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"Análise do conhecimento de conteúdos fundamentais de Genética e Biologia Celular apresentado por graduandos em Ciências Biológicas".; Analysis of the knowledge o fundamental contents of Genetics and Cellular Biology presented by graduating students in Biological Sciences.

Primon, Catia Sueli Fernandes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/12/2005 Português
Relevância na Pesquisa
45.94%
A Biologia hoje é a mais comentada ciência e a que ocupa maior espaço na mídia. No entanto, isso não significa que os conceitos biológicos sejam de conhecimento público, nem tampouco dos estudantes de Biologia. Para analisar o conhecimento de conceitos fundamentais de Genética, Biologia Molecular e Biologia celular apresentado por graduandos do último ano de Cursos Superiores de Ciências Biológicas é que realizamos esse trabalho de pesquisa. Iniciamos o trabalho com a seleção das questões do Exame Nacional de Cursos de Biologia (Provão) do ano de 2002 que abordavam conceitos de Genética e disciplinas correlatas, analisamos o relatório do ENC-BIO/2002 expedido pelo MEC, aplicamos questionários com as questões analisadas do ENC-BIO/2002 em 72 estudantes do último ano dos cursos de Ciências Biológicas, realizamos 33 entrevistas semi-estruturadas com estudantes do último ano dos cursos de Ciências Biológicas e, por fim, analisamos os resultados apresentados pelo relatório do MEC e das entrevistas realizadas. Concluímos que os estudantes não chegam a alcançar os objetivos que a ele são atribuídos pelo MEC, no que diz respeito à Genética e disciplinas correlatas e a maioria apresenta aprendizagem mecânica.; Biology today is the most talked about science and also the one which gets the largest media coverage. However...

Ser (animal) humano: evolucionismo e criacionismo nas concepções de alguns graduandos em ciências biológicas; The human (animal) being: evolutionism and creationism according to the conceptions of some graduating students in biological sciences.

Pagan, Acacio Alexandre
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/03/2009 Português
Relevância na Pesquisa
45.96%
Diversos estudos investigaram o espaço do ser humano no campo das Ciências Biológicas. Partindo do entendimento do currículo visível em documentos oficiais e livros didáticos, perceberam que as discussões se fixam principalmente nos conteúdos sobre o corpo. Neste trabalho, buscou-se mostrar que as Ciências Biológicas, enraizadas no paradigma evolucionista, têm apresentado novas versões sobre a origem, a natureza e a finitude humana. Pensar sobre quem somos, de onde viemos e para onde vamos, sob o enfoque evolucionista, amplia o conjunto de discursos possíveis sobre o ser humano, trazendo alternativas àqueles tradicionalmente instituídos, por exemplo, pelas religiões. O debate sobre influências desses dois campos, religião e ciência, na formação das concepções de ser humano para o professor de biologia pode ser importante motivador de reflexões, dentre outras, sobre ética e diferenças culturais. Neste sentido, o objetivo desta pesquisa foi identificar influências de tendências evolutivas e criacionistas nas concepções sobre o ser humano, a partir dessas três questões existenciais (quem somos, de onde viemos e para onde vamos), conforme manifestações de estudantes universitários de Ciências Biológicas da Universidade do Estado de Mato Grosso (UNEMAT)...

Aprendizado dos conceitos de flor e fruto e sua utilização pelos alunos de ciências biológicas do I. B. - USP; Learning concepts of flower and fruit and their use by students of biological sciences IB - USP

