Search results for "Extreme environment"

The influence of thermal extremes on coral reef fish behaviour in the Arabian/Persian Gulf

2019

Despite increasing environmental variability within marine ecosystems, little is known about how coral reef fish species will cope with future climate scenarios. The Arabian/Persian Gulf is an extreme environment, providing an opportunity to study fish behaviour on reefs with seasonal temperature ranges which include both values above the mortality threshold of Indo-Pacific reef fish, and values below the optimum temperature for growth. Summer temperatures in the Gulf are comparable to those predicted for the tropical ocean by 2090–2099. Using field observations in winter, spring and summer, and laboratory experiments, we examined the foraging activity, distance from refugia and resting tim…

The tougher the environment, the harder the adaptation? A psychological point of view in extreme situations

2021

IF: 2.8 (Q1); International audience; Grounded within a multidimensional and multilevel approach, the aim of this study was to investigate the time course of Psychological Adaptation Process (PAP) dimensions (social, emotional, occupational, and physical) during one-year polar winter-overs in Subantarctic and Antarctic stations. The effects of perceived control (PC) at the start of polar winter on the dynamics of the PAP dimensions were also examined. The present findings clarify some changes in PAP in extreme environments: (a) The dimensions of psychological adaptation evolved differently as a function of environmental conditions; and (b) PC influenced the trajectories of PAP dimensions. T…

Ubiquitous giants: a plethora of giant viruses found in Brazil and Antarctica

2018

Background Since the discovery of giant viruses infecting amoebae in 2003, many dogmas of virology have been revised and the search for these viruses has been intensified. Over the last few years, several new groups of these viruses have been discovered in various types of samples and environments.In this work, we describe the isolation of 68 giant viruses of amoeba obtained from environmental samples from Brazil and Antarctica. Methods Isolated viruses were identified by hemacolor staining, PCR assays and electron microscopy (scanning and/or transmission). Results A total of 64 viruses belonging to the Mimiviridae family were isolated (26 from lineage A, 13 from lineage B, 2 from lineage C…

Biodiversity, evolution and adaptation of fungi in exstreme environments

2013

Fungi play irreplaceable roles for ecosystem functioning. They may adopt different life styles, for example saprotrophs, symbionts or parasites: some species are cosmopolitan with a wide distribution and others, thanks to they ecological plasticity, may adapt to harsh environments precluded to most of life forms. In stressing conditions, their role is even more crucial for the recycling of organic matter or favouring nutrients uptake. When the conditions become really extreme and competion is low, fungi focus on extremotollerance and evolve peculiar competences to exploit natural or xenobiotic resources in the particular constraints imposed by the environment. This paper focuses on three di…

Social, Occupational, and Cultural Adaptation During a 12-Month Wintering in Antarctica.

2016

Background and methods Life in isolated and confined environments (ICEs) is subject to important constraints which can generate psychosociologically impaired outcomes. This study investigated psychological, social, occupational, and cultural variables which are among the most important determinants in adaptation to a one-year wintering in Antarctica for 13 international subjects. Results Our findings confirm and give further insight into the role of social (Cohesiveness, Social Support) and occupational (Implementation/Preparedness, Counterproductive Activity, Decision Latitude, and Psychological Job Demands) dimensions of adaptation to ICEs. Relationships between various social and occupat…

Technology for plant food support in Antarctica

2011

Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 cell surface hydrophobicity and survival of the cells under adverse environmental condi…

2012

Abstract Changes in the cell surface hydrophobicity (CSH) of probiotic bacteria Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and the survival of these cells were examined in response to varied cultivation conditions and adverse environmental conditions. An inverse linear relationship (P < 0.01) was detected between the CSH of intact L. acidophilus La5 and B. lactis Bb12 and survival of cells subjected to subsequent freezing/thawing, long-term storage or exposure to mineral and bile acids. The observed relationships were supported by significant correlations between the CSH and changes in composition of the cell envelopes (proteins, lipids and carbohydrates) of L. aci…

Mars-105 study : Time-courses and relationships between coping, defense mechanisms, emotions and depression

2013

International audience; This study investigated the time-courses and the relationships between coping, defense mechanisms, emotions and depression considered as key factors in adaptation to ICE (Isolated and Confined Extreme) environments. During the space simulation, the Mars-105 experiment, positive emotion decreased significantly and significant positive correlations were found between mature defenses and both positive emotions and Task-Oriented Coping (TOC), as well as between Disengagement-Oriented Coping (DOC) and symptoms of depression. These findings show the impact of space simulation on affective states and the relations of defense to both coping and emotion, which underline the r…

Phytoplankton in extreme environments: importance and consequences of habitat permanency

2020

AbstractThere is hardly any sunshine exposed surface on this Earth, be it water or terrain, which would not support some biota. Still, many habitats offer harsh conditions requiring specialized physiological adaptations to survive. These environments are referred to as extremes; often inhabited by extremophilic organisms. In this review, characteristic species and assemblage properties of phytoplankton inhabiting extreme environments (especially lakes and pools where planktic life is potentially possible and independently of their origin) in terms of alkalinity, acidity, DOC, salinity, temperature, light and mixing regime will be outlined. Lakes characterized by more than a single extreme a…

Monitoring seasonal changes in microbial populations of spruce forest soil of the Northern Temperate Zone

2012

Soil microbial populations in the Northern Temperate Zone have been poorly studied in comparison with extreme environments. The aim of the work was to study the seasonal changes in the microbial populations of spruce forest soil of the Northern Temperate Zone using classical methods of microbiology and molecular biology. Upper horizons in two Picea abies stands on sod- podzolic and illuvial humus podzol soil were analysed. Sampling was done monthly over a period of twelve months (May 2009-April 2010). Microbial communities in both experimental plots showed different responses to the analysed environmental factors. In the sod-podzolic soil only the fungal DNA amount was significantly higher …