The contribution of leaching to the rapid release of nutrients and carbon in the early decay of wetland vegetation

Our goal was to quantify the coupled process of litter turnover and leaching as a source of nutrients and fixed carbon in oligotrophic, nutrient-limited wetlands. We conducted poisoned and non-poisoned incubations of leaf material from four different perennial wetland plants (Eleocharis spp., Cladium jamaicense, Rhizophora mangle and Spartina alterniflora) collected from different oligotrophic freshwater and estuarine wetland settings. Total phosphorus (TP) release from the P-limited Everglades plant species (Eleocharis spp., C. jamaicense and R. mangle) was much lower than TP release by the salt marsh plant S. alterniflora from N-limited North Inlet (SC). For most species and sampling times, total organic carbon (TOC) and TP leaching losses were much greater in poisoned than non-poisoned treatments, likely as a result of epiphytic microbial activity. Therefore, a substantial portion of the C and P leached from these wetland plant species was bio-available to microbial communities. Even the microbes associated with S. alterniflora from N-limited North Inlet showed indications of P-limitation early in the leaching process, as P was removed from the water column. Leaves of R. mangle released much more TOC per gram of litter than the other species, likely contributing to the greater waterborne [DOC] observed by others in the mangrove ecotone of Everglades National Park. Between the two freshwater Everglades plants, C. jamaicense leached nearly twice as much P than Eleocharis spp. In scaling this to the landscape level, our observed leaching losses combined with higher litter production of C. jamaicense compared to Eleocharis spp. resulted in a substantially greater P leaching from plant litter to the water column and epiphytic microbes. In conclusion, leaching of fresh plant litter can be an important autochthonous source of nutrients in freshwater and estuarine wetland ecosystems.

The Role of the Everglades Mangrove Ecotone Region (EMER) in Regulating Nutrient Cycling and Wetland Productivity in South Florida

The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height <3 m cover 49% of the EMER, particularly in the SE region. These scrub/dwarf mangroves are the result of a combination of low soil phosphorus (P < 59 μg P g dw−1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50 years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50 years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.

Hydrological Conditions Control P Loading and Aquatic Metabolism in an Oligotrophic, Subtropical Estuary

Using high-resolution measures of aquatic ecosystem metabolism and water quality, we investigated the importance of hydrological inputs of phosphorus (P) on ecosystem dynamics in the oligotrophic, P-limited coastal Everglades. Due to low nutrient status and relatively large inputs of terrestrial organic matter, we hypothesized that the ponds in this region would be strongly net heterotrophic and that pond gross primary production (GPP) and respiration (R) would be the greatest during the “dry,” euhaline estuarine season that coincides with increased P availability. Results indicated that metabolism rates were consistently associated with elevated upstream total phosphorus and salinity concentrations. Pulses in aquatic metabolism rates were coupled to the timing of P supply from groundwater upwelling as well as a potential suite of hydrobiogeochemical interactions. We provide evidence that freshwater discharge has observable impacts on aquatic ecosystem function in the oligotrophic estuaries of the Florida Everglades by controlling the availability of P to the ecosystem. Future water management decisions in South Florida must include the impact of changes in water delivery on downstream estuaries.

Personality and job performance: The mediating roles of leader -member exchange quality and action control

