Triops cancriformis (Crustacea: Notostraca) occurs in ephemeral habitats like rain pools or floodplain pools distributed over a large geographical range. The named habitats are disturbed by human impacts and, consequently, T. cancriformis is endangered throughout its distribution range. In the present thesis the populated habitats and threats are characterised and further morphological and genetic variations detected among and within European populations are reported. On the basis of recent investigations it is shown that T. cancriformis subspecies separation is hampered by an individual variability which points to the necessity of species revision. The analysis of mitochondrial gene sequence data suggests that the species has colonised most of Europe very recently. The advantage of a complex reproductive strategy in T. cancriformis in this process is discussed. The population structure resolved with nuclear DNA markers highlights that there is low allelic diversity among and within populations compared to other Branchiopoda (Daphnia). By means of the present study it can be shown that habitat conservation is most important to protect T. cancriformis.

The role of the sandprawn, Callichirus (=Callianassa) kraussi (Stebbing), as an ecosystem engineer was assessed in the lower reach of the temporarily open/closed Kasouga Estuary situated along the Eastern Cape coastline of southern Africa over the period April 2010 to June 2011. The study comprised two distinct components, a field study and a caging experiment. The field study assessed the correlation between sand prawn densities and selected physico-chemical (organic content of the sediment and bioturbation) and biological (microphytobenthic algal concentrations and macrobenthic abundance and biomass) variables in 50 quadrants in the lower reach of the estuary. Densities of the sand prawn within the quadrants ranged from 0 to 156 ind m⁻² (mean = 37 ind m⁻²). There were no significant correlations between the densities of the sandprawn and the estimates of the organic content of the sediment and the abundance and biomass of the macrofauna (P > 0.05 in all cases). Numerical analyses failed to identify any effect of the sandprawn density on the macrofaunal community structure. The rate of bioturbation was, however, strongly correlated to the sand prawn density. Similarly, the microphytobenthic alga concentrations were significantly negatively correlated to the sand prawn densities ((P < 0.05). The absence of any distinct impact of the sandprawn on the macrobenthic community structure appeared to be related to their low densities in the lower reach of the estuary during the study. To better understand the role of the sandprawn as an ecosystem engineer, a caging experiment was conducted using inclusion and exclusion treatments (n= 5 for each treatment). Densities of the sandprawn in the inclusion treatments (80 ind m⁻²) were in the range of the natural densities within the estuary. The experiment was conducted over a period of 18 weeks in the lower reach of the estuary during summer. The presence of the sandprawn, C kraussi, contributed to a significant decrease in the microphytobenthic algal concentrations and the abundance and biomass of the macrofauna (P < 0.05 in all cases). The decrease in the microphytobenthic algal concentrations in the presence of the sandprawn appeared to be related to the res-suspension of the sediments (bioturbation) generated by the burrowing and feeding activities of the sandprawn. The observed decrease in macrofaunal abundances and biomass in the inclusion treatments appeared to be mediated by both the decreased food availability (mainly the microphytobenthic algae) and the burial of organisms within the sediments. Numerical analysis indicated that the sandprawn did, however, not contribute to a change in the species composition of the macrofauna. Results of the current study indicate that C.kraussi plays an important role in structuring the invertebrate community and energy flow within temporarily/open closed Kasouga Estuary.

ix, 119 leaves : ill., maps ; 28 cm Notes Typescript Thesis (Ph. D.)--University of Oregon, 1985 Includes vita and abstract Bibliography: leaves 108-119 Another copy on microfilm is located in Archives

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 77-80). Description: xii, 80 leaves : ill. ; 29 cm. / The lower distributional limits (fronts) of callianassid shrimp populations were observed at five sites in South Slough, Coos Bay estuary, Oregon. Fronts at four sites exhibited similar shoreward-seaward movements while the remaining site showed drastic population reductions. Shrimp density and body size were found to be significantly greater above than below the front. There was no consistent pattern found in grain size or interstitial water content across the front. In a controlled predator-exclusion experiment, resulting shrimp densities were not significantly different among treatments. Front shifts showed no pattern in response to treatments. These results imply that fish predation is not responsible for front placement. Trawls taken on both sides of the front produced similar densities of a predatory fish, Leptocottus armatus. Because predation pressure was calculated to be roughly equal above and below the front, Leptocottus is not expected to be responsible for position and movements of these fronts.

