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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The role of bacteria and fungi in the biodegradation of the phenoxyalkanoic acid herbicides

Marriott, Martin William January 1997 (has links)
No description available.
2

Fungos ingoldianos em algumas ?reas do semi?rido brasileiro

Fiuza, Patricia Oliveira 25 March 2013 (has links)
Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-08-07T22:20:38Z No. of bitstreams: 1 Patr?cia Oliveira Fiuza_DISSERTA??O.pdf: 30896151 bytes, checksum: b11de629f19a7cd5583ce2b2f1afbd36 (MD5) / Made available in DSpace on 2015-08-07T22:20:38Z (GMT). No. of bitstreams: 1 Patr?cia Oliveira Fiuza_DISSERTA??O.pdf: 30896151 bytes, checksum: b11de629f19a7cd5583ce2b2f1afbd36 (MD5) Previous issue date: 2013-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Ingoldian fungi are aquatic hyphomycetes that presents conidia sigmoid or branch and occur in lotic and lentic environment, being easily found in foam of water bodies. Aiming to contribute to the knowledge of the biodiversity of Ingoldian fungi in semiarid region, was conducted an inventory in water bodies of areas of extreme biological importance of the Brazilian semiarid. In a single expedition, samples of foam and submerged leaves were collected in water bodies of four localities in semiarid region (Brejo Paraibano-PB, Serra da Jib?ia-BA, Chapada do Araripe and Serra de Ibiapaba-CE). The samples of foam were collected and packaged in plastic bottles of 250 mL and the submerged leaves were packaged in plastic bags. In ?Laborat?rio de Micologia?(LAMIC), the foam was homogenized and 200 ?L of each sample were transferred to 30 slides, which were exposed at room temperature to evaporation. After evaporation, was addition of one drop of lactic acid and sealed with nail polish. Samples of submerged leaves were subjected to the technique of washing in flowing water and cut into pieces of 1 cm?, that were placed in petri dishes containing distilled sterile water for observation of fungi. The bottles and slides were deposited in the ?Herb?rio da Universidade Estadual de Feira de Santana? (HUEFS). The pure cultures were deposited in the ?Cole??o de Cultura de Micro-organismos da Bahia? (CCMB). The first chapter presents all 27 taxa of Ingoldian fungi found in the study, 23 of these taxa present description, geographic distribution, taxonomic comments and illustration; 22 are new records: american continent (3), Neotropics (1), South America (3), Brazil (5), Brazilian semiarid region (7), Cear? (2) and Para?ba (1). The second chapter shows all species of the genus Campylospora with descriptions, comments, geographical distribution, a key to the genus and illustrations. The water body with the highest number of taxa of Ingoldian fungi was the river Miss?o velha. / Os fungos ingoldianos s?o hifomicetos aqu?ticos que apresentam con?dios sigmoides ou ramificados e ocorrem em ambientes l?ticos e l?nticos, sendo encontrados facilmente nas espumas de corpos d??gua. Visando contribuir com o conhecimento da biodiversidade de fungos ingoldianos na regi?o semi?rida foi realizado um invent?rio em corpos d??gua de ?reas de extrema import?ncia biol?gica do semi?rido brasileiro. Em uma expedi??o, amostras de espuma e folhas submersas foram coletadas em corpos d??gua de quatro localidades na regi?o semi?rida (Brejo Paraibano-PB, Serra da Jib?ia-BA, Chapada do Araripe e Serra de Ibiapaba-CE). As amostras de espuma foram coletadas e acondicionadas em frascos pl?sticos de 250 mL e as amostras de folhas submersas foram acondicionadas em sacos pl?sticos. No Laborat?rio de Micologia (LAMIC), a espuma foi homogeneizada e 200 ?L de cada amostra foram transferidos para 30 l?minas, as quais ficaram expostas ? temperatura ambiente para evapora??o. Ap?s a evapora??o, foi adicionada uma gota de ?cido l?ctico e vedada com esmalte. Amostras de folhas submersas foram submetidas ? t?cnica de lavagem em ?gua corrente e cortadas em peda?os de 1 cm?, os quais foram colocados em placas de Petri com ?gua destilada esterilizada para observa??o dos fungos. Os frascos e l?minas foram depositados no Herb?rio da Universidade Estadual de Feira de Santana (HUEFS). As culturas puras foram depositadas na Cole??o de Cultura de Microrganismos da Bahia (CCMB). O primeiro cap?tulo apresenta todos os 27 t?xons de fungos ingoldianos encontrados no estudo, 23 destes t?xons apresentam descri??o, distribui??o geogr?fica, coment?rios taxon?micos e ilustra??o; 22 representam novos registros: continente americano (3), Neotr?pico (1), Am?rica do Sul (3), Brasil (5), regi?o semi?rida brasileira (7), Cear? (2), Para?ba (1). O segundo cap?tulo apresenta todas as esp?cies do g?nero Campylospora, com descri??es, coment?rios taxon?micos, distribui??o geogr?fica, chave taxon?mica para o g?nero e ilustra??es. O corpo d? ?gua que apresentou o maior n?mero de t?xons de fungos ingoldianos foi o rio Miss?o Velha.
3