The present investigation examined the relationships among personality (as conceptualized by the Big Five Factors), leader-member exchange (LMX) quality, action control, organizational citizenship behaviors (OCB), and overall job performance (OJP). Two mediator variables were proposed and tested in this study: LMX and Action Control. Two-hundred and seven currently employed regular elementary school classroom teachers provided data during the 2000–2001 academic school year. Teachers provided personality, LMX quality (member or subordinate perspective), action control, job tenure, and demographic data. Nine school administrators (i.e., Principals, Assistant Principals) were the source for supervisor ratings of OCB, OJP, and LMX quality (leader or supervisor perspective). In eight of the nine total schools, teachers completed questionnaires during an after-school teacher gathering; in the remaining school location questionnaires were dropped off, distributed to teachers, and re-collected two weeks later. Results indicated a significant relationship between the OCB scale and overall supervisory ratings of OJP. The relationship among the big five factors of personality and OJP did not reach statistical significance, nor did the relationships among personality and OCB. The data indicated that none of the teacher tenure variables (i.e., teacher, school, or time worked with principal tenure) moderated the personality-OCB relationship nor the personality-OJP relationship. Finally, a review of the correlations among the variables of interest precluded conducting a mediation between personality-performance by OCB, mediation of personality-OCB by action control, and mediation of personality-OCB by LMX. In conclusion, the data reveal that personality was not significantly correlated with supervisory ratings of OJP or significantly related to supervisory ratings of overall OCB. Moreover, LMX quality and action control did not mediate the relationships between Personality-OJP nor the Personality-OCB relationship. Significant relationships were found between disengagement and overall LMX quality and between Initiative and overall LMX quality (both LMX-Teacher perspectives) as well as between personality variables and both Disengagement and Initiative action control variables. Despite the limitations inherent in this study, these latter findings suggest “lessons” for teachers and school administrators alike. ^

Interoperable resource brokering with policy-based provisioning and job allocation

The increasing needs for computational power in areas such as weather simulation, genomics or Internet applications have led to sharing of geographically distributed and heterogeneous resources from commercial data centers and scientific institutions. Research in the areas of utility, grid and cloud computing, together with improvements in network and hardware virtualization has resulted in methods to locate and use resources to rapidly provision virtual environments in a flexible manner, while lowering costs for consumers and providers. ^ However, there is still a lack of methodologies to enable efficient and seamless sharing of resources among institutions. In this work, we concentrate in the problem of executing parallel scientific applications across distributed resources belonging to separate organizations. Our approach can be divided in three main points. First, we define and implement an interoperable grid protocol to distribute job workloads among partners with different middleware and execution resources. Second, we research and implement different policies for virtual resource provisioning and job-to-resource allocation, taking advantage of their cooperation to improve execution cost and performance. Third, we explore the consequences of on-demand provisioning and allocation in the problem of site-selection for the execution of parallel workloads, and propose new strategies to reduce job slowdown and overall cost.^

The relationship between job structure, burnout, and coping methods among public school county bus drivers, bus aides, mechanics, and clerical workers

The purpose of this study was to examine the relationship between the structure of jobs and burnout, and to assess to what extent, if any this relationship was moderated by individual coping methods. This study was supported by the Karasek's (1998) Job Demand-Control-Support theory of work stress as well as Maslach and Leiter's (1993) theory of burnout. Coping was examined as a moderator based on the conceptualization of Lazarus and Folkman (1984). ^ Two overall overarching questions framed this study: (a) what is the relationship between job structure, as operationalized by job title, and burnout across different occupations in support services in a large municipal school district? and (b) To what extent do individual differences in coping methods moderate this relationship? ^ This study was a cross-sectional study of county public school bus drivers, bus aides, mechanics, and clerical workers (N = 253) at three bus depot locations within the same district using validated survey instruments for data collection. Hypotheses were tested using simultaneous regression analyses. ^ Findings indicated that there were statistically significant and relevant relationships among the variables of interest; job demands, job control, burnout, and ways of coping. There was a relationship between job title and physical job demands. There was no evidence to support a relationship between job title and psychological demands. Furthermore, there was a relationship between physical demands, emotional exhaustion and personal accomplishment; key indicators of burnout. ^ Results showed significant correlations between individual ways of coping as a moderator between job structure, operationalized by job title, and individual employee burnout adding empirical evidence to the occupational stress literature. Based on the findings, there are implications for theory, research, and practice. For theory and research, the findings suggest the importance of incorporating transactional models in the study of occupational stress. In the area of practice, the findings highlight the importance of enriching jobs, increasing job control, and providing individual-level training related to stress reduction.^

Benthic Exchange of C, N, and P Along the Estuarine Ecotone of Lower Taylor Slough, Florida (USA): Effect of Seasonal Flows and Phosphorus Availability