Pucinelli, Ricardo Henrique
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/04/2010 Português
Relevância na Pesquisa
45.91%
O sujeito ingressante no ensino superior tende a passar por um processo de adaptação da sua linguagem (senso comum) para a linguagem científica, uso restrito dos centros acadêmicos e universitários, na maioria das vezes. Desta forma, o universitário passa a conviver com duas realidades - a do "mundo prático" e a do "mundo acadêmico" (MINOGUE, 1981). O universitário, então, encontra-se diante do desafio de adequar-se às novas regras e às práticas do ensino superior. A nossa pesquisa teve como objetivos verificar como estes "sujeitos da aprendizagem" (LEVINAS, 1998) conciliam a práxis universitária com a sua formação acadêmica, sem se desvencilhar dos objetivos das Ciências - entender a natureza. Outros dois objetivos também foram delimitados, ou seja, procuramos verificar: 1º) que significados os ingressantes do curso de Ciências Biológicas da USP dão aos conceitos - flor e fruto; 2º) se esses significados sofrem "adequações" ao longo de dois anos no Instituto de Ciências Biológicas da USP. Para tanto, utilizamos-nos dos instrumentos - questionário e teste de confrontação, em três momentos distintos, a saber: no primeiro dia de aula da disciplina Flora, Fauna e Ambiente, em 2006; no primeiro dia de aula na disciplina Morfologia e Anatomia de Plantas Vasculares...

Internacionalização da produção científica em Ciencias Biologicas da UFRGS : 2000-2011

Santin, Dirce Maria
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
46.01%
O trabalho analisou, com base em indicadores bibliométricos, a internacionalização da produção científica em Ciências Biológicas da Universidade Federal do Rio Grande do Sul (UFRGS) publicada na forma de artigos no período de 2000 a 2011 em periódicos indexados no Science Citation Index da Web of Science (WoS). A internacionalização foi examinada sob três dimensões principais: difusão, colaboração e impacto internacional. Fazem parte da análise os artigos indexados em 33 categorias de assunto da WoS selecionadas para a pesquisa e que contêm pelo menos um autor vinculado à UFRGS no campo Address dos registros bibliográficos. Os 5.168 artigos analisados revelam a atividade e o crescimento significativo da produção científica no período, com prevalência de algumas áreas e de autores a elas associados. Os indicadores de difusão internacional demonstram forte preferência dos autores vinculados às Ciências Biológicas da UFRGS pelos periódicos estrangeiros, que representam 96,5% dos títulos utilizados para publicação e procedem especialmente dos EUA, da Inglaterra e da Holanda. O uso do idioma inglês foi elevado e ocorreu em 94,8% das publicações. A publicação dos artigos ocorreu em 37 países, incluindo o Brasil...

Emerging predictable features of replicated biological invasion fronts

Giometto, Andrea; Rinaldo, Andrea; Carrara, Francesco; Altermatt, Florian
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Biological dispersal is a key driver of several fundamental processes in nature, crucially controlling the distribution of species and affecting their coexistence. Despite its relevance for important ecological processes, however, the subject suffers an acknowledged lack of experimentation, and current assessments point at inherent limitation to predictability even in the simplest ecological settings. We show, by combining replicated experimentation on the spread of the ciliate Tetrahymena sp. with a theoretical approach based on stochastic differential equations, that information on local unconstrained movement and reproduction of organisms (including demographic stochasticity) allows reliable prediction of both the propagation speed and range of variability of invasion fronts over multiple generations.

Decoupling catalytic activity from biological function of the ATPase that powers lipopolysaccharide transport

Sherman, David J.; Lazarus, Michael B.; Murphy, Lea; Liu, Charles; Walker, Suzanne; Ruiz, Natividad; Kahne, Daniel
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Gram-negative bacteria contain an unusual outer membrane that prevents the entry of most currently available antibiotics. This membrane contains a complex glycolipid, LPS, on the exterior. It is not understood how such a large molecule, which can contain hundreds of sugars and six fatty acyl chains, is transported across the cell envelope from its site of synthesis in the cytoplasmic membrane to the cell surface. Using a combination of genetics, biochemistry, and structural biology, we characterized residues in the protein that powers LPS transport to gain mechanistic insight into how ATP hydrolysis is coupled to the biological function of the transporter. These tools help us understand how to design antibiotics targeting this essential pathway.

