WorldWideScience

Sample records for stressors affecting ecosystem

  1. Southern Nevada ecosystem stressors [Chapter 2

    Science.gov (United States)

    Burton K. Pendleton; Jeanne C. Chambers; Mathew L. Brooks; Steven M. Ostoja

    2013-01-01

    Southern Nevada ecosystems and their associated resources are subject to a number of global and regional/local stressors that are affecting the sustainability of the region. Global stressors include elevated carbon dioxide (CO2) concentrations and associated changes in temperature and precipitation patterns and amounts, solar radiation, and nutrient cycles (Smith and...

  2. Ecological concerns following Superstorm Sandy: stressor level and recreational activity levels affect perceptions of ecosystem.

    Science.gov (United States)

    Burger, Joanna

    2015-06-01

    Coastal habitats are vulnerable to storms, and with increasing urbanization, sea level rise, and storm frequency, some urban populations are at risk. This study examined perceptions of respondents in coastal and central New Jersey to Superstorm Sandy , including: 1) concerns about ecological resources and effects (open-ended question), 2) information sources for ecology of the coast (open-ended), and 3) ratings of a list of ecological services as a function of demographics, location (coastal, central Jersey), stressor level (power outages, high winds, flooding) and recreational rates. "Wildlife" and "fish" were the ecological concerns mentioned most often, while beaches and dunes were most often mentioned for environmental concerns. Television, radio, and web/internet were sources trusted for ecological information. The data indicate 1) stressor level was a better predictor of ratings of ecological services than geographical location, but days engaged in recreation contributed the most to variations in ratings, 2) ecological services were rated the highest by respondents with the highest stressor levels, and by those from the coast, compared to others, 3) Caucasians rated ecological services higher than all others, and 4) recreational rates were highest for coastal respondents, and ratings for ecological services increased with recreational rates. Only 20 % of respondents listed specific ecological services as one of their three most important environmental concerns. These data will be useful for increasing preparedness, enhancing educational strategies for shore protection, and providing managers and public policy makers with data essential to developing resiliency strategies.

  3. Personality and Stressor-Related Affect

    Science.gov (United States)

    Leger, Kate A.; Charles, Susan T.; Turiano, Nicholas A.; Almeida, David M.

    2015-01-01

    Greater increases in negative affect and greater decreases in positive affect on days stressors occur portend poorer mental and physical health years later. Although personality traits influence stressor-related affect, only neuroticism and extraversion among the Big Five personality traits have been examined in any detail. Moreover, personality traits may shape how people appraise daily stressors, yet few studies have examined how stressor-related appraisals may account for associations between personality and stressor-related affect. Two studies used participants (N=2022, age 30–84) from the National Study of Daily Experiences II (NSDE II) to examine the associations between Big Five personality traits and stressor-related affect, in addition to how appraisals may account for these relationships. Results from Study 1 indicate that higher levels of extraversion, conscientiousness, and openness to experience, and lower levels of neuroticism, are related to less stressor-related negative affect. Only agreeableness was associated with stressor-related positive affect, such that higher levels were related to greater decreases in positive affect on days stressors occur. The second study found that stressor-related appraisals partially accounted for the significant associations between stressor-related negative affect and personality. Implications for these findings in relation to how personality may influence physical and emotional health are discussed. PMID:26796984

  4. Managing for interactions between local and global stressors of ecosystems.

    Science.gov (United States)

    Brown, Christopher J; Saunders, Megan I; Possingham, Hugh P; Richardson, Anthony J

    2013-01-01

    Global stressors, including climate change, are a major threat to ecosystems, but they cannot be halted by local actions. Ecosystem management is thus attempting to compensate for the impacts of global stressors by reducing local stressors, such as overfishing. This approach assumes that stressors interact additively or synergistically, whereby the combined effect of two stressors is at least the sum of their isolated effects. It is not clear, however, how management should proceed for antagonistic interactions among stressors, where multiple stressors do not have an additive or greater impact. Research to date has focussed on identifying synergisms among stressors, but antagonisms may be just as common. We examined the effectiveness of management when faced with different types of interactions in two systems--seagrass and fish communities--where the global stressor was climate change but the local stressors were different. When there were synergisms, mitigating local stressors delivered greater gains, whereas when there were antagonisms, management of local stressors was ineffective or even degraded ecosystems. These results suggest that reducing a local stressor can compensate for climate change impacts if there is a synergistic interaction. Conversely, if there is an antagonistic interaction, management of local stressors will have the greatest benefits in areas of refuge from climate change. A balanced research agenda, investigating both antagonistic and synergistic interaction types, is needed to inform management priorities.

  5. Managing for interactions between local and global stressors of ecosystems.

    Directory of Open Access Journals (Sweden)

    Christopher J Brown

    Full Text Available Global stressors, including climate change, are a major threat to ecosystems, but they cannot be halted by local actions. Ecosystem management is thus attempting to compensate for the impacts of global stressors by reducing local stressors, such as overfishing. This approach assumes that stressors interact additively or synergistically, whereby the combined effect of two stressors is at least the sum of their isolated effects. It is not clear, however, how management should proceed for antagonistic interactions among stressors, where multiple stressors do not have an additive or greater impact. Research to date has focussed on identifying synergisms among stressors, but antagonisms may be just as common. We examined the effectiveness of management when faced with different types of interactions in two systems--seagrass and fish communities--where the global stressor was climate change but the local stressors were different. When there were synergisms, mitigating local stressors delivered greater gains, whereas when there were antagonisms, management of local stressors was ineffective or even degraded ecosystems. These results suggest that reducing a local stressor can compensate for climate change impacts if there is a synergistic interaction. Conversely, if there is an antagonistic interaction, management of local stressors will have the greatest benefits in areas of refuge from climate change. A balanced research agenda, investigating both antagonistic and synergistic interaction types, is needed to inform management priorities.

  6. Ecosystem stressors in southern Nevada [Chapter 2] (Executive Summary)

    Science.gov (United States)

    Burton K. Pendleton; Jeanne C. Chambers; Matthew L. Brooks; Steven M. Ostoja

    2013-01-01

    Southern Nevada ecosystems are subject to a number of stressors that range in scope from local to regional to global. At the regional scale, human population growth and related activities constitute a major stressor. Nevada has undergone significant change due to unprecedented population growth and ongoing global change processes. Nevada’s growth rate has been the...

  7. Joint analysis of stressors and ecosystem services to enhance restoration effectiveness.

    Science.gov (United States)

    Allan, J David; McIntyre, Peter B; Smith, Sigrid D P; Halpern, Benjamin S; Boyer, Gregory L; Buchsbaum, Andy; Burton, G A; Campbell, Linda M; Chadderton, W Lindsay; Ciborowski, Jan J H; Doran, Patrick J; Eder, Tim; Infante, Dana M; Johnson, Lucinda B; Joseph, Christine A; Marino, Adrienne L; Prusevich, Alexander; Read, Jennifer G; Rose, Joan B; Rutherford, Edward S; Sowa, Scott P; Steinman, Alan D

    2013-01-02

    With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments.

  8. Timing anthropogenic stressors to mitigate their impact on marine ecosystem resilience

    OpenAIRE

    Wu, Paul Pao-Yen; Mengersen, Kerrie; McMahon, Kathryn; Kendrick, Gary A.; Chartrand, Kathryn; York, Paul H.; Rasheed, Michael A.; Caley, M. Julian

    2017-01-01

    Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined...

  9. Interactions among ecosystem stressors and their importance in conservation

    Science.gov (United States)

    Darling, Emily S.; Brown, Christopher J.

    2016-01-01

    Interactions between multiple ecosystem stressors are expected to jeopardize biological processes, functions and biodiversity. The scientific community has declared stressor interactions—notably synergies—a key issue for conservation and management. Here, we review ecological literature over the past four decades to evaluate trends in the reporting of ecological interactions (synergies, antagonisms and additive effects) and highlight the implications and importance to conservation. Despite increasing popularity, and ever-finer terminologies, we find that synergies are (still) not the most prevalent type of interaction, and that conservation practitioners need to appreciate and manage for all interaction outcomes, including antagonistic and additive effects. However, it will not be possible to identify the effect of every interaction on every organism's physiology and every ecosystem function because the number of stressors, and their potential interactions, are growing rapidly. Predicting the type of interactions may be possible in the near-future, using meta-analyses, conservation-oriented experiments and adaptive monitoring. Pending a general framework for predicting interactions, conservation management should enact interventions that are robust to uncertainty in interaction type and that continue to bolster biological resilience in a stressful world. PMID:26865306

  10. Integrated Assessment of the impact of Aqueous Contaminant Stressors on Surface Water Ecosystems

    DEFF Research Database (Denmark)

    McKnight, Ursula S.; Rasmussen, Jes J.; Kronvang, Brian

    2011-01-01

    ecosystems. Traditional approaches for managing aquatic resources have often failed to account for the potential effects of anthropogenic disturbances on biota. To fulfil the requirements of the EU Water Framework Directive will be challenging, as it is difficult to successfully separate and evaluate all...... pressures stressing an ecosystem. Here, methods for determining ecological status in streams are evaluated to see if they are capable of capturing the effects of stressors potentially affecting ecosystems. Specifically, they are tested on a case study where the effects of physical habitat degradation can...... be ruled out as a stressor on stream ecological conditions (Rasmussen et al., 2011). This study follows earlier work conducted on a Danish case study involving a TCE groundwater plume discharging into a small stream, located in an area with protected drinking water interests (McKnight et al., 2010...

  11. Stressors affecting nursing students in Pakistan.

    Science.gov (United States)

    Watson, R; Rehman, S; Ali, P A

    2017-12-01

    To determine factors contributing to stress experienced by preregistration nursing students in Pakistan, using the Stressors in Nursing Students scale. The aim was to explore the psychometric properties of this instrument and to investigate the effect of a range of demographic variables on the perception of stressors in nursing students. Nursing is a stressful profession, and nursing students may experience more stress due to competing demands and challenges of nursing education, assessment, placements and worries about employment prospects. In this cross-sectional survey, data from 726 nursing students from 11 schools of nursing in Karachi, Pakistan, were collected using a questionnaire. Data were analysed using descriptive as well inferential statistics. An exploratory factor analysis was also conducted. There was no apparent factor structure to the Stressors in Nursing Students scale, unlike in previous studies. The total score on the Stressors in Nursing Students scale was related to gender with males scoring higher. The score generally increased over 4 years of the programme, and students in private schools of nursing scored higher than those in public schools of nursing. Nursing students in Pakistan do not appear to differentiate between different stressors, and this may be due to cultural differences in the students and to the structure of the programme and the articulation between the academic and clinical aspects. Likewise, cultural reasons may account for differences between stress experienced by male and female students. The fact that scores on the Stressors in Nursing Students scale increased over 4 years of the programme and males scored higher than females should alert nursing schools and policymakers related to nursing education and workforce to pay attention to prevent attrition from nursing programmes. © 2017 International Council of Nurses.

  12. Rating impacts in a multi-stressor world: a quantitative assessment of 50 stressors affecting the Great Lakes.

    Science.gov (United States)

    Smith, Sigrid D P; Mcintyre, Peter B; Halpern, Benjamin S; Cooke, Roger M; Marino, Adrienne L; Boyer, Gregory L; Buchsbaum, Andy; Burton, G A; Campbell, Linda M; Ciborowski, Jan J H; Doran, Patrick J; Infante, Dana M; Johnson, Lucinda B; Read, Jennifer G; Rose, Joan B; Rutherford, Edward S; Steinman, Alan D; Allan, J David

    2015-04-01

    Ecosystems often experience multiple environmental stressors simultaneously that can differ widely in their pathways and strengths of impact. Differences in the relative impact of environmental stressors can guide restoration and management prioritization, but few studies have empirically assessed a comprehensive suite of stressors acting on a given ecosystem. To fill this gap in the Laurentian Great Lakes, where considerable restoration investments are currently underway, we used expert elicitation via a detailed online survey to develop ratings of the relative impacts of 50 potential stressors. Highlighting the multiplicity of stressors in this system, experts assessed all 50 stressors as having some impact on ecosystem condition, but ratings differed greatly among stressors. Individual stressors related to invasive and nuisance species (e.g., dreissenid mussels and ballast invasion risk) and climate change were assessed as having the greatest potential impacts. These results mark a shift away from the longstanding emphasis on nonpoint phosphorus and persistent bioaccumulative toxic substances in the Great Lakes. Differences in impact ratings among lakes and ecosystem zones were weak, and experts exhibited surprisingly high levels of agreement on the relative impacts of most stressors. Our results provide a basin-wide, quantitative summary of expert opinion on the present-day influence of all major Great Lakes stressors. The resulting ratings can facilitate prioritizing stressors to achieve management objectives in a given location, as well as providing a baseline for future stressor impact assessments in the Great Lakes and elsewhere.

  13. Integrated assessment of the impact of chemical stressors on surface water ecosystems

    DEFF Research Database (Denmark)

    McKnight, Ursula S; Rasmussen, Jes J; Kronvang, Brian

    2012-01-01

    of chemical stressors on stream ecosystems are evaluated for a stream in Denmark where the effects of major physical habitat degradation can be disregarded. The methods are: (i) the Danish Stream Fauna Index, (ii) Toxic Units (TU), (iii) SPEAR indices, (iv) Hazard Quotient (HQ) index and (v) AQUATOX...... of this case study, the HQ index and AQUATOX were extended for additional compounds, not only partly to identify potential compounds of concern, but also to determine thresholds where ecological impacts could be expected to occur. The results demonstrate that some commonly used methods for the assessment...... of ecological impact are not sufficient for capturing - and ideally separating - the effects of all anthropogenic stressors affecting ecosystems. Predictive modelling techniques can be especially useful in supporting early decisions on prioritising hot spots, serving to identify knowledge gaps and thereby...

  14. Urban development results in stressors that degrade stream ecosystems

    Science.gov (United States)

    Bell, Amanda H.; Coles, James F.; McMahon, Gerard; Woodside, Michael D.

    2012-01-01

    In 2003, eighty-three percent of Americans lived in metropolitan areas, and considerable population increases are predicted within the next 50 years. Nowhere are the environmental changes associated with urban development more evident than in urban streams. Contaminants, habitat destruction, and increasing streamflow flashiness resulting from urban development have been associated with the disruption of biological communities, particularly the loss of sensitive aquatic biota. Every stream is connected downstream to other water bodies, and inputs of contaminants and (or) sediments to streams can cause degradation downstream with adverse effects on biological communities and on economically valuable resources, such as fisheries and tourism. Understanding how algal, invertebrate, and fish communities respond to physical and chemical stressors associated with urban development can provide important clues on how multiple stressors may be managed to protect stream health as a watershed becomes increasingly urbanized. This fact sheet highlights selected findings of a comprehensive assessment by the National Water-Quality Assessment Program of the U.S. Geological Survey (USGS) of the effects of urban development on stream ecosystems in nine metropolitan study areas.

  15. Affective reactivity to daily stressors is associated with elevated inflammation.

    Science.gov (United States)

    Sin, Nancy L; Graham-Engeland, Jennifer E; Ong, Anthony D; Almeida, David M

    2015-12-01

    Inflammation increases the risk of chronic diseases, but the links between emotional responses to daily events and inflammation are unknown. We examined individual differences in affective reactivity to daily stressors (i.e., changes in positive and negative affect in response to stressors) as predictors of inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). A cross-sectional sample of 872 adults from the National Study of Daily Experiences (substudy of Midlife in the United States II) reported daily stressors and affect during telephone interviews for 8 days. Blood samples were obtained at a separate clinic visit and assayed for inflammatory markers. Multilevel models estimated trait affective reactivity slopes for each participant, which were inputted into regression models to predict inflammation. People who experienced greater decreases in positive affect on days when stressors occurred (i.e., positive affect reactivity) had elevated log IL-6, independent of demographic, physical, psychological, and behavioral factors (B = 1.12, SE = 0.45, p = .01). Heightened negative affect reactivity was associated with higher log CRP among women (p = .03) but not men (p = .57); health behaviors accounted for this association in women. Adults who fail to maintain positive affect when faced with minor stressors in everyday life appear to have elevated levels of IL-6, a marker of inflammation. Women who experience increased negative affect when faced with minor stressors may be at particular risk of elevated inflammation. These findings add to growing evidence regarding the health implications of affective reactivity to daily stressors. (c) 2015 APA, all rights reserved).

  16. Affective reactivity to daily stressors is associated with elevated inflammation

    Science.gov (United States)

    Sin, Nancy L.; Graham-Engeland, Jennifer E.; Ong, Anthony D.; Almeida, David M.

    2015-01-01

    Objective Inflammation increases the risk of chronic diseases, but the links between emotional responses to daily events and inflammation are unknown. We examined individual differences in affective reactivity to daily stressors (i.e., changes in positive and negative affect in response to stressors) as predictors of inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). Methods A cross-sectional sample of 872 adults from the National Study of Daily Experiences (sub-study of Midlife in the United States II) reported daily stressors and affect during telephone interviews for 8 days. Blood samples were obtained at a separate clinic visit and assayed for inflammatory markers. Multilevel models estimated trait affective reactivity slopes for each participant, which were inputted into regression models to predict inflammation. Results People who experienced greater decreases in positive affect on days when stressors occurred (i.e, positive affect reactivity) had elevated log IL-6, independent of demographic, physical, psychological, and behavioral factors (B = 1.12, SE = 0.45, p = 0.01). Heightened negative affect reactivity was associated with higher log CRP among women (p = 0.03) but not men (p = 0.57); health behaviors accounted for this association in women. Conclusions Adults who fail to maintain positive affect when faced with minor stressors in everyday life appear to have elevated levels of IL-6, a marker of inflammation. Women who experience increased negative affect when faced with minor stressors may be at particular risk of elevated inflammation. These findings add to growing evidence regarding the health implications of affective reactivity to daily stressors. PMID:26030309

  17. Multiple stressors, nonlinear effects and the implications of climate change impacts on marine coastal ecosystems.

    Science.gov (United States)

    Hewitt, Judi E; Ellis, Joanne I; Thrush, Simon F

    2016-08-01

    Global climate change will undoubtedly be a pressure on coastal marine ecosystems, affecting not only species distributions and physiology but also ecosystem functioning. In the coastal zone, the environmental variables that may drive ecological responses to climate change include temperature, wave energy, upwelling events and freshwater inputs, and all act and interact at a variety of spatial and temporal scales. To date, we have a poor understanding of how climate-related environmental changes may affect coastal marine ecosystems or which environmental variables are likely to produce priority effects. Here we use time series data (17 years) of coastal benthic macrofauna to investigate responses to a range of climate-influenced variables including sea-surface temperature, southern oscillation indices (SOI, Z4), wind-wave exposure, freshwater inputs and rainfall. We investigate responses from the abundances of individual species to abundances of functional traits and test whether species that are near the edge of their tolerance to another stressor (in this case sedimentation) may exhibit stronger responses. The responses we observed were all nonlinear and some exhibited thresholds. While temperature was most frequently an important predictor, wave exposure and ENSO-related variables were also frequently important and most ecological variables responded to interactions between environmental variables. There were also indications that species sensitive to another stressor responded more strongly to weaker climate-related environmental change at the stressed site than the unstressed site. The observed interactions between climate variables, effects on key species or functional traits, and synergistic effects of additional anthropogenic stressors have important implications for understanding and predicting the ecological consequences of climate change to coastal ecosystems. © 2015 John Wiley & Sons Ltd.

  18. Managing the effects of multiple stressors on aquatic ecosystems under water scarcity. The GLOBAQUA project.

    Science.gov (United States)

    Navarro-Ortega, Alícia; Acuña, Vicenç; Bellin, Alberto; Burek, Peter; Cassiani, Giorgio; Choukr-Allah, Redouane; Dolédec, Sylvain; Elosegi, Arturo; Ferrari, Federico; Ginebreda, Antoni; Grathwohl, Peter; Jones, Colin; Rault, Philippe Ker; Kok, Kasper; Koundouri, Phoebe; Ludwig, Ralf Peter; Merz, Ralf; Milacic, Radmila; Muñoz, Isabel; Nikulin, Grigory; Paniconi, Claudio; Paunović, Momir; Petrovic, Mira; Sabater, Laia; Sabaterb, Sergi; Skoulikidis, Nikolaos Th; Slob, Adriaan; Teutsch, Georg; Voulvoulis, Nikolaos; Barceló, Damià

    2015-01-15

    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA. Copyright © 2014. Published by Elsevier B.V.

  19. Managing the effects of multiple stressors on aquatic ecosystems under water scarcity. The GLOBAQUA project

    Science.gov (United States)

    Navarro-Ortega, Alícia; Acuña, Vicenç; Bellin, Alberto; Burek, Peter; Cassiani, Giorgio; Choukr-Allah, Redouane; Dolédec, Sylvain; Elosegi, Arturo; Ferrari, Federico; Ginebreda, Antoni; Grathwohl, Peter; Jones, Colin; Rault, Philippe Ker; Kok, Kasper; Koundouri, Phoebe; Ludwig, Ralf Peter; Merz, Ralf; Milacic, Radmila; Muñoz, Isabel; Nikulin, Grigory; Paniconi, Claudio; Paunović, Momir; Petrovic, Mira; Sabater, Laia; Sabaterb, Sergi; Skoulikidis, Nikolaos Th.; Slob, Adriaan; Teutsch, Georg; Voulvoulis, Nikolaos; Barceló, Damià

    2015-01-01

    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA. PMID:25005236

  20. A Framework to Quantify the Strength of the Ecological Links Between an Environmental Stressor and Final Ecosystem Services

    Science.gov (United States)

    Anthropogenic stressors such as climate change, fire, and pollution are driving shifts in ecosystem function and resilience. Scientists generally rely on biological indicators of these stressors to signal that ecosystem conditions have been altered beyond an acceptable amount. Ho...

  1. 76 FR 55060 - Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi-Stressor...

    Science.gov (United States)

    2011-09-06

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9459-7] Aquatic Ecosystems, Water Quality, and Global Change... entitled, Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi- stressor... vulnerability of water quality and aquatic ecosystems across the United States to the potential impacts of...

  2. Timing anthropogenic stressors to mitigate their impact on marine ecosystem resilience.

    Science.gov (United States)

    Wu, Paul Pao-Yen; Mengersen, Kerrie; McMahon, Kathryn; Kendrick, Gary A; Chartrand, Kathryn; York, Paul H; Rasheed, Michael A; Caley, M Julian

    2017-11-02

    Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging campaigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although the timing and length of windows vary among sites to some degree, global trends indicate favourable windows in autumn and winter. Our results demonstrate that resilience is dynamic with respect to space, time and stressors, varying most strongly with: (i) the life history of the seagrass genus and (ii) the duration and timing of the impacting stress.

  3. Sustainability Of Coastal Fringe Ecosystems Against Anthropogenic Chemical Stressors

    Science.gov (United States)

    Plant-dominated coastal ecosystems provide least 21 ecological services including shoreline protection, contaminant removal and nursery and breeding habitat for biota. The value of these ecological services is as great as $28000/h. These ecosystems which include intertidal wetl...

  4. Structure, functioning, and cumulative stressors of Mediterranean deep-sea ecosystems

    OpenAIRE

    Tecchio, S.; Coll, Marta; Sarda, F.

    2015-01-01

    Environmental stressors, such as climate fluctuations, and anthropogenic stressors, such as fishing, are of major concern for the management of deep-sea ecosystems. Deep-water habitats are limited by primary productivity and are mainly dependent on the vertical input of organic matter from the surface. Global change over the latest decades is imparting variations in primary productivity levels across oceans, and thus it has an impact on the amount of organic matter landing on the deep seafloo...

  5. Diagnosis of potential stressors adversely affecting benthic invertebrate communities in Greenwich Bay, Rhode Island, USA

    Science.gov (United States)

    Greenwich Bay is an urbanized embayment of Narragansett Bay potentially impacted by multiple stressors. The present study identified the important stressors affecting Greenwich Bay benthic fauna. First, existing data and information were used to confirm that the waterbody was imp...

  6. Accounting for multiple stressors in regional stream ecosystem analysis: A demonstration with riparian invasive plants

    Science.gov (United States)

    Background/Questions/Methods: Large cross-sectional data sets allow testing of hypotheses about how one part of an ecosystem relates to other parts. Tests such as these are of interest for many reasons, one of which is to gain insight into the role of stressors, such as land co...

  7. Ash in fire affected ecosystems

    Science.gov (United States)

    Pereira, Paulo; Jordan, Antonio; Cerda, Artemi; Martin, Deborah

    2015-04-01

    Ash in fire affected ecosystems Ash lefts an important footprint in the ecosystems and has a key role in the immediate period after the fire (Bodi et al., 2014; Pereira et al., 2015). It is an important source of nutrients for plant recover (Pereira et al., 2014a), protects soil from erosion and controls soil hydrological process as runoff, infiltration and water repellency (Cerda and Doerr, 2008; Bodi et al., 2012, Pereira et al., 2014b). Despite the recognition of ash impact and contribution to ecosystems recuperation, it is assumed that we still have little knowledge about the implications of ash in fire affected areas. Regarding this situation we wanted to improve our knowledge in this field and understand the state of the research about fire ash around world. The special issue about "The role of ash in fire affected ecosystems" currently in publication in CATENA born from the necessity of joint efforts, identify research gaps, and discuss future cooperation in this interdisciplinary field. This is the first special issue about fire ash in the international literature. In total it will be published 10 papers focused in different aspects of the impacts of ash in fire affected ecosystems from several parts of the world: • Fire reconstruction using charcoal particles (Burjachs and Espositio, in press) • Ash slurries impact on rheological properties of Runoff (Burns and Gabet, in press) • Methods to analyse ash conductivity and sorbtivity in the laboratory and in the field (Balfour et al., in press) • Termogravimetric and hydrological properties of ash (Dlapa et al. in press) • Effects of ash cover in water infiltration (Leon et al., in press) • Impact of ash in volcanic soils (Dorta Almenar et al., in press; Escuday et al., in press) • Ash PAH and Chemical extracts (Silva et al., in press) • Microbiology (Barreiro et al., in press; Lombao et al., in press) We believe that this special issue will contribute importantly to the better understanding of

  8. Fewer ups and downs: daily stressors mediate age differences in negative affect.

    Science.gov (United States)

    Charles, Susan Turk; Luong, Gloria; Almeida, David M; Ryff, Carol; Sturm, Maggie; Love, Gayle

    2010-05-01

    The current study examined age differences in daily stressors, positive events (uplifts), and their associations with emotional experience among healthy older women. Women (N = 101, 63-93 years old) reported their daily experiences across 1 week. Older age was related to fewer stressors and less frequent negative affect. However, the association between negative affect and age was no longer significant after accounting for the occurrence of daily stressors. Older age was not significantly related to positive affect, although positive uplifts were reported less frequently with age. Findings provide a contextual explanation for emotional experience in very late life, where reduced exposure to stressors partially explains age-related reductions in negative affect.

  9. Fewer Ups and Downs: Daily Stressors Mediate Age Differences in Negative Affect

    OpenAIRE

    Charles, Susan Turk; Luong, Gloria; Almeida, David M.; Ryff, Carol; Sturm, Maggie; Love, Gayle

    2010-01-01

    The current study examined age differences in daily stressors, positive events (uplifts), and their associations with emotional experience among healthy older women. Women (N = 101, 63--93 years old) reported their daily experiences across 1 week. Older age was related to fewer stressors and less frequent negative affect. However, the association between negative affect and age was no longer significant after accounting for the occurrence of daily stressors. Older age was not significantly re...

  10. Chronic and Daily Stressors Along With Negative Affect Interact to Predict Daily Tiredness.

    Science.gov (United States)

    Hartsell, Elizabeth N; Neupert, Shevaun D

    2017-11-01

    The present study examines the within-person relationship of daily stressors and tiredness and whether this depends on daily negative affect and individual differences in chronic stress. One hundred sixteen older adult participants were recruited via Amazon's Mechanical Turk for a 9-day daily diary study. Daily tiredness, daily stressors, and negative affect were measured each day, and chronic stress was measured at baseline. Daily stressors, daily negative affect, and chronic stress interacted to predict daily tiredness. People with high chronic stress who experienced an increase in daily negative affect were the most reactive to daily stressors in terms of experiencing an increase in daily tiredness. We also found that people with low levels of chronic stress were the most reactive to daily stressors when they experienced low levels of daily negative affect. Our results highlight the need for individualized and contextualized approaches to combating daily tiredness in older adults.

  11. Structure, functioning, and cumulative stressors of Mediterranean deep-sea ecosystems

    Science.gov (United States)

    Tecchio, Samuele; Coll, Marta; Sardà, Francisco

    2015-06-01

    Environmental stressors, such as climate fluctuations, and anthropogenic stressors, such as fishing, are of major concern for the management of deep-sea ecosystems. Deep-water habitats are limited by primary productivity and are mainly dependent on the vertical input of organic matter from the surface. Global change over the latest decades is imparting variations in primary productivity levels across oceans, and thus it has an impact on the amount of organic matter landing on the deep seafloor. In addition, anthropogenic impacts are now reaching the deep ocean. The Mediterranean Sea, the largest enclosed basin on the planet, is not an exception. However, ecosystem-level studies of response to varying food input and anthropogenic stressors on deep-sea ecosystems are still scant. We present here a comparative ecological network analysis of three food webs of the deep Mediterranean Sea, with contrasting trophic structure. After modelling the flows of these food webs with the Ecopath with Ecosim approach, we compared indicators of network structure and functioning. We then developed temporal dynamic simulations varying the organic matter input to evaluate its potential effect. Results show that, following the west-to-east gradient in the Mediterranean Sea of marine snow input, organic matter recycling increases, net production decreases to negative values and trophic organisation is overall reduced. The levels of food-web activity followed the gradient of organic matter availability at the seafloor, confirming that deep-water ecosystems directly depend on marine snow and are therefore influenced by variations of energy input, such as climate-driven changes. In addition, simulations of varying marine snow arrival at the seafloor, combined with the hypothesis of a possible fishery expansion on the lower continental slope in the western basin, evidence that the trawling fishery may pose an impact which could be an order of magnitude stronger than a climate

  12. The Effects of Daily Co-Occurrence of Affect on Older Adults’ Reactivity to Health Stressors

    Science.gov (United States)

    Ramsey, Jennifer L.; Neupert, Shevaun D.; Mroczek, Daniel K.; Spiro, Avron

    2015-01-01

    Objectives The present study examined age differences among older adults in the daily co-occurrence of affect and its potential role in buffering the negative effects of health stressors. Design Participants were from the Veterans Affairs Normative Aging Study (NAS) and included 249 young-old adults (age = 60–79 years, M=71.6) and 64 old-old adults (age = 80–89, M = 82.9) who completed questionnaires assessing stressors, physical health symptoms, and positive and negative affect on eight consecutive days. Results An independent samples t-test showed young-old and old-old adults did not significantly differ in their mean levels of daily co-occurrence of affect. The between-person relationships among stressors, health, and daily co-occurrence of affect revealed that neither stressors nor health were significantly related to daily co-occurrence of affect. However, results from a multilevel model revealed a three-way cross-level interaction (Health Stressor X Age Group X Co-Occurrence of Affect) where old-old adults with higher levels of co-occurrence of affect were less emotionally reactive to health stressors than young-old adults. Conclusion These findings provide support for the assertion that co-occurrence of affect functions in an adaptive capacity and highlight the importance of examining domain specific stressors. PMID:26518259

  13. The effects of daily co-occurrence of affect on older adults' reactivity to health stressors.

    Science.gov (United States)

    Ramsey, Jennifer L; Neupert, Shevaun D; Mroczek, Daniel K; Spiro, Avron

    2016-01-01

    The present study examined age differences among older adults in the daily co-occurrence of affect and its potential role in buffering the negative effects of health stressors. Participants were from the Veterans Affairs Normative Aging Study and included 249 young-old adults (age = 60-79 years, M = 71.6) and 64 old-old adults (age = 80-89, M = 82.9) who completed questionnaires assessing stressors, physical health symptoms, and positive and negative affect for eight consecutive days. An independent samples t-test showed young-old and old-old adults did not significantly differ in their mean levels of daily co-occurrence of affect. The between-person relationships among stressors, health and daily co-occurrence of affect revealed that neither stressors nor health were significantly related to daily co-occurrence of affect. However, results from a multilevel model revealed a three-way cross-level interaction (health stressor × age group × co-occurrence of affect) where old-old adults with higher levels of co-occurrence of affect were less emotionally reactive to health stressors than young-old adults. These findings provide support for the assertion that co-occurrence of affect functions in an adaptive capacity and highlight the importance of examining domain-specific stressors.

  14. Chemical and non-chemical stressors affecting childhood obesity: a systematic scoping review.

    Science.gov (United States)

    Lichtveld, Kim; Thomas, Kent; Tulve, Nicolle S

    2018-01-01

    Childhood obesity in the United States has doubled over the last three decades and currently affects 17% of children and adolescents. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stressors found in a child's environment and how these interactions affect a child's health and well-being. The objectives of this systematic scoping review were to (1) identify potential chemical stressors in the context of non-chemical stressors that impact childhood obesity; and, (2) summarize our observations for chemical and non-chemical stressors in regards to child-specific environments within a community setting. A review was conducted to identify chemical and non-chemical stressors related to childhood obesity for the childhood life stages ranging from prenatal to adolescence. Stressors were identified and grouped into domains: individual behaviors, family/household behaviors, community stressors, and chemical exposures. Stressors were related to the child and the child's everyday environments and used to characterize child health and well-being. This review suggests that the interactions of chemical and non-chemical stressors are important for understanding a child's overall health and well-being. By considering these relationships, the exposure science research community can better design and implement strategies to reduce childhood obesity.

  15. When things don't add up: quantifying impacts of multiple stressors from individual metabolism to ecosystem processing.

    Science.gov (United States)

    Galic, Nika; Sullivan, Lauren L; Grimm, Volker; Forbes, Valery E

    2018-04-01

    Ecosystems are exposed to multiple stressors which can compromise functioning and service delivery. These stressors often co-occur and interact in different ways which are not yet fully understood. Here, we applied a population model representing a freshwater amphipod feeding on leaf litter in forested streams. We simulated impacts of hypothetical stressors, individually and in pairwise combinations that target the individuals' feeding, maintenance, growth and reproduction. Impacts were quantified by examining responses at three levels of biological organisation: individual-level body sizes and cumulative reproduction, population-level abundance and biomass and ecosystem-level leaf litter decomposition. Interactive effects of multiple stressors at the individual level were mostly antagonistic, that is, less negative than expected. Most population- and ecosystem-level responses to multiple stressors were stronger than expected from an additive model, that is, synergistic. Our results suggest that across levels of biological organisation responses to multiple stressors are rarely only additive. We suggest methods for efficiently quantifying impacts of multiple stressors at different levels of biological organisation. © 2018 John Wiley & Sons Ltd/CNRS.

  16. Stressors, locus of control, and social support as consequences of affective psychological well-being.

    Science.gov (United States)

    Daniels, K; Guppy, A

    1997-04-01

    Tests of the influence of affective psychological well-being on stressors, locus of control, and social support in a 1-month follow-up study of 210 male and 34 female British accountants is reported. There was a marginally significant association between the level of psychological symptoms and subsequent reports of intensity of quantitative workload stressors. A significant interaction between psychological symptoms and a measure of depression-enthusiasm was found to predict subsequent locus of control. The results indicate a differential pattern of associations between aspects of affective well-being and subsequent reports of social support. The results also indicate that initially more frequent stressors are associated with subsequently less intense stressors of the same type. The findings highlight the dynamic and reciprocal nature of the occupational stress process.

  17. The Range and Impact of Postmigration Stressors During Treatment of Trauma-Affected Refugees.

    Science.gov (United States)

    Bruhn, Maja; Rees, Susan; Mohsin, Mohammed; Silove, Derrick; Carlsson, Jessica

    2018-01-01

    Trauma-affected refugees commonly experience postmigration stressors, which can compound conflict-related emotional distress. Our study aimed to assess clinician-rated frequency and types of postmigration stressors deemed to be interfering with the treatment of refugees attending a service for trauma-related mental distress. A total of 116 patients completed 6 months of multidisciplinary treatment. Clinician-rated postmigration stressors were registered at each session. Outcome measures were Harvard Trauma Questionnaire and Global Assessment of Functioning, function (GAF-F) and symptom. Postmigration stressors were deemed to impact on 39.1% of treatment sessions with medical personnel. Issues related to work, finances, and family were the most frequently identified stressors. Postmigration stressors interfering with treatment were more common among male refugees, those living alone, those from Middle Eastern origin, and persons with low baseline GAF-F. Explicitly identifying and, where possible, dealing with postmigration stressors may assist in averting their interference with the treatment of distress in refugees.

  18. Let It Go: Lingering Negative Affect in Response to Daily Stressors Is Associated With Physical Health Years Later.

    Science.gov (United States)

    Leger, Kate A; Charles, Susan T; Almeida, David M

    2018-03-01

    The way we respond to life's daily stressors has strong implications for our physical health. Researchers have documented the detrimental effects of initial emotional reactivity to daily stressors on future physical health outcomes but have yet to examine the effects of emotions that linger after a stressor occurs. The current study investigated how negative affect that lingers the day after a minor stressor occurs is associated with health-related outcomes. Participants ( N = 1,155) in a community-based, nationwide study answered questions about daily stressors and affect across 8 consecutive days and about their physical health almost 10 years later. Multilevel models indicated that people experience heightened levels of negative affect the day after a stressor occurs. Furthermore, higher levels of lingering negative affect are associated with greater numbers of chronic conditions and worse functional limitations 10 years later. Findings suggest that affective recovery from daily stressors has unique importance for long-term physical health.

  19. Disclosure of psychosocial stressors affecting diabetes care among uninsured young adults with Type 1 diabetes.

    Science.gov (United States)

    Pyatak, E A; Sequeira, P; Peters, A L; Montoya, L; Weigensberg, M J

    2013-09-01

    To determine the disclosure rates of psychosocial issues affecting routine diabetes care. A total of 20 young adults were interviewed regarding the impact of psychosocial stressors on their diabetes care. The interviewer, endocrinologist and case manager reported the prevalence rates of psychosocial stressors. Disclosure rates were compared to determine the prevalence of psychosocial issues and the different patterns of disclosure. Participants reported a high number of psychosocial stressors, which were associated with poorer glycaemic control (r = 0.60, P = 0.005). Approximately half of all disclosed stressors (50.9%) were identified in routine care; other stressors were identified only through intensive case management and/or in-depth interviews. Identifying psychosocial stressors in routine care, and providing referrals to psychological or social services, is a significant unmet need and may improve glycaemic control among certain populations with diabetes. Systematic mechanisms of capturing this information, such as by screening surveys, should be considered. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

  20. Coping with Challenge and Hindrance Stressors in Teams: Behavioral, Cognitive, and Affective Outcomes

    Science.gov (United States)

    Pearsall, Matthew J.; Ellis, Aleksander P. J.; Stein, Jordan H.

    2009-01-01

    The purpose of this study was to utilize the challenge-hindrance framework to examine the discrete and combined effects of different environmental stressors on behavioral, cognitive, and affective outcomes at the team level. Results from 83 teams working on a command and control simulation indicated that the introduction of a challenge stressor…

  1. A new contribution to the classification of stressors affecting nursing professionals

    Directory of Open Access Journals (Sweden)

    Jesús Cremades Puerto

    Full Text Available Objective: to identify and classify the most important occupational stressors affecting nursing professionals in the medical units within a hospital. Method: quantitative-qualitative, descriptive and prospective study performed with Delphi technique in the medical units of a general university hospital, with a sample of 30 nursing professionals. Results: the stressors were work overload, frequent interruptions in the accomplishment of their tasks, night working, simultaneity of performing different tasks, not having enough time to give emotional support to the patient or lack of time for some patients who need it, among others. Conclusion: the most consensual stressors were ranked as work overload, frequent interruptions in the accomplishment of their tasks, night working and, finally, simultaneity of performing different tasks. These results can be used as a tool in the clinical management of hospital units, aiming to improve the quality of life of nursing professionals, organizational models and, in addition, continuous improvement in clinical treatment.

  2. Effects of Social Exclusion on Cardiovascular and Affective Reactivity to a Socially Evaluative Stressor.

    Science.gov (United States)

    Williamson, Timothy J; Thomas, KaMala S; Eisenberger, Naomi I; Stanton, Annette L

    2018-04-03

    Socially disconnected individuals have worse health than those who feel socially connected. The mechanisms through which social disconnection influences physiological and psychological outcomes warrant study. The current study tested whether experimental manipulations of social exclusion, relative to inclusion, influenced subsequent cardiovascular (CV) and affective reactivity to socially evaluative stress. Young adults (N = 81) were assigned through block randomization to experience either social exclusion or inclusion, using a standardized computer-based task (Cyberball). Immediately after exposure to Cyberball, participants either underwent a socially evaluative stressor or an active control task, based on block randomization. Physiological activity (systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR)) and state anxiety were assessed throughout the experiment. Excluded participants evidenced a significant increase in cardiovascular and affective responses to a socially evaluative stressor. Included participants who underwent the stressor evidenced similar increases in anxiety, but systolic blood pressure, diastolic blood pressure, and heart rate did not change significantly in response to the stressor. Results contribute to the understanding of physiological consequences of social exclusion. Further investigation is needed to test whether social inclusion can buffer CV stress reactivity, which would carry implications for how positive social factors may protect against the harmful effects of stress.

  3. Shifting Pacific storm tracks as stressors to ecosystems of western North America.

    Science.gov (United States)

    Dannenberg, Matthew P; Wise, Erika K

    2017-11-01

    Much of the precipitation delivered to western North America arrives during the cool season via midlatitude Pacific storm tracks, which may experience future shifts in response to climate change. Here, we assess the sensitivity of the hydroclimate and ecosystems of western North America to the latitudinal position of cool-season Pacific storm tracks. We calculated correlations between storm track variability and three hydroclimatic variables: gridded cool-season standardized precipitation-evapotranspiration index, April snow water equivalent, and water year streamflow from a network of USGS stream gauges. To assess how historical storm track variability affected ecosystem processes, we derived forest growth estimates from a large network of tree-ring widths and land surface phenology and wildfire estimates from remote sensing. From 1980 to 2014, cool-season storm tracks entered western North America between approximately 41°N and 53°N. Cool-season moisture supply and snowpack responded strongly to storm track position, with positive correlations to storm track latitude in eastern Alaska and northwestern Canada but negative correlations in the northwestern U.S. Ecosystems of the western United States were greener and more productive following winters with south-shifted storm tracks, while Canadian ecosystems were greener in years when the cool-season storm track was shifted to the north. On average, larger areas of the northwestern United States were burned by moderate to high severity wildfires when storm tracks were displaced north, and the average burn area per fire also tended to be higher in years with north-shifted storm tracks. These results suggest that projected shifts of Pacific storm tracks over the 21st century would likely alter hydroclimatic and ecological regimes in western North America, particularly in the northwestern United States, where moisture supply and ecosystem processes are highly sensitive to the position of cool-season storm tracks.

  4. Impacts of multiple stressors on ecosystem function: Leaf decomposition in constructed urban wetlands

    International Nuclear Information System (INIS)

    Mackintosh, Teresa J.; Davis, Jenny A.; Thompson, Ross M.

    2016-01-01

    The impact of stormwater on stream biota is well documented, but less is known about the impacts on ecosystem processes, such as the breakdown of organic matter. This study sought to establish whether the degree of urbanisation affected rates of leaf-litter breakdown within constructed wetlands. A litter bag method was used to ascertain rate of decomposition along a gradient of urbanisation (total imperviousness, TI), in constructed wetlands in western and south-eastern Melbourne. A significant positive relationship between TI and breakdown rate was found in the south-eastern wetlands. The significant reduction in rate of invertebrate-mediated breakdown with increasing concentration of certain metals was consistent with other studies. However, overall there was an increase in rate of breakdown. Studies have shown that the effects of heavy metals can be negated if nutrient levels are high. Our results suggest that other parameters besides exposure to contaminants are likely to affect leaf litter breakdown. - Highlights: • There have been few studies on the effect of urbanisation on ecosystem function. • Rate of leaf litter breakdown increased moving along a gradient of urbanisation. • There was a reduction in invertebrate mediated breakdown with certain metals. • Results suggest other parameters besides contaminants affect leaf litter breakdown. - Certain heavy metals led to a decrease in leaf litter breakdown; however overall, there was a positive relationship between breakdown and increasing urbanisation.

  5. 76 FR 10892 - Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi-Stressor...

    Science.gov (United States)

    2011-02-28

    ...: EPA is announcing the release of the draft report titled, ``Aquatic Ecosystems, Water Quality, and... relative vulnerability of water quality and aquatic ecosystems, across the United States, to the potential... mailing address, and the document title, ``Aquatic Ecosystems, Water Quality, and Global Change...

  6. Ecological Production Functions Linking Multiple Stressors to Ecosystem Services – A Case Study

    Science.gov (United States)

    The ecosystem services concept is being used to frame environmental protection goals that guide management of the risks of chemicals. Ecosystem services link changes in ecological systems to the benefits received by people. The use of ecosystem services in risk assessments and th...

  7. Impacts of multiple stressors on ecosystem function: Leaf decomposition in constructed urban wetlands.

    Science.gov (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2016-01-01

    The impact of stormwater on stream biota is well documented, but less is known about the impacts on ecosystem processes, such as the breakdown of organic matter. This study sought to establish whether the degree of urbanisation affected rates of leaf-litter breakdown within constructed wetlands. A litter bag method was used to ascertain rate of decomposition along a gradient of urbanisation (total imperviousness, TI), in constructed wetlands in western and south-eastern Melbourne. A significant positive relationship between TI and breakdown rate was found in the south-eastern wetlands. The significant reduction in rate of invertebrate-mediated breakdown with increasing concentration of certain metals was consistent with other studies. However, overall there was an increase in rate of breakdown. Studies have shown that the effects of heavy metals can be negated if nutrient levels are high. Our results suggest that other parameters besides exposure to contaminants are likely to affect leaf litter breakdown. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Re-thinking stressor interactions: The role of groundwater contamination impacting stream ecosystems

    DEFF Research Database (Denmark)

    McKnight, Ursula S.; Sonne, Anne Thobo; Rønde, Vinni Kampman

    ) to quantify the contaminant discharges, and potentially link the chemical impact and stream water quality. Potential pollution sources include two contaminated sites (Grindstedfactory/landfill), aquaculture, waste water discharges, and diffuse sources from agriculture and urban areas. Datafor xenobiotic...... chronic stress level, so even small perturbations on top of changes in water flow or additional chemical stressors may be detrimental to the stream health. To address this issue, we identified contaminant sources and chemical stressors along a 16-km groundwater-fedstream stretch (Grindsted, Denmark...... organic groundwater contaminants, pesticides, heavy metals, general water chemistry, physical conditions and stream flow from three campaigns in 2012 and 2014 were assessed. The measured chemicalconcentrations were converted to toxic units (TU) based on 48-h acute toxicity tests with Daphnia magna...

  9. Feeling old today? Daily health, stressors, and affect explain day-to-day variability in subjective age.

    Science.gov (United States)

    Kotter-Grühn, Dana; Neupert, Shevaun D; Stephan, Yannick

    2015-01-01

    Subjective age is an important correlate of health, well-being, and longevity. So far, little is known about short-term variability in subjective age and the circumstances under which individuals feel younger/older in daily life. This study examined whether (a) older adults' felt age fluctuates on a day-to-day basis, (b) daily changes in health, stressors, and affect explain fluctuations in felt age, and (c) the daily associations between felt age and health, stressors, or affect are time-ordered. Using an eight-day daily diary approach, N = 43 adults (60-96 years, M = 74.65, SD = 8.19) filled out daily questionnaires assessing subjective age, health, daily stressors, and affect. Data were analysed using multilevel modelling. Subjective age, health, daily stressors, affect. Intra-individual variability in felt age was not explained by time but by short-term variability in other variables. Specifically, on days when participants experienced more than average health problems, stress, or negative affect they felt older than on days with average health, stress, or negative affect. No time-ordered effects were found. Bad health, many stressors, and negative affective experiences constitute circumstances under which older adults feel older than they typically do. Thus, daily measures of subjective age could be markers of health and well-being.

  10. Superorganism resilience: Eusociality and susceptibility of ecosystem service providing insects to stressors

    Science.gov (United States)

    Insects provide crucial ecosystem services for human food security and maintenance of biodiversity. Therefore, major declines in wild species combined with losses of managed bees have raised concern over the sustainability of their ecosystem services. Recent data suggest that honey bees appear to be...

  11. An Integrated Modeling Framework Forecasting Ecosystem Exposure-- A Systems Approach to the Cumulative Impacts of Multiple Stressors

    Science.gov (United States)

    Johnston, J. M.

    2013-12-01

    Freshwater habitats provide fishable, swimmable and drinkable resources and are a nexus of geophysical and biological processes. These processes in turn influence the persistence and sustainability of populations, communities and ecosystems. Climate change and landuse change encompass numerous stressors of potential exposure, including the introduction of toxic contaminants, invasive species, and disease in addition to physical drivers such as temperature and hydrologic regime. A systems approach that includes the scientific and technologic basis of assessing the health of ecosystems is needed to effectively protect human health and the environment. The Integrated Environmental Modeling Framework 'iemWatersheds' has been developed as a consistent and coherent means of forecasting the cumulative impact of co-occurring stressors. The Framework consists of three facilitating technologies: Data for Environmental Modeling (D4EM) that automates the collection and standardization of input data; the Framework for Risk Assessment of Multimedia Environmental Systems (FRAMES) that manages the flow of information between linked models; and the Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE) that provides post-processing and analysis of model outputs, including uncertainty and sensitivity analysis. Five models are linked within the Framework to provide multimedia simulation capabilities for hydrology and water quality processes: the Soil Water Assessment Tool (SWAT) predicts surface water and sediment runoff and associated contaminants; the Watershed Mercury Model (WMM) predicts mercury runoff and loading to streams; the Water quality Analysis and Simulation Program (WASP) predicts water quality within the stream channel; the Habitat Suitability Index (HSI) model scores physicochemical habitat quality for individual fish species; and the Bioaccumulation and Aquatic System Simulator (BASS) predicts fish growth, population dynamics and bioaccumulation

  12. Evidence for multiple stressor interactions and effects on coral reefs.

    Science.gov (United States)

    Ban, Stephen S; Graham, Nicholas A J; Connolly, Sean R

    2014-03-01

    Concern is growing about the potential effects of interacting multiple stressors, especially as the global climate changes. We provide a comprehensive review of multiple stressor interactions in coral reef ecosystems, which are widely considered to be one of the most sensitive ecosystems to global change. First, we synthesized coral reef studies that examined interactions of two or more stressors, highlighting stressor interactions (where one stressor directly influences another) and potentially synergistic effects on response variables (where two stressors interact to produce an effect that is greater than purely additive). For stressor-stressor interactions, we found 176 studies that examined at least 2 of the 13 stressors of interest. Applying network analysis to analyze relationships between stressors, we found that pathogens were exacerbated by more costressors than any other stressor, with ca. 78% of studies reporting an enhancing effect by another stressor. Sedimentation, storms, and water temperature directly affected the largest number of other stressors. Pathogens, nutrients, and crown-of-thorns starfish were the most-influenced stressors. We found 187 studies that examined the effects of two or more stressors on a third dependent variable. The interaction of irradiance and temperature on corals has been the subject of more research (62 studies, 33% of the total) than any other combination of stressors, with many studies reporting a synergistic effect on coral symbiont photosynthetic performance (n = 19). Second, we performed a quantitative meta-analysis of existing literature on this most-studied interaction (irradiance and temperature). We found that the mean effect size of combined treatments was statistically indistinguishable from a purely additive interaction, although it should be noted that the sample size was relatively small (n = 26). Overall, although in aggregate a large body of literature examines stressor effects on coral reefs and coral

  13. Work stressors and partner social undermining: Comparing negative affect and psychological detachment as mechanisms.

    Science.gov (United States)

    Meier, Laurenz L; Cho, Eunae

    2018-05-14

    With the mounting evidence that employees' work experiences spill over into the family domain and cross over to family members, it is important to understand the underlying mechanism through which work experiences affect the family domain and what factors may alleviate the adverse impact of work stress. Expanding previous research that mainly focused on the affect-based mechanism (negative affect), the present research investigated a resource-based mechanism (psychological detachment from work) in the relationship linking two work stressors (high workload and workplace incivility) with social undermining toward the partner at home. We also explored the relative strength of the mediating effects of the two mechanisms. In addition, we tested whether relationship satisfaction moderates the proposed effect of detachment on partner undermining. We tested these research questions using two studies with differing designs: a five-wave longitudinal study (N = 470) and a multisource study (N = 131). The results suggest that stressful work experiences affect the family domain via lack of detachment as well as negative affect, that the two pathways have comparable strength, and that high relationship satisfaction mitigates the negative effect of lack of detachment on partner undermining. In sum, this research extends the spillover-crossover model by establishing that poor psychological detachment from work during leisure time is an additional mechanism that links work and family. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  14. Neotropical Amphibian Declines Affect Stream Ecosystem Properties

    Science.gov (United States)

    Connelly, S.; Pringle, C. M.; Bixby, R. J.; Whiles, M. R.; Lips, K. R.; Brenes, R.; Colon-Gaud, J. C.; Kilham, S.; Hunte-Brown, M.

    2005-05-01

    Global declines of amphibians are well documented, yet effects of these dramatic losses on ecosystem structure and function are poorly understood. As part of a larger collaborative project, we compared two upland Panamanian streams. Both streams are biologically and geologically similar; however, one stream (Fortuna) has recently experienced almost complete extirpation of stream-dwelling frogs, while the other (Cope) still has intact populations. We experimentally excluded tadpoles from localized areas in each stream. We then compared chlorophyll a, algal community composition, ash-free dry mass (AFDM), inorganic matter, and insect assemblages in control and exclusion areas. Additionally, we sampled the natural substrate of both streams monthly for chlorophyll a, algal community composition, AFDM, and inorganic matter. At Cope, chlorophyll a, AFDM, and inorganic matter were greater in areas where tadpoles were excluded than in their presence. Numbers of dominant algal species (e.g., Nupela praecipua and Eunotia siolii) were greater in the exclusion versus control treatments. Monthly sampling of natural substrate indicated higher chlorophyll a and AFDM at Cope compared to Fortuna. Our data suggest that stream-dwelling anuran larvae have significant impacts on algal communities. These results also have implications for predicting the relevance of short-term experimental manipulations to long-term, whole-stream processes.

  15. The Range and Impact of Postmigration Stressors During Treatment of Trauma-Affected Refugees

    DEFF Research Database (Denmark)

    Bruhn, Maja; Rees, Susan; Mohsin, Mohammed

    2018-01-01

    . Postmigration stressors were deemed to impact on 39.1% of treatment sessions with medical personnel. Issues related to work, finances, and family were the most frequently identified stressors. Postmigration stressors interfering with treatment were more common among male refugees, those living alone, those from...... for trauma-related mental distress. A total of 116 patients completed 6 months of multidisciplinary treatment. Clinician-rated postmigration stressors were registered at each session. Outcome measures were Harvard Trauma Questionnaire and Global Assessment of Functioning, function (GAF-F) and symptom...

  16. Rainfall changes affect the algae dominance in tank bromeliad ecosystems

    Science.gov (United States)

    Pires, Aliny Patricia Flauzino; Leal, Juliana da Silva; Peeters, Edwin T. H. M.

    2017-01-01

    Climate change and biodiversity loss have been reported as major disturbances in the biosphere which can trigger changes in the structure and functioning of natural ecosystems. Nonetheless, empirical studies demonstrating how both factors interact to affect shifts in aquatic ecosystems are still unexplored. Here, we experimentally test how changes in rainfall distribution and litter diversity affect the occurrence of the algae-dominated condition in tank bromeliad ecosystems. Tank bromeliads are miniature aquatic ecosystems shaped by the rainwater and allochthonous detritus accumulated in the bases of their leaves. Here, we demonstrated that changes in the rainfall distribution were able to reduce the chlorophyll-a concentration in the water of bromeliad tanks affecting significantly the occurrence of algae-dominated conditions. On the other hand, litter diversity did not affect the algae dominance irrespective to the rainfall scenario. We suggest that rainfall changes may compromise important self-reinforcing mechanisms responsible for maintaining high levels of algae on tank bromeliads ecosystems. We summarized these results into a theoretical model which suggests that tank bromeliads may show two different regimes, determined by the bromeliad ability in taking up nutrients from the water and by the total amount of light entering the tank. We concluded that predicted climate changes might promote regime shifts in tropical aquatic ecosystems by shaping their structure and the relative importance of other regulating factors. PMID:28422988

  17. Identification of Stressors that Affect White Spot Syndrome Virus (WSSV) Infection and Outbreak in Pond Cultured Penaeus monodon

    NARCIS (Netherlands)

    Tendencia Alapide, E.; Verreth, J.A.J.

    2011-01-01

    White spot syndrome virus (WSSV) has been a big problem to the worldwide shrimp industry. Exposure to stressors related to physicochemical water parameters affect WSSV infection but not all WSSV infections result in outbreaks. This paper describes a detailed monitoring of important physicochemical

  18. Affective and physiological response to a novel parent-adolescent conflict stressor.

    Science.gov (United States)

    Cook, Emily C; Duncan, Orianna; Fernandez, Mary Ellen; Mercier, Bryan; Windrow, Jason; Stroud, Laura R

    2018-03-20

    Few laboratory paradigms exist that expose adolescents to conflict that might commonly be experienced in parent-adolescent relationships. Given the continued importance of parent-adolescent relationships on adolescent development, as well as the changing expectations in these relationships, we examined the effect of a novel parent-adolescent conflict paradigm on physiological and affective response in a sample of 52 adolescents. The parent-adolescent conflict stressor (PACS) involved adolescent participants (50% girls; M = 14.75, SD = 0.88) watching a 12-minute scripted video that asked youth to imagine that they were the teenager in the video, which consisted of parent and adolescent actors having discussions about conflict in their relationship and solving this conflict in either a positive, typical, or hostile manner. Cortisol, alpha amylase, and self-report of negative and positive affect were collected at baseline, following the video, and during a recovery period. Heart rate also was taken continuously while adolescents watched the videos. Hierarchical linear modeling (HLM) analyses indicated significant linear change in alpha amylase and linear and quadratic change in negative affect to the PACS. There also was a significant linear and quadratic change in heart rate during the portion of the video where teens and parents discussed issues of personal responsibility. The PACS marks a preliminary but important first step in developing a parent-adolescent conflict paradigm that can be used across studies to understand the impact of parent-adolescent conflict on affective and physiological markers associated with stress response.

  19. Stressor experience negatively affects life satisfaction in adolescents: the positive role of sense of coherence.

    Science.gov (United States)

    Moksnes, Unni K; Haugan, G

    2015-10-01

    The aim of the present study was to investigate the association between different normative stressors, sense of coherence and life satisfaction separately for gender in Norwegian adolescents. The interaction effect of stress by sense of coherence in relation to life satisfaction was also investigated. The data are based on a cross-sectional sample of 1239 adolescents (13-18 years) from public elementary and secondary schools in Central Norway. Hierarchical multiple regression analysis was used to evaluate the association between stressors, sense of coherence and life satisfaction, separately for gender. The results showed significant differences between genders, where boys reported higher scores than girls on sense of coherence and life satisfaction, whereas girls scored higher than boys on five of seven stressor domains. All stressors were significantly and inversely associated with life satisfaction in both genders; however, all associations were stronger for girls compared to boys. Sense of coherence showed a significant strong and positive association with life satisfaction, controlled for age and each individual stressor. A significant although weak interaction effect of stress related to romantic relationships by sense of coherence was found in association with life satisfaction for boys; the other interaction effects were nonsignificant in both genders. The results give support for a significant unique role of stressor experience and sense of coherence in relation to life satisfaction in both genders during adolescence, where the associations were especially strong in girls.

  20. Toward a conceptual approach for assessing risks from chemical mixtures and other stressors to coastal ecosystem services

    DEFF Research Database (Denmark)

    Syberg, Kristian; Backhaus, Thomas; Banta, Gary Thomas

    2017-01-01

    in Costa Rica) are provided; one focuses on chemicals that affect human food supply and the other addresses pesticide runoff and trade-offs among ES. The 2 cases are used to highlight challenges of such risk assessments, including use of standardized versus ES-relevant test species, data completeness......, translate impacts into ES units; step F, assess cumulative risk in ES units; step G, rank stressors based on their contribution to adverse effects on ES; and step H, implement regulation and management as appropriate and necessary. Two illustrative case studies (Swedish coastal waters and a coastal lagoon......, and trade-offs among ES. Lessons learned from the 2 case studies are discussed in relation to environmental risk assessment and management of chemical mixtures....

  1. Identifying the interacting roles of stressors in driving the global loss of canopy-forming to mat-forming algae in marine ecosystems.

    Science.gov (United States)

    Strain, Elisabeth M A; Thomson, Russell J; Micheli, Fiorenza; Mancuso, Francesco P; Airoldi, Laura

    2014-11-01

    Identifying the type and strength of interactions between local anthropogenic and other stressors can help to set achievable management targets for degraded marine ecosystems and support their resilience by identifying local actions. We undertook a meta-analysis, using data from 118 studies to test the hypothesis that ongoing global declines in the dominant habitat along temperate rocky coastlines, forests of canopy-forming algae and/or their replacement by mat-forming algae are driven by the nonadditive interactions between local anthropogenic stressors that can be addressed through management actions (fishing, heavy metal pollution, nutrient enrichment and high sediment loads) and other stressors (presence of competitors or grazers, removal of canopy algae, limiting or excessive light, low or high salinity, increasing temperature, high wave exposure and high UV or CO2 ), not as easily amenable to management actions. In general, the cumulative effects of local anthropogenic and other stressors had negative effects on the growth and survival of canopy-forming algae. Conversely, the growth or survival of mat-forming algae was either unaffected or significantly enhanced by the same pairs of stressors. Contrary to our predictions, the majority of interactions between stressors were additive. There were however synergistic interactions between nutrient enrichment and heavy metals, the presence of competitors, low light and increasing temperature, leading to amplified negative effects on canopy-forming algae. There were also synergistic interactions between nutrient enrichment and increasing CO2 and temperature leading to amplified positive effects on mat-forming algae. Our review of the current literature shows that management of nutrient levels, rather than fishing, heavy metal pollution or high sediment loads, would provide the greatest opportunity for preventing the shift from canopy to mat-forming algae, particularly in enclosed bays or estuaries because of the

  2. The Paradoxical Roles of Climate Stressors on Disturbance and Recovery of Coral Reef Ecosystems

    Science.gov (United States)

    Manfrino, C.; Foster, G.; Camp, E.