The southern Everglades and Florida Bay have experienced a nearly 50 % reduction in freshwater flow resulting in increased salinity and landward expansion of mangrove forest. Given the marine end-member is a natural source of P to this region, it is necessary to understand the interactions between inflows and P availability in controlling the exchange of materials across the mangrove ecotone. From 2007 to 2008, we used sediment core incubations to quantify fluxes of dissolved inorganic N and P and dissolved organic carbon (DOC) in three ecotone areas (dwarf mangrove, pond, and bay). Experiments were repeated seasonally over 2 years involving P-enriched surface water as a factor. We saw consistent uptake of soluble reactive P (SRP), DOC, and nitrate + nitrite (N+N) by the soils/sediments and release of ammonium (NH4 +) from soils/sediments to the water column across all sites and seasons. P enrichment had no discernible effect on DIN or DOC flux, suggesting that rapid P uptake may have been more geochemically mediated. However, uptake of added P occurred across all sites and seasons, reflecting high uptake capacity in this carbonate system and the potential of the mangrove ecotone to sequester P as it becomes more available.

Integrated Carbon Budget Models for the Everglades Terrestrial-Coastal-Oceanic Gradient: Current Status and Needs for Inter-Site Comparisons

Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets for riverine mangrove, freshwater marsh, and seagrass meadows, providing insights into the magnitude of C accumulation and lateral aquatic C transport. Rates of net C production in the riverine mangrove forest exceeded those reported for many tropical systems, including terrestrial forests, but there are considerable uncertainties around those estimates due to the high potential for gain and loss of C through aquatic fluxes. C production was approximately balanced between gain and loss in Everglades marshes; however, the contribution of periphyton increases uncertainty in these estimates. Moreover, while the approaches used for these initial estimates were informative, a resolved approach for addressing areas of uncertainty is critically needed for coastal wetland ecosystems. Once resolved, these C balance estimates, in conjunction with an understanding of drivers and key ecosystem feedbacks, can inform cross-system studies of ecosystem response to long-term changes in climate, hydrologic management, and other land use along coastlines.

Red mangrove juvenile mangroves and mangrove peat soils at the wetland mesocosm facility. Plants were exposed to phosphorus addition and defolitation, mimicing effects of marine storms on coastal mangrove ecosystems.

http://digitalcommons.fiu.edu/fce_lter_photos/1334/thumbnail.jpg

The Validity of Broad and Narrow Personality Traits For Predicting Job Performance: The Differential Effects of Time

Research into the dynamicity of job performance criteria has found evidence suggesting the presence of rank-order changes to job performance scores across time as well as intraindividual trajectories in job performance scores across time. These findings have influenced a large body of research into (a) the dynamicity of validities of individual differences predictors of job performance and (b) the relationship between individual differences predictors of job performance and intraindividual trajectories of job performance. In the present dissertation, I addressed these issues within the context of the Five Factor Model of personality. The Five Factor Model is arranged hierarchically, with five broad higher-order factors subsuming a number of more narrowly tailored personality facets. Research has debated the relative merits of broad versus narrow traits for predicting job performance, but the entire body of research has addressed the issue from a static perspective -- by examining the relative magnitude of validities of global factors versus their facets. While research along these lines has been enlightening, theoretical perspectives suggest that the validities of global factors versus their facets may differ in their stability across time. Thus, research is needed to not only compare the relative magnitude of validities of global factors versus their facets at a single point in time, but also to compare the relative stability of validities of global factors versus their facets across time. Also necessary to advance cumulative knowledge concerning intraindividual performance trajectories is research into broad vs. narrow traits for predicting such trajectories. In the present dissertation, I addressed these issues using a four-year longitudinal design. The results indicated that the validities of global conscientiousness were stable across time, while the validities of conscientiousness facets were more likely to fluctuate. However, the validities of emotional stability and extraversion facets were no more likely to fluctuate across time than those of the factors. Finally, while some personality factors and facets predicted performance intercepts (i.e., performance at the first measurement occasion), my results failed to indicate a significant effect of any personality variable on performance growth. Implications for research and practice are discussed.