Spatially robust estimates of biological nitrogen (N) fixation imply substantial human alteration of the tropical N cycle

Sullivan, Benjamin W.; Smith, W. Kolby; Townsend, Alan R.; Nasto, Megan K.; Reed, Sasha C.; Chazdon, Robin L.; Cleveland, Cory C.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Biological nitrogen fixation (BNF) is the largest natural source of new nitrogen (N) to terrestrial ecosystems. Tropical forest ecosystems are a putative global hotspot of BNF, but direct, spatially explicit measurements in the biome are virtually nonexistent. Nonetheless, robust estimates of tropical forest BNF are critical for understanding how these important ecosystems may respond to global change and assessing human perturbations to the N cycle. Here, we introduce a spatial sampling method to assess BNF and present evidence that tropical forest BNF is much lower than previously assumed. Our results imply that humans have roughly doubled N inputs to the tropical forest biome relative to N inputs through BNF.

Realized niche shift during a global biological invasion

Tingley, Reid; Vallinoto, Marcelo; Sequeira, Fernando; Kearney, Michael R.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Species’ distributions result from dispersal and physiological constraints, interactions with other species, and ultimately, evolution. Biological invasions result from the deliberate or accidental movement of species between regions they would not reach through natural dispersal and can cause major conservation, economic, and human health issues. However, invasions also provide fascinating insights into species’ distribution limits. We investigate the invasion of the cane toad from South America to Australia by comparing the results of two modeling approaches: one considering physiological constraints and the other considering the joint influences of physiology, dispersal, and biotic interactions. Our findings demonstrate that the cane toad is limited in its native distribution by biotic interactions but, in Australia, is free to fill its climatic potential.

Expansion of the fusion stalk and its implication for biological membrane fusion

Risselada, Herre Jelger; Bubnis, Gregory; Grubmüller, Helmut
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
We focus on computing lipidic fusion pathway energetics and interpret them in a biological context. We illustrate that the progression of fast synaptic fusion may not rely on the point-like forces that are being transmitted to the membrane via the transmembrane domains of SNARE molecules. Our work bridges the many present gaps between diverse but related experiments and their interpretation, thus providing a coherent and integrative picture.

Ribonucleotide reductases reveal novel viral diversity and predict biological and ecological features of unknown marine viruses

Sakowski, Eric G.; Munsell, Erik V.; Hyatt, Mara; Kress, William; Williamson, Shannon J.; Nasko, Daniel J.; Polson, Shawn W.; Wommack, K. Eric
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Within aquatic ecosystems viruses facilitate horizontal gene transfer, biogeochemical cycling, and energy transfer by infecting and lysing microbial host cells. Despite their critical role in ecosystem function we understand little of the biological, ecological, and evolutionary features of most viruses in nature. We identify ribonucleotide reductase (RNR) genes as superior markers of viral diversity. RNR genes are distributed over a broad range of viruses. The most abundant RNR genes in marine environments are from novel groups only distantly related to known viruses. Frequency distributions of RNR clades within viral metagenome sequence libraries support predictions made by the “kill the winner” hypothesis, indicating that specialist podoviruses specifically adapted to infecting abundant heterotrophic bacterioplankton predominate within the virioplankton.

Biological evidence supports an early and complex emergence of the Isthmus of Panama

Bacon, Christine D.; Silvestro, Daniele; Jaramillo, Carlos; Smith, Brian Tilston; Chakrabarty, Prosanta; Antonelli, Alexandre
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
The formation of the Isthmus of Panama, which linked North and South America, is key to understanding the biodiversity, oceanography, atmosphere, and climate in the region. Despite its importance across multiple disciplines, the timing of formation and emergence of the Isthmus and the biological patterns it created have been controversial. Here, we analyze molecular and fossil data, including terrestrial and marine organisms, to show that biotic migrations across the Isthmus of Panama began several million years earlier than commonly assumed. An earlier evolution of the Isthmus has broad implications for the mechanisms driving global climate (e.g., Pleistocene glaciations, thermohaline circulation) as well as the rich biodiversity of the Americas.

