Understanding the movement and feeding habits of marine animals is crucial when managing their populations. The molecular, and stable carbon isotope composition of fatty acids from an organism provides time-integrated information on its dietary intake. Hence, when spatial differences in the quality of seston exist it should be able to trace these differences up into higher trophic level organisms. The presented study evaluates the applicability of 13C/12C ratios of individual fatty acids, as natural tags and dietary markers in marine pelagic organisms. In addition, the use of 13C/12C ratios of bulk sample, as well as fatty acid composition data in examining the movement, and diet of animals are further explored. Samples of particulate organic matter, zooplankton, larval fish and juvenile salmon collected during three cruises off the west coast of Vancouver Island were analyzed. The fatty acid composition, stable carbon isotope ratio of either bulk sample, or individual fatty acids could typically distinguish samples collected in continental shelf waters from off-shelf samples. The differences in fatty acid composition between the adjoining food webs seem to be mainly caused by the different contribution of diatom-derived material to the base of the food web. The higher 13C/12C ratios found in the diatom-richer seston in shelf waters were not simply caused by the higher contribution of diatoms. Instead, stable carbon isotope data on individual fatty acids indicate that growth conditions favouring diatom growth caused 13C-enrichment in algae other than diatoms as well. The relative abundance of polyunsaturated fatty acids, such as docosahexaenoic acid (22:6n-3), were found to increase with trophic level. Whereas the abundance of saturated, and monounsaturated fatty acids was higher in organisms from lower trophic levels. This suggests that the fatty acid composition may be a useful trophic level indicator. However, literature data indicate that these trends observed in seston. zooplankton, larval fish and juvenile salmon, do not hold for larger organisms and adult life stages. / Graduate

New pedologic, carbon isotope and phytolith analyses along with stratigraphic correlations to nearby archaeological sites record the spatial and temporal distribution of past vegetation patterns in the Sac Valley Archaeological District of southwest Missouri. Radiocarbon ages obtained from a soil core along Bear Creek, CB5, are related to those from Hajic et al. (1998, 2000) indicating that the CB5 location contains correlative middle Rodgers Shelter submember deposits. This relationship also indicates that sedimentation was approximately two times greater at the CB5 locality than at the Big Eddy (23CE426) archaeological site providing much higher temporal resolution for the alluvial history as well as the vegetation proxies during the early to middle Holocene. Most midcontinent climate proxy records include indications of an early Holocene warm period when prairie replaced forests, then a cooler period in which trees dominated the landscape, followed by a warmer middle Holocene period when prairie vegetation was dominant. However, the CB5 δ13C profile of mixed C3/C4 vegetation indicates either that the vegetation at this location was not as sensitive to climate change or that this location was buffered from other influences, e.g. fires, which were critical to the expansion of prairie vegetation. On the other hand, the phytolith assemblages at CB5 indicate that there were periods with abundant C4 grasses even though the δ13C values indicate a dominance of C3 vegetation. This indicates that in the mixed forest/prairie ecotone interpretations of past vegetation from either carbon isotopes or phytolith assemblages alone may not accurately reflect patterns of vegetation. A new core, DDY-KR2, was obtained from the Big Eddy (23CE426) archaeological site and a finer resolution of δ13C values at Big Eddy increased the detail about alluvial activity and revealed subtle changes in the vegetation. The vegetation types suggested by the δ13C values for DDY-KR2 are reflected in the phytolith assemblages validating their usefulness in reconstructing local vegetation history.

Ph.D. / Organic Chemistry / The use of electron impact mass spectrometry for isotopic analysis is an established technique; however, its application to problems involving biologically produced molecules enriched in 13C has been severely limited. This limitation is shown to arise because of data reduction techniques which are, for practical purposes, incapable of dealing with the complex situation of multiple enrichment sites, limited isotope abundance, and complex spectral regions. Two approaches for detailed isotopic analysis of EIMS intensity are presented and illustrated using model data, literature data, and original data from biosynthetically enriched compounds. The first approach which allows for sequential variation of any one parameter is shown to be of value in experimental design through construction of ion cluster contour diagrams which summarize the variation of isotopic distribution, molecular size, and uncertainty in measurement with total isotopic content. The second approach differs in concept from previous methods and is especially promising for application to problems involving multiple sites of enrichment, limited isotopic abundance, and complex spectral regions. The key concept of this approach is that the roots of the polynomials constructed from observed spectral intensities are analytically related to the isotopic content and the isotopic distribution of the ions giving rise to the intensities.

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The northern Churchill Province is an intensely explored, yet poorly researched target area for diamonds. I examined the mantle sources and residence history of diamonds from Aviat, located on the Melville Peninsula. Aviat diamonds display a δ13C range extending far below the average mantle value of -5‰ indicating eclogitic sources must be present. Crustal protoliths, carrying the organic matter implied by strongly 13C depleted diamond compositions, likely were supplied via subduction. The main population of diamonds around -5‰ may be either eclogitic or peridotitic. The CL patterns and variation of δ13C values within diamonds indicate that at least two diamond growth events, interrupted by periods of resorption, occurred at Aviat. Nitrogen and δ13C are decoupled indicating that multiple fluid sources contributed to diamond formation at Aviat. Mantle residence temperatures for most Aviat diamonds range from ~1050-1150⁰C, indicating a range of source depths.

xvi, 257 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1975)--The Dept. of Agricultural Biochemistry and Soil Science, University of Adelaide

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An experimental study of the low lying excited states of C¹¹ has been made using the B¹⁰(d ,nɣ )C¹¹ reaction at a deuteron bombarding energy of 0.8 Mev. Measurements were made of the n- ɣangular correlations of the ground state gamma transitions from the 6.49 and 4.32 Mev levels, and of the gamma ray branching ratios of the 6.49, 4.81 and 4.32 Mev levels. The apparatus used for the measurements was a combination of a NaI(T1) gamma ray spectrometer and an improved fast neutron time-of-flight spectrometer, developed by the author. Theoretical analysis of the n-ɣ angular correlations showed that the 6.49 Mev and 4.32 Mev levels are formed by the capture of p½ protons This restricts the Jπ values of these levels to (5/2)¯ or (7/2)¯. The parities of the states observed in this experiment are all known to be negative from the high energy stripping data of Cerineo and Maslin et al. A comparison of the experimental branching ratios with the theoretical branching ratios predicted by the intermediate coupling shell model is consistent with the following spin and parity assignments in C¹¹ : g.s. (3/2)¯, 2.00 Mev (1/2)¯, 4.32 Mev (5/2)¯, 4.81 Mev (3/2*)¯ and 6.49 Mev (7/2)¯. These assignments are in agreement with other recent results. The correspondence of these levels in C¹¹ with those of B¹¹ is consistent with the hypothesis of the charge independence of nuclear forces. The experimental results agree in some cases and disagree in others with the intermediate coupling shell model calculations of Kurath. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

We report here a sample of 5 cheek teeth of a primitive hipparion from the early late Miocene Ethiopian locality of Chorora. This sample represents the oldest hipparion known from Ethiopia, and probably East and South Africa. The sample exhibits a number of distinctly primitive characters that suggest its provisional referral to "Cormohipparion" sp. The Chorora hipparion has none of the more advanced features typical of the latest Miocene-Pleistocene African hipparionine lineage Eurygnathohippus, maintaining a low crown height, lack of ectostylids and pli caballinids. The Chorora hipparion does exhibit a mesowear signal, suggesting that it was a mixed-feeder. The carbon isotope signal also suggests that it was a mixed-feeder that included both browse and C4 grass in its diet.