The purpose of this study was to determine the general patterns of response by tree species common to Everglades Tree Islands (TI) when conditions limiting optimal growth are improved by fertilization on LILA tree islands. Experiments were conducted on constructed TI in the Loxahatchee Impoundment Landscape Assessment (LILA). Thirty-six trees of two species, Annona glabra and Chrysobalanus icaco, were randomly selected on each of four tree islands. Two tree islands have peat overlying limestone cores and two are composed solely of peat. Each tree was treated with one of three nutrient regimes: +N, +P, or Control (no addition of nutrients). A highly significant P-treatment effect on growth rate, leaf TP and leaf N:P ratio were observed in both species in comparison to Control trees. In contrast, neither of the species responded to N-fertilization. The mass N:P ratios and δ13C in P-treated trees exhibited a positive correlation with Relative Elevation (RE) for both species. These findings suggested that the tree growth at LILA tree islands was P-limited on both substrates (limestone and peat).

L’évolution spatio-temporelle des populations d’Ophiocomina nigra et d’Ophiothrix fragilis (Ophiuridés, Echinodermes) a été étudiée dans deux écosystèmes contrastés de la pointe de Bretagne (France); la rade de Brest et la baie de Douarnenez. Entre la fin des années 80 et 2011, la population d’O. nigra s’est très largement étendue sur l’ensemble des zones d’études et a vu sa densité augmenter d’un facteur 5 en rade de Brest. Dans ce site, l’expansion d’O. nigra a généré de profonds changements qui se sont progressivement traduits entre autre par une exclusion spatiale d’O. fragilis du bassin central vers la partie sud de la zone d’étude où l’espèce colonise des coquilles vides de crépidules; Crepidula fornicata. L’expansion d’O. nigra a été mise en relation avec la combinaison de possible changements globaux du milieu et les traits biologiques de l’espèce. Les isotopes stables naturels (δ13C & δ15N) et les marqueurs d’acides gras ont été utilisés pour décrire l’écologie trophique des deux ophiures par un suivi in situ, sur des stations sélectionnées en raison de leurs situations contrastées (influence continentale vs influence océanique). Les facteurs de discrimination (∆δ13C et ∆δ15N) ont été calculés en expérimentation pour les deux espèces avec trois types de sources et ont montré principalement un effet de la qualité de la nourriture et de l’état reproducteur des espèces sur ces facteurs et des différences interspécifiques. Le suivi in situ a principalement révélé des différences interspécifiques dans l’alimentation des espèces. Le phytoplancton (diatomées) apparait en été comme une source majeure pour les deux espèces et plus importante pour O. fragilis. Des valeurs en δ15N plus élevées chez O. nigra par rapport à O. fragilis associées à une plus forte contribution de bactéries, de détritus et de matériel d’origine animal, indiquent que l’espèce exploite une grande diversité de sources de nourriture expliquant en partie son succès. Les macroalgues (Ulva sp) et les apports terrigènes semblent jouer un rôle trophique mineur pour les deux espèces, malgré une augmentation significative dans les sites plus confinés en fin d’étude. / The temporal and spatial changes in the densities and biomass of two co-occurring ophiuroid populations Ophiocomina nigra and Ophiothrix fragilis (Ophiuroidea, Echinodermata) were studied in two contrasted coastal systems at the tip of Brittany (France); the Bay of Brest and the Bay of Douarnenez. Ophiocomina nigra increased about 5 times in density in the Bay of Brest. The current distribution pattern in this site revealed a spatial exclusion of O. fragilis from the central part toward the southern part of the study area and now overlapped dead slimper-limpet Crepidula fornicata beds. The success of O. nigra colonization is linked to its biological and functional traits, as well as deep changes in food supply over the studied period. Stable isotopes (δ13C and δ15N) and fatty acids were used as complementary tools to characterize the trophic ecology of these 2 ophiuroids. Preliminary, the tissue-diet discrimination factors (Δδ13C and Δδ15N) were studied and revealed differences between species but appeared to be mainly driven by the diet and to a lesser extent the physiological state of the organisms. We designed a field survey and used the dual stable isotope and fatty acid biomarkers approach to explore the contribution of oceanic vs continental inputs to the diet of ophiurids, according to seasons. In our study, spatiotemporal variations in stable isotopes and fatty acid profiles of ophiurids were generally low compared to interspecific differences. Both ophiurids rely mainly on phytoplankton (diatoms) inputs with higher contribution for O. fragilis. The more δ15N-enriched values as well as higher contribution of bacteria, detritus and animal material inputs to the diet of O.nigra supported a broad range of food sources to the diet of O. nigra. The terrestrial and/or green algae did not contribute greatly to the diet of ophiurids despite a significant increase of these food sources at the end of the study period in both inside sites.