Modular architecture in biological networks

Ramachandran, Gopal (Gopal Sebastian)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 207 p.
Português
Relevância na Pesquisa
45.92%
In the past decade, biology has been revolutionized by an explosion in the availability of data. Translating this new wealth of information into meaningful biological insights and clinical breakthroughs will require a complete overhaul both in the questions being asked, and the methodologies used to answer them. One of the largest challenges in organizing and understanding the data coming from genome sequencing, microarray experiments, and other high-throughput measurements, will be the ability to find large-scale structure in biological systems. Ideally, this would lead to a simplified representation, wherein the thousands of genes in an organism can be viewed as a much smaller number of dynamic modules working in concert to accomplish cellular functions. Toward demonstrating the importance of higher-level, modular structure in biological systems, we have performed the following analyses: 1. Using computational techniques and pre-existing protein-protein interaction (PPI) data, we have developed general tools to find and validate modular structure. We have applied these approaches to the PPI networks of yeast, fly, worm, and human.; (cont.) 2. Utilizing a modular scaffold, we have generated predictions that attempt to explain existing system-wide experiments as well as predict the function of otherwise uncharacterized proteins. 3. Following the example of comparative genomics...

Bacteriophages of Erwinia amylovora and their potential use in biological control

Gill, Jason J.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
55.73%
Forty-four bacteriophage isolates of Erwinia amy/ovora, the causal agent of fire blight, were collected from sites in and around the Niagara Region of Southern Ontario in the summer of 1998. Phages were isolated only from sites where fire blight was present. Thirty-seven of these phages were isolated from the soil surrounding infected trees, with the remainder isolated from aerial plant tissue samples. A mixture of six E. amy/ovora bacterial host strains was used to enrich field samples in order to avoid the selection bias of a single-host system. Molecular characterization of the phages with a combination of peR and restriction endonuclease digestions showed that six distinct phage types were isolated. Ten phage isolates related to the previously characterized E. amy/ovora phage PEa1 were isolated, with some divergence of molecular markers between phages isolated from different sites. The host ranges of the phages revealed that certain types were unable to efficiently lyse some E. amy/ovora strains, and that some types were able to lyse the epiphytic bacterium Pantoea agg/omerans. Biological control of E. amy/ovora by the bacteriophages was assessed in a bioassay using discs of immature pear fruit. Twenty-three phage isolates were able to significantly suppress the incidence of bacterial exudate on the pear disc surface. Quantification of the bacterial population remaining on the disc surface indicated that population reductions of up to 97% were obtainable by phage treatment...

O estágio supervisionado no curso de licenciatura em Ciências Biológicas na Universidade Federal de Goiás – Campus Goiânia; The Supervised Internship I in Biological Sciences Bachelor’s degree, at the Federal University of Goiás– Goiânia’s Campus

Souza, Leandro Nunes de
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Educação em Ciências e Matemática (PRPG); Pró-Reitoria de Pós-graduação (PRPG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Educação em Ciências e Matemática (PRPG); Pró-Reitoria de Pós-graduação (PRPG)
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
55.8%
The objective of this study is to understand how it performs Internship Required in Degree in Biological Sciencesthe Federal University of Goiás, Goiânia Campus, unveiling the different conceptions expressed in stage activities in this component. With the intention of accomplishing these purposes, we realized the need for a qualitative approach that involved, satisfactorily, all the elements of our analysis that, in fact, be understood in their complexity. From this perspective, we chose the method of case study, for which we used as a tool for data collection study document. The documents analyzed were the official documents, national and local, governing training courses for teachers of Science / Biology and Supervised, besides PPC Course investigated Plans Teaching disciplines Internship and Internship Reports. The data collected were analyzed using the technique of content analysis proposed by Bardin (2010). By analyzing the official documents we see that they they conceive stage as a moment of rapprochement with the school reality, this approach guided a link between the theory and practice, and reveal a conception of how research stage. Already the PPC treats the stage as a time of learning techniques...

