Neomysis integer (Leach) (Peracarida: Mysidacea) is a common component of the hyperbenthos of Western European estuaries, and this study focused on the ecophysiology and ecotoxicology of this mysid. Behavioural and physiological responses of N. integer to physical and chemical variables (current velocity, substratum type, temperature and salinity) were measured in the laboratory to gain better understanding of how this mysid maintains position in estuaries. Current velocity was the most important factor controlling position maintenance, and N. integer had a maximum swimming speed of c. 9cm sˉ¹. Position maintenance was facilitated by a muddy substratum and was not affected by salinity. Oxygen consumption and feeding rates of N. integer increased with increasing temperature but, whilst oxygen consumption decreased with increasing salinity, feeding rate increased. Male mysids consumed oxygen at a higher rate than females, however, there was no difference in the feeding rates of males and females. The acute toxicity of two organophosphate pesticides (chlorpyrifos and dimethoate) to N. integer was examined, and 96h LC50 values of 0.13µg chlorpyrifos Lˉ¹ and 0.54mg dimethoate Lˉ¹ were estimated. Sub-lethal exposure to chlorpyrifos led to an increased rate of oxygen consumption and decreased feeding rates compared with control animals. In addition, chlorpyrifos exposure led to disrupted behaviour of N. integer, including hyperactivity and decreased maximum swimming speed. The results are discussed in terms of the behaviour and physiology of N. integer in response to natural and anthropogenic physical and chemical variables in the natural environment. The potential of N. integer as a toxicity testing species, and the sublethal responses used in the study, are critically assessed.

Made available in DSpace on 2014-08-20T13:44:43Z (GMT). No. of bitstreams: 1 dissertacao_vanessa_neumann_silva.pdf: 455330 bytes, checksum: 2ef060bd7af461b93680757e9f1e471e (MD5) Previous issue date: 2009-01-12 / One of the main requirements for the assessment of the effect of seed refers to obtaining reliable results in a relatively short period of time, enabling the streamlining of decision-making. The objective of this study was to evaluate the efficiency of the electrical conductivity test, conducted with different structures of bean seeds (whole seed, cotyledons and embryonic axes), the separation of lots in levels of force, to check the possibility to obtain results in less time to 24 hours, to evaluate the efficiency of mass and individual methods and the results correlate with the emergence of seedlings in the field. We used seeds of the bean IAPAR 81, represented by four lots. The evaluation of the physiological quality of seeds was performed by the germination test, first count, classification of seedling vigor, accelerated aging, speed of protrusion of the root, emergence of seedlings in the field, leaching of potassium, calcium and magnesium, and studied methods for conducting the test, electrical conductivity, mass and individual with whole seeds, cotyledons and embryonic axes of bean. It was concluded that the electrical conductivity test conducted with embryonic axes is promising for evaluating the effect of bean seeds, is to determine the effect of bean seeds by the electrical conductivity test individual at a time, using embryonic axes the force of bean seeds can be determined by the electrical conductivity test mass in eight hours, using embryonic axes and in one hour with the cotyledons and embryonic axes are the structures that best express the reduction in force of bean seeds by the leaching of potassium, calcium and magnesium. / Uma das principais exigências para a avaliação do vigor de sementes refere-se à obtenção de resultados confiáveis em um período de tempo relativamente curto, permitindo a agilização das tomadas de decisões. O objetivo deste trabalho foi avaliar a eficiência do teste de condutividade elétrica, conduzido com diferentes estruturas de sementes de feijão (semente inteira, cotilédones e eixos embrionários), na separação de lotes em níveis de vigor, verificar a possibilidade de obter resultados em tempo inferior a 24 horas, avaliar a eficiência das metodologias massal e individual e correlacionar os resultados com a emergência de plântulas em campo. Utilizaram-se sementes de feijão da cultivar IAPAR 81, representadas por quatro lotes. A avaliação da qualidade fisiológica das sementes foi realizada através do teste de germinação, primeira contagem, classificação do vigor de plântulas, envelhecimento acelerado, velocidade de protrusão da raiz, emergência de plântulas em campo, lixiviação de potássio, cálcio e magnésio, sendo estudadas metodologias para condução do teste de condutividade elétrica, massal e individual com sementes inteiras, cotilédones e eixos embrionários de feijão. Concluiu-se que o teste de condutividade elétrica conduzido com eixos embrionários é promissor para a avaliação do vigor de sementes de feijão; É possível determinar o vigor de sementes de feijão pelo teste de condutividade elétrica individual em uma hora, utilizando eixos embrionários; O vigor de sementes de feijão pode ser determinado pelo teste de condutividade elétrica massal em oito horas, utilizando eixos embrionários e em uma hora com cotilédones e os eixos embrionários são as estruturas que melhor expressam a redução de vigor das sementes de feijão através da lixiviação de potássio, cálcio e magnésio.