This thesis deals with a medieval material from Rounala in Karesuando parish, Norrbotten county, Lapland. The aim is to reconstruct the diet and mobility patterns. It is through carbon, nitrogen and sulphur stable isotopes and radiocarbon that both pastoralist traits and whether which part Christianity played in the burial traditions of these human remains is being studied. Another aim is to discuss the repatriation issue as these remains are subjected to. The results mainly show that all individuals had a mixed diet and no pastoral way of living has been established. Furthermore, individual 3 is suffering from pathological changes. With radiocarbon dates ranging from 1300 to 1720 AD, two groups can be distinguished as to whom had been buried before and after the construction of the church. And repatriation is being discussed as an issue to who have ownership over ancient remains.

The combined methods of stomach content analysis and stable 15N and 13C isotope biochemistry analysis were used to investigate the trophic dynamics and feeding ecology of coastal pelagic fishes in the waters off southeastern Florida, USA. The coastal pelagic fish complex includes blackfin tuna Thunnus atlanticus, dolphinfish Coryphaena hippurus, king mackerel Scomberomorus cavalla, little tunny Euthynnus alletteratus, skipjack tuna Katsuwonus pelamis, and wahoo Acanthocybium solandri. These coastal teleosts, particularly the tunas and wahoo, are primarily targeted by recreational anglers. However, there is a shortage of available trophic and diet composition data concerning these fishes of the coastal pelagic ecosystem. Stomach and muscle tissue samples were collected from the species of various lengths over a three-year period from March 2010 and March 2013. Across all six species, teleost fishes dominated the prey with an average 64.5% by occurrence, 63.7% by number, and 89.9% by weight. There were two dominant prey families: Clupeidae and Carangidae. Dolphinfish showed the lowest diet overlap among the six species, due to the highly diverse diet. The highest diet overlap occurred between king mackerel and little tunny. The mean δ15N ranged from 8.21 ‰ (wahoo) to 13.18 ‰ (king mackerel), and the mean δ13C ranged from -18.41 ‰ (king mackerel) to -16.70 ‰ (dolphinfish). Blackfin tuna exhibited the largest δ15N range (7.22 to 13.21 ‰), as well as the largest δ13C range (-19.13 to -12.99 ‰). The δ15N and δ13C signatures in the muscle tissue showed evidence of shifts to higher trophic levels with an increase in fish size and the formation of distinct trophic groups among the coastal pelagic predators. The δ13C also suggested an inshore-offshore spatial relationship among the coastal pelagic fish. The trophic dynamics and feeding ecology data generated by this study will provide valuable baseline data for the coastal pelagic complex and future ecosystem studies.

