O presente trabalho apresenta um estudo de quimioestratigrafia isotópica (C, O, Sr) de detalhe, realizado numa sucessão carbonática de idade ediacariana da porção extremo norte da Faixa Paraguai, Estado do Mato Grosso. A pesquisa se justifica já que durante o Neoproterozóico a Terra sofreu profundas mudanças climáticas, as quais foram registradas em enigmáticas sucessões compostas de depósitos glaciais recobertos por rochas carbonáticas de clima quente. Estudos recentes mostram que ocorreram, pelo menos, três glaciações neste período, denominadas Sturtiana (ca. 725 Ma), Marinoana (ca. 635 Ma) e Gaskierana (580 Ma). Na tentativa de estabelecer uma correlação global entre as sucessões depositadas neste período, os geopesquisadores têm usado diversas ferramentas, principalmente a quimioestratigrafia isotópica de C, O e Sr. Na região de estudo, ocorrem diamictitos da Formação Puga recobertos por rochas carbonáticas do Grupo Araras, sobre a qual se depositam os diamictitos e carbonatos da Formação Serra Azul, definida neste trabalho. A sucessão carbonática do Grupo Araras apresentou valores de d13C variando de ? 1,7? (base) a + 4? (topo) e razões 87Sr/86Sr entre 0,7075 (na base) e 0,7084 (no topo). Estes valores são semelhantes àqueles encontrados em outras sucessões carbonáticas Marinoanas. Os calcários da Formação Serra Azul apresentaram um valores de d13C entre ? 7,5% e ? 3,2% e razões 87Sr/86Sr de ca. 0,7086, típicas das sucessões carbonáticas Gaskieranas. Os resultados isotópicos obtidos neste trabalho, associados às evidências sedimentológicas, sugerem que na história geológica de deposição da Faixa Paraguai ocorreram, pelo menos, duas importantes glaciações. / This work presents a detailed isotopic (C, O, and Sr) chemostratigraphic study carried out on the Ediacaran carbonate succession from the northernmost part of the Paraguay Belt, in Mato Grosso, Brazil. The importance of this study is related to the Earth´s profound climate changes that took place during the Neoproterozoic, which have been recorded by enigmatic sequences composed of glacial deposits immediately overlain by carbonate rocks typical of warm climate. At least three glaciations are recognized: Sturtian (ca. 725 Ma), Marinoan (ca. 635 Ma), and Gaskiers (580 Ma). In order to correlate worldwide the successions deposited in this period and to understand the complex depositional environments, isotopic tools, especially chemostratigraphy, have been widely used. In the study area diamictites of the Puga Formation are overlain by carbonates of the Araras Group, and these, in turn, are covered by diamictites and carbonates of the Serra Azul Formation, which is defined here. The Araras Group carbonates exhibited d13C values between ? 1.7? at the base and + 4 ? at the top and 87Sr/86Sr ratios ranging from 0.7075 at the base to 0.7084 at the very top. These values are similar to those of post-glacial, non-cap Marinoan carbonate successions. The limestones of the Serra Azul Formation yielded d13C values between ? 7.5 and ? 3.2 ?, and 87Sr/86Sr ratios of ca. 0.7086, typical of post-Gaskiers cap carbonates. These isotopic results, together with sedimentological evidence, suggest that two important glaciations occurred during the depositional history of the northernmost Paraguay Belt.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-20T15:19:07Z No. of bitstreams: 1 rafaelsantosdeazevedo.pdf: 2175717 bytes, checksum: 9e03ff3159a25135046d8e900cb30271 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-22T15:21:59Z (GMT) No. of bitstreams: 1 rafaelsantosdeazevedo.pdf: 2175717 bytes, checksum: 9e03ff3159a25135046d8e900cb30271 (MD5) / Made available in DSpace on 2016-07-22T15:21:59Z (GMT). No. of bitstreams: 1 rafaelsantosdeazevedo.pdf: 2175717 bytes, checksum: 9e03ff3159a25135046d8e900cb30271 (MD5) Previous issue date: 2011-09-15 / A ecologia trófica do peixe Characidium vidali Travassos 1967 (Characiformes; Crenuchidae) no rio Macaé (RJ) é descrita através de análise de conteúdo estomacal (ACE), análise de isótopos estáveis de δ13C e δ15N (AIE), ecomorfologia (EMorf) e observação subaquática (OSub). Os exemplares analisados foram coletados entre março/2004 e março/ 