Made available in DSpace on 2014-12-17T15:01:45Z (GMT). No. of bitstreams: 1 IranML.pdf: 679853 bytes, checksum: 41b8ab13f1034bf3dbc30705bfdf84e4 (MD5) Previous issue date: 2008-04-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The objective of this scientific article is to introduce the opportunities of implementation of cleaner production (CP) in a shrimp culture farm. The methodology used for this was exploratory research implemented in a production unit located in the Northeast Brazil. The scientific article approaches since generic aspects of the technique about the management to use water, energy and the effluent characterization of this productive activity. It discusses quantitative aspects, environmental questions and chances of P+L during the productive process phases. The results points to input economy in the form of feed, soil correctives, medicines, and energy applied to the process, which range from 4% to 27%, emphasizing the small profit should be viewed as a source of considerable environment return. The authors conclude for the adoption property of this technique in this agribusiness segment, point out to the management importance of the input dosage in the quality of the final effluent, besides the adoption of a physical-chemistry remediation mechanism to the residual of Sodium metabissulphite used in the process of shrimp caught / O objetivo do trabalho ? apresentar uma estrat?gia de implementa??o da produ??o mais limpa (P+L) em uma fazenda de cultivo de camar?es. A metodologia utilizada foi pesquisa explorat?ria, realizada pela investiga??o via estudo de caso, implementada em uma unidade produtiva localizada no nordeste do Brasil. O trabalho aborda desde aspectos gen?ricos da t?cnica no que diz respeito ao gerenciamento do uso da ?gua, energia, e da caracteriza??o do efluente desta atividade produtiva. Discute aspectos quantitativos, considera??es ambientais, e oportunidades de P+L nas fases do processo produtivo. Os resultados apontam para economias de insumos sob a forma de alimentos, corretivos de solo, medicamentos, e energia aplicados ao processo, que variam de 4 a 27%, ressaltando-se que o pequeno ganho financeiro, deve ser encarado como uma fonte de consider?vel benef?cio ambiental. Os autores concluem pela propriedade da ado??o da t?cnica neste segmento do agroneg?cio, ressaltando a import?ncia do gerenciamento da dosagem de insumos na qualidade do efluente final, al?m da ado??o de um mecanismo de remedia??o f?sico-qu?mica para o residual de metabissulfito de s?dio utilizado na despesca