THE DARK PERSONALITY AND JOB SUCCESS IN THE UNITED STATES ARMY: USE OF INTERPERSONAL MANIPULATION IN THE WORKPLACE

This dissertation relates job desires and outcomes to the Dark Personality (Psychopathy, Machiavellianism, Narcissism, Low Agreeableness, Low Honesty-Humility) in the United States Army. It purports that individuals high on the Dark Personality desire more power, money, and status, and that they obtain jobs that afford them these luxuries by using manipulation at work. Two pilot studies used samples of United States Army members to create and test index variables: Dark Personality, Total Manipulation in the workplace, Desire for Job Success, and Total Job Success in the Army. Individual personality traits, manipulation tactics, and job desires were examined in secondary analyses. Using a sample of 468 United States Army Members, central analyses indicated that Army members high on the Dark Personality desired Job Success. Likewise, army members higher on the Dark Personality used more Manipulation tactics at work, including the egregious tactics. Yet, using more Manipulation tactics at work predicted lower levels of Job Success in the Army. Most manipulation tactics had a negative impact on Job Success, with the exception of soft tactics like Reason and Responsibility Invocation. Together, these results indicate that selective use of soft manipulation predicted Job Success, but use of more manipulation tactics predicted less Job Success in the Army. Curvilinear results indicated that being either very low or very high on the Dark Personality predicted more Job Success in the Army, whereas having intermediate levels of the Dark Personality predicted less Job Success. Finally, possessing the Dark Personality and using more Manipulation tactics at work, together, predicted less Job Success in the Army. Collectively, the results indicate that army members with intermediate levels of the Dark Personality want more powerful and high paying jobs, yet their strategy of manipulating their coworkers to move up the job ladder does not result in higher ranking, higher paying Army positions. However, Army members highest on the Dark Personality achieved job success, defying the maladaptive influence that antisocial personality traits and manipulative behaviour had on job success for most Army members. Therefore, this dissertation indicates that successful corporate scoundrels exist in the Army, but there are few of them.

The elderly care and domestic services sector during the recent economic crisis. The case of Italy, Spain and France.

Over the past ten years in Italy, Spain and France, the demographic pressure and the increasing women’s participation in labour market have fuelled the expansion of the private provision of domestic and care services. In order to ensure the difficult balance between affordability, quality and job creation, each countries’ response has been different. France has developed policies to sustain the demand side introducing instruments such as vouchers and fiscal schemes, since the mid of the 2000s. Massive public funding has contributed to foster a regular market of domestic and care services and France is often presented as a “best practices” of those policies aimed at encouraging a regular private sector. Conversely in Italy and Spain, the development of a private domestic and care market has been mostly uncontrolled and without a coherent institutional design: the osmosis between a large informal market and the regular private care sector has been ensured on the supply side by migrant workers’ regularizations or the introduction of new employment regulations . The analysis presented in this paper aims to describe the response of these different policies to the challenges imposed by the current economic crisis. In dealing with the retrenchment of public expenditure and the reduced households’ purchasing power, Italy, Spain and France are experiencing greater difficulties in ensuring a regular private sector of domestic and care services. In light of that, the paper analyses the recent economic conjuncture presenting some assumptions about the future risk of deeper inequalities rising along with the increase of the process of marketization of domestic and care services in all the countries under analysis.    

