Made available in DSpace on 2014-12-17T14:01:56Z (GMT). No. of bitstreams: 1 ViniciusPO.pdf: 1959283 bytes, checksum: a0ff605126178472baa83d52b610e562 (MD5) Previous issue date: 2007-12-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study evaluates the influence of depth and environmental parameters on the development of Gracilaria birdiae Plastino & Oliveira (Gracilariaceae Rhodophyta) in an organic shrimp pound (Litopenaeus vannamei) under euthrophical conditions. PVC structures (module) witch four ropes laden with 150 g of macroalgae each, were kept during 35 days at three different depths (surface, 10 and 20 cm depth). Wet biomass weighing and environmental parameters (temperature, salinity, turbidity, pH, transparence, precipitation, evaporation, insolation, accumulated solar radiation, nitrite, nitrate, ammonium and orthophosphate) were measured weekly. At all three proposed depths, the macroalgae displayed a higher biomass at the end of experiment than at the initial inoculations. The module kept at a 10 cm depth presented the greatest average biomass (186,3), followed by that kept at 20 cm (180,4 g) and the surface module (169,9 g). Biomass variations showed algae to suffer the direct effects of depths. Biomass loss was associated with the factors that influence light penetration, such as sediment deposits above the thallus, rate of evaporation and precipitation. The smallest loses occurred in the algae kept on surface (0,16%), followed by the algae kept at 20 cm (0,20%) and 10 cm (0,22%). The specific growth rate (SGR) of G. birdiae showed no significant difference between the three depths nor the sample periods. Nevertheless, the modules kept at 10 and 20 cm depths presented similar growth evolution, both growing 0,38%?per day-1, while the module kept on surface had an average SGR of 0,36%?day-1. The models related to growth rate demonstrated temperature, salinity, pH, orthophosphate, ammonium, precipitation and turbidity as the principal environmental parameters influencing the development of G. birdiae / Este estudo avalia a influ?ncia da profundidade e dos par?metros ambientais sobre o desenvolvimento de Gracilaria birdiae Plastino & Oliveira (Gracilariaceae Rhodophyta) em condi??es eutr?ficas de um viveiro org?nico de camar?o Litopenaeus vannamei. Estruturas de PVC (m?dulos), contendo quatro cordas com 150 g de macroalgas, foram mantidas por 35 dias em tr?s profundidades distintas (superf?cie, 10 e 20 cm de profundidade). Semanalmente foram realizadas as pesagens de biomassa ?mida e o monitoramento dos par?metros ambientais (temperatura, salinidade, turbidez, pH, transpar?ncia, precipita??o pluviom?trica, taxa de evapora??o, insola??o, radia??o solar acumulada, nitrito, nitrato, ?on am?nio e ortofosfato). Nas tr?s profundidades propostas, as macroalgas apresentaram, no fim do experimento, biomassa superior ao in?culo inicial. O m?dulo mantido a 10 cm de profundidade apresentou a maior m?dia de biomassa (186,3 g), seguido pelo m?dulo mantido a 20 cm (180,4 g) e o m?dulo mantido na superf?cie (169,9 g). As varia??es de biomassa apontaram que as algas sofrem efeitos diretos da profundidade. As perdas de biomassa estiveram associadas aos fatores que influenciam na penetra??o de luz como a deposi??o de sedimento sobre os talos, taxa de evapora??o e taxa de precipita??o. As menores perdas ocorreram nas algas mantidas na superf?cie (0,16%), seguidas pelas algas mantidas a 20 cm (0,20%) e a 10 cm (0,22%). As taxas de crescimento espec?fico (TCE) de G.birdiae n?o apresentaram diferen?as significativas entre as tr?s profundidades e nem entre os per?odos amostrais. Entretanto, os m?dulos mantidos a 10 e 20 cm mostraram evolu??es de crescimento bastante semelhantes, ambos cresceram 0,38%?dia-1, enquanto o m?dulo mantido na superf?cie obteve a TCE m?dia de 0,36%?dia-1. Os modelos relacionados ?s taxas de crescimento apontaram a temperatura, salinidade, pH, ortofosfato, ?on am?nio, precipita??o e turbidez como os principais fatores ambientais a influenciar no desenvolvimento de G. birdiae