    2013-05-01

    The geographic isolation, absence of significant anthropogenic impacts, compressed spatial scale, and habitat diversity of Little Cayman combine to make it a natural laboratory for elucidating the dualistic impacts of various climatic events. These events both impart ecosystem disturbances and aid in the subsequent recovery of coral reef habitats. Within the isolated microcosm of Little Cayman the environmental factors commonly associated with coral stress, mortality, resilience and recovery hinted at by regional-scale observations can be more clearly observed. The primary thrust of this study is to reveal the under-pinning biophysical and hydrologic factors pertinent to reef resilience and to better understand the various roles played by climatic disturbances that have led to the rapid recovery of corals at Little Cayman following a spate of high temperature anomalies. Six closely-spaced high-temperature events were recorded in the Caribbean between the years of 1987 and 2009. Of these, only the 1998 global ENSO event, with well-documented levels of elevated SST, reduced cloud cover and surface water texture with concomittant increases in UV and irradiance and reduced water velocity, resulted in significant mortality at Little Cayman. Following this event, island-wide live coral cover decreased by 40%, from 26% to 14%. Annual monitoring of live coral cover following the 1998 ENSO event revealed no significant recovery of live coral cover until 2009, at which point there was a rapid rebound to pre-disturbance levels by 2011. Such a protracted step-change in coral recovery is indicative of one or more episodic events. The proposed scenario is that the numerous thermal stress events damaged the photo-system of the zooxanthellae, limiting the scope for growth and recovery as the metabolic budgets of corals were diverted to cellular repair. It is posited that the rapid cooling effect of frequent Tropical Storms and Hurricanes between 2002 - 2008, coupled with the

  3. Hexabromocyclododecane affects benthic-pelagic coupling in an experimental ecosystem

    International Nuclear Information System (INIS)

    Bradshaw, Clare; Näslund, Johan; Hansen, Joakim; Kozlowsky-Suzuki, Betina; Sundström, Bo; Gustafsson, Kerstin

    2015-01-01

    Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant and a recognized PBT chemical. However, little is known about its effects on coastal species, and even less on ecosystem effects. We investigated the dose–response effects of HBCDD over 8 months in 1000 L experimental mesocosms assembled from coastal Baltic Sea ecosystem components. HBCDD was added via spiked plankton material and a range of structural and functional endpoints were measured during the experiment. Increasing HBCDD concentration decreased the biomass of large Macoma balthica, resulting in a decreased recirculation of nutrients to the water. Changes in plankton communities were also observed, either due to direct toxic HBCDD effects or indirect via changes in benthic-pelagic coupling of nutrients. Such complex ecosystem responses can only be quantified and understood by using realistic experimental set-ups, and including knowledge of system-specific ecological interactions. This is the first study of HBCDD effects on ecosystem level. - Graphical abstract: HBCDD caused direct effects on the population structure of sediment-dwelling Macoma balthica and on the plankton community. Indirect HBCDD effects via reduced nutrient remineralization by M. balthica affected nutrient levels in the water, likely leading to additional changes in plankton community structure. Seasonal effects were large and affected the whole system including nutrient dynamics as well as plankton community structure. Display Omitted - Highlights: • HBCDD caused effects on benthic population structure and ecosystem function. • Large seasonal effects highlight the importance of using relevant experimental conditions. • A realistic exposure pathway was applied by using HBCDD enriched plankton material. • This is the first study of HBCDD effects on ecosystem level, coupling benthic and pelagic communities. - HBCDD has a dose-dependent effect on benthic-pelagic coupling.

  4. Acculturative stressor and meaning of life as predictors of negative affect in acculturation: a cross-cultural comparative study between Chinese international students in Australia and Hong Kong.

    Science.gov (United States)

    Pan, Jia-Yan; Wong, Daniel Fu Keung; Joubert, Lynette; Chan, Cecilia Lai Wan

    2007-09-01

    The purpose of the present study was to compare the predictive effects of acculturative stressor and meaning of life on negative affect in the process of acculturation between Chinese international students in Australia and Hong Kong. Four hundred mainland Chinese students studying at six universities in Hong Kong and 227 Chinese international students studying at the University of Melbourne in Australia completed a questionnaire that included measures of acculturative stressor, meaning of life, negative affect and demographic information. The Australian sample was found to have a higher level of acculturative stressor and negative affect than the Hong Kong sample. Acculturative stressor had a positive impact on negative affect in both samples, but the impact of different domains of acculturative stressor on negative affect varied between the two groups. Finally, meaning of life partially mediated the relationship between acculturative stressor and negative affect in the Hong Kong sample, but no such effect was found in the Australia sample. Acculturative stressor is a critical risk factor for negative affect in acculturation for Chinese international students in Australia and Hong Kong. Meaning of life acted as a protective factor that mitigated negative affect for mainland Chinese students in Hong Kong, but not for the Chinese international students in Australia. The theoretical and practical implications for resilience-based and meaning-oriented intervention for Chinese international students are discussed.

  5. Bidirectional, Temporal Associations of Sleep with Positive Events, Affect, and Stressors in Daily Life Across a Week.

    Science.gov (United States)

    Sin, Nancy L; Almeida, David M; Crain, Tori L; Kossek, Ellen Ernst; Berkman, Lisa F; Buxton, Orfeu M

    2017-06-01

    Sleep is intricately tied to emotional well-being, yet little is known about the reciprocal links between sleep and psychosocial experiences in the context of daily life. The aim of this study is to evaluate daily psychosocial experiences (positive and negative affect, positive events, and stressors) as predictors of same-night sleep quality and duration, in addition to the reversed associations of nightly sleep predicting next-day experiences. Daily experiences and self-reported sleep were assessed via telephone interviews for eight consecutive evenings in two replicate samples of US employees (131 higher-income professionals and 181 lower-income hourly workers). Multilevel models evaluated within-person associations of daily experiences with sleep quality and duration. Analyses controlled for demographics, insomnia symptoms, the previous day's experiences and sleep measures, and additional day-level covariates. Daily positive experiences were associated with improved as well as disrupted subsequent sleep. Specifically, positive events at home predicted better sleep quality in both samples, whereas greater positive affect was associated with shorter sleep duration among the higher-income professionals. Negative affect and stressors were unrelated to subsequent sleep. Results for the reversed direction revealed that better sleep quality (and, to a lesser degree, longer sleep duration) predicted emotional well-being and lower odds of encountering stressors on the following day. Given the reciprocal relationships between sleep and daily experiences, efforts to improve well-being in daily life should reflect the importance of sleep.

  6. How Do Self-Efficacy, Contextual Variables and Stressors Affect Teacher Burnout in an EFL Context?

    Science.gov (United States)

    Khani, Reza; Mirzaee, Alireza

    2015-01-01

    This study was an attempt to investigate the relationships among stressors, contextual variables, self-efficacy and teacher burnout in Iran as an EFL (English as a Foreign Language) context. A battery of questionnaires was administered to 216 English language teachers of private language institutes. Using Amos version 20, structural equation…

  7. Shifts of community composition and population density substantially affect ecosystem function despite invariant richness

    NARCIS (Netherlands)

    Spaak, Jurg W.; Baert, Jan M.; Baird, Donald J.; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R.; Brink, van den Paul J.; Laender, De Frederik

    2017-01-01

    There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community

  8. Affective temperament, social support and stressors at work as the predictors of life and job satisfaction among doctors and psychologists

    Directory of Open Access Journals (Sweden)

    Jaredić Biljana

    2017-01-01

    Full Text Available Background/Aim. Affective temperament, social support and work-related stresors belong to the group of life and job satisfaction indicators. The aim of this research was to examine predictive roles of the basic affective temperament traits, social support and work-related stressors in the feeling of job and life satisfaction among doctors and psychologists. Methods. The sample consisted of 203 individuals out of whom there were 28% male and 72% female doctors (61% and psychologists (39%, 25–65 years old (39.08 ± 9.29, from the two university towns in Serbia. The set of questionnaires included Serbian version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego – autoquestionnaire version (TEMPS-A, Satisfaction with Life scale, Job Satisfaction Survey, short Interpersonal Support Evaluation List, and Source of Stress at Work Scale (IRSa for estimating the frequency of stressors at work. Results. According to the existing norms our examinees are satisfied with their life, but considerably less satisfied with their work, specially with pay and benefits, while they are most satisfied with nature of work itself and social relations with co-workers and supervisors. Our results show that depressive and hyperthymic, and to some extent cyclothymic temperament traits of the affective temperament significantly predict 21% of life satisfaction variance. Situational factors, such as stressors at work and social support, are important in predicting job satisfaction (58% of variance with no significant contribution of temperament traits. The analysis did not point out any significant relation of sex, occupation, and age with life and job satisfaction. Conclusions. Affective temperaments can be regarded as predictors of life satisfaction, but in order to better predict satisfaction the aspects of wider social surrounding and sources of stressors at work must be taken in consideration. Future studies should consider other indicators of life

  9. Why employees with higher challenging appraisals style are more affectively engaged at work? The role of challenging stressors: a moderated mediation model.

    Science.gov (United States)

    Lin, Shin-Huei; Wu, Chia-Huei; Chen, Mei-Yen; Chen, Lung Hung

    2014-10-01

    Challenging stressors have been positively linked to various work outcomes. However, the role of individual differences in stress appraisal in shaping the function of challenging stressors and work outcomes has been rarely discussed. Drawing on the individual differences perspective, the authors propose that employees higher in challenge appraisal are more likely to have challenging stressors and are more responsive to such stressors to have a higher positive affect at work. Results obtained from 117 employees supported the hypotheses. The results indicated that challenge appraisal is positively related to challenging stressors. In addition, challenging stressors has a positive association with positive affect at work when challenge appraisal is high but has a null association when challenge appraisal is low. The findings suggest that challenging stressors does not necessarily bring positive work outcomes as suggested in past studies and highlight the importance of considering dispositional tendency in stress appraisal when looking into the function of challenging stressors and work outcomes. © 2014 International Union of Psychological Science.

  10. An integrated ecological modeling system for assessing impacts of multiple stressors on stream and riverine ecosystem services within river basins

    Data.gov (United States)

    U.S. Environmental Protection Agency — We demonstrate a novel, spatially explicit assessment of the current condition of aquatic ecosystem services, with limited sensitivity analysis for the atmospheric...

  11. How sulfate-rich mine drainage affected aquatic ecosystem degradation in northeastern China, and potential ecological risk.

    Science.gov (United States)

    Zhao, Qian; Guo, Fen; Zhang, Yuan; Ma, Shuqin; Jia, Xiaobo; Meng, Wei

    2017-12-31

    Mining activity is an increasingly important stressor for freshwater ecosystems. However, the mechanism on how sulfate-rich mine drainage affects freshwater ecosystems is largely unknown, and its potential ecological risk has not been assessed so far. During 2009-2016, water and macroinvertebrate samples from 405 sample sites were collected along the mine drainage gradient from circum-neutral to alkaline waters in Hun-Tai River, Northeastern China. Results of linear regressions showed that sulfate-rich mine drainage was significantly positively correlated with the constituents typically derived from rock weathering (Ca 2+ , Mg 2+ and HCO 3 - +CO 3 2- ); the diversity of intolerant stream macroinvertebrates exhibited a steep decline along the gradient of sulfate-rich mine drainage. Meanwhile, stressor-response relationships between sulfate-rich mine drainage and macroinvertebrate communities were explored by two complementary statistical approaches in tandem (Threshold Indicator Taxa Analysis and the field-based method developed by USEPA). Results revealed that once stream sulfate concentrations in mine drainage exceeded 35mg/L, significant decline in the abundance of intolerant macroinvertebrate taxa occurred. An assessment of ecological risk posed by sulfate-rich mine drainage was conducted based on a tiered approach consisting of simple deterministic method (Hazard Quotient, HQ) to probabilistic method (Joint Probability Curve, JPC). Results indicated that sulfate-rich mine drainage posed a potential risk, and 64.62-84.88% of surface waters in Hun-Tai River exist serious risk while 5% threshold (HC 05 ) and 1% threshold (HC 01 ) were set up to protect macroinvertebrates, respectively. This study provided us a better understanding on the impacts of sulfate-rich mine drainage on freshwater ecosystems, and it would be helpful for future catchment management to protect streams from mining activity. Copyright © 2017. Published by Elsevier B.V.

  12. Restoration of Degraded Salt Affected Lands to Productive Forest Ecosystem

    Science.gov (United States)

    Singh, Yash; Singh, Gurbachan; Singh, Bajrang; Cerdà, Artemi

    2017-04-01

    Soil system determines the fluxes of energy and matter in the Earth and is the source of goods, services and resources to the humankind (Keesstra et al., 2012; Brevik et al., 2015; Keesstra et al., 2016). To restore and rehabilitate the soil system is a key strategy to recover the services the soils offers (Celentano et al., 2016; Galati et al., 2016; Parras-Alcantara et al., 2016). Transformation of degraded sodic lands in biodiversity rich productive forest ecosystem is a challenging task before the researchers all over the world. The soils of the degraded sites remain almost unfavorable for the normal growth, development and multiplication of organisms; all our attempts tend to alleviate the soil constraints. Land degradation due to presence of salts in the soil is an alarming threat to agricultural productivity and sustainability, particularly in arid and semiarid regions of the world (Tanji, 1990; Qadir et al., 2006). According to the FAO Land and Nutrition Management Service (2008), over 6% of the world's lands are affected by salinity, which accounts for more than 800 million ha in 100 countries. This is due to natural causes, extensive utilization of land (Egamberdieva et al., 2008), poor drainage systems and limited availability of irrigation water which causes salinization in many irrigated soils (Town et al., 2008).In India, about 6.73 million ha are salt affected which spread in 194 districts out of 584 districts in India and represents 2.1% of the geographical area of the country (Mandal et al., 2009).Out of these, 2.8 million ha are sodic in nature and primarily occurring in the Indo-Gangetic alluvial plains. These lands are degraded in structural, chemical, nutritional, hydrological and microbiological characteristics. The reclamation of salt affected soils with chemical amendments like gypsum and phospho-gypsum are in practice for the cultivation field crops under agricultural production. Forest development on such lands although takes considerable

  13. Soil CO2 dynamics and fluxes as affected by tree harvest in an experimental sand ecosystem.

    Science.gov (United States)

    C.K. Keller; T.M. White; R. O' Brien; J.L. Smith

    2006-01-01

    Soil CO2 production is a key process in ecosystem C exchange, and global change predictions require understanding of how ecosystem disturbance affects this process. We monitored CO2 levels in soil gas and as bicarbonate in drainage from an experimental red pine ecosystem, for 1 year before and 3 years after its aboveground...

  14. Chemical and non-chemical stressors affecting childhood obesity: a systematic scoping review

    Science.gov (United States)

    Childhood obesity in the United States has doubled over the last three decades and currently affects 17% of children and adolescents. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous che...

  15. A quality improvement study on avoidable stressors and countermeasures affecting surgical motor performance and learning.

    Science.gov (United States)

    Conrad, Claudius; Konuk, Yusuf; Werner, Paul D; Cao, Caroline G; Warshaw, Andrew L; Rattner, David W; Stangenberg, Lars; Ott, Harald C; Jones, Daniel B; Miller, Diane L; Gee, Denise W

    2012-06-01

    To explore how the 2 most important components of surgical performance--speed and accuracy-are influenced by different forms of stress and what the impact of music is on these factors. On the basis of a recently published pilot study on surgical experts, we designed an experiment examining the effects of auditory stress, mental stress, and music on surgical performance and learning and then correlated the data psychometric measures to the role of music in a novice surgeon's life. Thirty-one surgeons were recruited for a crossover study. Surgeons were randomized to 4 simple standardized tasks to be performed on the SurgicalSIM VR laparoscopic simulator (Medical Education Technologies, Inc, Sarasota, FL), allowing exact tracking of speed and accuracy. Tasks were performed under a variety of conditions, including silence, dichotic music (auditory stress), defined classical music (auditory relaxation), and mental loading (mental arithmetic tasks). Tasks were performed twice to test for memory consolidation and to accommodate for baseline variability. Performance was correlated to the brief Musical Experience Questionnaire (MEQ). Mental loading influences performance with respect to accuracy, speed, and recall more negatively than does auditory stress. Defined classical music might lead to minimally worse performance initially but leads to significantly improved memory consolidation. Furthermore, psychologic testing of the volunteers suggests that surgeons with greater musical commitment, measured by the MEQ, perform worse under the mental loading condition. Mental distraction and auditory stress negatively affect specific components of surgical learning and performance. If used appropriately, classical music may positively affect surgical memory consolidation. It also may be possible to predict surgeons' performance and learning under stress through psychological tests on the role of music in a surgeon's life. Further investigation is necessary to determine the

  16. Management strategies of marine food resources under multiple stressors with particular reference of the Yellow Sea large marine ecosystem

    Directory of Open Access Journals (Sweden)

    Qisheng TANG

    2014-02-01

    Full Text Available In this study two main management strategies are discussed: one is to develop resource conservation-based capture fisheries, and the other is to develop environmentally friendly aquaculture. During the resource recovery period, the development of environmentally friendly aquaculture should be encouraged, especially in integrated multi-trophic aquaculture, which is adaptive, efficient and sustainable. For future development and better understanding the ecosystem, it is necessary to further strengthen basic research.

  17. Response of the rare biosphere to environmental stressors in a highly diverse ecosystem (Zodletone spring, OK, USA).

    Science.gov (United States)

    Coveley, Suzanne; Elshahed, Mostafa S; Youssef, Noha H

    2015-01-01

    Within highly diverse ecosystems, the majority of bacterial taxa are present in low abundance as members of the rare biosphere. The rationale for the occurrence and maintenance of the rare biosphere, and the putative ecological role(s) and dynamics of its members within a specific ecosystem is currently debated. We hypothesized that in highly diverse ecosystems, a fraction of the rare biosphere acts as a backup system that readily responds to environmental disturbances. We tested this hypothesis by subjecting sediments from Zodletone spring, a sulfide- and sulfur-rich spring in Southwestern OK, to incremental levels of salinity (1, 2, 3, 4, and 10% NaCl), or temperature (28°, 30°, 32°, and 70 °C), and traced the trajectories of rare members of the community in response to these manipulations using 16S rRNA gene analysis. Our results indicate that multiple rare bacterial taxa are promoted from rare to abundant members of the community following such manipulations and that, in general, the magnitude of such recruitment is directly proportional to the severity of the applied manipulation. Rare members that are phylogenetically distinct from abundant taxa in the original sample (unique rare biosphere) played a more important role in the microbial community response to environmental disturbances, compared to rare members that are phylogenetically similar to abundant taxa in the original sample (non-unique rare biosphere). The results emphasize the dynamic nature of the rare biosphere, and highlight its complexity and non-monolithic nature.

  18. Additive effects prevail: The response of biota to multiple stressors in an intensively monitored watershed.

    Science.gov (United States)

    Gieswein, Alexander; Hering, Daniel; Feld, Christian K

    2017-09-01

    Freshwater ecosystems are impacted by a range of stressors arising from diverse human-caused land and water uses. Identifying the relative importance of single stressors and understanding how multiple stressors interact and jointly affect biology is crucial for River Basin Management. This study addressed multiple human-induced stressors and their effects on the aquatic flora and fauna based on data from standard WFD monitoring schemes. For altogether 1095 sites within a mountainous catchment, we used 12 stressor variables covering three different stressor groups: riparian land use, physical habitat quality and nutrient enrichment. Twenty-one biological metrics calculated from taxa lists of three organism groups (fish, benthic invertebrates and aquatic macrophytes) served as response variables. Stressor and response variables were subjected to Boosted Regression Tree (BRT) analysis to identify stressor hierarchy and stressor interactions and subsequently to Generalised Linear Regression Modelling (GLM) to quantify the stressors standardised effect size. Our results show that riverine habitat degradation was the dominant stressor group for the river fauna, notably the bed physical habitat structure. Overall, the explained variation in benthic invertebrate metrics was higher than it was in fish and macrophyte metrics. In particular, general integrative (aggregate) metrics such as % Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa performed better than ecological traits (e.g. % feeding types). Overall, additive stressor effects dominated, while significant and meaningful stressor interactions were generally rare and weak. We concluded that given the type of stressor and ecological response variables addressed in this study, river basin managers do not need to bother much about complex stressor interactions, but can focus on the prevailing stressors according to the hierarchy identified. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. A Systems Approach to the Estimation of Ecosystem and Human Health Stressors in Air, Land and Water

    Science.gov (United States)

    Cooter, E. J.; Dennis, R. L.; Bash, J. O.

    2013-12-01

    Nitrogen (N) and sulfur oxides (SOx) in air, land and water media are parts of tightly coupled geophysical systems resulting in multiple routes for human and ecosystem exposure. For instance, excess forms of total reactive N in water can lead to harmful algal blooms, with the depletion of oxygen and adverse impacts to aquatic ecosystem productivity in coastal estuaries. Acidic deposition can result in lost forest productivity for terrestrial ecosystem and impacts to trout and other fishery resources in inland waters. Human pulmonary health can be impaired when N and SOx in the atmosphere lead to the generation of ozone and particulate matter (PM). Atmospheric N deposition can also contribute to eutrophication of drinking water sources. The U.S. Environmental Protection Agency (USEPA) Office of Research and Development (ORD) has embarked on the development of a multi-media 'one environment' systems approach to these issues to help develop management decisions that create win-win policies. The purpose of this project is to develop a 'one environment' set of models that can inform protection of ecosystems and human health in both the current state and under future climate scenarios. The research framework focuses on three interrelated themes; coupling air quality with land use and agricultural land management, connecting the hydrosphere (i.e., coupling meteorology and hydrology) and linking the air/land/hydrosphere with ecosystem models and benefits models. We will present an overall modeling framework and then move to the presentation of on-going research results related to direct linkage of air quality with land use and agricultural land management. A modeling interface system has been developed that facilitates the simulation of field-scale agricultural land management decisions over a gridded domain at multiple grid resolutions for the Contiguous United States (CONUS) using a modified version of the USDA EPIC (Environmental Policy Integrated Climate) model. EPIC

  20. Ecosystem Warming Affects CO2 Flux in an Agricultural Soil

    Science.gov (United States)

    Global warming seems likely based on present-day climate predictions. Our objective was to characterize and quantify the interactive effects of ecosystem warming (i.e., canopy temperature, TS), soil moisture content ('S) and microbial biomass (BM: bacteria, fungi) on the intra-row soil CO2 flux (FS)...

  1. Multiple Stressors and Ecological Complexity Require A New Approach to Coral Reef Research

    Directory of Open Access Journals (Sweden)

    Linwood Hagan Pendleton

    2016-03-01

    Full Text Available Ocean acidification, climate change, and other environmental stressors threaten coral reef ecosystems and the people who depend upon them. New science reveals that these multiple stressors interact and may affect a multitude of physiological and ecological processes in complex ways. The interaction of multiple stressors and ecological complexity may mean that the negative effects on coral reef ecosystems will happen sooner and be more severe than previously thought. Yet, most research on the effects of global change on coral reefs focus on one or few stressors and pathways or outcomes (e.g. bleaching. Based on a critical review of the literature, we call for a regionally targeted strategy of mesocosm-level research that addresses this complexity and provides more realistic projections about coral reef impacts in the face of global environmental change. We believe similar approaches are needed for other ecosystems that face global environmental change.

  2. Host genetics affect microbial ecosystems via host immunity.

    Science.gov (United States)

    El Kafsi, Hela; Gorochov, Guy; Larsen, Martin

    2016-10-01

    Genetic evolution of multicellular organisms has occurred in response to environmental challenges, including competition for nutrients, climate change, physical and chemical stressors, and pathogens. However, fitness of an organism is dependent not only on defense efficacy, but also on the ability to take advantage of symbiotic organisms. Indeed, microbes not only encompass pathogenicity, but also enable efficient nutrient uptake from diets nondegradable by the host itself. Moreover, microbes play important roles in the development of host immunity. Here we review associations between specific host genes and variance in microbiota composition and compare with interactions between microbes and host immunity. Recent genome-wide association studies reveal that symbiosis between host and microbiota is the exquisite result of genetic coevolution. Moreover, a subset of microbes from human and mouse microbiota have been identified to interact with humoral and cellular immunity. Interestingly, microbes associated with both host genetics and host immunity are taxonomically related. Most involved are Bifidobacterium, Lactobacillus, and Akkermansia, which are dually associated with both host immunity and host genetics. We conclude that future therapeutics targeting microbiota in the context of chronic inflammatory diseases need to consider both immune and genetic host features associated with microbiota homeostasis.

  3. Does stress affect the joints? Daily stressors, stress vulnerability, immune and HPA axis activity, and short-term disease and symptom fluctuations in rheumatoid arthritis.

    Science.gov (United States)

    Evers, Andrea W M; Verhoeven, Elisabeth W M; van Middendorp, Henriët; Sweep, Fred C G J; Kraaimaat, Floris W; Donders, A Rogier T; Eijsbouts, Agnes E; van Laarhoven, Antoinette I M; de Brouwer, Sabine J M; Wirken, Lieke; Radstake, Timothy R D J; van Riel, Piet L C M

    2014-09-01

    Both stressors and stress vulnerability factors together with immune and hypothalamus-pituitary-adrenal (HPA) axis activity components have been considered to contribute to disease fluctuations of chronic inflammatory diseases, such as rheumatoid arthritis (RA). The aim of the present study was to investigate whether daily stressors and worrying as stress vulnerability factor as well as immune and HPA axis activity markers predict short-term disease activity and symptom fluctuations in patients with RA. In a prospective design, daily stressors, worrying, HPA axis (cortisol) and immune system (interleukin (IL)-1β, IL-6, IL-8, interferon (IFN)-γ, tumour necrosis factor α) markers, clinical and self-reported disease activity (disease activity score in 28 joints, RA disease activity index), and physical symptoms of pain and fatigue were monitored monthly during 6 months in 80 RA patients. Multilevel modelling indicated that daily stressors predicted increased fatigue in the next month and that worrying predicted increased self-reported disease activity, swollen joint count and pain in the next month. In addition, specific cytokines of IL-1β and IFN-γ predicted increased fatigue 1 month later. Overall, relationships remained relatively unchanged after controlling for medication use, disease duration and demographic variables. No evidence was found for immune and HPA axis activity markers as mediators of the stress-disease relationship. Daily stressors and the stress-vulnerability factor worrying predict indicators of the short-term course of RA disease activity and fatigue and pain, while specific cytokines predict short-term fluctuations of fatigue. These stress-related variables and immune markers seem to affect different aspects of disease activity or symptom fluctuations independently in RA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    International Nuclear Information System (INIS)

    Marek, Michal V.; Janous, Dalibor; Taufarova, Klara; Havrankova, Katerina; Pavelka, Marian; Kaplan, Veroslav; Markova, Irena

    2011-01-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. - Highlights: → Highest carbon sequestration potential in evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). → The final carbon gain of the grassland was negative (massive ecosystem respiration). → Climate is important factor of net primary productivity. → Carbon uptake is strongly affected by the ontogeny and a production strategy of ecosystem. - Identification of the apparent differences in the carbon storage by different ecosystem types.

  5. Stressors and reactions to stressors among university students.

    Science.gov (United States)

    Hamaideh, Shaher H

    2011-01-01

    University students are prone to stressors due to the transitional nature of university life. High levels of stress are believed to affect students' health as well as their academic performance. The aims of this study were to identify stressors and reactions to stressors among university students, and to examine the correlations between student stressors and study variables. A correlational descriptive design was used. Student-life Stress Inventory (SSI) was used to measure the stressors and reactions to stressors. Stratified random sampling was employed to recruit participants. The final sample consisted of 877 participants (students). s indicated that the highest group of stressors experienced by students were 'self-imposed' stressors followed by 'pressures'. Cognitive responses were found to be the highest responses to stressors experienced by students. Negative correlations were found with student's perception of health, and father's and mother's level of education. This study revealed that stressors among university students come from 'self-imposed' stressors and 'pressures'. Stress management, assertiveness skills, time management and counselling sessions will be effective in reducing stress experienced by students.

  6. From global to regional and back again: common climate stressors of marine ecosystems relevant for adaptation across five ocean warming hotspots.

    Science.gov (United States)

    Popova, Ekaterina; Yool, Andrew; Byfield, Valborg; Cochrane, Kevern; Coward, Andrew C; Salim, Shyam S; Gasalla, Maria A; Henson, Stephanie A; Hobday, Alistair J; Pecl, Gretta T; Sauer, Warwick H; Roberts, Michael J

    2016-06-01

    Ocean warming 'hotspots' are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal-marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high-resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenic CO2 -driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature-defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change in SST is not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future

  7. Does microbial biomass affect pelagic ecosystem efficiency? An experimental study.

    Science.gov (United States)

    Wehr, J D; Le, J; Campbell, L

    1994-01-01

    Bacteria and other microorganisms in the pelagic zone participate in the recycling of organic matter and nutrients within the water column. The microbial loop is thought to enhance ecosystem efficiency through rapid recycling and reduced sinking rates, thus reducing the loss of nutrients contained in organisms remaining within the photic zone. We conducted experiments with lake communities in 5400-liter mesocosms, and measured the flux of materials and nutrients out of the water column. A factorial design manipulated 8 nutrient treatments: 4 phosphorus levels × 2 nitrogen levels. Total sedimentation rates were greatest in high-N mesocosms; within N-surplus communities, [Symbol: see text]1 µM P resulted in 50% increase in total particulate losses. P additions without added N had small effects on nutrient losses from the photic zone; +2 µM P tanks received 334 mg P per tank, yet after 14 days lost only 69 mg more particulate-P than did control communities. Nutrient treatments resulted in marked differences in phytoplankton biomass (twofold N effect, fivefold P effect in +N mesocosms only), bacterioplankton densities (twofold N-effect, twofold P effects in -N and +N mesocosms), and the relative importance of autotrophic picoplankton (maximum in high NY mesocosms). Multiple regression analysis found that of 8 plankton and water chemistry variables, the ratio of autotrophic picoplankton to total phytoplankton (measured as chlorophyll α) explained the largest portion of the total variation in sedimentation loss rates (65% of P-flux, 57% of N-flux, 26% of total flux). In each case, systems with greater relative importance of autotrophic picoplankton had significantly reduced loss rates. In contrast, greater numbers of planktonic bacteria were associated with increased sedimentation rates and lower system efficiency. We suggest that different microbial components may have contrasting effects on the presumed enhanced efficiency provided by the microbial loop.

  8. Stressful Life Events and Daily Stressors Affect Awakening Cortisol Level in Midlife Mothers of Individuals with Autism Spectrum Disorders

    Science.gov (United States)

    Wong, Jen D.; Seltzer, Marsha Mailick; Greenberg, Jan S.; Hong, Jinkuk; Almeida, David M.; Coe, Christopher L.

    2012-01-01

    Objectives The current study examines the awakening cortisol level in midlife mothers (M=51.4 years old, SD=8.4) of individuals (M=22.1 years old, SD=7.1) with autism spectrum disorders (ASD) under stressful conditions that are not specific to the son or daughter's ASD symptoms. Methods In addition to completing a set of questionnaires and in-home interviews, 82 mothers from the Adolescents and Adults with Autism Study (AAA) participated in a Daily Diary Study. Results Findings from the multilevel models indicated that mothers who previously were exposed to no negative life events in the previous period had an increased awakening cortisol level on days following a greater number and more severe stressors, a normative stress response. In contrast, we observed a flatter cortisol level of daily stressors in mothers who experienced a greater number of negative life events in the previous period. Conclusion These findings highlight the sustained toll that global and everyday stressors have on awakening cortisol level of midlife and aging mothers of individuals with ASD. PMID:22640177

  9. Maternal deprivation affects the neuromuscular protein profile of the rat colon in response to an acute stressor later in life.

    Science.gov (United States)

    Lopes, Luísa V; Marvin-Guy, Laure F; Fuerholz, Andreas; Affolter, Michael; Ramadan, Ziad; Kussmann, Martin; Fay, Laurent B; Bergonzelli, Gabriela E

    2008-04-30

    Early life stress as neonatal maternal deprivation (MD) predisposes rats to alter gut functions in response to acute psychological stressors in adulthood, mimicking features of irritable bowel syndrome (IBS). We applied proteomics to investigate whether MD permanently changes the protein profile of the external colonic neuromuscular layer that may condition the molecular response to an acute stressor later in life. Male rat pups were separated 3 h/day from their mothers during the perinatal period and further submitted to water avoidance (WA) stress during adulthood. Proteins were extracted from the myenteric plexus-longitudinal muscle of control (C), WA and MD+WA rat colon, separated on 2D gels, and identified by mass spectrometry. MD amplified the WA-induced protein changes involved in muscle contractile function, suggesting that stress accumulation along life imbalances the muscle tone towards hypercontractility. Our results also propose a stress dependent regulation of gluconeogenesis. Secretogranin II - the secretoneurin precursor - was induced by MD. The presence of secretoneurin in myenteric ganglia may partially explain the stress-mediated modulation of gastrointestinal motility and/or mucosal inflammation previously described in MD rats. In conclusion, our findings suggest that neonatal stress alters the responses to acute stress in adulthood in intestinal smooth muscle and enteric neurons.

  10. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors.

    Science.gov (United States)

    Marek, Michal V; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, Irena

    2011-05-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Artificial Light at Night Affects Organism Flux across Ecosystem Boundaries and Drives Community Structure in the Recipient Ecosystem

    Directory of Open Access Journals (Sweden)

    Alessandro Manfrin

    2017-10-01

    Full Text Available Artificial light at night (ALAN is a widespread alteration of the natural environment that can affect the functioning of ecosystems. ALAN can change the movement patterns of freshwater animals that move into the adjacent riparian and terrestrial ecosystems, but the implications for local riparian consumers that rely on these subsidies are still unexplored. We conducted a 2-year field experiment to quantify changes of freshwater-terrestrial linkages by installing streetlights in a previously light-naïve riparian area adjacent to an agricultural drainage ditch. We compared the abundance and community composition of emerging aquatic insects, flying insects, and ground-dwelling arthropods with an unlit control site. Comparisons were made within and between years using two-way generalized least squares (GLS model and a BACI design (Before-After Control-Impact. Aquatic insect emergence, the proportion of flying insects that were aquatic in origin, and the total abundance of flying insects all increased in the ALAN-illuminated area. The abundance of several night-active ground-dwelling predators (Pachygnatha clercki, Trochosa sp., Opiliones increased under ALAN and their activity was extended into the day. Conversely, the abundance of nocturnal ground beetles (Carabidae decreased under ALAN. The changes in composition of riparian predator and scavenger communities suggest that the increase in aquatic-to-terrestrial subsidy flux may cascade through the riparian food web. The work is among the first studies to experimentally manipulate ALAN using a large-scale field experiment, and provides evidence that ALAN can affect processes that link adjacent ecosystems. Given the large number of streetlights that are installed along shorelines of freshwater bodies throughout the globe, the effects could be widespread and represent an underestimated source of impairment for both aquatic and riparian systems.

  12. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Science.gov (United States)

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  13. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Directory of Open Access Journals (Sweden)

    Pablo Rodríguez-Lozano

    Full Text Available Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1 leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2 triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel, conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

  14. Responses of stream microbes to multiple anthropogenic stressors in a mesocosm study.

    Science.gov (United States)

    Nuy, Julia K; Lange, Anja; Beermann, Arne J; Jensen, Manfred; Elbrecht, Vasco; Röhl, Oliver; Peršoh, Derek; Begerow, Dominik; Leese, Florian; Boenigk, Jens

    2018-08-15

    Stream ecosystems are affected by multiple anthropogenic stressors worldwide. Even though effects of many single stressors are comparatively well studied, the effects of multiple stressors are difficult to predict. In particular bacteria and protists, which are responsible for the majority of ecosystem respiration and element flows, are infrequently studied with respect to multiple stressors responses. We conducted a stream mesocosm experiment to characterize the responses of single and multiple stressors on microbiota. Two functionally important stream habitats, leaf litter and benthic phototrophic rock biofilms, were exposed to three stressors in a full factorial design: fine sediment deposition, increased chloride concentration (salinization) and reduced flow velocity. We analyzed the microbial composition in the two habitat types of the mesocosms using an amplicon sequencing approach. Community analysis on different taxonomic levels as well as principle component analyses (PCoAs) based on realtive abundances of operational taxonomic units (OTUs) showed treatment specific shifts in the eukaryotic biofilm community. Analysis of variance (ANOVA) revealed that Bacillariophyta responded positively salinity and sediment increase, while the relative read abundance of chlorophyte taxa decreased. The combined effects of multiple stressors were mainly antagonistic. Therefore, the community composition in multiply stressed environments resembled the composition of the unstressed control community in terms of OTU occurrence and relative abundances. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Synergistic interactions of biotic and abiotic environmental stressors on gene expression.

    Science.gov (United States)

    Altshuler, Ianina; McLeod, Anne M; Colbourne, John K; Yan, Norman D; Cristescu, Melania E

    2015-03-01

    Understanding the response of organisms to multiple stressors is critical for predicting if populations can adapt to rapid environmental change. Natural and anthropogenic stressors often interact, complicating general predictions. In this study, we examined the interactive and cumulative effects of two common environmental stressors, lowered calcium concentration, an anthropogenic stressor, and predator presence, a natural stressor, on the water flea Daphnia pulex. We analyzed expression changes of five genes involved in calcium homeostasis - cuticle proteins (Cutie, Icp2), calbindin (Calb), and calcium pump and channel (Serca and Ip3R) - using real-time quantitative PCR (RT-qPCR) in a full factorial experiment. We observed strong synergistic interactions between low calcium concentration and predator presence. While the Ip3R gene was not affected by the stressors, the other four genes were affected in their transcriptional levels by the combination of the stressors. Transcriptional patterns of genes that code for cuticle proteins (Cutie and Icp2) and a sarcoplasmic calcium pump (Serca) only responded to the combination of stressors, changing their relative expression levels in a synergistic response, while a calcium-binding protein (Calb) responded to low calcium stress and the combination of both stressors. The expression pattern of these genes (Cutie, Icp2, and Serca) were nonlinear, yet they were dose dependent across the calcium gradient. Multiple stressors can have complex, often unexpected effects on ecosystems. This study demonstrates that the dominant interaction for the set of tested genes appears to be synergism. We argue that gene expression patterns can be used to understand and predict the type of interaction expected when organisms are exposed simultaneously to natural and anthropogenic stressors.

  16. Biotic interactions modify multiple-stressor effects on juvenile brown trout in an experimental stream food web.

    Science.gov (United States)

    Bruder, Andreas; Salis, Romana K; Jones, Peter E; Matthaei, Christoph D

    2017-09-01

    Agricultural land use results in multiple stressors affecting stream ecosystems. Flow reduction due to water abstraction, elevated levels of nutrients and chemical contaminants are common agricultural stressors worldwide. Concurrently, stream ecosystems are also increasingly affected by climate change. Interactions among multiple co-occurring stressors result in biological responses that cannot be predicted from single-stressor effects (i.e. synergisms and antagonisms). At the ecosystem level, multiple-stressor effects can be further modified by biotic interactions (e.g. trophic interactions). We conducted a field experiment using 128 flow-through stream mesocosms to examine the individual and combined effects of water abstraction, nutrient enrichment and elevated levels of the nitrification inhibitor dicyandiamide (DCD) on survival, condition and gut content of juvenile brown trout and on benthic abundance of their invertebrate prey. Flow velocity reduction decreased fish survival (-12% compared to controls) and condition (-8% compared to initial condition), whereas effects of nutrient and DCD additions and interactions among these stressors were not significant. Negative effects of flow velocity reduction on fish survival and condition were consistent with effects on fish gut content (-25% compared to controls) and abundance of dominant invertebrate prey (-30% compared to controls), suggesting a negative metabolic balance driving fish mortality and condition decline, which was confirmed by structural equation modelling. Fish mortality under reduced flow velocity increased as maximal daily water temperatures approached the upper limit of their tolerance range, reflecting synergistic interactions between these stressors. Our study highlights the importance of indirect stressor effects such as those transferred through trophic interactions, which need to be considered when assessing and managing fish populations and stream food webs in multiple-stressor situations

  17. Interpersonal stressors and negative affect in individuals with borderline personality disorder and community adults in daily life: A replication and extension.

    Science.gov (United States)

    Hepp, Johanna; Lane, Sean P; Wycoff, Andrea M; Carpenter, Ryan W; Trull, Timothy J

    2018-02-01

    Affective instability and interpersonal stress are key features of borderline personality disorder (BPD). They were shown to covary in the daily lives of patients in a recent ambulatory assessment study (Hepp et al., 2017) that observed comparatively larger positive associations between interpersonal stressors and negative affect in individuals with BPD than those with depressive disorders. The present study sought to replicate these findings, collecting data on hostility, sadness, fear, and rejection or disagreement events from 56 BPD and 60 community control participants for 21 days, 6 times a day. Using identical statistical procedures, the positive associations between momentary rejection/disagreement and hostility, sadness, and fear were replicated. Again replicating the original study, the rejection-hostility, rejection-sadness, and disagreement-hostility associations were significantly stronger in the BPD group. Time-lagged analyses extended the original study, revealing that rejection was associated with subsequent hostility and sadness more strongly in the BPD group, as was disagreement with subsequent hostility and fear. Though small, we argue that the observed group differences reflect meaningful pervasive responses in a daily life context. Future research should consider these when implementing affect regulation strategies that are applicable in interpersonal contexts for all individuals, but particularly those with BPD. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  18. Aluminium Toxicity to Plants as Influenced by the Properties of the Root Growth Environment Affected by Other Co-Stressors: A Review.

    Science.gov (United States)

    Siecińska, Joanna; Nosalewicz, Artur

    Aluminium toxicity to crops depends on the acidity of the soil and specific plant resistance. However, it is also strongly affected by other environmental factors that have to be considered to properly evaluate the resultant effects on plants. Observed weather perturbations and predicted climate changes will increase the probability of co-occurrence of aluminium toxicity and other abiotic stresses.In this review the mechanisms of plant-aluminium interactions are shown to be influenced by soil mineral nutrients, heavy metals, organic matter, oxidative stress and drought. Described effects of aluminium toxicity include: root growth inhibition, reduction in the uptake of mineral nutrients resulting from the inhibition of transport processes through ion channels; epigenetic changes to DNA resulting in gene silencing. Complex processes occurring in the rhizosphere are highlighted, including the role of soil organic matter and aluminium detoxification by mucilage.There is a considerable research gap in the understanding of root growth in the soil environment in the presence of toxic aluminium concentrations as affected by interactions with abiotic stressors. This knowledge is important for the selection of feasible methods aimed at the reduction of negative consequences of crop production in acidic soils affected by adverse growth environment.

  19. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  20. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-03-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  1. Large herbivores affect forest ecosystem functions by altering the structure of dung beetle communities

    Science.gov (United States)

    Iida, Taichi; Soga, Masashi; Koike, Shinsuke

    2018-04-01

    Dramatic increases in populations of large mammalian herbivores have become a major ecological issue, particularly in the northern hemisphere, due to their substantial impacts on both animal and plant communities through processes such as grazing, browsing, and trampling. However, little is known about the consequences of these population explosions on ecosystem functions. Here, we experimentally investigated how the population density of sika deer (Cervus nippon) in temperate deciduous forest areas in Japan affected the decomposition of mammal dung by dung beetles, which is a key process in forest ecosystems. We measured a range of environmental variables (e.g., vegetation cover, soil hardness) and the dung decomposition rate, measured as the amount of deer dung decomposed during one week, and sampled dung beetles at 16 study sites with three different deer densities (high/intermediate/low). We then used structural equation modeling to investigate the relationships between deer density, environmental variables, the biomass of dung beetles (classified into small or large species), and the dung decomposition rate. We found that the biomass of small species increased with increasing deer density, whereas that of large species was not related to deer density. Furthermore, the dung decomposition rate was positively related to the biomass of small species but unrelated to that of large species. Overall, our results showed that an increase in deer density affects the decomposition rate of mammal dung by changing the structure of dung beetle communities (i.e., increasing the number of small dung beetles). Such an understanding of how increases in large herbivore populations affect ecosystem functions is important for accurately evaluating the ecological consequences of their overabundance and ultimately managing their populations appropriately.

  2. Analysis of chemical factors affecting marine ecosystem around nuclear power plant

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Choi, Yoon Dong; Chun, Ki Jeong; Kim, Jin Kyu; Jung, Kyeong Chai; Lee, Yeong Keun; Park, Hyo Kook

    1994-06-01

    The ecological data of the coastal area of Youngkwang nuclear power plant from 1987 to 1993 were comprehensively analyzed, and various physical and chemical properties of sea water and sediments were measured. Major factors affecting phytoplankton standing crops were suspended substances, nitrate, and silicate. The contents of iron, chromium, copper, and sulfur in sediments sampled from the discharge channel were slightly higher than those in the other areas. In order to qantify the chemical impacts on marine ecosystem, it is desirable that a systematic survey be made through the whole year cycle to assure the consistency and confidence of the related data. (Author)

  3. Coastal forests and groundwater: Using case studies to understand the effects of drivers and stressors for resource management

    Science.gov (United States)

    Timothy Callahan; Devendra Amatya; Peter Stone

    2017-01-01

    Forests are receiving more attention for the ecosystem goods and services they provide and the potential change agents that may affect forest health and productivity. Highlighting case examples from coastal forests in South Carolina, USA, we describe groundwater processes with respect to stressors and potential responses of a wetland-rich forested landscape,...

  4. Climate change and wildfire effects in aridland riparian ecosystems: An examination of current and future conditions

    Science.gov (United States)

    D. Max Smith; Deborah M. Finch

    2017-01-01

    Aridland riparian ecosystems are limited, the climate is changing, and further hydrological change is likely in the American Southwest. To protect riparian ecosystems and organisms, we need to understand how they are affected by disturbance processes and stressors such as fire, drought, and non-native plant invasions. Riparian vegetation is critically important as...

  5. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, Ulf

    1997-02-01

    The stratospheric ozone depletion and the concomitant increase in ultraviolet-B (UV-B, 280-320 nm) radiation is of global concern due to the effects of UV-B on living organisms. To investigate the effects of increased levels of UV-B, a field irradiation system was established at a subarctic dwarf shrub heath in Northern Sweden (68 deg N). An ozone depletion of 15% under clear sky conditions was simulated over a naturally growing ecosystem. The response of both individual components and processes was studied to reveal changes in ecosystem structure and function. Species with different life strategies (evergreen or deciduous) responded differently both in magnitude and direction. The evergreen species were more responsive to UV-B regarding shoot growth, which could be due to cumulative effects in long-lived tissues, since the retardation in relative growth increased over time of exposure. Leaves of evergreen species became thicker under enhanced UV-B, while leaves of deciduous species became thinner. Decomposition studies (laboratory and in situ) showed that indirect effects of UV-B, due to changes in leaf tissue chemistry affected microbial activity and slowed down the decomposition rate. More directly, UV-B decreased the abundance of some fungal species and hence the composition of species. However, no altered decomposition rate was found when decomposition progressed under high UV-B even if the microorganisms were fewer. This could be due to the increased direct photo degradation of litter that compensates for lower microbial activity. The decomposition rate is therefore strongly dependent on the interception of UV-B at the litter layer. This research has shown that ecosystem components and processes are affected in a number of ways and that there are indications of changes in species composition in a long-term perspective due to differences in responsiveness between the different species. 128 refs, 7 figs

  6. Rising tides, cumulative impacts and cascading changes to estuarine ecosystem functions.

    Science.gov (United States)

    O'Meara, Theresa A; Hillman, Jenny R; Thrush, Simon F

    2017-08-31

    In coastal ecosystems, climate change affects multiple environmental factors, yet most predictive models are based on simple cause-and-effect relationships. Multiple stressor scenarios are difficult to predict because they can create a ripple effect through networked ecosystem functions. Estuarine ecosystem function relies on an interconnected network of physical and biological processes. Estuarine habitats play critical roles in service provision and represent global hotspots for organic matter processing, nutrient cycling and primary production. Within these systems, we predicted functional changes in the impacts of land-based stressors, mediated by changing light climate and sediment permeability. Our in-situ field experiment manipulated sea level, nutrient supply, and mud content. We used these stressors to determine how interacting environmental stressors influence ecosystem function and compared results with data collected along elevation gradients to substitute space for time. We show non-linear, multi-stressor effects deconstruct networks governing ecosystem function. Sea level rise altered nutrient processing and impacted broader estuarine services ameliorating nutrient and sediment pollution. Our experiment demonstrates how the relationships between nutrient processing and biological/physical controls degrade with environmental stress. Our results emphasise the importance of moving beyond simple physically-forced relationships to assess consequences of climate change in the context of ecosystem interactions and multiple stressors.

  7. Interactive effects of three pervasive marine stressors in a post-disturbance coral reef

    Science.gov (United States)

    Gil, Michael A.; Goldenberg, Silvan U.; Ly Thai Bach, Anne; Mills, Suzanne C.; Claudet, Joachim

    2016-12-01

    Ecosystems are commonly affected by natural, episodic disturbances that can abruptly and drastically alter communities. Although it has been shown that resilient ecosystems can eventually recover to pre-disturbed states, the extent to which communities in early stages of recovery could be affected by multiple anthropogenic stressors is poorly understood. Pervasive and rising anthropogenic stressors in coastal marine systems that could interactively affect the recovery of these systems following natural disturbances include high sedimentation, nutrient enrichment, and overfishing. Using a 6-month field experiment, we examined the effects of all combinations of these three stressors on key functional groups in the benthic community growing on simulated, post-disturbance reef patches within a system recovering from large-scale natural disturbances (corallivorous seastar outbreak and cyclone). Our study revealed that sedimentation, nutrient enrichment, and overfishing (simulated using exclusion cages) interactively affected coral survival and algal growth, with taxon-specific effects at multiple scales. First, our treatments affected corals and algae differently, with sedimentation being more detrimental to macroalgal growth but less detrimental to coral ( Porites rus) survival in caged plots, driving significant interactions between sedimentation and caging for both taxa. We also observed distinct responses between coral species and between algal functional groups, with the most extensive responses from algal turf biomass, for which sedimentation suppressed the synergistic (positive) combined effect of nutrient enrichment and caging. Our findings suggest that different combinations of ubiquitous anthropogenic stressors, related to either sea- or land-based activities, interactively influence community recovery from disturbance and may alter species compositions in the resulting community. Our findings further suggest that anthropogenic stressors could promote further

  8. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the Sindh's coastal area

    International Nuclear Information System (INIS)

    Naqvi, S.R.; Inam, Z.

    2005-01-01

    Mangroves the ecological treasure of Sindh, are facing a steady decline due to in active Government policies and lack of interest of local people. Mangroves provide important breeding Zone of to the marine biodiversity because of the reduction of silt flows, the area of active growth of delta, has been reduced from an original estimate of 2600 sq km to about 260 sq km. Similarly, the area of Mangroves from 345,000 hectares, the area is now only 205000 hectares. Pakistani Mangroves rank 6th among the mangroves spread in 92 countries. Mangroves forests act as inter face b/w land and sea. It provides nutrients to marine fisheries and is vital healthy Ecosystem. During past 50 years, nearly 100,000 hectares have been destroyed. The destruction is quite high from 1975 to 1992. It is due to water shortage in the river Indus. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the coastal area. Thus to find root causes of degradation and its effects this study was made. (author)

  9. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

  10. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    Science.gov (United States)

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  11. Enchytraeids as indicator organisms for chemical stress in terrestrial ecosystems

    NARCIS (Netherlands)

    Didden, W.; Römbke, J.

    2001-01-01

    This review article surveys the available data on enchytraeid sensitivity toward chemical stress, and the effects of chemical stress on enchytraeid communities in terrestrial ecosystems. The factors affecting bioavailability of stressors to enchytraeids and the nature of direct and indirect effects

  12. How does whole ecosystem warming of a peatland affect methane production and consumption?

    Science.gov (United States)

    Hopple, A.; Brunik, K.; Keller, J.; Pfeifer-Meister, L.; Woerndle, G.; Zalman, C.; Hanson, P.; Bridgham, S. D.

    2017-12-01

    Peatlands are among Earth's most important terrestrial ecosystems due to their massive soil carbon (C) stores and significant release of methane (CH4) into the atmosphere. Methane has a sustained-flux global warming potential 45-times greater than carbon dioxide (CO2), and the accuracy of Earth system model projections relies on our mechanistic understanding of peatland CH4 cycling in the context of environmental change. The objective of this study was to determine, under in situ conditions, how heating of the peat profile affects ecosystem-level anaerobic C cycling. We assessed the response of CO2 and CH4 production, as well as the anaerobic oxidation of CH4 (AOM), in a boreal peatland following 13 months of deep peat heating (DPH) and 16 months of subsequent whole-ecosystem warming (surface and deep heating; WEW) as part of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in northern Minnesota, USA. The study uses a regression-based experimental design including 5 temperature treatments that warmed the entire 2 m peat profile from 0 to +9 °C above ambient temperature. Soil cores were collected at multiple depths (25-200 cm) from each experimental chamber at the SPRUCE site and anaerobically incubated at in situ temperatures for 1-2 weeks. Methane and CO2 production in surface peat were positively correlated with elevated temperature, but no consistent temperature response was found at depth (75-200 cm) following DPH. However, during WEW, we observed significant increases in both surface and deep peat methanogenesis with increasing temperature. Surface peat had greater CH4 production rates than deeper peat, implying that the increased CH4 emissions observed in the field were largely driven by surface peat warming. The CO2:CH4 ratio was inversely correlated with temperature across all depths following 16 months of WEW, indicating that the entire peat profile is becoming more methanogenic with warming. We also observed AOM throughout

  13. Does stress affect the joints? Daily stressors, stress vulnerability, immune and HPA axis activity, and short-term disease and symptom fluctuations in rheumatoid arthritis

    NARCIS (Netherlands)

    Evers, A.W.M.; Verhoeven, E.W.M.; Middendorp, H. van; Sweep, F.C.; Kraaimaat, F.W.; Donders, A.R.T.; Eijsbouts, A.E.; Laarhoven, A.I.M. van; Brouwer, S.J.M. de; Wirken, L.; Radstake, T.R.D.J.; Riel, P.L.C.M. van

    2014-01-01

    OBJECTIVES: Both stressors and stress vulnerability factors together with immune and hypothalamus-pituitary-adrenal (HPA) axis activity components have been considered to contribute to disease fluctuations of chronic inflammatory diseases, such as rheumatoid arthritis (RA). The aim of the present

  14. Species of conservation concern and environmental stressors: local regional and global effects: Chapter 6 in The Southern Nevada Agency Partnership science and research synthesis: science to support land management in southern Nevada

    Science.gov (United States)

    Ostoja, Steven M.; Brooks, Matthew L.; Chambers, Jeanne C.; Pendleton, Burton

    2013-01-01

    Species conservation has traditionally been based on individual species within the context of their requisite habitat, which is generally defined as the communities and ecosystems deemed necessary for their presence. Conservation decisions are hampered by the fact that environmental stressors that poetically threaten the persistence of species can operate at organizational levels larger than the habitat or home range of a focal species. Resource managers must therefore simultaneously consider local, regional, and/or global scale stressors for effective conservation and management of species of concern. The wide ranging effects associated with global stressors such as climate change may exceed or exacerbate the effects of local or regional stressors, they still need to understand the direct and interactive effects of global stressors and ultimately how they affect the lands they manage. Conservation of species in southern Nevada is further complication by the fact that the region includes one of the largest and fastest growing urban centers in North America. To accomplish the goal of species conservation, resource managers must identify actionable management options that mitigate the effects of local and regional stressor in the context of the effects of global stressors that are beyond their control. Species conservation is typically focused on a subset often referred to as species of conservation concern that have either demonstrated considerable decline or are naturally rare or have limited distributions. Stressors can directly and indirectly impact species in a variety of ways and through a diversity of mechanisms. Some stressors have been more intense in the past (e.g., livestock grazing) whereas other are now only emerging as new stressors (e.g., solar energy development, climate change). The primary stressors affecting southern Nevada ecosystems are listed in table 2.1 and reviewed in detail in Chapter 2. This chapter addresses Dub-goal 1.4 in the SNAP

  15. How will ocean acidification affect Baltic sea ecosystems? an assessment of plausible impacts on key functional groups.

    Science.gov (United States)

    Havenhand, Jonathan N

    2012-09-01

    Increasing partial pressure of atmospheric CO₂ is causing ocean pH to fall-a process known as 'ocean acidification'. Scenario modeling suggests that ocean acidification in the Baltic Sea may cause a ≤ 3 times increase in acidity (reduction of 0.2-0.4 pH units) by the year 2100. The responses of most Baltic Sea organisms to ocean acidification are poorly understood. Available data suggest that most species and ecologically important groups in the Baltic Sea food web (phytoplankton, zooplankton, macrozoobenthos, cod and sprat) will be robust to the expected changes in pH. These conclusions come from (mostly) single-species and single-factor studies. Determining the emergent effects of ocean acidification on the ecosystem from such studies is problematic, yet very few studies have used multiple stressors and/or multiple trophic levels. There is an urgent need for more data from Baltic Sea populations, particularly from environmentally diverse regions and from controlled mesocosm experiments. In the absence of such information it is difficult to envision the likely effects of future ocean acidification on Baltic Sea species and ecosystems.

  16. Gender differences in stressors and reactions to stressors among Jordanian university students.

    Science.gov (United States)

    Hamaideh, Shaher H

    2012-01-01

    Stress among university students has been a topic of interest for researchers and teachers for many years because it affects not only their academic performance but also their physiological and psychological health. Male and female students perceive and react to stressors differently due to their differences in appraising stressful situations. The aims of this study were to examine differences in the perception of stressors and reactions to stressors between male and female Jordanian university students, and to identify the best predictors of stressors among them. Descriptive cross-sectional design was employed. The Student-Life Stress Inventory was used to measure stressors and reactions to stressors of 465 male and 485 female Jordanian university students recruited through stratified random sampling. There were statistical differences between male and female students regarding their perception and reactions to stressors. Female students reported a higher perception of stressors in frustrations, conflict, pressures and changes, as well as emotional reactions to stressors. Male students reported higher behavioural and cognitive reactions to stressors than female students. Participation in stress workshops, perception of general health, and perception of stress level in general were found to predict stressors among male students, while mother's educational level, perception of general health, and perception of stress level in general were found to predict stressors among female students. This study showed that gender differences in perception of stressors and reactions to stressors are similar to previous studies conducted all over the world. Interventions can be developed to help students better cope with stress. Conducting specific stress-training programmes for male and female students will help in reducing stress levels.

  17. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure

    Science.gov (United States)

    Ferraro, Paul J.; Hanauer, Merlin M.

    2014-01-01

    To develop effective environmental policies, we must understand the mechanisms through which the policies affect social and environmental outcomes. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. We develop an approach to quantifying the mechanisms through which protected areas affect poverty. We focus on three mechanisms: changes in tourism and recreational services; changes in infrastructure in the form of road networks, health clinics, and schools; and changes in regulating and provisioning ecosystem services and foregone production activities that arise from land-use restrictions. The contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program have not yet been empirically estimated. Nearly two-thirds of the poverty reduction associated with the establishment of Costa Rican protected areas is causally attributable to opportunities afforded by tourism. Although protected areas reduced deforestation and increased regrowth, these land cover changes neither reduced nor exacerbated poverty, on average. Protected areas did not, on average, affect our measures of infrastructure and thus did not contribute to poverty reduction through this mechanism. We attribute the remaining poverty reduction to unobserved dimensions of our mechanisms or to other mechanisms. Our study empirically estimates previously unidentified contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program. We demonstrate that, with existing data and appropriate empirical methods, conservation scientists and policymakers can begin to elucidate the mechanisms through which ecosystem conservation programs affect human welfare. PMID:24567397

  18. Benthic macroinvertebrates and multiple stressors : quantification of the effects of multiple stressors in field, laboratory and model settings

    NARCIS (Netherlands)

    Peeters, E.T.H.M.

