Adsorção e dessorção de fosfato em latossolo vermelho sob diferentes tipos de uso com adição de sacarose

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Condições termodinâmicas de eventos de precipitação extrema em Belém-PA durante a estação chuvosa

As condições termodinâmicas de uma região são muito importantes para o desenvolvimento da convecção úmida profunda, principalmente nas regiões tropicais. Portanto, o objetivo deste trabalho foi o de entender e caracterizar o papel das condições termodinâmicas da atmosfera durante os eventos de precipitações extremas na estação chuvosa, no período de 1987 a 2007, em Belém (PA). Os resultados mostram que as precipitações extremas, em sua maioria (56%) apresentam um ambiente precursor com forte instabilidade, indicada pelos altos valores de CAPE (acima de 1000 J/kg) e valores significativos dos índices de instabilidade. Houve, contudo, eventos com baixos valores de CAPE na sondagem das 1200 UTC do dia do evento, mas valores maiores na véspera, o que indica que a chuva em questão pode ter começado na madrugada e ter perdurado por várias horas, atravessando a hora da sondagem, explicando a queda deste parâmetro. Os índices de instabilidade K, TT e LI apresentaram uma boa representação do ambiente, prognosticando as tempestades com chuvas fortes com índice de acerto de até 74%, se levados em conta os eventos em que todos os índices apontavam os mesmos resultados e indicavam forte instabilidade. As condições termodinâmicas de forte instabilidade ajudam a promover, mas não são as únicas responsáveis pelas tempestades convectivas com precipitações extremas.

Environmental sensitivity index (ESI) mapping of oil spill in the amazon coastal zone: the PIATAM Mar project

A importância do monitoramento ambiental é medida pelos vários casos de derramamentos de óleo ocorridos no mundo durante as últimas três décadas. Isto tem incentivado as empresas e órgãos do governo envolvidos na prevenção e combate a estes acidentes a aperfeiçoarem cada vez mais os métodos, tanto preventivos como corretivos, para a minimização dos danos gerados por acidentes com derramamento de óleo. Este trabalho objetiva contextualizar de forma histórica como os acidentes com derramamento de óleo propiciaram o desenvolvimento de pesquisa tecnológica a partir de parcerias entre empresas de petróleo, agências de governo, universidades e institutos de pesquisa no Brasil, em especial na zona costeira Amazônica. Como resultado, índices de sensibilidade ambiental ao derramamento de óleo (ISA) foram definidos especialmente para a Amazônia costeira, onde processos fluviais e marinhos se encontram na foz do maior rio do mundo, o rio Amazonas. Perspectivas de pesquisa e respostas de emergência a acidentes são apresentadas, a fim de se conservar a diversidade socioambiental da mais importante região tropical do planeta.

Comportamento de lek, frugivora e dispersão de sementes por Manacus Manacus (Linnaeus 1766, Pipridae) em áres de restinga no sudeste do Brasil

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Monitoramento das irregularidades ionosféricas e cintilação dos sinais GNSS: em tempo real e pós-processado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mineralogia da fração argila dos solos do Planalto Ocidental Paulista

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reproductive biology of the smooth butterfly ray Gymnura micrura

This study provides the first detailed information on the reproductive biology of the smooth butterfly ray Gymnura micrura. A total of 905 individuals were sampled, 377 of which were used for the reproductive study. Juveniles accounted for 75% of the sample, but all life cycle stages were present in the study area. The disc width at which 50% were mature (WD50)was estimated at 269 and 405 mm for males and females, respectively. The WD50V(based on the onset of vitellogenesis) was estimated at 359 mm. Uterine fecundity (mean +/- s.d. = 3.8 +/- 1.3; range: 16) was positively correlated with female size. A 3564% gain in mean wet mass was observed from egg to full-term embryo in utero. Size at birth ranged from 135 to 175 mm WD (19.5 to 55.0 g), with a mean of 165.1 mm WD (43.3 g). The embryo sex ratio was not significantly different from 1:1. The ovaries of pregnant females were undergoing vitellogenesis during gestation, with females ready to ovulate soon after parturition. Gymnura micrura may have an asynchronous reproductive cycle, with females reproducing continuously throughout the year.