2005 (ACE e EMorf), e entre março/2009 e novembro/2010 (ACE e AIE) em três localidades distribuídas nos trechos alto e médio do rio Macaé (RJ). Além dos peixes, para AIE foram coletados recursos basais (perilíton, perifíton, plantas terrestres e macrófitas) e insetos aquáticos. Os itens identificados no conteúdo estomacal foram medidos, contados e quantificados por análise volumétrica. Para caracterização da dieta foi utilizado o Índice de Importância Relativa (IRI), amplitude de nicho (Simpson) e estratégia alimentar (método gráfico). Foi identificado um total de 36 itens na dieta, sendo 35 de origem autóctone. A espécie consome grande riqueza de insetos aquáticos em proporções similares, tanto espacial (ao longo do rio) quanto sazonalmente (Índice de Pianka). Chironomidae, Simuliidae e Baetidae foram os itens mais importantes de acordo com IRI. A dieta de C. vidali foi classificada como generalista, com ampla largura de nicho. Os itens mais assimilados em músculo de C. vidali e nos insetos aquáticos foram determinados por um modelo de mistura (Programa IsoSource 1.3.1). O carbono de origem autóctone é o mais importante para os insetos aquáticos e consequentemente, para C.vidali. As assinaturas de 13C no tecido dos peixes foram significativamente diferentes entre as localidades, indicando assimilação espacial diferente. O grau de palatabilidade, estimado pela razão C:N, foi maior para perifíton e Lepidoptera. Chironomidae foi o item mais abundante, porém não foi o mais assimilado em todas as localidades. A posição trófica (PT) foi calculada com base nos dados de conteúdo estomacal e resultados de δ15N, sendo que ambos os métodos indicaram C. vidali como consumidor secundário. Foram selecionadas 16 medidas morfológicas e calculados 11 índices a fim de verificar a relação entre morfologia e comportamento trófico. Os resultados dos índices são semelhantes aos encontrados para outras espécies congenéricas. A regressão linear entre tamanho de C. vidali e de dois dos itens mais abundantes na sua dieta, apontou que não há seleção de presas maiores conforme os peixes crescem de tamanho; no entanto, indivíduos menores consomem somente presas de menor porte, provavelmente por restrições morfológicas, provavelmente relacionadas a Largura relativa da boca (LRB) e Altura relativa da boca (ARB). A observação subaquática foi realizada através do método “Animal-focal”, revelando que C. vidali é uma espécie mais bentônica, que vive em ambientes de correnteza moderada a forte, substrato pedregoso, afastado das margens e utiliza a tática “Sit-and-wait predation” para se alimentar. Os quatro métodos aplicados em conjunto se mostraram satisfatórios para caracterizar a ecologia alimentar de C. vidali. / The trophic ecology of Characidium vidali Travassos 1967 (Characiformes; Crenuchidae) from Macaé River (Rio de Janeiro State, Southeastern Brazil), is described through stomach contents analysis (SCA), analysis of δ13C and δ15N stable isotopes (SIA), ecomorphology (EM) and underwater observations (UWO). Specimens were collected between March/2004 and March/2005 (SCA and EM), and between March/2009 and November/2010 (SCA and SIA) in three sites located within the upper and intermediate stretches of Macaé River. For SIA, basal resources (epilithon, periphyton, terrestrial plants and macrophytes) and aquatic insects were also sampled. Food items identified in the stomach contents were counted and had the length and volume measured. The diet was characterized using the Index of Relative Importance (IRI), niche breadth (Simpson) and feeding strategy (graphical inspection method). A total of 36 food items were identified, being 35 autochthonous. Characidium vidali consumed a high richness of aquatic insects in similar proportions, both in the spatial (along the river) and temporal (seasonal) axes (Pianka Overlap Index). Chironomidae, Simuliidae and Baetidae were the most important items according to IRI. The species was classified as a generalist, with a large niche breadth. A mixing model (IsoSource 1.3.1) was used to determine the most assimilated food items by C. vidali and aquatic insects. Autochthonous Carbon was revealed as the most important for the aquatic insects, hence for C.vidali. 