    2001-01-01

    Organisms are always exposed to several simultaneously operating stressors in nature. It appears that the combined effects of multiple stressors cannot be understood as a simple product of their individual effects. To understand how multiple stressors affect the composition and functioning

  19. Plant species and functional group combinations affect green roof ecosystem functions.

    Science.gov (United States)

    Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa

    2010-03-12

    Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green

  20. How clear-cutting affects fire severity and soil properties in a Mediterranean ecosystem.

    Science.gov (United States)

    Francos, Marcos; Pereira, Paulo; Mataix-Solera, Jorge; Arcenegui, Victoria; Alcañiz, Meritxell; Úbeda, Xavier

    2018-01-15

    Forest management practices in Mediterranean ecosystems are frequently employed to reduce both the risk and severity of wildfires. However, these pre-fire treatments may influence the effects of wildfire events on soil properties. The aim of this study is to examine the short-term effects of a wildfire that broke out in 2015 on the soil properties of three sites: two exposed to management practices in different years - 2005 (site M05B) and 2015 (site M15B) - and one that did not undergo any management (NMB) and to compare their properties with those recorded in a plot (Control) unaffected by the 2015 wildfire. We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (C mic ) and basal soil respiration (BSR). In the managed plots, a clear-cutting operation was conducted, whereby part of the vegetation was cut and left covering the soil surface. The AS values recorded at the Control site were significantly higher than those recorded at M05B, whereas the TN and SOM values at NMB were significantly higher than those recorded at M05B. IC was significantly higher at M05B than at the other plots. There were no significant differences in C/N ratio between the analyzed sites. Soil pH at M05B was significantly higher than the value recorded at the Control plot. Extractable Ca was significantly higher at NMB than at both M05B and the Control, while extractable Mg was significantly lower at M05B than at NMB. Extractable K was significantly lower at the Control than at the three fire-affected plots. C mic was significantly higher at NMB than at the Control. BSR, BSR/C and BSR/C mic values at the fire-affected sites were significantly lower than those recorded at the Control. No significant differences were identified in C mic /C. Overall, a comparison of the

  1. How disturbances and management practices affect bird communities in a Carpathian river ecosystem?

    Science.gov (United States)

    Lacko, Jozef; Topercer, Ján; Súľovský, Marek

    2018-04-01

    We studied how interactions between disturbances, succession, human alterations and other habitat and landscape attributes affect bird community patterns in a lower reach of a large West Carpathian river Váh with complex disturbance and alteration histories. Breeding-bird communities, their habitats (54 variables) and surrounding landscapes (11 metrics) were sampled using standardized point counts with limited distances at 40 riparian sites divided among two transects along a 12.9 km river stretch. The most frequent and abundant birds were generalists typically associated with forest edge habitats, such as Parus major, Sylvia atricapilla, Fringilla coelebs, Oriolus oriolus, Phylloscopus collybita, Sturnus vulgaris, Turdus merula and Luscinia megarhynchos. Abundances show significant increase at the lower transect responding apparently to greater size and heterogeneity of riparian habitats and more abundant food supply linked to more diverse and intense human influences in a suburban zone. Both indirect (NMDS) and direct ordination (CCA) revealed remarkably large number of evenly important factors underlying riparian bird-habitat interactions. It suggests considerable environmental heterogeneity and complexity of these interactions as a likely outcome of long and complex disturbance and alteration histories of the area. Yet structure and relative importance of first two gradients (longitudinal and lateral linkages) remains simple and stable, complying well with predictions of river continuum concept and stream ecosystem theory. Of the nine statistically significant variables most strongly correlated with first two CCA axes, percentages of Helianthus tuberosus, footpaths, fields, Calystegia sepium and steep banks uphold our hypotheses predicting significant effects of invasive species, visitor disturbances, agricultural land use and unaltered river banks/bed on bird community composition and structure. A small but significant contribution of patch size standard

  2. Solidago canadensis invasion affects soil N-fixing bacterial communities in heterogeneous landscapes in urban ecosystems in East China.

    Science.gov (United States)

    Wang, Congyan; Jiang, Kun; Zhou, Jiawei; Wu, Bingde

    2018-03-12

    Soil nitrogen-fixing bacterial communities (SNB) can increase the level of available soil N via biological N-fixation to facilitate successful invasion of several invasive plant species (IPS). Meanwhile, landscape heterogeneity can greatly enhance regional invasibility and increase the chances of successful invasion of IPS. Thus, it is important to understand the soil micro-ecological mechanisms driving the successful invasion of IPS in heterogeneous landscapes. This study performed cross-site comparisons, via metagenomics, to comprehensively analyze the effects of Solidago canadensis invasion on SNB in heterogeneous landscapes in urban ecosystems. Rhizospheric soil samples of S. canadensis were obtained from nine urban ecosystems [Three replicate quadrats (including uninvaded sites and invaded sites) for each type of urban ecosystem]. S. canadensis invasion did not significantly affect soil physicochemical properties, the taxonomic diversity of plant communities, or the diversity and richness of SNB. However, some SNB taxa (i.e., f_Micromonosporaceae, f_Oscillatoriaceae, and f_Bacillaceae) changed significantly with S. canadensis invasion. Thus, S. canadensis invasion may alter the community structure, rather than the diversity and richness of SNB, to facilitate its invasion process. Of the nine urban ecosystems, the diversity and richness of SNB was highest in farmland wasteland. Accordingly, the community invasibility of farmland wasteland may be higher than that of the other types of urban ecosystem. In brief, landscape heterogeneity, rather than S. canadensis invasion, was the strongest controlling factor for the diversity and richness of SNB. One possible reason may be the differences in soil electrical conductivity and the taxonomic diversity of plant communities in the nine urban ecosystems, which can cause notable shifts in the diversity and richness of SNB. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Identification and ranking of environmental threats with ecosystem vulnerability distributions.

    NARCIS (Netherlands)

    Zijp, Michiel C; Huijbregts, Mark A J; Schipper, Aafke M; Mulder, Christian; Posthuma, Leo

    2017-01-01

    Responses of ecosystems to human-induced stress vary in space and time, because both stressors and ecosystem vulnerabilities vary in space and time. Presently, ecosystem impact assessments mainly take into account variation in stressors, without considering variation in ecosystem vulnerability. We

  4. Assessing how green space types affect ecosystem services delivery in Porto, Portugal

    Science.gov (United States)

    Marisa Graça; Paulo Alves; João Gonçalves; David J. Nowak; Robert Hoehn; Paulo Farinha-Marques; Mario Cunha

    2018-01-01

    Significant advances have been made in identifying, quantifying and valuing multiple urban ecosystem services (UES), yet this knowledge remains poorly implemented in urban planning and management. One of the reasons for this low implementation is the insufficient thematic and spatial detail in UES research to provide guidance for urban planners and managers....

  5. Climate Change and Interacting Stressors: Implications for ...

    Science.gov (United States)

    EPA announced the release of the final document, Climate Change and Interacting Stressors: Implications for Coral Reef Management in American Samoa. This report provides a synthesis of information on the interactive effects of climate change and other stressors on the reefs of American Samoa as well as an assessment of potential management responses. This report provides the coral reef managers of American Samoa, as well as other coral reef managers in the Pacific region, with some management options to help enhance the capacity of local coral reefs to resist the negative effects of climate change. This report was designed to take advantage of diverse research and monitoring efforts that are ongoing in American Samoa to: analyze and compile the results of multiple research projects that focus on understanding climate-related stressors and their effects on coral reef ecosystem degradation and recovery; and assess implications for coral reef managment of the combined information, including possible response options.

  6. How forest management affects ecosystem services, including timber production and economic return

    DEFF Research Database (Denmark)

    Duncker, Philipp S.; Raulund-Rasmussen, Karsten; Gundersen, Per

    2012-01-01

    and services. By use of virtual but realistic datasets, we quantified, for multiple services, the effects of five forest management alternatives that form an intensity gradient. Our virtual forest management units represented Central European forest ecosystems in the submontane vegetation zone under a humid......–temperate climate with acidic soils. In this zone the European beech (Fagus sylvatica L.) is the dominant tree species. In order to assess the effects on ecosystem services, the untouched natural forest reserve served as a reference. Wherever possible, response functions were deduced to couple the various services...... via stand-level data to demonstrate trade-offs between the services. Management units comprised all development phases in the sense of a "normal forest". It was clearly illustrated that maximizing the rates of biomass production and carbon sequestration may conflict with protection of authentic...

  7. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    Czech Academy of Sciences Publication Activity Database

    Marek, Michal V.; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, I.

    2011-01-01

    Roč. 159, č. 5 (2011), s. 1035-1039 ISSN 0269-7491 R&D Projects: GA MŽP(CZ) SP/1A6/108/07; GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : carbon fluxes * net ecosystem exchange * spruce forest * beech forest * Grassland * agroecosystem * wetland * climate factors Subject RIV: EH - Ecology, Behaviour Impact factor: 3.746, year: 2011

  8. How climate affects ecosystems: A Canadian perspective on what we know

    International Nuclear Information System (INIS)

    Rowe, S.; Rizzo, B.

    1990-01-01

    The effects of climate change on ecosystems is discussed from the Canadian perspective. After a brief definition of terms, the implications of ecosystem theory are elaborated on. Impact models generated from altered climatic regimes can be categorized into two methodological streams: correlation modelling and dynamic modelling. Correlation modelling characterizes change on the basis of transfer functions linking climatic parameters and indices to specific ecological units. Correlation models can be applied at the species level or at the broader ecosystem level. Dynamic models are based on life history characteristics from birth to death, tracking such details as plant abundance, height and leaf area. Such models are most useful at the local rather than global scale. In Canada a number of broad scale correlation models have been attempted. These include the potential impacts of climatic change in the Praire provinces and Northwest Territories, a study relating the growing degree day isolines to ecological boundaries established in the ecoclimatic regions of Canada map, and the incorporation of nine climatic parameters in a correlation exercise, again using the ecoclimatic regions map. 14 refs

  9. Nitrogen and Carbon Cycling in a Grassland Community Ecosystem as Affected by Elevated Atmospheric CO2

    Directory of Open Access Journals (Sweden)

    H. A. Torbert

    2012-01-01

    Full Text Available Increasing global atmospheric carbon dioxide (CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystems and the long-term storage of carbon (C and nitrogen (N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L. Willd (Huisache. Seedlings of Acacia along with grass species were grown for 13 months at CO2 concentrations of 385 (ambient, 690, and 980 μmol mol−1. Elevated CO2 increased both C and N inputs from plant growth which would result in higher soil C from litter fall, root turnover, and excretions. Results from the incubation indicated an initial (20 days decrease in N mineralization which resulted in no change in C mineralization. However, after 40 and 60 days, an increase in both C and N mineralization was observed. These increases would indicate that increases in soil C storage may not occur in grass ecosystems that are invaded with Acacia over the long term.

  10. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne; Clark, D.; Atalah, J.; Jiang, W.; Taiapa, C.; Patterson, M.; Sinner, J.; Hewitt, J.

    2017-01-01

    loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  11. Abiotic stressors and stress responses

    DEFF Research Database (Denmark)

    Sulmon, Cecile; Van Baaren, Joan; Cabello-Hurtado, Francisco

    2015-01-01

    Abstract Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we...... review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact...... life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental...

  12. Prioritizing ecological restoration among sites in multi-stressor landscapes.

    Science.gov (United States)

    Neeson, Thomas M; Smith, Sigrid D P; Allan, J David; McIntyre, Peter B

    2016-09-01

    Most ecosystems are impacted by multiple local and long-distance stressors, many of which interact in complex ways. We present a framework for prioritizing ecological restoration efforts among sites in multi-stressor landscapes. Using a simple model, we show that both the economic and sociopolitical costs of restoration will typically be lower at sites with a relatively small number of severe problems than at sites with numerous lesser problems. Based on these results, we propose using cumulative stress and evenness of stressor impact as complementary indices that together reflect key challenges of restoring a site to improved condition. To illustrate this approach, we analyze stressor evenness across the world's rivers and the Laurentian Great Lakes. This exploration reveals that evenness and cumulative stress are decoupled, enabling selection of sites where remediating a modest number of high-intensity stressors could substantially reduce cumulative stress. Just as species richness and species evenness are fundamental axes of biological diversity, we argue that cumulative stress and stressor evenness constitute fundamental axes for identifying restoration opportunities in multi-stressor landscapes. Our results highlight opportunities to boost restoration efficiency through strategic use of multi-stressor datasets to identify sites that maximize ecological response per stressor remediated. This prioritization framework can also be expanded to account for the feasibility of remediation and the expected societal benefits of restoration projects. © 2016 by the Ecological Society of America.

  13. Investigation of road salts and biotic stressors on freshwater wetland communities.

    Science.gov (United States)

    Jones, Devin K; Mattes, Brian M; Hintz, William D; Schuler, Matthew S; Stoler, Aaron B; Lind, Lovisa A; Cooper, Reilly O; Relyea, Rick A

    2017-02-01

    The application of road deicing salts has led to the salinization of freshwater ecosystems in northern regions worldwide. Increased chloride concentrations in lakes, streams, ponds, and wetlands may negatively affect freshwater biota, potentially threatening ecosystem services. In an effort to reduce the effects of road salt, operators have increased the use of salt alternatives, yet we lack an understanding of how these deicers affect aquatic communities. We examined the direct and indirect effects of the most commonly used road salt (NaCl) and a proprietary salt mixture (NaCl, KCl, MgCl 2 ), at three environmentally relevant concentrations (150, 470, and 780 mg Cl - /L) on freshwater wetland communities in combination with one of three biotic stressors (control, predator cues, and competitors). The communities contained periphyton, phytoplankton, zooplankton, and two tadpole species (American toads, Anaxyrus americanus; wood frogs, Lithobates sylvaticus). Overall, we found the two road salts did not interact with the natural stressors. Both salts decreased pH and reduced zooplankton abundance. The strong decrease in zooplankton abundance in the highest NaCl concentration caused a trophic cascade that resulted in increased phytoplankton abundance. The highest NaCl concentration also reduced toad activity. For the biotic stressors, predatory stress decreased whereas competitive stress increased the activity of both tadpole species. Wood frog survival, time to metamorphosis, and mass at metamorphosis all decreased under competitive stress whereas toad time to metamorphosis increased and mass at metamorphosis decreased. Road salts and biotic stressors can both affect freshwater communities, but their effects are not interactive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Anthropogenic pollutants affect ecosystem services of freshwater sediments. The need for a 'triad plus x' approach

    Energy Technology Data Exchange (ETDEWEB)

    Gerbersdorf, Sabine Ulrike; Wieprecht, Silke [Stuttgart Univ. (Germany). Dept. of Hydraulic Engineering and Water Resources Management; Hollert, Henner; Brinkmann, Markus [RWTH Aachen Univ. (Germany). Dept. of Ecosystem Analysis; Schuettrumpf, Holger [RWTH Aachen Univ. (Germany). Inst. of Hydraulic Engineering and Water Resources Management; Manz, Werner [Koblenz-Landau Univ., Koblenz (Germany). Inst. for Integrated Natural Sciences

    2011-09-15

    Purpose: Freshwater sediments and their attached microbial communities (biofilms) are essential features of rivers and lakes, providing valuable ecosystem services such as nutrient recycling or self-purification which extend beyond the aquatic environment. Anthropogenic pollutants, whether from the industrial era or as a result of our contemporary lifestyles, can negatively affect these functions with hitherto unknown consequences on ecology, the economy and human health. Thus far, the singular view of the involved disciplines such as ecotoxicology, environmental microbiology, hydrology and geomorphology has prevented a deeper understanding of this emerging issue. Main features: This paper discusses briefly the progressions and the state-of-the-art methods within the disciplines of concern related to contaminated sediments, ranging from ecotoxicological test systems, microbiological/molecular approaches to unravel changes of microbial ecosystems, up to the modelling of sediment transport and sorption/desorption of associated pollutants. The first bilateral research efforts on contaminated sediments include efforts to assess ecotoxicological sediment risk including sediment mobility (i.e. ecotoxicology and engineering), enhance bioremediation potential (i.e. microbiology and ecotoxicology) or to understand biostabilisation processes of sediments by microbial assemblages (i.e. microbiology and engineering). Conclusions and perspectives: In freshwater habitats, acute, chronic and mechanism-specific toxic effects on organisms, shifts in composition, structure and functionality of benthic microbial communities, as well as the obstruction of important ecosystem services by continuously discharged and long-deposited pollutants, should be related to the in situ sediment dynamics. To achieve an improved understanding of the ecology of freshwater sediments and the impairment of their important ecosystem functions by human-derived pollutants, we suggest a 'triad plus x

  15. Changes in canopy structure and ant assemblages affect soil ecosystem variables as a foundation species declines

    DEFF Research Database (Denmark)

    Kendrick, Joseph A.; Ribbons, Relena Rose; Classen, Aimee Taylor

    2015-01-01

    in ant species composition would interact to alter soil ecosystem variables. In the Harvard Forest Hemlock Removal Experiment (HF-HeRE), established in 2003, T. canadensis in large plots were killed in place or logged and removed to mimic adelgid infestation or salvage harvesting, respectively. In 2006...... (richness and abundance) of ants increases rapidly as T. canadensis is lost from the stands. Because ants live and forage at the litter-soil interface, we hypothesized that environmental changes caused by hemlock loss (e.g., increased light and warmth at the forest floor, increased soil pH) and shifts......, we built ant exclosure subplots within all of the canopy manipulation plots to examine direct and interactive effects of canopy change and ant assemblage composition on soil and litter variables. Throughout HF-HeRE, T. canadensis was colonized by the adelgid in 2009, and the infested trees are now...

  16. Stressor Diversity: Introduction and Empirical Integration into the Daily Stress Model

    Science.gov (United States)

    Koffer, Rachel E.; Ram, Nilam; Conroy, David E.; Pincus, Aaron L.; Almeida, David M.

    2016-01-01

    The present study examined if and how stressor diversity, the extent to which one’s stressor events are spread across multiple types of stressors, contributes to daily affective well-being through the adult life span. Stressor diversity was examined as a unique predictor of daily affect and as a moderator of stressor exposure and stressor reactivity effects. Analyses span two independent studies of daily stress: the National Study of Daily Experiences with N=2,022 adults, aged 33–85, assessed over T=8 days, and the Intraindividual Study of Affect, Health, and Interpersonal Behavior with N=150 adults, aged 18–89, assessed over T=63 days. Across both studies, older age was associated with less stressor diversity. Additionally, multivariate multilevel models indicated higher stressor diversity was linked with better affective well-being. Age, however, was not a consistent moderator of such associations. The combination of low stressor diversity and high stressor exposure is discussed as an operationalization of chronic stressors, and this combination was associated with particularly high negative affect and low positive affect. We believe further work will benefit from including both the frequency and diversity of stressor experiences in analyses in order to better characterize individuals’ stressor experiences. PMID:27294713

  17. Stressor diversity: Introduction and empirical integration into the daily stress model.

    Science.gov (United States)

    Koffer, Rachel E; Ram, Nilam; Conroy, David E; Pincus, Aaron L; Almeida, David M

    2016-06-01

    The present study examined whether and how stressor diversity, the extent to which stressor events are spread across multiple types of stressors, contributes to daily affective well-being through the adult life span. Stressor diversity was examined as a unique predictor of daily affect and as a moderator of stressor exposure and stressor reactivity effects. Analyses span 2 independent studies of daily stress: the National Study of Daily Experiences with N = 2,022 adults, aged 33 to 85 years, assessed over T = 8 days, and the Intraindividual Study of Affect, Health, and Interpersonal Behavior with N = 150 adults, aged 18 to 89 years, assessed over T = 63 days. Across both studies, older age was associated with less stressor diversity. Additionally, multivariate multilevel models indicated higher stressor diversity was linked with better affective well-being. Age, however, was not a consistent moderator of such associations. The combination of low stressor diversity and high stressor exposure is discussed as an operationalization of chronic stressors, and this combination was associated with particularly high negative affect and low positive affect. We believe further work will benefit from including both the frequency and diversity of stressor experiences in analyses in order to better characterize individuals' stressor experiences. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  18. Multi-scale trends analysis of landscape stressors in an urbanizing coastal watershed

    Science.gov (United States)

    Anthropogenic land based stressors within a watershed can deliver major impacts to downstream and adjacent coastal waterways affecting water quality and estuarine habitats. Our research focused on a subset of non-point sources of watershed stressors specifically, human population...

  19. Glomalin in a mediterranean ecosystem affected by mining activities and its contribution to heavy metals sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo, P.; Meier, F.; Borie, G.; Borie, F.

    2009-07-01

    Glomalin-related soil protein (GRSP), a glycoprotein produced by arbuscular mycorrhizal fungi (AMF) and usually presents in high amounts in soil, may stabilize heavy metals such as Cu an Zn in soils affected by mining activities, as large areas of central Chile. (Author)

  20. 5,7-DHT lesion of the dorsal raphe nuclei impairs object recognition but not affective behavior and corticosterone response to stressor in the rat.

    Science.gov (United States)

    Lieben, Cindy K J; Steinbusch, Harry W M; Blokland, Arjan

    2006-04-03

    Previous studies with acute tryptophan depletion, leading to transient central 5-HT reductions, showed no effects on affective behavior but impaired object memory. In the present study, the behavioral effects of a 5,7-dihydroxytryptamine (5,7-DHT) lesion in the dorsal raphe were evaluated in animal models of anxiety (open field test), depression (forced swimming test), behavioral inhibition (discrete fixed interval test) and cognition (object recognition task). The corticosterone response to a stress condition was examined at several intervals after 5,7-DHT treatment. The substantial reduction in neuronal 5-HT markers in the dorsal raphe did not affect anxiety-related, depressive-like or impulsive behavior. Compared to the SHAM group, the lesioned rats showed a lower response latency to obtain a reward, indicating a quick and accurate reaction to a stimulus. No differences were found in the progressive ratio test for food motivation. A marked impairment in object recognition was found. The 5,7-DHT treatment did not affect the corticosterone response to a stressful situation. Overall, these results corroborate studies with acute tryptophan depletion suggesting a role of 5-HT in object memory, but not affective behavior.

  1. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

    Science.gov (United States)

    Constable, Andrew J; Melbourne-Thomas, Jessica; Corney, Stuart P; Arrigo, Kevin R; Barbraud, Christophe; Barnes, David K A; Bindoff, Nathaniel L; Boyd, Philip W; Brandt, Angelika; Costa, Daniel P; Davidson, Andrew T; Ducklow, Hugh W; Emmerson, Louise; Fukuchi, Mitsuo; Gutt, Julian; Hindell, Mark A; Hofmann, Eileen E; Hosie, Graham W; Iida, Takahiro; Jacob, Sarah; Johnston, Nadine M; Kawaguchi, So; Kokubun, Nobuo; Koubbi, Philippe; Lea, Mary-Anne; Makhado, Azwianewi; Massom, Rob A; Meiners, Klaus; Meredith, Michael P; Murphy, Eugene J; Nicol, Stephen; Reid, Keith; Richerson, Kate; Riddle, Martin J; Rintoul, Stephen R; Smith, Walker O; Southwell, Colin; Stark, Jonathon S; Sumner, Michael; Swadling, Kerrie M; Takahashi, Kunio T; Trathan, Phil N; Welsford, Dirk C; Weimerskirch, Henri; Westwood, Karen J; Wienecke, Barbara C; Wolf-Gladrow, Dieter; Wright, Simon W; Xavier, Jose C; Ziegler, Philippe

    2014-10-01

    Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed. © 2014 John Wiley & Sons Ltd.

  2. Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem.

    Science.gov (United States)

    Hamilton, Jordan G; Farrell, Richard E; Chen, Ning; Feng, Renfei; Reid, Joel; Peak, Derek

    2016-03-01

    HudBay Minerals, Inc., has mined and/or processed Zn and Cu ore in Flin Flon, MB, Canada, since the 1930s. The boreal forest ecosystem and soil surrounding these facilities have been severely impacted by mixed metal contamination and HSO deposition. Zinc is one of the most prevalent smelter-derived contaminants and has been identified as a key factor that may be limiting revegetation. Metal toxicity is related to both total concentrations and speciation; therefore, X-ray absorption spectroscopy and X-ray fluorescence mapping were used to characterize Zn speciation in soils throughout the most heavily contaminated areas of the landscape. Zinc speciation was linked to two distinct soil types. Group I soils consist of exposed soils in weathered positions of bedrock outcrops with Zn present primarily as franklinite, a (ZnFeO) spinel mineral. Group II soils are stabilized by an invasive metal-tolerant grass species, with Zn found as a mixture of octahedral (Fe oxides) and tetrahedral Mn oxides) adsorption complexes with a franklinite component. Soil erosion influences Zn speciation through the redistribution of Zn and soil particulates from Group I landscape positions to Group II soils. Despite Group II soils having the highest concentrations of CaCl-extractable Zn, they support metal-tolerant plant growth. The metal-tolerant plants are probably preferentially colonizing these areas due to better soil and nutrient conditions as a result of soil deposition from upslope Group I areas. Zinc concentration and speciation appears to not influence the colonization by metal-tolerant grasses, but the overall soil properties and erosion effects prevent the revegetation by native boreal forest species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. Environmental and Microbial Features Affecting Denitrification and Anammox Hotspots in an Estuarine Ecosystem

    Science.gov (United States)

    Lisa, J.; Song, B.; Lefcheck, J. S.; Tobias, C. R.

    2016-02-01

    Biogeochemical hotspots are characterized as a few sites that exhibit extremely high reaction rates relative to surrounding area, and often account for a high percentage of the overall reaction rates in an ecosystem. Criteria for quantitatively identifying these sites have not been well established. Further, the underlying mechanisms of hotspots have been described in terms of environmental conditions, with little attention paid to the microbial community. The objectives of this study were to establish quantitative criteria to identify denitrification and anammox hotspots, and determine the underlying microbial and environmental factors responsible for elevated N2 production. We used 15N isotope pairing incubation experiments to measure denitrification and anammox rates in the New River Estuary, NC. Quantitative PCR assays of nitrous oxide reductase (nosZ Clades I and II) and hydrazine oxidoreductase (hzo) genes were conducted to estimate denitrifier and anammox abundance. Structural Equation Modeling (SEM) was used to elucidate complex causal relationships between environmental and biological variables. Denitrification hotspots, quantitatively defined as statistical outliers, accounted for 35.6% total denitrification while comprising only 7.3% of the sites. Anammox hotspots,10.6% of the sites, accounted for 60.9% of total anammox. SEM revealed increased sediment organics at lower salinities supported higher functional gene abundance, which in turn resulted in higher N2 production. Surprisingly, denitrification rates were significantly and positively correlated with nosZ Clade II gene abundance, after accounting for the non-significant contributions of the naturally more abundant nosZ Clade I, and other environmental covariates. This is the first time that a quantitative definition of biogeochemical hotspots was put forth and used to determine the importance of anammox and denitrification hotspots in estuarine nitrogen removal capacity. Despite the low area

  4. [Multi-scenario simulation and prediction of ecosystem services as affected by urban expansion: A case study in coastal area of Tianjin, North China].

    Science.gov (United States)

    Huang, Huan-Chun; Yun, Ying-Xia; Miao, Zhan-Tang; Hao, Cui; Li, Hong-yuan

    2013-03-01

    Based on the modified Logistic-CA model, and taking the coastal area of Tianjin as a case, this paper simulated the spatial evolution patterns of ecosystem services as affected by the urban expansion in 2011-2020 under the scenarios of historical extrapolation, endogenous development, and exogenous development. Overall, the total ecosystem services of the study area under the three scenarios were generally the same, and the functional region with the lowest level ecosystem services had the identical spatial pattern. However, the spatial evolution patterns of the ecosystem services of the study area under the three scenarios had a great difference. The functional regions with lower-level ecosystem services grew in a cross-shaped pattern, with the Tanggu downtown as a center, and finally formed a full connectivity area along the Haihe River and coastal zone.

  5. Analysing the impact of multiple stressors in aquatic biomonitoring data: A 'cookbook' with applications in R.

    Science.gov (United States)

    Feld, Christian K; Segurado, Pedro; Gutiérrez-Cánovas, Cayetano

    2016-12-15

    Multiple stressors threaten biodiversity and ecosystem integrity, imposing new challenges to ecosystem management and restoration. Ecosystem managers are required to address and mitigate the impact of multiple stressors, yet the knowledge required to disentangle multiple-stressor effects is still incomplete. Experimental studies have advanced the understanding of single and combined stressor effects, but there is a lack of a robust analytical framework, to address the impact of multiple stressors based on monitoring data. Since 2000, the monitoring of Europe's waters has resulted in a vast amount of biological and environmental (stressor) data of about 120,000 water bodies. For many reasons, this data is rarely exploited in the multiple-stressor context, probably because of its rather heterogeneous nature: stressors vary and are mixed with broad-scale proxies of environmental stress (e.g. land cover), missing values and zero-inflated data limit the application of statistical methods and biological indicators are often aggregated (e.g. taxon richness) and do not respond stressor-specific. Here, we present a 'cookbook' to analyse the biological response to multiple stressors using data from biomonitoring schemes. Our 'cookbook' includes guidance for the analytical process and the interpretation of results. The 'cookbook' is accompanied by scripts, which allow the user to run a stepwise analysis based on his/her own data in R, an open-source language and environment for statistical computing and graphics. Using simulated and real data, we show that the recommended procedure is capable of identifying stressor hierarchy (importance) and interaction in large datasets. We recommend a minimum number of 150 independent observations and a minimum stressor gradient length of 75% (of the most relevant stressor's gradient in nature), to be able to reliably rank the stressor's importance, detect relevant interactions and estimate their standardised effect size. We conclude with

  6. The false promises of coal exploitation: How mining affects herdsmen well-being in the grassland ecosystems of Inner Mongolia

    International Nuclear Information System (INIS)

    Dai, G.S.; Ulgiati, S.; Zhang, Y.S.; Yu, B.H.; Kang, M.Y.; Jin, Y.; Dong, X.B.; Zhang, X.S.

    2014-01-01

    The grasslands of Inner Mongolia are not only the source of the necessary resources for the survival and development of herdsmen, but also represent a significant green ecological barrier in North China. Coal-mining production is important in maintaining GDP growth in Inner Mongolia. However, over-exploitation has created serious problems, such as pollution of the environment and significant decreases in grassland ecosystem services, in addition to impacting the well-being of herdsmen and other humans. Based on questionnaires survey performed among 864 herdsmen addressing the relationship between coal exploitation in grasslands and human well-being in Xilinguole League in Inner Mongolia, we found that (1) coal resource exploitation in these grasslands does not benefit the herdsmen by increasing their income; (2) the rapid development of this resource has not obviously materially improved the life of the herdsmen; and (3) these activities have increased the risks that herdsman will have to endure in the future. Overall, coal resource exploitation in grasslands has more negative than positive effects on the well-being of herdsmen. We propose the conservation of coal resources and improvement of ecological compensation should be carried out without blindly pursuing economic growth, instead of focusing on economic development and structural adjustments. - Highlights: • Evaluation of the human well-being of the Xilinguole grassland, Inner Mongolia, China. • Impact of mining affects herdsmen well-being in grassland ecosystem. • Quantity of questionnaires survey. • Addressing the relationship between coal exploitation in grasslands and human well-being

  7. Reviewing ecosystems affected by the fallout from the Chernobyl reactor accident with respect to the resulting population exposure

    International Nuclear Information System (INIS)

    Fielitz, U.

    1999-01-01

    The research project is intended to yield information on the current radiological situation resulting from the Chernobyl fallout. Environmental materials of particular interest are game, mushrooms, berries, and forest stands in the most heavily affected forest ecosystem of the Bavarian forest area called Bayerischer Wald. This area has been intensively monitored in the period from 1988 until 1994, so that the development up to the current radiological situation can be analysed. Activities under the research project will encompass: Measurement of the radioactive contamination of specimens of the game population in the Bodenmais forest area of 7 500 hectares. Measurement of seasonal variations of the radiocesium activity in various indicator plants of the food chain of the game population. Soil sampling and radioactivity measurement at 2 cm depth intervals. The measuring work will be carried out in two areas which have been earmarked for monitoring over the last eight years (B1 and B2). The measured results will be compared with earlier data, and long-term space and time-dependent information on the transfer of radiocesium in the forest ecosystem under review will be derived. (orig./CB) [de

  8. Emotional versus cognitive rumination: are they differentially affecting long-term psychological health? The impact of stressors and personality in dental students.

    Science.gov (United States)

    Hamesch, Ulla; Cropley, Mark; Lang, Jessica

    2014-08-01

    In the process of recovery from work, rumination is considered as an important mediating variable in the relationship between work demands and psychological health outcomes. Past research differentiated affective rumination from problem-solving pondering. The aim of the present study was to test a moderated mediation model for these two distinct ruminative states and to show how personality (i.e. neuroticism and conscientiousness) can alter the mediating effect. The present study is based on 119 surveys from dental students with a time lag of 6 months. Participants filled out questionnaires assessing specific study-relevant performance demands, rumination and personality and a screening measure for psychological health status. Neuroticism was found to moderate the demand-affective rumination association, but conscientiousness did not moderate the demand-problem-solving pondering association. Moderated mediation analysis revealed that affective rumination mediates the impact of demands on psychological health only for individuals low in neuroticism. Findings are discussed regarding potential interventions for dental students to prevent negative psychological health outcomes due to increased work-related demands in the long term. Copyright © 2014 John Wiley & Sons, Ltd.

  9. Ecosystem screening approach for pathogen-associated microorganisms affecting host disease.

    Science.gov (United States)

    Galiana, Eric; Marais, Antoine; Mura, Catherine; Industri, Benoît; Arbiol, Gilles; Ponchet, Michel

    2011-09-01

    The microbial community in which a pathogen evolves is fundamental to disease outcome. Species interacting with a pathogen on the host surface shape the distribution, density, and genetic diversity of the inoculum, but the role of these species is rarely determined. The screening method developed here can be used to characterize pathogen-associated species affecting disease. This strategy involves three steps: (i) constitution of the microbial community, using the pathogen as a trap; (ii) community selection, using extracts from the pathogen as the sole nutrient source; and (iii) molecular identification and the screening of isolates focusing on their effects on the growth of the pathogen in vitro and host disease. This approach was applied to a soilborne plant pathogen, Phytophthora parasitica, structured in a biofilm, for screening the microbial community from the rhizosphere of Nicotiana tabacum (the host). Two of the characterized eukaryotes interfered with the oomycete cycle and may affect the host disease. A Vorticella species acted through a mutualistic interaction with P. parasitica, disseminating pathogenic material by leaving the biofilm. A Phoma species established an amensal interaction with P. parasitica, strongly suppressing disease by inhibiting P. parasitica germination. This screening method is appropriate for all nonobligate pathogens. It allows the definition of microbial species as promoters or suppressors of a disease for a given biotope. It should also help to identify important microbial relationships for ecology and evolution of pathogens.

  10. Response of seagrass indicators to shifts in environmental stressors: A global review and management synthesis

    KAUST Repository

    Roca, G.

    2016-01-01

    Although seagrass-based indicators are widely used to assess coastal ecosystem status, there is little universality in their application. Matching the plethora of available indicators to specific management objectives requires a detailed knowledge of their species-specific sensitivities and their response time to environmental stressors. We conducted an extensive survey of experimental studies to determine the sensitivity and response time of seagrass indicators to ecosystem degradation and recovery. We identified seagrass size and indicator type (i.e. level of biological organization of the measure) as the main factors affecting indicator sensitivity and response time to degradation and recovery. While structural and demographic parameters (e.g. shoot density, biomass) show a high and unspecific sensitivity, biochemical/physiological indicators present more stressor-specific responses and are the most sensitive detecting early phases of environmental improvement. Based on these results we present a simple decision tree to assist ecosystem managers to match adequate and reliable indicators to specific management goals. © 2015 Elsevier Ltd. All rights reserved.

  11. Entrepreneurial stressors as predictors of entrepreneurial burnout.

    Science.gov (United States)

    Wei, Xueyan; Cang, Shuangxin; Hisrich, Robert D

    2015-02-01

    Research on the effects of entrepreneurial stressors is limited, especially regarding its relation to the burnout that frequently occurs in the process of starting and growing a venture. The effect of the role of entrepreneurial stressors (workload, competitive comparison, demands-of-knowledge, managing responsibility, and resource requirements) on burnout (emotional exhaustion, depersonalization, and reduced personal accomplishment) was examined in a Chinese sample of entrepreneurs. Entrepreneurial stressors emerged as a significant predictor of burnout in the process of entrepreneurship in a sample of 289 entrepreneurs (63.8% men; M age = 26.2 yr.; 39.6% of their parents have been self-employed). The findings clarify the functional relationship between entrepreneurial stressors and burnout. Entrepreneurial stressors played multiple roles. Managing responsibility was an active contributor to the sense of achievement and to emotional exhaustion. Workload was an active contributor to emotional exhaustion. Demands-of-knowledge negatively affected three of the dimensions of burnout. Theoretical and practical implications for management of the effect of these relationships are discussed.

  12. Oxidative responsiveness to multiple stressors in the key Antarctic species, Adamussium colbecki: Interactions between temperature, acidification and cadmium exposure.

    Science.gov (United States)

    Benedetti, Maura; Lanzoni, Ilaria; Nardi, Alessandro; d'Errico, Giuseppe; Di Carlo, Marta; Fattorini, Daniele; Nigro, Marco; Regoli, Francesco

    2016-10-01

    High-latitude marine ecosystems are ranked to be among the most sensitive regions to climate change since highly stenothermal and specially adapted organisms might be seriously affected by global warming and ocean acidification. The present investigation was aimed to provide new insights on the sensitivity to such environmental stressors in the key Antarctic species, Adamussium colbecki, focussing also on their synergistic effects with cadmium exposure, naturally abundant in this area for upwelling phenomena. Scallops were exposed for 2 weeks to various combinations of Cd (0 and 40 μgL-1), pH (8.05 and 7.60) and temperature (-1 and +1 °C). Beside Cd bioaccumulation, a wide panel of early warning biomarkers were analysed in digestive glands and gills including levels of metallothioneins, individual antioxidants and total oxyradical scavenging capacity, onset of oxidative cell damage like lipid peroxidation, lysosomal stability, DNA integrity and peroxisomal proliferation. Results indicated reciprocal interactions between multiple stressors and their elaboration by a quantitative hazard model based on the relevance and magnitude of effects, highlighted a different sensitivity of analysed tissues. Due to cellular adaptations to high basal Cd content, digestive gland appeared more tolerant toward other prooxidant stressors, but sensitive to variations of the metal. On the other hand, gills were more affected by various combinations of stressors occurring at higher temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. African dust carries microbes across the ocean: are they affecting human and ecosystem health?

    Science.gov (United States)

    Kellogg, Christina A.; Griffin, Dale W.

    2003-01-01

    Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

  14. Organisational stressors, coping, and outcomes in competitive sport.

    Science.gov (United States)

    Arnold, Rachel; Fletcher, David; Daniels, Kevin

    2017-04-01

    Organisational stressors are associated with positive and negative outcomes in extant literature; however, little is known about which demands predict which outcomes. Extant theory and literature also suggests that coping style may influence an individual's resilience or vulnerability to stressors and, subsequently, their psychological responses and outcomes. The purpose of this study was, therefore, to examine the main effects of organisational stressors and coping styles on various outcomes (e.g., positive and negative affect, performance satisfaction). Sport performers (n = 414) completed measures of organisational stressors, coping styles, positive and negative affect, and performance satisfaction. Multiple regression analyses revealed positive relationships of both goals and development stressors (duration and intensity) and team and culture stressors (frequency and intensity) on negative affect. Furthermore, problem-focused coping was positively related to positive affect, and emotion-focused coping was positively related to negative affect. This study furthers theoretical knowledge regarding the associations that both organisational stressors (and their dimensions) and coping styles can have with various outcomes, and practical understanding regarding the optimal design of stress management interventions.

  15. Mapping the future: U.S. exposure to multiple landscape stressors

    Science.gov (United States)

    Marie Oliver; Becky Kerns; John Kim; Jeff. Kline

    2017-01-01

    Landscape exposure to multiple stressors can pose risks to human health, biodiversity, and ecosystem services. Attempts to study, control, or mitigate these stressors can strain public and private budgets. An interdisciplinary team of Pacific Northwest Research Station and Oregon State University scientists created maps of the conterminous United States that indicate...

  16. Toward a Better Understanding of the Effects of Hindrance and Challenge Stressors on Work Behavior

    Science.gov (United States)

    Webster, Jennica R.; Beehr, Terry A.; Christiansen, Neil D.

    2010-01-01

    This study investigated the processes whereby hindrance and challenge stressors may affect work behavior. Three mechanisms were examined to explain the differential effects these stressors have demonstrated: job satisfaction, strains, and work self-efficacy. A model is proposed in which both types of stressors will result in increases in strains,…

  17. The impact on environmental stressors on apiculture in Africa | Maus ...

    African Journals Online (AJOL)

    Honeybees are exposed to various environmental stressors that can significantly ... Many of the relevant species appear to have been introduced to Africa only ... individual factor adversely affecting bee health in Europe and North America, ...

  18. Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment.

    Directory of Open Access Journals (Sweden)

    Jeremy J Piggott

    Full Text Available Changes to land use affect streams through nutrient enrichment, increased inputs of sediment and, where riparian vegetation has been removed, raised water temperature. We manipulated all three stressors in experimental streamside channels for 30 days and determined the individual and pair-wise combined effects on benthic invertebrate and algal communities and on leaf decay, a measure of ecosystem functioning. We added nutrients (phosphorus+nitrogen; high, intermediate, natural and/or sediment (grain size 0.2 mm; high, intermediate, natural to 18 channels supplied with water from a nearby stream. Temperature was increased by 1.4°C in half the channels, simulating the loss of upstream and adjacent riparian shade. Sediment affected 93% of all biological response variables (either as an individual effect or via an interaction with another stressor generally in a negative manner, while nutrient enrichment affected 59% (mostly positive and raised temperature 59% (mostly positive. More of the algal components of the community responded to stressors acting individually than did invertebrate components, whereas pair-wise stressor interactions were more common in the invertebrate community. Stressors interacted often and in a complex manner, with interactions between sediment and temperature most common. Thus, the negative impact of high sediment on taxon richness of both algae and invertebrates was stronger at raised temperature, further reducing biodiversity. In addition, the decay rate of leaf material (strength loss accelerated with nutrient enrichment at ambient but not at raised temperature. A key implication of our findings for resource managers is that the removal of riparian shading from streams already subjected to high sediment inputs, or land-use changes that increase erosion or nutrient runoff in a landscape without riparian buffers, may have unexpected effects on stream health. We highlight the likely importance of intact or restored buffer

  19. Parent and Adolescent Agreement for Reports of Life Stressors.

    Science.gov (United States)

    Kushner, Shauna C; Tackett, Jennifer L

    2017-03-01

    In this article, we investigated the extent and nature of informant discrepancies on parent- and adolescent self-report versions of a checklist measuring youth exposure to life stressors. Specifically, we examined (a) mean-level differences, relative consistency, and consensus for family-level and youth-specific stressors and (b) the utility of parent-youth discrepancies in accounting for variance in youth temperament and psychopathology. Participants were 106 parent-child dyads (47 male, 59 female; 90.6% mothers) aged 13 to 18 years old ( M = 16.01, SD = 1.29). The results revealed evidence for both congruence and divergence in parent and youth reports, particularly with respect to respondents' accounts of youth-specific stressors. Discrepancies for youth-specific stressors were associated with adolescents' negative affectivity, surgency, effortful control, and internalizing problems. Discrepancies for youth stressors may therefore reveal individual differences in emotionality and self-regulation, thus reflecting meaningful variance in adolescents' functioning.

  20. Arsenic species in ecosystems affected by arsenic-rich spring water near an abandoned mine in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.T. [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of); Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, H.O., E-mail: dunee@kbsi.re.k [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, C. [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Woo, N.C., E-mail: ncwoo@yonsei.ac.k [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of)

    2009-12-15

    The objectives of this study were to quantitatively estimate the distribution of arsenic with its speciation and to identify potential pathways for transformation of arsenic species from samples of water, sediments, and plants in the ecosystem affected by the Cheongog Spring, where As(V) concentration reached levels up to 0.270 mg L{sup -1}. After flowing about 100 m downstream, the arsenic level showed a marked reduction to 0.044 mg L{sup -1} (about 84% removal) without noticeable changes in major water chemistry. The field study and laboratory hydroponic experiments with the dominant emergent plants along the creek (water dropwort and thunbergian smartweed) indicated that arsenic distribution, reduction, and speciation appear to be controlled by, (i) sorption onto stream sediments in exchangeable fractions, (ii) bioaccumulation by and possible release from emergent plants, and (iii) transformation of As(V) to As(III) and organic species through biological activities. - Biogeochemical reactions with emergent plants and sediments control the fate of arsenic along creeks originating from a high-As Spring.

  1. Stressors in Atopic Dermatitis.

    Science.gov (United States)

    Barilla, Steven; Felix, Kayla; Jorizzo, Joseph L

    2017-01-01

    As with other inflammatory skin disorders, atopic dermatitis has a tendency to cause stress and also be exacerbated by it. Patients with atopic dermatitis have several disease-associated stressors, some of which include physical discomfort due to itching and altered appearance due to flare-ups. These stressors have been shown to effect patients psychosocially by altering sleep patterns, decreasing self-esteem and interfering with interpersonal relationships. In combination with its direct effect on patients, atopic dermatitis also causes stress for parents and caregivers. Studies suggest that atopic dermatitis is strongly correlated with co-sleeping habits, which can negatively impact the health and mood of parents or caregivers. It has also been reported to interfere with the formation of a strong mother-child relationship. In order to optimize treatment for patients with atopic dermatitis, it is important to note the impact that it has on quality of life. By implementing patient counseling, sleep-targeted therapies, and the use of quality of life (QoL) indices, atopic dermatitis patients and caregivers have the potential to experience greater satisfaction with treatment.

  2. Occupational stressors in nursing

    Directory of Open Access Journals (Sweden)

    N. Nikpeyma

    2009-04-01

    Full Text Available Background and aimsNursing provides a wide range of potential workplace stressors as it is  a profession that requires a high level of skill, teamworking in a variety of situations and provision  of 24-hour delivery of care .Occupational stress is a major factor of Staff sickness an  absenteeism.This study investigates the main occupational stressors in nursing profession in the  hope of identification and reducing it.MethodsIn this study a questionnaire consisting of three parts:demoghraphic data,the nurses  background and questions about occupational stress from Revised index fulfilled by 140 nurses.ResultsLack of reward for work well done(48/6%, Heavy workload(46/4% ,lack of Participation in decisions (39/3% , poor Control of work place(38/4%and lack of job  development (36/4% have been the main sources of Occupational stress for nurses.chronic  diseases, Night Shift working and working hours were positively associated with occupstional  stress.Conclusion Analysis indicated that effects of work factors on occupational stress are more than demoghraphic data. The findings of this study can assist health service organisations to provide an attractive working climate in order to decrease side effects and consequences of occupational stress. Furthermore, understanding this situation can help to develop coping strategies in order to reduce work-related stress.

  3. Enduring the shipboard stressor complex: a systems approach.

    Science.gov (United States)

    Comperatore, Carlos A; Rivera, Pik Kwan; Kingsley, Leonard

    2005-06-01

    A high incidence of physiological and psychological stressors characterizes the maritime work environment in many segments of the commercial maritime industry and in the military. Traditionally, crewmembers work embedded in a complex of stressors. Stressors rarely act independently because most occur concurrently, simultaneously taxing physical and mental resources. Stressors such as extreme environmental temperatures, long work hours, heavy mental and physical workload, authoritative leadership, isolation from family and loved ones, lack of exercise, and unhealthy diets often combine to degrade crewmember health and performance, particularly on long voyages. This complex system of interacting stressors affects the ability of maritime crewmembers to maintain adequate levels of alertness and performance. An analytical systems approach methodology is described here as a viable method to identify workplace stressors and track their systemic interactions. A systems-based program for managing the stressor complex is then offered, together with the empirical research supporting its efficacy. Included is an example implementation of a stressor-control program aboard a U.S. Coast Guard cutter.

  4. Effects of ship-induced waves on aquatic ecosystems.

    Science.gov (United States)

    Gabel, Friederike; Lorenz, Stefan; Stoll, Stefan

    2017-12-01

    Most larger water bodies worldwide are used for navigation, and the intensity of commercial and recreational navigation is expected to further increase. Navigation profoundly affects aquatic ecosystems. To facilitate navigation, rivers are trained and developed, and the direct effects of navigation include chemical and biological impacts (e.g., inputs of toxic substances and dispersal of non-native species, respectively). Furthermore, propagating ships create hydrodynamic alterations, often simply summarized as waves. Although ship-induced waves are recognized as influential stressors, knowledge on their effects is poorly synthesized. We present here a review on the effects of ship-induced waves on the structure, function and services of aquatic ecosystems based on more than 200 peer reviewed publications and technical reports. Ship-induced waves act at multiple organizational levels and different spatial and temporal scales. All the abiotic and biotic components of aquatic ecosystems are affected, from the sediment and nutrient budget to the planktonic, benthic and fish communities. We highlight how the effects of ship-induced waves cascade through ecosystems and how different effects interact and feed back into the ecosystem finally leading to altered ecosystem services and human health effects. Based on this synthesis of wave effects, we discuss strategies for mitigation. This may help to develop scientifically based and target-oriented management plans for navigational waters that optimize abiotic and biotic integrity and their ecosystem services and uses. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Hemodialysis: stressors and coping strategies.

    Science.gov (United States)

    Ahmad, Muayyad M; Al Nazly, Eman K

    2015-01-01

    End-stage renal disease (ESRD) is an irreversible and life-threatening condition. In Jordan, the number of ESRD patients treated with hemodialysis is on the rise. Identifying stressors and coping strategies used by patients with ESRD may help nurses and health care providers to gain a clearer understanding of the condition of these patients and thus institute effective care planning. The purpose of this study was to identify stressors perceived by Jordanian patients on hemodialysis, and the coping strategies used by them. A convenience sample of 131 Jordanian men and women was recruited from outpatients' dialysis units in four hospitals. Stressors perceived by participants on hemodialysis and the coping strategies were measured using Hemodialysis Stressor Scale, and Ways of Coping Scale-Revised. Findings showed that patients on hemodialysis psychosocial stressors scores mean was higher than the physiological stressors mean. Positive reappraisal coping strategy had the highest mean among the coping strategies and the lowest mean was accepting responsibility. Attention should be focused towards the psychosocial stressors of patients on hemodialysis and also helping patients utilize the coping strategies that help to alleviate the stressors. The most used coping strategy was positive reappraisal strategy which includes faith and prayer.

  6. Longitudinal associations between stressors and work ability in hospital workers.

    Science.gov (United States)

    Carmen Martinez, Maria; da Silva Alexandre, Tiago; Dias de Oliveira Latorre, Maria do Rosario; Marina Fischer, Frida

    This study sought to assess associations between work stressors and work ability in a cohort (2009-2012) of 498 hospital workers. Time-dependent variables associated with the Work Ability Index (WAI) were evaluated using general linear mixed models. Analyses included effects of individual and work characteristics. Except for work demands, the work stressors (job control, social support, effort-reward imbalance, overcommitment and work-related activities that cause pain/injury) were associated with WAI (p work and morning shift work were associated with decreased WAI (p Work stressors negatively affected work ability over time independently of other variables.

  7. The Combined Effects of Daily Stressors and Major Life Events on Daily Subjective Ages.

    Science.gov (United States)

    Bellingtier, Jennifer A; Neupert, Shevaun D; Kotter-Grühn, Dana

    2017-07-01

    Stressors may be a contributing factor in determining how old an individual feels, looks, or would like to be. Currently, little research has been devoted to understanding the relationship between stressors and subjective age in older adults. We focus on the combined impact of major life-event stressors and daily stressors on multiple indicators of subjective age: felt age, ideal age, and look age. Furthermore, we examine the process by which daily stressors relate to subjective ages by testing whether positive affect, control, and negative affect mediate this relationship. Using a daily-diary design, the current study measured older adults' (60-96 years old) stressors, subjective ages, personal control, and affect. Felt, ideal, and look ages each demonstrated a unique pattern of interactions between daily stressors and major life-event stressors. Furthermore, our findings suggest that on the daily level, the relationship between stressors and felt age is mediated by negative affect but not by control and positive affect. Findings indicate the need to consider the broader contextual picture of stressors, as well as their differential impact on multiple indicators of subjective age. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Managing aquatic ecosystems and water resources under multiple stress--an introduction to the MARS project.

    Science.gov (United States)

    Hering, Daniel; Carvalho, Laurence; Argillier, Christine; Beklioglu, Meryem; Borja, Angel; Cardoso, Ana Cristina; Duel, Harm; Ferreira, Teresa; Globevnik, Lidija; Hanganu, Jenica; Hellsten, Seppo; Jeppesen, Erik; Kodeš, Vit; Solheim, Anne Lyche; Nõges, Tiina; Ormerod, Steve; Panagopoulos, Yiannis; Schmutz, Stefan; Venohr, Markus; Birk, Sebastian

    2015-01-15

    Water resources globally are affected by a complex mixture of stressors resulting from a range of drivers, including urban and agricultural land use, hydropower generation and climate change. Understanding how stressors interfere and impact upon ecological status and ecosystem services is essential for developing effective River Basin Management Plans and shaping future environmental policy. This paper details the nature of these problems for Europe's water resources and the need to find solutions at a range of spatial scales. In terms of the latter, we describe the aims and approaches of the EU-funded project MARS (Managing Aquatic ecosystems and water Resources under multiple Stress) and the conceptual and analytical framework that it is adopting to provide this knowledge, understanding and tools needed to address multiple stressors. MARS is operating at three scales: At the water body scale, the mechanistic understanding of stressor interactions and their impact upon water resources, ecological status and ecosystem services will be examined through multi-factorial experiments and the analysis of long time-series. At the river basin scale, modelling and empirical approaches will be adopted to characterise relationships between multiple stressors and ecological responses, functions, services and water resources. The effects of future land use and mitigation scenarios in 16 European river basins will be assessed. At the European scale, large-scale spatial analysis will be carried out to identify the relationships amongst stress intensity, ecological status and service provision, with a special focus on large transboundary rivers, lakes and fish. The project will support managers and policy makers in the practical implementation of the Water Framework Directive (WFD), of related legislation and of the Blueprint to Safeguard Europe's Water Resources by advising the 3rd River Basin Management Planning cycle, the revision of the WFD and by developing new tools for

  9. Seasonality and Management Affect Land Surface Temperature Differences Between Loblolly Pine and Switchgrass Ecosystems in Central Virginia

    Science.gov (United States)

    Ahlswede, B.; Thomas, R. Q.; O'Halloran, T. L.; Rady, J.; LeMoine, J.

    2017-12-01

    Changes in land-use and land management can have biogeochemical and biophysical effects on local and global climate. While managed ecosystems provide known food and fiber benefits, their influence on climate is less well quantified. In the southeastern United States, there are numerous types of intensely managed ecosystems but pine plantations and switchgrass fields represent two biogeochemical and biophysical extremes; a tall, low albedo forest with trees harvested after multiple decades vs. a short, higher albedo C4 grass field that is harvested annually. Despite the wide spread use of these ecosystems for timber and bioenergy, a quantitative, empirical evaluation of the net influence of these ecosystems on climate is lacking because it requires measuring both the greenhouse gas and energy balance of the ecosystems while controlling for the background weather and soil environment. To address this need, we established a pair of eddy flux towers in these ecosystems that are co-located (1.5 km apart) in Central Virginia and measured the radiative energy, non-radiative energy and carbon fluxes, along with associated biometeorology variables; the paired site has run since April 2016. During the first 1.5 years (two growing seasons), we found strong seasonality in the difference in surface temperature between the two ecosystems. In the growing seasons, both sites had similar surface temperature despite higher net radiation in pine. Following harvest of the switchgrass in September, the switchgrass temperatures increased relative to pine. In the winter, the pine ecosystem was warmer. We evaluate the drivers of these intra-annual dynamics and compare the climate influence of these biophysical differences to the differences in carbon fluxes between the sites using a suite of established climate regulation services metrics. Overall, our results show tradeoffs exist between the biogeochemical and biophysical climate services in managed ecosystems in the southeastern United

  10. Daily stressors and emotional reactivity in individuals with mild cognitive impairment and cognitively healthy controls.

    Science.gov (United States)

    Rickenbach, Elizabeth Hahn; Condeelis, Kristen L; Haley, William E

    2015-06-01

    Daily experiences of stress are common and have been associated with worse affect among older adults. People with mild cognitive impairment (PWMCI) have measurable memory deficits in between normal cognition and dementia and have been identified as having greater psychological distress than cognitively healthy older adults (CHOAs). Little is known about whether daily stressors contribute to distress among PWMCI. We hypothesized that compared with CHOAs, PWMCI would have higher daily negative affect and lower daily positive affect, report greater numbers and severity of daily stressors, and experience greater emotional reactivity to daily stressors. Fifteen clinically diagnosed PWMCI and 25 CHOAs completed daily reports of stressors, stressor severity, and positive and negative affect over an 8-day period. PWMCI reported higher daily negative affect, lower daily positive affect, and higher numbers and greater severity of memory stressors but did not differ from CHOAs in numbers or severity of general stressors. Cognitive status was a moderator of the daily stress-affect relationship. Days with greater numbers and severity of general daily stressors were associated with higher negative affect only for PWMCI. The numbers and severity of memory stressors were not associated with negative affect. In addition, more severe general daily stressors and memory stressors were associated with lower positive affect for all participants. Results suggest that PWMCI are less resilient in the face of daily stress than are CHOAs in terms of negative affect, perhaps because of declines in reserve capacity. The study presents a promising approach to understanding stress and coping in predementia states of cognition. (c) 2015 APA, all rights reserved.

  11. Biochemical leaf traits as indicators of tolerance potential in tree species from the Brazilian Atlantic Forest against oxidative environmental stressors.

    Science.gov (United States)

    Brandão, Solange E; Bulbovas, Patricia; Lima, Marcos E L; Domingos, Marisa

    2017-01-01

    The tolerance potential against the oxidative injury in native plants from forest ecosystems affected by environmental stressors depends on how efficiently they keep their pro-oxidant/antioxidant balance. Great variations in plant tolerance are expected, highlighting the higher relevance of measuring biochemical leaf trait indicators of oxidative injury in species with similar functions in the forest than in single species. The use of this functional approach seems very useful in the Brazilian Atlantic Forest because it still holds high plant diversity and was the focus of this study. We aimed at determining the tolerance potential of tree species from the Atlantic Forest remnants in SE Brazil against multiple oxidative environmental stressors. We assumed that pioneer tree species are more tolerant against oxidative stress than non-pioneer tree species and that their tolerance potential vary spatially in response to distinct combined effects of oxidative environmental stressors. The study was carried out in three Atlantic Forest remnants, which differ in physiognomy, species composition, climatic characteristics and air pollution exposure. Leaves of three pioneer and three non-pioneer species were collected from each forest remnant during wet (January 2015) and dry periods (June 2015), for analyses of non-enzymatic and enzymatic antioxidants and oxidative injury indicators. Both hypotheses were confirmed. The pioneer tree species displayed biochemical leaf traits (e.g. high levels of ascorbic acid, glutathione and carotenoids and lower lipid peroxidation) that indicate their higher potential tolerance against oxidative environmental stressors than non-pioneer species. The biochemical leaf traits of both successional groups of species varied between the forest remnants, in response to a linear combination of oxidative environmental stressors, from natural (relative humidity and temperature) and anthropogenic sources (ozone and nitrogen dioxide). Copyright © 2016

  12. Widespread local chronic stressors in Caribbean coastal habitats.

    Science.gov (United States)

    Chollett, Iliana; Collin, Rachel; Bastidas, Carolina; Cróquer, Aldo; Gayle, Peter M H; Jordán-Dahlgren, Eric; Koltes, Karen; Oxenford, Hazel; Rodriguez-Ramirez, Alberto; Weil, Ernesto; Alemu, Jahson; Bone, David; Buchan, Kenneth C; Creary Ford, Marcia; Escalante-Mancera, Edgar; Garzón-Ferreira, Jaime; Guzmán, Hector M; Kjerfve, Björn; Klein, Eduardo; McCoy, Croy; Potts, Arthur C; Ruíz-Rentería, Francisco; Smith, Struan R; Tschirky, John; Cortés, Jorge

    2017-01-01

    Coastal ecosystems and the livelihoods they support are threatened by stressors acting at global and local scales. Here we used the data produced by the Caribbean Coastal Marine Productivity program (CARICOMP), the longest, largest monitoring program in the wider Caribbean, to evidence local-scale (decreases in water quality) and global-scale (increases in temperature) stressors across the basin. Trend analyses showed that visibility decreased at 42% of the stations, indicating that local-scale chronic stressors are widespread. On the other hand, only 18% of the stations showed increases in water temperature that would be expected from global warming, partially reflecting the limits in detecting trends due to inherent natural variability of temperature data. Decreases in visibility were associated with increased human density. However, this link can be decoupled by environmental factors, with conditions that increase the flush of water, dampening the effects of human influence. Besides documenting environmental stressors throughout the basin, our results can be used to inform future monitoring programs, if the desire is to identify stations that provide early warning signals of anthropogenic impacts. All CARICOMP environmental data are now available, providing an invaluable baseline that can be used to strengthen research, conservation, and management of coastal ecosystems in the Caribbean basin.

  13. Hydraulic redistribution of soil water by roots affects whole-stand evapotranspiration and net ecosystem carbon exchange

    Science.gov (United States)

    J.-C. Domec; J.S. King; A. Noormets; E. Treasure; M.J. Gavazzi; G. Sun; S.G. McNulty

    2010-01-01

    Hydraulic redistribution (HR) of water via roots from moist to drier portions of the soil occurs in many ecosystems, potentially influencing both water use and carbon assimilation. By measuring soil water content, sap flow and eddy covariance, we investigated the temporal variability of HR in a loblolly pine (Pinus taeda) plantation during months of...

  14. Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

    NARCIS (Netherlands)

    Macfadyen, S.; Gibson, R.; Polaszek, A.; Morris, R.J.; Craze, P.G.; Planque, R.; Symondson, W.O.C.; Memmott, J.

    2009-01-01

    While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative

  15. Are rocky shore ecosystems affected by nutrient-enriched seawater? Some preliminary results from a mesocosm experiment

    NARCIS (Netherlands)

    Bokn, T.L.; Moy, F.E.; Christie, H.; Engelbert, S.; Karez, R.; Kersting, K.; Kraufvelin, P.; Lindblad, C.; Marba, N.; Pedersen, M.F.; Sorensen, K.