Environmental fluctuations in the eastern Pacific Ocean are reflected in the tissues of some of its most vulnerable apex predators, the Peruvian fur seal (PFS) Arctocephalus australis ssp.and the South American sea lion (SASL) Otaria byronia.These large pinnipeds live in sympatry along the Pacific coastline of South America and forage within the neritic waters over the continental shelf. The coastal waters off Peru are a region of great environmental fluctuations due to periodic, oscillating El Niño- La Niña- Southern Oscillation (ENSO) events, which result in ecosystem-wide food web changes. Pinniped vibrissae (whiskers) are continuously growing keratinous tissues and reflect the incorporation of prey from the region. Fine resolution sampling along their length provided trophic information on a weekly to monthly time scale over several years. Vibrissae were obtained from 2010-2016 from female (n=47), male (n=17) and newborn pup (n=6) fur seals and male (n=6) sea lions collected during pinniped rookery health assessments. Stable isotope ratios (δ13C and δ15N) in vibrissae infer temporal primary production and dietary variations in individuals. ENSO conditions were dictated by the sea surface temperature anomaly (SSTA) recordings from the Niño 1+2 Index region over 12 years. Fluctuations in vibrissae δ15N were correlated to varying SSTA readings (p15N (p15N signatures (p13C revealed minor fluctuations ranging from -18.13 to -13.17‰over the 12-year period, δ13C did reveal a significant depletion and enrichment oscillation during specific points in time, such as the 2014-2016 El Niño event, which ranged from -15.09 to -13.83‰(p=0.040). Stable isotope signatures varied between genders, but not by species. Female fur seal stable isotope signatures were significantly more depleted in both δ13C and δ15N than males (p13C and δ15N were inversely correlated to each other from 2014 to 2016; this was during the strongest El Nino-Southern Oscillation event on record (p=0.002). As δ13Csignatures became more enriched, δ15N signatures depleted from 2014 until 2016. This suggests that when ENSO warm phase conditions occur, the environments resources change in historic foraging grounds, possibly forcing pinnipeds to travel farther distances offshoreto forage or altering what they feed on throughout these stressful conditions.This study serves to help understand of the impact of oceanographic influences on these pinnipeds.ENSO conditions influence the trophic dynamics and resultant survival adaptations in both of these vulnerable Peruvian marine mammals.

名古屋大学年代測定総合研究センターシンポジウム報告

North American populations of white-winged scoters (<i>Melanitta fusca deglandi</i>) have declined markedly over the past several decades. The causes for decline are uncertain, but likely involve a complexity of events occurring on wintering and breeding areas. To gain insight into potential cross-seasonal effects, I delineated Atlantic and Pacific wintering scoter populations and linked them to a shared breeding area using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) ratios in feathers. By applying this methodology to a marked breeding population at Redberry Lake, Saskatchewan, I assigned females to putative wintering areas and determined: (1) population structure; (2) the extent of winter site philopatry; and, (3) differences in vital rates and other variates in relation to winter origin. Discriminant function analysis of isotopic ratios in feather samples from known wintering locations resulted in classification probabilities of 96% (<i>n</i> = 149) for Pacific and 78% (<i>n</i> = 32) for Atlantic wintering scoters. Using this methodology, I determined that the Redberry Lake breeding population is comprised of approximately 75% Pacific and 25% Atlantic wintering birds, and its members exhibit high degrees of winter region philopatry based on the classification of successive recaptures over three field seasons. Annual variations in population structure, as well as differences in nest initiation dates and blood contaminant loads in relation to winter area suggest seasonal interactions may influence survival and reproductive success of this population. To gain insight into potential seasonal interactions, I examined nest success and female survival in relation to winter area. No significant differences in nest success in relation to winter area were found, but nests that failed before mid-incubation were not sampled. Adult female survival rate for 2000-2004 was estimated as 0.85, with no significant difference detected between wintering areas. This study demonstrated that it is important to link breeding and wintering areas to better understand the factors influencing population dynamics and to effectively address conservation issues.

