Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-03-30T17:49:45Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) taiana oliveira - DISSERTAÇÃO.pdf: 4036407 bytes, checksum: b4f85048cc1a642722cd6e2d3778433b (MD5) / Made available in DSpace on 2016-03-30T17:49:45Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) taiana oliveira - DISSERTAÇÃO.pdf: 4036407 bytes, checksum: b4f85048cc1a642722cd6e2d3778433b (MD5) Previous issue date: 2015-07-17 / CNPQ / Interferências antrópicas no estuário do rio Timbó (Paulista-PE) representaram forçantes que modificaram as características hidrodinâmicas e geoquímicas desta bacia hidrográfica. Nesta pesquisa, as mudanças ambientais são abordadas por estudos micropaleontológicos, através da assembleia de foraminíferos bentônicos, com apoio de estudos geoquímicos, inclusive isotópicos, ambos a partir de testemunhos de sondagem de fundo executada no estuário deste rio.A coleta do testemunho foi realizada em dezembro de 2012 e dezembro de 2013, utilizando um equipamento constituído de tubo de PVC com 50 mm de diâmetro, alcançando a profundidade de 87 cm e 90 cm para dados isotópicos.Este perfil cobriu cronologicamente o período desde fins do século XIX à primeira década do século XXI. Os resultados, apoiados em estudos estatísticos, indicaram que a espécieQuinqueloculina lamarckianaparece restrita a condições de maior hidrodinâmica, marcadas por quartzo > 20% em sedimento total. Ammonia tepidamostrou-se confiável espécie bioindicadora de degradação ambiental, acompanhando concentrações de Pb nos sedimentos.Discorbis floridanatambém se mostrou boa indicadora ambiental, em sedimentações mais recentes, acompanhando a degradação ambiental desde as últimas décadas. As modificações ambientais neste estuário, sobretudo resultantes de interferências antrópicas, se mostraram bem rastreáveis através do estudo de isótopos deδ13C e δ18O a partir dos carbonatos dos exoesqueletos dos foraminíferos bentônicos estudados. / Anthropogenic interference in the estuary of Timbó river (Paulista-PE) changed the hydrodynamic and geochemical characteristics of the watershed. In this study, we evaluated the environmental changes by micropaleontologicalstudies through the assemblagesof benthic foraminifera, supported by geochemical studies, including isotopic evaluation, both from bottom drill core executed in the estuary of the river. The collection of core was held in December 2012 and December 2013, using a device made of PVC pipe with50 mm diameter, reaching a depth of 87 cm and 90 cm for isotopic data.This core chronologically covered the period from late nineteenth century to the first decade of this century. The results, supported by statistical studies, indicated thatQuinqueloculina lamarckianaseems restricted to conditions of greater hydrodynamics, marked by quartz > 20% in total sediment.Ammonia tepidaseems to be a reliable bioindicator of environmental degradation, following Pb concentrations in sediments.Discorbis floridanawas also a good environmental indicator, in more recent sedimentation, following the environmental degradation in the last decades. The environmental changes in this estuary, especially resulting from anthropogenic interference were well traceable through the study of δ13C and δ18O isotopes from the carbonates of the exoskeletons of benthic foraminifera studied.

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.

Seagrass habitats are highly productive ecosystems that support marine food webs and provide essential habitat for a variety of species. Seagrass coverages are declining in abundance worldwide. For southeastern Florida in particular, one of the main causes of the decline is disturbance from dredging and removal of substrate. Seagrass beds at three locations in the vicinity of Port Everglades, Florida were assessed for their trophic contribution to the marine organisms in the area. Seagrasses, algae, invertebrates, and vertebrates from the beds were identified and analyzed for stable carbon and nitrogen isotope ratios to determine their contribution as a food source. Significant differences were found in both δ13C and δ15N between both seagrass species and among the three sites. The δ13C of Johnson’s seagrass Halophila johnsonii ranged from -16.28 to -11.27‰ while shoal grass Halodule wrightii ranged from -15.78 to -13.36‰. The δ15N for H. wrightii were more constrained than those of H. johnsonii, 4.69 to 7.08‰ versus 0.80 to 7.86‰, respectively. Neither seagrass species appeared to be a dominant food source for marine organisms at all three study sites. However, the δ13C and δ15N of both seagrass species, Halophila johnsonii and Halodule wrightii, did fall in the fractionation range of potential consumers, -28.78 to -17.11‰ and 1.96 to 12.63‰, indicating that these animals could be ingesting pieces of seagrass while grazing on epiphytes and other primary producers in the area. Epiphytes found on the seagrass blades appeared to be a greater trophic contributor to local organisms. So while the seagrass species in question may not have been major contributors to the diet of many of the local consumers, the seagrasses nontheless played a vital role as habitat for the epiphytes that did serve as a trophic resource in these communities.