    2002-01-01

    The response of rocky shore ecosystems to increased nutrient availability was examined in eight land-based mesocosms designed for hard-bottom littoral communities built at Marine Research Station Solbergstrand (Norway). The average seawater volume in each basin was 9 m3 with an average water

  16. Environmental risk assessment for invasive alien species : A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    2017-01-01

    The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple snails

  17. Environmental risk assessment for invasive alien species: A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    Abstract The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple

  18. Untangling the effects of multiple human stressors and their impacts on fish assemblages in European running waters.

    Science.gov (United States)

    Schinegger, Rafaela; Palt, Martin; Segurado, Pedro; Schmutz, Stefan

    2016-12-15

    This work addresses human stressors and their impacts on fish assemblages at pan-European scale by analysing single and multiple stressors and their interactions. Based on an extensive dataset with 3105 fish sampling sites, patterns of stressors, their combination and nature of interactions, i.e. synergistic, antagonistic and additive were investigated. Geographical distribution and patterns of seven human stressor variables, belonging to four stressor groups (hydrological-, morphological-, water quality- and connectivity stressors), were examined, considering both single and multiple stressor combinations. To quantify the stressors' ecological impact, a set of 22 fish metrics for various fish assemblage types (headwaters, medium gradient rivers, lowland rivers and Mediterranean streams) was analysed by comparing their observed and expected response to different stressors, both acting individually and in combination. Overall, investigated fish sampling sites are affected by 15 different stressor combinations, including 4 stressors acting individually and 11 combinations of two or more stressors; up to 4 stressor groups per fish sampling site occur. Stressor-response analysis shows divergent results among different stressor categories, even though a general trend of decreasing ecological integrity with increasing stressor quantity can be observed. Fish metrics based on density of species 'intolerant to water quality degradation' and 'intolerant to oxygen depletion" responded best to single and multiple stressors and their interactions. Interactions of stressors were additive (40%), synergistic (30%) or antagonistic (30%), emphasizing the importance to consider interactions in multi-stressor analyses. While antagonistic effects are only observed in headwaters and medium-gradient rivers, synergistic effects increase from headwaters over medium gradient rivers and Mediterranean streams to large lowland rivers. The knowledge gained in this work provides a basis for

  19. Impacts of climate change on biodiversity, ecosystems, and ecosystem services: technical input to the 2013 National Climate Assessment

    Science.gov (United States)

    Staudinger, Michelle D.; Grimm, Nancy B.; Staudt, Amanda; Carter, Shawn L.; Stuart, F. Stuart; Kareiva, Peter; Ruckelshaus, Mary; Stein, Bruce A.

    2012-01-01

    Ecosystems, and the biodiversity and services they support, are intrinsically dependent on climate. During the twentieth century, climate change has had documented impacts on ecological systems, and impacts are expected to increase as climate change continues and perhaps even accelerates. This technical input to the National Climate Assessment synthesizes our scientific understanding of the way climate change is affecting biodiversity, ecosystems, ecosystem services, and what strategies might be employed to decrease current and future risks. Building on past assessments of how climate change and other stressors are affecting ecosystems in the United States and around the world, we approach the subject from several different perspectives. First, we review the observed and projected impacts on biodiversity, with a focus on genes, species, and assemblages of species. Next, we examine how climate change is affecting ecosystem structural elements—such as biomass, architecture, and heterogeneity—and functions—specifically, as related to the fluxes of energy and matter. People experience climate change impacts on biodiversity and ecosystems as changes in ecosystem services; people depend on ecosystems for resources that are harvested, their role in regulating the movement of materials and disturbances, and their recreational, cultural, and aesthetic value. Thus, we review newly emerging research to determine how human activities and a changing climate are likely to alter the delivery of these ecosystem services. This technical input also examines two cross-cutting topics. First, we recognize that climate change is happening against the backdrop of a wide range of other environmental and anthropogenic stressors, many of which have caused dramatic ecosystem degradation already. This broader range of stressors interacts with climate change, and complicates our abilities to predict and manage the impacts on biodiversity, ecosystems, and the services they support. The

  20. Assessing and managing stressors in a changing marine environment.

    Science.gov (United States)

    Chapman, Peter M

    2017-11-30

    We are facing a dynamic future in the face of multiple stressors acting individually and in combination: climate change; habitat change/loss; overfishing; invasive species; harmful algal blooms/eutrophication; and, chemical contaminants. Historic assessment and management approaches will be inadequate for addressing risks from climate change and other stressors. Wicked problems (non-linear, complex, competing risks and benefits, not easily solvable), will become increasingly common. We are facing irreversible changes to our planetary living conditions. Agreed protection goals and considering both the negatives (risks) and the positives (benefits) of all any and all actions are required, as is judicious and appropriate use of the Precautionary Principle. Researchers and managers need to focus on: determining tipping points (alternative stable points); maintaining ecosystem services; and, managing competing ecosystem services. Marine (and other) scientists are urged to focus their research on wicked problems to allow for informed decision-making on a planetary basis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Chemical and natural stressors combined:

    DEFF Research Database (Denmark)

    Gergs, André; Zenker, Armin; Grimm, Volker

    2013-01-01

    In addition to natural stressors, populations are increasingly exposed to chemical pollutants released into the environment. We experimentally demonstrate the loss of resilience for Daphnia magna populations that are exposed to a combination of natural and chemical stressors even though effects...... demonstrates that population size can be a poor endpoint for risk assessments of chemicals and that ignoring disturbance interactions can lead to severe underestimation of extinction risk...

  2. The Southern Ocean ecosystem under multiple climate change stresses--an integrated circumpolar assessment.

    Science.gov (United States)

    Gutt, Julian; Bertler, Nancy; Bracegirdle, Thomas J; Buschmann, Alexander; Comiso, Josefino; Hosie, Graham; Isla, Enrique; Schloss, Irene R; Smith, Craig R; Tournadre, Jean; Xavier, José C

    2015-04-01

    A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (Changes in iceberg impact resulting from further collapse of ice-shelves can potentially affect large parts of shelf and ephemerally in the off-shore regions. However, aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO. Direct and indirect impacts of various environmental changes to the three major habitats, sea-ice, pelagic and benthos and their biota are complex. The areas affected by environmental stressors range from 33% of the SO for a single stressor, 11% for two and 2% for three, to changes, and together cover almost 86% of the SO ecosystem. © 2014 John Wiley & Sons Ltd.

  3. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

    Science.gov (United States)

    Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

    2010-07-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

  4. Radiography student perceptions of clinical stressors.

    Science.gov (United States)

    Mason, Starla L

    2006-01-01

    Technological change and the increasingly rapid pace of life in the United States and globally have contributed to increased levels of stress and burnout experienced by workers and their families. Although studies are available on the levels of workplace stress and burnout affecting radiographers, little to no research has been conducted to assess the stressors encountered by radiography students in the clinical environment. This study was designed to pinpoint the primary sources of stress for radiography students and to determine the most effective measures to alleviate the stress that students experience in the clinical environment. It also sought to identify the clinical activities and practices that enhance learning. A convenience sample of radiography students attending an Association of Collegiate Educators in Radiologic Technology meeting was surveyed. Students were asked to rank their greatest stressors in the clinical environment, the most desired qualities in a clinical instructor and clinical environment, and the clinical practices and activities that best enhance their learning. Descriptive statistics were used to report the results. Data were collected for 82 first-year and second-year students. Students identified 7 primary clinical stressors: fear of making a mistake/repeat, feeling unprepared/inexperienced, intimidation by staff and by instructors, difficult/critical patients, hurtful criticism, too much supervision and negative responses to questions/requests for help. Students indicated that more frequent feedback, availability of the clinical instructor and other staff, assurance that mistakes happen and the opportunity to make mistakes were clinical practices that eased stress. The majority of students cited hands-on learning and repetition as the clinical activities that most reinforced their learning. Summary Radiography students in this survey experience some of the same clinical stressors as radiographers and other allied health workers

  5. Daily Emotional and Physical Reactivity to Stressors Among Widowed and Married Older Adults

    Science.gov (United States)

    2014-01-01

    Objectives. Widowhood may result in declines in health and potentially stressful changes to daily routines. However, little research has examined how daily stressors contribute to physical and emotional well-being in widowhood. The objectives of the current study were to examine daily stressor exposure and reactivity in widowed versus married older adults. Method. Participants included all 100 widowed and 342 married adults aged 65 and older from the National Study of Daily Experiences, a daily diary study from the second wave of the Midlife in the United States. Daily stressors were measured using the Daily Inventory of Stressful Events; multilevel modeling assessed daily reactivity to stressors using daily negative affect (emotional reactivity) and daily physical symptoms (physical reactivity) as outcomes. Results. Married participants reported more stressors in general, and specifically more interpersonal stressors (e.g., arguments). Both married and widowed participants were reactive to daily stressors. Married participants were physically and emotionally reactive to interpersonal stressors. Widowed participants were more physically reactive to home-related stressors. Discussion. Attention to the types of daily stressors that widowed older adults experience in daily life and the potential physical effects of daily stressors during widowhood may help to alleviate some of the physical distress that widowed older adults may experience. PMID:23685921

  6. Daily emotional and physical reactivity to stressors among widowed and married older adults.

    Science.gov (United States)

    Hahn, Elizabeth A; Cichy, Kelly E; Small, Brent J; Almeida, David M

    2014-01-01

    Widowhood may result in declines in health and potentially stressful changes to daily routines. However, little research has examined how daily stressors contribute to physical and emotional well-being in widowhood. The objectives of the current study were to examine daily stressor exposure and reactivity in widowed versus married older adults. Participants included all 100 widowed and 342 married adults aged 65 and older from the National Study of Daily Experiences, a daily diary study from the second wave of the Midlife in the United States. Daily stressors were measured using the Daily Inventory of Stressful Events; multilevel modeling assessed daily reactivity to stressors using daily negative affect (emotional reactivity) and daily physical symptoms (physical reactivity) as outcomes. Married participants reported more stressors in general, and specifically more interpersonal stressors (e.g., arguments). Both married and widowed participants were reactive to daily stressors. Married participants were physically and emotionally reactive to interpersonal stressors. Widowed participants were more physically reactive to home-related stressors. Attention to the types of daily stressors that widowed older adults experience in daily life and the potential physical effects of daily stressors during widowhood may help to alleviate some of the physical distress that widowed older adults may experience.

  7. Identification and ranking of environmental threats with ecosystem vulnerability distributions.

    Science.gov (United States)

    Zijp, Michiel C; Huijbregts, Mark A J; Schipper, Aafke M; Mulder, Christian; Posthuma, Leo

    2017-08-24

    Responses of ecosystems to human-induced stress vary in space and time, because both stressors and ecosystem vulnerabilities vary in space and time. Presently, ecosystem impact assessments mainly take into account variation in stressors, without considering variation in ecosystem vulnerability. We developed a method to address ecosystem vulnerability variation by quantifying ecosystem vulnerability distributions (EVDs) based on monitoring data of local species compositions and environmental conditions. The method incorporates spatial variation of both abiotic and biotic variables to quantify variation in responses among species and ecosystems. We show that EVDs can be derived based on a selection of locations, existing monitoring data and a selected impact boundary, and can be used in stressor identification and ranking for a region. A case study on Ohio's freshwater ecosystems, with freshwater fish as target species group, showed that physical habitat impairment and nutrient loads ranked highest as current stressors, with species losses higher than 5% for at least 6% of the locations. EVDs complement existing approaches of stressor assessment and management, which typically account only for variability in stressors, by accounting for variation in the vulnerability of the responding ecosystems.

  8. Forest ecosystem services affected by natural disturbances, climate and land-use changes in the Tatra Mountains

    Czech Academy of Sciences Publication Activity Database

    Fleischer, P.; Pichler, V.; Holko, L.; Fleischer Jr., P.; Máliš, F.; Gömöryová, E.; Cudlín, Pavel; Holeksa, J.; Michalová, Z.; Homolová, Z.; Škvarenina, J.; Střelcová, K.; Hlaváč, P.

    2017-01-01

    Roč. 73, 1-2 (2017), s. 57-71 ISSN 0936-577X R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Forest ecosystem state * Bark beetle outbreak * Long-term research Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.578, year: 2016

  9. Forest type effects on the retention of radiocesium in organic layers of forest ecosystems affected by the Fukushima nuclear accident

    Science.gov (United States)

    Koarashi, Jun; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Sanada, Yukihisa

    2016-12-01

    The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137Cs remained in the organic layers, with an ecological half-life of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.

  10. Multiple stressors for oceanic primary production

    KAUST Repository

    Agusti, Susana

    2015-12-15

    Marine ecosystems are increasingly exposed to stress factors of anthropogenic origin that change their function, structure and services they deliver society. Climate change occurs simultaneously with other changes in the environment acting jointly in a context of global environmental change. For oceanic phytoplankton communities, the research conducted so far has identified stress factors associated with global change and their impact individually (warming, acidification, increased UVB radiation, pollutants). But when several stressors act simultaneously interactions and responses are not equal to the sum of individual impacts, but may have synergistic effects (the effects are multiplied) or antagonistic (cancel out the effects) that hinder predictions of the vulnerability of ecosystems to global change. Here we will examine the vulnerability of oceanic primary producers to the accumulation of different stressors associated with global change. The trend for autotrophic picoplankton to increase with temperature in the ocean has led to predictions that autotrophic picoplankton abundance will increase with warming. However, it is documented a trend towards a decline in productivity, due to declined autotroph biomass and production with warming and the associated stratification in the subtropical ocean. Models predicting an increase in abundance are in contradiction with the reported decrease in productivity in several oceanic areas, and associate oligotrophication. Here we perform a global study to analyze the relationships of autotrophic picoplankton with oceanic temperature, nutrients, underwater light and ultraviolet B (UVB) radiation, and productivity. We built a model to project the future changes of autotrophic picoplankton considering multiple environmental changes in future climate scenarios for the subtropical gyres. We considered increased water temperature, and associated changes in productivity and underwater light and UVB. The model show that warming and

  11. Multiple stressors for oceanic primary production

    KAUST Repository

    Agusti, Susana; Llabré s, Moira; Lubiá n, Luis M.; Moreno-Ostos, Enrique; Estrada, Marta; Duarte, Carlos M.; Cerezo, Maria I.

    2015-01-01

    Marine ecosystems are increasingly exposed to stress factors of anthropogenic origin that change their function, structure and services they deliver society. Climate change occurs simultaneously with other changes in the environment acting jointly in a context of global environmental change. For oceanic phytoplankton communities, the research conducted so far has identified stress factors associated with global change and their impact individually (warming, acidification, increased UVB radiation, pollutants). But when several stressors act simultaneously interactions and responses are not equal to the sum of individual impacts, but may have synergistic effects (the effects are multiplied) or antagonistic (cancel out the effects) that hinder predictions of the vulnerability of ecosystems to global change. Here we will examine the vulnerability of oceanic primary producers to the accumulation of different stressors associated with global change. The trend for autotrophic picoplankton to increase with temperature in the ocean has led to predictions that autotrophic picoplankton abundance will increase with warming. However, it is documented a trend towards a decline in productivity, due to declined autotroph biomass and production with warming and the associated stratification in the subtropical ocean. Models predicting an increase in abundance are in contradiction with the reported decrease in productivity in several oceanic areas, and associate oligotrophication. Here we perform a global study to analyze the relationships of autotrophic picoplankton with oceanic temperature, nutrients, underwater light and ultraviolet B (UVB) radiation, and productivity. We built a model to project the future changes of autotrophic picoplankton considering multiple environmental changes in future climate scenarios for the subtropical gyres. We considered increased water temperature, and associated changes in productivity and underwater light and UVB. The model show that warming and

  12. Reactive nitrogen impacts on ecosystem services

    Science.gov (United States)

    The Ecosystem Services Research Program (ESRP) is a new, multi-year research initiative under development by the Environmental Protection Agency (EPA). As one of its components, ESRP has chosen to focus on reactive Nitrogen (Nr) for stressor-specific ecosystem research through a...

  13. Termites create spatial structure and govern ecosystem function by affecting N2 fixation in an East African savanna.

    Science.gov (United States)

    Fox-Dobbs, Kena; Doak, Daniel F; Brody, Alison K; Palmer, Todd M

    2010-05-01

    The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the 15N natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence >50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure.

  14. A review of hydrological and chemical stressors in the Adige catchment and its ecological status.

    Science.gov (United States)

    Chiogna, Gabriele; Majone, Bruno; Cano Paoli, Karina; Diamantini, Elena; Stella, Elisa; Mallucci, Stefano; Lencioni, Valeria; Zandonai, Fabiana; Bellin, Alberto

    2016-01-01

    Quantifying the effects of multiple stressors on Alpine freshwater ecosystems is challenging, due to the lack of tailored field campaigns for the contemporaneous measurement of hydrological, chemical and ecological parameters. Conducting exhaustive field campaigns is costly and hence most of the activities so far have been performed addressing specific environmental issues. An accurate analysis of existing information is therefore useful and necessary, to identify stressors that may act in synergy and to design new field campaigns. We present an extended review of available studies and datasets concerning the hydrological, chemical and ecological status of the Adige, which is the second longest river and the third largest river basin in Italy. The most relevant stressors are discussed in the light of the information extracted from a large number of studies. The detailed analysis of these studies identified that hydrological alterations caused by hydropower production are the main source of stress for the freshwater ecosystems in the Adige catchment. However, concurrent effects with other stressors, such as the release of pollutants from waste water treatment plants or from agricultural and industrial activities, have not been explored at depth, so far. A wealth of available studies address a single stressor separately without exploring their concurrent effect. It is concluded that a combination of extended experimental field campaigns, focusing on the coupled effects of multiple stressors, and modeling activities is highly needed in order to quantify the impact of the multifaceted human pressures on freshwater ecosystems in the Adige river. Copyright © 2015. Published by Elsevier B.V.

  15. Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

    Science.gov (United States)

    Macfadyen, Sarina; Gibson, Rachel; Polaszek, Andrew; Morris, Rebecca J; Craze, Paul G; Planqué, Robert; Symondson, William O C; Memmott, Jane

    2009-03-01

    While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative food webs from 10 replicate pairs of organic and conventional farms showed that organic farms have significantly more species at three trophic levels (plant, herbivore and parasitoid) and significantly different network structure. Herbivores on organic farms were attacked by more parasitoid species on organic farms than on conventional farms. However, differences in network structure did not translate into differences in robustness to simulated species loss and we found no difference in percentage parasitism (natural pest control) across a variety of host species. Furthermore, a manipulative field experiment demonstrated that the higher species richness of parasitoids on the organic farms did not increase mortality of a novel herbivore used to bioassay ecosystem service. The explanation for these differences is likely to include inherent differences in management strategies and landscape structure between the two farming systems.

  16. Using ecological production functions to link ecological processes to ecosystem services.

    Science.gov (United States)

    Ecological production functions (EPFs) link ecosystems, stressors, and management actions to ecosystem services (ES) production. Although EPFs are acknowledged as being essential to improve environmental management, their use in ecological risk assessment has received relatively ...

  17. The Interactive Effect of Multiple Stressors on Crustacean Zooplankton Communities in Montane Lakes

    Science.gov (United States)

    Brittain, Jeffrey T.; Strecker, Angela L.

    2018-02-01

    Nonnative fish introductions have altered thousands of naturally fishless montane lakes, resulting in cascading food web repercussions. Nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of freshwater ecosystems, which may affect the abundance and composition of planktonic communities. This study identified responses of zooplankton communities from two lakes (fish present versus absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance of acidification and eutrophication via nitrogen addition in mesocosms. Zooplankton communities from lakes with different food web structure (i.e., fish present or absent) responded differently to the singular effects of acid and nitrogen addition. For instance, zooplankton biomass decreased in the acid treatment of the fishless lake experiment, but increased in response to acid in the fish-present experiment. In contrast, the combination of acid and nitrogen often resulted in weak responses for both lake types, resulting in nonadditive effects, i.e., the net effect of the stressors was in the opposite direction than predicted, which is known as a reversal or "ecological surprise." This experiment demonstrates the difficulty in predicting the interactive effects of multiple stressors on aquatic communities, which may pose significant challenges for habitat restoration through fish removal.

  18. The role of recurrent disturbances for ecosystem multifunctionality

    OpenAIRE

    Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf; Lukkari, Kaarina; Norkko, Alf

    2013-01-01

    Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in respons...

  19. Evaluation Of Batu Bumbun Sanctuary Ecosystem And Management Strategy Affected By Climate Change In Mahakam Watershed Kutai Kartanegara Indonesia

    Directory of Open Access Journals (Sweden)

    Lariman

    2015-08-01

    Full Text Available Batu Bumbun Sanctuary Middle Mahakam Lake is very important for the fishermen community and Mahakam Irrawaddy Dolphin life concerned to its function as the source of fish and as the feeding ground of Irrawaddy Dolphin Orcaella brevirostris. The changes in the forest function and the climate such as rainfall and water surfaces are predicted to have caused suppression in the ecosystem of Batu Bumbun Sanctuary. The aim of this study is to evaluate the current ecosystem changes of Batu Bumbun Sanctuary and suggest a suitable management strategy as a way to conserve its function. The research was conducted during the dry season April June and rainy season November December 2014 by using survey methods. The measured parameters were including water quality DO pH temperature TSS TDS alkalinity and clarity vegetation composition rainfall water surface elevation and sediment. The data of fish community were analysed by using Shanon-Wiener index. The result showed that 1 The current condition of Batu Bumbun biophysical ecosystem has been experiencing a heavy degradation showed by a high fluctuation of the water surface in two extreme seasons such as the flood in rainy seasons and silt up in the dry season. 2 The vegetation composition in the riverbanks was composed of five species including Bungur Lagerstroemia speciosa Rambai Punai Chaetocarpus Castano carpus Kendikara Dillenia excelsa Kademba Mytragina speciosa and Rengas Gluta renghas. The dominant tree species was Putat Barringtonia asiatica and Perupuk Lophopetalum javanicum. 3 Batu Bumbun Sanctuary has been experiencing a heavy siltation caused by silt material that piles up the weeds during the rainy season. Since 1985 Batu Bumbun was predicted to have rates of silting around 8 cmyear. From those result it can be concluded that Batu Bumbun has been experiencing a heavy degradation showed by a high fluctuation of water surface vegetation composition and heavy siltation. Then the most suitable

  20. Associations among daily stressors and salivary cortisol: findings from the National Study of Daily Experiences.

    Science.gov (United States)

    Stawski, Robert S; Cichy, Kelly E; Piazza, Jennifer R; Almeida, David M

    2013-11-01

    While much research has focused on linking stressful experiences to emotional and biological reactions in laboratory settings, there is an emerging interest in extending these examinations to field studies of daily life. The current study examined day-to-day associations among naturally occurring daily stressors and salivary cortisol in a national sample of adults from the second wave of the National Study of Daily Experiences (NSDE). A sample of 1694 adults (age=57, range=33-84; 44% male) completed telephone interviews detailing their stressors and emotions on eight consecutive evenings. Participants also provided saliva samples upon waking, 30min post-waking, before lunch and before bed, on four consecutive interview days resulting in 5995 days of interview/cortisol data. Analyses revealed three main findings. First, cortisol AUC was significantly higher on stressor days compared to stressor-free days, particularly for arguments and overloads at home, suggesting that daily stressors are associated with increased cortisol output, but that not all daily stressors have such an influence. Second, individuals reporting a greater frequency of stressor days also exhibited a steeper diurnal cortisol slope. Finally, daily stressor-cortisol associations were unaltered after adjustment for daily negative affect and physical symptoms. Our discussion focuses on the influence of naturally occurring daily stressors on daily cortisol and the role of daily diary approaches for studying healthy cortisol responses to psychosocial stressors outside of traditional laboratory settings. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Associations among Daily Stressors and Salivary Cortisol: Findings from the National Study of Daily Experiences

    Science.gov (United States)

    Stawski, Robert S.; Cichy, Kelly E.; Piazza, Jennifer R.; Almeida, David M.

    2013-01-01

    While much research has focused on linking stressful experiences to emotional and biological reactions in laboratory settings, there is an emerging interest in extending these examinations to field studies of daily life. The current study examined day-to-day associations among naturally-occurring daily stressors and salivary cortisol in a national sample of adults from the second wave of the National Study of Daily Experiences (NSDE). A sample of 1,694 adults (Age=57, Range=33–84; 44% male) completed telephone interviews detailing their stressors and emotions on eight consecutive evenings. Participants also provided saliva samples upon waking, 30 minutes post-waking, before lunch and before bed, on four consecutive interview days resulting in 5,995 days of interview/cortisol data. Analyses revealed three main findings. First, cortisol AUC was significantly higher on stressor days compared to stressor-free days, particularly for arguments and overloads at home, suggesting that daily stressors are associated with increased cortisol output, but that not all daily stressors have such an influence. Second, individuals reporting a greater frequency of stressor days also exhibited a steeper diurnal cortisol slope. Finally, daily stressor-cortisol associations were unaltered after adjustment for daily negative affect and physical symptoms. Our discussion focuses on the influence of naturally-occurring daily stressors on daily cortisol and the role of daily diary approaches for studying healthy cortisol responses to psychosocial stressors outside of traditional laboratory settings. PMID:23856186

  2. A comparison of metrics to evaluate the effects of hydro-facility passage stressors on fish

    Energy Technology Data Exchange (ETDEWEB)

    Colotelo, Alison H.; Goldman, Amy E.; Wagner, Katie A.; Brown, Richard S.; Deng, Z. Daniel; Richmond, Marshall C.

    2017-03-01

    Hydropower is the most common form of renewable energy, and countries worldwide are considering expanding hydropower to new areas. One of the challenges of hydropower deployment is mitigation of the environmental impacts including water quality, habitat alterations, and ecosystem connectivity. For fish species that inhabit river systems with hydropower facilities, passage through the facility to access spawning and rearing habitats can be particularly challenging. Fish moving downstream through a hydro-facility can be exposed to a number of stressors (e.g., rapid decompression, shear forces, blade strike and collision, and turbulence), which can all affect fish survival in direct and indirect ways. Many studies have investigated the effects of hydro-turbine passage on fish; however, the comparability among studies is limited by variation in the metrics and biological endpoints used. Future studies investigating the effects of hydro-turbine passage should focus on using metrics and endpoints that are easily comparable. This review summarizes four categories of metrics that are used in fisheries research and have application to hydro-turbine passage (i.e., mortality, injury, molecular metrics, behavior) and evaluates them based on several criteria (i.e., resources needed, invasiveness, comparability among stressors and species, and diagnostic properties). Additionally, these comparisons are put into context of study setting (i.e., laboratory vs. field). Overall, injury and molecular metrics are ideal for studies in which there is a need to understand the mechanisms of effect, whereas behavior and mortality metrics provide information on the whole body response of the fish. The study setting strongly influences the comparability among studies. In laboratory-based studies, stressors can be controlled by both type and magnitude, allowing for easy comparisons among studies. In contrast, field studies expose fish to realistic passage environments but the comparability is

  3. Affect

    NARCIS (Netherlands)

    Cetinic, M.; Diamanti, J.; Szeman, I.; Blacker, S.; Sully, J.

    2017-01-01

    This chapter historicizes four divergent but historically contemporaneous genres of affect theory – romantic, realist, speculative, and materialist. While critics credited with the turn to affect in the 1990s wrote largely in the wake of poststructuralism from the perspective of gender and queer

  4. The EBD Teacher Stressors Questionnaire.

    Science.gov (United States)

    Center, David B.; Steventon, Candace

    2001-01-01

    Two studies examined the validity of a self-report instrument that assesses occupational stressors in teachers of students with emotional and behavioral disorders (EBD). Differences were found in the stress management resources of low and high scoring EBD teachers on the measure and between scores of EBD and general education teachers, although…

  5. Perceived neighborhood characteristics predict severity and emotional response to daily stressors.

    Science.gov (United States)

    Scott, Stacey B; Munoz, Elizabeth; Mogle, Jacqueline A; Gamaldo, Alyssa A; Smyth, Joshua M; Almeida, David M; Sliwinski, Martin J

    2018-03-01

    Neighborhood characteristics may influence health and well-being outcomes through stressors in daily life. This study tested whether a varied set of perceived characteristics of neighborhood (i.e., social cohesion, safety, aesthetic quality, violence) predicted stressor frequency and severity as well as negative emotional responses to stressors. We predicted greater reported cohesion and safety and less violence would be associated with less frequent stressor exposure and severity and less intense negative affect following stressors; we conducted subsequent tests of neighborhood aesthetic quality as a predictor. Participants (n = 233, age 25-65 years) were residents in a socio-economically, racially, and ethnically diverse zip code in Bronx, New York, most who participated in the Effects of Stress on Cognitive Aging, Physiology and Emotion study between 2012 and 2013. They provided demographic information and neighborhood ratings, then participated in the EMA protocol in which they completed brief smartphone surveys of current negative affect and stressor exposure, severity, and recency, five times daily for 14 days. No coded neighborhood characteristic was related to the frequency of stressors. Individuals who reported greater neighborhood violence, however, rated their stressors as more severe. Individuals rating their neighborhood lower in safety or aesthetic quality, or higher in violence, had greater negative affect following stressors. Even among people living within the same zip code, individual differences in perceptions of neighborhood predict how stressful they appraised stressors in daily life to be and how much negative affect they reported following stressors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Scorched Earth: how will changes in the strength of the vegetation sink to ozone deposition affect human health and ecosystems?

    Directory of Open Access Journals (Sweden)

    L. D. Emberson

    2013-07-01

    Full Text Available This study investigates the effect of ozone (O3 deposition on ground level O3 concentrations and subsequent human health and ecosystem risk under hot summer "heat wave" type meteorological events. Under such conditions, extended drought can effectively "turn off" the O3 vegetation sink leading to a substantial increase in ground level O3 concentrations. Two models that have been used for human health (the CMAQ chemical transport model and ecosystem (the DO3SE O3 deposition model risk assessment are combined to provide a powerful policy tool capable of novel integrated assessments of O3 risk using methods endorsed by the UNECE Convention on Long-Range Transboundary Air Pollution. This study investigates 2006, a particularly hot and dry year during which a heat wave occurred over the summer across much of the UK and Europe. To understand the influence of variable O3 dry deposition three different simulations were investigated during June and July: (i actual conditions in 2006, (ii conditions that assume a perfect vegetation sink for O3 deposition and (iii conditions that assume an extended drought period that reduces the vegetation sink to a minimum. The risks of O3 to human health, assessed by estimating the number of days during which running 8 h mean O3 concentrations exceeded 100 μg m−3, show that on average across the UK, there is a difference of 16 days exceedance of the threshold between the perfect sink and drought conditions. These average results hide local variation with exceedances between these two scenarios reaching as high as 20 days in the East Midlands and eastern UK. Estimates of acute exposure effects show that O3 removed from the atmosphere through dry deposition during the June and July period would have been responsible for approximately 460 premature deaths. Conversely, reduced O3 dry deposition will decrease the amount of O3 taken up by vegetation and, according to flux-based assessments of vegetation damage, will lead

  7. Predominant Non-additive Effects of Multiple Stressors on Autotroph C:N:P Ratios Propagate in Freshwater and Marine Food Webs

    Science.gov (United States)

    Villar-Argaiz, Manuel; Medina-Sánchez, Juan M.; Biddanda, Bopaiah A.; Carrillo, Presentación

    2018-01-01

    A continuing challenge for scientists is to understand how multiple interactive stressor factors affect biological interactions, and subsequently, ecosystems–in ways not easily predicted by single factor studies. In this review, we have compiled and analyzed available research on how multiple stressor pairs composed of temperature (T), light (L), ultraviolet radiation (UVR), nutrients (Nut), carbon dioxide (CO2), dissolved organic carbon (DOC), and salinity (S) impact the stoichiometry of autotrophs which in turn shapes the nature of their ecological interactions within lower trophic levels in streams, lakes and oceans. Our analysis from 66 studies with 320 observations of 11 stressor pairs, demonstrated that non-additive responses predominate across aquatic ecosystems and their net interactive effect depends on the stressor pair at play. Across systems, there was a prevalence of antagonism in freshwater (60–67% vs. 47% in marine systems) compared to marine systems where synergism was more common (49% vs. 33–40% in freshwaters). While the lack of data impeded comparisons among all of the paired stressors, we found pronounced system differences for the L × Nut interactions. For this interaction, our data for C:P and N:P is consistent with the initial hypothesis that the interaction was primarily synergistic in the oceans, but not for C:N. Our study found a wide range of variability in the net effects of the interactions in freshwater systems, with some observations supporting antagonism, and others synergism. Our results suggest that the nature of the stressor pairs interactions on C:N:P ratios regulates the “continuum” commensalistic-competitive-predatory relationship between algae and bacteria and the food chain efficiency at the algae-herbivore interface. Overall, the scarce number of studies with even more fewer replications in each study that are available for freshwater systems have prevented a more detailed, insightful analysis. Our findings

  8. Predominant Non-additive Effects of Multiple Stressors on Autotroph C:N:P Ratios Propagate in Freshwater and Marine Food Webs

    Directory of Open Access Journals (Sweden)

    Manuel Villar-Argaiz

    2018-01-01

    Full Text Available A continuing challenge for scientists is to understand how multiple interactive stressor factors affect biological interactions, and subsequently, ecosystems–in ways not easily predicted by single factor studies. In this review, we have compiled and analyzed available research on how multiple stressor pairs composed of temperature (T, light (L, ultraviolet radiation (UVR, nutrients (Nut, carbon dioxide (CO2, dissolved organic carbon (DOC, and salinity (S impact the stoichiometry of autotrophs which in turn shapes the nature of their ecological interactions within lower trophic levels in streams, lakes and oceans. Our analysis from 66 studies with 320 observations of 11 stressor pairs, demonstrated that non-additive responses predominate across aquatic ecosystems and their net interactive effect depends on the stressor pair at play. Across systems, there was a prevalence of antagonism in freshwater (60–67% vs. 47% in marine systems compared to marine systems where synergism was more common (49% vs. 33–40% in freshwaters. While the lack of data impeded comparisons among all of the paired stressors, we found pronounced system differences for the L × Nut interactions. For this interaction, our data for C:P and N:P is consistent with the initial hypothesis that the interaction was primarily synergistic in the oceans, but not for C:N. Our study found a wide range of variability in the net effects of the interactions in freshwater systems, with some observations supporting antagonism, and others synergism. Our results suggest that the nature of the stressor pairs interactions on C:N:P ratios regulates the “continuum” commensalistic-competitive-predatory relationship between algae and bacteria and the food chain efficiency at the algae-herbivore interface. Overall, the scarce number of studies with even more fewer replications in each study that are available for freshwater systems have prevented a more detailed, insightful analysis. Our

  9. Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO(2) enrichment.

    Science.gov (United States)

    Pritchard, S G.; Davis, M A.; Mitchell, R J.; Prior, S A.; Boykin, D L.; Rogers, H H.; Runion, G B.

    2001-08-01

    Differential responses to elevated atmospheric CO(2) concentration exhibited by different plant functional types may alter competition for above- and belowground resources in a higher CO(2) world. Because C allocation to roots is often favored over C allocation to shoots in plants grown with CO(2) enrichment, belowground function of forest ecosystems may change significantly. We established an outdoor facility to examine the effects of elevated CO(2) on root dynamics in artificially constructed communities of five early successional forest species: (1) a C(3) evergreen conifer (longleaf pine, Pinus palustris Mill.); (2) a C(4) monocotyledonous bunch grass (wiregrass, Aristida stricta Michx.); (3) a C(3) broadleaf tree (sand post oak, Quercus margaretta); (4) a C(3) perennial herbaceous legume (rattlebox, Crotalaria rotundifolia Walt. ex Gemel); and (5) an herbaceous C(3) dicotyledonous perennial (butterfly weed, Asclepias tuberosa L.). These species are common associates in early successional longleaf pine savannahs throughout the southeastern USA and represent species that differ in life-form, growth habit, physiology, and symbiotic relationships. A combination of minirhizotrons and soil coring was used to examine temporal and spatial rooting dynamics from October 1998 to October 1999. CO(2)-enriched plots exhibited 35% higher standing root crop length, 37% greater root length production per day, and 47% greater root length mortality per day. These variables, however, were enhanced by CO(2) enrichment only at the 10-30 cm depth. Relative root turnover (flux/standing crop) was unchanged by elevated CO(2). Sixteen months after planting, root biomass of pine was 62% higher in elevated compared to ambient CO(2) plots. Conversely, the combined biomass of rattlebox, wiregrass, and butterfly weed was 28% greater in ambient compared to high CO(2) plots. There was no difference in root biomass of oaks after 16 months of exposure to elevated CO(2). Using root and shoot

  10. Implications for environmental health of multiple stressors

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, Colin

    2009-01-01

    Recent insights into the mechanisms underlying the biological effects of low dose effects of ionising radiation have revealed that similar mechanisms can be induced by chemical stressors in the environment. This means that interactions between radiation and chemicals are likely and that the outcomes following mixed exposures to radiation and chemicals may not be predictable for human health, by consideration of single agent effects. Our understanding of the biological effects of low dose exposure has undergone a major paradigm shift. We now possess technologies which can detect very subtle changes in cells due to small exposures to radiation or other pollutants. We also understand much more now about cell communication, systems biology and the need to consider effects of low dose exposure at different hierarchical levels of organisation from molecules up to and including ecosystems. Furthermore we understand, at least in part, some of the mechanisms which drive low dose effects and which perpetuate these not only in the exposed organism but also in its progeny and in certain cases, its kin. This means that previously held views about safe doses or lack of harmful effects cannot be sustained. The International Commission on Radiological Protection (ICRP) and all national radiation and environmental protection organisations have always accepted a theoretical risk and have applied the precautionary principle and the LNT (linear-non-threshold) model which basically says that there is no safe dose of radiation. Therefore even in the absence of visible effects, exposure of people to radiation is strictly limited. This review will consider the historical context and the new discoveries and will focus on evidence for emergent effects after mixed exposures to combined stressors which include ionising radiation. The implications for regulation of low dose exposures to protect human health and environmental security will be discussed.

  11. ECOSYSTEM SERVICES AND BEYOND: INTEGRATION OF ECOSYSTEM SCIENCE AND MULTIMEDIA EXPOSURE MODELING FOR ENVIRONMENTAL PROTECTION

    Science.gov (United States)

    Decision-making for ecosystem protection and resource management requires an integrative science and technology applied with a sufficiently comprehensive systems approach. Single media (e.g., air, soil and water) approaches that evaluate aspects of an ecosystem in a stressor-by-...

  12. Millennium Ecosystem Assessment: MA Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — The Millennium Ecosystem Assessment: MA Ecosystems provides data and information on the extent and classification of ecosystems circa 2000, including coastal,...

  13. Cross-Sectoral Resource Management: How Forest Management Alternatives Affect the Provision of Biomass and Other Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Susanne Frank

    2015-02-01

    Full Text Available Integrated forest management is faced with the challenge that the contribution of forests to economic and ecological planning targets must be assessed in a socio-ecological system context. This paper introduces a way to model spatio-temporal dynamics of biomass production at a regional scale in order to derive land use strategies that enhance biomass provision and avoid trade-offs for other ecosystem services. The software platform GISCAME was employed to bridge the gap between local land management decisions and regional planning by linking growth and yield models with an integrative mesoscale modeling and assessment approach. The model region is located in Saxony, Germany. Five scenarios were simulated, which aimed at testing different alternatives for adapted land use in the context of climate change and increasing biomass demand. The results showed, for example, that forest conversion towards climate-change-adapted forest types had positive effects on ecological integrity and landscape aesthetics. In contrast, negative impacts on landscape aesthetics must be expected if agricultural sites were converted into short rotation coppices. Uncertainties with stem from assumptions regarding growth and yield models were discussed. Future developmental steps which consider, for example, accessibility of the resources were identified.

  14. Exploring the Stressors of New Librarians

    Science.gov (United States)

    Larrivee, Anne

    2014-01-01

    This article describes the different stressors and anxieties facing new librarians. It also addresses the various ways that new librarians can cope with location, emotional, and work-related stressors. The article is broken into four different categories of stress; some stressors have been more explored than others. The research is based on an…

  15. Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

    International Nuclear Information System (INIS)

    Rozema, Jelte; Notten, Martje J.M.; Aerts, Rien; Gestel, Cornelis A.M. van; Hobbelen, Peter H.F.; Hamers, Timo H.M.

    2008-01-01

    This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded

  16. Job stressors, personality and burnout in primary school teachers.

    Science.gov (United States)

    Kokkinos, Constantinos M

    2007-03-01

    Teaching is considered a highly stressful occupation. Burnout is a negative affective response occurring as a result of chronic work stress. While the early theories of burnout focused exclusively on work-related stressors, recent research adopts a more integrative approach where both environmental and individual factors are studied. Nevertheless, such studies are scarce with teacher samples. The present cross-sectional study sought to investigate the association between burnout, personality characteristics and job stressors in primary school teachers from Cyprus. The study also investigates the relative contribution of these variables on the three facets of burnout - emotional exhaustion, depersonalization and reduced personal accomplishment. A representative sample of 447 primary school teachers participated in the study. Teachers completed measures of burnout, personality and job stressors along with demographic and professional data. Surveys were delivered by courier to schools, and were distributed at faculty meetings. Results showed that both personality and work-related stressors were associated with burnout dimensions. Neuroticism was a common predictor of all dimensions of burnout although in personal accomplishment had a different direction. Managing student misbehaviour and time constraints were found to systematically predict dimensions of burnout. Teachers' individual characteristics as well as job related stressors should be taken into consideration when studying the burnout phenomenon. The fact that each dimension of the syndrome is predicted by different variables should not remain unnoticed especially when designing and implementing intervention programmes to reduce burnout in teachers.

  17. Effects of two stressors on amphibian larval development.

    Science.gov (United States)

    Stark, Karolina; Scott, David E; Tsyusko, Olga; Coughlin, Daniel P; Hinton, Thomas G

    2012-05-01

    In parallel with a renewed interest in nuclear power and its possible environmental impacts, a new environmental radiation protection system calls for environmental indicators of radiological stress. However, because environmental stressors seldom occur alone, this study investigated the combined effects of an ecological stressor (larval density) and an anthropogenic stressor (ionizing radiation) on amphibians. Scaphiopus holbrookii tadpoles reared at different larval densities were exposed to four low irradiation dose rates (0.13, 2.4, 21, and 222 mGy d(-1)) from (137)Cs during the sensitive period prior to and throughout metamorphosis. Body size at metamorphosis and development rate served as fitness correlates related to population dynamics. Results showed that increased larval density decreased body size but did not affect development rate. Low dose rate radiation had no impact on either endpoint. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Stressors, resources, and distress among homeless persons: a longitudinal analysis.

    Science.gov (United States)

    Wong, Y L; Piliavin, I

    2001-04-01

    Relations among stressors, resources, and psychological distress were examined using two waves of data obtained from a probability sample of homeless persons (N = 430) residing in a large, demographically diverse county in North California. The focus of research was to examine whether and how social resources and housing resources directly affect distress and mediate the impact of stress factors on depressive symptoms. Path analysis results revealed that levels of psychological distress were responsive to change in objective housing circumstances, with the attainment of domicile status being associated with fewer distress symptoms. Our findings, however, indicated only modest effects of social resources on psychological distress through direct effects and mediating effects of life stressors on distress. Overall, the study suggests that the relationships among stressors, resources, and distress for homeless persons may be understood within the same analytical framework for the general population.

  19. Same pattern, different mechanism: Locking onto the role of key species in seafloor ecosystem process.

    Science.gov (United States)

    Woodin, Sarah Ann; Volkenborn, Nils; Pilditch, Conrad A; Lohrer, Andrew M; Wethey, David S; Hewitt, Judi E; Thrush, Simon F

    2016-05-27

    Seafloor biodiversity is a key mediator of ecosystem functioning, but its role is often excluded from global budgets or simplified to black boxes in models. New techniques allow quantification of the behavior of animals living below the sediment surface and assessment of the ecosystem consequences of complex interactions, yielding a better understanding of the role of seafloor animals in affecting key processes like primary productivity. Combining predictions based on natural history, behavior of key benthic species and environmental context allow assessment of differences in functioning and process, even when the measured ecosystem property in different systems is similar. Data from three sedimentary systems in New Zealand illustrate this. Analysis of the behaviors of the infaunal ecosystem engineers in each system revealed three very different mechanisms driving ecosystem function: density and excretion, sediment turnover and surface rugosity, and hydraulic activities and porewater bioadvection. Integrative metrics of ecosystem function in some cases differentiate among the systems (gross primary production) and in others do not (photosynthetic efficiency). Analyses based on behaviors and activities revealed important ecosystem functional differences and can dramatically improve our ability to model the impact of stressors on ecosystem and global processes.

  20. Stressors in elite sport: a coach perspective.

    Science.gov (United States)

    Thelwell, Richard C; Weston, Neil J V; Greenlees, Iain A; Hutchings, Nicholas V

    2008-07-01

    We examined the varying performance and organizational stressors experienced by coaches who operate with elite athletes. Following interviews with eleven coaches, content analysis of the data revealed coaches to experience comparable numbers of performance and organizational stressors. Performance stressors were divided between their own performance and that of their athletes, while organizational stressors included environmental, leadership, personal, and team factors. The findings provide evidence that coaches experience a variety of stressors that adds weight to the argument that they should be labelled as "performers" in their own right. A variety of future research topics and applied issues are also discussed.

  1. Examination of ecosystems affected by the Chernobyl reactor accident and assessment of resulting radiation exposure of the population

    International Nuclear Information System (INIS)

    Fielitz, U.

    2001-01-01

    Since 1988, within the scope of several research projects, in 7,000 samples of soil, plants, mushrooms and game from forest ecosystems, the 137 Cs activity concentration was measured, in order to investigate the dynamics of the nuclide. The investigation sites are a spruce mountain forest near the village Bodenmais (Bavaria) and an oak forest close to Fuhrberg (Lower Saxony). In both forests, unfavourable location conditions cause a relativ high transfer of 137 Cs into plants and game. Typifying for the 3 forest sites was the high intra- and interspecies variablilty of the 137 Cs activity concentration. Even 14 years after the Chernobyl-fallout at the 3 investigation sites, the average 137 Cs inventory, contained in the top 10 cm of soil was 56% and 93% in the top 20 cm. From 1987 till 1994, in the leaves of the investigated plant species the 137 Cs activity concentration decreased significant, during the following years there was little change. The effective half life of 137 Cs varies between -3 years for raspberry and -24 years for the fern Pteridium aquillinum, whereas most of the plant species show half lifes of about -5 years. In 2000, as usual mushrooms from the Bodenmais investigation site showed the highest 137 Cs contaminations. The aggregated transfer factors (T agg ) for soil → plant and soil → flesh varied with several orders of magnitude. T agg values for Soil → autotroph plant species reached from 0,0001 m 2 .kg -1 to 0,41 m 2 .kg -1 . While at the permanent study plots in Bodenmais and Fuhrberg the T agg values were of comparable quantity, at Goettingen, they were lower than two orders of magnitude. For example T agg for Cs-137 in wild boar from Bodenmais was 392 times higher than for wild boar from Goettingen. From 1987 till 2000, the 137 Cs activity in roe-deer from Bodenmais varied according to the seasons, with highest values in autumn, and lowest values in spring. In consequence of the decrease of the 137 Cs activity concentration in

  2. Nurses′ workplace stressors and coping strategies

    Directory of Open Access Journals (Sweden)

    Vickie A Lambert

    2008-01-01

    Full Text Available Prior research has suggested that nurses, regardless of workplace or culture, are confronted with a variety of stressors. As the worldwide nursing shortage increases, the aged population becomes larger, there is an increase in the incidence of chronic illnesses and technology continues to advance, nurses continually will be faced with numerous workplace stressors. Thus, nurses, especially palliative care nurses, need to learn how to identify their workplace stressors and to cope effectively with these stressors to attain and maintain both their physical and mental health. This article describes workplace stressors and coping strategies, compares and contrasts cross-cultural literature on nurses′ workplace stressors and coping strategies, and delineates a variety of stress management activities that could prove helpful for contending with stressors in the workplace.

  3. Timing of stressors alters interactive effects on a coastal foundation species.

    Science.gov (United States)

    Bible, Jillian M; Cheng, Brian S; Chang, Andrew L; Ferner, Matthew C; Wasson, Kerstin; Zabin, Chela J; Latta, Marilyn; Sanford, Eric; Deck, Anna; Grosholz, Edwin D

    2017-09-01

    The effects of climate-driven stressors on organismal performance and ecosystem functioning have been investigated across many systems; however, manipulative experiments generally apply stressors as constant and simultaneous treatments, rather than accurately reflecting temporal patterns in the natural environment. Here, we assessed the effects of temporal patterns of high aerial temperature and low salinity on survival of Olympia oysters (Ostrea lurida), a foundation species of conservation and restoration concern. As single stressors, low salinity (5 and 10 psu) and the highest air temperature (40°C) resulted in oyster mortality of 55.8, 11.3, and 23.5%, respectively. When applied on the same day, low salinity and high air temperature had synergistic negative effects that increased oyster mortality. This was true even for stressor levels that were relatively mild when applied alone (10 psu and 35°C). However, recovery times of two or four weeks between stressors eliminated the synergistic effects. Given that most natural systems threatened by climate change are subject to multiple stressors that vary in the timing of their occurrence, our results suggest that it is important to examine temporal variation of stressors in order to more accurately understand the possible biological responses to global change. © 2017 by the Ecological Society of America.

  4. Examination of ecosystems affected by the Chernobyl reactor accident and assessment of resulting radiation exposure of the population

    International Nuclear Information System (INIS)

    Fielitz, U.

    1999-01-01

    This paper deals with investigations about the behaviour of radiocaesium, carried out in two selected forest ecosystems. In 1997 and 1998 samples from soil, plants, trees and roe deer from forest areas, located near Bodenmais (Bavaria) and Fuhrberg (Lower Saxony) were measured on the 137 Cs activity. In this areas intensive studies about the behaviour of radiocaesium were already carried out from 1987 until 1994, so that long term data are available. Investigations on vertical distribution of 137 Cs in soil were leaded through on permanent 100 x 100 m study plots. Even 11 years after the Chernobyl-fallout, the activity is highest in humic horizonts, only vestiges were found deeper than 20 cm in soil profile. The majority of total activity is still present in the upper 10 cm of soil. At the permant study plot B1 in Bodenmais in 1997 there were found about 78% of the 137 Cs activity concentration (100%=100830 Bq x m -2 ) in this layer, of what 27% were located in the 4 cm thick humic layer. Comparisons of the vertical distribution in 1998, 1992 and 1997 show, that the velocity of radiocesium migration takes down with time. From 1987 until 1998 the 137 Cs activity in leaves of different plant species decreased significant. The effective half life of 137 Cs varies between 5 years for raspberry (Rubus idaeus) and 33 years for fern (Pteridium aquillinum), whereby most of the plant species show half lifes of about 10 years. The 137 Cs activity-decline slowed down from 1994 until 1998. There were considerable differences in 137 Cs activity between various plant species. 1998 for example, the concentration of 137 Cs in samples, taken at the same time from the permanent study plot B1, ranged from 380 Bq x kg -1 (dry weight) in raspberry to 16800 Bq x kg -1 in fern (Dryopteris carthusiana). In muscle flesh of roe-deer of Bodenmais from 1987 until 1998 the 137 Cs activity varied according to the seasons, the highest values were found in autumn, the lowest values in spring. In

  5. Interactive effects of climate change and biodiversity loss on ecosystem functioning.

    Science.gov (United States)

    Pires, Aliny P F; Srivastava, Diane S; Marino, Nicholas A C; MacDonald, A Andrew M; Figueiredo-Barros, Marcos Paulo; Farjalla, Vinicius F

    2018-05-01

    Climate change and biodiversity loss are expected to simultaneously affect ecosystems, however research on how each driver mediates the effect of the other has been limited in scope. The multiple stressor framework emphasizes non-additive effects, but biodiversity may also buffer the effects of climate change, and climate change may alter which mechanisms underlie biodiversity-function relationships. Here, we performed an experiment using tank bromeliad ecosystems to test the various ways that rainfall changes and litter diversity may jointly determine ecological processes. Litter diversity and rainfall changes interactively affected multiple functions, but how depends on the process measured. High litter diversity buffered the effects of altered rainfall on detritivore communities, evidence of insurance against impacts of climate change. Altered rainfall affected the mechanisms by which litter diversity influenced decomposition, reducing the importance of complementary attributes of species (complementarity effects), and resulting in an increasing dependence on the maintenance of specific species (dominance effects). Finally, altered rainfall conditions prevented litter diversity from fueling methanogenesis, because such changes in rainfall reduced microbial activity by 58%. Together, these results demonstrate that the effects of climate change and biodiversity loss on ecosystems cannot be understood in isolation and interactions between these stressors can be multifaceted. © 2018 by the Ecological Society of America.

  6. Growing Pains: The Impact of Disaster-Related and Daily Stressors on the Psychological and Psychosocial Functioning of Youth in Sri Lanka

    Science.gov (United States)

    Fernando, Gaithri A.; Miller, Kenneth E.; Berger, Dale E.

    2010-01-01

    Daily stressors may mediate the relation between exposure to disaster-related stressors and psychological and psychosocial distress among youth in disaster-affected countries. A sample of 427 Sri Lankan Sinhalese, Tamil, and Muslim youth (mean age = 14.5) completed a survey with measures of exposure to disaster-related stressors and daily…

  7. Species of conservation concern and environmental stressors: Local regional and global effects [Chapter 6

    Science.gov (United States)

    Steven M. Ostoja; Mathew L. Brooks; Jeanne C. Chambers; Burton K. Pendleton

    2013-01-01

    Species conservation has traditionally been based on individual species within the context of their requisite habitat, which is generally defined as the communities and ecosystems deemed necessary for their persistence. Conservation decisions are hampered by the fact that environmental stressors that potentially threaten the persistence of species can operate at...

  8. Top-down control as important as nutrient enrichment for eutrophication effects in North Atlantic coastal ecosystems

    NARCIS (Netherlands)

    Ostman, Orjan; Eklof, Johan; Eriksson, Britas Klemens; Olsson, Jens; Moksnes, Per-Olav; Bergstrom, Ulf

    Seagrass and seaweed habitats constitute hotspots for diversity and ecosystem services in coastal ecosystems. These habitats are subject to anthropogenic pressures, of which eutrophication is one major stressor. Eutrophication favours fast-growing ephemeral algae over perennial macroalgae and

  9. Plains zebra (Equus quagga) adrenocortical activity increases during times of large aggregations in the Serengeti ecosystem.

    Science.gov (United States)

    Seeber, P A; Franz, M; Dehnhard, M; Ganswindt, A; Greenwood, A D; East, M L

    2018-04-20

    Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11β-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, David [North Carolina State Univ., Raleigh, NC (United States); Osburn, Christopher [North Carolina State Univ., Raleigh, NC (United States); Oberbauer, Steven [Florida Intl Univ., Miami, FL (United States); Oviedo Vargas, Diana [North Carolina State Univ., Raleigh, NC (United States); Dierick, Diego [Florida Intl Univ., Miami, FL (United States)

    2017-03-27

    This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

  11. Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes

    Science.gov (United States)

    Mora, Camilo; Aburto-Oropeza, Octavio; Ayala Bocos, Arturo; Ayotte, Paula M.; Banks, Stuart; Bauman, Andrew G.; Beger, Maria; Bessudo, Sandra; Booth, David J.; Brokovich, Eran; Brooks, Andrew; Chabanet, Pascale; Cinner, Joshua E.; Cortés, Jorge; Cruz-Motta, Juan J.; Cupul Magaña, Amilcar; DeMartini, Edward E.; Edgar, Graham J.; Feary, David A.; Ferse, Sebastian C. A.; Friedlander, Alan M.; Gaston, Kevin J.; Gough, Charlotte; Graham, Nicholas A. J.; Green, Alison; Guzman, Hector; Hardt, Marah; Kulbicki, Michel; Letourneur, Yves; López Pérez, Andres; Loreau, Michel; Loya, Yossi; Martinez, Camilo; Mascareñas-Osorio, Ismael; Morove, Tau; Nadon, Marc-Olivier; Nakamura, Yohei; Paredes, Gustavo; Polunin, Nicholas V. C.; Pratchett, Morgan S.; Reyes Bonilla, Héctor; Rivera, Fernando; Sala, Enric; Sandin, Stuart A.; Soler, German; Stuart-Smith, Rick; Tessier, Emmanuel; Tittensor, Derek P.; Tupper, Mark; Usseglio, Paolo; Vigliola, Laurent; Wantiez, Laurent; Williams, Ivor; Wilson, Shaun K.; Zapata, Fernando A.

    2011-01-01

    Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas. PMID:21483714

  12. Timing matters: the interval between acute stressors within chronic mild stress modifies behavioral and physiologic stress responses in male rats.

    Science.gov (United States)

    Cavigelli, Sonia A; Bao, Alexander D; Bourne, Rebecca A; Caruso, Michael J; Caulfield, Jasmine I; Chen, Mary; Smyth, Joshua M

    2018-04-12

    Chronic mild stress can lead to negative health outcomes. Frequency, duration, and intensity of acute stressors can affect health-related processes. We tested whether the temporal pattern of daily acute stressors (clustered or dispersed across the day) affects depression-related physiology. We used a rodent model to keep stressor frequency, duration, and intensity constant, and experimentally manipulated the temporal pattern of acute stressors delivered during the active phase of the day. Adult male Sprague-Dawley rats were exposed to one of three chronic mild stress groups: Clustered: stressors that occurred within 1 hour of each other (n = 21), Dispersed: stressors that were spread out across the active phase (n = 21), and Control: no stressors presented (n = 21). Acute mild stressors included noise, strobe lights, novel cage, cage tilt, wet bedding, and water immersion. Depression-related outcomes included: sucrose preference, body weight, circulating glucocorticoid (corticosterone) concentration after a novel acute stressor and during basal morning and evening times, and endotoxin-induced circulating interleukin-6 concentrations. Compared to control rats, those in the Clustered group gained less weight, consumed less sucrose, had a blunted acute corticosterone response, and an accentuated acute interleukin-6 response. Rats in the Dispersed group had an attenuated corticosterone decline during the active period and after an acute stressor compared to the Control group. During a chronic mild stress experience, the temporal distribution of daily acute stressors affected health-related physiologic processes. Regular exposure to daily stressors in rapid succession may predict more depression-related symptoms, whereas exposure to stressors dispersed throughout the day may predict diminished glucocorticoid negative feedback.

  13. Avian wildlife as sentinels of ecosystem health.

    Science.gov (United States)

    Smits, Judit E G; Fernie, Kimberly J

    2013-05-01

    Birds have been widely used as sentinels of ecosystem health reflecting changes in habitat quality, increased incidence of disease, and exposure to and effects of chemical contaminants. Numerous studies addressing these issues focus on the breeding period, since hormonal, behavioural, reproductive, and developmental aspects of the health can be observed over a relatively short time-span. Many body systems within individuals are tightly integrated and interdependent, and can be affected by contaminant chemicals, disease, and habitat changes in complex ways. Animals higher in the food web will reflect cumulative effects of multiple stressors. Such features make birds ideal indicators for assessing environmental health in areas of environmental concern. Five case studies are presented, highlighting the use of different species which have provided insight into ecosystem sustainability, including (i) the consequences of anthropogenic disturbances of sagebrush habitat on the greater northern sage grouse Centrocercus urophasianus; (ii) the high prevalence of disease in very specific passerine species in the Canary Islands closely paralleling deterioration of formerly productive desert habitat and ensuing interspecific stressors; (iii) fractures, abnormal bone structure, and associated biochemical aberrations in nestling storks exposed to acidic tailings mud from a dyke rupture at an iron pyrite mine near Sevilla, Spain; (iv) newly presented data demonstrating biochemical changes in nestling peregrine falcons Falco peregrinus and associations with exposure to major chemical classes in the Great Lakes Basin of Canada; and (v) the variability in responses of tree swallows Tachycineta bicolor to contaminants, biological and meteorological challenges when breeding in the Athabasca oil sands. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Controls of Multiple Stressors on the Black Sea Fishery

    Directory of Open Access Journals (Sweden)

    Temel Oguz

    2017-04-01

    Full Text Available Black Sea is one of the most severely degraded and exploited large marine ecosystems in the world. For the last 50 years after the depletion of large predatory fish stocks, anchovy (with the partial contribution of sprat has been acting as the main top predator species and experienced a major stock collapse at the end of 1990s. After the collapse, eastern part of the southern Black Sea became the only region sustaining relatively high anchovy catch (400,000 tons whereas the total catch within the rest of the sea was reduced to nearly its one-third. The lack of recovery of different fish stocks under a slow ecosystem rehabilitation may be attributed, on the one hand, to inappropriate management measures and the lack of harmonized fishery policy among the riparian countries. On the other hand, impacts of multiple stressors (eutrophication, alien species invasions, natural climatic variations on the food web may contribute to resilience of the system toward its recovery. The overfishing/recovery problem therefore cannot be isolated from rehabilitation efforts devoted to the long-term chronic degradation of the food web structure, and alternative fishery-related management measures must be adopted as a part of a comprehensive ecosystem-based management strategy. The present study provides a data-driven ecosystem assessment, underlines the key environmental issues and threats, and points to the critical importance of holistic approach to resolve the fishery-ecosystem interactions. It also stresses the transboundary nature of the problem.

  15. The Correlation of Organizational Role Stressors with Stress Level of Icu Nurses

    OpenAIRE

    Nursalam, Nursalam; Efendi, Ferry; Puspawati, Ni Luh Putu Dewi

    2009-01-01

    Introduction : Work stress which is often experienced by ICU nurses may affects nurse’s performance, nurse’s health and wealth so that the factors which may affect work stress such as organizational role stressors must be noticed. This study was aimed to explain the correlation between organizational role stressors and work stress level in ICU Nurses. Method : This study used cross-sectional design  involved 13 respondents, taken by purposive sampling. The independent variable was organizatio...

  16. The Correlation of Organizational Role Stressors with Stress Level of ICU Nurses

    OpenAIRE

    Nursalam, Nursalam; Efendi, Ferry; Puspawati, Ni Luh Putu Dewi

    2017-01-01

    Introduction : Work stress which is often experienced by ICU nurses may affects nurse’s performance, nurse’s health and wealth so that the factors which may affect work stress such as organizational role stressors must be noticed. This study was aimed to explain the correlation between organizational role stressors and work stress level in ICU Nurses. Method : This study used cross-sectional design  involved 13 respondents, taken by purposive sampling. The independent variable was organizatio...