North American populations of white-winged scoters (<i>Melanitta fusca deglandi</i>) have declined markedly over the past several decades. The causes for decline are uncertain, but likely involve a complexity of events occurring on wintering and breeding areas. To gain insight into potential cross-seasonal effects, I delineated Atlantic and Pacific wintering scoter populations and linked them to a shared breeding area using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) ratios in feathers. By applying this methodology to a marked breeding population at Redberry Lake, Saskatchewan, I assigned females to putative wintering areas and determined: (1) population structure; (2) the extent of winter site philopatry; and, (3) differences in vital rates and other variates in relation to winter origin. Discriminant function analysis of isotopic ratios in feather samples from known wintering locations resulted in classification probabilities of 96% (<i>n</i> = 149) for Pacific and 78% (<i>n</i> = 32) for Atlantic wintering scoters. Using this methodology, I determined that the Redberry Lake breeding population is comprised of approximately 75% Pacific and 25% Atlantic wintering birds, and its members exhibit high degrees of winter region philopatry based on the classification of successive recaptures over three field seasons. Annual variations in population structure, as well as differences in nest initiation dates and blood contaminant loads in relation to winter area suggest seasonal interactions may influence survival and reproductive success of this population. To gain insight into potential seasonal interactions, I examined nest success and female survival in relation to winter area. No significant differences in nest success in relation to winter area were found, but nests that failed before mid-incubation were not sampled. Adult female survival rate for 2000-2004 was estimated as 0.85, with no significant difference detected between wintering areas. This study demonstrated that it is important to link breeding and wintering areas to better understand the factors influencing population dynamics and to effectively address conservation issues.

Varved (annually laminated) sediments are of great interest for inference of past environmental conditions, as they provide dated records with high time resolution. After deposition, the sediment varves are affected by diagenesis; i.e., chemical, physical and biological changes that occur within the sediment. An important premise when reconstructing past environmental conditions using lake sediments is that the signal of interest is preserved in the sediment. In this thesis I have used a unique collection of ten stored freeze cores of varved lake sediment from Nylandssjön in northern Sweden, collected from 1979 to 2007. The suite of cores made it possible to follow long-term (up to 27 years) changes in iron (Fe), sulfur (S), carbon (C), nitrogen (N), δ13C and δ15N in the sediment caused by processes that occur in the lake bottom as the sediment ages. The sediment geochemistry and resulting changes were followed in years for which there are surface varves in the core series. Fe and S concentrations analyzed by X-ray fluorescence spectroscopy showed no diagenetic front in the sediment and the data do not suggest a substantial vertical transport of Fe and S in the sediment. A model based on thermodynamic, limnological, and sediment data from the lake, showed that there are pe (redox) ranges within which either FeS (reduced specie) or Fe(OH)3/FeOOH oxidized species) is the only solid phase present and there are pe ranges within which the two solid phases co-exist. This supports the hypothesis that blackish and grey-brownish Fe-layers that occur in the varves were formed at the time of deposition. C and N analyzed with an elemental analyzer showed that within the first five years after deposition the C concentration of the sediment decreased by 20% and N by 30%, and after 27 yr in the sediment, there was a 23% loss of C and 35% loss of N. The C:N ratio increased with increasing age of the sediment; from ~ 10 in the surface varves to ~12 after 27 years of aging. δ13C and δ15N analyzed on a mass spectrometer showed that δ13C increased by 0.4-1.5‰ units during the first five years, after that only minor fluctuations in δ13C were recorded. Another pattern was seen for δ15N, with a gradual decrease of 0.3-0.7‰ units over the entire 27-year-period. The diagenetic changes in the stable isotope values that occur in Nylandssjön are minor, but they are of about the same magnitude as the variation in the isotopic signal in the varves deposited between 1950-2006. My results show that diagenesis does not change the visual appearance of the varves, except for varve thickness; the varves get thinner as the sediment ages. As the color of Fe in the varves likely reflects the environmental conditions at the time of deposition this creates possibilities for deciphering high-temporal-resolution information of past hypolimnetic oxygen conditions from varves. My findings on C, N, δ13C and δ15N will have implications for interpretations of paleolimnological data. The diagenetic effects should be carefully taken into consideration when C, N, δ13C and δ15N in sediment cores are used to study organic matter sources or paleoproductivity, in particular when dealing with relatively small and recent changes. In addition to the significance of diagenetic effects on sediment parameters, a comparison of the varves in Nylandssjön and the adjacent lake Koltjärnen, and the two deep basins of Nylandssjön show that subtle features in the lakes and their catchments affect the appearance of the varves, which make interpretation of varves complicated.

No description available.