Photochemie der Troposphäre in niedrigen und mittleren Breiten: Die Rolle von Konvektion

Ozon (O3) ist in der Atmosphäre ein wichtiges Oxidanz und Treibhausgas. Während die höchsten Konzentrationen in der Stratosphäre beobachtet werden und die vor der gefährlichen UV-Strahlung schützende Ozonschicht bilden, können sich signifikante Änderungen der Ozon-Konzentration in der Region der Tropopause auf das Klima der Erde auswirken. Des Weiteren ist Ozon eine der Hauptquellen für das Hydroxylradikal (OH) und nimmt damit entscheidend Einfluss auf die Oxidationskraft der Atmosphäre. Der konvektive Transport von Ozon und seinen Vorläufergasen aus Regionen nahe der Erdoberfläche in die freie Troposphäre beeinflusst das Budget dieser Spezies in der Tropopausenregion.rnDie Datengrundlage der Studie in der vorliegenden Arbeit basiert auf den flugzeuggetragenen Messkampagnen GABRIEL 2005 (Suriname, Südamerika) sowie HOOVER I 2006 und HOOVER II 2007 (beide in Europa). Mit dem zur Verfügung stehenden Datensatz wird das Ozonbudget in der freien, unbelasteten Hintergrundatmosphäre und in der durch hochreichende Konvektion gestörten, oberen Troposphäre untersucht. Anhand der auf in-situ Messungen von O3, NO, OH, HO2 und dem aktinischen Strahlungsfluss basierten Berechnung der Netto-Ozonproduktionsrate (NOPR) werden für das Messgebiet Ozontendenzen in der unbelasteten Troposphäre abgeleitet und mit Simulationen des globalen Chemie-Transport-Modells MATCH-MPIC verglichen. Mit Hilfe zweier Fallstudien in den Tropen in Südamerika und den mittleren Breiten in Europa werden die Auswirkungen von hochreichender Konvektion auf die obere Troposphäre quantifiziert.rnDie Ergebnisse zeigen für die Grenzschicht in niedrigen und mittleren Breiten eine eindeutige Tendenz zur Produktion von Ozon, was für den tropischen Regenwald in der Messregion nicht der allgemeinen Erwartung entsprach, nach der diese Region durch die Zerstörung von Ozon charakterisiert sein sollte. In der oberen Troposphäre ab etwa 7 km wird für die beiden Regionen eine leichte Tendenz zur Ozonproduktion beobachtet. Signifikante Unterschiede zeigen die Ergebnisse für die mittlere Troposphäre. Während die Tropen in dieser Region durch eine eindeutige Tendenz zur Zerstörung von Ozon charakterisiert sind, lässt sich über den mittleren Breiten zwar eine hohe photochemische Aktivität aber keine derart klare Tendenz feststellen. Die hohen Breiten zeichnen sich durch eine neutrale Troposphäre in Bezug auf die Ozontendenz aus und weisen kaum photochemische Aktivität auf. Der Vergleich dieser Ergebnisse mit dem MATCH-MPIC Modell zeigt in weiten Teilen der Messregionen eine grundlegende Übereinstimmung in der Tendenz zur Produktion oder Zerstörung von Ozon. Die absoluten Werte werden vom Modell aber generell unterschätzt. Signifikante Unterschiede zwischen in-situ Daten und Modellsimulationen werden in der Grenzschicht über dem tropischen Regenwald identifiziert.rnDer Einfluss der Konvektion ist durch eine signifikant erhöhte NOPR gekennzeichnet. In dieser Arbeit wird in den Tropen mit einem Median-Wert von 0.20 ppbv h−1 eine um den Faktor 3.6 erhöhte NOPR im Vergleich zur ungestörten oberen Troposphäre abgeschätzt. In den mittleren Breiten führt die um eine Größenordnung höhere NO-Konzentration zu einem Wert von 1.89 ppbv h−1, was einer Überhöhung um einen Faktor 6.5 im Vergleich zum ungestörten Zustand entspricht. Diese Ergebnisse zeigen für beide Regionen in der oberen Troposphäre eine erhöhte Ozonproduktion als Folge konvektiver Aktivität. rnrnHochreichende Konvektion ist zudem ein sehr effektiver Mechanismus für den Vertikaltransport aus der Grenzschicht in die obere Troposphäre. Die schnelle Hebung in konvektiven Wolken führt bei Spurengasen mit Quellen an der Erdoberfläche zu einer Erhöhung ihrer Konzentration in der oberen Troposphäre. Die hochgradig löslichen Spurenstoffe Formaldehyd (HCHO) und Wasserstoffperoxid (H2O2) sind wichtige Vorläufergase der HOx-Radikale. Es wird angenommen, dass sie aufgrund ihrer Löslichkeit in Gewitterwolken effektiv ausgewaschen werden.rnIn der vorliegenden Arbeit wird eine Fallstudie von hochreichender Konvektion im Rahmen des HOOVER II Projekts im Sommer 2007 analysiert. Am 19.07.2007 entwickelten sich am Nachmittag am Südostrand eines in nordöstlicher Richtung ziehenden mesoskaligen konvektiven Systems drei zunächst isolierte konvektive Zellen. Flugzeuggetragene Messungen in der Aus- und der Einströmregion einer dieser Gewitterzellen stellen einen exzellenten Datensatz bereit, um die Auswirkungen von hochreichender Konvektion auf die Verteilung verschiedener Spurengase in der oberen Troposphäre zu untersuchen. Der Vergleich der Konzentrationen von Kohlenstoffmonoxid (CO) und Methan (CH4) zwischen der oberen Troposphäre und der Grenzschicht deutet auf einen nahezu unverdünnten Transport dieser langlebigen Spezies in der konvektiven Zelle hin. Die Verhältnisse betragen (0.94±0.04) für CO und (0.99±0.01) für CH4. Für die löslichen Spezies HCHO und H2O2 beträgt dieses Verhältnis in der Ausströmregion (0.55±0.09) bzw. (0.61±0.08). Dies ist ein Indiz dafür, dass diese Spezies nicht so effektiv ausgewaschen werden wie angenommen. Zum besseren Verständnis des Einflusses der Konvektion auf die Budgets dieser Spezies in der oberen Troposphäre wurden im Rahmen dieser Arbeit Boxmodell-Studien für den Beitrag der photochemischen Produktion in der Ausströmregion durchgeführt, wobei die gemessenen Spezies und Photolysefrequenzen als Randbedingungen dienten. Aus den Budgetbetrachtungen für HCHO und H2O2 wird eine Auswascheffizienz von (67±24) % für HCHO und (41±18) % für H2O2 abgeschätzt. Das für H2O2 überraschende Ergebnis lässt darauf schließen, dass dieses Molekül in einer Gewitterwolke deutlich effektiver transportiert werden kann, als aufgrund seiner hohen Löslichkeit aus der Henry-Konstanten zu erwarten wäre. Das Ausgasen von gelöstem H2O2 beim Gefrieren eines Wolkentropfens, d.h. ein Retentionskoeffizient kleiner 1, ist ein möglicher Mechanismus, der zum beobachteten Mischungsverhältnis dieser löslichen Spezies in der Ausströmregion beitragen kann.