  17. Impact of multiple stressors on juvenile fish in estuaries of the northeast Pacific.

    Science.gov (United States)

    Toft, Jason D; Munsch, Stuart H; Cordell, Jeffery R; Siitari, Kiira; Hare, Van C; Holycross, Brett M; DeBruyckere, Lisa A; Greene, Correigh M; Hughes, Brent B

    2018-05-01

    A key step in identifying global change impacts on species and ecosystems is to quantify effects of multiple stressors. To date, the science of global change has been dominated by regional field studies, experimental manipulation, meta-analyses, conceptual models, reviews, and studies focusing on a single stressor or species over broad spatial and temporal scales. Here, we provide one of the first studies for coastal systems examining multiple stressor effects across broad scales, focused on the nursery function of 20 estuaries spanning 1,600 km of coastline, 25 years of monitoring, and seven fish and invertebrate species along the northeast Pacific coast. We hypothesized those species most estuarine dependent and negatively impacted by human activities would have lower presence and abundances in estuaries with greater anthropogenic land cover, pollution, and water flow stress. We found significant negative relationships between juveniles of two of seven species (Chinook salmon and English sole) and estuarine stressors. Chinook salmon were less likely to occur and were less abundant in estuaries with greater pollution stress. They were also less abundant in estuaries with greater flow stress, although this relationship was marginally insignificant. English sole were less abundant in estuaries with greater land cover stress. Together, we provide new empirical evidence that effects of stressors on two fish species culminate in detectable trends along the northeast Pacific coast, elevating the need for protection from pollution, land cover, and flow stressors to their habitats. Lack of response among the other five species could be related to differing resistance to specific stressors, type and precision of the stressor metrics, and limitations in catch data across estuaries and habitats. Acquiring improved measurements of impacts to species will guide future management actions, and help predict how estuarine nursery functions can be optimized given anthropogenic

  18. Response of the Eastern Mediterranean microbial ecosystem to dust and dust affected by acid processing in the atmosphere

    Directory of Open Access Journals (Sweden)

    Michael David Krom

    2016-08-01

    Full Text Available Acid processes in the atmosphere, particularly those caused by anthropogenic acid gases, increase the amount of bioavailable P in dust and hence are predicted to increase microbial biomass and primary productivity when supplied to oceanic surface waters. This is likely to be particularly important in the Eastern Mediterranean Sea (EMS, which is P limited during the winter bloom and N&P co-limited for phytoplankton in summer. However, it is not clear how the acid processes acting on Saharan dust will affect the microbial biomass and primary productivity in the EMS. Here, we carried out bioassay manipulations on EMS surface water on which Saharan dust was added as dust (Z, acid treated dust (ZA, dust plus excess N (ZN and acid treated dust with excess N (ZNA during springtime (May 2012 and measured bacterioplankton biomass, metabolic and other relevant chemical and biological parameters. We show that acid treatment of Saharan dust increased the amount of bioavailable P supplied by a factor of ~40 compared to non-acidified dust (18.4 nmoles P mg-1 dust vs. 0.45 nmoles P mg-1 dust, respectively. The increase in chlorophyll, primary and bacterial productivity for treatments Z and ZA were controlled by the amount of N added with the dust while those for treatments ZN and ZNA (in which excessive N was added were controlled by the amount of P added. These results confirm that the surface waters were N&P co-limited for phytoplankton during springtime. However, total chlorophyll and primary productivity in the acid treated dust additions (ZA and ZNA were less than predicted from that calculated from the amount of the potentially limiting nutrient added. This biological inhibition was interpreted as being due to labile trace metals being added with the acidified dust. A probable cause for this biological inhibition was the addition of dissolved Al, which forms potentially toxic Al nanoparticles when added to seawater. Thus, the effect of anthropogenic acid

  19. Ecosystem Services

    Science.gov (United States)

    Ecosystem goods and services are the many life-sustaining benefits we receive from nature and contribute to environmental and human health and well-being. Ecosystem-focused research will develop methods to measure ecosystem goods and services.

  20. Examination of the pattern of teachers' work stressors in relation to job satisfaction

    Directory of Open Access Journals (Sweden)

    Branko Slivar

    2008-11-01

    Full Text Available Stress is affecting teachers in their daily work and is related to low job satisfaction, low work motivation, low affiliation to organization etc. The study explored not only the relationship between teacher stress and job satisfaction but also the structure of patterns between various teacher's work stressors and particular elements of job satisfaction. In order to develop better understanding of the nature of the stressor experience, a study was undertaken to explore the stressor-job satisfaction relationship using sequential tree analysis. The study included 442 primary school teachers and 191 gymnasium school teachers. Results showed that different stressor patterns were associated with different levels of satisfaction and that there are differences in structure and in patterns of stressors among teachers from different types of schools.

  1. Resilience of Soil Microbial Communities to Metals and Additional Stressors: DNA-Based Approaches for Assessing “Stress-on-Stress” Responses

    Directory of Open Access Journals (Sweden)

    Hamed Azarbad

    2016-06-01

    Full Text Available Many microbial ecology studies have demonstrated profound changes in community composition caused by environmental pollution, as well as adaptation processes allowing survival of microbes in polluted ecosystems. Soil microbial communities in polluted areas with a long-term history of contamination have been shown to maintain their function by developing metal-tolerance mechanisms. In the present work, we review recent experiments, with specific emphasis on studies that have been conducted in polluted areas with a long-term history of contamination that also applied DNA-based approaches. We evaluate how the “costs” of adaptation to metals affect the responses of metal-tolerant communities to other stress factors (“stress-on-stress”. We discuss recent studies on the stability of microbial communities, in terms of resistance and resilience to additional stressors, focusing on metal pollution as the initial stress, and discuss possible factors influencing the functional and structural stability of microbial communities towards secondary stressors. There is increasing evidence that the history of environmental conditions and disturbance regimes play central roles in responses of microbial communities towards secondary stressors.

  2. Agreeableness, Extraversion, Stressor and Physiological Stress Response

    OpenAIRE

    Xiaoyuan Chu; Zhentao Ma; Yuan Li; Jing Han

    2015-01-01

    Based on the theoretical analysis, with first-hand data collection and using multiple regression models, this study explored the relationship between agreeableness, extraversion, stressor and stress response and figured out interactive effect of agreeableness, extraversion, and stressor on stress response. We draw on the following conclusions: (1) the interaction term of stressor (work) and agreeableness can negatively predict physiological stress response; (2) the interaction term of stresso...

  3. Reconceptualizing synergism and antagonism among multiple stressors

    OpenAIRE

    Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D

    2015-01-01

    The potential for complex synergistic or antagonistic interactions between multiple stressors presents one of the largest uncertainties when predicting ecological change but, despite common use of the terms in the scientific literature, a consensus on their operational definition is still lacking. The identification of synergism or antagonism is generally straightforward when stressors operate in the same direction, but if individual stressor effects oppose each other, the definition of syner...

  4. An Indicator for ecosystem externalities in fishing

    DEFF Research Database (Denmark)

    Ravn-Jonsen, Lars; Andersen, Ken Haste; Vestergaard, Niels

    Ecosystem externalities arise when one use of an ecosystem affects its other uses through the production functions of the ecosystem.We use simulations from a size-spectrum ecosystem model to investigate the ecosystem externality created by fishing of multiple species. The model is based upon...

  5. Management of Local Stressors Can Improve the Resilience of Marine Canopy Algae toGlobal Stressors

    NARCIS (Netherlands)

    Strain, E.M.A.; van Belzen, J.; van Dalen, J.; Bouma, T.J.; Airoldi, L.

    2015-01-01

    Coastal systems are increasingly threatened by multiple local anthropogenic and global climatic stressors. With the difficulties in remediating global stressors, management requires alternative approaches that focus on local scales. We used manipulative experiments to test whether reducing local

  6. Interpersonal workplace stressors and well-being: a multi-wave study of employees with and without arthritis.

    Science.gov (United States)

    Potter, Phillip T; Smith, Bruce W; Strobel, Kari R; Zautra, Alex J

    2002-08-01

    The within-person influence of interpersonal stressors on affective well-being and physical well-being was investigated for 109 women with and without arthritis. Participants were interviewed on a weekly basis for 12 consecutive weeks, and the prospective data were analyzed by using hierarchical linear modeling. Overall, interpersonal workplace stressors independently predicted both well-being outcomes. Interpersonal stressors outside the workplace were related to negative affect but not to arthritis symptoms. Compared with healthy controls, arthritis patients' ratings of negative affect were equally reactive to workplace stressors. Neuroticism did not moderate stressor reactivity for either dependent variable but did predict mean levels of negative affect. The data support the hypothesis that the psychosocial environment of the workplace contributes unique effects on well-being.

  7. Secondary stressors and extreme events and disasters: a systematic review of primary research from 2010-2011

    Science.gov (United States)

    Lock, Sarah; Rubin, G. James; Murray, Virginia; Rogers, M. Brooke; Amlôt, Richard; Williams, Richard

    2012-01-01

    Introduction Extreme events and disasters, such as earthquakes and floods, cause distress and are associated with some people developing mental disorders. Primary stressors inherent in many disasters can include injuries sustained or watching someone die. The literature recognises the distress which primary stressors cause and their association with mental disorders. Secondary stressors such as a lack of financial assistance, the gruelling process of submitting an insurance claim, parents’ worries about their children, and continued lack of infrastructure can manifest their effects shortly after a disaster and persist for extended periods of time. Secondary stressors, and their roles in affecting people’s longer-term mental health, should not be overlooked. We draw attention in this review to the nature of secondary stressors that are commonly identified in the literature, assess how they are measured, and develop a typology of these stressors that often affect people after extreme events. Methods We searched for relevant papers from 2010 and 2011 using MEDLINE®, Embase and PsycINFO®. We selected primary research papers that evaluated the associations between secondary stressors and distress or mental disorders following extreme events, and were published in English. We extracted information on which secondary stressors were assessed, and used thematic analysis to group the secondary stressors into a typology. Results Thirty-two relevant articles published in 2010 and 2011 were identified. Many secondary stressors were poorly defined and difficult to differentiate from primary stressors or other life events. We identified 11 categories of secondary stressors, though some extend over more than one category. The categories include: economic stressors such as problems with compensation, recovery of and rebuilding homes; loss of physical possessions and resources; health-related stressors; stress relating to education and schooling; stress arising from media

  8. Interactive effects of an insecticide and a fungicide on different organism groups and ecosystem functioning in a stream detrital food web.

    Science.gov (United States)

    Dawoud, Mohab; Bundschuh, Mirco; Goedkoop, Willem; McKie, Brendan G

    2017-05-01

    Freshwater ecosystems are often affected by cocktails of multiple pesticides targeting different organism groups. Prediction and evaluation of the ecosystem-level effects of these mixtures is complicated by the potential not only for interactions among the pesticides themselves, but also for the pesticides to alter biotic interactions across trophic levels. In a stream microcosm experiment, we investigated the effects of two pesticides targeting two organism groups (the insecticide lindane and fungicide azoxystrobin) on the functioning of a model stream detrital food web consisting of a detritivore (Ispoda: Asellus aquaticus) and microbes (an assemblage of fungal hyphomycetes) consuming leaf litter. We assessed how these pesticides interacted with the presence and absence of the detritivore to affect three indicators of ecosystem functioning - leaf decomposition, fungal biomass, fungal sporulation - as well as detritivore mortality. Leaf decomposition rates were more strongly impacted by the fungicide than the insecticide, reflecting especially negative effects on leaf processing by detritivores. This result most like reflects reduced fungal biomass and increased detritivore mortality under the fungicide treatment. Fungal sporulation was elevated by exposure to both the insecticide and fungicide, possibly representing a stress-induced increase in investment in propagule dispersal. Stressor interactions were apparent in the impacts of the combined pesticide treatment on fungal sporulation and detritivore mortality, which were reduced and elevated relative to the single stressor treatments, respectively. These results demonstrate the potential of trophic and multiple stressor interactions to modulate the ecosystem-level impacts of chemicals, highlighting important challenges in predicting, understanding and evaluating the impacts of multiple chemical stressors on more complex food webs in situ. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Can "good" stressors spark "bad" behaviors? The mediating role of emotions in links of challenge and hindrance stressors with citizenship and counterproductive behaviors.

    Science.gov (United States)

    Rodell, Jessica B; Judge, Timothy A

    2009-11-01

    The authors combined affective events theory (H. M. Weiss & Cropanzano, 1996) and the transactional stress model (R. S. Lazarus & Folkman, 1984) to build and test a model specifying the dynamic, emotion-based relationships among challenge and hindrance stressors and citizenship and counterproductive behaviors. The study employed an experience sampling methodology. Results showed that challenge stressors had offsetting indirect links with citizenship behaviors through attentiveness and anxiety and a positive indirect effect on counterproductive behaviors through anxiety. Hindrance stressors had a negative indirect effect on citizenship behaviors through anxiety and a positive indirect effect on counterproductive behaviors through anxiety and anger. Finally, multilevel moderating effects showed that the relationship between hindrance stressors and anger varied according to employees' levels of neuroticism.

  10. Intra-family stressors among adult siblings sharing caregiving for parents.

    Science.gov (United States)

    Ngangana, Pamela C; Davis, Bertha L; Burns, Dorothy P; McGee, Zina T; Montgomery, Arlene J

    2016-12-01

    The aim of this study was to describe a Neuman Systems Model-guided study of perceptions of family stressors experienced by adult siblings who share caregiving for their parents and the influence of these stressors on adult siblings' relationships. The task of providing informal care for disabled parents is often shared by adult siblings. Family stressors experienced as part of caregiving may affect the sibling relationship. A mixed-method study design was used. Data were collected during 2013-2014 from 84 adult sibling caregivers. Seventy-two caregivers provided quantitative data for the Lifespan Sibling Relationship Scale and the Zarit Burden Scale and 79 provided qualitative data for the open-ended question. Adult siblings experienced mild-to-moderate levels of burden from family stressors when they share parental caregiving. The amount of burden from intra-family stressors was negatively related to the adult sibling relationship. Beneficial and noxious stressors were evident in the participants' responses to an open-ended question. The health of the parents affected the lives of adult siblings in both negative and positive ways. Although the majority of the adult siblings expressed a willingness to care for their parent(s) in an attempt to reciprocate the care, they had received from them, challenges emerged from dealing with family stressors. © 2016 John Wiley & Sons Ltd.

  11. Stressors relating to patient psychological health following stoma surgery: an integrated literature review.

    Science.gov (United States)

    Ang, Seng Giap Marcus; Chen, Hui-Chen; Siah, Rosalind Jiat Chiew; He, Hong-Gu; Klainin-Yobas, Piyanee

    2013-11-01

    To summarize empirical evidence relating to stressors that may affect patients' psychosocial health following colostomy or ileostomy surgery during hospitalization and after discharge. An extensive search was performed on the CINAHL®, Cochrane Library, PubMed, PsycINFO, Scopus, Science Direct, and Web of Science electronic databases. Eight articles were included with three qualitative and five quantitative research designs. Most studies were conducted in Western nations with one other in Taiwan. Following colostomy or ileostomy surgery, common stressors reported by patients during hospitalization included stoma formation, diagnosis of cancer, and preparation for self-care. After discharge, stressors that patients experienced encompassed adapting to body changes, altered sexuality, and impact on social life and activities. This review suggests that patients with stomas experience various stressors during hospitalization and after discharge. Additional research is needed for better understanding of patient postoperative experiences to facilitate the provision of appropriate nursing interventions to the stressors. To help patients deal with stressors following stoma surgery, nurses may provide pre- and postoperative education regarding the treatment and recovery process and encourage patient self-care. Following discharge, nurses may provide long-term ongoing counseling and support, build social networks among patients with stomas, and implement home visit programs. Stoma surgery negatively affects patients' physical, psychological, social, and sexual health. Postoperative education programs in clinical settings mostly focus on physical health and underemphasize psychological issues. More pre- and postoperative education programs are needed to help patients cope with stoma stressors.

  12. Multiple-stressor impacts on Spartina alterniflora and Distichlis spicata

    Science.gov (United States)

    Salt marshes are subject to an array of environmental changes that have the potential to alter community structure and function. Manipulative experiments often study environmental changes in isolation, although changes may interactively affect plant and ecosystem response. We rep...

  13. Teaching Practice generated stressors and coping mechanisms ...

    African Journals Online (AJOL)

    Teaching Practice generated stressors and coping mechanisms among student teachers in Zimbabwe. ... South African Journal of Education ... We sought to establish stressors and coping mechanisms for student teachers on Teaching Practice from a Christian-related university and a government-owned teachers' college ...

  14. Stressor sensor and stress management system

    NARCIS (Netherlands)

    2012-01-01

    A stressor detection system (100) comprises sensor means (101) arranged for being attached to a person for obtaining a time-varying signal representing a physical quantity relating to an environment of the person, and processing means (102) for deriving a stressor value from the obtained signal

  15. Radionuclides in an arctic terrestrial ecosystem affected by atmospheric release from the Kraton-3 accidental underground nuclear explosion. 2001-2002

    International Nuclear Information System (INIS)

    Ramzaev, V.; Golikov, V.; Mishine, A.; Kaduka, M.; Burtcev, I.; Gedeonov, A.; Bulatenkov, Y.U.; Strand, P.; Brown, J.

    2004-01-01

    Current distributions of artificial radionuclides (ARN) were studied in the main compartments of a larch-tree forest lethally affected by a radioactive release from the Kraton-3 peaceful underground nuclear explosion (65.9 deg N, 112.3 deg E; Yakutia, Russia; 1978). Samples of soil, fungi, lichens, mosses, grasses, shrubs and trees were obtained at points belonging to four zones categorised by the severity of the ecosystem damage. Sampling was supplemented by dose rate measurements in air and mapping. The area of forest characterised by 100% lethality to adult larches (Larix gmelinii) and with partial, visually-detectable damage of other more radio-resistance species (e.g. lichens, mosses) covers a territory of approximately 1.2 km 2 . Elevated levels of long-lived ARN were found at all sampling sites. Maximum registered levels of the ground contamination with radionuclides of Cs, Sr and Pu were three orders of magnitude higher than those expected from global fallout. The ratios of 137 Cs to some other significant radionuclides in the ground contamination were as follows [mean (range)]: 90 Sr - 0.57(0.02-0.93); 239,240 Pu 44(25-72); 60 Co 470(220-760). Twenty-three years after a discrete contamination event, 90-95% of the total deposited radiocesium and plutonium has still remained in the lichen-moss on-ground cover and in the top 5 cm organic soil layer. At the same time, vertical and horizontal migrations of 90 Sr in soil were more pronounced. Strong surface contamination with 137 Cs, 90 Sr and plutonium was detected at the twigs and bark of the dead larches. The young larches that grew at the contaminated area following the initial destruction of the forest demonstrated a substantial ability to accumulate 137 Cs, 90 Sr and plutonium via roots, while the bushes selectively accumulated mainly radiostrontium. In contrast, some fungi concentrated mostly radiocesium. The levels of gamma dose rate in air and the environmental contamination with 137 Cs were found to

  16. Daily Stressor Reactivity during Adolescence: The Buffering Role of Parental Warmth

    Science.gov (United States)

    Lippold, Melissa; Davis, Kelly D.; McHale, Susan M.; Buxton, Orfeu; Almeida, David M.

    2016-01-01

    Objective This study examined youth stressor reactivity in the form of links between daily stressors and adolescents’ negative affect, physical health symptoms, and cortisol patterns. We also tested whether youth gender and parental warmth moderated these linkages. Method Participants were the children of employees in the Information Technology division of a large company (N = 132, mean age = 13.39 years, 55% female). Youth completed daily diary telephone interviews on 8 consecutive evenings and provided saliva samples at 4 time points over 4 days to assess daily stressors and youth physiological and affective functioning. Parental warmth was assessed during in-home interviews. Multi-level modeling was used to account for interdependencies in the data. Results Youth who experienced more daily stressors, on average, reported more negative affect and physical health symptoms, on average. Further, on days youth reported more stressors than usual (compared to their own across-day average), they also exhibited more physical health symptoms, reduced evening cortisol decline (e.g., flatter slopes), higher bedtime cortisol, and more negative affect. Girls had stronger within-person linkages between daily stressors and daily negative affect than boys. Parental warmth moderated these within-person linkages: Youth who experienced more parental warmth had lower negative affect and steeper cortisol decline than usual on less stressful days. Yet, youth who experienced less parental warmth had higher negative affect and their cortisol levels declined less, even on days with lower-than-usual stress. Conclusions Daily stressors are associated with youth's affective and physiological functioning, but parental warmth can support youth's stress recovery. PMID:27175577

  17. An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate.

    Science.gov (United States)

    Weijerman, Mariska; Fulton, Elizabeth A; Kaplan, Isaac C; Gorton, Rebecca; Leemans, Rik; Mooij, Wolf M; Brainard, Russell E

    2015-01-01

    Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers

  18. An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate.

    Directory of Open Access Journals (Sweden)

    Mariska Weijerman

    Full Text Available Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1 ratio of calcifying to non-calcifying benthic groups, 2 trophic level of the community, 3 biomass of apex predators, 4 biomass of herbivorous fishes, 5 total biomass of living groups and 6 the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations, climate change impacts have a slight positive interaction with

  19. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    Directory of Open Access Journals (Sweden)

    Peter O Alele

    Full Text Available Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE. Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted

  20. Wartime stressors and health outcomes: women in the Persian Gulf War.

    Science.gov (United States)

    Bell, E A; Roth, M A; Weed, G

    1998-08-01

    This descriptive correlational study of war time stressors and stress responses of women from the Persian Gulf War examined numerous stressors both physical and psychological. The psychological stressors more directly impacted postwar physical and psychological symptoms than did physical stressors. These findings add to our understanding of women's reactions to wartime stress and the types of stressors affecting women. The study provides more data to support the contention that sexual harassment is widely prevalent in the military. The study did not find data to support concerns about maternal guilt on leaving children, nor any significant evidence of stress symptomology from this situation. The results of this study confirmed the call by Wolfe, Brown, Furey, and Levin (1993) for more precise evaluation of wartime stressors in view of the changing gender composition of military forces and the subsequent increase of women in combat roles. Clinicians should be alerted to recognize gender-specific experiences. Education of military women about stressors and coping mechanisms should be broadened to address the development issue of intimacy versus isolation. Nurses, both military and civilian, must understand the effect of isolation and discrimination on women both in combat and in other high stress situations. The need for continued study of the problem of sexual harassment is confirmed. Understanding the scope of the problem and the health care outcomes strengthens the role of prevention and intervention for nurses and their clients.

  1. Workplace Stressors and Coping Strategies Among Public Hospital Nurses in Medan, Indonesia

    Directory of Open Access Journals (Sweden)

    Achmad Fathi

    2012-08-01

    Full Text Available Background: Nursing is considered as a stressful job when compared with other jobs. Prolonged stress without effective coping strategies affects not only nurses’ occupational life but also their nursing competencies. Medan is the biggest city in Sumatera Island of Indonesia. Two tertiary public hospital nurses in this city hold the responsibility in providing excellent care to their patients. Objective: To investigate the relationships between the nurse’s workplace stressors and the coping strategies used. Method: The descriptive correlational study was conducted to examine the relationships between workplace stressors and the coping strategies used in nurses of two public hospitals in Medan. The sample size of 126 nurses was drawn from selected in-patient units. Data were collected by using self-report questionnaires and focus group interview. The majority of subjects experienced low workplace stressors, where death/dying was the most commonly reported workplace stressor followed by workload. Religion was the most commonly used coping strategy. Result: Significant correlations were found between subscales of workplace stressors and coping strategies. Most of subjects used emotion-focused and dysfunctional coping strategies rather than problem-focused coping strategies. Conclusion: The nurse administrators in the hospitals need to advocate their in order to use problem-focused coping strategies more frequent than emotion-focused and dysfunctional coping strategies when dealing with workplace stressors. Keywords: workplace stressor, coping strategy, public hospital nurses

  2. Psychosocial stressors in inter-human relationships and health at each life stage: A review.

    Science.gov (United States)

    Kagamimori, Sadanobu; Nasermoaddeli, Ali; Wang, Hongbing

    2004-05-01

    Currently, psychosocial stressors' impacts on health are increasing. Among these stressors, this review focused on inter-human relationships. Since social supports could be protective against ill health, consequences contributing to psychosocial stressors are discussed here in relation to social supports for each stage of childhood, adulthood and elderly status.For childhood, parental divorce/isolation, and child abuse/neglect appeared to be determinants of healthy development at either the initial or later stages. According to prospective studies, such stressors, especially those occurring until around 3 years of age, were associated with later adverse life quality in adulthood. Therefore, nationwide preventive strategies were developed in each country to monitor protective social programs.For adulthood, job strain was focused on Karasek's job strain model, effort-reward imbalance, employment grade and working hours. These psychosocial stressors were shown to affect not only the physical health but also the mental health of working people. These days, since Karoshi and even suicide related to excessive workloads are taking a toll on workplace organization, stress-coping abilities such as a sense of coherence were introduced from the individual-social interaction aspect.For elderly status, retirement, caring for the elderly, and spouse bereavement were discussed as psychosocial stressors. Some evidence indicates that these stressors could be determiants of health. Finally, social supports have been demonstrated to promote health and protect the elderly against diseases and death.

  3. Ecological network analysis reveals the inter-connection between soil biodiversity and ecosystem function as affected by land use across Europe

    NARCIS (Netherlands)

    Creamer, R.C.; Hannula, S.E.; Leeuwen, van J.P.; Stone, D.; Rutgers, M.; Schmelz, R.M.; Ruiter, de P.C.; Bohse Hendriksen, N.; Bolger, T.; Bouffaud, M.L.; Buee, M.; Calvalho, F.; Costa, D.; Dirilgen, T.; Francisco, R.; Griffiths, B.S.; Griffiths, R.; Martin, F.; Martins da Silva, P.; Mendes, S.; Morais, P.V.; Pereira, C.; Philippot, L.; Plassart, P.; Redecker, D.; Römbke, J.; Sousa, J.P.; Wouterse, M.; Lemanceau, P.

    2016-01-01

    Soil organisms are considered drivers of soil ecosystem services (primary productivity, nutrient cycling, carbon cycling, water regulation) associated with sustainable agricultural production. Soil biodiversity was highlighted in the soil thematic strategy as a key component of soil quality. The

  4. Stressors, academic performance, and learned resourcefulness in baccalaureate nursing students.

    Science.gov (United States)

    Goff, Anne-Marie

    2011-01-01

    High stress levels in nursing students may affect memory, concentration, and problem-solving ability, and may lead to decreased learning, coping, academic performance, and retention. College students with higher levels of learned resourcefulness develop greater self-confidence, motivation, and academic persistence, and are less likely to become anxious, depressed, and frustrated, but no studies specifically involve nursing students. This explanatory correlational study used Gadzella's Student-life Stress Inventory (SSI) and Rosenbaum's Self Control Scale (SCS) to explore learned resourcefulness, stressors, and academic performance in 53 baccalaureate nursing students. High levels of personal and academic stressors were evident, but not significant predictors of academic performance (p = .90). Age was a significant predictor of academic performance (p = learned resourcefulness scores than females and Caucasians. Studies in larger, more diverse samples are necessary to validate these findings.

  5. Stressors and resources mediate the association of socioeconomic position with health behaviours

    Directory of Open Access Journals (Sweden)

    van Ameijden Erik JC

    2011-10-01

    Full Text Available Abstract Background Variability in health behaviours is an important cause of socioeconomic health disparities. Socioeconomic differences in health behaviours are poorly understood. Previous studies have examined whether (single stressors or psychosocial resources mediate the relationship between socioeconomic position and health or mortality. This study examined: 1 whether the presence of stressors and the absence of resources can be represented by a single underlying factor, and co-occur among those with lower education, 2 whether stressors and resources mediated the relation between education and health behaviours, and 3 addressed the question whether an aggregate measure of stressors and resources has an added effect over the use of individual measures. Methods Questionnaire data on sociodemographic variables, stressors, resources, and health behaviours were collected cross-sectionally among inhabitants (n = 3050 of a medium-sized Dutch city (Utrecht. Descriptive statistics and bootstrap analyses for multiple-mediator effects were used to examine the role of stressors and resources in mediating educational associations with health behaviours. Results Higher levels of stressors and lower levels of resources could be represented by a single underlying factor, and co-occurred among those with lower educational levels. Stressors and resources partially mediated the relationship between education and four health- behaviours (exercise, breakfast frequency, vegetable consumption and smoking. Financial stress and poor perceived health status were mediating stressors, and social support a strong mediating resource. An aggregate measure of the stressors and resources showed similar associations with health behaviours compared to the summed individual measures. Conclusions Lower educated groups are simultaneously affected by the presence of various stressors and absence of multiple resources, which partially explain socioeconomic differences in health

  6. Probing for Neuroadaptations to Unpredictable Stressors in Addiction: Translational Methods and Emerging Evidence

    Science.gov (United States)

    Kaye, Jesse T.; Bradford, Daniel E.; Magruder, Katherine P.; Curtin, John J.

    2017-01-01

    Stressors clearly contribute to addiction etiology and relapse in humans, but our understanding of specific mechanisms remains limited. Rodent models of addiction offer the power, flexibility, and precision necessary to delineate the causal role and specific mechanisms through which stressors influence alcohol and other drug use. This review describes a program of research using startle potentiation to unpredictable stressors that is well positioned to translate between animal models and clinical research with humans on stress neuroadaptations in addiction. This research rests on a solid foundation provided by three separate pillars of evidence from (a) rodent behavioral neuroscience on stress neuroadaptations in addiction, (b) rodent affective neuroscience on startle potentiation, and (c) human addiction and affective science with startle potentiation. Rodent stress neuroadaptation models implicate adaptations in corticotropin-releasing factor and norepinephrine circuits within the central extended amygdala following chronic alcohol and other drug use that mediate anxious behaviors and stress-induced reinstatement among drug-dependent rodents. Basic affective neuroscience indicates that these same neural mechanisms are involved in startle potentiation to unpredictable stressors in particular (vs. predictable stressors). We believe that synthesis of these evidence bases should focus us on the role of unpredictable stressors in addiction etiology and relapse. Startle potentiation in unpredictable stressor tasks is proposed to provide an attractive and flexible test bed to encourage tight translation and reverse translation between animal models and human clinical research on stress neuroadaptations. Experimental therapeutics approaches focused on unpredictable stressors hold high promise to identify, repurpose, or refine pharmacological and psychosocial interventions for addiction. PMID:28499100

  7. Psychological vulnerability to daily stressors in old age: Results of short-term longitudinal studies.

    Science.gov (United States)

    Schilling, Oliver Karl; Diehl, Manfred

    2015-08-01

    A growing numbers of intensive longitudinal studies examine the short-term variability of behavior in response to daily stressors. Collectively, these studies address the vulnerability for stress-related emotional burden as assessed in terms of the intraindividual association between daily stressors and negative affect (NA). This article provides a brief overview of the relevant research on so-called affective reactivity to daily stressors and focuses on findings on development of age-related stressor reactivity across the adult lifespan. Two theoretical propositions have been put forward. Firstly, it has been postulated that aging should be associated with increased affective reactivity, i.e. it has been assumed that the vulnerability in terms of physiological stress reactivity increases across the adult life span and, thus, a higher stress-induced emotional reactivity should result with increasing age. Secondly, it has been argued that due to the continued development of emotional self-regulation skills, there should be an age-related decrease in stress reactivity and, hence, an increased resilience. Findings on age differences in NA reactivity to daily stressors, however, have been inconsistent. A possible explanation for the inconsistent findings may lie in the fact that the postulated dynamics of increased vulnerability or resilience imply different time-related reactions to stressors. In particular, the activation and effectiveness of emotional self-regulation strategies increase with increasing time intervals from the stressors. This leads to the conclusion that with increasing age the resilience for longer periods of stress and accumulated stress should increase. Results from our own research support this hypothesis, where older adults reacted to multiple stressors in a more adaptive way than younger adults.

  8. Probing for Neuroadaptations to Unpredictable Stressors in Addiction: Translational Methods and Emerging Evidence.

    Science.gov (United States)

    Kaye, Jesse T; Bradford, Daniel E; Magruder, Katherine P; Curtin, John J

    2017-05-01

    Stressors clearly contribute to addiction etiology and relapse in humans, but our understanding of specific mechanisms remains limited. Rodent models of addiction offer the power, flexibility, and precision necessary to delineate the causal role and specific mechanisms through which stressors influence alcohol and other drug use. This review describes a program of research using startle potentiation to unpredictable stressors that is well positioned to translate between animal models and clinical research with humans on stress neuroadaptations in addiction. This research rests on a solid foundation provided by three separate pillars of evidence from (a) rodent behavioral neuroscience on stress neuroadaptations in addiction, (b) rodent affective neuroscience on startle potentiation, and (c) human addiction and affective science with startle potentiation. Rodent stress neuroadaptation models implicate adaptations in corticotropin-releasing factor and norepinephrine circuits within the central extended amygdala following chronic alcohol and other drug use that mediate anxious behaviors and stress-induced reinstatement among drug-dependent rodents. Basic affective neuroscience indicates that these same neural mechanisms are involved in startle potentiation to unpredictable stressors in particular (vs. predictable stressors). We believe that synthesis of these evidence bases should focus us on the role of unpredictable stressors in addiction etiology and relapse. Startle potentiation in unpredictable stressor tasks is proposed to provide an attractive and flexible test bed to encourage tight translation and reverse translation between animal models and human clinical research on stress neuroadaptations. Experimental therapeutics approaches focused on unpredictable stressors hold high promise to identify, repurpose, or refine pharmacological and psychosocial interventions for addiction.

  9. Alpine ecosystems

    Science.gov (United States)

    P.W. Rundel; C.I. Millar

    2016-01-01

    Alpine ecosystems are typically defined as those areas occurring above treeline, while recognizing that alpine ecosystems at a local scale may be found below this boundary for reasons including geology, geomorphology, and microclimate. The lower limit of the alpine ecosystems, the climatic treeline, varies with latitude across California, ranging from about 3500 m in...

  10. Ecosystem Jenga!

    Science.gov (United States)

    Umphlett, Natalie; Brosius, Tierney; Laungani, Ramesh; Rousseau, Joe; Leslie-Pelecky, Diandra L.

    2009-01-01

    To give students a tangible model of an ecosystem and have them experience what could happen if a component of that ecosystem were removed; the authors developed a hands-on, inquiry-based activity that visually demonstrates the concept of a delicately balanced ecosystem through a modification of the popular game Jenga. This activity can be…

  11. Human Stressors Are Driving Coastal Benthic Long-Lived Sessile Fan Mussel Pinna nobilis Population Structure More than Environmental Stressors.

    Directory of Open Access Journals (Sweden)

    Salud Deudero

    Full Text Available Coastal degradation and habitat disruption are severely compromising sessile marine species. The fan shell Pinna nobilis is an endemic, vulnerable species and the largest bivalve in the Mediterranean basin. In spite of species legal protection, fan shell populations are declining. Models analyzed the contributions of environmental (mean depth, wave height, maximum wave height, period of waves with high energy and mean direction of wave source versus human-derived stressors (anchoring, protection status, sewage effluents, fishing activity and diving as explanatory variables depicting Pinna nobilis populations at a mesoscale level. Human stressors were explaining most of the variability in density spatial distribution of fan shell, significantly disturbing benthic communities. Habitat protection affected P. nobilis structure and physical aggression by anchoring reveals a high impact on densities. Environmental variables instead played a secondary role, indicating that global change processes are not so relevant in coastal benthic communities as human-derived impacts.

  12. Human Stressors Are Driving Coastal Benthic Long-Lived Sessile Fan Mussel Pinna nobilis Population Structure More than Environmental Stressors.

    Science.gov (United States)

    Deudero, Salud; Vázquez-Luis, Maite; Álvarez, Elvira

    2015-01-01

    Coastal degradation and habitat disruption are severely compromising sessile marine species. The fan shell Pinna nobilis is an endemic, vulnerable species and the largest bivalve in the Mediterranean basin. In spite of species legal protection, fan shell populations are declining. Models analyzed the contributions of environmental (mean depth, wave height, maximum wave height, period of waves with high energy and mean direction of wave source) versus human-derived stressors (anchoring, protection status, sewage effluents, fishing activity and diving) as explanatory variables depicting Pinna nobilis populations at a mesoscale level. Human stressors were explaining most of the variability in density spatial distribution of fan shell, significantly disturbing benthic communities. Habitat protection affected P. nobilis structure and physical aggression by anchoring reveals a high impact on densities. Environmental variables instead played a secondary role, indicating that global change processes are not so relevant in coastal benthic communities as human-derived impacts.

  13. Integrating chemical and biological status assessment: Assembling lines of evidence for the evaluation of river ecosystem risk

    International Nuclear Information System (INIS)

    Munoz Gracia, Isabel; Sabater, Sergi

    2014-01-01

    This paper describes various approaches to evaluating ecological risk in rivers affected by multiple chemical stressors, with emphasis on biofilm and invertebrate community responses. Metrics should be considered as different lines of evidence that, when weighted, form an advanced weight of evidence approach to establishing the environmental risk on a basin scale. Combination of field surveys to obtain observational data of communities, in situ experiments, toxicological sediment tests and a good chemical description of the medium (water and sediment) helps give an integrative view of the chemical and biological state of a river ecosystem. The greater and more distinct the variables used, the greater is our ability to identify the effects of major stressors impairing communities. Weight of evidence is an integrative methodology for tackling the challenge of determining causal relations and applying this knowledge in the decision-making processes of river management.

  14. The impact of sport related stressors on immunity and illness risk in team-sport athletes.

    Science.gov (United States)

    Keaney, Lauren C; Kilding, Andrew E; Merien, Fabrice; Dulson, Deborah K

    2018-06-19

    Elite team-sport athletes are frequently exposed to stressors that have the potential to depress immunity and increase infection risk. Therefore, the purpose of this review is to describe how team-sport stressors impact upon immune responses, along with exploring whether alterations in these markers have the potential to predict upper respiratory tract illness symptoms. Narrative review. Salivary secretory immunoglobulin A (SIgA) and T-cell markers have been shown to predict infection risk in individual endurance athletes. Papers discussing the impact of team-sport stressors on SIgA and T-cells were discussed in the review, studies discussing other aspects of immunity were excluded. Journal articles were sourced from PubMed, Web of science and Scopus. Key search terms included team-sport athletes, stressors, immunity, T-cells, cytokines, SIgA and upper respiratory illness. Most team-sport stressors appear to increase risk for illness. An association between reduced SIgA and increased illness incidence has been demonstrated. Intensive training and competition periods have been shown to reduce SIgA, however, it is less clear how additional stressors including extreme environmental conditions, travel, psychological stress, sleep disturbance and poor nutrition affect immune responses. Monitoring SIgA may provide an assessment of a team-sport athletes risk status for developing upper respiratory tract symptoms, however there is currently not enough evidence to suggest SIgA alone can predict illness. Team-sport stressors challenge immunity and it is possible that the combination of stressors could have a compounding effect on immunodepression and infection risk. Given that illness can disrupt training and performance, further research is required to better elucidate how stressors individually and collectively influence immunity and illness. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. Criminal Justice Contact, Stressors, and Obesity-Related Health Problems Among Black Adults in the USA.

    Science.gov (United States)

    Archibald, Paul C; Parker, Lauren; Thorpe, Roland

    2018-04-01

    Criminal justice contact-defined as lifetime arrest, parole, or incarceration, seems to exacerbate chronic conditions, and those who are most likely to have had contact with the criminal justice system, such as Black adults, often already have pre-existing disproportionately high rates of stress and chronic conditions due to the social determinants of health that affect underrepresented minorities. Findings from this study suggest that there is a mechanism that links the stressors among Black adults manifested by such factors as family, financial, neighborhood, and personal problems with criminal justice contact to obesity-related health status. Using the National Survey of American Life (NSAL), modified Poisson regression analyses were used to determine the association between criminal justice contact, stressors, and obesity-related health problems among a national sample of Black adults (n = 5008). In the full model, the odds of experiencing obesity-related health problems for Black adults who had criminal justice contact was reduced (PR, 1.23 to 1.14) and not statistically significant. Black adults who reported experiencing family stressors (PR, 1.21; 95% CI, 1.08, 1.36), financial stressors (PR, 1.30; 95% CI, 1.16, 1.47), and personal stressors (PR, 1.16; 95% CI, 1.02, 1.31) were statistically significant and higher than those who reported not experiencing any of these stressors; neighborhood stressors was not statistically significant. The evidence suggests a relationship between the stressors associated with criminal justice contact and obesity-related health status. These findings emphasize the need to further explore the family, financial, and personal stressors for Black adults with criminal justice contact in order to further our understanding of their obesity-related health problems.ᅟ.

  16. Cancer Survivors’ Responses to Daily Stressors: Implications for Quality of Life

    Science.gov (United States)

    Costanzo, Erin S.; Stawski, Robert S.; Ryff, Carol D.; Coe, Christopher L.; Almeida, David M.

    2012-01-01

    Objective This study examined cancer survivors’ experience of and responses to challenges and stressors associated with every-day living. The impact of daily stressors on quality of life concerns and cortisol patterns was also investigated. Design Participants were 111 cancer survivors who participated in a national telephone diary study of daily experiences (NSDE). Their responses were compared with those of 111 sociodemographically-matched participants with no cancer history using a multilevel modeling approach. Main Outcome Measures Over an 8-day period, participants completed a daily inventory of the occurrence and impact of stressful events, affect, and physical symptoms. Salivary cortisol was sampled 4 times per day, and indices of awakening response (CAR), diurnal slope, and overall output (AUC) were examined. Results Cancer survivors experienced similar numbers and types of stressful events as the comparison group. While appraisals were largely comparable, cancer survivors showed a modest tendency to perceive stressors as more severe and disruptive, particularly those involving interpersonal tensions. The occurrence of stressors was associated with increased negative affect, decreased positive affect, and increased physical symptoms, but little change in cortisol. Relative to the comparison group, cancer survivors showed less pronounced changes in positive affect and cortisol output when stressors occurred, but a greater increase in negative affect in response to interpersonal conflicts. Conclusions Findings indicate that cancer survivors show a resilient ability to respond to day-to-day stressors and challenges. However, daily stressors can have a significant impact on survivors’ mood and physical symptoms and therefore may be an important intervention target. PMID:22268712

  17. Psychosocial stressors at work and musculoskeletal problems

    NARCIS (Netherlands)

    Houtman, I.L.D.; Bongers, P.M.; Smulders, P.G.W.; Kompier, M.A.J.

    1994-01-01

    Objectives - This paper examines the relationship between work stressors and the following health indicators: psychosomatic complaints, health behavior, and musculoskeletal problems. Methods - Secondary analyses were performed on data from the National Work and Living Condition Survey, which

  18. Impacts of air pollution and climate change on forest ecosystems - Multiple stressors and ecosystem services

    Science.gov (United States)

    The nature of scientific investigation involving hypothesis testing dictates the need to conduct controlled experiments, limiting the number of independent variables in order to identify cause and effect relationships. Single or two-factor studies are useful to identify potentia...

  19. Individual and Neighborhood Stressors, Air Pollution and Cardiovascular Disease

    Science.gov (United States)

    Hazlehurst, Marnie F.; Nurius, Paula S.; Hajat, Anjum

    2018-01-01

    Psychosocial and environmental stress exposures across the life course have been shown to be relevant in the development of cardiovascular disease (CVD). Assessing more than one stressor from different domains (e.g., individual and neighborhood) and across the life course moves us towards a more integrated picture of how stress affects health and well-being. Furthermore, these individual and neighborhood psychosocial stressors act on biologic pathways, including immune function and inflammatory response, which are also impacted by ubiquitous environmental exposures such as air pollution. The objective of this study is to evaluate the interaction between psychosocial stressors, at both the individual and neighborhood level, and air pollution on CVD. This study used data from the 2009–2011 Behavioral Risk Factor Surveillance System (BRFSS) from Washington State. Adverse childhood experiences (ACEs) measured at the individual level, and neighborhood deprivation index (NDI) measured at the zip code level, were the psychosocial stressors of interest. Exposures to three air pollutants—particulate matter (both PM2.5 and PM10) and nitrogen dioxide (NO2)—were also calculated at the zip code level. Outcome measures included several self-reported CVD-related health conditions. Both multiplicative and additive interaction quantified using the relative excess risk due to interaction (RERI), were evaluated. This study included 32,151 participants in 502 unique zip codes. Multiplicative and positive additive interactions were observed between ACEs and PM10 for diabetes, in models adjusted for NDI. The prevalence of diabetes was 1.58 (95% CI: 1.40, 1.79) times higher among those with both high ACEs and high PM10 compared to those with low ACEs and low PM10 (p-value = 0.04 for interaction on the multiplicative scale). Interaction was also observed between neighborhood-level stressors (NDI) and air pollution (NO2) for the stroke and diabetes outcomes on both multiplicative and

  20. Individual and Neighborhood Stressors, Air Pollution and Cardiovascular Disease.

    Science.gov (United States)

    Hazlehurst, Marnie F; Nurius, Paula S; Hajat, Anjum

    2018-03-08

    Psychosocial and environmental stress exposures across the life course have been shown to be relevant in the development of cardiovascular disease (CVD). Assessing more than one stressor from different domains (e.g., individual and neighborhood) and across the life course moves us towards a more integrated picture of how stress affects health and well-being. Furthermore, these individual and neighborhood psychosocial stressors act on biologic pathways, including immune function and inflammatory response, which are also impacted by ubiquitous environmental exposures such as air pollution. The objective of this study is to evaluate the interaction between psychosocial stressors, at both the individual and neighborhood level, and air pollution on CVD. This study used data from the 2009-2011 Behavioral Risk Factor Surveillance System (BRFSS) from Washington State. Adverse childhood experiences (ACEs) measured at the individual level, and neighborhood deprivation index (NDI) measured at the zip code level, were the psychosocial stressors of interest. Exposures to three air pollutants-particulate matter (both PM 2.5 and PM 10 ) and nitrogen dioxide (NO₂)-were also calculated at the zip code level. Outcome measures included several self-reported CVD-related health conditions. Both multiplicative and additive interaction quantified using the relative excess risk due to interaction (RERI), were evaluated. This study included 32,151 participants in 502 unique zip codes. Multiplicative and positive additive interactions were observed between ACEs and PM 10 for diabetes, in models adjusted for NDI. The prevalence of diabetes was 1.58 (95% CI: 1.40, 1.79) times higher among those with both high ACEs and high PM 10 compared to those with low ACEs and low PM 10 ( p -value = 0.04 for interaction on the multiplicative scale). Interaction was also observed between neighborhood-level stressors (NDI) and air pollution (NO₂) for the stroke and diabetes outcomes on both

  1. Negative Aging Attitudes Predict Greater Reactivity to Daily Stressors in Older Adults.

    Science.gov (United States)

    Bellingtier, Jennifer A; Neupert, Shevaun D

    2016-08-03

    In order to understand conflicting findings regarding the emotional reactions of older adults to daily stressors, we examined the possibility that negative aging attitudes could function as an important individual differences factor related to stressor reactivity. Using a daily dairy design, we examined the aging attitudes of 43 older adults reporting on 380 total days. Participants reported their aging attitudes on Day 1, followed by their stressor exposure and negative affect on Days 2-9. Covariates included age, gender, education, and personality. Using multilevel modeling, our results suggest that individuals with more positive aging attitudes report consistent levels of affect across study days regardless of stressors, whereas those with more negative aging attitudes reported increased emotional reactivity to daily stressors. Positive aging attitudes may serve as a resource that helps buffer reactions to daily stressors. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Nitrogen cycling process rates across urban ecosystems.

    Science.gov (United States)

    Reisinger, Alexander J; Groffman, Peter M; Rosi-Marshall, Emma J

    2016-09-21

    Nitrogen (N) pollution of freshwater, estuarine, and marine ecosystems is widespread and has numerous environmental and economic impacts. A portion of this excess N comes from urban watersheds comprised of natural and engineered ecosystems which can alter downstream N export. Studies of urban N cycling have focused on either specific ecosystems or on watershed-scale mass balances. Comparisons of specific N transformations across ecosystems are required to contextualize rates from individual studies. Here we reviewed urban N cycling in terrestrial, aquatic, and engineered ecosystems, and compared N processing in these urban ecosystem types to native reference ecosystems. We found that net N mineralization and net nitrification rates were enhanced in urban forests and riparian zones relative to reference ecosystems. Denitrification was highly variable across urban ecosystem types, but no significant differences were found between urban and reference denitrification rates. When focusing on urban streams, ammonium uptake was more rapid than nitrate uptake in urban streams. Additionally, reduction of stormwater runoff coupled with potential decreases in N concentration suggests that green infrastructure may reduce downstream N export. Despite multiple environmental stressors in urban environments, ecosystems within urban watersheds can process and transform N at rates similar to or higher than reference ecosystems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Is increasing industrialization affecting remote ecosystem health in the South Americas? Insights from ocean surface water measurements of As, Sb and Pb from a GEOTRACES transect

    Science.gov (United States)

    Weiss, Dominik; Salaun, Pascal; Van den Berg, Stan; Bi, Zaoshun

    2014-05-01

    Continued industrial development of the South Americas with increasing atmospheric emission of toxic trace metals has lead to a growing concern about possible effects on pristine ecosystem health. Concentration measurements of trace metals in ocean surface waters in the North Atlantic have successfully revealed the global extent of atmospheric pollution in the Northern Hemisphere during economical growth in the USA and Europe, suggesting a similar approach can be applied to the Southern Hemisphere. To this end, we determined concentrations of lead (Pb), antimony (Sb) and arsenic (As) using voltammetry in surface water samples of the South Atlantic Ocean collected during the third leg of the GEOTRACES West Atlantic Cruise. These elements are volatile and therefore most likely suitable tracer elements of industrial emissions from South America. The samples were not filtered and the solutions were acidified and UV digested. Total concentrations of Pb were detected. Detected As levels correspond to the sum of inorganic species (AsIII + AsV) plus the mono methyl arsenic acid (MMA) while the dimethyl arsenic acid (DMA) is not detected in such conditions. For Sb, detected levels correspond at least to the sum of inorganic fractions (SbIII + SbV). The measured concentrations for Pb varied from 6 to 23 pM. Concentrations were highest at -35° latitude and lowest at -40° and -50° latitude. We found a decreasing trend from about -35° latitude southwards. The average concentrations of As was 20 nM and of Sb 1.2 nM. Arsenic showed a more significant north to south trend than Sb. Arsenic concentration was highest at -23 ° latitude (21 nM) and the lowest at -43 ° latitude (17.7 nM). Antimony concentration was highest at -31 ° latitude (1.5 nM) and lowest at -35 ° latitude (1.0 nM). Our preliminary data suggests that the major industrial centres in Brazil (i.e., Sao Paolo, Rio de Janeiro) and Argentina (i.e., Buenos Aires) affect atmospheric metal fluxes to remote

  4. Responses of Spartina alterniflora to Multiple Stressors: Changing Precipitation Patterns, Accelerated Sea Level Rise, and Nutrient Enrichment

    Science.gov (United States)

    Coastal wetlands, well recognized for their ecosystem services, have faced many threats throughout the United States and elsewhere. Managers require good information on responses of wetlands to the combined stressors that these habitats experience, or may in the future as a resul...

  5. Nursing students in Iran identify the clinical environment stressors.

    Science.gov (United States)

    Najafi Doulatabad, Shahla; Mohamadhosaini, Sima; Ghafarian Shirazi, Hamid Reza; Mohebbi, Zinat

    2015-06-01

    Stress at clinical environment is one of the cases that could affect the education quality among nursing students. The study aims to investigate Iranian nursing students' perceptions on the stressors in clinical environment in the South Western part of Iran. A cross-sectional descriptive study was conducted in 2010 to include 300 nursing students after their completion of second clinical nursing course in a hospital environment. Data were collected using a researcher-made questionnaire, with focus on the clinical environment stressors from personal, educational and training viewpoints. Data analysis was performed using SPSS software (IBM Corporation, Armonk, NY, USA) and descriptive statistics tests. Among the various stressors, the highest scores were given to the faculty (71 ± 19.77), followed by the students' personal characteristics (43.15 ± 21.79). Given that faculty-related factors provoked more stress in nursing students, nursing administration should diligently evaluate and improve communication skills among faculty to reduce student stress and enhance learning. © 2014 Wiley Publishing Asia Pty Ltd.

  6. Acute Stressor Effects on Goal-Directed Action in Rats

    Science.gov (United States)

    Braun, Stephanie; Hauber, Wolfgang

    2013-01-01

    Here we examined effects of acute stressors that involve either systemic coadministration of corticosterone/yohimbine (3 mg/kg each) to increase glucocorticoid/noradrenaline activity (denoted as "pharmacological" stressor) or one or several distinct restraint stressors (denoted as "single" vs. "multiple" stressor) on…

  7. Relations between groundwater levels and anthropogenic and meteorological stressors at selected sites in east-central Florida, 1995-2007

    Science.gov (United States)

    Murray, Louis C.

    2010-01-01

    Multivariate linear regression analyses were used to define the relations of water levels in the Upper Floridan aquifer (UFA) and surficial aquifer system (SAS) to anthropogenic and meteorological stressors between 1995 and 2007 at two monitoring well sites (Charlotte Street and Lake Oliver) in east-central Florida. Anthropogenic stressors of interest included municipal and agricultural groundwater withdrawals, and application of reclaimed-water to rapid-infiltration basins (source of aquifer recharge). Meteorological stressors included precipitation and potential evapotranspiration. Overall, anthropogenic and meteorological stressors accounted for about 40 to 89 percent of the variance in UFA and SAS groundwater levels and water-level changes. While mean monthly water levels were better correlated with monthly stressor values, changes in UFA and SAS water levels were better correlated with changes in stressor values. Water levels and water-level changes were influenced by system persistence as the moving-averaged values of both stressor types, which accounted for the influence of the previous month(s) conditions, consistently yielded higher adjusted coefficients of determination (R2 adj) values than did single monthly values. While monthly water-level changes tend to be influenced equally with both stressors across the hydrologically averaged 13-year period, changes were more influenced by one stressor or the other seasonally and during extended wet and dry periods. Seasonally, UFA water-level changes tended to be more influenced by anthropogenic stressors than by meteorological stressors, while changes in SAS water levels tended to be more influenced by meteorological stressors. During extended dry periods (12 months or greater), changes in UFA water levels at Charlotte Street were more affected by anthropogenic stressors than by meteorological stressors, while changes in SAS levels were more affected by meteorological stressors. At Lake Oliver, changes in both

  8. Police work stressors and cardiac vagal control.

    Science.gov (United States)

    Andrew, Michael E; Violanti, John M; Gu, Ja K; Fekedulegn, Desta; Li, Shengqiao; Hartley, Tara A; Charles, Luenda E; Mnatsakanova, Anna; Miller, Diane B; Burchfiel, Cecil M

    2017-09-10

    This study examines relationships between the frequency and intensity of police work stressors and cardiac vagal control, estimated using the high frequency component of heart rate variability (HRV). This is a cross-sectional study of 360 officers from the Buffalo New York Police Department. Police stress was measured using the Spielberger police stress survey, which includes exposure indices created as the product of the self-evaluation of how stressful certain events were and the self-reported frequency with which they occurred. Vagal control was estimated using the high frequency component of resting HRV calculated in units of milliseconds squared and reported in natural log scale. Associations between police work stressors and vagal control were examined using linear regression for significance testing and analysis of covariance for descriptive purposes, stratified by gender, and adjusted for age and race/ethnicity. There were no significant associations between police work stressor exposure indices and vagal control among men. Among women, the inverse associations between the lack of support stressor exposure and vagal control were statistically significant in adjusted models for indices of exposure over the past year (lowest stressor quartile: M = 5.57, 95% CI 5.07 to 6.08, and highest stressor quartile: M = 5.02, 95% CI 4.54 to 5.51, test of association from continuous linear regression of vagal control on lack of support stressor β = -0.273, P = .04). This study supports an inverse association between lack of organizational support and vagal control among female but not male police officers. © 2017 Wiley Periodicals, Inc.

  9. Reconceptualizing synergism and antagonism among multiple stressors.

    Science.gov (United States)

    Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D

    2015-04-01

    The potential for complex synergistic or antagonistic interactions between multiple stressors presents one of the largest uncertainties when predicting ecological change but, despite common use of the terms in the scientific literature, a consensus on their operational definition is still lacking. The identification of synergism or antagonism is generally straightforward when stressors operate in the same direction, but if individual stressor effects oppose each other, the definition of synergism is paradoxical because what is synergistic to one stressor's effect direction is antagonistic to the others. In their highly cited meta-analysis, Crain et al. (Ecology Letters, 11, 2008: 1304) assumed in situations with opposing individual effects that synergy only occurs when the cumulative effect is more negative than the additive sum of the opposing individual effects. We argue against this and propose a new systematic classification based on an additive effects model that combines the magnitude and response direction of the cumulative effect and the interaction effect. A new class of "mitigating synergism" is identified, where cumulative effects are reversed and enhanced. We applied our directional classification to the dataset compiled by Crain et al. (Ecology Letters, 11, 2008: 1304) to determine the prevalence of synergistic, antagonistic, and additive interactions. Compared to their original analysis, we report differences in the representation of interaction classes by interaction type and we document examples of mitigating synergism, highlighting the importance of incorporating individual stressor effect directions in the determination of synergisms and antagonisms. This is particularly pertinent given a general bias in ecology toward investigating and reporting adverse multiple stressor effects (double negative). We emphasize the need for reconsideration by the ecological community of the interpretation of synergism and antagonism in situations where

  10. Effects on alcohol use and anxiety of the September 11, 2001, attacks and chronic work stressors: a longitudinal cohort study.

    Science.gov (United States)

    Richman, Judith A; Wislar, Joseph S; Flaherty, Joseph A; Fendrich, Michael; Rospenda, Kathleen M

    2004-11-01

    We hypothesized that chronic stressors associated with an everyday social role (work) would interact with a traumatic macrosocial stressor (the terrorist attacks of September 11, 2001) in predicting mental health status (during the fall of 2001). We used mail surveys returned as part of wave 3 of a workplace cohort study, both before and after September 11, 2001, to assess decision latitude, sexual harassment, generalized workplace abuse, psychological distress, and alcohol use. We also used regression analyses to assess the main effect of September 11 and interactions between September 11 and stressors, after control for baseline mental health. The main effect of September 11 on elevated alcohol use was significant for women but not for men. For women, work stressors significantly interacted with experiencing the events of September 11 to affect alcohol use and anxiety outcomes. Women experiencing chronic work stressors were most vulnerable to elevated psychological distress and alcohol use after September 11, 2001.

  11. Identifying Stressors and Reactions to Stressors in Gifted and Non-Gifted Students

    Science.gov (United States)

    Amini, Marzieh

    2005-01-01

    Using the Student Life Stress Inventory and the Coopersmith Self-Esteem Inventory, stressors and reactions to stressors were identified in gifted high school students and compared with non-gifted students. Altogether, 340 boys and girls (156 gifted and 184 non-gifted students) from four high schools in Shiraz (two high schools for gifted and two…

  12. Aquatic biodiversity in forests: A weak link in ecosystem services resilience

    Science.gov (United States)

    Penaluna, Brooke E.; Olson, Deanna H.; Flitcroft, Rebecca L; Weber, Matthew A.; Bellmore, J. Ryan; Wondzell, Steven M.; Dunham, Jason B.; Johnson, Sherri L.; Reeves, Gordon H.

    2017-01-01

    The diversity of aquatic ecosystems is being quickly reduced on many continents, warranting a closer examination of the consequences for ecological integrity and ecosystem services. Here we describe intermediate and final ecosystem services derived from aquatic biodiversity in forests. We include a summary of the factors framing the assembly of aquatic biodiversity in forests in natural systems and how they change with a variety of natural disturbances and human-derived stressors. We consider forested aquatic ecosystems as a multi-state portfolio, with diverse assemblages and life-history strategies occurring at local scales as a consequence of a mosaic of habitat conditions and past disturbances and stressors. Maintaining this multi-state portfolio of assemblages requires a broad perspective of ecosystem structure, various functions, services, and management implications relative to contemporary stressors. Because aquatic biodiversity provides multiple ecosystem services to forests, activities that compromise aquatic ecosystems and biodiversity could be an issue for maintaining forest ecosystem integrity. We illustrate these concepts with examples of aquatic biodiversity and ecosystem services in forests of northwestern North America, also known as Northeast Pacific Rim. Encouraging management planning at broad as well as local spatial scales to recognize multi-state ecosystem management goals has promise for maintaining valuable ecosystem services. Ultimately, integration of information from socio-ecological ecosystems will be needed to maintain ecosystem services derived directly and indirectly from forest aquatic biota.

  13. How stressors are dynamically appraised within a team during a game: An exploratory study in basketball.

    Science.gov (United States)

    Doron, J; Bourbousson, J

    2017-12-01

    Little is known about how team sport athletes individually and collectively experience sources of stress during competitive sport encounters. This study aimed to examine the nature of the stressors team sport athletes appraised during games at individual and team levels, as well as their degree of synchronization during an unfolding game. Through individual self-confrontation interviews, the activities of nine basketball players of the same team were examined in detail. The results revealed that 12 categories of stressors were reported, and categorized into two larger units reflecting stressors perceived as affecting (a) "the team functioning as a whole" and (b) "a player's own functioning". Thus, the nature and degree of similarity of the game-specific stressors experienced by basketball players within a single team were identified during a game. In addition, the findings showed six different patterns of synchronizations of team members' stressors, as well as their changes over the course of the game. They provided support for the synchronized appraisal and experience of stressors within a team during a game. By adopting an interpersonal perspective and examining the temporal interplay in team members' activities, this study shed light on stress within teams. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Reported Exposure and Emotional Reactivity to Daily Stressors: The Roles of Adult-Age and Global Perceived Stress

    Science.gov (United States)

    Stawski, Robert S.; Sliwinski, Martin J.; Almeida, David M.; Smyth, Joshua M.