Anthropogenic impacts and restoration of boreal spring ecosystems

Lehosmaa, K. (Kaisa) 24 April 2018 (has links)
Abstract Human activities have increasingly altered freshwater ecosystems. Land use is a major driver of habitat loss and land use-related input of nutrients and other pollutants from agriculture, forestry and urbanization have deteriorated water quality. Freshwater research has mainly focused on lakes and streams while the effects of anthropogenic stressors on groundwater-dependent ecosystems (GDEs) are poorly known. Likewise, the effectiveness of ecological restoration in mitigating human disturbance in GDEs remains understudied. In this thesis, I studied the effects of two main anthropogenic stressors – land drainage and groundwater contamination – on boreal spring ecosystems and evaluated the recovery of spring biodiversity and ecosystem functioning after habitat restoration. I applied several structural (macroinvertebrates, bryophytes, leaf-decomposing fungi and groundwater bacteria) and functional (organic matter decomposition and primary productivity) measures to provide a comprehensive insight into these issues. Both stressors modified spring ecosystems. Land drainage reduced the key ecosystem processes. Long-term monitoring of drainage-impacted springs showed a marked biodiversity loss and change of spring-dwelling bryophytes, and no signs of recovery were observed after about 20 years since the intial land drainage. Groundwater contamination, indicated by elevated nitrate and chloride concentrations, altered the structure of spring biota, reduced their taxonomic diversity and suppressed primary productivity in the most severely contaminated springs. Spring restoration improved habitat quality by reducing drainage-induced inflow of surface water, thus re-establishing groundwater-dominated hydrological conditions. Restoration increased abundance of habitat-specialist bryophytes and shifted macroinvertebrate composition towards natural conditions, despite the restoration actions being fairly recent. Anthropogenic activities can thus cause severe structural and functional degradation of spring ecosystems, and their self-recovery potential from these stressors seems low. Habitat restoration bears great promise as a cost-effective approach to mitigate drainage-induced impacts on spring ecosystems, but protection and co-management of groundwater resources are urgently needed to secure the role of springs as biodiversity hotspots in the boreal forest landscape. / Tiivistelmä Ihmistoiminta muuttaa yhä enemmän vesiekosysteemejä. Maankäyttö on johtanut elinympäristöjen häviämiseen, ja siihen liittyvä ravinne- ja haitta-ainekuormitus maa- ja metsätaloudesta sekä kaupunkiympäristöistä on merkittävästi huonontanut veden laatua johtaen maailmanlaajuiseen vesiluonnon monimuotoisuuden heikentymiseen. Vesiekosysteemien tutkimus on keskittynyt pääasiassa järvi- ja jokiympäristöihin, kun ihmistoiminnan vaikutukset pohjavesiriippuvaisiin ekosysteemeihin tunnetaan edelleen huonosti. Samoin kunnostusten merkitys pohjavesiriippuvaisten ekosysteemien tilan parantamiseksi on selvittämättä. Väitöskirjassani tarkastelin kahden keskeisen ihmistoiminnan – metsäojituksen ja pohjaveden laadun heikkenemisen – vaikutuksia lähde-ekosysteemeihin sekä arvioin elinympäristökunnostusten vaikutuksia niiden rakenteeseen ja toimintaan. Sovelsin työssäni rakenteellisia (pohjaeläimet, sammalet, lehtikariketta hajottavat sienet ja pohjavesibakteerit) ja toiminnallisia (eloperäisen aineksen hajoaminen ja perustuotanto) mittareita tuottamaan kattavan käsityksen tutkimuskysymyksiini. Sekä metsäojitukset että pohjaveden laadun heikkeneminen aiheuttavat muutoksia lähteiden rakenteessa ja toiminnassa. Metsäojitukset hidastavat keskeisiä ekosysteemitoimintoja ja johtavat lähdesammallajiston muutokseen ja monimuotoisuuden taantumiseen. Pohjaveden pilaantuminen, jota työssä ilmennettiin kohonneilla nitraatti- ja kloridipitoisuuksilla, heikentää lähdelajiston monimuotoisuutta, muuttaa lajikoostumusta ja johtaa perustuotannon laskuun voimakkaimmin kuormitetuissa lähteissä. Kunnostus parantaa lähde-elinympäristön laatua vähentämällä metsäojien aiheuttamaa pintavesivaikutusta palauttaen pohjavesivaltaisen hydrologisen tilan. Lähdekunnostusten myötä lähdesammaleet runsastuvat ja pohjaeläinyhteisön rakenne palautuu luonnontilaisten lähteiden kaltaiseksi, vaikka kunnostuksista on kulunut vasta muutamia vuosia. Väitöskirjan tulokset osoittavat, että ihmisen toiminta voi aiheuttaa muutoksia lähde-ekosysteemien rakenteessa ja toiminnassa ja lähteiden luontainen palautuminen häiriöstä on hidasta. Lähde-elinympäristöjen kunnostus vaikuttaa lupaavalta suojelutoimenpiteeltä metsäojitusten vaikutusten vähentämisessä, mutta lähteiden säilyttäminen monimuotoisena ja suojelullisesti arvokkaana luontotyyppinä edellyttää pohjavesivarojen hallinnan ja tilan suojelun tehostamista.

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