75 research outputs found
Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores
A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació
Bioluminescence : a proxy of biological activity in the deep sea? Study in the laboratory and in situ of bioluminescence linked to the environmental variables.
La bioluminescence est l’émission de lumière par des organismes vivants. En milieu bathypélagique, où l’absence de lumière est une caractéristique majeure, ce phénomène semble avoir un rôle écologique primordial dans les interactions biologiques ainsi que dans le cycle du carbone. Ce travail cherche à déterminer si la bioluminescence peut être définie comme un proxy de l’activité biologique en milieu profond. Cette étude multidisciplinaire développe à la fois une approche in situ et en laboratoire. Le télescope ANTARES, immergé en Méditerranée, à 2475 m de profondeur, a joué le rôle d’un observatoire océanographique enregistrant la bioluminescence ainsi que les variables environnementales à haute fréquence. L’analyse de ces séries temporelles, non-linéaires et non-stationnaires a permis de mettre en évidence deux périodes de forte activité de bioluminescence en 2009 et 2010. Ces évènements ont été expliqués par des phénomènes de convection dans le Golfe du Lion, impactant indirectement la bioluminescence enre- gistrée sur ANTARES. En laboratoire, la bioluminescence bactérienne a été décrite sur une souche modèle piezophile, isolée au cours d’un évènement de forte bioluminescence. La pression hydrostatique liée à la profondeur in situ (22 MPa) induit une plus forte bioluminescence qu’à pression atmosphérique (0.1 MPa). Enfin, le suivi des communautés procaryotiques profondes a été réalisé, sur le site ANTARES, au cours de l’année 2011. Ce suivi a montré la présence de 0.1 à 1% de bactéries bioluminescentes dans une période enregistrant une faible activité de bioluminescence. Ces cellules ont été définies comme majoritairement actives.Bioluminescence is the emission of light by living organisms. In the bathypelagic waters, where darkness is one of the main characteristic, this phenomenon seems to play a major role for biological interactions and in the carbon cycle. This work aims to determine if bioluminescence can be considered as a proxy of biological activity in the deep sea. This multidisciplinary study develops both in situ and laboratory approaches. The ANTARES telescope immersed in the Mediterranean Sea at 2,475 m depth has been used as an oceanographic observatory recording bioluminescence as well as environmen- tal variables at high frequency. This time series analysis, defined as non linear and non stationary, highlighted two periods of high bioluminescence intensity in 2009 and 2010. These events have been explained by convection phenomena in the Gulf of Lion, indi- rectly impacting the bioluminescence sampled at this station. In the laboratory, bacterial bioluminescence has been described using a piezophilic bacterial model isolated during a high-bioluminescence-intensity event. Hydrostatic pressure linked to the in situ depth (22 MPa) induces a higher bioluminescence activity than under atmospheric pressure (0.1 MPa). Then, the survey of the deep prokaryotic communities has been done at the AN- TARES station, over the year 2011. This survey shows the presence of about 0.1 to 1% of bioluminescent bacteria even during a low-bioluminescence-activity period. These cells were mainly actives
How to analyse bioluminescence time series from in situ observatories? Example from high frequency records and real time data at the ANTARES site
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Reviews and syntheses: Bacterial bioluminescence – ecology and impact in the biological carbon pump
International audienceAround 30 species of marine bacteria can emit light, a critical characteristic in the oceanic environment is mostly deprived of sunlight. In this article, we first review current knowledge on bioluminescent bacteria symbiosis in light organs. Then, focusing on gut-associated bacteria, we highlight that recent works, based on omics methods, confirm previous claims about the prominence of bioluminescent bacterial species in fish guts. Such host–symbiont relationships are relatively well-established and represent important knowledge in the bioluminescence field. However, the consequences of bioluminescent bacteria continuously released from light organs and through the digestive tracts to the seawater have been barely taken into account at the ecological and biogeochemical level. For too long neglected, we propose considering the role of bioluminescent bacteria and reconsidering the biological carbon pump, taking into account the bioluminescence effect (“bioluminescence shunt hypothesis”). Indeed, it has been shown that marine snow and fecal pellets are often luminous due to microbial colonization, which makes them a visual target. These luminous particles seem preferentially consumed by organisms of higher trophic levels in comparison to nonluminous ones. As a consequence, the sinking rate of consumed particles could be either increased (due to repackaging) or reduced (due to sloppy feeding or coprophagy/coprorhexy), which can imply a major impact on global biological carbon fluxes. Finally, we propose a strategy, at a worldwide scale, relying on recently developed instrumentation and methodological tools to quantify the impact of bioluminescent bacteria in the biological carbon pump
Bioluminescence in an Undescribed Species of Carnivorous Sponge (Cladorhizidae) From the Deep Sea
International audienceOne dominant ecological trait in the dimly-lit deep-sea is the ability of organisms to emit bioluminescence. Despite its many ecological roles in deep-sea ecosystems, the presence of inherent bioluminescence in marine sponges has been debated for more than a century. This work reports repeated observations of luminescence from six individuals of an undescribed carnivorous sponge species (Cladorhizidae) sampled near 4,000 m depth off Monterey Bay (CA, United States). These are the first fully documented records of bioluminescence in the phylum Porifera. Videos and photographs of the sponges' bioluminescence were recorded on board after collection and in vitro bioluminescence assays indicate that the bioluminescence system is a coelenterazine-based luciferase. Coelenterazine luciferin is already described in various organisms such as cnidarians, chaetognaths, copepods, cephalopods, ctenophores, ostracods, and some mysid or decapod shrimps. Based on these observations we discuss new ecological hypotheses of functional traits such as bioluminescence and carnivory in deep sea organisms
Distribution and quantification of bioluminescence as an ecological trait in the deep sea benthos
International audienceBioluminescence is a prominent functional trait used for visual communication. A recent quantification showed that in pelagic ecosystems more than 75% of individual macro-planktonic organisms are categorized as able to emit light. In benthic ecosystems, only a few censuses have been done, and were based on a limited number of observations. In this study, our dataset is based on observations from remotely operated vehicle (ROV) dives conducted from 1991–2016, spanning 0–3,972 m depth. Data were collected in the greater Monterey Bay area in central California, USA and include 369,326 pelagic and 154,275 epibenthic observations at Davidson Seamount, Guide Seamount, Sur Ridge and Monterey Bay. Because direct observation of in situ bioluminescence remains a technical challenge, taxa from ROV observations were categorized based on knowledge gained from the literature to assess bioluminescence status. We found that between 30–41% of the individual observed benthic organisms were categorized as capable of emitting light, with a strong difference between benthic and pelagic ecosystems. We conclude that overall variability in the distribution of bioluminescent organisms is related to the major differences between benthic and pelagic habitats in the deep ocean. This study may serve as the basis of future investigations linking the optical properties of various habitats and the variability of bioluminescent organism distributions
Using fluorescence and bioluminescence sensors to characterize auto- and heterotrophic plankton communities
International audienceHigh-resolution autonomous sensors routinely measure physical (temperature, salinity), chemical (oxygen, nutrients) and biological (fluorescence) parameters. However, while fluorescence provides a proxy for phyto-plankton, heterotrophic populations remain challenging to monitor in real-time and at high resolution. Bathyphotometers, sensors which measure the light emitted by bioluminescent organisms when mechanically stimulated, provide the capability to identify bioluminescent dinoflagellates and zooplankton. In the coastal ocean, highly abundant dinoflagellates emitting low-intensity flashes generate a background bioluminescence signal, while rarer zooplankton emit bright flashes that can be individually resolved by high-frequency sensors. Bathyphotometers were deployed from ships and onboard autonomous underwater vehicles (AUVs) during three field campaigns in Monterey Bay, California. Ship-based in situ water samples were simultaneously collected and the plankton communities characterized. Plankton concentrations were matched with concurrent datasets of fluorescence and bioluminescence to develop proxies for autotrophic and heterotrophic dinoflagellates, other phytoplankton such as diatoms, copepods, larvaceans (appendicularians), and small jellies. The method extracts the bioluminescence background as a proxy for dinoflagellates, and exploits differences in bioluminescence flash intensity between several types of zooplankton to identify larvaceans, copepods and small jellies. Fluorescence is used to discriminate between autotrophic and heterotrophic dinoflagellates, and to identify other autotrophic plankton. Concurrent fluorometers and bathyphotometers onboard AUVs can thus provide a novel view of plankton diversity and phytoplankton/zooplankton interactions in the sea
Bacteria as part of bioluminescence emission at the deep ANTARES station (North-Western Mediterranean Sea) during a one-year survey
Bioluminescent bacteria have been studied during a one-year survey in 2011 at the deep ANTARES site (Northwestern Mediterranean Sea, 2000 m depth). The neutrino underwater telescope ANTARES, located at this station, has been used to record the bioluminescence at the same depth. Together with these data, environmental variables (potential temperature, salinity, nutrients, dissolved organic carbon and oxygen) have been characterized in water samples. The year 2011 was characterized by relatively stable conditions, as revealed by minor variability in the monitored oceanographic variables, by low bioluminescence and low current speed. This suggests weak eukaryote participation and mainly non-stimulated light emission. Hence, no processes of dense water have affected the ANTARES station during this survey. Abundance of bioluminescent bacteria belonging to Photobacterium genus, measured by qPCR of the luxF gene, ranged from 1.4 x 10(2) to 7.2 x 10(2) genes mL(-1). Their effective activity was confirmed through mRNA luxF quantification. Our results reveal that bioluminescent bacteria appeared more active than the total counterpart of bacteria, suggesting an ecological benefit of this feature such as favoring interaction with macro-organisms. Moreover, these results show that part of the bioluminescence, recorded at 2000 m depth over one year, could be due to bioluminescent bacteria in stable hydrological conditions. (C) 2016 Elsevier Ltd. All rights reserved
Functional trait-based approaches as a common framework for freshwater and marine ecologists
International audienc
Functional trait-based approaches as a common framework for freshwater and marine ecologists
International audienc
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