As ectothermic marine megafauna, sea turtle physiology and ecology are tightly intertwined with temperature, seasonality, and oceanography. Identifying how turtles respond when exposed to cold water, how they adapt to cold environments when they need to explore cold environments in order to forage, and what foraging resources are exploited by sea turtles are all components central to their conservation. Cold-stunning is a well-documented phenomenon that occurs when water induced decreases in sea turtle body temperature cause turtles to become immobilized and wash ashore. While most cold-stunned turtles are rescued and rehabilitated, we do not know whether cold-stunning is an acute transient occurrence, or a symptom of a bigger environmental problem. Further, while in some environments avoiding cold water is preferential, in other habitats, sea turtles need to inhabit cold environments in order to forage. Along the Eastern Pacific Rim, discrete upwelling locations are characterized by high primary productivity and unusually cold water. In these environments, avoidance is not possible and sea turtles require physiological adaptions to mitigate body temperature decreases in cold water. Little is known about how turtles handle upwelling environments, despite the fact that sea turtles remain in these habitats regardless of water temperature fluctuations. Because upwelling habitats provide increased nutrient presence, and sea turtles are opportunistic foragers, quantification of diet composition will further our understanding of why sea turtles remain in cold water environments year-round. Diet composition in multiple populations of cohabitating sea turtles revealed partitioning that results in reduced inter-specific competition. Further, flexibility in diets provides a wide range of ecosystem services central to habitat resiliency. Therefore, conservation of endangered sea turtles requires complete ecosystem conservation, and complete understanding of the interconnectivity of sea turtles and their environments is crucial.<br>

The prevalence of hypoxia in aquatic systems has increased in recent decades and climate change is expected to worsen the extent and severity of hypoxic phenomena worldwide. Moreover, aquatic hypoxia has produced adverse ecological consequences and stimulated research interest within the Laurentian Great Lakes. The physiological stress imposed by hypoxia reduces habitat quality for most aquatic biota and causes changes in patterns of resource use and food web dynamics. We conducted a review of the primary literature to identify trends in prevalence of Great Lakes hypoxia research and broadly classify the unique hypoxic conditions afflicting Great Lakes ecosystems. We found that the majority of research effort toward Great Lakes hypoxia is focused on the Lake Erie central basin. Our review further revealed that this does not characterize the breadth of hypoxic phenomena that occur throughout the Great Lakes region. We then utilized a long-term monitoring dataset provided by the U.S. Environmental Protection Agency Great Lakes National Program Office to quantify the impact of Lake Erie central basin hypoxia on habitat quality of several fish species. We found that bioenergetics-based growth-rate potential models have a potential application as the framework for the development of biological endpoints that measure the effects of hypoxia on aquatic biota. Finally, we utilized stable isotope analysis to look for broad spatial and temporal trends in resource utilization within distinct regions of the Lake Erie central basin, with hypoxia and large-scale hydrodynamic patterns serving as potential driving patterns for spatial differences.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Brazil has a vast area consisting of forage plants, therefore, a large number is at some stage of degradation mainly due to inappropriate choice of the species in relation to the cultivation environment, and as a result, this work took place in order to evaluate the Morphogenesis of White-Band Grass Submitted to Nitrogen Fertilization. The experiment was conducted to evaluate the morphogenetic, structural and productive characteristics of White-Band grass (Digitaria umfolozii) subjected to nitrogen fertilization from January to May 2014. Five doses of nitrogen were evaluated: 0, 100, 200, 300 and 500 kg/ha. The experimental outline was randomized blocks, with four repetitions. Nitrogen fertilization did not affect (P> 0.05) the final length of the leaves, leaf senescence rate, the number of green leaves per tiller, plant height and the ratio of leaf to stem of grass-Range White, presenting, respectively average amounts of 26.9 cm; 0.77 cm / tiller day; 4.2 leaves / tiller; 43.4 cm and 1.04. The appearance and leaf elongation rates, the tiller population density and accumulation of forage, leaves, stems and dead materials of White-Band grass were influenced by nitrogen doses adjusted to a positive quadratic equation (P <0.05) by nitrogen doses. In general, the increase in the amount of nitrogen applied increased the amounts of these rates, reaching maximum points at doses between 300 and 400 kg/ha according to the respective adjusted models. Phyllochron and the lifespan of the leaves were affected in a negative quadratic way (P <0.05) by nitrogen doses. Similarly, the increase in the amount of nitrogen applied declined the values of these rates, reaching minimum points at doses between 300 and 400 kg /ha, according to the respective equations set. The stem elongation rate increased linearly with the nitrogen dose. The White-Band grass has a higher renewal of tissues and productivity when fertilized. The improvement in productive characteristics of White-Band grass reaches maximum amount with nitrogen doses around 300 kg/ha. / O Brasil possui uma vasta área composta por plantas forrageiras, no entanto, grande parte encontra-se em algum estagio de degradação devido principalmente a escolha inadequada da espécie em relação ao ambiente de cultivo, diante disso realizouse esse trabalho a fim de avaliar a Morfogênese do Capim Faixa-Branca Submetido a Adubação Nitrogenada. O experimento foi desenvolvido objetivando avaliar as características morfogênicas, estruturais e produtivas do capim Faixa-Branca (Digitaria umfolozii) submetido a adubação nitrogenada, no período de janeiro a maio de 2014. Foram avaliadas cinco doses de nitrogênio: 0, 100, 200, 300 e 500 kg/ha. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições. A adubação nitrogenada não influenciou (P>0,05) o comprimento final das folhas, a taxa de senescência foliar, o número de folhas vivas por perfilho, a altura das plantas e a relação folha:colmo do capim Faixa-Branca, apresentando, respectivamente, valores médios de 26,9 cm; 0,77 cm/perfilho dia; 4,2 folhas/perfilho; 43,4 cm e 1,04. As taxas de aparecimento e de alongamento de folhas, a densidade populacional de perfilhos e os acúmulos de forragem, de folhas, de colmos e de material morto do capim Faixa-Branca foram influenciadas pelas doses de nitrogênio ajustando-se a uma equação quadrática positiva (P<0,05) pelas doses de nitrogênio. De maneira geral, a elevação na quantidade de nitrogênio aplicada aumentou os valores destas taxas, atingindo pontos de máximo com doses entre 300 e 400 kg/ha, segundo os respectivos modelos ajustados. O filocrono e a duração de vida das folhas foram afetados de maneira quadrática negativa (P<0,05) pelas doses de nitrogênio. De maneira semelhante, a elevação na quantidade de nitrogênio aplicada diminuiu os valores destas taxas, atingindo pontos de mínimo com doses entre 300 e 400 kg/ha, segundo as respectivas equações ajustadas. A taxa de alongamento de colmo aumentou linearmente com a dose de nitrogênio. O capim Faixa- Branca apresenta maior renovação de tecidos e produtividade quando adubado. A melhoria nas características produtivas do capim Faixa-Branca atingem valores máximos com doses de nitrogênio em torno de 300 kg/ha.