13C signatures in fish muscle were significantly different among sites, indicating different assimilation along the river. Palatability, estimated by C:N ratio, was higher for periphyton and Lepidoptera. Despite Chironomidae was the most abundant item, it was not the most assimilated in all sampling sites. Trophic position (TP), calculated on the basis of SAI and δ15N results, indicated that C. vidali is a secondary consumer. Sixteen morphological measurements and 11 related indices were selected in order to determine the relation between morphology and trophic behavior. The indices values obtained are similar to those found for other congeneric species. The linear regression between fish length and lenght of the two most abundant prey showed no selection of larger prey as fish grow larger; however, smaller individuals consume only smaller-sized prey, probably due to morphological constraints, probably related to mouth opening size. For underwater observations the focal animal sampling was employed, revealing C. vidali as a rather benthic species that lives in riffles of moderate to strong flow, on rocky substrates further from the margins, and uses the “Sit-and-wait predation” foraging tactic. The four methods employed were satisfactory to characterize the feeding ecology of C. vidali.

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T00:25:50Z (GMT). No. of bitstreams: 1 GuilhermePereira_Caio_M.pdf: 4423463 bytes, checksum: b3d0cccfd6c5f84a9df0f479651580a0 (MD5) Previous issue date: 2013 / Resumo: Plantas carnívoras são aquelas que apresentam a capacidade de capturar e digerir pequenos animais, geralmente invertebrados. Os estudos com essas plantas começaram há mais de um século e, ainda hoje, não são conhecidos os mecanismos que determinaram a evolução e a distribuição geográfica dessas singularidades vegetais. Os modelos de custos--benefícios vêm, nesse sentido, atuando como guias para diversos estudos nas últimas décadas e parecem esclarecer diversos pontos obscuros quanto à ecologia e evolução dessas plantas. O gênero Philcoxia (Plantaginaceae), endêmico de campos rupestres -- ambientes associados a afloramentos rochosos e a formações de areia branca, propensos a eventuais queimadas e pobres em nutrientes --, apresenta características que acabaram por levar a questionamentos quanto à sua fisiologia. Com o acúmulo crescente de evidências, estudiosos começaram a sugerir que tais espécies pudessem apresentar mecanismos ativos de captura e digestão de presas. O estudo em questão teve como objetivo determinar se Philcoxia minensis exibe a síndrome da carnivoria e analisar os custos e benefícios desse hábito no contexto teórico sugerido por Thomas J. Givnish para a evolução da carnivoria. Para isso, fizemos uma detalhada descrição anatômica das folhas de P. minensis, na qual pudemos observar padrões evidentes de produção enzimática associada à digestão de invertebrados, em especial de fosfatases. Caracterizamos as estruturas glandulares responsáveis pela produção dessas enzimas, assim como os nematódeos que são considerados, até o momento, as únicas presas de P. minensis. Por fim, quanto à absorção de nutrientes derivados dos nematódeos, pudemos observar uma incorporação de 5% do nitrogênio das presas (Caenorhabditis elegans) em apenas 24h, e 15% em 48h em um experimento com isótopos estáveis. Para avaliar o balanço energético dessa espécie, analisamos de que forma características foliares associadas aos processos de fotossíntese e respiração se correlacionam. De maneira geral, encontramos forte correlação entre as capacidades fotossintéticas (Aarea e Amass) e os valores de LMA (quantidade de massa seca por unidade de área foliar) para as espécies não carnívoras, com um claro distanciamento dos indivíduos de P. minensis, que apresentaram taxas fotossintéticas extremamente baixas. Quanto às correlações entre os conteúdos de nitrogênio e de fósforo com as capacidades fotossintéticas, vimos que os indivíduos de P. minensis apresentaram taxas fotossintéticas extremamente baixas para os valores desses dois nutrientes e, embora uma tendência possa ser observada, não observamos correlações