Ciências da terra em cursos superiores de ciências biológicas que habilitam ao magistério de ciências naturais para o ensino fundamental; Earth science in higher education biological science courses that enable the teaching of natural science for elementary students educations

Elias Profeta Ramos de Araújo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/08/2012 Português
Relevância na Pesquisa
46.05%
Esta pesquisa teve como principal objetivo analisar o desenvolvimento de temas de Ciências da Terra em cursos de Ciências Biológicas que habilitam ao ensino de Ciências Naturais na educação básica, a fim de compreender a preparação desses acadêmicos para o ensino de Ciências da Terra, ao assumirem seus cargos de professores, além de propor ações que aprimorem essa formação. No Brasil, os cursos de Ciências Biológicas destinam-se a formar a) profissionais que exercerão atividades técnicas nas áreas biológicas e b) professores de Biologia ou Ciências Naturais. A atual preparação de professores de Ciências Naturais para o ensino fundamental de escolas da cidade de São Paulo, a partir de cursos de Ciências Biológicas de universidades do mesmo município, não se mostra apropriada em conteúdos de Ciências da Terra, conforme resultados desta pesquisa. Os currículos dos cursos de Ciências Biológicas analisados dedicam apenas 1% das suas cargas horárias à disciplina de Geologia, enquanto as provas de conhecimentos específicos, de recentes concursos de admissão de professores para a rede municipal de ensino da citada cidade, realizados pela Fundação Carlos Chagas, nos anos de 2009 e 2011, são compostas por pelo menos 10% de questões relacionadas às Ciências da Terra...

Newly discovered sister lineage sheds light on early ant evolution

Rabeling, Christian; Brown, Jeremy M.; Verhaagh, Manfred
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Ants are the world's most conspicuous and important eusocial insects and their diversity, abundance, and extreme behavioral specializations make them a model system for several disciplines within the biological sciences. Here, we report the discovery of a new ant that appears to represent the sister lineage to all extant ants (Hymenoptera: Formicidae). The phylogenetic position of this cryptic predator from the soils of the Amazon rainforest was inferred from several nuclear genes, sequenced from a single leg. Martialis heureka (gen. et sp. nov.) also constitutes the sole representative of a new, morphologically distinct subfamily of ants, the Martialinae (subfam. nov.). Our analyses have reduced the likelihood of long-branch attraction artifacts that have troubled previous phylogenetic studies of early-diverging ants and therefore solidify the emerging view that the most basal extant ant lineages are cryptic, hypogaeic foragers. On the basis of morphological and phylogenetic evidence we suggest that these specialized subterranean predators are the sole surviving representatives of a highly divergent lineage that arose near the dawn of ant diversification and have persisted in ecologically stable environments like tropical soils over great spans of time.

Photosynthetic metabolism of C3 plants shows highly cooperative regulation under changing environments: A systems biological analysis

Luo, Ruoyu; Wei, Haibin; Ye, Lin; Wang, Kankan; Chen, Fan; Luo, Lijun; Liu, Lei; Li, Yuanyuan; Crabbe, M. James C.; Jin, Li; Li, Yixue; Zhong, Yang
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
We studied the robustness of photosynthetic metabolism in the chloroplasts of C3 plants under drought stress and at high CO2 concentration conditions by using a method called Minimization of Metabolic Adjustment Dynamic Flux Balance Analysis (M_DFBA). Photosynthetic metabolism in the chloroplasts of C3 plants applies highly cooperative regulation to minimize the fluctuation of metabolite concentration profiles in the face of transient perturbations. Our work suggests that highly cooperative regulation assures the robustness of the biological system and that there is closer cooperation under perturbation conditions than under normal conditions. This results in minimizing fluctuations in the profiles of metabolite concentrations, which is the key to maintaining a system's function. Our methods help in understanding such phenomena and the mechanisms of robustness for complex metabolic networks in dynamic processes.