Generations and intention to leave current job : Belgian nurses in the workplace

This master thesis aims to identify work-related factors making Belgian nurses consider leaving their job voluntary and to compare the work-related factors across different generations. The purpose of this master thesis has a descriptive nature of research. The research approach chosen is a deductive approach and the research design chosen is a quantitative research design. Cluster sampling in combination with simple random sampling was used as sampling technique. 128 nurses were surveyed from April to May 2016. Nurses who reported to leave the organization due to retirement reasons, temporary employment contract or maternity leave were excluded from the study as this study investigates the voluntary turnover intention. A total of 68 nurses were included in the study which indicates an overall response rate of 53 %. Numerous of the findings in this master thesis are consistent with previous studies on turnover intention of different generations in other western-countries than Belgium. The work-related factor workload was most often reported by Belgian nurses with no intention to leave their job. Belgian nurses with an intention to leave their job indicated most often the work-related factor (non-)financial benefits. The generation-specific findings indicated both similarities and differences between the work-related factors selected. It was observed that Baby Boomers with an intention to leave their job selected most often variables related to the work-related factors (non-)financial benefits, supportive organization and workload. The variable lack of recognition appeared among Baby Boomers with an intention and no intention to leave their job. Surprisingly was the often selected variables lack of direct and/clear feedback on performances and unsupportive supervisor among Baby Boomers with professional turnover intention. Further, it was observed that Generation Xers with an intention to leave their job selected most often variables related to the work-related factors supportive organization, communication, (non-)financial benefits, work content and workload. The variables inadequate opportunity for advancement/professional growth and imbalance work-life appeared among Generation Xers with an intention and no intention to leave their job. Generation Yers with an intention to leave their job selected most frequently variables related to the work-related factors (non-)financial benefits, workload and commitment. The variables inadequate salary and opportunities elsewhere appeared among nurses with an intention and no intention to leave their job. Surprisingly was the often selected variable inadequate salary among Generation Yers with professional turnover intention.

Information and communication technology demands at work : the association with job strain, effort-reward imbalance and self-rated health in different socio-economic strata

PURPOSE: The use of information and communication technology (ICT) is common in modern working life. ICT demands may give rise to experience of work-related stress. Knowledge about ICT demands in relation to other types of work-related stress and to self-rated health is limited. Consequently, the aim of this study was to examine the association between ICT demands and two types of work-related stress [job strain and effort-reward imbalance (ERI)] and to evaluate the association between these work-related stress measures and self-rated health, in general and in different SES strata. METHODS: This study is based on cross-sectional data from the Swedish Longitudinal Occupational Survey of Health collected in 2014, from 14,873 gainfully employed people. ICT demands, job strain, ERI and self-rated health were analysed as the main measures. Sex, age, SES, lifestyle factors and BMI were used as covariates. RESULTS: ICT demands correlated significantly with the dimensions of the job strain and ERI models, especially with the demands (r = 0.42; p < 0.01) and effort (r = 0.51; p < 0.01) dimensions. ICT demands were associated with suboptimal self-rated health, also after adjustment for age, sex, SES, lifestyle and BMI (OR 1.49 [95 % CI 1.36-1.63]), but job strain (OR 1.93 [95 % CI 1.74-2.14) and ERI (OR 2.15 [95 % CI 1.95-2.35]) showed somewhat stronger associations with suboptimal self-rated health. CONCLUSION: ICT demands are common among people with intermediate and high SES and associated with job strain, ERI and suboptimal self-rated health. ICT demands should thus be acknowledged as a potential stressor of work-related stress in modern working life.

The role of networking and social media tools during job search: an information behaviour perspective.

The paper presents a critical analysis of the extant literature pertaining to the networking behaviours of young jobseekers in both offline and online environments. A framework derived from information behaviour theory is proposed as a basis for conducting further research in this area. Method. Relevant material for the review was sourced from key research domains such as library and information science, job search research, and organisational research. Analysis. Three key research themes emerged from the analysis of the literature: (1) social networks, and the use of informal channels of information during job search, (2) the role of networking behaviours in job search, and (3) the adoption of social media tools. Tom Wilson’s general model of information behaviour was also identified as a suitable framework to conduct further research. Results. Social networks have a crucial informational utility during the job search process. However, the processes whereby young jobseekers engage in networking behaviours, both offline and online, remain largely unexplored. Conclusion. Identification and analysis of the key research themes reveal opportunities to acquire further knowledge regarding the networking behaviours of young jobseekers. Wilson’s model can be used as a framework to provide a holistic understanding of the networking process, from an information behaviour perspective.