Orientador: Jose Teixeira Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-15T15:44:54Z (GMT). No. of bitstreams: 1 Tonello_KellyCristina_D.pdf: 3209931 bytes, checksum: ad807b85c48d80b43bb9c5e89fb27160 (MD5) Previous issue date: 2010 / Resumo: O crescimento e o desenvolvimento dos vegetais é conseqüência de vários processos fisiológicos controlados pelas condições ambientais e características genéticas de cada espécie vegetal. Este estudo teve por objetivo caracterizar o comportamento ecofisiológico da transpiração (E) e condutância estomática (Gs) de dois clones de Eucalyptus grandis x Eucalyptus urophylla (C041 e P4295) sob diferentes condições de disponibilidade hídrica no solo e em função de variáveis ambientais como radiação global (Rg), radiação fotossinteticamente ativa (Qleaf) e déficit de pressão de vapor da atmosfera (DPV). As aferições foram realizadas ao longo do período de fevereiro de 2007 a agosto de 2008 em três escalas de estudo designadas como vaso, parcela e bacia hidrográfica. Medidas de potencial hídrico antemanhã (?pd) foram realizadas para o acompanhamento das disponibilidades hídricas no solo. Após o conhecimento do comportamento ecofisiológico dos clones em função das variáveis ambientais e ?pd, buscou-se relacionar as respostas obtidas na escala vaso com as escalas parcela e bacia hidrográfica por meio de modelos ecofisiológicos desenvolvidos para a mudança de escala ao nível de folha. De acordo com os resultados, as variáveis ecofisiológicas estiveram diretamente associadas às variáveis ambientais e ao ?pd tanto para o clone C041 quanto para o clone P4295. Foram observados entre os clones comportamentos ecofisiológicos distintos quando associados à Qleaf, DPV e ?pd. Os clones apresentaram-se diferentes na amplitude de resposta de E e Gs em função de Qleaf e DPV entre as escalas, porém, observou-se a mesma tendência de comportamento, com exceção da relação Gs x DPV para o clone C041, entre escala vaso e parcela/bacia hidrográfica. Os modelos propostos para a mudança de escala de folha para folha mostraram-se satisfatórios, principalmente nas relações envolvendo a radiação fotossinteticamente ativa. Contudo, não apresentaram bons resultados para a extrapolação das respostas ecofisiológicas de Gs em função do DPV / Abstract: The growth and development of plants is a consequence of several physiological processes controlled by environmental conditions and genetic characteristics of each plant species. This study aimed to characterize the ecophysiological behavior of transpiration (E) and stomatal conductance (Gs) of two clones of Eucalyptus grandis x urophylla (C041 and P4295) under different soil water conditions and according to environmental variables such as global radiation (Rg), photosynthetic active radiation (Qleaf) and a vapor pressure deficit of the atmosphere (VPD). The measurements were performed during the period February 2007 to August 2008 on three scales of study designated as a pot, plot and watershed. Predawn leaf water potential (?pd) measurements were performed to monitor water availability in the soil. After the knowledge of the ecophysiological behavior of the clones on the basis of environmental variables and ?pd, sought to link the responses obtained in the pots scale with pot and watershed through ecophysiological models developed for scaling up leaf from leaf. According to the results, the ecophysiological behavior were directly associated with environmental variables and the ?pd both to the C041 as for P4295. Were observed among different clones ecophysiological behavior when associated with Qleaf, VPD and ?pd. The clones were different in amplitude of E and Gs as function of Qleaf and VPD between the scales, however, showed the same pattern of behavior, except for Gs x VPD for clone C041 between pot and plot / watershed scale. The proposed models for the scaling up from leaf to leaf were satisfactory, especially in relationships involving the Qleaf. However, they not provided good results for the extrapolation of ecophysiological responses of Gs as a function of VPD / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola