LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 3 of total 3

Search options

  1. Article ; Online: Extreme precipitation events and geomorphic adjustments in the riverscape: A case study in Southern Brazil

    Pinto, Fábio Maciel / Schuch, Fernanda Simoni / Brentano, Débora Monteiro

    Resources, Environment and Sustainability. 2023 May 22, p.100124-

    2023  , Page(s) 100124–

    Abstract: Extreme precipitation events can cause geomorphic adjustments in the riverscapes. As a result of the increase in severity and frequency of these events in climate change scenarios, riverscapes may become more sensitive to the geoforms sculpting processes. ...

    Abstract Extreme precipitation events can cause geomorphic adjustments in the riverscapes. As a result of the increase in severity and frequency of these events in climate change scenarios, riverscapes may become more sensitive to the geoforms sculpting processes. Consequently, communities in the river valleys may be adversely affected, worsening socio-environmental problems arising from these places' occupation. This work investigates the relationship between events classified as heavy rainfall and persistent rainfall and geomorphic adjustments in the riverscape. A section of the Itapocu River in southern Brazil between latitudes 26°25'S and 26°32'S was used as a case study. Extreme events recorded in pluviometers' historical series located around the study area were selected and characterized. These events occurred between 01/30/2019 and 04/15/2019; 11/15/2019 and 12/30/2019; 02/23/2021 and 03/10/2021. The geomorphic adjustments were identified by selecting Sentinel 2 orbital imagery. The satellite images were applied in the river valley geoforms vectorization and correlation among transverse and longitudinal sections to the river valley. The analysis of fluvial sensitivity went through the adjustments' significance evaluation by the Wilcoxon Signed Rank Test. The results indicated that the river presented adjustments related to extreme precipitation events. These adjustments were identified as channel migration, channel expansion, channel narrowing, river bar expansion, and river bar narrowing. However, only channel migration, channel expansion, and channel narrowing were significant. In 2019, 82.03% of the river was significantly affected by the events, while in 2020 and 2021, events impacted 57.67% and 64.72% of the river, respectively.
    Keywords case studies ; climate change ; environment ; occupations ; rain ; river valleys ; rivers ; satellites ; Brazil ; Climate changes ; Geomorphometry ; Fluvial system ; Landscape geomorphology ; Remote sensing ; Catchment
    Language English
    Dates of publication 2023-0522
    Publishing place Elsevier B.V.
    Document type Article ; Online
    Note Pre-press version ; Use and reproduction
    ISSN 2666-9161
    DOI 10.1016/j.resenv.2023.100124
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  2. Article ; Online: Abiotic variables affect STX concentration in a meso-oligotrophic subtropical coastal lake dominated by Cylindrospermopsis raciborskii (Cyanophyceae).

    Brentano, Débora Monteiro / Giehl, Eduardo L Hettwer / Petrucio, Maurício Mello

    Harmful algae

    2016  Volume 56, Page(s) 22–28

    Abstract: The cyanobacterium Cylindrospermopsis raciborskii is capable of producing toxins including saxitoxin (STX). Few studies have verified the influence of environmental variables on the production of STX and most have only been studied in the laboratory. The ...

    Abstract The cyanobacterium Cylindrospermopsis raciborskii is capable of producing toxins including saxitoxin (STX). Few studies have verified the influence of environmental variables on the production of STX and most have only been studied in the laboratory. The goal of this work was to identify the abiotic variables related to STX concentration in situ. The relationship among STX concentration and the physical variables, nutrients and chlorophyll-a (chl-a) concentration was examined in a meso-oligotrophic subtropical coastal lake dominated by C. raciborskii. A generalized linear model was developed, incorporating all variables measured monthly over a 45-month monitoring period. Conductivity and dissolved inorganic nitrogen (DIN) concentration provided the greatest explanatory power for STX concentration in situ. Previous studies suggested that C. raciborskii cells exposed to stress associated with higher ionic concentrations appear to activate the biosynthesis of STX suggesting that STX can elicit changes cell permeability and may contribute to the homeostasis of this organism. An increase of DIN concentration results in a higher concentration of STX which may be related to a reduced metabolic demand, since the uptake of inorganic nitrogen requires less energy than N
    MeSH term(s) Cylindrospermopsis/metabolism ; Environmental Monitoring ; Lakes/chemistry ; Nitrogen/metabolism ; Saxitoxin/analysis ; Saxitoxin/metabolism
    Chemical Substances Saxitoxin (35523-89-8) ; Nitrogen (N762921K75)
    Language English
    Publishing date 2016-05-17
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2091119-1
    ISSN 1878-1470 ; 1568-9883
    ISSN (online) 1878-1470
    ISSN 1568-9883
    DOI 10.1016/j.hal.2016.03.017
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: Abiotic variables affect STX concentration in a meso-oligotrophic subtropical coastal lake dominated by Cylindrospermopsis raciborskii (Cyanophyceae)

    Brentano, Débora Monteiro / Eduardo L. Hettwer Giehl / Maurício Mello Petrucio

    Harmful algae. 2016 June, v. 56

    2016  

    Abstract: The cyanobacterium Cylindrospermopsis raciborskii is capable of producing toxins including saxitoxin (STX). Few studies have verified the influence of environmental variables on the production of STX and most have only been studied in the laboratory. The ...

    Abstract The cyanobacterium Cylindrospermopsis raciborskii is capable of producing toxins including saxitoxin (STX). Few studies have verified the influence of environmental variables on the production of STX and most have only been studied in the laboratory. The goal of this work was to identify the abiotic variables related to STX concentration in situ. The relationship among STX concentration and the physical variables, nutrients and chlorophyll-a (chl-a) concentration was examined in a meso-oligotrophic subtropical coastal lake dominated by C. raciborskii. A generalized linear model was developed, incorporating all variables measured monthly over a 45-month monitoring period. Conductivity and dissolved inorganic nitrogen (DIN) concentration provided the greatest explanatory power for STX concentration in situ. Previous studies suggested that C. raciborskii cells exposed to stress associated with higher ionic concentrations appear to activate the biosynthesis of STX suggesting that STX can elicit changes cell permeability and may contribute to the homeostasis of this organism. An increase of DIN concentration results in a higher concentration of STX which may be related to a reduced metabolic demand, since the uptake of inorganic nitrogen requires less energy than N2-fixation. Thus, increased DIN can favor the growth of C. raciborskii population or improve cellular homeostasis, both potentially increasing STX concentration in the aquatic system, which was observed through a delayed response pattern. The developed model, while providing only a moderate predictive power, can assist in the understanding of the environmental variables associated with increases in STX concentration, and in monitoring and minimizing the risks of toxic blooms.
    Keywords algae ; biosynthesis ; chlorophyll ; Cylindrospermopsis raciborskii ; dissolved inorganic nitrogen ; energy ; environmental factors ; homeostasis ; lakes ; linear models ; monitoring ; nitrogen ; nutrients ; permeability ; risk ; toxicity ; toxins
    Language English
    Dates of publication 2016-06
    Size p. 22-28.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 2091119-1
    ISSN 1878-1470 ; 1568-9883
    ISSN (online) 1878-1470
    ISSN 1568-9883
    DOI 10.1016/j.hal.2016.03.017
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

To top