entre capacidades fotossintéticas e os conteúdos foliares de nitrogênio e fósforo. Por fim, conseguimos determinar conclusivamente a natureza carnívora de P. minensis, assim como pudemos posicionar essa espécie ao longo do espectro de economia foliar, tanto de forma local quanto em uma escala global. Nossos resultados ilustram o quanto ainda há para ser descoberto quanto à origem, à distribuição e à frequência da síndrome da carnivoria / Abstract: Carnivorous plants are plants that have the ability to capture and digest small animals, usually insects and other invertebrates. The studies with these plants began in the nineteenth century and until today it is unknown the underlying mechanisms that determine the evolution and the geographical distribution of these singularities. The cost--benefit models are, accordingly, acting as guidelines to various studies in recent decades and seem to be able to clarify many obscure points concerning the ecology and the evolution of these plants. The three species of the genus Philcoxia, endemic to campos rupestres -- fire prone and nutrient--poor environments usually associated with rocky outcrops and white sand formations -- have unique characteristics and adaptations that eventually led to several questions regarding the physiology of these plants. With growing accumulation of evidence, scholars started to consider the possibility that such plants could present active mechanisms for capturing and digesting prey. The present study aimed to determine if Philcoxia minensis exhibits the syndrome of carnivory and to analyze the costs and benefits of this habit in the theoretical context suggested by Thomas J. Givnish for the evolution of carnivory. In order to do so, we have made a detailed anatomical description of the leaves of P. minensis, in which we observed a clear pattern of enzyme production possibly associated with prey digestion, including phosphatases. We also characterized the glandular structures that are responsible for the production of the enzymes as well as the nematodes that are considered, until now, the only prey of P. minensis. Concerning the absorption of nutrients derived from prey, we observed an incorporation of 5% of the nitrogen of the nematodes (Caenorhabditis elegans) in 24h, and 15% in 48h in an experiment with stable isotopes. To evaluate the energy balance of this species, we analyzed correlations between leaf traits associated with the processes of photosynthesis and respiration. Generally speaking, we found a strong correlation between the photosynthetic capacity (Amass and Aarea) and the LMA (leaf mass per area) values for neighboring non--?carnivorous plants, with a distancing of P. minensis individuals, which showed very low photosynthetic rates. Regarding the correlations between the contents of nitrogen and phosphorus with photosynthetic capacities, we observed that the individuals of P. minensis showed extremely low photosynthetic rates for their nutrient concentrations and, although a tendency could be observed, there is no correlation between photosynthetic capacity and the foliar contents of nitrogen and phosphorus. Finally, we have conclusively determined the carnivorous nature of P. minensis and we placed this species along the leaf economics spectrum, both in local and global scale. Our results illustrate how much there is still to be discovered about the origin, distribution and frequency of the carnivorous syndrome / Mestrado / Ecologia / Mestre em Ecologia

In this work, I present a multi-isotopic study (carbon, nitrogen, sulfur, strontium and lead) and Re-Os geochronology in rocks and crude oils of the Sonda de Campeche Petroleum System (SCPS). Since crude oils are complicated chemical systems easily disturbed, the Re-Os isotopic system could be affected if secondary processes perturb crude oils. Therefore, the multi stable isotopic study allows the identification of the presence and grade of these secondary processes in crude oils. The δ13C values of crude oils from the SCPS distinguish between: 1) crude oils with the fingerprint of source rocks of hydrocarbons (-28.3 to -26.7 ‰), and 2) crude oils with the fingerprint of the reservoir rocks (-25.5 to -24.9 ‰). Similarly, the δ15N values reveal that crude oils, during migration or trapping processes mimic the isotopic composition of the reservoir rocks of the Ek-Balam Formation. Furthermore, the δ34S values of crude oils from the SCPS (-8.0 to -2.5 ‰) show an absence of a thermal sulfate reduction (TSR) signature, which likely means that the use of Re-Os systematics in crude oils and rocks in the SCPS is appropriate. Strontium and lead measurements show crude oils have an isotopic composition different from rocks from the Edzna Formation but similar to rocks of the Akimpech and Ek-Balam formations, indicating that crude oils received Sr and Pb from the trapping rocks during migration or trapping processes, producing a isotopic mixing trend with rocks of these formations. Specifically, the lead isotope composition allows the identification of a source of lead never recorded before, the Guichicovi Complex. The isotopic data suggest that this Grenville Complex has been feeding with detrital material to the sedimentary rocks from Bacab, Ek-Balam and Akimpech formations in the SCPS, and in consequence contributing to the final isotopic composition of crude oils as well. Re-Os geochronology of rocks from the Edzna and Akimpech formations (152 ± 4 Ma; and 158.6 ± 5.5 Ma, respectively) provides precise ages of deposition that coincide with the ages proposed in previous studies based on the fossil record. Re-Os geochronology in crude oils yield ages with low uncertainty and moderate MSWD values, reflecting a rapid formation and migration process that occurred during evolution of the SCPS. The age of crude oils (28.3 ± 5.5 Ma) broadly agrees with petroleum generation models proposed by PEMEX.

Seasonal long-distance bird migration between wintering and breeding grounds is oneof the most remarkable phenomena in the history of life on earth. Migration strategies androutes vary greatly. Some birds migrate in social groups whilst others migrate alone at night,some cross few hundreds of km whilst others cover thousands of km. Avian migration has beenstudied extensively nevertheless numerous important questions remain unanswered. This studyaims to contribute to the understanding of the genetic basis of the innate migratory program ofa common songbird.From results of classical crossbreeding and orientation experiments with captiveblackcaps (Sylvia atricapilla) we can be sure that songbird migration directions as well asdurations are traits that are being inherited genetically and most likely have a multi-locusgenetic architecture. The chosen model species for my project is the willow warbler(Phylloscopus trochilus), one of the most common leaf warblers in the Palearctic. The willowwarbler has a continuous breeding distribution from the coast of the Atlantic to the coast ofPacific. They overwinter in sub-Saharan Africa. Three subspecies have been recognized: P. t.trochilus (breeding in central/western Europe and migrating SSW to western Africa), P. t.acredula (breeding in northern and eastern Europe, migrating SSE to east and south Africa)and P. t. yakutensis (breeding east of Ural Mountains, presumably migrating to SouthernAfrica). Morphological differences across the willow warbler subspecies are subtle and it has been previously shown that genome wide FST is close to zero. The low level of neutral back-ground divergence offers a good system for studying the genetics of passerine migration. This report contributes with novel data on phenotypes and genotypes of the subspecies yakutensisstudied at Chaun river delta, at the very eastern range limit of the species. As a proxy for thewintering location of yakutensis I used C and N stable isotope signatures from winter grownfeathers and inferred wintering range to be in Southern Africa. I genotyped 36 yakutensis fromChaun on four nuclear markers, of which three are located on the only divergent regions thatdiffers between the migratory phenotypes in Europe + CLOCK gene (a candidate for timing ofmigration). Analyzes revealed that yakutensis, despite strong differences in migration direction,distance, timing and wintering ground location cannot be separated from acredula genetically.