    2012-01-01

    A central goal of daily stress research is to identify resilience and vulnerability factors associated with exposure and reactivity to daily stressors. The current study examined how age differences and global perceptions of stress relate to exposure and emotional reactivity to daily stressors. Sixty-seven younger (Mage = 20) and 116 older (Mage = 80) adults completed a daily stress diary and measures of positive and negative affect on 6 days over a 14 day period. Participants also completed a measure of global perceived stress. Results revealed that reported exposure to daily stressors is reduced in old age, but that emotional reactivity to daily stressors did not differ between young and older adults. Global perceived stress was associated with greater reported exposure to daily stressors in old adults, and greater stress-related increases in negative affect in younger adults. Furthermore, across days on which daily stressors were reported, intraindividual variability in the number and severity of stressors reported was associated with increased negative affect, but only among younger adults. PMID:18361654

  15. Reported exposure and emotional reactivity to daily stressors: the roles of adult age and global perceived stress.

    Science.gov (United States)

    Stawski, Robert S; Sliwinski, Martin J; Almeida, David M; Smyth, Joshua M

    2008-03-01

    A central goal of daily stress research is to identify resilience and vulnerability factors associated with exposure and reactivity to daily stressors. The present study examined how age differences and global perceptions of stress relate to exposure and emotional reactivity to daily stressors. Sixty-seven younger (M age = 20) and 116 older (M age = 80) adults completed a daily stress diary and measures of positive and negative affect on 6 days over a 14-day period. Participants also completed a measure of global perceived stress. Results revealed that reported exposure to daily stressors is reduced in old age but that emotional reactivity to daily stressors did not differ between younger and older adults. Global perceived stress was associated with greater reported exposure to daily stressors in older adults and greater stress-related increases in negative affect in younger adults. Furthermore, across days on which daily stressors were reported, intraindividual variability in the number and severity of stressors reported was associated with increased negative affect, but only among younger adults. (c) 2008 APA, all rights reserved.

  16. An improved null model for assessing the net effects of multiple stressors on communities.

    Science.gov (United States)

    Thompson, Patrick L; MacLennan, Megan M; Vinebrooke, Rolf D

    2018-01-01

    Ecological stressors (i.e., environmental factors outside their normal range of variation) can mediate each other through their interactions, leading to unexpected combined effects on communities. Determining whether the net effect of stressors is ecologically surprising requires comparing their cumulative impact to a null model that represents the linear combination of their individual effects (i.e., an additive expectation). However, we show that standard additive and multiplicative null models that base their predictions on the effects of single stressors on community properties (e.g., species richness or biomass) do not provide this linear expectation, leading to incorrect interpretations of antagonistic and synergistic responses by communities. We present an alternative, the compositional null model, which instead bases its predictions on the effects of stressors on individual species, and then aggregates them to the community level. Simulations demonstrate the improved ability of the compositional null model to accurately provide a linear expectation of the net effect of stressors. We simulate the response of communities to paired stressors that affect species in a purely additive fashion and compare the relative abilities of the compositional null model and two standard community property null models (additive and multiplicative) to predict these linear changes in species richness and community biomass across different combinations (both positive, negative, or opposite) and intensities of stressors. The compositional model predicts the linear effects of multiple stressors under almost all scenarios, allowing for proper classification of net effects, whereas the standard null models do not. Our findings suggest that current estimates of the prevalence of ecological surprises on communities based on community property null models are unreliable, and should be improved by integrating the responses of individual species to the community level as does our

  17. Environmental stressors as a driver of the trait composition of benthic macroinvertebrate assemblages in polluted Iberian rivers.

    Science.gov (United States)

    Kuzmanovic, Maja; Dolédec, Sylvain; de Castro-Catala, Nuria; Ginebreda, Antoni; Sabater, Sergi; Muñoz, Isabel; Barceló, Damià

    2017-07-01

    We used the trait composition of macroinvertebrate communities to identify the effects of pesticides and multiple stressors associated with urban land use at different sites of four rivers in Spain. Several physical and chemical stressors (high metal pollution, nutrients, elevated temperature and flow alterations) affected the urban sites. The occurrence of multiple stressors influenced aquatic assemblages at 50% of the sites. We hypothesized that the trait composition of macroinvertebrate assemblages would reflect the strategies that the assemblages used to cope with the respective environmental stressors. We used RLQ and fourth corner analysis to address the relationship between stressors and the trait composition of benthic macroinvertebrates. We found a statistically significant relationship between the trait composition and the exposure of assemblages to environmental stressors. The first RLQ dimension, which explained most of the variability, clearly separated sites according to the stressors. Urban-related stressors selected taxa that were mainly plurivoltine and fed on deposits. In contrast, pesticide impacted sites selected taxa with high levels of egg protection (better egg survival), indicating a potentially higher risk for egg mortality. Moreover, the trait diversity of assemblages at urban sites was low compared to that observed in pesticide impacted sites, suggesting the homogenization of assemblages in urban areas. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Entrepreneurial Ecosystems

    NARCIS (Netherlands)

    Stam, F.C.; Spigel, Ben

    2016-01-01

    This paper reviews and discusses the emergent entrepreneurial ecosystem approach. Entrepreneurial ecosystems are defined as a set of interdependent actors and factors coordinated in such a way that they enable productive entrepreneurship within a particular territory. The purpose of this paper is to

  19. Bioaccumulation of selected heavy metals by the water fern, Azolla filiculoides Lam. in a wetland ecosystem affected by sewage, mine and industrial pollution

    Energy Technology Data Exchange (ETDEWEB)

    Wet, L.P.D. de; Schoonbee, H.J.; Pretorius, J.; Bezuidenhout, L.M. (Rand Afrikaans University, Johannesburg (South Africa). Depts. of Zoology and Botany, Research Unit for Aquatic and Terrestrial Ecosystems)

    1990-10-01

    The bio-accumulation of the heavy metals, Fe, Cu, Ni, Pb, Zn, Mn and Cr by the water fern, Azolla filiculoides Lam. in a wetland ecosystem polluted by effluents from sewage works, mines and industries was investigated. Results showed that the different metals can be accumulated by the water fern at concentration levels not necessarily related to their actual concentrations in the aquatic environment, as measured in this case, in the bottom sediments. 45 refs., 1 fig., 3 tabs.

  20. How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Ying [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation; Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Xu, Zhihong; Reverchon, Frederique [Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Luo, Yongming [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation

    2012-03-15

    Global climate change (GCC), especially global warming, has affected the material cycling (e.g., carbon, nutrients, and organic chemicals) and the energy flows of terrestrial ecosystems. Persistent organic pollutants (POPs) were regarded as anthropogenic organic carbon (OC) source, and be coupled with the natural carbon (C) and nutrient biogeochemical cycling in ecosystems. The objective of this work was to review the current literature and explore potential coupling processes and mechanisms between POPs and biogeochemical cycles of C and nutrients in terrestrial ecosystems induced by global warming. Global warming has caused many physical, chemical, and biological changes in terrestrial ecosystems. POPs environmental fate in these ecosystems is controlled mainly by temperature and biogeochemical processes. Global warming may accelerate the re-emissions and redistribution of POPs among environmental compartments via soil-air exchange. Soil-air exchange is a key process controlling the fate and transportation of POPs and terrestrial ecosystem C at regional and global scales. Soil respiration is one of the largest terrestrial C flux induced by microbe and plant metabolism, which can affect POPs biotransformation in terrestrial ecosystems. Carbon flow through food web structure also may have important consequences for the biomagnification of POPs in the ecosystems and further lead to biodiversity loss induced by climate change and POPs pollution stress. Moreover, the integrated techniques and biological adaptation strategy help to fully explore the coupling mechanisms, functioning and trends of POPs and C and nutrient biogeochemical cycling processes in terrestrial ecosystems. There is increasing evidence that the environmental fate of POPs has been linked with biogeochemical cycles of C and nutrients in terrestrial ecosystems under GCC. However, the relationships between POPs and the biogeochemical cycles of C and nutrients are still not well understood. Further

  1. PROFILE: Integrating Stressor and Response Monitoring into a Resource-Based Water-Quality Assessment Framework.

    Science.gov (United States)

    ROUX; KEMPSTER; KLEYNHANS; VAN; DU

    1999-01-01

    / South African water law as well as the country's water resource management policies are currently under review. The Water Law Principles, which were established as part of this review process, indicate a commitment to sustainable development of water resources and the protection of an ecological "reserve." Such policy goals highlight the limitations of traditional and current water-quality management strategies, which rely on stressor monitoring and associated regulation of pollution. The concept of an assimilative capacity is central to the implementation of the current water-quality management approach. Weaknesses inherent in basing water management on the concept of assimilative capacity are discussed. Response monitoring is proposed as a way of addressing some of the weaknesses. Following a global trend, the new policy goals emphasize the need to protect rather than to use the ability of ecosystems to recover from disturbances. This necessitates the adoption of response measurements to quantify ecological condition and monitor ecological change. Response monitoring focuses on properties that are essential to the sustainability of the ecosystem. These monitoring tools can be used to establish natural ranges of ecological change within ecosystems, as well as to quantify conceptually acceptable and unacceptable ranges of change. Through a framework of biological criteria and biological impairment standards, the results of response monitoring can become an integral part of future water resource management strategies in South Africa. KEY WORDS: Stressor monitoring; Response monitoring; Assimilative capacity; Ecosystem stability; Resilience; Biocriteria

  2. Combined effects of local habitat, anthropogenic stress, and dispersal on stream ecosystems: a mesocosm experiment.

    Science.gov (United States)

    Turunen, Jarno; Louhi, Pauliina; Mykrä, Heikki; Aroviita, Jukka; Putkonen, Emmi; Huusko, Ari; Muotka, Timo

    2018-06-06

    The effects of anthropogenic stressors on community structure and ecosystem functioning can be strongly influenced by local habitat structure and dispersal from source communities. Catchment land uses increase the input of fine sediments into stream channels, clogging the interstitial spaces of benthic habitats. Aquatic macrophytes enhance habitat heterogeneity and mediate important ecosystem functions, being thus a key component of habitat structure in many streams. Therefore, the recovery of macrophytes following in-stream habitat modification may be prerequisite for successful stream restoration. Restoration success is also affected by dispersal of organisms from the source community, with potentially strongest responses in relatively isolated headwater sites that receive limited amount of dispersing individuals. We used a factorial design in a set of stream mesocosms to study the independent and combined effects of an anthropogenic stressor (sand sedimentation), local habitat (macrophytes, i.e. moss transplants) and enhanced dispersal (two levels: high vs. low) on organic matter retention, algal accrual rate, leaf decomposition and macroinvertebrate community structure. Overall, all responses were simple additive effects with no interactions between treatments. Sand reduced algal accumulation, total invertebrate density and density of a few individual taxa. Mosses reduced algal accrual rate and algae-grazing invertebrates, but enhanced organic matter retention and detritus- and filter-feeders. Mosses also reduced macroinvertebrate diversity by increasing the dominance by a few taxa. Mosses also reduced leaf-mass loss, possibly because the organic matter retained by mosses provided an additional food source for leaf-shredding invertebrates and thus reduced shredder aggregation into leaf packs. The effect of mosses on macroinvertebrate communities and ecosystem functioning was distinct irrespective of the level of dispersal, suggesting strong environmental

  3. Psychosocial stressors of sickle cell disease on adult patients in Cameroon.

    Science.gov (United States)

    Wonkam, Ambroise; Mba, Caryl Zameyo; Mbanya, Dora; Ngogang, Jeanne; Ramesar, Raj; Angwafo, Fru F

    2014-12-01

    Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face-to-face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36-item stress factors scale evaluating general perceptions of stress and five main stressors' domain: disease factors, hospital factors, financial factors, family factors and quality of personal-life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non-parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20-30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8% had >3 painful vaso-oclusive crises annually. Only 4.8% had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The "degree of clinical severity" category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors' categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health-care and practices to reduce SCD morbidity and improve patients' quality of life.

  4. Ecosystem thermodynamics

    International Nuclear Information System (INIS)

    Gomez Palacio, German Rau

    1998-01-01

    Ecology is no more a descriptive and self-sufficient science. Many viewpoints are needed simultaneously to give a full coverage of such complex systems: ecosystems. These viewpoints come from physics, chemistry, and nuclear physics, without a new far from equilibrium thermodynamics and without new mathematical tools such as catastrophe theory, fractal theory, cybernetics and network theory, the development of ecosystem science would never have reached the point of today. Some ideas are presented about the importance that concept such as energy, entropy, exergy information and none equilibrium have in the analysis of processes taking place in ecosystems

  5. Determining ecoregional numeric nutrient criteria by stressor-response models in Yungui ecoregion lakes, China.

    Science.gov (United States)

    Huo, Shouliang; Ma, Chunzi; Xi, Beidou; Tong, Zhonghua; He, Zhuoshi; Su, Jing; Wu, Fengchang

    2014-01-01

    The importance of developing numeric nutrient criteria has been recognized to protect the designated uses of water bodies from nutrient enrichment that is associated with broadly occurring levels of nitrogen/phosphorus pollution. The identification and estimation of stressor-response models in aquatic ecosystems has been shown to be useful in the determination of nutrient criteria. In this study, three methods based on stressor-response relationships were applied to determine nutrient criteria for Yungui ecoregion lakes with respect to total phosphorus (TP), total nitrogen (TN), and planktonic chlorophyll a (Chl a). Simple linear regression (SLR) models were established to provide an estimate of the relationship between a response variable and a stressor. Multiple linear regressions were used to simultaneously estimate the effect of TP and TN on Chl a. A morphoedaphic index (MEI) was applied to derive nutrient criteria using data from Yungui ecoregion lakes, which were considered as areas with less anthropogenic influences. Nutrient criteria, as determined by these three methods, showed broad agreement for all parameters. The ranges of numeric nutrient criteria for Yungui ecoregion lakes were determined as follows: TP 0.008-0.010 mg/L and TN 0.140-0.178 mg/L. The stressor-response analysis described will be of benefit to support countries in their numeric criteria development programs and to further the goal of reducing nitrogen/phosphorus pollution in China.

  6. Towards ecosystem-based management

    NARCIS (Netherlands)

    Tam, Jamie C.; Link, Jason S.; Rossberg, Axel G.; Rogers, Stuart I.; Levin, Philip S.; Rochet, Marie-Joelle; Bundy, Alida; Belgrano, Andrea; Libralato, Simone; Tomczak, Maciej; Wolfshaar, van de K.E.; Pranovi, Fabio; Gorokhova, Elena; Large, Scott I.; Niquil, Nathalie; Greenstreet, Simon P.R.; Druon, Jean-Noel; Lesutiene, Jurate; Johansen, Marie; Preciado, Izaskun; Patricio, Joana; Palialexis, Andreas; Tett, Paul; Johansen, Geir O.; Houle, Jennifer; Rindorf, Anna

    2017-01-01

    Modern approaches to Ecosystem-Based Management and sustainable use of marine resources must account for the myriad of pressures (interspecies, human and environmental) affecting marine ecosystems. The network of feeding interactions between co-existing species and populations (food webs) are an

  7. Childhood Stress : Stressors, Coping, and Factors.

    NARCIS (Netherlands)

    Nijboer, J.M.

    2007-01-01

    Burnout is a matter of imbalance in life very often (Nijboer, 2006). In order to know more about imbalance and exhaustion in children, stress and coping in children will be investigated in this literature study. The goal is to identify common childhood stressors, the ways children cope with stress,

  8. INCORPORATING NONCHEMICAL STRESSORS INTO CUMMULATIVE RISK ASSESSMENTS

    Science.gov (United States)

    The risk assessment paradigm has begun to shift from assessing single chemicals using "reasonable worst case" assumptions for individuals to considering multiple chemicals and community-based models. Inherent in community-based risk assessment is examination of all stressors a...

  9. Habituation to a stressor predicts adolescents' adiposity

    Science.gov (United States)

    Background and Objectives: Stress is associated with gains in adiposity. One factor that determines how much stress is experienced is how quickly an adolescent reduces responding (habituates) across repeated stressors. The purpose of this study was to determine the association of body mass index pe...

  10. Overview of Atherosclerosis and Chemical Stressors

    Science.gov (United States)

    Dr. Cascio’s presentation at the workshop titled, “titled “Understanding the Combined Effects of Environmental Chemical and Non-Chemical Stressors: Atherosclerosis as a Model” will highlight atherosclerosis’s rapidly growing role as a cause of increa...

  11. Daily Stressors in Primary Education Students

    Science.gov (United States)

    Fernández-Baena, F. Javier; Trianes, María V.; Escobar, Milagros; Blanca, María J.; Muñoz, Ángela M.

    2015-01-01

    Daily stress can have a bearing on children's emotional and academic development. This study aimed to assess daily stressors and to determine their prevalence among primary education students, taking into account their gender, academic year, social adaptation, and the school location. A sample of 7,354 Spanish schoolchildren aged between 6 and 13…

  12. District Stressors and Teacher Evaluation Ratings

    Science.gov (United States)

    Lenhoff, Sarah Winchell; Pogodzinski, Ben; Mayrowetz, David; Superfine, Benjamin Michael; Umpstead, Regina R.

    2018-01-01

    Purpose: Federal and state policymakers in the USA have sought to better differentiate the performance of K-12 teachers by enacting more rigorous evaluation policies. The purpose of this paper is to investigate whether these policies are working as intended and explore whether district stressors such as funding, enrollment, and governance are…

  13. Urban ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Duvigneaud, P

    1974-01-01

    The author considers the town as an ecosystem. He examines its various subdivisions (climate, soil, structure, human and non-human communities, etc.) for which he chooses examples with particular reference to the city of Brussels.

  14. Abiotic stressors and stress responses: What commonalities appear between species across biological organization levels?

    International Nuclear Information System (INIS)

    Sulmon, Cécile; Baaren, Joan van; Cabello-Hurtado, Francisco; Gouesbet, Gwenola; Hennion, Françoise; Mony, Cendrine; Renault, David; Bormans, Myriam; El Amrani, Abdelhak; Wiegand, Claudia; Gérard, Claudia

    2015-01-01

    Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental complexity. We provide new insights into the understanding of the impact of molecular and cellular responses on individual and population dynamics and assess the potential related effects on communities and ecosystem functioning. - Highlights: • Responses to chemical and thermal stressors are reviewed across organization levels. • Common responses between taxa are evident at the molecular and cellular scales. • At individual level, energy allocation connects species-specific stress responses. • Commonality decreases at higher levels due to increasing environmental complexity. - The commonality of stress responses to chemical and thermal stressors among taxa is evident at the molecular and cellular scales but remains unclear at higher levels of organization

  15. Richness, biomass, and nutrient content of a wetland macrophyte community affect soil nitrogen cycling in a diversity-ecosystem functioning experiment

    Science.gov (United States)

    Korol, Alicia R.; Ahn, Changwoo; Noe, Gregory

    2016-01-01

    The development of soil nitrogen (N) cycling in created wetlands promotes the maturation of multiple biogeochemical cycles necessary for ecosystem functioning. This development proceeds from gradual changes in soil physicochemical properties and influential characteristics of the plant community, such as competitive behavior, phenology, productivity, and nutrient composition. In the context of a 2-year diversity experiment in freshwater mesocosms (0, 1, 2, 3, or 4 richness levels), we assessed the direct and indirect impacts of three plant community characteristics – species richness, total biomass, and tissue N concentration – on three processes in the soil N cycle – soil net ammonification, net nitrification, and denitrification potentials. Species richness had a positive effect on net ammonification potential (NAP) through higher redox potentials and likely faster microbial respiration. All NAP rates were negative, however, due to immobilization and high rates of ammonium removal. Net nitrification was inhibited at higher species richness without mediation from the measured soil properties. Higher species richness also inhibited denitrification potential through increased redox potential and decreased nitrification. Both lower biomass and/or higher tissue ratios of carbon to nitrogen, characteristics indicative of the two annual plants, were shown to have stimulatory effects on all three soil N processes. The two mediating physicochemical links between the young macrophyte community and microbial N processes were soil redox potential and temperature. Our results suggest that early-successional annual plant communities play an important role in the development of ecosystem N multifunctionality in newly created wetland soils.

  16. Stressors and their Influence on Job Performance of Career ...

    African Journals Online (AJOL)

    Stressors and their Influence on Job Performance of Career Administrative Staff in ... African Research Review ... Abstract. The purpose of this study was to determine stressors and how they influence university career administrative staff in the ...

  17. Community Level Stressors and Their Impacts on Food Contamination

    Science.gov (United States)

    Research is needed to understand a community’s food resources, utilization of those resources, and how the built and natural environment impact access to resources and potential chemical exposures. This research will identify stressors, relationships between those stressors...

  18. Work environment stressors and personnel efficacy in Nigeria's ...

    African Journals Online (AJOL)

    Work environment stressors and personnel efficacy in Nigeria's maritime industry. ... Journal Home > Vol 15, No 1 (2017) > ... employees and corporate organizations need to manage stress by identifying the stressors and stress levels.

  19. Reactivity to Daily Stressors in Adulthood: The Importance of Stressor Type in Characterizing Risk Factors

    OpenAIRE

    Hay, Elizabeth L.; Diehl, Manfred

    2010-01-01

    This study examined daily stressors in adults aged 18 to 89 years (M = 49.6 years) over 30 days. We examined the role of individual factors (i.e., age, self-concept differentiation, perceived control) in physical and psychological reactivity to interpersonal, network, home, and health stressors. Findings were consistent with the perspective that adults were less reactive to stress on days they felt in control and that younger adults and adults with high self-concept differentiation (SCD) were...

  20. Reported Exposure and Emotional Reactivity to Daily Stressors: The Roles of Adult-Age and Global Perceived Stress

    OpenAIRE

    Stawski, Robert S.; Sliwinski, Martin J.; Almeida, David M.; Smyth, Joshua M.

    2008-01-01

    A central goal of daily stress research is to identify resilience and vulnerability factors associated with exposure and reactivity to daily stressors. The current study examined how age differences and global perceptions of stress relate to exposure and emotional reactivity to daily stressors. Sixty-seven younger (Mage = 20) and 116 older (Mage = 80) adults completed a daily stress diary and measures of positive and negative affect on 6 days over a 14 day period. Participants also completed ...

  1. Shared effects of organic microcontaminants and environmental stressors on biofilms and invertebrates in impaired rivers

    International Nuclear Information System (INIS)

    Sabater, S.; Barceló, D.; De Castro-Català, N.; Ginebreda, A.; Kuzmanovic, M.; Petrovic, M.; Picó, Y.; Ponsatí, L.; Tornés, E.; Muñoz, I.

    2016-01-01

    Land use type, physical and chemical stressors, and organic microcontaminants were investigated for their effects on the biological communities (biofilms and invertebrates) in several Mediterranean rivers. The diversity of invertebrates, and the scores of the first principal component of a PCA performed with the diatom communities were the best descriptors of the distribution patterns of the biological communities against the river stressors. These two metrics decreased according to the progressive site impairment (associated to higher area of agricultural and urban-industrial, high water conductivity, higher dissolved organic carbon and dissolved inorganic nitrogen concentrations, and higher concentration of organic microcontaminants, particularly pharmaceutical and industrial compounds). The variance partition analyses (RDAs) attributed the major share (10%) of the biological communities' response to the environmental stressors (nutrients, altered discharge, dissolved organic matter), followed by the land use occupation (6%) and of the organic microcontaminants (2%). However, the variance shared by the three groups of descriptors was very high (41%), indicating that their simultaneous occurrence determined most of the variation in the biological communities. - Highlights: • River impairment was associated to increasing agricultural and urban-industrial areas, and sites were having waters with high water conductivity and nutrient concentrations, and higher concentrations of organic microcontaminants, particularly pharmaceutical and alkylphenol compounds. • Physico-chemical stressors (high nutrients and dissolved organic matter, altered water flow) were the ones mostly affecting biodiversity. • The simultaneous occurrence of microcontaminants with physico-chemical stressors in urban-industrial areas produced a much higher effect than the simple addition of stressors. - Organic microcontaminants reinforce the effects of environmental and land use stressors on

  2. Daily stressors, trauma exposure, and mental health among stateless Rohingya refugees in Bangladesh.

    Science.gov (United States)

    Riley, Andrew; Varner, Andrea; Ventevogel, Peter; Taimur Hasan, M M; Welton-Mitchell, Courtney

    2017-06-01

    The Rohingya of Myanmar are a severely persecuted minority who form one of the largest groups of stateless people; thousands of them reside in refugee camps in southeastern Bangladesh. There has been little research into the mental health consequences of persecution, war, and other historical trauma endured by the Rohingya; nor has the role of daily environmental stressors associated with continued displacement, statelessness, and life in the refugee camps, been thoroughly researched. This cross-sectional study examined: trauma history, daily environmental stressors, and mental health outcomes for 148 Rohingya adults residing in Kutupalong and Nayapara refugee camps in Bangladesh. Results indicated high levels of mental health concerns: posttraumatic stress disorder (PTSD), depression, somatic complaints, and associated functional impairment. Participants also endorsed local idioms of distress, including somatic complaints and concerns associated with spirit possession. The study also found very high levels of daily environmental stressors associated with life in the camps, including problems with food, lack of freedom of movement, and concerns regarding safety. Regression and associated mediation analyses indicated that, while there was a direct effect of trauma exposure on mental health outcomes (PTSD symptoms), daily environmental stressors partially mediated this relationship. Depression symptoms were associated with daily stressors, but not prior trauma exposure. These findings indicate that daily stressors play a pivotal role in mental health outcomes of populations affected by collective violence and statelessness. It is, therefore, important to consider the role and effects of environmental stressors associated with life in refugee camps on the mental health and psychosocial well-being of stateless populations such as the Rohingya, living in protracted humanitarian environments.

  3. Coping with Work Stressors in Nursing. Effects of Adaptive versus Maladaptive Strategies.

    Science.gov (United States)

    Parasuraman, Saroj; Hansen, Donna

    1987-01-01

    The effect of coping behaviors on nurses' affective reactions to work-generated stressors was assessed, using data gathered from 215 nurses in a medical center hospital in the Midwest. Adaptive coping, reflecting problem-solving behaviors, was found to moderate the relationships of work overload and resource inadequacy with felt stress. (Author/CH)

  4. Stressors Experienced by Nursing Students Enrolled in Baccalaureate Second Degree Accelerated Registered Nursing Programs

    Science.gov (United States)

    Bell, Charlene

    2017-01-01

    A mounting concern throughout the country is a current and growing nursing shortage. In order to meet the growing demand of nurses, many colleges have created baccalaureate second degree accelerated registered nursing programs. Stressors, experienced by nursing students in these accelerated programs, may affect their retention. A deeper…

  5. APPROACHES FOR INCORPORATING NON-CHEMICAL STRESSORS INTO CUMULATIVE RISK ASSESSMENTS

    Science.gov (United States)

    Over the past twenty years, the risk assessment paradigm has gradually shifted from an individual chemical approach to a community-based model. Inherent in community-based risk assessment is consideration of the totality of stressors affecting a defined population including both ...

  6. Species of conservation concern and environmental stressors: Local, regional and global effects [Chapter 6] (Executive Summary)

    Science.gov (United States)

    Steven M. Ostoja; Matthew L. Brooks; Jeanne C. Chambers; Burton K. Pendleton

    2013-01-01

    Southern Nevada’s unique landscapes and landforms provide habitat for a diversity of plant and wildlife species of conservation concern including many locally and regionally endemic species. The high population density and urbanization of the Las Vegas metropolitan area is the source of many local and regional stressors that affect these species and their habitats:...

  7. Assessing vulnerability to climate change and socioeconomic stressors in the Reef Islands group, Solomon Islands

    DEFF Research Database (Denmark)

    Birk, Thomas

    2014-01-01

    aims at critically re-assessing this view by placing climate in the context of a range of other internal and external stressors affecting local livelihoods, including population growth, inadequate land use practices, and lack of economic potential, as well as external factors such as poorly developed...

  8. Forecasting the relative influence of environmental and anthropogenic stressors on polar bears

    Science.gov (United States)

    Todd C. Atwood; Bruce G. Marcot; David C. Douglas; Steven C. Amstrup; Karyn D. Rode; George M. Durner; Jeffrey F. Bromaghin

    2016-01-01

    Effective conservation planning requires understanding and ranking threats to wildlife populations. We developed a Bayesian network model to evaluate the relative influence of environmental and anthropogenic stressors, and their mitigation, on the persistence of polar bears (Ursus maritimus). Overall sea ice conditions, affected by rising global...

  9. Characterizing the Life Stressors of Children of Alcoholic Parents

    OpenAIRE

    Hussong, Andrea M.; Bauer, Daniel J.; Huang, Wenjing; Chassin, Laurie; Sher, Kenneth J.; Zucker, Robert A.

    2008-01-01

    The current study examined differences between children of alcoholic (COAs) and non-alcoholic parents in their experience of negative life events across three, longitudinal studies together spanning the first three decades of life. We posited that COAs would differ from their peers in the life domains in which they are vulnerable to stressors, in the recurrence of stressors, and in the severity of stressors. Scale- and item-level analyses of adjusted odds-ratios based on stressors across seve...

  10. Maintaining and restoring sustainable ecosystems in southern Nevada [Chapter 7] (Executive Summary)

    Science.gov (United States)

    Jeanne C. Chambers; Burton K. Pendleton; Donald W. Sada; Steven M. Ostoja; Matthew L.. Brooks

    2013-01-01

    Resource managers in southern Nevada are faced with the challenge of determining appropriate goals and objectives and developing viable approaches for maintaining and restoring sustainable ecosystems in the face of rapid socio-ecological and environmental change. Many of southern Nevada’s ecosystems are being subjected to anthropogenic stressors that span global,...

  11. Job Stressors, Organizational Innovation Climate, and Employees' Innovative Behavior

    Science.gov (United States)

    Ren, Feifei; Zhang, Jinghuan

    2015-01-01

    This study attempted to examine the influence of job stressors and organizational innovation climate on employees' innovative behavior. Data were obtained from 282 employees in 4 cities of China. Results indicated that the nature of stressors matters in predicting employees' idea generation. Specifically, stressors that employees tend to appraise…

  12. Strategic ecosystems of Colombia

    International Nuclear Information System (INIS)

    Marquez Calle German

    2002-01-01

    The author relates the ecosystems in Colombia, he makes a relationship between ecosystems and population, utility of the ecosystems, transformation of the ecosystems and poverty and he shows a methodology of identification of strategic ecosystems

  13. Paraquat and psychological stressor interactions as pertains to Parkinsonian co-morbidity

    Directory of Open Access Journals (Sweden)

    Chris Rudyk

    2015-01-01

    Full Text Available A number of epidemiological and experimental studies have implicated the non-selective herbicide, paraquat, in the development of sporadic Parkinson's disease (PD. While preclinical research has focused mainly on elucidating the nigrostriatal effects of paraquat, relatively little data are available concerning non-motor brain systems and inflammatory immune processes (which have been implicated in PD. Hence, in the present study, we sought to take a multi-system approach to characterize the influence of paraquat upon extra-nigrostriatal brain regions, as well ascertain whether the impact of the pesticide might be enhanced in the context of chronic intermittent stressor exposure. Our findings support the contention that paraquat itself acted as a systemic stressor, with the pesticide increasing plasma corticosterone, as well as altering neurochemical activity in the locus coeruleus, paraventricular nucleus of the hypothalamus, nucleus accumbens, dorsal striatum, and central amygdala. However, with the important exception striatal dopamine turnover, the stressor treatment did not further augment these effects. Additionally, paraquat altered inter-cytokine correlations and, to a lesser extent, circulating cytokine levels, and concomitant stress exposure modulated some of these effects. Finally, paraquat provoked significant (albeit modest reductions of sucrose preference and weight gain, hinting at possible anhendonic-like or sickness responses. These data suggest that, in addition to being a well known oxidative stress generator, paraquat can act as a systemic stressor affecting hormonal and neurochemical activity, but largely not interacting with a concomitant stressor regimen.

  14. Sensory mediation of memory blocking stressors in the pond snail Lymnaea stagnalis.

    Science.gov (United States)

    Dalesman, Sarah; Karnik, Vikram; Lukowiak, Ken

    2011-08-01

    The great pond snail, Lymnaea stagnalis, is commonly used as a model species to study how stress affects the ability to form long-term memory (LTM); however, we still have little information about how the snail senses stressful stimuli. The osphradium is an external sensory organ that demonstrates electrophysiological responses to a variety of external chemical stimuli. We examined the role, if any, played by the osphradium in sensing two environmental stressors, crowding and low environmental calcium, both known to block LTM in intact animals. We severed the osphradial nerve, blocking external sensory input from this organ to the central nervous system, and then exposed the snails to low environmental calcium or crowding stress to assess whether these stressors continued to block LTM formation. When exposed to low environmental calcium, snails with their osphradial nerve severed responded as if they were maintained in our standard calcium environment. That is, they did not respond to low calcium as a stressor blocking LTM; therefore, the osphradium plays a crucial role in mediating how snails respond to this stressor. However, following crowding, LTM formation was blocked in both control groups and snails that had the osphradial nerve severed, indicating that sensory information from the osphradium is not required to sense crowded conditions. Together these data show that two stressors that result in the same behavioural phenotype, blocking LTM formation, do so via two distinct sensory pathways.

  15. High psychosis liability is associated with altered autonomic balance during exposure to Virtual Reality social stressors.

    Science.gov (United States)

    Counotte, Jacqueline; Pot-Kolder, Roos; van Roon, Arie M; Hoskam, Olivier; van der Gaag, Mark; Veling, Wim

    2017-06-01

    Social stressors are associated with an increased risk of psychosis. Stress sensitisation is thought to be an underlying mechanism and may be reflected in an altered autonomic stress response. Using an experimental Virtual Reality design, the autonomic stress response to social stressors was examined in participants with different liability to psychosis. Fifty-five patients with recent onset psychotic disorder, 20 patients at ultra-high risk for psychosis, 42 siblings of patients with psychosis and 53 controls were exposed to social stressors (crowdedness, ethnic minority status and hostility) in a Virtual Reality environment. Heart rate variability parameters and skin conductance levels were measured at baseline and during Virtual Reality experiments. High psychosis liability groups had significantly increased heart rate and decreased heart rate variability compared to low liability groups both at baseline and during Virtual Reality experiments. Both low frequency (LF) and high frequency (HF) power were reduced, while the LF/HF ratio was similar between groups. The number of virtual social stressors significantly affected heart rate, HF, LF/HF and skin conductance level. There was no interaction between psychosis liability and amount of virtual social stress. High liability to psychosis is associated with decreased parasympathetic activity in virtual social environments, which reflects generally high levels of arousal, rather than increased autonomic reactivity to social stressors. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. The Relationship of Stressors and Stress on Injury Incident of Construction Workers in Penang

    Directory of Open Access Journals (Sweden)

    Muhd Ali Khairul Ammar

    2016-01-01

    Full Text Available Construction Workers (CWs are the main source of manpower that is necessary to every construction project. Non conducive and hazardous working environment at construction site will affect the physiological health of the construction labour. This study is conducted to explore the impact of job stress and emotional stress to the CWs that potentially lead to injuries incident in Penang. Twelve stressors were identified through factor analysis. Then, the stressors are classified into five main categories. Questionnaires were developed according to the stressstressor relationship. The correlation between factors of injury incident (stressor and stress shows that lack of autonomy and inappropriate safety equipment lead to the emotional stress among the CWs with 0.287 and 0.204 respectively. In addition, poor physical environment causes the job stress among CWs with the correlation of 0.270.

  17. Working group 7: Ecosystems

    International Nuclear Information System (INIS)

    Verheyen, R.

    1976-01-01

    The purpose of this article is to evaluate the environmental impact of nuclear power plants. The effects of ionizing radiations, of the thermal and chemical pollution on aquatic ecosystems as well as on terrestrial ecosystems have been estimated. After a general survey of such effects and their interaction, practical conclusions in regard to determined areas such as Meuse-Escaut marine and the coast have been drawn. The contamination effects of food chains have been evaluted under deliberately pessimistic conditions with regard to the choice of the radionuclide as well as of concentration factors. Following the biodegradation conditions of the surface waters, criteria for the quality of the aquatic ecosystems have been established. Finally, attention has been paid on certain factors affecting the site selection especially within the frame of the nature conservation. The effects of cooling towers have been also considered. (G.C.)

  18. Ecosystem services as a common language for coastal ecosystem-based management.

    Science.gov (United States)

    Granek, Elise F; Polasky, Stephen; Kappel, Carrie V; Reed, Denise J; Stoms, David M; Koch, Evamaria W; Kennedy, Chris J; Cramer, Lori A; Hacker, Sally D; Barbier, Edward B; Aswani, Shankar; Ruckelshaus, Mary; Perillo, Gerardo M E; Silliman, Brian R; Muthiga, Nyawira; Bael, David; Wolanski, Eric

    2010-02-01

    Ecosystem-based management is logistically and politically challenging because ecosystems are inherently complex and management decisions affect a multitude of groups. Coastal ecosystems, which lie at the interface between marine and terrestrial ecosystems and provide an array of ecosystem services to different groups, aptly illustrate these challenges. Successful ecosystem-based management of coastal ecosystems requires incorporating scientific information and the knowledge and views of interested parties into the decision-making process. Estimating the provision of ecosystem services under alternative management schemes offers a systematic way to incorporate biogeophysical and socioeconomic information and the views of individuals and groups in the policy and management process. Employing ecosystem services as a common language to improve the process of ecosystem-based management presents both benefits and difficulties. Benefits include a transparent method for assessing trade-offs associated with management alternatives, a common set of facts and common currency on which to base negotiations, and improved communication among groups with competing interests or differing worldviews. Yet challenges to this approach remain, including predicting how human interventions will affect ecosystems, how such changes will affect the provision of ecosystem services, and how changes in service provision will affect the welfare of different groups in society. In a case study from Puget Sound, Washington, we illustrate the potential of applying ecosystem services as a common language for ecosystem-based management.

  19. Hotel housekeeping occupational stressors in Norway

    OpenAIRE

    Yap, Matthew H. T.

    2011-01-01

    Stress is evident in the Norwegian hotel industry and requires urgent attention as portrayed in Annbjørg’s housekeeping managerial occupation. Annbjørg’s occupational stressors derived from weak control of and support for demanding jobs in the housekeeping department and possibly under-reward in comparison to her tireless efforts. Hence, this case study provides a platform for educators, trainers, managers, students and learners to critically examine, discuss and argue managerial occupational...

  20. Distal Stressors and Depression among Homeless Men

    OpenAIRE

    Coohey, Carol; Easton, Scott D.

    2016-01-01

    Depression is a common problem among homeless men that may interfere with functional tasks, such as securing stable housing, obtaining employment, and accessing health services. Previous research on depression among homeless men has largely focused on current psychosocial resources, substance abuse, and past victimization. Guided by Ensel and Lin’s life course stress process model, the authors examined whether distal stressors, including victimization and exposure to parent problems in childh...

  1. Cation interdependency in acute stressor states.

    Science.gov (United States)

    Khan, M Usman; Komolafe, Babatunde O; Weber, Karl T

    2013-05-01

    Acute stressor states are inextricably linked to neurohormonal activation which includes the adrenergic nervous system. Consequent elevations in circulating epinephrine and norepinephrine unmask an interdependency that exists between K+, Mg2+ and Ca2+. Catecholamines, for example, regulate the large number of Mg2+-dependent Na/K ATPase pumps present in skeletal muscle. A hyperadrenergic state accounts for a sudden translocation of K+ into muscle and rapid appearance of hypokalemia. In the myocardium, catecholamines promote Mg2+ efflux from cardiomyocytes, whereas intracellular Ca2+ influx and overloading account for the induction of oxidative stress and necrosis of these cells with leakage of their contents, including troponins. Accordingly, acute stressor states can be accompanied by nonischemic elevations in serum troponins, together with the concordant appearance of hypokalemia, hypomagnesemia and ionized hypocalcemia, causing a delay in myocardial repolarization and electrocardiographic QTc prolongation raising the propensity for arrhythmias, including atrial fibrillation and polymorphic ventricular tachycardia. In this review, we focus on the interdependency between K+, Mg2+ and Ca2+ which are clinically relevant to acute stressor states.

  2. Distal Stressors and Depression among Homeless Men.

    Science.gov (United States)

    Coohey, Carol; Easton, Scott D

    2016-05-01

    Depression is a common problem among homeless men that may interfere with functional tasks, such as securing stable housing, obtaining employment, and accessing health services. Previous research on depression among homeless men has largely focused on current psychosocial resources, substance abuse, and past victimization. Guided by Ensel and Lin's life course stress process model, the authors examined whether distal stressors, including victimization and exposure to parent problems in childhood, contributed to men's depression above and beyond current (or proximal) stressors, such as substance abuse and health problems, and social resources. The sample consisted of 309 homeless men who had entered a federally funded emergency shelter. Using the Burns Depression Checklist, the authors found that one out of three men met the threshold for moderate to severe depression during the past week. The logistic regression showed that past exposure to parent problems was related to depression after accounting for current stressors and social resources (number of close adult relationships and whether their emotional support needs were met). Past victimization was not related to depression. To address men's depression, workers should concurrently provide services that meet men's basic needs (for example, housing) and address their relationship needs, including their need for emotional support.

  3. Stressor controllability modulates fear extinction in humans

    Science.gov (United States)

    Hartley, Catherine A.; Gorun, Alyson; Reddan, Marianne C.; Ramirez, Franchesca; Phelps, Elizabeth A.

    2014-01-01

    Traumatic events are proposed to play a role in the development of anxiety disorders, however not all individuals exposed to extreme stress experience a pathological increase in fear. Recent studies in animal models suggest that the degree to which one is able to control an aversive experience is a critical factor determining its behavioral consequences. In this study, we examined whether stressor controllability modulates subsequent conditioned fear expression in humans. Participants were randomly assigned to an escapable stressor condition, a yoked inescapable stressor condition, or a control condition involving no stress exposure. One week later, all participants underwent fear conditioning, fear extinction, and a test of extinction retrieval the following day. Participants exposed to inescapable stress showed impaired fear extinction learning and increased fear expression the following day. In contrast, escapable stress improved fear extinction and prevented the spontaneous recovery of fear. Consistent with the bidirectional controllability effects previously reported in animal models, these results suggest that one's degree of control over aversive experiences may be an important factor influencing the development of psychological resilience or vulnerability in humans. PMID:24333646

  4. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne

    2017-09-14

    Sedimentation, nutrients and metal loading to coastal environments are increasing, associated with urbanization and global warming, hence there is a growing need to predict ecological responses to such change. Using a regression technique we predicted how maximum abundance of 20 macrobenthic taxa and 22 functional traits separately and interactively responded to these key stressors. The abundance of most taxa declined in response to sedimentation and metal loading while a unimodal response was often associated with nutrient loading. Optimum abundances for both taxa and traits occurred at relatively low stressor levels, highlighting the vulnerability of estuaries to increasing stressor loads. Individual taxa were more susceptible to stress than traits, suggesting that functional traits may be less sensitive for detecting changes in ecosystem health. Multiplicative effects were more common than additive interactions. The observed sensitivity of most taxa to increasing sedimentation and metal loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  5. The effects of working conditions and financial state as job stressors : A comparison of the chronic job stressors and job event stressors of two companies

    OpenAIRE

    Kosugi, Shoutaro; Otsuka, Yasumasa

    2000-01-01

    This study examined the effects of working conditions and the financial state as chronic job stressors and job event stressors. In study 1, the Job Stress Scale was applied to a total of 6,312 employees in an industrial research institute and a construction company to measure chronic job stressors. In study 2, 1,423 employees of these companies filled out the Job Events Checklist to measure job event stressors. Result: Employees in the industrial research institute had more chronic job stress...

  6. Major impacts of climate change on deep-sea benthic ecosystems

    Directory of Open Access Journals (Sweden)

    Andrew K. Sweetman

    2017-02-01

    Full Text Available The deep sea encompasses the largest ecosystems on Earth. Although poorly known, deep seafloor ecosystems provide services that are vitally important to the entire ocean and biosphere. Rising atmospheric greenhouse gases are bringing about significant changes in the environmental properties of the ocean realm in terms of water column oxygenation, temperature, pH and food supply, with concomitant impacts on deep-sea ecosystems. Projections suggest that abyssal (3000–6000 m ocean temperatures could increase by 1°C over the next 84 years, while abyssal seafloor habitats under areas of deep-water formation may experience reductions in water column oxygen concentrations by as much as 0.03 mL L–1 by 2100. Bathyal depths (200–3000 m worldwide will undergo the most significant reductions in pH in all oceans by the year 2100 (0.29 to 0.37 pH units. O2 concentrations will also decline in the bathyal NE Pacific and Southern Oceans, with losses up to 3.7% or more, especially at intermediate depths. Another important environmental parameter, the flux of particulate organic matter to the seafloor, is likely to decline significantly in most oceans, most notably in the abyssal and bathyal Indian Ocean where it is predicted to decrease by 40–55% by the end of the century. Unfortunately, how these major changes will affect deep-seafloor ecosystems is, in some cases, very poorly understood. In this paper, we provide a detailed overview of the impacts of these changing environmental parameters on deep-seafloor ecosystems that will most likely be seen by 2100 in continental margin, abyssal and polar settings. We also consider how these changes may combine with other anthropogenic stressors (e.g., fishing, mineral mining, oil and gas extraction to further impact deep-seafloor ecosystems and discuss the possible societal implications.

  7. Designer ecosystems

    NARCIS (Netherlands)

    Awasthi, Ashutosh; Singh, Kripal; O'Grady, Audrey; Courtney, Ronan; Kalra, Alok; Singh, Rana Pratap; Cerda Bolinches, Artemio; Steinberger, Yosef; Patra, D.D.

    2016-01-01

    Increase in human population is accelerating the rate of land use change, biodiversity loss and habitat degradation, triggering a serious threat to life supporting ecosystem services. Existing strategies for biological conservation remain insufficient to achieve a sustainable human-nature

  8. Modelling coral reef futures to inform management: can reducing local-scale stressors conserve reefs under climate change?

    Science.gov (United States)

    Gurney, Georgina G; Melbourne-Thomas, Jessica; Geronimo, Rollan C; Aliño, Perry M; Johnson, Craig R

    2013-01-01

    Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef

  9. Modelling coral reef futures to inform management: can reducing local-scale stressors conserve reefs under climate change?

    Directory of Open Access Journals (Sweden)

    Georgina G Gurney

    Full Text Available Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general

  10. Modelling Coral Reef Futures to Inform Management: Can Reducing Local-Scale Stressors Conserve Reefs under Climate Change?

    Science.gov (United States)

    Gurney, Georgina G.; Melbourne-Thomas, Jessica; Geronimo, Rollan C.; Aliño, Perry M.; Johnson, Craig R.

    2013-01-01

    Climate change has emerged as a principal threat to coral reefs, and is expected to exacerbate coral reef degradation caused by more localised stressors. Management of local stressors is widely advocated to bolster coral reef resilience, but the extent to which management of local stressors might affect future trajectories of reef state remains unclear. This is in part because of limited understanding of the cumulative impact of multiple stressors. Models are ideal tools to aid understanding of future reef state under alternative management and climatic scenarios, but to date few have been sufficiently developed to be useful as decision support tools for local management of coral reefs subject to multiple stressors. We used a simulation model of coral reefs to investigate the extent to which the management of local stressors (namely poor water quality and fishing) might influence future reef state under varying climatic scenarios relating to coral bleaching. We parameterised the model for Bolinao, the Philippines, and explored how simulation modelling can be used to provide decision support for local management. We found that management of water quality, and to a lesser extent fishing, can have a significant impact on future reef state, including coral recovery following bleaching-induced mortality. The stressors we examined interacted antagonistically to affect reef state, highlighting the importance of considering the combined impact of multiple stressors rather than considering them individually. Further, by providing explicit guidance for management of Bolinao's reef system, such as which course of management action will most likely to be effective over what time scales and at which sites, we demonstrated the utility of simulation models for supporting management. Aside from providing explicit guidance for management of Bolinao's reef system, our study offers insights which could inform reef management more broadly, as well as general understanding of reef

  11. Changes in food web structure and ecosystem functioning of a large, shallow Chinese lake during the 1950s, 1980s and 2000s

    NARCIS (Netherlands)

    Kong, Xiangzhen; He, Wei; Liu, Wenxiu; Yang, Bin; Xu, Fuliu; Jørgensen, Sven Erik; Mooij, W.M.

    2016-01-01

    Food web structure dynamics and ecosystem functioning are strongly linked, and both are indispensable in evaluating ecosystem development in lakes under multiple anthropogenic stressors. However, model-based approaches concerning the changes in food web structure and ecosystem functioning in a

  12. Coastal Forests and Groundwater: Using Case Studies to Understand the Effects of Drivers and Stressors for Resource Management

    Directory of Open Access Journals (Sweden)

    Timothy J. Callahan

    2017-03-01

    Full Text Available Forests are receiving more attention for the ecosystem goods and services they provide and the potential change agents that may affect forest health and productivity. Highlighting case examples from coastal forests in South Carolina, USA, we describe groundwater processes with respect to stressors and potential responses of a wetland-rich forested landscape, the roles that this area has served, and the need for water resource data to inform forest management decisions. Forested lands in the southeastern U.S. coastal plain provide a rich set of goods and services for the region, and in one case, the Francis Marion National Forest acts as a buffer to urbanization from the surrounding Charleston metropolitan area. Information from two decades of studies in the forested watersheds there may inform scientists and managers in other coastal forested systems. The common hydrological theme in this region, which has a higher average annual rainfall (1370 mm than the annual potential evapotranspiration (PET = 1135 mm, is a shallow (<3 m water table condition that supports a large range of natural wetlands and also creates management challenges across the region. Modest changes in the position of the water table can lead to either groundwater flooding and concomitant management challenges for forest services, or ecosystem stresses related to dry conditions in wetlands during times of below-normal precipitation or due to groundwater withdrawal. Development pressures have also stressed forest resources through the extraction of materials such as timber and sand mining, and the conversion to housing construction materials. These areas are also targeted for land development, to meet housing demands. In this paper, we discuss the role of groundwater in coastal forests and highlight opportunities for collaborative studies to better inform forest resource management.

  13. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    OpenAIRE

    Alele, Peter O; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these diffe...

  14. The Relationship Between Stressors and Anxiety Levels After CABG in Sari, Iran.

    Science.gov (United States)

    Bagheri Nesami, Masoumeh; Shorofi, Seyed Afshin; Jafari, Azam; Khalilian, Ali Reza; Ziabakhsh Tabari, Shervin

    2016-05-01

    Hospitalization and surgery are crucial adverse life events that lead to considerable anxiety in patients. The present study aimed to investigate stressors after coronary artery bypass graft surgery and identify stressors that predict anxiety. This is a descriptive-analytical study that uses a non-random convenience sampling method on patients undergoing coronary artery bypass graft surgery at the cardiac surgery intensive care unit of Fatemeh Zahra Cardiac center in Sari, Iran. A total of 186 patients completed the post-surgical stressors questionnaire and the Spielberger State-Trait Anxiety Inventory on postoperative days 2 or 3 in the cardiac surgery intensive care unit. Data were analyzed using descriptive statistics including frequencies, means, and standard deviations. The Mann-Whitney U test was used to determine the relationship between the observed variables, and the logistic regression model was used to identify the relationship between stressors and anxiety after-surgery. Post-surgical anxiety predictors included insufficient sleep during hospitalization (Odds ratio [OR]: 5.42; 95% confidence interval [CI]: 1.46 - 20.00; P = 0.010), treatment not explained to the patient by the nurse (OR: 4.83; 95% CI: 1.82 - 12.84; P = 0.002), being away from family members (OR: 3.88; 95% CI: 1.46 - 10.26; P = 0.006), presence of a chest tube (OR: 3.27; 95% CI: 1.83 - 5.84; P = 0.000), and pain in any part of the body (OR: 1.95; 95% CI: 1.06 - 3.58; P = 0.031). Physical or physiological and psychological stressors impose greater stress and are predictors of anxiety. When preparing their nursing care plan, nurses should consider these stressors that affect anxiety levels in patients undergoing CABG surgery and those hospitalized in intensive care units.

  15. Developing a multi-stressor gradient for coral reefs | Science ...

    Science.gov (United States)

    Coral reefs are often found near coastal waters where multiple anthropogenic stressors co-occur at areas of human disturbance. Developing coral reef biocriteria under the U.S. Clean Water Act requires relationships between anthropogenic stressors and coral reef condition to be established. Developing stressor gradients presents challenges including: stressors which co-occur but operate at different or unknown spatial and temporal scales, inconsistent data availability measuring stressor levels, and unknown effects on exposed reef biota. We are developing a generalized stressor model using Puerto Rico as case study location, to represent the cumulative spatial/temporal co-occurrence of multiple anthropogenic stressors. Our approach builds on multi-stressor research in streams and rivers, and focuses on three high-priority stressors identified by coral reef experts: land-based sources of pollution (LBSP), global climate change (GCC) related temperature anomalies, and fishing pressure. Landscape development intensity index, based on land use/land cover data, estimates human impact in watersheds adjacent to coral reefs and is proxy for LBSP. NOAA’s retrospective daily thermal anomaly data is used to determine GCC thermal anomalies. Fishing pressure is modeled using gear-specific and fishery landings data. Stressor data was adjusted to a common scale or weighted for relative importance, buffered to account for diminished impact further from source, and compared wit

  16. Mechanisms and risk of cumulative impacts to coastal ecosystem services: An expert elicitation approach

    KAUST Repository

    Singh, Gerald G.

    2017-05-23

    Coastal environments are some of the most populated on Earth, with greater pressures projected in the future. Managing coastal systems requires the consideration of multiple uses, which both benefit from and threaten multiple ecosystem services. Thus understanding the cumulative impacts of human activities on coastal ecosystem services would seem fundamental to management, yet there is no widely accepted approach for assessing these. This study trials an approach for understanding the cumulative impacts of anthropogenic change, focusing on Tasman and Golden Bays, New Zealand. Using an expert elicitation procedure, we collected information on three aspects of cumulative impacts: the importance and magnitude of impacts by various activities and stressors on ecosystem services, and the causal processes of impact on ecosystem services. We assessed impacts to four ecosystem service benefits — fisheries, shellfish aquaculture, marine recreation and existence value of biodiversity—addressing three main research questions: (1) how severe are cumulative impacts on ecosystem services (correspondingly, what potential is there for restoration)?; (2) are threats evenly distributed across activities and stressors, or do a few threats dominate?; (3) do prominent activities mainly operate through direct stressors, or do they often exacerbate other impacts? We found (1) that despite high uncertainty in the threat posed by individual stressors and impacts, total cumulative impact is consistently severe for all four ecosystem services. (2) A subset of drivers and stressors pose important threats across the ecosystem services explored, including climate change, commercial fishing, sedimentation and pollution. (3) Climate change and commercial fishing contribute to prominent indirect impacts across ecosystem services by exacerbating regional impacts, namely sedimentation and pollution. The prevalence and magnitude of these indirect, networked impacts highlights the need for

  17. Mechanisms and risk of cumulative impacts to coastal ecosystem services: An expert elicitation approach.

    Science.gov (United States)

    Singh, Gerald G; Sinner, Jim; Ellis, Joanne; Kandlikar, Milind; Halpern, Benjamin S; Satterfield, Terre; Chan, Kai M A

    2017-09-01

    Coastal environments are some of the most populated on Earth, with greater pressures projected in the future. Managing coastal systems requires the consideration of multiple uses, which both benefit from and threaten multiple ecosystem services. Thus understanding the cumulative impacts of human activities on coastal ecosystem services would seem fundamental to management, yet there is no widely accepted approach for assessing these. This study trials an approach for understanding the cumulative impacts of anthropogenic change, focusing on Tasman and Golden Bays, New Zealand. Using an expert elicitation procedure, we collected information on three aspects of cumulative impacts: the importance and magnitude of impacts by various activities and stressors on ecosystem services, and the causal processes of impact on ecosystem services. We assessed impacts to four ecosystem service benefits - fisheries, shellfish aquaculture, marine recreation and existence value of biodiversity-addressing three main research questions: (1) how severe are cumulative impacts on ecosystem services (correspondingly, what potential is there for restoration)?; (2) are threats evenly distributed across activities and stressors, or do a few threats dominate?; (3) do prominent activities mainly operate through direct stressors, or do they often exacerbate other impacts? We found (1) that despite high uncertainty in the threat posed by individual stressors and impacts, total cumulative impact is consistently severe for all four ecosystem services. (2) A subset of drivers and stressors pose important threats across the ecosystem services explored, including climate change, commercial fishing, sedimentation and pollution. (3) Climate change and commercial fishing contribute to prominent indirect impacts across ecosystem services by exacerbating regional impacts, namely sedimentation and pollution. The prevalence and magnitude of these indirect, networked impacts highlights the need for approaches

  18. Language as a Stressor in Aphasia

    Science.gov (United States)

    Cahana-Amitay, Dalia; Albert, Martin L.; Pyun, Sung-Bom; Westwood, Andrew; Jenkins, Theodore; Wolford, Sarah; Finley, Mallory

    2012-01-01

    Background Persons with aphasia often report feeling anxious when using language while communicating. While many patients, caregivers, clinicians and researchers would agree that language may be a stressor for persons with aphasia, systematic empirical studies of stress and/or anxiety in aphasia remain scarce. Aim The aim of this paper is to review the existing literature discussing language as a stressor in aphasia, identify key issues, highlight important gaps, and propose a program for future study. In doing so, we hope to underscore the importance of understanding aspects of the emotional aftermath of aphasia, which plays a critical role in the process of recovery and rehabilitation. Main Contribution Post stroke emotional dysregulation in persons with chronic aphasia clearly has adverse effects for language performance and prospects of recovery. However, the specific role anxiety might play in aphasia has yet to be determined. As a starting point, we propose to view language in aphasia as a stressor, linked to an emotional state we term “linguistic anxiety.” Specifically, a person with linguistic anxiety is one in whom the deliberate, effortful production of language involves anticipation of an error, with the imminence of linguistic failure serving as the threat. Since anticipation is psychologically linked to anxiety and also plays an important role in the allostatic system, we suggest that examining physiologic stress responses in persons with aphasia when they are asked to perform a linguistic task would be a productive tool for assessing the potential relation of stress to “linguistic anxiety.” Conclusion Exploring the putative relationship between anxiety and language in aphasia, through the study of physiologic stress responses, could establish a platform for investigating language changes in the brain in other clinical populations, such as in individuals with Alzheimer’s disease or persons with post traumatic stress disorder, or even with

  19. Characteristics of initial deposition and behavior of radiocesium in forest ecosystems of different locations and species affected by the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Komatsu, Masabumi; Kaneko, Shinji; Ohashi, Shinta; Kuroda, Katsushi; Sano, Tetsuya; Ikeda, Shigeto; Saito, Satoshi; Kiyono, Yoshiyuki; Tonosaki, Mario; Miura, Satoru; Akama, Akio; Kajimoto, Takuya; Takahashi, Masamichi

    2016-01-01

    ), the amount of rainfall after the accident, and the leaf biomass by the tree species may influence differences in the spatial pattern of radiocesium by study plots. The results of the present study and further studies of the spatial pattern of radiocesium are important for modeling future radiocesium distribution in contaminated forest ecosystems. - Highlights: • We estimated the amounts of radiocesium in five forests 6 months after the accident. • The proportion of "1"3"7Cs stock in the aboveground biomass varied from 18% to 44%. • The initial spatial pattern of radiocesium is important for future modeling.

  20. The role of recurrent disturbances for ecosystem multifunctionality.

    Science.gov (United States)

    Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf B; Lukkari, Kaarina; Norkko, Alf

    2013-10-01

    Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in response to repetitive pulse disturbances. The degradation in overall ecosystem functioning was, however, evident at an earlier stage than for single ecosystem functions and was induced after a short pulse of hypoxia (i.e., three days), which likely reduced ecosystem resistance to further hypoxic perturbations. The increasing number of repeated pulse disturbances gradually moved the system closer to a press response. In addition to the disturbance regime, the changes in benthic trait composition as well as habitat heterogeneity were important for explaining the variability in overall ecosystem functioning. Our results suggest that disturbance-induced responses across multiple ecosystem functions can serve as a warning signal for losses of the adaptive capacity of an ecosystem, and might at an early stage provide information to managers and policy makers when remediation efforts should be initiated.

  1. Stressors and Stressor Response Levels of Hong Kong Primary School Music Teachers

    Science.gov (United States)

    Wong, Marina Wai-yee; Chik, Maria Pik-yuk; Chan, Edmund Sze Shing

    2018-01-01

    Responses from 309 randomly sampled Hong Kong primary school music teachers to the shortened version of the Chinese Teacher Stress Questionnaire were subjected to a descriptive percentage analysis, one-way ANOVA and independent t test. Obtained results identify five key stressors: "changing education policy of the government";…

  2. Health Behaviors and Overweight in Nursing Home Employees: Contribution of Workplace Stressors and Implications for Worksite Health Promotion.

    Science.gov (United States)

    Miranda, Helena; Gore, Rebecca J; Boyer, Jon; Nobrega, Suzanne; Punnett, Laura

    2015-01-01

    Many worksite health promotion programs ignore the potential influence of working conditions on unhealthy behaviors. A study of nursing home employees (56% nursing aides) utilized a standardized questionnaire. We analyzed the cross-sectional associations between workplace stressors and obesity, cigarette smoking, and physical inactivity. Of 1506 respondents, 20% reported exposure to three or more workplace stressors (physical or organizational), such as lifting heavy loads, low decision latitude, low coworker support, regular night work, and physical assault. For each outcome, the prevalence ratio was between 1.5 and 2 for respondents with four or five job stressors. Individuals under age 40 had stronger associations between workplace stressors and smoking and obesity. Workplace stressors were strongly associated with smoking, obesity, and physical inactivity, even among the lowest-status workers. Current working conditions affected younger workers more than older workers. Although this study is cross-sectional, it has other strengths, including the broad range of work stressors studied. Strenuous physical work and psychosocial strain are common among low-wage workers such as nursing home aides. Workplace health promotion programs may be more effective if they include measures to reduce stressful work environment features, so that working conditions support rather than interfere with employee health.

