, and salinity was considered as a limiting factor in its distribution / Mestre

Made available in DSpace on 2015-10-06T13:03:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-27. Added 1 bitstream(s) on 2015-10-06T13:19:00Z : No. of bitstreams: 1 000847832_20160101.pdf: 795628 bytes, checksum: dc7ab7c34c4e568f8149aaff50b7139b (MD5) Bitstreams deleted on 2016-01-04T10:26:45Z: 000847832_20160101.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:36Z : No. of bitstreams: 1 000847832.pdf: 1734370 bytes, checksum: d8de76a485cd8158f641035d73cd6bec (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Rimapenaeus constrictus apresenta ampla distribuição geográfica e os fatores ambientais que modulam o seu padrão de abundância e distribuição ainda são pouco entendidos. Os objetivos do presente estudo foram descrever os fatores ambientais atuantes sobre a região de Cananéia e compreender de maneira mais clara a influência da condição ambiental sobre a espécie R. constrictus. Os camarões foram obtidos a partir de coletas mensais na região de Cananéia, litoral sul do estado de São Paulo, de julho de 2012 a maio de 2014 com um barco camaroneiro equipado com redes do tipo double-rig, em isóbatas de 5 a 20 metros de profundidade. Os fatores ambientais foram obtidos na coluna d'água por meio de uma sonda Multiparâmetros e o sedimento com um pegador de Petersen. Foram coletados 1784 indivíduos distribuídos majoritariamente em salinidades acima de 30, em tipos de sedimento variáveis, desde silte + argila até areia grossa, em faixas de temperatura que variaram entre 17 e 29°C e nas menores concentrações de clorofila (até 14μg/L). Os fatores ambientais que mais influenciaram a distribuição da espécie foram salinidade e temperatura (Regressão Múltipla, p < 0,05). A abundância não diferiu entre as estações do ano, mas diferiu entre as estações amostrais (Tukey, p < 0,05). Cananéia apresentou-se como uma região dinâmica de características ambientais complexas. Rimapenaeus constrictus parece ser uma espécie bastante generalista em relação à escolha do substrato e, provavelmente, possui fisiologia do tipo euritermal e estenohalina, sendo a salinidade um fator considerado como limitante a sua distribuição / Rimapenaeus constrictus presents a wide geographical distribution and environmental factors that influence their abundance and distribution pattern are still poorly understood. The aims of the present study were describe the environmental factors acting in Cananeia region and understand more clearly the influence of the environmental conditions on the R. constrictus. The shrimps were collected from monthly samples in Cananéia region, South coast of São Paulo state, from July 2012 through May 2014 using a shrimp boat outfitted with double-rig nets, at isobaths in 5 to 20 feet deep. Environmental factors were obtained in the water column by a Multiparameters probe and the sediment by a Petersen grab. Were collected 1784 individuals mainly distributed in salinities higher than 30 and variable types of sediment, since silt + clay until very coarse sandy, in temperatures ranging between 17 and 29°C and in the lower clorophyll concentrations (up to 14μg/L). The environmental factors that influenced the distribution of the species were salinity and temperature (Multiple Regression, p < 0.05). The abundance did not differ among the seasons, but differed among stations (Tukey, p < 0.05). Cananéia was presented as a dynamic region of complex environmental characteristics. Rimapenaeus constrictus seems to be a very generalist species in the choice of substrate and probably it has physiology eurythermal and stenohaline, and salinity was considered as a limiting factor in its distribution / FAPESP: 2013/14174-0