Because nitrogen isotopes are fractionated along the soil-plant-insect-bat-guano pathway, it may be possible to reconstruct environmental and climatic changes reflected in the nitrogen isotopic composition of guano. A 1.5-m core of bat guano from Zidită Cave (western Romania) provides a record of climatic and anthropogenic influence on the regional nitrogen cycle and paleoenvironmental controls on nitrogen transforming processes. Increasing and decreasing trends of nitrogen isotopic composition (δ15N values) correspond well with changes in the influence of farming practices, deforestation, and forest expansion. These influences likely had a significant effect on the openness of the nitrogen cycle, resulting in changes in δ15N values of soil, plants, and ultimately guano. While δ15N values have gradually decreased since AD 1700, decadal trends towards more positive values at AD 1840 and 1920 coincide with increases in tree pollen (forest recovery). Additionally, the accumulation of relatively15N-depleted guano coincides with periods of increased fire frequency, deforestation, and crop/herbaceous pollen (agricultural practices). δ13C record of bulk guano indicates that carbon isotopic variation results from changes in water availability. Comparison of δ13C to δ15N indicates that there is a significant correlation between nitrogen and carbon isotopic composition of guano. When water availability was high (low δ13C values), δ15N values of bulk guano trend towards higher values. Although this connection to climate is the opposite of the findings from previous work correlating δ15N values of plant foliage and precipitation amount, the relationship between nitrogen isotopic values and water availability still appears to have merit. Based on these findings, δ15N of guano appears to be a signal for changes in N cycling of the Mada region that occurs, primarily in response to the precipitation received, further modified by intense changes in anthropogenic activity.

The marine ecosystem provides key resources to terrestrial organisms inhabiting oceanic islands. These subsidies of marine resources have the potential to affect species richness, ecology and productivity, especially on islands with high perimeter-area ratios. I investigated the impact and importance of marine subsidies on mammal diversity and diet on islands of British Columbia’s Central Coast. Insular mammal species richness was significantly correlated with island area and quantity of marine subsidy (wrack). However, mink and river otter island occupancy was unaffected by island-level covariates, whereas small mammals were more likely to occupancy islands closer together. Keen’s mice and food items were subsidized directly (i.e., consumption) and indirectly (i.e., fertilization) by marine resources. Beach-dwelling arthropods composed 33% of mouse diets. Furthermore, mouse and terrestrial arthropod abundances and stable isotope signatures (d13C and d15N) of food items were depleted moving inland from the beach. Finally, reproductive male mice consumed up to twice the marine-derived prey as females. Collectively, this work demonstrates that insular mammalian richness, as mediated by island-level factors, may be complex due to variation within populations and the recipient ecosystem (e.g., prey biomass). / Graduate

Biological and physical sampling of a 10km long, east-west transect was performed during 2007, off the coast of southeast Florida. Temperature and salinity measurements were recorded using a conductivity-temperature-depth (CTD) sensor, and current direction and magnitude measurements were recorded using an acoustic Doppler current profiler (ADCP). Zooplankton samples were collected, during the daytime, using a Tucker multiple net mid-water trawl, with 760μm mesh, at intended depths of ~25m and ~200m, at three stations along the transect. Laboratory analysis indicated that several currents and water masses influenced the density distribution of calanoid copepods and chaetognaths. During April and September 2007, a Subsurface Counter Current existed in conjunction with an offshore meander of the Florida Current. Physical data confirmed the presence of Continental Edge Water and Yucatan Water occupying different spatial and temporal scales, and the boundary between these two water masses existed as the western boundary of the Florida Current. Temperature and salinity profiles confirmed that the Subsurface Counter Current was composed of Continental Edge Water and not Yucatan Water. Therefore, the Subsurface Counter Current observed during the transect was not a cross section of a passing eddy caused by the meandering front of the Florida Current. Densities of both taxa were highest in the Subsurface Counter Current and the Intermediate water, while the lowest densities are found in the Florida Current. Calanoid copepod and chaetognath densities exhibited typical zooplankton trends for tropical and subtropical coastal waters. Densities were highly influenced by the physical parameters of each month. Highest densities were observed in April and the lowest in July/September, typically the nutrient limited season. Analysis by location showed that the calanoid copepod and chaetognath densities were highest inshore and decreased offshore. The Florida Current exhibited the lowest densities for both taxa, while the Subsurface Counter Current and Intermediate water had higher densities. Previously documented southward flow had been associated with an offshore meander of the Florida Current, but during May and July there was a Subsurface Counter Current and an onshore meander of the Florida Current. Densities of both taxa were still lowest in the Florida Current. The stable isotope values of the zooplankton were skewed because of the preservation media and it was not possible to determine if the currents and water masses were isotopically different, and thus creation of a correction factor for the preservation effect was not possible. The δ13C values were variable in magnitude and direction from the control for each taxon. The δ15N values were less variable, but increased from the control, rather than decrease, as was expected for each taxon.