This study found evidence of intermittent, multi-year residency periods in northern fur seals (Callorhinus ursinus) using stable isotope ratios in vibrissae and canine teeth. Northern fur seals migrate from the Bering Sea during summer months to lower latitudes and slightly warmer waters of the northeastern Pacific Ocean and California Current in the winter. To determine the length of time spent away from the Bering Sea, growth rate was estimated using the covarying oscillations δ13C and δ15N, estimated to be 0.09 mm/day. The δ13C and δ15N in vibrissae from 30 male fur seals showed a minimum of 13 separate periods of stable covariance covering 3.25+ cm, indicating at least 1 year in warmer, less productive waters of the northeastern Pacific Ocean. The vibrissae isotope ratios were used in conjunction with δ18O from tooth dentin growth layer groups of 20 male northern fur seals; they showed significant enrichment in δ18O in 50% of the animals at age 1-2 years, which indicates extended periods of time spent in lower latitudes in the North Pacific Ocean as δ18O is typically enriched in warmer, less productive waters. Significant changes in δ18O were found to be ~ 0.2‰ enrichment per 10º south latitude, while longitude was found to have 0.2‰ enrichment per 50˚ East longitude. These data show that latitudinal changes, those related to the southerly migration from the Bering Sea to the northeastern Pacific Ocean, are a stronger factor in the shifts in dentinal δ18O than longitudinal shifts. These intermittent periods of occupation are important when estimating population abundance of northern fur seals, especially pups and juveniles.

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).

Lake Victoria situated in East Africa faces an acute problem with eutrophication. Many reasons like agricultural production, industrialization, anthropogenic processes, the introduction of species, and economic activities have caused a stress to the overall well-being of the lake. Excess carbon, nitrogen, and phosphorus drive an increase in productivity which affects eutrophication. Previous studies on sediments and nutrient concentrations in the lake have concluded that nutrient concentrations increase due to release from the catchment. This study focuses on catchment sediments collected from four different sites and compares the results with sediments from two additional sites in the lake. The sediment core from Siaya indicates the highest concentrations of TOC (180 g/kg), TN (13 g/kg) and TP (17000μg/L). It is a rural site and poor agricultural practices such as the burn and slash, use of too many fertilizers, clearance of land, atmospheric deposition and precipitation increase elemental concentrations in the sediments compared to the more urban sites. In the lake sediments, the BILL core had higher concentrations of TP (430g/kg) and TN (16 g/kg) compared to the other site (LV-95) which is located far away from the margins of the lake. This core, however, had high TOC levels (180g/kg). The increase of nutrient levels in lake sediments is thought to be due to non-point sources from the catchment. Analyses of stable carbon isotope were used to infer the different organic matter source in the sediments. Based on the range of values for δ13C vs. C/N it is inferred that aquatic algal production and C4 vascular plants are the dominant sources for the organic matter input. The chemical characterization of catchment and lake sediments provides a qualitative link to nutrient influx and eutrophication in the lake.