Low early-life social class leaves a biological residue manifested by decreased glucocorticoid and increased proinflammatory signaling

Miller, Gregory E.; Chen, Edith; Fok, Alexandra K.; Walker, Hope; Lim, Alvin; Nicholls, Erin F.; Cole, Steve; Kobor, Michael S.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
55.8%
Children reared in unfavorable socioeconomic circumstances show increased susceptibility to the chronic diseases of aging when they reach the fifth and sixth decades of life. One mechanistic hypothesis for this phenomenon suggests that social adversity in early life programs biological systems in a manner that persists across decades and thereby accentuates vulnerability to disease. Here we examine the basic tenets of this hypothesis by performing genome-wide transcriptional profiling in healthy adults who were either low or high in socioeconomic status (SES) in early life. Among subjects with low early-life SES, there was significant up-regulation of genes bearing response elements for the CREB/ATF family of transcription factors that conveys adrenergic signals to leukocytes, and significant down-regulation of genes with response elements for the glucocorticoid receptor, which regulates the secretion of cortisol and transduces its antiinflammatory actions in the immune system. Subjects from low-SES backgrounds also showed increased output of cortisol in daily life, heightened expression of transcripts bearing response elements for NF-κB, and greater stimulated production of the proinflammatory cytokine interleukin 6. These disparities were independent of subjects' current SES...

Kinetochore reproduction in animal evolution: Cell biological explanation of karyotypic fission theory

Kolnicki, Robin L.
Fonte: The National Academy of Sciences Publicador: The National Academy of Sciences
Tipo: Artigo de Revista Científica
Publicado em 15/08/2000 Português
Relevância na Pesquisa
55.8%
Karyotypic fission theory of Todd offers an explanation for the diverse range of diploid numbers of many mammalian taxa. Theoretically, a full complement of acrocentric chromosomes can be introduced into a population by chromosomal fission. Subsequent inheritance of ancestral chromosomes and paired fission derivatives potentially generates a diploid range from the ancestral condition to double its number of chromosomes. Although it is undisputed that both chromosomal fission and fusion (“Robertsonian rearrangements”) have significantly contributed to karyological diversity, it is generally assumed that independent events, the fission of single chromosomes or the fusion of two chromosomes, are the sources of such change. The karyotypic fission idea by contrast posits that all mediocentric chromosomes simultaneously fission. Here I propose a specific cell biological mechanism for Todd's karyotypic fission concept, “kinetochore reproduction theory,” where a complete set of dicentric chromatids is synthesized during gametogenesis, and kinetochore protein dephosphorylation regulates dicentric chromatid segregation. Three postulates of kinetochore reproduction theory are: (i) breakage of dicentric chromosomes between centromere pairs forms acrocentric derivatives...

Biological soil crusts accelerate the nitrogen cycle through large NO and HONO emissions in drylands

Weber, Bettina; Wu, Dianming; Tamm, Alexandra; Ruckteschler, Nina; Rodríguez-Caballero, Emilio; Steinkamp, Jörg; Meusel, Hannah; Elbert, Wolfgang; Behrendt, Thomas; Sörgel, Matthias; Cheng, Yafang; Crutzen, Paul J.; Su, Hang; Pöschl, Ulrich
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Text
Português
Relevância na Pesquisa
55.8%
Biological soil crusts (biocrusts), occurring on ground surfaces in drylands throughout the world, are among the oldest life forms consisting of cyanobacteria, lichens, mosses, and algae plus heterotrophic organisms in varying proportions. They prevent soil erosion and nurture ecosystems by fixing carbon and nitrogen from the atmosphere. Here, we show that the fixed nitrogen is processed within the biocrusts, and during this metabolic activity, nitrogen oxide and nitrous acid are released to the atmosphere. Both of these gases are highly relevant, as they influence the radical formation and oxidizing capacity of the lower atmosphere, also interacting with climate change. In drylands, biocrusts appear to play a key role both in nitrogen fixation and the release of atmospheric reactive nitrogen.