The endangered Hawaiian monk seal has been undergoing dramatic population declines for several decades. These declines may be linked to food resources or environmental changes and this is reflected in the stable isotope analysis of the monk seals. The use of stable carbon (δ13C) and nitrogen (δ15N) isotope ratios on Hawaiian monk seal bone collagen samples collected from 1912 through 2006 determined that changes within the environment and food web of the Hawaiian monk seal may be factors contributing to the decrease in the population. Over the ninety-four year period the overall δ15N of the monk seals was depleted by approximately 3‰ and the δ13C had minimal changes. Monk seals located within the northern extent of the NWHI exhibited the most dramatic changes in stable isotopes. From 1923 through 2006 the δ15N of the Hawaiian monk seals within this area was depleted nearly 6‰, while δ13C was enriched by 2‰. This significant depletion in δ15N, along with the enrichment within the δ13C for the northern NWHI could be caused by an increase in the primary productivity within the area, leading to a shorter food web. This inverse relationship within the northern NWHI could also be a representation of the monk seals foraging more on benthic rather than pelagic prey, or foraging inshore rather than offshore in this region. This northern region was in contrast to the Central and southern islands within the NWHI. The central NWHI seals had nominal change in their δ15N and δ13C from 1912 to 2006; whereas, the southern NWHI seals exhibited a 3.5‰ depletion in δ15N and a nearly 1‰ depletion in δ13C over the span from 1951 through 2006. Within the central NWHI the juvenile monk seals were more depleted in δ15N as compared to the adult monk seals, which could indicate a prey base change for these seals. Within the southern NWHI there was a significant difference within δ15N and δ13C over the decades of the study which could indicate a decrease in the regional productivity. The adult monk seals within the southern region also had an increase in δ15N which could be a indicator of starvation for the seals within this region. Stable carbon and nitrogen isotopes indicate modern monk seals (2000-2006) foraged on a number of different teleost, crustacean, eel, and cephalopod species, correlating to earlier and current studies being conducted on the food sources of the Hawaiian monk seal.

Mangrove communities are unique environments that line coastlines in tropical and subtropical latitudes. In Florida, four mangrove tree species dominate these communities and are accompanied by other primary producers, infaunal, epifaunal, and juvenile faunal species that together form the base of a complex, chiefly detritus-based food web. In an effort to evaluate mangrove communities in Port Everglades, Florida, tissue samples were taken from a diversity of mangrove- associated producer and consumer species from three mangrove sites. Stable carbon and nitrogen isotope ratios were used to establish patterns of energy flow of mangrove material, examine the influence of detrital material, and identify isotopic differences among mangrove species. R.mangle was the most depleted in δ13C, -34.11 to -26.19‰, while C.erectus was the most enriched, -29.91 to -25.30‰. This pattern mirrors the documented pattern of proximity to the waterline, but this pattern was not the same in δ15N, as C.erectus exhibited the narrowest range of δ15N values, -1.95 to 5.40‰. Significant differences were found in δ15N and δ13C signatures of the mangrove species among the tissue types, sampling sites, and trophic linkages among three sample sites, which could indicate differences between natural and anthropogenic influences, such as increased nitrate from a nearby residential area. Specifically, site 1, the only site located directly on the Intracoastal Waterway, differed significantly from sites 2 and 3, both of which were indirectly connected to the waterway. Results also established unique trophic levels, with primary producers at the bottom and carnivorous fish at the top. Slight differences among the trophic dynamics, such as a shift in diet specifically with fish species, among the sites revealed a possible influence of restricted tidal flow from mangrove communities.