Komořany Lake, regarded as one of the most important sites of the Czechoslovak Quaternary, was situated at the southern foot of the Krušné hory Mountains, northwest from the Starý Most town, between the villages of Souš, Komořany, Ervěnice, Dřínov, Albrechtice, Černice and Dolní Jiřetín. Due to its size, Komořany Lake belonged to the largest bodies of water in the Czechoslovak Republic (25 km2 ) and due to the quantity of organogenic sediments get into the focus of paleoecologists. Gyttji sediments which occupy comparatively thick position in the lake infilling, formed a continuous record from the Last Glacial period to the Subatlantic period and up to now have been processed mainly from the paleoecological point of view. In this work the organogenic sediments are studied from the sedimentary record using modern geochemical methods (TOC/TN and d13C) for the first time in Komořany Lake history. The work was based on profiles (PK-1-C, PK-1-Ch, PK-1-I and PK-1-W) which were taken between 1977-1983 before a complete exploitation of Komořany Lake sediments as a result of coal mining in the Most Basin in the 1980's.

It has been estimated that approximately half of all anthropogenic fossil fuel carbon dioxide (CO2) emissions have been absorbed by the oceans. Air-sea gas exchange of CO2 and the buffering capacity of seawater allows the oceans to store significant amounts of dissolved inorganic carbon (DIC; ~38,000 GtC). The Arctic Ocean is currently warming at double the rate of the rest of the planet, yet the effect of climate change on the Arctic marine carbon cycle remains unconstrained. Recent work suggests that Arctic marine environments are a carbon sink for the majority of the year, and plays a key role in storing anthropogenic carbon below the mixed layer. Baffin Bay is a semi-enclosed, Arctic basin that supplies cold surface water to the Labrador Sea; a critical region for North Atlantic deep-water formation. While the physical oceanography of surface Baffin Bay is well characterized, less is known about deep water formation mechanisms and its ventilation age. The few residence times for Baffin Bay Deep Water (BBDW) range widely from 20-1450 years. Improved residence time estimates are essential for understanding the role Baffin Bay plays in the Arctic carbon cycle and how this region will respond to climate change. Radiocarbon (D14C) and stable carbon (δ13C) measurements of DIC are powerful tools for parameterizing water mass sources, aging and residence times. However, very few DIC Δ14C and d13C data have been reported in the Arctic Ocean, comprising only a handful of stations in the Eurasian Basin, Canadian Basin, and Beaufort Sea. With this goal in mind, we conducted a study in which DIC samples were collected aboard the CCGS Amundsen in 2019 for δ13C and Δ14C analysis. DIC δ13C and D14C values ranged from 0.68‰ to +1.90‰ and -90.0‰ to +29.8‰, respectively. Surface DIC δ13C values were +0.69‰ to +1.90‰, while deep (>100m) d13C values ranged -0.01 to -0.68‰. Significant linear correlations were found for δ13C and potential density, suggesting DIC δ13C is an effective water mass and carbon source tracer in Baffin Bay. Surface DIC Δ14C values ranged -5.4‰ to +22.9‰, while deep DIC (>1400m) DIC Δ14C averaged -82.2 8.5‰ (n = 9). Much larger surface to deep gradients in DIC Δ14C are observed in Baffin Bay vs. that of the North Atlantic Ocean, suggesting significant aging of BBDW. Next, we used the potential alkalinity method (Palk) and the ΔC* method to quantify the amount of “bomb” 14C and anthropogenic C (DICanth) to model “natural” DIC Δ14C profiles. Both Palk and ΔC* proxies had high errors in cold, low salinity surface water. In particular, surface (<400m) Δ14Cbomb was overestimated at all stations. However, both proxies did not indicate Δ14Cbomb or DICanth contributions below 1000m. Two 14C residence times were estimated based on two proposed mechanisms of BBDW formation. A residence time of 690 +/- 35 years was estimated assuming surface brine rejection in Nares Strait is the main source of BBDW. Another plausible source of BBDW is the entrainment of dense north Atlantic Water over Davis Strait mixed with brine enriched surface water. A comparison of DICanth and Δ14Cbomb corrected deep DIC Δ14C values from the North Atlantic (GO SHIP A16N) to BBDW, resulted in a residence time of 360 +/- 35 years. These residence times (360-690 years) provide new constraints on the ventilation age of deep Baffin Bay and suggest this basin has the potential to store carbon for centuries.

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.