The Samoa Hurricane, 15-16 March 1889

Analysing historical weather extremes such as the tropical cyclone in Samoa in March 1889 could add to our understanding of extreme events. However, up to now the availability of suitable data was limiting the analysis of historical extremes, particularly in remote regions. The new “Twentieth Century Reanalysis” (20CR), which provides six-hourly, three-dimensional data for the entire globe back to 1871, might provide the means to study this and other early events. While its suitability for studying historical extremes has been analysed for events in the northern extratropics (see other papers in this volume), the representation of tropical cyclones, especially in early times, remains unknown. The aim of this paper is to study to the hurricane that struck Samoa on 15-16 March 1889. We analyse the event in 20CR as well as in contemporary observations. We find that the event is not reproduced in the ensemble mean of 20CR, nor is it within the ensemble spread. We argue that this is due to the paucity of data assimilated into 20CR. A preliminary compilation of historical observations from ships for that period, in contrast, provides a relatively consistent picture of the event. This shows that more observations would be available and implies that future versions of surface-based reanalyses might profit from digitizing further observations in the tropical region.

Lower-tropospheric humidity: climatology, trends and the relation to the ITCZ

The tropical region is an area of maximum humidity and serves as the major humidity source of the globe. Among other phenomena, it is governed by the so-called Inter-Tropical Convergence Zone (ITCZ) which is commonly defined by converging low-level winds or enhanced precipitation. Given its importance as a humidity source, we investigate the humidity fields in the tropics in different reanalysis data sets, deduce the climatology and variability and assess the relationship to the ITCZ. Therefore, a new analysis method of the specific humidity distribution is introduced which allows detecting the location of the humidity maximum, the strength and the meridional extent. The results show that the humidity maximum in boreal summer is strongly shifted northward over the warm pool/Asia Monsoon area and the Gulf of Mexico. These shifts go along with a peak in the strength in both areas; however, the extent shrinks over the warm pool/Asia Monsoon area, whereas it is wider over the Gulf of Mexico. In winter, such connections between location, strength and extent are not found. Still, a peak in strength is again identified over the Gulf of Mexico in boreal winter. The variability of the three characteristics is dominated by inter-annual signals in both seasons. The results using ERA-interim data suggest a positive trend in the Gulf of Mexico/Atlantic region from 1979 to 2010, showing an increased northward shift in the recent years. Although the trend is only weakly confirmed by the results using MERRA reanalysis data, it is in phase with a trend in hurricane activity�a possible hint of the importance of the new method on hurricanes. Furthermore, the position of the maximum humidity coincides with one of the ITCZ in most areas. One exception is the western and central Pacific, where the area is dominated by the double ITCZ in boreal winter. Nevertheless, the new method enables us to gain more insight into the humidity distribution, its variability and the relationship to ITCZ characteristics.

