In the Classroom
How do fish in the Southern Ocean keep from freezing?

Participants

Steven Young

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Photo of Steven YoungData collected on this cruise will form part of my PhD project investigating the mechanisms of cold-induced angiogenesis (growth of new capillaries) in fish. Data collected from cold adapted Antarctic fish will complement that being obtained in cold acclimated temperate fish. Whilst on board the ship I shall perform myography experiments to investigate the reactivity (contraction and dilatation) of the vessels in the branchial circulation of a number of sub-Antarctic species. These data will be compared with those obtained from high Antarctic species to investigate possible latitudinal variations. Additionally for analysis back in England I shall obtain vascular corrosion casts of the locomotory muscle of fish that can be used to generate data on the three-dimensional topology of the vascular network. Immunohistochemistry samples will be taken for quantification of the capillary supply and fibre dimensions, and transmission electron microscopy samples for studies in differences infine structure, e.g. the morphology of individual capillaries. Finally, samples will be taken for molecular biology studies into the possible genes/ proteins responsible for such differences in the vascular reactivity that may be observed, e.g. adrenoceptor distribution.

This study aims to shed light on possible patterns in the tissue oxygen supply in fish, more specifically to answer such questions as: are there differences in short-term acclimation and evolutionary adaptation to the cold? Is cold adaptation really the significant factor in determining vascular supply or are other factors such as phylogenetic lineage or activity levels more important?