La population de la crevette blanche Palaemon longirostris, espèce résidente des estuaires faisant l’objet d’une pêche traditionnelle, est soumise à des forçages environnementaux (fluctuations naturelles du milieu, modifications du régime hydro-climatique de l’estuaire en lien avec le changement climatique) et anthropiques importants (aspiration dans les circuits du CNPE -Centre Nucléaire de production d’Electricité du Blayais-, pêche ciblée, pollutions etc.). Dans ce contexte et sur la base d’un suivi mensuel, réalisé depuis 1979, complété par des échantillonnages en 2007, cette thèse montre que cette population répond fortement aux changements environnementaux abiotiques et anthropiques. Ainsi, d’importantes fluctuations spatio-temporelles des abondances sont mises en évidence à diverses échelles temporelles, spatiales et biologiques. L’analyse de la série à long terme montre des fortes oscillations interannuelles régulières (période 5/10 ans) en partie liées aux facteurs environnementaux et aux variations du recrutement. Une diminution de l’abondance globale, ainsi qu’un déplacement vers l’amont de cette population, sont également constatés. Ce déclin est attribué aux fortes variations et nombreuses modifications des traits de vie de l’espèce –reproduction, -croissance, -mortalité, démontrées au cours de l’étude. La présence de déformations de l’exosquelette, étudiée aussi via un élevage de plusieurs mois, révèle par ailleurs, de forts impacts négatifs à l’échelle individuelle (mortalité). De plus, des simulations réalisées à partir d’un modèle matriciel de dynamique de population élaboré durant l’étude, montrent la synergie des pressions anthropiques par prélèvements (CNPE, pêche) et des forçages environnementaux, ainsi que l’importance des processus de déplacement dans le fonctionnement de cette population. Cette étude démontre finalement l’intérêt que revêt cette population et plus largement les populations de crevettes estuariennes, pour l’étude du fonctionnement et du diagnostic de l’état des écosystèmes estuariens. De nouvelles métriques originales sont proposées, lesquelles ouvrent vers la voie vers de nouveaux indicateurs. / The white shrimp, Palaemon longirostris, is an estuarine species and an important fishing resource. This species therefore encounters an important environmental forcing (natural fluctuations of the environment, modifications of the hydro-climatic regime of the estuary associated with the climate change) and an anthropological forcing (drawing up by the circuits of the CNPE - Nuclear center of electricity production of Blayais-, targeted fishing, pollutions etc.). In this context and on the basis of a monthly survey in place since 1979 and completed in 2007, this study shows that this population is strongly influenced by environmental and anthropological changes. Important spatio-temporal variations in the shrimp abundance are highlighted at different temporal, spatial and biological scales. A long-term analysis underlines strong regular interannual oscillations (5/10-year period) partially linked with environmental factors and recruitment variations. A decrease in the global abundance and a movement of this population towards the upstream part of the estuary are also displayed. In this study, the decline is attributed to strong variations and numerous modifications in the life history traits of the species - reproduction, - growth, - mortality. The presence of exoskeletal deformities, alternatively studied via a rearing of several months, reveals strong negative impacts at the individual scale (mortality). Furthermore, simulations based on a population-matrix model, developed during the study, show the synergy of the anthropological pressure by capture (CNPE, fishing) and the environmental forcing, as well as the importance of movement processes in the population dynamics. This study finally demonstrates the interest of this population, and more widely of the estuarine shrimp populations, in the understanding of the functioning and the diagnosis of the estuarine ecosystem state. New original metrics are proposed, opening the way towards new indicators.

Triops cancriformis (Crustacea: Notostraca) occurs in ephemeral habitats like rain pools or floodplain pools distributed over a large geographical range. The named habitats are disturbed by human impacts and, consequently, T. cancriformis is endangered throughout its distribution range. In the present thesis the populated habitats and threats are characterised and further morphological and genetic variations detected among and within European populations are reported. On the basis of recent investigations it is shown that T. cancriformis subspecies separation is hampered by an individual variability which points to the necessity of species revision. The analysis of mitochondrial gene sequence data suggests that the species has colonised most of Europe very recently. The advantage of a complex reproductive strategy in T. cancriformis in this process is discussed. The population structure resolved with nuclear DNA markers highlights that there is low allelic diversity among and within populations compared to other Branchiopoda (Daphnia). By means of the present study it can be shown that habitat conservation is most important to protect T. cancriformis.

Previous research regarding aquatic acidification has examined the protonation of the carbonate and does not consider calcium to be a limiting factor. This is the first study to suggest that pH may affect the uptake of calcium in crustacean gills. This project describes ion transport mechanisms present in the cell membranes of white river shrimp Litopenaeus setiferus gill epithelium, and the effects of pH on the uptake of calcium by these means. Partially purified membrane vesicles (PPMV) of shrimp gills were prepared through a homogenization process that has been used previously to define ion transport in crab and lobster gill tissues. In the current study, shrimp gill PPMV calcium uptake at 50 µM, and 250 µM was greatest at pH 7.0 (p=0.01, p=0.0001). A valinomycin/K+ induced membrane potential (PD) at pH 7.0 significantly increased (p=0.003) calcium uptake from that observed in the absence of a PD. An induced PD at pH 8.0 significantly increased (p=0.003) calcium uptake from that observed in the absence of a PD, however, was not significantly greater than uptake at pH 7.0 in the presence of a PD (p=0.05). Amiloride (2mM) treatments, and amiloride (2mM) + verapamil (100µM) cocktail treatments showed significant decrease in calcium uptake from the control (p=0.03), however, they were not different from each other. This indicates an electrogenic carrier with two driving forces: calcium concentration, and asymmetric exchange stoichiometry.