Anthropogenic activities are fundamentally altering the chemistry of the world’s oceans. Many of these modifications could have a significant impact on the health of marine organisms. Yet, despite being proposed as one of the most significant threats that marine ecosystems face, to date very little is known about the impact of anthropogenic climate change, and ocean acidification in particular, on host defence. The aims of this thesis are to investigate the impact of environmental stressors on the invertebrate immune response, providing empirical data on how anthropogenically induced stressors will impact the invertebrate immune system and how this will impact organism condition and subsequent physiological trade-offs. Exposure to reduced seawater pH and increased temperature significantly reduced the immune response in the blue mussel, Mytilus edulis. This reduction in immune response could indicate stress-induced immune dysfunction. However, the immune system protects an organism from infectious disease, ensuring survival, and should therefore be evaluated functionally rather than immunologically. By subsequently exposing mussels to a bacterial challenge this study demonstrated that an earlier study which measured a reduction in host defence represented a trade-off of immune system maintenance costs, with mussels maintaining a capacity to up-regulate immune defence when required. However, whilst this immune plasticity ensures mussels are able to survive a pathogen exposure, such a strategy appears to be physiologically costly. This cost is seen as a reduction in reproductive investment, an altered energy metabolism and an altered fatty acid composition in organisms exposed to low pH. Therefore the overarching picture that emerges is, without measuring physiological processes functionally, and in neglecting any physiological trade-offs, it is possible that many studies may misinterpret the complex physiological responses of marine organisms to ocean acidification.

This research essay examines the emergence and development of the Joint Standing Committee on Foreign Affairs, Defence and Trade and its attempts to influence foreign policy. Established as the Joint Committee on Foreign Affairs in 1952, it was the first committee to have a specific portfolio alignment. The purpose of the committee was to ensure that a considerable number of parliamentarians could become informed about foreign affairs issues. The establishment of a committee for such a purpose was surprising in that proponents of parliamentary reform at that tune were strongly advocating that a comprehensive system of committees be created for the purposes of financial scrutiny of government expenditure and consideration of legislation. Against this background it is interesting that the new committee was not given - and indeed showed no intention of assuming - the role of scrutinising the activities of the Department of External (and later, Foreign) Affairs. It is also interesting that Prime Minister Robert Menzies instigated the committee despite the fact that the government - and particularly the Minister for External Affairs R G Casey - feared the committee might go beyond its terms of reference and attempt to exert influence on government policy. Consequently the government imposed severe restrictions on the committee's activities which resulted in the Opposition steadfastly refusing to participate in the work of the committee for 15 years. Once some of these restrictions were removed, the committee began to operate as a bipartisan committee in 1967 and promptly set about attempting to influence government policy in foreign affairs. Casey's worst fears were realised. Over the years the brief of the committee expanded into the areas of defence and trade. Eleven of the committee's reports address significant defence issues and since 1987 the committee has conducted extensive inquiries into trade matters. For the purposes of this research essay however I have focused on the development of the committee's interest and influence in the area of foreign affairs. Chapter One of this essay describes the background of parliamentary reform which resulted in the establishment of a comprehensive system of committees within the Australian Parliament. Against this background the emergence of the Joint Committee on Foreign Affairs is outlined in Chapter Two. Chapter Three identifies the major trends in the work of the committee while Chapter Four examines the influence and some of the mechanisms through which the committee has exerted pressure on foreign affairs policy. The conclusions of my research are addressed in Chapter Five. This research essay is based on an analysis of official committee documents which address foreign affairs issues from 1967 to the present. The major sources for the essay therefore are the reports of the committee, government responses to those reports and parliamentary debates. Other works consulted include academic journals and monographs. I have also gained numerous insights into the powers and limitations of committees through informal discussions with members of various committees and colleagues. To these people I am indebted for their thoughtful and provocative remarks. In particular I thank Professor John Halligan of the University of Canberra for his assistance and encouragement in bringing this research essay to its conclusion.