Sedimentological and geochemical characteristics of upper Cretaceous and lower Tertiary sediments of ODP Hole 108-661A

Based on sedimentological and geochemical data, the Upper Cretaceous and Tertiary sequence at Ocean Drilling Program Site 661 was subdivided into four intervals: Interval I (Campanian age) is characterized by sediments deposited below the calcite compensation depth (CCD) inside a high-productivity area and well-oxygenated bottom waters, indicated by the absence of carbonate, the major occurrence of zeolites and opal-CT, and intense bioturbation. Very fine-grained siliciclastic sediments and the lack of any erosional features suggest a low-energy environment. The terrigenous fraction was probably supplied by winds from the nontropical areas in South Africa. Interval II (Maestrichtian age) is characterized by high-amplitude variations in the carbonate content indicative of a deposition above the CCD, superimposed by (climate-controlled) short-term fluctuations of the CCD. The absence of both zeolites and opal-CT imply a position of Site 661 outside high-productivity areas. The first occurrence of higher amounts of kaolinite (especially during the middle Maestrichtian) suggests the onset of a terrigenous sediment supply from tropical areas. Interval III (between uppermost Cretaceous to early Tertiary) is characterized by the absence of carbonate and zeolites, interpreted as deposition below the CCD and outside an oceanic high-productivity belt. The kaolinite-over-illite dominance suggests a terrigenous sediment supply from tropical areas. Interval IV (between early Tertiary and Miocene age) is characterized by the occurrence of black manganeserich layers, major nodules/pebbles, and erosional surfaces, indicating phases of extremely reduced sediment accumulation and bottom-current activities. In the lower part of this interval (?Eocene age), higher amounts of zeolites occur, which suggest a higher oceanic productivity caused by equatorial upwelling. The source area of the terrigenous sediment fraction at Site 661 was the tropical region of northwest Africa, as suggested by the kaolinite-over-illite dominance.

Neogene planktonic foraminifers from Wombat and Exmouth Plateau

Diverse, warm-water planktonic foraminiferal faunas prevailed on the Wombat and Exmouth plateaus during the Neogene, in spite of the northward drift of Australia across 10° to 15° latitude since the early Miocene. Invasions of cool-water species occurred during periods of global cooling in the late middle Miocene, late Miocene, and Pleistocene, and reflect periods of increased northward transport of cool surface water, probably via the West Australian Current. The sedimentary record of the Neogene on Wombat and Exmouth Plateau is interrupted by two hiatuses (lower Miocene, Zone N5, and upper middle to upper Miocene, Zones N15-N17), and one redeposited section of upper Miocene to uppermost Pliocene sediments. Mechanical erosion or nondeposition by increased deep-water flow or tilting and uplift of Wombat and Exmouth plateaus, resulting in sediment shedding, are the most likely explanations for these Miocene hiatuses, but which of these processes were actually operative on the Wombat and Exmouth plateaus is uncertain. The redeposited section of upper Miocene to uppermost Pliocene sediments in Hole 761B, however, certainly reflects a latest Pliocene period of uplift and tilting of the Wombat Plateau. An important finding was the occurrence of Zone N15-correlative sediments in Hole 762B without any representative of Neogloboquadrina. Similar findings in Java and Jamaica indicate that the earliest spreading of Neogloboquadrina acostaensis in the tropical region resulted from migration. The evolution of this species, therefore, must have taken place in higher latitudes. I suggest that Neogloboquadrina acostaensis evolved from Neogloboquadrina atlantica in the North Atlantic within Zone NN9, but how and where in the region this speciation took place is still uncertain

Direct seeding to restore rainforest species: Microsite effects on the early establishment and growth of rainforest tree seedlings on degraded land in the wet tropics of Australia