  3. Work stressors, depressive symptoms and sleep quality among US Navy members: a parallel process latent growth modelling approach across deployment.

    Science.gov (United States)

    Bravo, Adrian J; Kelley, Michelle L; Swinkels, Cindy M; Ulmer, Christi S

    2017-11-03

    The present study examined whether work stressors contribute to sleep problems and depressive symptoms over the course of deployment (i.e. pre-deployment, post-deployment and 6-month reintegration) among US Navy members. Specifically, we examined whether depressive symptoms or sleep quality mediate the relationships between work stressors and these outcomes. Participants were 101 US Navy members who experienced an 8-month deployment after Operational Enduring Freedom/Operation Iraqi Freedom. Using piecewise latent growth models, we found that increased work stressors were linked to increased depressive symptoms and decreased sleep quality across all three deployment stages. Further, increases in work stressors from pre- to post-deployment contributed to poorer sleep quality post-deployment via increasing depressive symptoms. Moreover, sleep quality mediated the association between increases in work stressors and increases in depressive symptoms from pre- to post-deployment. These effects were maintained from post-deployment through the 6-month reintegration. Although preliminary, our results suggest that changes in work stressors may have small, but significant implications for both depressive symptoms and quality of sleep over time, and a bi-directional relationship persists between sleep quality and depression across deployment. Strategies that target both stress and sleep could address both precipitating and perpetuating factors that affect sleep and depressive symptoms. © 2017 European Sleep Research Society.

  4. Effect of Changing Work Stressors and Coping Resources on the Risk of Type 2 Diabetes: The OHSPIW Cohort Study.

    Science.gov (United States)

    Lian, Yulong; Sun, Qing; Guan, Suzhen; Ge, Hua; Tao, Ning; Jiang, Yu; Zhang, YanXia; Ning, Li; Xiao, Jing; Liu, Jiwen

    2018-03-01

    Little is known about the relationship between changing psychosocial work conditions and type 2 diabetes. We determined whether changing work stressors and coping resources affect the risk of type 2 diabetes. In this prospective cohort (2003-2014) of 3,740 workers without diabetes (OHSPIW [Occupational Health Study of Petroleum Industry Workers]), participants completed an evaluation of work-related stress and coping resources and type 2 diabetes diagnosis at baseline and 12 years follow-up (two waves). The changes in work stressors and coping resources were measured with the Occupation Stress Inventory-Revised and the Instrument for Stress-Related Job Analysis (Version 6.0). Type 2 diabetes was diagnosed on the basis of an oral glucose tolerance test supplemented by physician report. Increased task stressors (relative risk [RR] 1.57 [95% CI 1.03-2.63]) and decreased coping resources (RR 1.68 [95% CI 1.02-2.83]) were associated with risk of type 2 diabetes. The main risk factors were increased role overload, increased role insufficiency, increased physical environment stressors, decreased self-care, and decreased rational coping. Increased coping resources also had a buffering effect on increased task stressors and type 2 diabetes. Changes in work stressors and coping resources have an influence on the risk for type 2 diabetes, highlighting the importance of preventive measures against adverse psychosocial work conditions and reduced coping resources for diabetes prevention in the workplace. © 2017 by the American Diabetes Association.

  5. Placing ecosystem sustainability within the context of dynamic earth systems

    Science.gov (United States)

    Sidle, R. C.

    2013-12-01

    Because the concept of ecosystem sustainability and the practice of sustainable land management both have long-term foci, it is necessary to view these from the perspective of dynamic rather than static systems. In addition to the typical static system approach for assessing ecosystem sustainability, three additional perspectives are presented. These are resilient systems, systems where tipping points occur, and systems subject to episodic geophysical resetting. Ecosystem resilience accommodates both natural and anthropogenic stressors and should be considered to properly frame many ecosystem assessments. A more complex problem emerges when stressors push systems to tipping points, causing a regime shift. Both chronic anthropogenic activities (e.g., over-grazing, forest conversion, poor irrigation practices) and natural changes (e.g., climate anomalies, geochemical weathering, tectonic uplift, vegetative succession) can exhaust ecosystem resilience leading to a rapid change in state. Anthropogenic perturbations can also lower the initiation threshold and increase the magnitude and frequency of certain natural disasters, increasing the likelihood of ecosystem change. Furthermore, when major episodic geophysical events (e.g., large earthquakes, tsunami, and floods; widespread volcanic activity and landslides) exceed thresholds of ecosystem resilience they may reset the attributes of entire systems or landscapes. Large disasters can initiate a cascade of linked events, as in the 2011 Great East Japan Earthquake, where tsunami, fires, landslides, artificial fillslope collapses, radioactive releases, and associated health effects occurred. Understanding the potential for natural change (both chronic and episodic) in ecosystems is essential not only to the environmental aspect of sustainability but also to economic and social aspects. Examples are presented for: (1) ecosystems vulnerable to tipping points (Yunnan, China) and (2) ecosystems reset by earthquakes and

  6. The relationship between stressors and burnout in college athletes

    OpenAIRE

    木村, 彩; 手塚, 洋介; 杉山, 佳生; Kimura, Aya; Tezuka, Yosuke; Sugiyama, Yoshio

    2013-01-01

    This study was conducted to examine the relationship between stressors and burnout (in terms of stress response) in college athletes. Participants comprised 233 college athletes (84 males and 149 females; M_ = 20.0 years and SD = 1.2 years) who completed the daily and competitive stressor scale and the Athletic Burnout Inventory. Multiple regression analysis showed that almost all the observed factors of stressors tended to be associated with each burnout factor. It also showed that not only ...

  7. Stressors, Appraisal of Stressors, Experienced Stress and Cardiac Response: A Real-Time, Real-Life Investigation of Work Stress in Nurses.

    Science.gov (United States)

    Johnston, Derek; Bell, Cheryl; Jones, Martyn; Farquharson, Barbara; Allan, Julia; Schofield, Patricia; Ricketts, Ian; Johnston, Marie

    2016-04-01

    Stress in health care professionals may reflect both the work and appraisal of work and impacts on the individuals, their patients, colleagues and managers. The purpose of the present study is to examine physiological and psychological effects of stressors (tasks) and theory-based perceptions of work stressors within and between nurses in real time. During two work shifts, 100 nurses rated experienced stress, affect, fatigue, theory-based measures of work stress and nursing tasks on electronic diaries every 90 min, whereas heart rate and activity were measured continuously. Heart rate was associated with both demand and effort. Experienced stress was related to demand, control, effort and reward. Effort and reward interacted as predicted (but only within people). Results were unchanged when allowance was made for work tasks. Real-time appraisals were more important than actual tasks in predicting both psychological and physiological correlates of stress. At times when effort was high, perceived reward reduced stress.

  8. Stressor states and the cation crossroads.

    Science.gov (United States)

    Weber, Karl T; Bhattacharya, Syamal K; Newman, Kevin P; Soberman, Judith E; Ramanathan, Kodangudi B; McGee, Jesse E; Malik, Kafait U; Hickerson, William L

    2010-12-01

    Neurohormonal activation involving the hypothalamic-pituitary-adrenal axis and adrenergic nervous and renin-angiotensin-aldosterone systems is integral to stressor state-mediated homeostatic responses. The levels of effector hormones, depending upon the degree of stress, orchestrate the concordant appearance of hypokalemia, ionized hypocalcemia and hypomagnesemia, hypozincemia, and hyposelenemia. Seemingly contradictory to homeostatic responses wherein the constancy of extracellular fluid would be preserved, upregulation of cognate-binding proteins promotes coordinated translocation of cations to injured tissues, where they participate in wound healing. Associated catecholamine-mediated intracellular cation shifts regulate the equilibrium between pro-oxidants and antioxidant defenses, a critical determinant of cell survival. These acute and chronic stressor-induced iterations in extracellular and intracellular cations are collectively referred to as the cation crossroads. Intracellular cation shifts, particularly excessive accumulation of Ca2+, converge on mitochondria to induce oxidative stress and raise the opening potential of their inner membrane permeability transition pores (mPTPs). The ensuing loss of cationic homeostasis and adenosine triphosphate (ATP) production, together with osmotic swelling, leads to organellar degeneration and cellular necrosis. The overall impact of iterations in extracellular and intracellular cations and their influence on cardiac redox state, cardiomyocyte survival, and myocardial structure and function are addressed herein.

  9. Job stressors and coping in health professions.

    Science.gov (United States)

    Heim, E

    1991-01-01

    In spite of their knowledge about stressors, health hazards and coping, health professionals are in general not aware of their own health risks. In an attempt to clarify the issue results of our own studies are compared to the relevant literature. A survey on 1,248 Swiss nurses confirmed the major stressors known: ethical conflicts about appropriate patient care, team conflicts, role ambiguity, workload and organizational deficits. In doctors workload and shortage of time, combined with specific responsibility in decision making, are most prominent. Nevertheless, job satisfaction is still high in both professions. Health hazards in doctors are considerable, although life expectancy has improved and is comparable to the general public, but still lower as compared to other professionals. Depression and substance abuse are related to higher suicide rates. The specific role strain of female doctors is responsible for health risks with an alarming 10 years lower life expectancy than in the general population. Little is known about specific health hazards in nurses, except for burnout. A lack of coping research in the field makes conclusions difficult. Our own studies show limited coping skills in nurses, but good buffering effect in 1,700 Swiss dentists.

  10. ENVIRONMENTAL STRESSOR AND EXPOSURE INFORMATION FOR OLDER ADULTS

    Science.gov (United States)

    This product describes results of literature and data reviews to identify important chemical and biological stressors in the aging population, summarize extant exposure information, and identify data gaps.

  11. Using transcriptomic profiles in the diatom Phaeodactylum tricornutum to identify and prioritize stressors

    International Nuclear Information System (INIS)

    Osborn, Hannah L.; Hook, Sharon E.

    2013-01-01

    for each contaminant tested (copper, cadmium, silver, salinity and ammonia) responded exclusively to that contaminant. With further development of additional transcriptomic markers for each contaminant, this new approach has potential to enhance traditional toxicology bioassays by providing additional lines of evidence to identify biologically relevant stressors within a contaminated ecosystem based on changes in the transcriptomic profile

  12. Using transcriptomic profiles in the diatom Phaeodactylum tricornutum to identify and prioritize stressors

    Energy Technology Data Exchange (ETDEWEB)

    Osborn, Hannah L., E-mail: Hannah.Osborn@csiro.au; Hook, Sharon E., E-mail: Sharon.Hook@csiro.au

    2013-08-15

    -based approach. At least one transcript for each contaminant tested (copper, cadmium, silver, salinity and ammonia) responded exclusively to that contaminant. With further development of additional transcriptomic markers for each contaminant, this new approach has potential to enhance traditional toxicology bioassays by providing additional lines of evidence to identify biologically relevant stressors within a contaminated ecosystem based on changes in the transcriptomic profile.

  13. Differential challenge stressor-hindrance stressor relationships with job attitudes, turnover intentions, turnover, and withdrawal behavior: a meta-analysis.

    Science.gov (United States)

    Podsakoff, Nathan P; LePine, Jeffery A; LePine, Marcie A

    2007-03-01

    In this article, a 2-dimensional work stressor framework is used to explain inconsistencies in past research with respect to stressor relationships with retention-related criteria. Results of meta-analyses of 183 independent samples indicated that whereas hindrance stressors had dysfunctional relationships with these criteria (negative relationships with job satisfaction and organizational commitment and positive relationships with turnover intentions, turnover, and withdrawal behavior), relationships with challenge stressors were generally the opposite (positive relationships with job satisfaction and organizational commitment and negative relationships with turnover intentions and turnover). Results also suggested that the differential relationships between challenge stressors and hindrance stressors and the more distal criteria (withdrawal behavior and turnover) were due, in part, to the mediating effects of job attitudes. (c) 2007 APA, all rights reserved.

  14. Beliefs in an Unjust World: Mediating Ethnicity-Related Stressors and Psychological Functioning.

    Science.gov (United States)

    Liang, Christopher T H; Molenaar, Carin M

    2016-06-01

    Racism is negatively associated with health. Explorations of cognitive reactions, such as beliefs in an unjust world (BUW), are needed to understand the associations between both perceived discrimination and own-group conformity pressures (OGCPS) and reduced psychological well-being. With a sample of 215 ethnic minority individuals, this study used structural equation modeling to explore BUW's mediating role between the two aforementioned forms of ethnicity-related stressors (ERS), anger rumination, and negative affect. ERS were directly positively associated with BUW, anger rumination, and negative affect. BUW were directly and positively associated with both anger rumination and negative affect. Finally, BUW significantly mediated the direct relationships between both ethnicity-related stressors and anger rumination and negative affect. Although addressing racism and OGCPS at a systemic level (e.g., policy, prejudice prevention) is needed to reduce ERS, these findings suggest that BUW is one point of possible clinical intervention for individuals who have experienced these stressors. © 2016 Wiley Periodicals, Inc.

  15. Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks

    Science.gov (United States)

    Hooper, Michael J.; Ankley, Gerald T.; Cristol, Daniel A.; Maryoung, Lindley A.; Noyes, Pamela D.; Pinkerton, Kent E.

    2013-01-01

    Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical–GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical–climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments.

  16. Are work-related stressors associated with diagnosis of more advanced stages of incident breast cancers?

    DEFF Research Database (Denmark)

    Nielsen, Naja Rod; Stahlberg, Claudia; Strandberg-Larsen, Katrine

    2008-01-01

    work pressure (HR = 1.17; 95% CI: 0.79, 1.73) nor women with self-reported low influence on work organization (0.98; 0.69, 1.39) or long working hours (0.93; 0.54, 1.58) were at higher risk of breast cancer than women with no such stressors. Women with high work tempo had a slightly higher risk......OBJECTIVE: To assess the relation between work-related stressors and breast cancer incidence and prognostic characteristics (estrogen receptor status, grade, lymph node status, size, stage) at the time of diagnosis. METHODS: The 18,932 women included in the Danish Nurse Cohort reported work...... of breast cancer (1.25; 1.02, 1.54) than women with a suitable work tempo, but there was no dose-response effect. There were no clear differences in the prognostic characteristics of breast tumors diagnosed in women with and without work-related stressors. CONCLUSIONS: Work-related stressors do not affect...

  17. A model ecosystem experiment and its computational simulation studies

    International Nuclear Information System (INIS)

    Doi, M.

    2002-01-01

    Simplified microbial model ecosystem and its computer simulation model are introduced as eco-toxicity test for the assessment of environmental responses from the effects of environmental impacts. To take the effects on the interactions between species and environment into account, one option is to select the keystone species on the basis of ecological knowledge, and to put it in the single-species toxicity test. Another option proposed is to put the eco-toxicity tests as experimental micro ecosystem study and a theoretical model ecosystem analysis. With these tests, the stressors which are more harmful to the ecosystems should be replace with less harmful ones on the basis of unified measures. Management of radioactive materials, chemicals, hyper-eutrophic, and other artificial disturbances of ecosystem should be discussed consistently from the unified view point of environmental protection. (N.C.)

  18. The Micronesia Challenge: Assessing the Relative Contribution of Stressors on Coral Reefs to Facilitate Science-to-Management Feedback.

    Science.gov (United States)

    Houk, Peter; Camacho, Rodney; Johnson, Steven; McLean, Matthew; Maxin, Selino; Anson, Jorg; Joseph, Eugene; Nedlic, Osamu; Luckymis, Marston; Adams, Katrina; Hess, Don; Kabua, Emma; Yalon, Anthony; Buthung, Eva; Graham, Curtis; Leberer, Trina; Taylor, Brett; van Woesik, Robert

    2015-01-01

    Fishing and pollution are chronic stressors that can prolong recovery of coral reefs and contribute to ecosystem decline. While this premise is generally accepted, management interventions are complicated because the contributions from individual stressors are difficult to distinguish. The present study examined the extent to which fishing pressure and pollution predicted progress towards the Micronesia Challenge, an international conservation strategy initiated by the political leaders of 6 nations to conserve at least 30% of marine resources by 2020. The analyses were rooted in a defined measure of coral-reef-ecosystem condition, comprised of biological metrics that described functional processes on coral reefs. We report that only 42% of the major reef habitats exceeded the ecosystem-condition threshold established by the Micronesia Challenge. Fishing pressure acting alone on outer reefs, or in combination with pollution in some lagoons, best predicted both the decline and variance in ecosystem condition. High variances among ecosystem-condition scores reflected the large gaps between the best and worst reefs, and suggested that the current scores were unlikely to remain stable through time because of low redundancy. Accounting for the presence of marine protected area (MPA) networks in statistical models did little to improve the models' predictive capabilities, suggesting limited efficacy of MPAs when grouped together across the region. Yet, localized benefits of MPAs existed and are expected to increase over time. Sensitivity analyses suggested that (i) grazing by large herbivores, (ii) high functional diversity of herbivores, and (iii) high predator biomass were most sensitive to fishing pressure, and were required for high ecosystem-condition scores. Linking comprehensive fisheries management policies with these sensitive metrics, and targeting the management of pollution, will strengthen the Micronesia Challenge and preserve ecosystem services that coral

  19. The Micronesia Challenge: Assessing the Relative Contribution of Stressors on Coral Reefs to Facilitate Science-to-Management Feedback.

    Directory of Open Access Journals (Sweden)

    Peter Houk

    Full Text Available Fishing and pollution are chronic stressors that can prolong recovery of coral reefs and contribute to ecosystem decline. While this premise is generally accepted, management interventions are complicated because the contributions from individual stressors are difficult to distinguish. The present study examined the extent to which fishing pressure and pollution predicted progress towards the Micronesia Challenge, an international conservation strategy initiated by the political leaders of 6 nations to conserve at least 30% of marine resources by 2020. The analyses were rooted in a defined measure of coral-reef-ecosystem condition, comprised of biological metrics that described functional processes on coral reefs. We report that only 42% of the major reef habitats exceeded the ecosystem-condition threshold established by the Micronesia Challenge. Fishing pressure acting alone on outer reefs, or in combination with pollution in some lagoons, best predicted both the decline and variance in ecosystem condition. High variances among ecosystem-condition scores reflected the large gaps between the best and worst reefs, and suggested that the current scores were unlikely to remain stable through time because of low redundancy. Accounting for the presence of marine protected area (MPA networks in statistical models did little to improve the models' predictive capabilities, suggesting limited efficacy of MPAs when grouped together across the region. Yet, localized benefits of MPAs existed and are expected to increase over time. Sensitivity analyses suggested that (i grazing by large herbivores, (ii high functional diversity of herbivores, and (iii high predator biomass were most sensitive to fishing pressure, and were required for high ecosystem-condition scores. Linking comprehensive fisheries management policies with these sensitive metrics, and targeting the management of pollution, will strengthen the Micronesia Challenge and preserve ecosystem

  20. Understanding and Managing the Effects of Climate Change on Ecosystem Services in the Rocky Mountains

    Directory of Open Access Journals (Sweden)

    Jessica E. Halofsky

    2017-08-01

    Full Text Available Public lands in the US Rocky Mountains provide critical ecosystem services, especially to rural communities that rely on these lands for fuel, food, water, and recreation. Climate change will likely affect the ability of these lands to provide ecosystem services. We describe 2 efforts to assess climate change vulnerabilities and develop adaptation options on federal lands in the Rocky Mountains. We specifically focus on aspects that affect community economic security and livelihood security, including water quality and quantity, timber, livestock grazing, and recreation. Headwaters of the Rocky Mountains serve as the primary source of water for large populations, and these headwaters are located primarily on public land. Thus, federal agencies will play a key role in helping to protect water quantity and quality by promoting watershed function and water conservation. Although increased temperatures and atmospheric concentration of CO2 have the potential to increase timber and forage production in the Rocky Mountains, those gains may be offset by wildfires, droughts, insect outbreaks, non-native species, and altered species composition. Our assessment identified ways in which federal land managers can help sustain forest and range productivity, primarily by increasing ecosystem resilience and minimizing current stressors, such as invasive species. Climate change will likely increase recreation participation. However, recreation managers will need more flexibility to adjust practices, provide recreation opportunities, and sustain economic benefits to communities. Federal agencies are now transitioning from the planning phase of climate change adaptation to implementation to ensure that ecosystem services will continue to be provided from federal lands in a changing climate.

  1. Landscape structure mediates the effects of a stressor on field vole populations

    DEFF Research Database (Denmark)

    Dalkvist, Trine; Sibly, Richard M.; Topping, Christopher John

    2013-01-01

    Spatio-temporal landscape heterogeneity has rarely been considered in population-level impact assessments. Here we test whether landscape heterogeneity is important by examining the case of a pesticide applied seasonally to orchards which may affect non-target vole populations, using a validated ...... results show that accurate prediction of population impact cannot be achieved without taking account of landscape structure. The specifics of landscape structure and habitat connectivity are likely always important in mediating the effects of stressors....

  2. The effects of nationality differences and work stressors on work adjustment for foreign nurse aides

    Directory of Open Access Journals (Sweden)

    Yang Hsieh

    2011-08-01

    Full Text Available Abstract Background The main purpose of this study was to discuss the nationality differences of foreign nurse aides and the effect of work stressors influencing work adjustment. And of helping them adapt to Taiwanese society, we summarized the difficulties that foreign nurse aides face in Taiwan. Methods The subjects included 80 foreign nurse aides from the Philippines, Indonesia, and Vietnam who worked in long-term care facilities in Tao Yuan County. We recruited volunteers at the participating facilities to complete the anonymous questionnaires. The return rate of the questionnaire was 88.75%. The validated instruments of Hershenson's (1981 and Schaefer and Moos (1993 were adopted to measure work stressors and work adjustment, respectively. A forward-backward translation process was used in this study. Results Indonesian foreign nurse aides respect their work, and are better workers than Vietnamese and Filipino nurse aids in many respects, which shows how the nationality of the foreign nurse aides might affect work adjustment. The stress created from patient care tasks influenced the foreign nurse aides' personal relationships at work and also affected their attitude when they performed their tasks. In addition, pressure from their supervisors might have affected their work skills, work habits, personal relationships, self-concepts or work attitudes. Moreover, a heavy workload and improper scheduling might have affected the personal relationships and work attitudes of the foreign nurse aides. It was found that work stressors had a significant correlation with work adjustment. Conclusions The results of the present study indicate that training programs are important factors for work adjustment among foreign nurse aides. Furthermore, celebration and leisure activities could be provided to release them from work stressors. More effort should be put into improving the working environment, namely providing a more supportive and enriching

  3. Local stressors reduce coral resilience to bleaching.

    Science.gov (United States)

    Carilli, Jessica E; Norris, Richard D; Black, Bryan A; Walsh, Sheila M; McField, Melanie

    2009-07-22

    Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

  4. Montessori Early Childhood Teacher Perceptions of Family Priorities and Stressors

    Science.gov (United States)

    Epstein, Ann

    2015-01-01

    Teachers of young children work closely with families. One component of teacher-family partnerships is teachers' understanding of family priorities and stressors. This study examines Montessori Early Childhood (ages three through six) teacher perceptions of family priorities and stressors through an analysis of responses to two parallel surveys.…

  5. Developing a multi-stressor gradient for coral reefs

    Science.gov (United States)

    Coral reefs are often found near coastal waters where multiple anthropogenic stressors co-occur at areas of human disturbance. Developing coral reef biocriteria under the U.S. Clean Water Act requires relationships between anthropogenic stressors and coral reef condition to be es...

  6. Emotional Competence and Stressors of Female School Teachers

    Science.gov (United States)

    Holeyannavar, P. G.; Itagi, S. K.

    2011-01-01

    A study on emotional competence and stressors of 105 primary school teachers was conducted in Dharwad in 2009. Emotional competence was assessed using EC- scale and stressors by stress inventory for teachers (SIT). Results revealed that majority of the teachers (89.5%) showed average to competent levels of emotional competence, followed by 6.7 and…

  7. Development of Optimal Stressor Scenarios for New Operational Energy Systems

    Science.gov (United States)

    2017-12-01

    OPTIMAL STRESSOR SCENARIOS FOR NEW OPERATIONAL ENERGY SYSTEMS by Geoffrey E. Fastabend December 2017 Thesis Advisor: Alejandro S... ENERGY SYSTEMS 5. FUNDING NUMBERS 6. AUTHOR(S) Geoffrey E. Fastabend 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School...developed and tested simulation model for operational energy related systems in order to develop better stressor scenarios for acceptance testing

  8. Perceived stressors of oral hygiene students in the dental environment

    African Journals Online (AJOL)

    Perceived stressors of oral hygiene students in the dental environment. ... with patients and communities, which may add to the stressors inherent to university life. ... (ii) perceived sources of stress, using a modified Dental Environment Stress (DES) questionnaire; and (iii) burnout, using the Maslach Burnout Inventory (MBI).

  9. Which Stressors Increase the Odds of College Binge Drinking?

    Science.gov (United States)

    Pedersen, Daphne E.

    2017-01-01

    College binge drinking has been linked to student stress. Which among a variety of stressors are more likely to result in problem drinking? In this paper, the relative influence of three types of stressors on college binge drinking is considered, including the academic, interpersonal, and developmental (e.g., making decisions about the future,…

  10. Interpersonal Stressors Predict Ghrelin and Leptin Levels in Women

    Science.gov (United States)

    Jaremka, Lisa M.; Belury, Martha A.; Andridge, Rebecca R.; Malarkey, William B.; Glaser, Ronald; Christian, Lisa; Emery, Charles F.; Kiecolt-Glaser, Janice K.

    2014-01-01

    Objective Stressful events enhance risk for weight gain and adiposity. Ghrelin and leptin, two hormones that are implicated in appetite regulation, may link stressful events to weight gain; a number of rodent studies suggest that stressors increase ghrelin production. The present study investigated the links among daily stressors, ghrelin and leptin, and dietary intake in humans. Method Women (N = 50) completed three study appointments that were scheduled at least 2 weeks apart. At each visit, women arrived fasting and ate a standardized breakfast and lunch. Blood samples were collected 45 minutes after each meal. Women completed a self-report version of the Daily Inventory of Stressful Events (DISE) at each appointment. Two composites were created from the DISE data, reflecting the number of stressors that did and did not involve interpersonal tension. Results Women who experienced more stressors involving interpersonal tension had higher ghrelin and lower leptin levels than those who experienced fewer interpersonal stressors. Furthermore, women who experienced more interpersonal stressors had a diet that was higher in calories, fat, carbohydrates, protein, sugar, sodium, and fiber, and marginally higher in cholesterol, vegetables (but not fruits), vitamin A, and vitamin C. Stressors that did not involve interpersonal tension were unrelated to ghrelin and leptin levels or any of the dietary components examined. Conclusions These data suggest that ghrelin and leptin may link daily interpersonal stressors to weight gain and obesity. PMID:25032903

  11. US exposure to multiple landscape stressors and climate change

    Science.gov (United States)

    Becky K. Kerns; John B. Kim; Jeffrey D. Kline; Michelle A. Day

    2016-01-01

    We examined landscape exposure to wildfire potential, insects and disease risk, and urban and exurban development for the conterminous US (CONUS). Our analysis relied on spatial data used by federal agencies to evaluate these stressors nationally. We combined stressor data with a climate change exposure metric to identify when temperature is likely to depart from...

  12. Daily Stressors in School-Age Children: A Multilevel Approach

    Science.gov (United States)

    Escobar, Milagros; Alarcón, Rafael; Blanca, María J.; Fernández-Baena, F. Javier; Rosel, Jesús F.; Trianes, María Victoria

    2013-01-01

    This study uses hierarchical or multilevel modeling to identify variables that contribute to daily stressors in a population of schoolchildren. Four hierarchical levels with several predictive variables were considered: student (age, sex, social adaptation of the student, number of life events and chronic stressors experienced, and educational…

  13. Sensory input from the osphradium modulates the response to memory-enhancing stressors in Lymnaea stagnalis.

    Science.gov (United States)

    Karnik, Vikram; Braun, Marvin; Dalesman, Sarah; Lukowiak, Ken

    2012-02-01

    In the freshwater environment species often rely on chemosensory information to modulate behavior. The pond snail, Lymnaea stagnalis, is a model species used to characterize the causal mechanisms of long-term memory (LTM) formation. Chemical stressors including crayfish kairomones and KCl enhance LTM formation (≥24 h) in Lymnaea; however, how these stressors are sensed and the mechanism by which they affect the electrophysiological properties of neurons necessary for memory formation are poorly understood. Here, we assessed whether the osphradium, a primary chemosensory organ in Lymnaea, modulates LTM enhancement. To test this we severed the osphradial nerve proximal to the osphradium, using sham-operated animals as controls, and assessed the behavioral and electrophysiological response to crayfish kairomones and KCl. We operantly conditioned aerial respiratory behavior in intact, sham and osphradially cut animals, and tested for enhanced memory formation after exposure to the chemical stressors. Sham-operated animals displayed the same memory enhancement as intact animals but snails with a severed osphradial nerve did not show LTM enhancement. Extracellular recordings made from the osphradial nerve demonstrate that these stressors evoked afferent sensory activity. Intracellular recordings from right pedal dorsal 1 (RPeD1), a neuron necessary for LTM formation, demonstrate that its electrophysiological activity is altered by input from the osphradium following exposure to crayfish kairomones or KCl in sham and intact animals but no response is seen in RPeD1 in osphradially cut animals. Therefore, sensory input from the osphradium is necessary for LTM enhancement following exposure to these chemical stressors.

  14. Experience Corps Baltimore: Exploring the Stressors and Rewards of High-intensity Civic Engagement.

    Science.gov (United States)

    Varma, Vijay R; Carlson, Michelle C; Parisi, Jeanine M; Tanner, Elizabeth K; McGill, Sylvia; Fried, Linda P; Song, Linda H; Gruenewald, Tara L

    2015-12-01

    Experience Corps (EC) represents a high-intensity, intergenerational civic engagement activity where older adults serve as mentors and tutors in elementary schools. Although high-intensity volunteer opportunities are designed to enhance the health and well being of older adult volunteers, little is known about the negative and positive aspects of volunteering unique to intergenerational programs from the volunteer's perspective. Stressors and rewards associated with volunteering in EC were explored in 8 focus group discussions with 46 volunteers from EC Baltimore. Transcripts were coded for frequently expressed themes. Participants reported stressors and rewards within 5 key domains: intergenerational (children's problem behavior, working with and helping children, observing/facilitating improvement or transformation in a child, and developing a special connection with a child); external to EC (poor parenting and children's social stressors); interpersonal (challenges in working with teachers and bonding/making social connections); personal (enjoyment, self-enhancement/achievement, and being/feeling more active); and structural (satisfaction with the structural elements of the EC program). Volunteers experienced unique intergenerational stressors related to children's problem behavior and societal factors external to the EC program. Overall, intergenerational, interpersonal, and personal rewards from volunteering, as well as program structure may have balanced the stress associated with volunteering. A better understanding of stressors and rewards from high-intensity volunteer programs may enhance our understanding of how intergenerational civic engagement volunteering affects well being in later life and may inform project modifications to maximize such benefits for future volunteers and those they serve. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e

  15. Financial satisfaction and financial stressors in marital satisfaction.

    Science.gov (United States)

    Archuleta, Kristy L; Britt, Sonya L; Tonn, Teresa J; Grable, John E

    2011-04-01

    Using a sample of 310 married respondents from one U.S. Midwestern state, a test was conducted to examine the association of financial satisfaction and financial stressors in a spouse's decision to stay married to the same person or leave the relationship. The role of demographic and socioeconomic variables, religiosity, psychological constructs, financial satisfaction, and financial stressors as factors influencing marital satisfaction was tested. Financial stressors were measured using a list of financial stressors adapted from the literature. Financial satisfaction was measured with a one-item scale. The Kansas Marital Satisfaction Scale was used as a validation tool to assess whether individuals would marry or not marry again. Religiosity and financial satisfaction were positively associated with marital satisfaction. A negative interaction between financial satisfaction and financial stressors was also noted. Findings suggest that respondents who are financially satisfied tend to be more stable in their marriages.

  16. Coastal Wetland Ecosystem Responses to Climate Change: the Role of Macroclimatic Drivers along the Northern Gulf of Mexico

    Science.gov (United States)

    Osland, M. J.; Enwright, N.; Day, R. H.; Gabler, C. A.; Stagg, C. L.; From, A. S.

    2014-12-01

    Across the globe, macroclimatic drivers greatly influence coastal wetland ecosystem structure and function. However, changing macroclimatic conditions are rarely incorporated into coastal wetland vulnerability assessments. Here, we quantify the influence of macroclimatic drivers upon coastal wetland ecosystems along the Northern Gulf of Mexico (NGOM) coast. From a global perspective, the NGOM coast provides several excellent opportunities to examine the effects of climate change upon coastal wetlands. The abundant coastal wetland ecosystems in the region span two major climatic gradients: (1) a winter temperature gradient that crosses temperate to tropical climatic zones; and (2) a precipitation gradient that crosses humid to semi-arid zones. We present analyses where we used geospatial data (historical climate, hydrology, and coastal wetland coverage) and field data (soil, elevation, and plant community composition and structure) to quantify climate-mediated ecological transitions. We identified winter climate and precipitation-based thresholds that separate mangrove forests from salt marshes and vegetated wetlands from unvegetated wetlands, respectively. We used simple distribution and abundance models to evaluate the potential ecological effects of alternative future climate change scenarios. Our results illustrate and quantify the importance of macroclimatic drivers and indicate that climate change could result in landscape-scale changes in coastal wetland ecosystem structure and function. These macroclimate-mediated ecological changes could affect the supply of some ecosystem goods and services as well as the resilience of these ecosystems to stressors, including accelerated sea level rise. Collectively, our findings highlight the importance of incorporating macroclimatic drivers within future-focused coastal wetland vulnerability assessments.

  17. Soil-based ecosystem services

    DEFF Research Database (Denmark)

    Ghaley, Bhim Bahadur; Porter, John Roy; Sandhu, Harpinder S.

    2014-01-01

    Among the soil-based ecosystem services (ES), nutrient cycling and carbon sequestration have direct influence on the biogeochemical cycles and greenhouse gas emissions affecting provision of other ES that support human existence. We reviewed methods to assess the two key ES by identifying...... their strengths and weaknesses and have made suggestions for using appropriate methods for better understanding of the ecosystem functions for the provision of ES. Relevant papers for the review were chosen on the basis of (i) diversity of studies on the two key ES in different ecosystems, (ii) methodologies...... applied and (iii) detailed descriptions of the trial locations in terms of vegetation, soil type, location and climatic information. We concluded that (i) elemental stoichiometrical ratios could be a potential approach to assess the health of ecosystems in terms of provision of the two ES discussed, (ii...

  18. Incorporating Ecosystem Services into Community-level ...

    Science.gov (United States)

    EPA’s Office of Research and Development’s Sustainable and Healthy Communities Research Program is developing tools and approaches to incorporate ecosystem goods and services concepts into community-level decision-making. The San Juan Community Study is one of a series of coordinated community studies, which also include Mobile Bay, AL, Great Lakes Areas of Concern, and the Pacific Northwest. Common elements across the community studies include a focus on watershed management and national estuary programs (National Estuary Program, National Estuarine Research Reserve System). San Juan, Puerto Rico, is unique from the other community studies in that it is located in a highly urbanized watershed integrated with a number of freshwater and coastal ecosystems. The San Juan Community Study will explore linkages between watershed management decisions (e.g., dredging canals, restoration of mangrove buffers, sewage discharge interventions, climate adaptive strategies) targeting priority stressors (e.g., nutrients, contaminants, and pathogens; aquatic debris; habitat loss; modified hydrology and water circulation; sea level rise; storm intensity and frequency) effecting the condition of ecosystems (e.g., estuarine habitats and fish, as well as the connected terrestrial and coastal ecosystems), associated ecosystem goods and services (e.g., tourism and recreation, fishing, nutrient & sediment retention, contaminant processing, carbon sequestration, flood protection),

  19. Physiotherapy students' perceived stress, stressors, and reactions to stressors : a comparative study between Sweden and The Netherlands

    NARCIS (Netherlands)

    Hodselmans, Audy-Paul; Hemdal, Elin; Lundberg, Sophie; Bjarnegård, Anna; Hobbelen, Hans; Svantesson, Ulla

    2017-01-01

    BACKGROUND AND PURPOSE: Studies of healthcare students report increased levels of stress, with academic pressures being the greatest source. The objective of this study was to examine the differences in the overall stress level, stressors, and reactions to stressors between physiotherapy students at

  20. The association between psychosocial and structural-level stressors and HIV injection drug risk behavior among Malaysian fishermen: A cross-sectional study

    OpenAIRE

    Michalopoulos, Lynn Murphy; Jiwatram-Negr?n, Tina; Choo, Martin K. K.; Kamarulzaman, Adeeba; El-Bassel, Nabila

    2016-01-01

    Background Malaysian fishermen have been identified as a key-affected HIV population with HIV rates 10 times higher than national rates. A number of studies have identified that psychosocial and structural-level stressors increase HIV injection drug risk behaviors. The purpose of this paper is to examine psychosocial and structural-level stressors of injection drug use and HIV injection drug risk behaviors among Malaysian fishermen. Methods The study employs a cross-sectional design using res...

  1. Quantitative analysis of oyster larval proteome provides new insights into the effects of multiple climate change stressors

    KAUST Repository

    Dineshram, Ramadoss; Chandramouli, Kondethimmanahalli; Ko, Ginger Wai Kuen; Zhang, Huoming; Qian, Pei-Yuan; Ravasi, Timothy; Thiyagarajan, Vengatesen

    2016-01-01

    might be affected in a future ocean, we examined changes in the proteome of metamorphosing larvae under multiple stressors: decreased pH (pH 7.4), increased temperature (30 °C), and reduced salinity (15 psu). Quantitative protein expression profiling

  2. An Examination of Culturally Relevant Stressors, Coping, Ethnic Identity, and Subjective Well-Being in Urban, Ethnic Minority Adolescents

    Science.gov (United States)

    Vera, Elizabeth M.; Vacek, Kimberly; Coyle, Laura D.; Stinson, Jennifer; Mull, Megan; Doud, Katherine; Buchheit, Christine; Gorman, Catherine; Hewitt, Amber; Keene, Chesleigh; Blackmon, Sha'kema; Langrehr, Kimberly J.

    2011-01-01

    This study explored relations between culturally relevant stressors (i.e., urban hassles, perceived discrimination) and subjective well-being (SWB; i.e., positive/ negative affect, life satisfaction) to examine whether ethnic identity and/or coping strategies would serve as moderators of the relations between stress and SWB for 157 urban, ethnic…

  3. The Impact of Child-Related Stressors on the Psychological Functioning of Lower-Income Mothers after Hurricane Katrina

    Science.gov (United States)

    Lowe, Sarah R.; Chan, Christian S.; Rhodes, Jean E.

    2011-01-01

    In the present study, the authors examined the role of child-related stressors in the psychological adjustment of lower-income, primarily unmarried and African American, mothers (N = 386). All participants lived in areas affected by Hurricane Katrina, and about a third were also exposed to Hurricane Rita (30.3%, n = 117). Lacking knowledge of a…

  4. Network Skewness Measures Resilience in Lake Ecosystems

    Science.gov (United States)

    Langdon, P. G.; Wang, R.; Dearing, J.; Zhang, E.; Doncaster, P.; Yang, X.; Yang, H.; Dong, X.; Hu, Z.; Xu, M.; Yanjie, Z.; Shen, J.

    2017-12-01

    Changes in ecosystem resilience defy straightforward quantification from biodiversity metrics, which ignore influences of community structure. Naturally self-organized network structures show positive skewness in the distribution of node connections. Here we test for skewness reduction in lake diatom communities facing anthropogenic stressors, across a network of 273 lakes in China containing 452 diatom species. Species connections show positively skewed distributions in little-impacted lakes, switching to negative skewness in lakes associated with human settlement, surrounding land-use change, and higher phosphorus concentration. Dated sediment cores reveal a down-shifting of network skewness as human impacts intensify, and reversal with recovery from disturbance. The appearance and degree of negative skew presents a new diagnostic for quantifying system resilience and impacts from exogenous forcing on ecosystem communities.

  5. Immediate and Longer-Term Stressors and the Mental Health of Hurricane Ike Survivors

    OpenAIRE

    Lowe, Sarah R.; Tracy, Melissa; Cerdá, Magdalena; Norris, Fran H.; Galea, Sandro

    2013-01-01

    Previous research has documented that individuals exposed to more stressors during disasters and their immediate aftermath (immediate stressors) are at risk of experiencing longer-term postdisaster stressors. Longer-term stressors, in turn, have been found to play a key role in shaping postdisaster psychological functioning. Few studies have simultaneously explored the links from immediate to longer-term stressors, and from longer-term stressors to psychological functioning,...

  6. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  7. Fungi and their role in corals and coral reef ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Ravindran, J.

    fungal hyphae have on corals, their mechanism of penetration and the role their enzymes play in this process. 3.2. Fungi as pathogens in reef ecosystems Besides natural disasters and climate warming, diseases have contributed to coral decline... defence mechanisms against predation, biofouling, diseases, environmental perturbations and other stressors. These chemicals are either synthesized by the organisms themselves or their endobiontic microorganisms. If these valuable compounds...

  8. Relationship functioning moderates the association between depressive symptoms and life stressors.

    Science.gov (United States)

    Trombello, Joseph M; Schoebi, Dominik; Bradbury, Thomas N

    2011-02-01

    Data from 172 newlywed couples were collected over the first 4 years of marriage to test how behaviors demonstrated during marital interactions moderate associations between depressive symptoms and subsequent life stressors. Depressive symptoms and behaviors coded from problem-solving and social support interactions were analyzed as predictors of nonmarital stressors that were interpersonal and dependent on the participant's actions. Behavioral codes were found to moderate 3 of 16 symptom-to-life event associations for husbands. Husbands' reports of more depressive symptoms predicted greater levels of stress when husbands' positive affect and hard negative affect during problem-solving were relatively infrequent and when wives made frequent displays of positive behaviors during husbands' support topics. These effects remained after controlling for marital satisfaction. For wives, behavioral moderators did not interact with depressive symptoms to predict changes in stress, but marital satisfaction consistently interacted with depressive symptoms to predict future stressors beyond interpersonal behaviors. Specifically, for wives, stress generation was more evident when relationship satisfaction was low than when it was high. Our results, though different for men and women, suggest that relationship functioning can alter associations between depressive symptoms and life stress in the early years of marriage. (PsycINFO Database Record (c) 2011 APA, all rights reserved). PsycINFO Database Record (c) 2011 APA, all rights reserved.

  9. Super heroes and lucky duckies: Racialized stressors among teachers.

    Science.gov (United States)

    Rauscher, Lauren; Wilson, Bianca D M

    2017-04-01

    This article explores the complex relationships between race and occupational stressors among an ethnically diverse sample of high school teachers and their implications for women's mental health. Interviews with Black, White, and Mexican American teachers suggest that workplaces are organized by subtle forms of gender and racial discrimination as well as White racial privilege; this context shapes women's experiences of occupational stressors. The data indicate that teachers experience racially specific stressors at work and make racially specific appraisals about common stressors among all teachers. Black and Mexican American women report chronic strains, such as differential workloads, perceptions of incompetence, and lack of support from administrators, whereas White teachers report, yet minimize, sexual harassment from male colleagues. Student misbehavior, a stressor shared by all teachers, is experienced and understood as a personal failing by White teachers and as a manifestation of systemic racism by teachers of color. The interviews offer important insights into the ways professional workplaces remain an arena marked by racial inequality and White privilege and that racialized stressors are differentially distributed among women. Findings support claims from intersectionality in that race, racism, and racial privilege operate in multiplicative ways that create different constellations of occupational stressors among women, which in turn have implications for wellbeing. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. Impact of Noncaregiving-Related Stressors on Informal Caregiver Outcomes.

    Science.gov (United States)

    Austrom, Mary Guerriero; Lu, Yvonne Yueh-Feng; Perkins, Anthony J; Boustani, Malaz; Callahan, Christopher M; Hendrie, Hugh C

    2014-08-01

    Caregivers of persons with dementia are stressed. Stressors not related to care recipients' needs impact caregiver outcomes, yet are seldom reported. The purpose of this study was to report the most stressful events experienced by spouse caregivers of older adults with Alzheimer s disease during a 6-month period. 31 caregivers completed the Most Stressful Event form, Patient Health Questionnaire (PHQ-9) and the Revised Memory Behavioral Problem Checklist (R-MBPC). Fisher's exact test and two-sample t-test were used to compare Most Stressful Events between caregivers. ANOVA model tested whether the PHQ-9 and R-MBPC subscales differed by stressor. Caregivers reported no stressors 21.5% of the time, 1-2 stressors 25% of the time, and 3 stressors 53% of the time with 318 stressors reported in total. Care recipient needs (30.2%), caregiver needs (26.7%), and decision-making (16.7%) were the most frequently reported stressors. Using a mixed effects model, there were associations between the Most Stressful Events and depression (p = 0.016), mobility (p = 0.024) and caregiver issues (p = 0.009) subscales of R-MBPC. Results can be used to develop targeted intervention and support strategies for spouse caregivers experiencing non-caregiving related stressorsas well as the traditional challenges with caregiving related issues. © The Author(s) 2014.

  11. Perceived stressors of oral hygiene students in the dental environment

    Directory of Open Access Journals (Sweden)

    Chrisleen Rayner

    2016-05-01

    Full Text Available Background. University students are exposed to a multitude of stressors that may impact on their performance. The nature of health sciences education generally involves early engagement with patients and communities, which may add to the stressors inherent to university life. There is sparse information on stressors in the oral hygiene educational environment. Objective. To determine perceived stressors and the level of burnout among oral hygiene students at the University of the Western Cape, Cape Town, South Africa. Method. A descriptive, cross-sectional study design was used. The study sample included all students in the Bachelor of Oral Health (BOH degree during 2012 (N=89. A self-administered questionnaire was used to gather data. Three parameters were measured, i.e. (i demographic characteristics; (ii perceived sources of stress, using a modified Dental Environment Stress (DES questionnaire; and (iii burnout, using the Maslach Burnout Inventory (MBI. Results. Respondents were mostly female (74% and primarily in the 18 - 25-year age group (92%. First- and 2nd-year students identified fear of failing and study load as major stressors. Stressors related to a lack of basic needs were identified as major stressors by 25% of 1st-year students. Third-year students identified clinical quotas, supervision and patients being late as major stressors. MBI scores indicated that students were not at risk for burnout; however, most students (66.2% scored high on emotional exhaustion (EE. Conclusion. Oral hygiene students identified stressors in their learning environment. There was a progressive increase in EE across academic years. The results suggest that interventions should be tailored for specific academic year groups.

  12. Social support, stressors, and frailty among older Mexican American adults.

    Science.gov (United States)

    Peek, M Kristen; Howrey, Bret T; Ternent, Rafael Samper; Ray, Laura A; Ottenbacher, Kenneth J

    2012-11-01

    There is little research on the effects of stressors and social support on frailty. Older Mexican Americans, in particular, are at higher risk of medical conditions, such as diabetes, that could contribute to frailty. Given that the Mexican American population is rapidly growing in the United States, it is important to determine whether there are modifiable social factors related to frailty in this older group. To address the influence of social support and stressors on frailty among older Mexican Americans, we utilized five waves of the Hispanic Established Populations for the Epidemiologic Study of the Elderly (Hispanic EPESE) to examine the impact of stressors and social support on frailty over a 12-year period. Using a modified version of the Fried and Walston Frailty Index, we estimated the effects of social support and stressors on frailty over time using trajectory modeling (SAS 9.2, PROC TRAJ). We first grouped respondents according to one of three trajectories: low, progressive moderate, and progressive high frailty. Second, we found that the effects of stressors and social support on frailty varied by trajectory and by type of stressor. Health-related stressors and financial strain were related to increases in frailty over time, whereas social support was related to less-steep increases in frailty. Frailty has been hypothesized to reflect age-related physiological vulnerability to stressors, and the analyses presented indicate partial support for this hypothesis in an older sample of Mexican Americans. Future research needs to incorporate measures of stressors and social support in examining those who become frail, especially in minority populations.

  13. Shift work as an oxidative stressor

    Directory of Open Access Journals (Sweden)

    Pasalar Parvin

    2005-12-01

    Full Text Available Abstract Background Some medical disorders have higher prevalence in shift workers than others. This study was designed to evaluate the effect of night-shift-working on total plasma antioxidant capacity, with respect to the causative role of oxidative stress in induction of some of these disorders. Methods Two blood samples were taken from 44 workers with a rotational shift schedule, one after their day shift and one after their night shift. The total plasma antioxidant capacity of each worker was measured through the FRAP method. The impacts of age and weight were also assessed. Results The total plasma antioxidant capacity was measured in 44 shift-workers with a mean age of 36.57 years (SD: 10.18 and mean BMI of 26.06 (SD: 4.37 after their day and night shifts. The mean reduction of total plasma antioxidant capacity after the night shift was 105.8 μmol/L (SD: 146.39. Also, a significant correlation was shown between age and weight and total plasma antioxidant capacity. Age and weight were found to be inversely related to total plasma antioxidant capacity; as age and weight increased, the total plasma antioxidant capacity decreased. Conclusion Shift work can act as an oxidative stressor and may induce many medical disorders. Aging and obesity in shift workers makes them more sensitive to this hazardous effect.

  14. Amphibian decline: an integrated analysis of multiple stressor effects

    Energy Technology Data Exchange (ETDEWEB)

    Linder, G.; Krest, S.K.; Sparkling, D.W. (eds.)

    2003-07-01

    Environmental effects of stressors on amphibians have received increased attention but little is known about the effects of these stressors on amphibian populations. The workshop addressed this issue. The proceedings contain 15 chapters, two of which mention effects of coal combustion wastes. These are: Chapter 4: Chemical stressors, by J.H. Burkhart, J.R. Bidwell, D.J. Fort, S.R. Sheffield, and Chapter 8E: Anthropogenic activities producing sink habitats for amphibians in the local landscape: a case study of lethal and sublethal effects of coal combustion residues in the aquatic environment by C.L. Rose and W.A. Hopkins.

  15. Ecosystem Services in Environmental Science Literacy

    Science.gov (United States)

    Ruppert, John Robert

    2015-01-01

    Human beings depend on a set of benefits that emerge from functioning ecosystems, termed Ecosystem Services (ES), and make decisions in everyday life that affect these ES. Recent advancements in science have led to an increasingly sophisticated understanding of ES and how they can be used to inform environmental decision-making. Following suit, US…

  16. Biological invasions in forest ecosystems

    Science.gov (United States)

    Andrew M. Liebhold; Eckehard G. Brockerhoff; Susan Kalisz; Martin A. Nuñez; David A. Wardle; Michael J. Wingfield

    2017-01-01

    Forests play critical roles in global ecosystem processes and provide numerous services to society. But forests are increasingly affected by a variety of human influences, especially those resulting from biological invasions. Species invading forests include woody and herbaceous plants, many animal species including mammals and invertebrates, as well as a variety of...

  17. The impact of extreme flooding events and anthropogenic stressors on the macrobenthic communities’ dynamics

    Science.gov (United States)

    Cardoso, P. G.; Raffaelli, D.; Lillebø, A. I.; Verdelhos, T.; Pardal, M. A.

    2008-02-01

    Marine and coastal environments are among the most ecologically and socio-economically important habitats on Earth. However, climate change associated with a variety of anthropogenic stressors (e.g. eutrophication) may interact to produce combined impacts on biodiversity and ecosystem functioning, which in turn will have profound implications for marine ecosystems and the economic and social systems that depend upon them. Over period 1980-2000, the environment of the Mondego estuary, Portugal, has deteriorated through eutrophication, manifested in the replacement of seagrasses by opportunistic macroalgae, degradation of water quality and increased turbidity, and the system has also experienced extreme flood events. A restoration plan was implemented in 1998 which aimed to reverse the eutrophication effects, especially to restore the original natural seagrass ( Zostera noltii) community. This paper explores the interactions between extreme weather events (e.g. intense floods) and anthropogenic stressors (e.g. eutrophication) on the dynamics of the macrobenthic assemblages and the socio-economic implications that follow. We found that during the previous decade, the intensification of extreme flooding events had significant effects on the structure and functioning of macrobenthic communities, specifically a decline in total biomass, a decline in species richness and a decline in suspension feeders. However, the earlier eutrophication process also strongly modified the macrobenthic community, seen as a decline in species richness, increase in detritivores and a decline in herbivores together with a significant increase in small deposit-feeding polychaetes. After the implementation of the management plan, macrobenthic assemblages seemed to be recovering from eutrophication, but it is argued here that those earlier impacts reduced system stability and the resilience of the macrobenthic assemblages, so that its ability to cope with other stressors was compromised. Thus

  18. Saliendo Adelante: Stressors and Coping Strategies Among Immigrant Latino Men Who Have Sex With Men in a Nontraditional Settlement State.

    Science.gov (United States)

    Gilbert, Paul A; Barrington, Clare; Rhodes, Scott D; Eng, Eugenia

    2016-11-01

    Immigrant Latino men who have sex with men (MSM) are marginalized along multiple dimensions (e.g., ethnicity, sexual orientation, language use), which can negatively affect their health and well-being. As little is known about how this subgroup experiences the stress of marginalization and how, in turn, they cope with such stress, this study investigated stressors and coping strategies to better understand the factors shaping Latino MSM health. Assisted by a community advisory committee, we conducted in-depth interviews with 15 foreign-born Latino MSM in a nontraditional settlement state. Drawing on grounded theory methods, we analyzed transcripts iteratively to identify processes and characterize themes. Results were confirmed in member check interviews (n = 4) and findings were further contextualized through key informant interviews (n = 3). Participants reported ubiquitous, concurrent stressors due to being an immigrant, being a sexual minority, and being working poor. In particular, homophobia within families and local Latino communities was seen as pervasive. Some participants faced additional stressors due to being undocumented and not being Mexican. Participants drew on four types of coping strategies, with no dominant coping response: passive coping (i.e., not reacting to stressors); attempting to change stressors; seeking social support; and seeking distractions. Family ties, especially with mothers, provided key emotional support but could also generate stress related to participants' sexuality. This study lays a foundation for future work and is particularly relevant for Latino MSM in nontraditional settlement states. Findings may inform future interventions to reduce stressors and increase resiliency, which can positively affect multiple health outcomes. © The Author(s) 2016.

  19. Workplace Discrimination: An Additional Stressor for Internationally Educated Nurses.

    Science.gov (United States)

    Baptiste, Maria M

    2015-08-18

    Discrimination against internationally educated nurses (IENs) remains a seldom-explored topic in the United States. Yet, the literature describing experiences of IENs indicates that some do experience workplace discrimination as an additional workplace stressor. IENs view this discrimination as an obstacle to career advancement and professional recognition. Consequences of workplace discrimination affect IENs' physical and psychological well being, the quality of patient care, and healthcare organizational costs. In anticipation of future nursing shortages, understanding and minimizing workplace discrimination will benefit nurses, patients, and healthcare organizations. In this article the author addresses motivation and challenges associated with international nurse migration and immigration, relates these challenges to Roy's theoretical framework, describes workplace discrimination, and reviews both consequences of and evidence for workplace discrimination. Next, she considers the significance of this discrimination for healthcare agencies, and approaches for decreasing stress for IENs during their transition process. She concludes that workplace discrimination has a negative, multifaceted effect on both professional nursing and healthcare organizations. Support measures developed to promote mutual respect among all nurses are presented.

  20. Small diversity effects on ocean primary production under environmental change in a diversity-resolving ocean ecosystem model

    DEFF Research Database (Denmark)

    Prowe, Friederike; Pahlow, M.; Dutkiewicz, S.

    2013-01-01

    Marine ecosystem models used to investigate how global change affects ocean ecosystems and their functioning typically omit pelagic diversity. Diversity, however, can affect functions such as primary production and their sensitivity to environmental changes. Using a global ocean ecosystem model...... the diversity effects on ecosystem functioning captured in ocean ecosystem models....

  1. Using macroinvertebrate assemblages and multiple stressors to infer urban stream system condition: A case study in the central US

    Science.gov (United States)

    Nichols, John W.; Hubbart, Jason A.; Poulton, Barry C.

    2016-01-01

    Characterizing the impacts of hydrologic alterations, pollutants, and habitat degradation on macroinvertebrate species assemblages is of critical value for managers wishing to categorize stream ecosystem condition. A combination of approaches including trait-based metrics and traditional bioassessments provides greater information, particularly in anthropogenic stream ecosystems where traditional approaches can be confounded by variously interacting land use impacts. Macroinvertebrates were collected from two rural and three urban nested study sites in central Missouri, USA during the spring and fall seasons of 2011. Land use responses of conventional taxonomic and trait-based metrics were compared to streamflow indices, physical habitat metrics, and water quality indices. Results show that biotic index was significantly different (p habitats in urban reaches contained 21 % more (p = 0.03) multivoltine organisms, which was positively correlated to the magnitude of peak flows (r2 = 0.91, p = 0.012) suggesting that high flow events may serve as a disturbance in those areas. Results support the use of macroinvertebrate assemblages and multiple stressors to characterize urban stream system condition and highlight the need to better understand the complex interactions of trait-based metrics and anthropogenic aquatic ecosystem stressors.

  2. Assessing Sources of Stress to Aquatic Ecosystems: Using Biomarkers and Bioindicators to Characterize Exodure-Response Profiles of Anthropogenic Activities

    Energy Technology Data Exchange (ETDEWEB)

    Adams, S.M.

    1999-03-29

    Establishing causal relationships between sources of environmental stressors and aquatic ecosystem health if difficult because of the many biotic and abiotic factors which can influence or modify responses of biological systems to stress, the orders of magnitude involved in extrapolation over both spatial and temporal scales, and compensatory mechanisms such as density-dependent responses that operate in populations. To address the problem of establishing causality between stressors and effects on aquatic systems, a diagnostic approach, based on exposure-response profiles for various anthropogenic activities, was developed to help identify sources of stress responsible for effects on aquatic systems at ecological significant levels of biological organization (individual, population, community). To generate these exposure-effects profiles, biomarkers of exposure were plotted against bioindicators of corresponding effects for several major anthropogenic activities including petrochemical , pulp and paper, domestic sewage, mining operations, land-development activities, and agricultural activities. Biomarkers of exposure to environmental stressors varied depending on the type of anthropogenic activity involved. Bioindicator effects, however, including histopathological lesions, bioenergetic status, individual growth, reproductive impairment, and community-level responses were similar among many of the major anthropogenic activities. This approach is valuable to help identify and diagnose sources of stressors in environments impacted by multiple stressors. By identifying the types and sources of environmental stressors, aquatic ecosystems can be more effectively protected and managed to maintain acceptable levels of environmental quality and ecosystem fitness.

  3. Climate warming reduces fish production and benthic habitat in Lake Tanganyika, one of the most biodiverse freshwater ecosystems

    Science.gov (United States)

    Cohen, Andrew S.; Gergurich, Elizabeth L.; Kraemer, Benjamin M.; McGlue, Michael M.; McIntyre, Peter B.; Russell, James M.; Simmons, Jack D.; Swarzenski, Peter W.

    2016-01-01

    Warming climates are rapidly transforming lake ecosystems worldwide, but the breadth of changes in tropical lakes is poorly documented. Sustainable management of freshwater fisheries and biodiversity requires accounting for historical and ongoing stressors such as climate change and harvest intensity. This is problematic in tropical Africa, where records of ecosystem change are limited and local populations rely heavily on lakes for nutrition. Here, using a ∼1,500-y paleoecological record, we show that declines in fishery species and endemic molluscs began well before commercial fishing in Lake Tanganyika, Africa’s deepest and oldest lake. Paleoclimate and instrumental records demonstrate sustained warming in this lake during the last ∼150 y, which affects biota by strengthening and shallowing stratification of the water column. Reductions in lake mixing have depressed algal production and shrunk the oxygenated benthic habitat by 38% in our study areas, yielding fish and mollusc declines. Late-20th century fish fossil abundances at two of three sites were lower than at any other time in the last millennium and fell in concert with reduced diatom abundance and warming water. A negative correlation between lake temperature and fish and mollusc fossils over the last ∼500 y indicates that climate warming and intensifying stratification have almost certainly reduced potential fishery production, helping to explain ongoing declines in fish catches. Long-term declines of both benthic and pelagic species underscore the urgency of strategic efforts to sustain Lake Tanganyika’s extraordinary biodiversity and ecosystem services.

  4. Considering Environmental and Occupational Stressors in Cumulative Risk Assessments

    Science.gov (United States)

    While definitions vary across the global scientific community, cumulative risk assessments (CRAs) typically are described as exhibiting a population focus and analyzing the combined risks posed by multiple stressors. CRAs also may consider risk management alternatives as an anal...

  5. Military Occupational Stressors in Garrison, Training, and Deployed Environments

    National Research Council Canada - National Science Library

    Adler, Amy

    2004-01-01

    As part of the Walter Reed Army Institute of Research (WRAIR) program to model soldier stress, health, and performance, stressors are analyzed across a variety of environments in terms of their impact on military personnel...

  6. 338 Stressors and their Influence on Job Performance of Career ...

    African Journals Online (AJOL)

    Nekky Umera

    The purpose of this study was to determine stressors and how they influence university career ... staff are often faced with struggling to maintain a continual balance among .... time working, reporting and encountering stress in their work life.

