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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of temperature change on the New Zealand marine fish, Notolabrus celidotus

Hooper, Julia Kate January 2008 (has links)
Physiological responses of the labrid fish Notolabrus celidotus to temperature change, found thermal compensation to be more advanced in cold environmental temperatures compared to warm environmental temperatures. N. celidotus was acclimated for 28 days to 8, 14 and 24ºC and metabolism, ventilatory and circulatory function, condition factor, swimming ability, thermal tolerance and hypoxia tolerance investigated. N. celidotus acclimated to 8ºC almost achieved full thermal compensation, which resulted in, resting and maximum oxygen consumption not being significantly different to 14ºC acclimated fish. In contrast, N. celidotus acclimated to 24ºC achieved only partial or no metabolic thermal compensation. This resulted in high resting oxygen consumption and a reduced aerobic scope for activity, which had detrimental affects on other physiological parameters investigated. Thermal compensation was achieved for the resting ventilation rate of the 8ºC acclimated fish, which is most likely needed in order to meet the high oxygen demands incurred by metabolic thermal compensation. No thermal compensation was achieved for any other ventilation rate or for heart rate, at any acclimation temperature. Thermal compensation at the level of heart and ventilation rate of the 24ºC acclimated fish, would have been limited by the lack of metabolic thermal compensation. A low condition factor of the 24ºC acclimated fish would also have occurred due to the lack of metabolic thermal compensation, which would have caused high-energy demands and the utilization of energy stores. Thermal tolerance ranges shifted in the direction of temperature change for all acclimation groups, which indicates thermal compensation must have occurred to some degree at a variety of organizational levels. Swimming ability reflected metabolic thermal compensation, with the swimming ability of the 8ºC acclimated fish being similar to the 14ºC acclimated fish. In comparison, the 24ºC acclimated fish had a diminished swimming ability, which is likely to have occurred due to the reduced aerobic scope for activity of these fish and the low condition factor. The findings suggest that the increasing temperatures associated with climate change will cause N. celidotus to migrate to cooler waters in order to survive. This response will have a large effect on New Zealand’s marine ecosystem as N. celidotus is abundant in New Zealand waters and is an important part of the food chain. Additionally, the response of N. celidotus may be an indicator of the response of other New Zealand species to climate change, which could cause huge upset to New Zealand commercial fisheries.
2

The effect of temperature change on the New Zealand marine fish, Notolabrus celidotus

Hooper, Julia Kate January 2008 (has links)
Physiological responses of the labrid fish Notolabrus celidotus to temperature change, found thermal compensation to be more advanced in cold environmental temperatures compared to warm environmental temperatures. N. celidotus was acclimated for 28 days to 8, 14 and 24ºC and metabolism, ventilatory and circulatory function, condition factor, swimming ability, thermal tolerance and hypoxia tolerance investigated. N. celidotus acclimated to 8ºC almost achieved full thermal compensation, which resulted in, resting and maximum oxygen consumption not being significantly different to 14ºC acclimated fish. In contrast, N. celidotus acclimated to 24ºC achieved only partial or no metabolic thermal compensation. This resulted in high resting oxygen consumption and a reduced aerobic scope for activity, which had detrimental affects on other physiological parameters investigated. Thermal compensation was achieved for the resting ventilation rate of the 8ºC acclimated fish, which is most likely needed in order to meet the high oxygen demands incurred by metabolic thermal compensation. No thermal compensation was achieved for any other ventilation rate or for heart rate, at any acclimation temperature. Thermal compensation at the level of heart and ventilation rate of the 24ºC acclimated fish, would have been limited by the lack of metabolic thermal compensation. A low condition factor of the 24ºC acclimated fish would also have occurred due to the lack of metabolic thermal compensation, which would have caused high-energy demands and the utilization of energy stores. Thermal tolerance ranges shifted in the direction of temperature change for all acclimation groups, which indicates thermal compensation must have occurred to some degree at a variety of organizational levels. Swimming ability reflected metabolic thermal compensation, with the swimming ability of the 8ºC acclimated fish being similar to the 14ºC acclimated fish. In comparison, the 24ºC acclimated fish had a diminished swimming ability, which is likely to have occurred due to the reduced aerobic scope for activity of these fish and the low condition factor. The findings suggest that the increasing temperatures associated with climate change will cause N. celidotus to migrate to cooler waters in order to survive. This response will have a large effect on New Zealand’s marine ecosystem as N. celidotus is abundant in New Zealand waters and is an important part of the food chain. Additionally, the response of N. celidotus may be an indicator of the response of other New Zealand species to climate change, which could cause huge upset to New Zealand commercial fisheries.
3

Accumulation of trace elements in aquatic food chains due to sea-fill activities.

Mohamed, Fathimath January 2015 (has links)
Elevated levels of trace elements in the environment are of great concern because of their persistence, and their high potential to harm living organisms. The exposure of aquatic biota to trace elements can lead to bioaccumulation, and toxicity can result. Furthermore, the transfer of these elements through food chains can result in exposure to human consumers. Sea-fill or coastal fill sites are among the major anthropogenic sources of trace elements to the surrounding marine environment. For example, in the Maldives, Thilafushi Island is a sea-fill site consisting of assorted municipal solid waste, with multiple potential sources of trace elements. However, there is limited data on environmental trace element levels in the Maldives, and although seafood is harvested from close to this site, there is no existing data regarding trace element levels in Maldivian diets. Following the Christchurch earthquakes of 2011,

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