Reforestation in tropical areas is usually attempted by planting seedlings but, direct seeding (the artificial addition or sowing of seed) may be an alternative way of accelerating forest recovery and successional processes. This study investigated the effects of various sowing treatments (designed to create different microsite conditions for seed germination) and seed sizes on the early establishment and growth of directly sown rainforest tree species in a variety of experimental plots at three sites in the wet tropical region of north-cast Queensland, Australia. The different sowing treatments were found to have significant effects on seedling establishment. Broadcast sowing treatments were ineffective and resulted in very poor seedling establishment and high seed wastage. Higher establishment rates occurred when seeds were buried. Seed size was found to be an important factor affecting establishment in relation to micro-site condition. In general, larger seeded species had higher establishment rates at all three sites than species of small and intermediate seed size, but only in sowing treatments where seeds were buried. Overall these results suggest that direct sowing of seed can be used as a too] to accelerate recolonisation of certain rainforest tree species on degraded tropical lands, but initial success will be dependent on the choice of sowing method and its suitability for the seed types selected. The results also indicate that the recruitment of naturally dispersed tree species at degraded sites is likely to be severely limited by the availability of suitable microsites for seed germination. Consequently the natural recovery of degraded sites via seed rain can be expected to be slow and unpredictable, particularly in areas where soil compaction has occurred. (c) 2006 Elsevier B.V. All rights reserved.

Parâmetros biológicos de Herpsilochmus pectoralis Sclater 1857 (Aves: Thamnophilidae) em fragmentos de mata atlântica do Nordeste do Brasil

The study of birds represents an important tool for the understanding of the processes involved in behavioral and morphological patterns. The species we have studied belongs to Thamnophilidae family, the third largest family restricted to the Neotropic ecozone. They are popularly known as antbirds and comprise 209 species. A large portion of the species has cryptic behavior, making the acoustic communication an important tool for maintaining contact among birds. Herpsilochmus pectoralis Sclater 1857 has evident sexual dimorphism, measured between 10 and 12 cm height and it is found in forest fragments in the Northeast and it is also categorized as vulnerable to extinction process. This study was conducted in three sandbank fragments on the east coast of the state of Rio Grande do Norte, Brazil. With the help of tape recordings between 2006 and 2012 it was possible to describe and characterize the sing of H. pectoralis. The sing from male birds has more and longer length than the female sing (16% of dimorphism). No differences were found in the dominant frequency between the sexes. We describe four types of calls from this species repertoire. Through capturing with ornithological nets between 2009 and 2012 it was possible to describe and compare the morphology of H. pectoralis. The species have shown lower corporal mass in the dry season. The young birds showed morphometric similarities in comparison to adults. The species has no accentuated dimorphism in their morphometric characteristics. The young ones with flying capabilities have morphometric characteristics of adults, even though they do not show a characteristic adult plumage. The moult pattern in the species is a characteristic of tropical birds, but it shows short reproductive period, typical of temperate species. Even being in the tropical region, the species suffers with seasonal rainfall, which influences their reproductive phenology and moult (remex and rectrix) cycle. Thus, this dissertation provides information on the biology of H. pectoralis to support the understanding of the relationship of this species to the environment and also to know the variations of morphology and vocal aspects, in order to understand patterns and general characteristics of Thamnophilidae.

Effects of time-controlled and continuous grazing on total herbage mass and ground cover

Grazing practices in rangelands are increasingly recognized as a management tool for environmental protection in addition to livestock production. Long term continuous grazing has been largely documented to reduce pasture productivity and decline the protective layer of soil surface affecting environmental protection. Time-controlled rotational grazing (TC grazing) as an alternative to continuous grazing is considered to reduce such negative effects and provides pasture with a higher amount of vegetation securing food for animals and conserving environment. To research on how the grazing system affects herbage and above ground organic materials compared with continuous grazing, the study was conducted in a sub-tropical region of Australia from 2001 to 2006. The overall results showed that herbage mass under TC grazing increased to 140% in 2006 compared with the first records taken in 2001. The outcomes were even higher (150%) when the soil is deeper and the slope is gentle. In line with the results of herbage mass, ground cover under TC grazing achieved significant higher percentages than continuous grazing in all the years of the study. Ground cover under TC grazing increased from 54% in 2003 to 73%, 82%, and 89% in 2004, 2005, and 2006, respectively, despite the fact that after the high yielding year of 2004 herbage mass declined to around 2.5 ton ha^(−1) in 2005 and 2006. Under continuous grazing however there was no significant increase over time comparable to TC grazing neither in herbage mass nor in ground cover. The successful outcome is largely attributed to the flexible nature of the management in which grazing frequency, durations and the rest periods were efficiently controlled. Such flexibility of animal presence on pastures could result in higher water retention and soil moisture condition promoting above ground organic material.