  7. Environmental stressors alter relationships between physiology and behaviour.

    Science.gov (United States)

    Killen, Shaun S; Marras, Stefano; Metcalfe, Neil B; McKenzie, David J; Domenici, Paolo

    2013-11-01

    Although correlations have frequently been observed between specific physiological and behavioural traits across a range of animal taxa, the nature of these associations has been shown to vary. Here we argue that a major source of this inconsistency is the influence of environmental stressors, which seem capable of revealing, masking, or modulating covariation in physiological and behavioural traits. These effects appear to be mediated by changes in the observed variation of traits and differential sensitivity to stressors among phenotypes. Considering that wild animals routinely face a range of biotic and abiotic stressors, increased knowledge of these effects is imperative for understanding the causal mechanisms of a range of ecological phenomena and evolutionary responses to stressors associated with environmental change. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  8. Characterizing Risks of Exposures to Combined Stressors: An Overview

    Science.gov (United States)

    Cumulative risk assessment (CRA) addresses the impacts of multiple chemical and nonchemical stressors on communities, resulting from complex exposures for populations with a variety of vulnerabilities. These efforts focus on real world exposure scenarios and applications that ra...

  9. Physiological monitoring of team and task stressors

    Science.gov (United States)

    Orasanu, Judith; Tada, Yuri; Kraft, Norbert; Fischer, Ute

    2005-05-01

    Sending astronauts into space, especially on long-durations missions (e.g. three-year missions to Mars), entails enormous risk. Threats include both physical dangers of radiation, bone loss and other consequences of weightlessness, and also those arising from interpersonal problems associated with extended life in a high-risk isolated and confined environment. Before undertaking long-duration missions, NASA seeks to develop technologies to monitor indicators of potentially debilitating stress at both the individual and team level so that countermeasures can be introduced to prevent further deterioration. Doing so requires a better understanding of indicators of team health and performance. To that end, a study of team problem solving in a simulation environment was undertaken to explore effects of team and task stress. Groups of four males (25-45 yrs) engaged in six dynamic computer-based Antarctic search and rescue missions over four days. Both task and team stressors were manipulated. Physiological responses (ECG, respiration rate and amplitude, SCL, EMG, and PPG); communication (voice and email); individual personality and subjective team dynamics responses were collected and related to task performance. Initial analyses found that physiological measures can be used to identify transient stress, predict performance, and reflect subjective workload. Muscle tension and respiration were the most robust predictors. Not only the level of arousal but its variability during engagement in the task is important to consider. In general, less variability was found to be associated with higher levels of performance. Individuals scoring high on specific personality characteristics responded differently to task stress.

  10. Prenatal stressors in rodents: Effects on behavior

    Directory of Open Access Journals (Sweden)

    Marta Weinstock

    2017-02-01

    Full Text Available The current review focuses on studies in rodents published since 2008 and explores possible reasons for any differences they report in the effects of gestational stress on various types of behavior in the offspring. An abundance of experimental data shows that different maternal stressors in rodents can replicate some of the abnormalities in offspring behavior observed in humans. These include, anxiety, in juvenile and adult rats and mice, assessed in the elevated plus maze and open field tests and depression, detected in the forced swim and sucrose-preference tests. Deficits were reported in social interaction that is suggestive of pathology associated with schizophrenia, and in spatial learning and memory in adult rats in the Morris water maze test, but in most studies only males were tested. There were too few studies on the novel object recognition test at different inter-trial intervals to enable a conclusion about the effect of prenatal stress and whether any deficits are more prevalent in males. Among hippocampal glutamate receptors, NR2B was the only subtype consistently reduced in association with learning deficits. However, like in humans with schizophrenia and depression, prenatal stress lowered hippocampal levels of BDNF, which were closely correlated with decreases in hippocampal long-term potentiation. In mice, down-regulation of BDNF appeared to occur through the action of gene-methylating enzymes that are already increased above controls in prenatally-stressed neonates. In conclusion, the data obtained so far from experiments in rodents lend support to a physiological basis for the neurodevelopmental hypothesis of schizophrenia and depression.

  11. Gulf of Mexico Ecosystem Status Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Gulf of Mexico is one of the most ecologically and economically valuable marine ecosystems in the world and is affected by a variety of natural and anthropogenic...

  12. Tools and perspectives for assessing chemical mixtures and multiple stressors

    DEFF Research Database (Denmark)

    Løkke, Hans; Ragas, Ad M. J.; Holmstrup, Martin

    2013-01-01

    The present paper summarizes the most important insights and findings of the EU NoMiracle project with a focus on (1) risk assessment of chemical mixtures, (2) combinations of chemical and natural stressors, and (3) the receptor-oriented approach in cumulative risk assessment. The project aimed...... is suggested. The results are discussed in the light of recent developments in risk assessment of mixtures and multiple stressors....

  13. Integrated presentation of ecological risk from multiple stressors

    OpenAIRE

    Goussen, Benoit Regis Marc; Price, Oliver R.; Rendal, Cecilie; Ashauer, Roman

    2016-01-01

    Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing ...

  14. Climate change adaptation and mitigation options a guide for natural resource managers in southern forest ecosystems

    Science.gov (United States)

    James M. Vose; Kier D. Klepzig

    2014-01-01

    The rapid pace of climate change and its direct and indirect effects on forest ecosystems present a pressing need for better scientific understanding and the development of new science-management partnerships. Understanding the effects of stressors and disturbances (including climatic variability), and developing and testing science-based management options to deal...

  15. Global topics and novel approaches in the study of air pollution, climate change and forest ecosystems

    Science.gov (United States)

    P. Sicard; A. Augustaitis; S. Belyazid; C. Calfapietra; A. De Marco; Mark E. Fenn; Andrzej Bytnerowicz; Nancy Grulke; S. He; R. Matyssek; Y. Serengil; G. Wieser; E. Paoletti

    2016-01-01

    Research directions from the 27th conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems (2015) reflect knowledge advancements about (i) Mechanistic bases of tree responses to multiple climate and pollution stressors, in particular the interaction of ozone (O3) with nitrogen (N) deposition and drought; (ii)...

  16. Association between work role stressors and sleep quality.

    Science.gov (United States)

    Iwasaki, S; Deguchi, Y; Inoue, K

    2018-05-17

    Work-related stressors are associated with low sleep quality. However, few studies have reported an association between role stressors and sleep quality. To elucidate the association between role stressors (including role conflict and ambiguity) and sleep quality. Cross-sectional study of daytime workers whose sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Work-related stressors, including role stressors, were assessed using the Generic Job Stress Questionnaire (GJSQ). The association between sleep quality and work-related stressors was investigated by logistic regression analysis. A total of 243 participants completed questionnaires were received (response rate 71%); 86 participants reported poor sleep quality, based on a global PSQI score ≥6. Multivariable logistic regression analysis revealed that higher role ambiguity was associated with global PSQI scores ≥6, and that role conflict was significantly associated with sleep problems, including sleep disturbance and daytime dysfunction. These results suggest that high role stress is associated with low sleep quality, and that this association should be considered an important determinant of the health of workers.

  17. The organisational stressors encountered by athletes with a disability.

    Science.gov (United States)

    Arnold, Rachel; Wagstaff, Christopher R D; Steadman, Lauren; Pratt, Yasmin

    2017-06-01

    Organisational stressors have been found to be prevalent and problematic for sport performers, with research identifying demographic differences in the stressors encountered. Nevertheless, extant sport psychology research on the topic of stress has generally focused on able-bodied athletes; whilst that which has been conducted on performers with a disability has typically recruited relatively small samples to explore a narrow selection of organisational stressors, or examined other components of the stress process. The purpose of the present study was to explore the various organisational stressors that athletes with a disability encounter. The sample comprised 18 elite athletes with a disability (10 male, 8 female) who had a classified disability and experience of competing at a major championships in their sport (e.g., Paralympic Games, World Championships). Participants took part in a semi-structured interview which was analysed by drawing from grounded theory procedures. A total of 316 organisational stressors were identified, which were abstracted into 31 concepts and four, previously conceptualised, exploratory schemes: leadership and personnel issues, cultural and team issues, logistical and environmental issues, and performance and personal issues. This study not only provides the first illustration of the prevalence of organisational stressors for athletes with a disability, but also significantly points to salient similarities and distinct differences between the stress experiences of performers with and without a disability.

  18. Risk and markets for ecosystem services.

    Science.gov (United States)

    Bendor, Todd K; Riggsbee, J Adam; Doyle, Martin

    2011-12-15

    Market-based environmental regulations (e.g., cap and trade, "payments for ecosystem services") are increasingly common. However, few detailed studies of operating ecosystem markets have lent understanding to how such policies affect incentive structures for improving environmental quality. The largest U.S. market stems from the Clean Water Act provisions requiring ecosystem restoration to offset aquatic ecosystems damaged during development. We describe and test how variations in the rules governing this ecosystem market shift risk between regulators and entrepreneurs to promote ecological restoration. We analyze extensive national scale data to assess how two critical aspects of market structure - (a) the geographic scale of markets and (b) policies dictating the release of credits - affect the willingness of entrepreneurs to enter specific markets and produce credits. We find no discernible relationship between policies attempting to ease market entry and either the number of individual producers or total credits produced. Rather, market entry is primarily related to regional geography (the prevalence of aquatic ecosystems) and regional economic growth. Any improvements to policies governing ecosystem markets require explicit evaluation of the interplay between policy and risk elements affecting both regulators and entrepreneurial credit providers. Our findings extend to emerging, regulated ecosystem markets, including proposed carbon offset mechanisms, biodiversity banking, and water quality trading programs.

  19. Ecosystem stress response : understanding effects on the benthic invertebrate community of Alberta oil-sands wetlands

    International Nuclear Information System (INIS)

    Wytrykush, C.M.; Ciborowski, J.J.H.

    2003-01-01

    The environmental stress response of invertebrates was examined using wetlands in the Alberta oil-sands region as a model. Wetlands in this region occur naturally or they have been affected by oil-sands mining process materials such as mine-tailings, or saline process water. These materials can be toxic to aquatic organisms due to their high concentrations of sulphate ions, ammonia, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids. Wetlands are classified as either young or mature, and as having low or high sediment organic content. This study examined food web dynamics and structure in wetlands using stable isotopes to determine the effects of stress on ecological communities. Primary and secondary production in the wetlands was measured along with invertebrate diversity in order to determine a relationship. The maximum trophic position was determined using stable carbon and nitrogen isotopes to indicate food chain length which is influenced by energetic constraints, ecosystem size and stressors. The study quantifies the dynamics of vital links between the responses to environmental pressures in aquatic systems and the effects on terrestrial ecosystems

  20. Measuring Entrepreneurial Ecosystems

    OpenAIRE

    Stam, F.C.

    2017-01-01

    How can entrepreneurial ecosystems and productive entrepreneurship can be traced empirically and how is entrepreneurship related to entrepreneurial ecosystems. The analyses in this chapter show the value of taking a systems view on the context of entrepreneurship. We measure entrepreneurial ecosystem elements and use these to compose an entrepreneurial ecosystem index. Next, we measure the output of entrepreneurial ecosystems with different indicators of high-growth firms. We use the 12 provi...

  1. Mapping Ecosystem Services

    OpenAIRE

    Georgiev,Teodor; Burkhard,Benjamin; Maes,Joachim

    2017-01-01

    Ecosystem services are the contributions of ecosystem structure and function (in combination with other inputs) to human well-being. That means, humankind is strongly dependent on well-functioning ecosystems and natural capital that are the base for a constant flow of ecosystem services from nature to society. Therefore ecosystem services have the potential to become a major tool for policy and decision making on global, national, regional and local scales. Possible applications are manifold:...

  2. The role of anger and ongoing stressors in mental health following a natural disaster.

    Science.gov (United States)

    Forbes, David; Alkemade, Nathan; Waters, Elizabeth; Gibbs, Lisa; Gallagher, Colin; Pattison, Phillipa; Lusher, Dean; MacDougall, Colin; Harms, Louise; Block, Karen; Snowdon, Elyse; Kellet, Connie; Sinnott, Vikki; Ireton, Greg; Richardson, John; Bryant, Richard A

    2015-08-01

    Research has established the mental health sequelae following disaster, with studies now focused on understanding factors that mediate these outcomes. This study focused on anger, alcohol, subsequent life stressors and traumatic events as mediators in the development of mental health disorders following the 2009 Black Saturday Bushfires, Australia's worst natural disaster in over 100 years. This study examined data from 1017 (M = 404, F = 613) adult residents across 25 communities differentially affected by the fires and participating in the Beyond Bushfires research study. Data included measures of fire exposure, posttraumatic stress disorder, depression, alcohol abuse, anger and subsequent major life stressors and traumatic events. Structural equation modeling assessed the influence of factors mediating the effects of fire exposure on mental health outcomes. Three mediation models were tested. The final model recorded excellent fit and observed a direct relationship between disaster exposure and mental health outcomes (b = .192, p disaster exposure and development of mental health problems. The findings have significant implications for the assessment of anger post disaster, the provision of targeted anger-focused interventions and delivery of government and community assistance and support in addressing ongoing stressors in the post-disaster context to minimize subsequent mental health consequences. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  3. Cultural Stressors and the Hopelessness Model of Depressive Symptoms in Latino Adolescents

    Science.gov (United States)

    Stein, Gabriela L.; Gonzalez, Laura M.; Huq, Nadia

    2012-01-01

    Depressive symptoms in Latino youth have been related to both culturally-universal and culturally-based stressors. However, few studies have examined the unique contributions of culturally-based stressors above and beyond other types of stressors. Moreover, no past studies with Latinos have examined the role of culturally-based stressors within a…

  4. Gender and Personality Differences in Response to Social Stressors in Great Tits (Parus major.

    Directory of Open Access Journals (Sweden)

    Esther van der Meer

    Full Text Available In response to stressors, animals can increase the activity of the hypothalamic-pituitary-adrenocortical axis, resulting in elevated glucocorticoid concentrations. An increase in glucocorticoids results in an increase in heterophils and a decrease in lymphocytes, which ratio (H/L-ratio is an indicator of stress in birds. The physiological response to a stressor can depend on individual characteristics, like dominance rank, sex and personality. Although the isolated effects of these characteristics on the response to a stressor have been well studied, little is known about the response in relation to a combination of these characteristics. In this study we investigate the relationship between social stress, dominance rank, sex and exploratory behaviour as a validated operational measure of personality in great tits (Parus major. Great tits show consistent individual differences in behaviour and physiology in response to stressors, and exploratory behaviour can be classified as fast or slow exploring. We group-housed four birds, two fast and two slow explorers, of the same sex that were previously singly housed, in an aviary and compared the H/L-ratio, lymphocyte and heterophil count before and after group housing. After experiencing the social context all birds increased their H/L-ratio and heterophil count. Females showed a stronger increase in H/L-ratio and heterophil count than males, which seemed to be related to a higher number of agonistic interactions compared to males. Dominance rank and exploration type did not affect the H/L-ratio or heterophil count. Contrary to our expectations, all birds increased their lymphocyte count. However, this increase was slower for fast than for slow explorers. Our study suggests that personality and sex related differences, but not dominance rank, are associated with changes in an individual's physiological response due to a social context.

  5. Forecasting the relative influence of environmental and anthropogenic stressors on polar bears

    Science.gov (United States)

    Atwood, Todd C.; Marcot, Bruce G.; Douglas, David C.; Amstrup, Steven C.; Rode, Karyn D.; Durner, George M.; Bromaghin, Jeffrey F.

    2016-01-01

    Effective conservation planning requires understanding and ranking threats to wildlife populations. We developed a Bayesian network model to evaluate the relative influence of environmental and anthropogenic stressors, and their mitigation, on the persistence of polar bears (Ursus maritimus). Overall sea ice conditions, affected by rising global temperatures, were the most influential determinant of population outcomes. Accordingly, unabated rise in atmospheric greenhouse gas (GHG) concentrations was the dominant influence leading to worsened population outcomes, with polar bears in three of four ecoregions reaching a dominant probability of decreased or greatly decreased by the latter part of this century. Stabilization of atmospheric GHG concentrations by mid-century delayed the greatly reduced state by ≈25 yr in two ecoregions. Prompt and aggressive mitigation of emissions reduced the probability of any regional population becoming greatly reduced by up to 25%. Marine prey availability, linked closely to sea ice trend, had slightly less influence on outcome state than sea ice availability itself. Reduced mortality from hunting and defense of life and property interactions resulted in modest declines in the probability of a decreased or greatly decreased population outcome. Minimizing other stressors such as trans-Arctic shipping, oil and gas exploration, and contaminants had a negligible effect on polar bear outcomes, although the model was not well-informed with respect to the potential influence of these stressors. Adverse consequences of loss of sea ice habitat became more pronounced as the summer ice-free period lengthened beyond four months, which could occur in most of the Arctic basin after mid-century if GHG emissions are not promptly reduced. Long-term conservation of polar bears would be best supported by holding global mean temperature to ≤ 2°C above preindustrial levels. Until further sea ice loss is stopped, management of other stressors may

  6. Effects of Multiple Stressors on Red Abalone (Haliotis rufescens) Fertilization Success

    Science.gov (United States)

    Boch, C. A.; Aalto, E.; De Leo, G.; Litvin, S.; Lovera, C.; Micheli, F.; Woodson, C. B.; Monismith, S. G.; Barry, J. P.

    2016-02-01

    Acidification, hypoxia, and ocean warming are escalating threats in the world's coastal waters, with potentially severe consequences for marine life and ocean-based economies. In particular, eastern boundary current ecosystems, including the California Current Large Marine Ecosystem (CCLME), are experiencing large-scale declines in pH and dissolved oxygen (DO)—with the latter linked to changes in thermal stratification and shoaling of the oxygen minimum zone. To examine the consequences of ocean acidification and other climate-related changes in oceanographic conditions on nearshore marine populations within the CCLME, we are assessing the potential effects of current and future upwelling-type conditions on the population dynamics of the red abalone (Haliotis rufescens), with a focus on sensitive early life history phases (e.g., fertilization, larval development, and juvenile growth and survival) expected to be important determinants of population dynamics. Here, we present the first experimental results on the impacts of combined exposures of low pH and low DO on abalone fertilization success. Our results show that abalone fertilization success is significantly reduced when the gametes are exposed to a decrease in seawater pH from 8.0 to 7.2. Furthermore, low pH in combination with hypoxic exposure—e.g., a decrease in dissolved oxygen from 6 mg/L DO to 1 mg/L DO—does not further decrease fertilization rates, suggesting a lack of synergistic or additive effects of these multiple stressors on the reduction of fertilization success. Although the focus of this study is to characterize the effects of multiple stressors on the early life history of abalone, the implications of these results are expected to be relevant for a variety of marine taxa with similar reproductive modes.

  7. A comparison of course-related stressors in undergraduate problem-based learning (PBL versus non-PBL medical programmes

    Directory of Open Access Journals (Sweden)

    Ross Elizabeth E

    2009-09-01

    Full Text Available Abstract Background Medical students report high levels of stress related to their medical training as well as to other personal and financial factors. The aim of this study is to investigate whether there are differences in course-related stressors reported by medical students on undergraduate problem-based learning (PBL and non-PBL programmes in the UK. Method A cross-sectional study of second-year medical students in two UK medical schools (one PBL and one non-PBL programme was conducted. A 16-question self-report questionnaire, derived from the Perceived Medical Student Stress Scale and the Higher Education Stress Inventory, was used to measure course-related stressors. Following univariate analysis of each stressor between groups, multivariate logistic regression was used to determine which stressors were the best predictors of each course type, while controlling for socio-demographic differences between the groups. Results A total of 280 students responded. Compared to the non-PBL students (N = 197, the PBL students (N = 83 were significantly more likely to agree that: they did not know what the faculty expected of them (Odds Ratio (OR = 0.38, p = 0.03; there were too many small group sessions facilitated only by students resulting in an unclear curriculum (OR = 0.04, p Conclusion There are significant differences in the perceived course-related stressors affecting medical students on PBL and non-PBL programmes. Course designers and student support services should therefore tailor their work to minimise, or help students cope with, the specific stressors on each course type to ensure optimum learning and wellbeing among our future doctors.

  8. A comparison of course-related stressors in undergraduate problem-based learning (PBL) versus non-PBL medical programmes.

    Science.gov (United States)

    Lewis, Alexander D; Menezes, Darryl A Braganza; McDermott, Helen E; Hibbert, Louise J; Brennan, Sarah-Louise; Ross, Elizabeth E; Jones, Lisa A

    2009-09-13

    Medical students report high levels of stress related to their medical training as well as to other personal and financial factors. The aim of this study is to investigate whether there are differences in course-related stressors reported by medical students on undergraduate problem-based learning (PBL) and non-PBL programmes in the UK. A cross-sectional study of second-year medical students in two UK medical schools (one PBL and one non-PBL programme) was conducted. A 16-question self-report questionnaire, derived from the Perceived Medical Student Stress Scale and the Higher Education Stress Inventory, was used to measure course-related stressors. Following univariate analysis of each stressor between groups, multivariate logistic regression was used to determine which stressors were the best predictors of each course type, while controlling for socio-demographic differences between the groups. A total of 280 students responded. Compared to the non-PBL students (N = 197), the PBL students (N = 83) were significantly more likely to agree that: they did not know what the faculty expected of them (Odds Ratio (OR) = 0.38, p = 0.03); there were too many small group sessions facilitated only by students resulting in an unclear curriculum (OR = 0.04, p academic subjects of interest (OR = 0.40, p = 0.02). They were significantly more likely to disagree that: there was a lack of encouragement from teachers (OR = 3.11, p = 0.02); and that the medical course fostered a sense of anonymity and feelings of isolation amongst students (OR = 3.42, p = 0.008). There are significant differences in the perceived course-related stressors affecting medical students on PBL and non-PBL programmes. Course designers and student support services should therefore tailor their work to minimise, or help students cope with, the specific stressors on each course type to ensure optimum learning and wellbeing among our future doctors.

  9. Ecological risk assessment of mixtures of radiological and chemical stressors: Methodology to implement an msPAF approach

    International Nuclear Information System (INIS)

    Beaumelle, Léa; Della Vedova, Claire; Beaugelin-Seiller, Karine; Garnier-Laplace, Jacqueline; Gilbin, Rodolphe

    2017-01-01

    A main challenge in ecological risk assessment is to account for the impact of multiple stressors. Nuclear facilities can release both radiological and chemical stressors in the environment. This study is the first to apply species sensitivity distribution (SSD) combined with mixture models (concentration addition (CA) and independent action (IA)) to derive an integrated proxy of the ecological impact of combined radiological and chemical stressors: msPAF (multisubstance potentially affected fraction of species). The approach was tested on the routine liquid effluents from nuclear power plants that contain both radioactive and stable chemicals. The SSD of ionising radiation was significantly flatter than the SSD of 8 stable chemicals (namely Cr, Cu, Ni, Pb, Zn, B, chlorides and sulphates). This difference in shape had strong implications for the selection of the appropriate mixture model: contrarily to the general expectations the IA model gave more conservative (higher msPAF) results than the CA model. The msPAF approach was further used to rank the relative potential impact of radiological versus chemical stressors. - Highlights: • msPAF methodology was applied on mixtures of radiological and chemical stressors. • A consistent set of chronic SSDs was collected for ionising radiation and 8 stable chemicals. • The SSD of ionising radiation had lower steepness than the SSD of stable chemicals. • This resulted in higher msPAF values based on the IA than on the CA mixture model. - The msPAF approach combining SSD and mixture models was used for the first time on mixtures of radiological and chemical stressors.

  10. A conceptual model for the analysis of multi-stressors in linked groundwater-surface water systems.

    Science.gov (United States)

    Kaandorp, Vince P; Molina-Navarro, Eugenio; Andersen, Hans E; Bloomfield, John P; Kuijper, Martina J M; de Louw, Perry G B

    2018-06-15

    Groundwater and surface water are often closely coupled and are both under the influence of multiple stressors. Stressed groundwater systems may lead to a poor ecological status of surface waters but to date no conceptual framework to analyse linked multi-stressed groundwater - surface water systems has been developed. In this paper, a framework is proposed showing the effect of groundwater on surface waters in multiple stressed systems. This framework will be illustrated by applying it to four European catchments, the Odense, Denmark, the Regge and Dinkel, Netherlands, and the Thames, UK, and by assessing its utility in analysing the propagation or buffering of multi-stressors through groundwater to surface waters in these catchments. It is shown that groundwater affects surface water flow, nutrients and temperature, and can both propagate stressors towards surface waters and buffer the effect of stressors in space and time. The effect of groundwater on drivers and states depends on catchment characteristics, stressor combinations, scale and management practises. The proposed framework shows how groundwater in lowland catchments acts as a bridge between stressors and their effects within surface waters. It shows water managers how their management areas might be influenced by groundwater, and helps them to include this important, but often overlooked part of the water cycle in their basin management plans. The analysis of the study catchments also revealed a lack of data on the temperature of both groundwater and surface water, while it is an important parameter considering future climate warming. Copyright © 2018. Published by Elsevier B.V.

  11. Investigating the Relationships among Stressors, Stress Level, and Mental Symptoms for Infertile Patients: A Structural Equation Modeling Approach.

    Directory of Open Access Journals (Sweden)

    Jong-Yi Wang

    Full Text Available Patients with infertility are a high risk group in depression and anxiety. However, an existing theoretically and empirically validated model of stressors, stress, and mental symptoms specific for infertile patients is still a void. This study aimed to determine the related factors and their relational structures that affect the level of depressive and anxiety symptoms among infertile patients.A cross-sectional sample of 400 infertility outpatients seeking reproduction treatments in three teaching hospitals across Taiwan participated in the structured questionnaire survey in 2011. The hypothesized model comprising 10 latent variables was tested by Structural Equation Modeling using AMOS 17.Goodness-of-fit indexes, including χ2/DF = 1.871, PGFI = 0.746, PNFI = 0.764, and others, confirmed the modified model fit the data well. Marital stressor, importance of children, guilt-and-blame, and social stressor showed a direct effect on perceived stress. Instead of being a factor of stress, social support was directly and positively related to self-esteem. Perceived stress and self-esteem were the two major mediators for the relationships between stressors and mental symptoms. Increase in social support and self-esteem led to decrease in mental symptoms among the infertile patients.The relational structures were identified and named as the Stressors Stress Symptoms Model, clinically applied to predict anxiety and depression from various stressors. Assessing sources and level of infertility-related stress and implementing culturally-sensitive counseling with an emphasis on positive personal value may assist in preventing the severity of depression and anxiety.

  12. Investigating the Relationships among Stressors, Stress Level, and Mental Symptoms for Infertile Patients: A Structural Equation Modeling Approach.

    Science.gov (United States)

    Wang, Jong-Yi; Li, Yi-Shan; Chen, Jen-De; Liang, Wen-Miin; Yang, Tung-Chuan; Lee, Young-Chang; Wang, Chia-Woei

    2015-01-01

    Patients with infertility are a high risk group in depression and anxiety. However, an existing theoretically and empirically validated model of stressors, stress, and mental symptoms specific for infertile patients is still a void. This study aimed to determine the related factors and their relational structures that affect the level of depressive and anxiety symptoms among infertile patients. A cross-sectional sample of 400 infertility outpatients seeking reproduction treatments in three teaching hospitals across Taiwan participated in the structured questionnaire survey in 2011. The hypothesized model comprising 10 latent variables was tested by Structural Equation Modeling using AMOS 17. Goodness-of-fit indexes, including χ2/DF = 1.871, PGFI = 0.746, PNFI = 0.764, and others, confirmed the modified model fit the data well. Marital stressor, importance of children, guilt-and-blame, and social stressor showed a direct effect on perceived stress. Instead of being a factor of stress, social support was directly and positively related to self-esteem. Perceived stress and self-esteem were the two major mediators for the relationships between stressors and mental symptoms. Increase in social support and self-esteem led to decrease in mental symptoms among the infertile patients. The relational structures were identified and named as the Stressors Stress Symptoms Model, clinically applied to predict anxiety and depression from various stressors. Assessing sources and level of infertility-related stress and implementing culturally-sensitive counseling with an emphasis on positive personal value may assist in preventing the severity of depression and anxiety.

  13. The role of Dynamic Energy Budget theory in predictive modeling of stressor impacts on ecological systems. Comment on: ;Physics of metabolic organization; by Marko Jusup et al.

    Science.gov (United States)

    Galic, Nika; Forbes, Valery E.

    2017-03-01

    Human activities have been modifying ecosystems for centuries, from pressures on wild populations we harvest to modifying habitats through urbanization and agricultural activities. Changes in global climate patterns are adding another layer of, often unpredictable, perturbations to ecosystems on which we rely for life support [1,2]. To ensure the sustainability of ecosystem services, especially at this point in time when the human population is estimated to grow by another 2 billion by 2050 [3], we need to predict possible consequences of our actions and suggest relevant solutions [4,5]. We face several challenges when estimating adverse impacts of our actions on ecosystems. We describe these in the context of ecological risk assessment of chemicals. Firstly, when attempting to assess risk from exposure to chemicals, we base our decisions on a very limited number of species that are easily cultured and kept in the lab. We assume that preventing risk to these species will also protect all of the untested species present in natural ecosystems [6]. Secondly, although we know that chemicals interact with other stressors in the field, the number of stressors that we can test is limited due to logistical and ethical reasons. Similarly, empirical approaches are limited in both spatial and temporal scale due to logistical, financial and ethical reasons [7,8]. To bypass these challenges, we can develop ecological models that integrate relevant life history and other information and make testable predictions across relevant spatial and temporal scales [8-10].

  14. Transformation of Digital Ecosystems

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Hedman, Jonas

    2014-01-01

    the Digital Ecosystem Technology Transformation (DETT) framework for explaining technology-based transformation of digital ecosystems by integrating theories of business and technology ecosystems. The framework depicts ecosystem transformation as distributed and emergent from micro-, meso-, and macro- level......In digital ecosystems, the fusion relation between business and technology means that the decision of technical compatibility of the offering is also the decision of how to position the firm relative to the coopetive relations that characterize business ecosystems. In this article we develop...... coopetition. The DETT framework consists an alternative to the existing explanations of digital ecosystem transformation as the rational management of one central actor balancing ecosystem tensions. We illustrate the use of the framework by a case study of transformation in the digital payment ecosystem...

  15. Ecosystem degradation in India

    International Nuclear Information System (INIS)

    Sinha, B.N.

    1990-01-01

    Environmental and ecosystem studies have assumed greater relevance in the last decade of the twentieth century than even before. The urban settlements are becoming over-crowded and industries are increasingly polluting the air, water and sound in our larger metropolises. Degradation of different types of ecosystem are discussed in this book, Ecosystem Degradation in India. The book has been divided into seven chapters: Introduction, Coastal and Delta Ecosystem, River Basin Ecosystem, Mountain Ecosystem, Forest Ecosystem, Urban Ecosystem and the last chapter deals with the Environmental Problems and Planning. In the introduction the environmental and ecosystem degradation problems in India is highlighted as a whole while in other chapters mostly case studies by experts who know their respective terrain very intimately are included. The case study papers cover most part of India and deal with local problems, stretching from east coast to west coast and from Kashmir to Kanyakumari. (author)

  16. Eco-systems biology-From the gene to the stream

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, Colin

    2010-01-01

    This review considers the implications for environmental health and ecosystem sustainability, of new developments in radiobiology and ecotoxicology. Specifically it considers how the non-targeted effects of low doses of radiation, which are currently being scrutinized experimentally, not only mirror similar effects from low doses of chemical stressors but may actually lead to unpredictable emergent effects at higher hierarchical levels. The position is argued that non-targeted effects are mechanistically important in coordinating phased hierarchical transitions (i.e. transitions which occur in a regulated sequence). The field of multiple stressors (both radiation and chemical) is highly complex and agents can interact in an additive, antagonist or synergistic manner. The outcome following low dose multiple stressor exposure also is impacted by the context in which the stressors are received, perceived or communicated by the organism or tissue. Modern biology has given us very sensitive methods to examine changes following stressor interaction with biological systems at several levels of organization but the translation of these observations to ultimate risk remains difficult to resolve. Since multiple stressor exposure is the norm in the environment, it is essential to move away from single stressor-based protection and to develop tools, including legal instruments, which will enable us to use response-based risk assessment. Radiation protection in the context of multiple stressors includes consideration of humans and non-humans as separate groups requiring separate assessment frameworks. This is because for humans, individual survival and prevention of cancer are paramount but for animals, it is considered sufficient to protect populations and cancer is not of concern. The need to revisit this position is discussed not only from the environmental perspective but also from the human health perspective because the importance of 'pollution' (a generic term for

  17. The impacts of multiple stressors to model ecological structures

    International Nuclear Information System (INIS)

    Landis, W.G.; Kelly, S.A.; Markiewicz, A.J.; Matthews, R.A.; Matthews, G.B.

    1995-01-01

    The basis of the community conditioning hypothesis is that ecological structures are the result of their unique etiology. Systems that have been exposed to a variety of stressors should reflect this history. The authors how conducted a series of microcosm experiments that can compare the effects of multiple stressors upon community dynamics. The microcosm protocols are derived from the Standardized Aquatic Microcosm (SAM) and have Lemma and additional protozoan species. Two multiple stressor experiments have been conducted. In an extended length SAM (ELSAM), two of four treatments were dosed with the turbine fuel JP-8 one week into the experiment. Two treatments were later exposed to the heat stress, one that had received jet fuel and one that had not. Similarly, an ELSAM was conducted with the second stressor being the further addition of JP-8 replacing the heat shock. Biological, physical and chemical data were analyzed with multivariate techniques including nonmetric clustering and association analysis. Space-time worms and phase diagrams were also employed to ascertain the dynamic relationships of variables identified as important by the multivariate techniques. The experiments do not result in a simple additive linear response to the additional stressor. Examination of the relative population dynamics reveal alterations in trajectories that suggest treatment related effects. As in previous single stressor experiments, recovery does not occur even after extended experimental periods. The authors are now attempting to measure the resulting trajectories, changes in similarity vectors and overall dynamics. However, community conditioning does appear to be an important framework in understanding systems with a heterogeneous array of stressors

  18. A single exposure to severe stressors causes long-term desensitisation of the physiological response to the homotypic stressor.

    Science.gov (United States)

    Armario, Antonio; Vallès, Astrid; Dal-Zotto, Silvina; Márquez, Cristina; Belda, Xavier

    2004-09-01

    Although some laboratories have reported that a single session of stress is able to induce a long-lasting sensitisation of the hypothalamic-pituitary-adrenal (HPA) response to further exposures to stress, we have found that a single exposure to severe emotional (immobilisation, restraint or shock) or systemic (endotoxin) stressors reduces the responsiveness of the HPA to the same, but not to a novel (heterotypic), stressor, in which case a slight sensitisation was observed. Long-term desensitisation has been found to reduce not only secretion of peripheral HPA hormones (ACTH and corticosterone), but also to reduce responses of central components of the HPA axis (c-fos and CRF gene expression at the level of the paraventricular nucleus of the hypothalamus, PVN). In addition, desensitisation also applies to the impact of the stressor on food intake and, probably, to stress-induced hyperglycaemia. The development of long-term desensitisation of the HPA axis does not appear to be a universal consequence of exposure to severe stressors as it was not observed in response to insulin-induced hypoglycaemia. Whether or not the development of long-term effects of stress depend on the specific pathways activated by particular stressors remains to be tested. The observed desensitisation of the HPA axis in response to the homotypic stressor shows two special features which makes it difficult to be interpreted in terms of an habituation-like process: (a) the effect increased with time (days to weeks) elapsed between the first and second exposure to the stressor, suggesting a progressive maturational process; and (b) the stronger the stressor the greater the long-term desensitisation. Therefore, it is possible that desensitisation of the HPA axis is the sum of two different phenomena: long-term effects and habituation-like processes. The contribution of the former may be more relevant with severe stressors and longer inter-stress intervals, and that of the latter with mild

  19. Fluvial gravel stabilization by net-spinning Hydropsychid caddisflies: exploring the magnitude and geographic scope of ecosystem engineering effect and evaluating resistance to anthropogenic stresses

    Science.gov (United States)

    Daniels, M.; Albertson, L.; Sklar, L. S.; Tumolo, B.; Mclaughlin, M. K.

    2017-12-01

    Several studies have demonstrated the substantial effects that organisms can have on earth surface processes. Known as ecosystem engineers, in streams these organisms maintain, modify, or create physical habitat structure by influencing fluvial processes such as gravel movement, fine sediment deposition and bank erosion. However, the ecology of ecosystem engineers and the magnitude of ecosystem engineering effects in a world increasingly influence by anthropogenically-driven changes is not well understood. Here we present a synthesis of research findings on the potential gravel stabilization effects of Hydropsychid caddisflies, a globally distributed group of net-spinning insects that live in the benthic substrate of most freshwater streams. Hydropsychid caddisflies act as ecosystem engineers because these silk structures can fundamentally alter sediment transport conditions, including sediment stability and flow currents. The silk nets spun by these insects attach gravel grains to one another, increasing the shear stress required to initiate grain entrainment. In a series of independent laboratory experiments, we investigate the gravel size fractions most affected by these silk attachments. We also investigate the role of anthropogenic environmental stresses on ecosystem engineering potential by assessing the impact of two common stressors, high fine sediment loads and stream drying, on silk structures. Finally, an extensive field survey of grain size and Hydropsychid caddisfly population densities informs a watershed-scale network model of Hydropsychid caddisfly gravel stabilizing potential. Our findings provide some of the first evidence that caddisfly silk may be a biological structure that is resilient to various forms of human-mediated stress and that the effects of animal ecosystem engineers are underappreciated as an agent of resistance and recovery for aquatic communities experiencing changes in sediment loads and hydrologic regimes.

  20. Invertebrates, ecosystem services and climate change.

    Science.gov (United States)

    Prather, Chelse M; Pelini, Shannon L; Laws, Angela; Rivest, Emily; Woltz, Megan; Bloch, Christopher P; Del Toro, Israel; Ho, Chuan-Kai; Kominoski, John; Newbold, T A Scott; Parsons, Sheena; Joern, A

    2013-05-01

    The sustainability of ecosystem services depends on a firm understanding of both how organisms provide these services to humans and how these organisms will be altered with a changing climate. Unquestionably a dominant feature of most ecosystems, invertebrates affect many ecosystem services and are also highly responsive to climate change. However, there is still a basic lack of understanding of the direct and indirect paths by which invertebrates influence ecosystem services, as well as how climate change will affect those ecosystem services by altering invertebrate populations. This indicates a lack of communication and collaboration among scientists researching ecosystem services and climate change effects on invertebrates, and land managers and researchers from other disciplines, which becomes obvious when systematically reviewing the literature relevant to invertebrates, ecosystem services, and climate change. To address this issue, we review how invertebrates respond to climate change. We then review how invertebrates both positively and negatively influence ecosystem services. Lastly, we provide some critical future directions for research needs, and suggest ways in which managers, scientists and other researchers may collaborate to tackle the complex issue of sustaining invertebrate-mediated services under a changing climate. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

  1. Trade and the governance of ecosystem services

    International Nuclear Information System (INIS)

    Norgaard, Richard B.; Jin, Ling

    2008-01-01

    We work with a basic general equilibrium model of an economy with an industrial good and a rural good. Industrial good production results in pollution that affects the provision of ecosystem services and thereby the production of the rural good. The assignment of ecosystem rights to the industrial polluters or to the rural pollutees results in differential transaction costs that affect production possibilities between the two goods. Ecosystem rights are assigned to maximize social welfare. Over time, technological change and differences in income superiority affect the choice of the assignment of rights. Opening to trade affects the choice of the assignment of ecosystem rights depending on the nature of technological change, but the relative income superiority of goods no longer affects the assignment of ecosystem rights in a small economy. Thus, among other findings, we demonstrate that the phenomena known as the environmental Kuznets curve does not hold for the protection of ecosystem services in production, or production externalities generally, because trade separates consumption from production. (author)

  2. Trade and the governance of ecosystem services

    Energy Technology Data Exchange (ETDEWEB)

    Norgaard, Richard B.; Jin, Ling [Energy and Resources Group, University of California, Berkeley (United States)

    2008-07-15

    We work with a basic general equilibrium model of an economy with an industrial good and a rural good. Industrial good production results in pollution that affects the provision of ecosystem services and thereby the production of the rural good. The assignment of ecosystem rights to the industrial polluters or to the rural pollutees results in differential transaction costs that affect production possibilities between the two goods. Ecosystem rights are assigned to maximize social welfare. Over time, technological change and differences in income superiority affect the choice of the assignment of rights. Opening to trade affects the choice of the assignment of ecosystem rights depending on the nature of technological change, but the relative income superiority of goods no longer affects the assignment of ecosystem rights in a small economy. Thus, among other findings, we demonstrate that the phenomena known as the environmental Kuznets curve does not hold for the protection of ecosystem services in production, or production externalities generally, because trade separates consumption from production. (author)

  3. Development and Initial Validation of the Student Rating of Environmental Stressors Scale: Stressors Faced by Students in Accelerated High School Curricula

    Science.gov (United States)

    Suldo, Shannon M.; Dedrick, Robert F.; Shaunessy-Dedrick, Elizabeth; Roth, Rachel A.; Ferron, John

    2015-01-01

    High school students in accelerated curricula face stressors beyond typical adolescent developmental challenges. The Student Rating of Environmental Stressors Scale (StRESS) is a self-report measure of environmental stressors appropriate for students in Advanced Placement (AP) and International Baccalaureate (IB) courses. We developed the StRESS…

  4. Associations of financial stressors and physical intimate partner violence perpetration.

    Science.gov (United States)

    Schwab-Reese, Laura M; Peek-Asa, Corinne; Parker, Edith

    2016-12-01

    Contextual factors, such as exposure to stressors, may be antecedents to IPV perpetration. These contextual factors may be amenable to modification through intervention and prevention. However, few studies have examined specific contextual factors. To begin to address this gap, we examined the associations between financial stressors and three types of physical IPV perpetration. This analysis used data from Wave IV of The National Longitudinal Study of Adolescent to Adult Health. We used logistic regression to examine the associations of financial stressors and each type of IPV (minor, severe, causing injury), and multinomial logit regression to examine the associations of financial stressors and patterns of co-occurring types of IPV perpetration (only minor; only severe; minor and severe; minor, severe, and causing injury; compared with no perpetration). Fewer men perpetrated threats/minor physical IPV (6.7 %) or severe physical IPV (3.4 %) compared with women (11.4 % and 8.8 %, respectively). However, among physical IPV perpetrators, a higher percentage of men (32.0 %) than women (21.0 %) reported their partner was injured as a result of the IPV. In logistic regression models of each type of IPV perpetration, both the number of stressors experienced and several types of financial stressors were associated with perpetrating each type of IPV. Utilities nonpayment, housing nonpayment, food insecurity, and no phone service were associated with increased odds of perpetrating each form of IPV in adjusted analysis. Eviction was associated with perpetrating severe physical IPV but not threats/minor IPV or IPV causing injury. In multinomial logit regression comparing patterns of IPV perpetration to perpetrating no physical IPV, the relationships of financial stressors were less consistent. Food insecurity was associated with perpetrating only minor physical IPV. Comparatively, overall number of financial stressors and four types of financial stressors (utilities

  5. Integrated presentation of ecological risk from multiple stressors

    Science.gov (United States)

    Goussen, Benoit; Price, Oliver R.; Rendal, Cecilie; Ashauer, Roman

    2016-10-01

    Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing and interpreting prevalence plots as a quantitative prediction of risk. Key components include environmental scenarios that integrate exposure and ecology, and ecological modelling of relevant endpoints to assess the effect of a combination of stressors. Our illustrative results demonstrate the importance of regional differences in environmental conditions and the confounding interactions of stressors. Using this framework and prevalence plots provides a risk-based approach that combines risk assessment and risk management in a meaningful way and presents a truly mechanistic alternative to the threshold approach. Even whilst research continues to improve the underlying models and data, regulators and decision makers can already use the framework and prevalence plots. The integration of multiple stressors, environmental conditions and variability makes ERA more relevant and realistic.

  6. Work stressors and impaired sleep: rumination as a mediator.

    Science.gov (United States)

    Berset, Martial; Elfering, Achim; Lüthy, Stefan; Lüthi, Simon; Semmer, Norbert K

    2011-04-01

    An association between stress at work and impaired sleep is theoretically plausible and supported by empirical evidence. The current study's main aim was to investigate how the influence of stressors is carried over into the evening and the night. We assume that this relationship is mediated by perseverative cognitions. We tested this assumption in two cross-sectional samples with structural equation modeling, using bootstrapped standard errors to test for significance. Effort–reward imbalance and time pressure were used as stressors, and rumination as a measure for perseverative cognitions. Results show that the stressors are related to perseverative cognitions, and these are related to impaired sleep in both samples. Indirect effects are significant in both samples. With rumination controlled, direct effects of stressors on sleep are only significant in one out of four cases. Thus, there is full mediation in three out of four cases, and partial mediation in the fourth one. Our results underscore the notion that perseverative cognitions are crucial for transferring negative effects of work stressors into private life, including sleep, thus hindering individuals to successfully recover.

  7. A review of multiple stressor studies that include ionising radiation

    International Nuclear Information System (INIS)

    Vanhoudt, Nathalie; Vandenhove, Hildegarde; Real, Almudena; Bradshaw, Clare; Stark, Karolina

    2012-01-01

    Studies were reviewed that investigated the combined effects of ionising radiation and other stressors on non-human biota. The aim was to determine the state of research in this area of science, and determine if a review of the literature might permit a gross generalization as to whether the combined effects of multi-stressors and radiation are fundamentally additive, synergistic or antagonistic. A multiple stressor database was established for different organism groups. Information was collected on species, stressors applied and effects evaluated. Studies were mostly laboratory based and investigated two-component mixtures. Interactions declared positive occurred in 58% of the studies, while 26% found negative interactions. Interactions were dependent on dose/concentration, on organism's life stage and exposure time and differed among endpoints. Except for one study, none of the studies predicted combined effects following Concentration Addition or Independent Action, and hence, no justified conclusions can be made about synergism or antagonism. - This review on multiple stressor studies involving radiation, highlights that most experimental designs used did not allow to deduce the nature of the interactive effects.

  8. Demographic differences in sport performers' experiences of organizational stressors.

    Science.gov (United States)

    Arnold, R; Fletcher, D; Daniels, K

    2016-03-01

    Organizational stressors are particularly prevalent across sport performers' experiences and can influence their performance, health, and well-being. Research has been conducted to identify which organizational stressors are encountered by sport performers, but little is known about how these experiences vary from athlete to athlete. The purpose of this study was to examine if the frequency, intensity, and duration of the organizational stressors that sport performers encounter vary as a function of gender, sport type, and performance level. Participants (n = 1277) completed the Organizational Stressor Indicator for Sport Performers (OSI-SP; Arnold et al., 2013), and the resultant data were analyzed using multivariate analyses of covariance. The findings show that demographic differences are apparent in the dimensions of the goals and development, logistics and operations, team and culture, coaching, and selection organizational stressors that sport performers encounter. More specifically, significant differences were found between males and females, between team and individual-based performers, and between performers competing at national or international, regional or university, and county or club levels. These findings have important implications for theory and research on organizational stress, and for the development of stress management interventions with sport performers. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Integrated presentation of ecological risk from multiple stressors.

    Science.gov (United States)

    Goussen, Benoit; Price, Oliver R; Rendal, Cecilie; Ashauer, Roman

    2016-10-26

    Current environmental risk assessments (ERA) do not account explicitly for ecological factors (e.g. species composition, temperature or food availability) and multiple stressors. Assessing mixtures of chemical and ecological stressors is needed as well as accounting for variability in environmental conditions and uncertainty of data and models. Here we propose a novel probabilistic ERA framework to overcome these limitations, which focusses on visualising assessment outcomes by construct-ing and interpreting prevalence plots as a quantitative prediction of risk. Key components include environmental scenarios that integrate exposure and ecology, and ecological modelling of relevant endpoints to assess the effect of a combination of stressors. Our illustrative results demonstrate the importance of regional differences in environmental conditions and the confounding interactions of stressors. Using this framework and prevalence plots provides a risk-based approach that combines risk assessment and risk management in a meaningful way and presents a truly mechanistic alternative to the threshold approach. Even whilst research continues to improve the underlying models and data, regulators and decision makers can already use the framework and prevalence plots. The integration of multiple stressors, environmental conditions and variability makes ERA more relevant and realistic.

  10. Mercury in Nordic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Munthe, John; Waengberg, Ingvar (IVL Swedish Environmental Research Inst., Stockholm (SE)); Rognerud, Sigurd; Fjeld, Eirik (Norwegian Inst. for Water Research (NIVA), Oslo (Norway)); Verta, Matti; Porvari, Petri (Finnish Environment Inst. (SYKE), Helsinki (Finland)); Meili, Markus (Inst. of Applied Environmental Research (ITM), Stockholm (Sweden))

    2007-12-15

    This report provides a first comprehensive compilation and assessment of available data on mercury in air, precipitation, sediments and fish in the Nordic countries. The main conclusion is that mercury levels in Nordic ecosystems continue to be affected by long-range atmospheric transport. The geographical patterns of mercury concentrations in both sediments and fish are also strongly affected by ecosystem characteristics and in some regions possibly by historical pollution. An evaluation of geographical variations in mercury concentrations in precipitation indicates that the influence from anthropogenic sources from Central European areas is still significant. The annual variability of deposition is large and dependant of precipitation amounts. An evaluation of data from stations around the North Sea has indicated a significant decrease in mercury concentrations in precipitation indicating a continuous decrease of emissions in Europe (Waengberg et al., 2007). For mercury in air (TGM), the geographical pattern is less pronounced indicating the influence of mercury emissions and distribution over a larger geographical area (i.e. hemispherical transport). Comparison of recent (surficial) and historical lake sediments show significantly elevated concentrations of mercury most likely caused by anthropogenic atmospheric deposition over the past century. The highest pollution impact was observed in the coastal areas of southern Norway, in south western Finland and in Sweden from the coastal areas in the southwest across the central parts to the north-east. The general increase in recent versus old sediments was 2-5 fold. Data on mercury in Nordic freshwater fish was assembled and evaluated with respect to geographical variations. The fish data were further compared with temporal and spatial trends in mercury deposition and mercury contamination of lake sediments in order to investigate the coupling between atmospheric transport and deposition of mercury and local mercury

  11. Stormwater management and ecosystem services: a review

    Science.gov (United States)

    Prudencio, Liana; Null, Sarah E.

    2018-03-01

    Researchers and water managers have turned to green stormwater infrastructure, such as bioswales, retention basins, wetlands, rain gardens, and urban green spaces to reduce flooding, augment surface water supplies, recharge groundwater, and improve water quality. It is increasingly clear that green stormwater infrastructure not only controls stormwater volume and timing, but also promotes ecosystem services, which are the benefits that ecosystems provide to humans. Yet there has been little synthesis focused on understanding how green stormwater management affects ecosystem services. The objectives of this paper are to review and synthesize published literature on ecosystem services and green stormwater infrastructure and identify gaps in research and understanding, establishing a foundation for research at the intersection of ecosystems services and green stormwater management. We reviewed 170 publications on stormwater management and ecosystem services, and summarized the state-of-the-science categorized by the four types of ecosystem services. Major findings show that: (1) most research was conducted at the parcel-scale and should expand to larger scales to more closely understand green stormwater infrastructure impacts, (2) nearly a third of papers developed frameworks for implementing green stormwater infrastructure and highlighted barriers, (3) papers discussed ecosystem services, but less than 40% quantified ecosystem services, (4) no geographic trends emerged, indicating interest in applying green stormwater infrastructure across different contexts, (5) studies increasingly integrate engineering, physical science, and social science approaches for holistic understanding, and (6) standardizing green stormwater infrastructure terminology would provide a more cohesive field of study than the diverse and often redundant terminology currently in use. We recommend that future research provide metrics and quantify ecosystem services, integrate disciplines to

  12. Cumulative effects of planned industrial development and climate change on marine ecosystems

    Directory of Open Access Journals (Sweden)

    Cathryn Clarke Murray

    2015-07-01

    Full Text Available With increasing human population, large scale climate changes, and the interaction of multiple stressors, understanding cumulative effects on marine ecosystems is increasingly important. Two major drivers of change in coastal and marine ecosystems are industrial developments with acute impacts on local ecosystems, and global climate change stressors with widespread impacts. We conducted a cumulative effects mapping analysis of the marine waters of British Columbia, Canada, under different scenarios: climate change and planned developments. At the coast-wide scale, climate change drove the largest change in cumulative effects with both widespread impacts and high vulnerability scores. Where the impacts of planned developments occur, planned industrial and pipeline activities had high cumulative effects, but the footprint of these effects was comparatively localized. Nearshore habitats were at greatest risk from planned industrial and pipeline activities; in particular, the impacts of planned pipelines on rocky intertidal habitats were predicted to cause the highest change in cumulative effects. This method of incorporating planned industrial development in cumulative effects mapping allows explicit comparison of different scenarios with the potential to be used in environmental impact assessments at various scales. Its use allows resource managers to consider cumulative effect hotspots when making decisions regarding industrial developments and avoid unacceptable cumulative effects. Management needs to consider both global and local stressors in managing marine ecosystems for the protection of biodiversity and the provisioning of ecosystem services.

  13. Measuring Entrepreneurial Ecosystems

    NARCIS (Netherlands)

    Stam, F.C.

    How can entrepreneurial ecosystems and productive entrepreneurship can be traced empirically and how is entrepreneurship related to entrepreneurial ecosystems. The analyses in this chapter show the value of taking a systems view on the context of entrepreneurship. We measure entrepreneurial

  14. Coral reefs - Specialized ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    This paper discusses briefly some aspects that characterize and differentiate coral reef ecosystems from other tropical marine ecosystems. A brief account on the resources that are extractable from coral reefs, their susceptibility to natural...

  15. Ocean warming and acidification: Unifying physiological principles linking organism response to ecosystem change?

    Science.gov (United States)

    Pörtner, H. O.; Bock, C.; Lannig, G.; Lucassen, M.; Mark, F. C.; Stark, A.; Walther, K.; Wittmann, A.

    2011-12-01

    CO2 levels. Furthermore, a decrease in the efficiency of energy production may occur and affect growth and fitness as well as larval development. Different sensitivities of life history stages indicate physiologically sensitive bottlenecks during the life cycle of marine organisms. Available evidence suggests that the concept of oxygen and capacity limited thermal tolerance (OCLTT) provides access to the physiological mechanisms closely defining the sensitivities and responses of species to various stressors. It provides causality and quantifies the levels and changes of performance and resistance, and supports more realistic estimates of species and ecosystem sensitivities to environmental change. The emerging picture of differential sensitivities across animal phyla is in line with existing categorizations of sensitivities from palaeo-observations during the Permian-Triassic mass extinctions (A.H. Knoll et al., Earth and Planetary Science Letters 256, 295-313, 2007).

  16. Investigating fine-scale spatio-temporal predator-prey patterns in dynamic marine ecosystems: a functional data analysis approach

    NARCIS (Netherlands)

    Embling, C.B.; Illian, J.; Armstrong, E.; van der Kooij, J.; Sharples, J.; Camphuysen, K.C.J.; Scott, B.E.

    2012-01-01

    1. Spatial management of marine ecosystems requires detailed knowledge of spatio-temporal mechanisms linking physical and biological processes. Tidal currents, the main driver of ecosystem dynamics in temperate coastal ecosystems, influence predator foraging ecology by affecting prey distribution

  17. Effects of air pollution on ecosystems and biological diversity in the eastern United States.

    Science.gov (United States)

    Lovett, Gary M; Tear, Timothy H; Evers, David C; Findlay, Stuart E G; Cosby, B Jack; Dunscomb, Judy K; Driscoll, Charles T; Weathers, Kathleen C

    2009-04-01

    Conservation organizations have most often focused on land-use change, climate change, and invasive species as prime threats to biodiversity conservation. Although air pollution is an acknowledged widespread problem, it is rarely considered in conservation planning or management. In this synthesis, the state of scientific knowledge on the effects of air pollution on plants and animals in the Northeastern and Mid-Atlantic regions of the United States is summarized. Four air pollutants (sulfur, nitrogen, ozone, and mercury) and eight ecosystem types ranging from estuaries to alpine tundra are considered. Effects of air pollution were identified, with varying levels of certainty, in all the ecosystem types examined. None of these ecosystem types is free of the impacts of air pollution, and most are affected by multiple pollutants. In aquatic ecosystems, effects of acidity, nitrogen, and mercury on organisms and biogeochemical processes are well documented. Air pollution causes or contributes to acidification of lakes, eutrophication of estuaries and coastal waters, and mercury bioaccumulation in aquatic food webs. In terrestrial ecosystems, the effects of air pollution on biogeochemical cycling are also very well documented, but the effects on most organisms and the interaction of air pollution with other stressors are less well understood. Nevertheless, there is strong evidence for effects of nitrogen deposition on plants in grasslands, alpine areas, and bogs, and for nitrogen effects on forest mycorrhizae. Soil acidification is widespread in forest ecosystems across the eastern United States and is likely to affect the composition and function of forests in acid-sensitive areas over the long term. Ozone is known to cause reductions in photosynthesis in many terrestrial plant species. For the most part, the effects of these pollutants are chronic, not acute, at the exposure levels common in the eastern United States. Mortality is often observed only at experimentally

  18. Stressor-induced proteome alterations in zebrafish: A meta-analysis of response patterns

    Energy Technology Data Exchange (ETDEWEB)

    Groh, Ksenia J., E-mail: ksenia.groh@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf (Switzerland); ETH Zürich, Swiss Federal Institute of Technology, Department of Chemistry and Applied Biosciences, 8093 Zürich (Switzerland); Suter, Marc J.-F. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf (Switzerland); ETH Zürich, Swiss Federal Institute of Technology, Department of Environmental Systems Science, 8092 Zürich (Switzerland)

    2015-02-15

    Highlights: • We compared reported proteome changes induced by various stressors in zebrafish. • Several proteins groups frequently responding to diverse stressors were identified. • These included energy metabolism enzymes, heat shock and cytoskeletal proteins. • Insufficient proteome coverage impedes identification of more specific responses. • Further research needs for proteomics in ecotoxicology are discussed. - Abstract: Proteomics approaches are being increasingly applied in ecotoxicology on the premise that the identification of specific protein expression changes in response to a particular chemical would allow elucidation of the underlying molecular pathways leading to an adverse effect. This in turn is expected to promote the development of focused testing strategies for specific groups of toxicants. Although both gel-based and gel-free global characterization techniques provide limited proteome coverage, the conclusions regarding the cellular processes affected are still being drawn based on the few changes detected. To investigate how specific the detected responses are, we analyzed a set of studies that characterized proteome alterations induced by various physiological, chemical and biological stressors in zebrafish, a popular model organism. Our analysis highlights several proteins and protein groups, including heat shock and oxidative stress defense proteins, energy metabolism enzymes and cytoskeletal proteins, to be most frequently identified as responding to diverse stressors. In contrast, other potentially more specifically responding protein groups are detected much less frequently. Thus, zebrafish proteome responses to stress reported by different studies appear to depend mostly on the level of stress rather than on the specific stressor itself. This suggests that the most broadly used current proteomics technologies do not provide sufficient proteome coverage to allow in-depth investigation of specific mechanisms of toxicant action

  19. Stressor-induced proteome alterations in zebrafish: A meta-analysis of response patterns

    International Nuclear Information System (INIS)

    Groh, Ksenia J.; Suter, Marc J.-F.

    2015-01-01

    Highlights: • We compared reported proteome changes induced by various stressors in zebrafish. • Several proteins groups frequently responding to diverse stressors were identified. • These included energy metabolism enzymes, heat shock and cytoskeletal proteins. • Insufficient proteome coverage impedes identification of more specific responses. • Further research needs for proteomics in ecotoxicology are discussed. - Abstract: Proteomics approaches are being increasingly applied in ecotoxicology on the premise that the identification of specific protein expression changes in response to a particular chemical would allow elucidation of the underlying molecular pathways leading to an adverse effect. This in turn is expected to promote the development of focused testing strategies for specific groups of toxicants. Although both gel-based and gel-free global characterization techniques provide limited proteome coverage, the conclusions regarding the cellular processes affected are still being drawn based on the few changes detected. To investigate how specific the detected responses are, we analyzed a set of studies that characterized proteome alterations induced by various physiological, chemical and biological stressors in zebrafish, a popular model organism. Our analysis highlights several proteins and protein groups, including heat shock and oxidative stress defense proteins, energy metabolism enzymes and cytoskeletal proteins, to be most frequently identified as responding to diverse stressors. In contrast, other potentially more specifically responding protein groups are detected much less frequently. Thus, zebrafish proteome responses to stress reported by different studies appear to depend mostly on the level of stress rather than on the specific stressor itself. This suggests that the most broadly used current proteomics technologies do not provide sufficient proteome coverage to allow in-depth investigation of specific mechanisms of toxicant action

  20. Environmental stressors influencing hormones and systems physiology in cattle

    Science.gov (United States)

    2014-01-01

    Environmental stressors undoubtedly influence organismal biology, specifically the endocrine system that, in turn, impact cattle at the systems physiology level. Despite the significant advances in understanding the genetic determinants of the ideal dairy or beef cow, there is a grave lack of understanding of the systems physiology and effects of the environmental stressors that interfere with the endocrine system. This is a major problem because the lack of such knowledge is preventing advances in understanding gene-environment interactions and developing science-based solutions to these challenges. In this review, we synthesize the current knowledge on the nature of the major environmental stressors, such as climate (heat, cold, wind, and humidity), nutrition (feeds, feeding systems, and endocrine disruptors) and management (housing density and conditions, transportation, weaning practices). We summarize the impact of each one of these factors on cattle at the systems level, and provide solutions for the challenges. PMID:24996419

  1. [Appraisal of occupational stressor in petrochemical industry workers].

    Science.gov (United States)

    Tang, Xiao-ping; Tian, Hong-er; Huang, Tong; Li, Zhi-yuan; Hu, Ke-ming; Ge, Xi-yong; Jin, Lei; Gao, Qi; Zhang, Jing-jing; Wang, Yu; Liu, Wen-he

    2009-12-01

    To discuss the origin of occupational stress among petrochemical industry workers and to access the main occupational stressors that impact job satisfaction and mental health of petrochemical industry workers. A survey on occupational stressor was carried out by Occupational Stress Indicator (OSI) in 532 petrochemical industry workers (345 chemical and 187 logistic workers). The environment in workplace of chemical gro