scholarly journals Nutrient excretion by fish supports a variable but significant proportion of lake primary productivity over 15 years

Ecology ◽  
2021 ◽  
Author(s):  
Carrie Ann Sharitt ◽  
María J. González ◽  
Tanner J. Williamson ◽  
Michael J. Vanni
2018 ◽  
Vol 84 (7) ◽  
Author(s):  
Hee-Sung Bae ◽  
Elise Morrison ◽  
Jeffrey P. Chanton ◽  
Andrew Ogram

ABSTRACTThe objective of this study was to investigate the interaction of the nitrogen (N) cycle with methane production in the Florida Everglades, a large freshwater wetland. This study provides an initial analysis of the distribution and expression of N-cycling genes in Water Conservation Area 2A (WCA-2A), a section of the marsh that underwent phosphorus (P) loading for many years due to runoff from upstream agricultural activities. The elevated P resulted in increased primary productivity and an N limitation in P-enriched areas. Results from quantitative real-time PCR (qPCR) analyses indicated that the N cycle in WCA-2A was dominated bynifHandnirK/S, with an increasing trend in copy numbers in P-impacted sites. ManynifHsequences (6 to 44% of the total) andnifHtranscript sequences (2 to 49%) clustered with the methanogenicEuryarchaeota, in stark contrast to the proportion of core gene sequences representingArchaea(≤0.27% of SSU rRNA genes) for the WCA-2A microbiota. Notably, archaealnifHgene transcripts were detected at all sites and comprised a significant proportion of totalnifHtranscripts obtained from the unimpacted site, indicating that methanogens are actively fixing N2. Laboratory incubations with soils taken from WCA-2A producednifHtranscripts with the production of methane from H2plus CO2and acetate as electron donors and carbon sources. Methanogenic N2fixation is likely to be an important, although largely unrecognized, route through which fixed nitrogen enters the anoxic soils of the Everglades and may have significant relevance regarding methane production in wetlands.IMPORTANCEWetlands are the most important natural sources of the greenhouse gas methane, and much of that methane emanates from (sub)tropical peatlands. Primary productivity in these peatlands is frequently limited by the availability of nitrogen or phosphorus; however, the response to nutrient limitations of microbial communities that control biogeochemical cycling critical to ecosystem function may be complex and may be associated with a range of processes, including methane production. We show that many, if not most, of the methanogens in the peatlands of the Florida Everglades possess thenifHgene and actively express it for N2fixation coupled with methanogenesis. These findings indicate that archaeal N2fixation would play crucial role in methane emissions and overall N cycle in subtropical wetlands suffering N limitation.


Crisis ◽  
2015 ◽  
Vol 36 (3) ◽  
pp. 211-219 ◽  
Author(s):  
Vinod Singaravelu ◽  
Anne Stewart ◽  
Joanna Adams ◽  
Sue Simkin ◽  
Keith Hawton

Abstract. Background: The Internet is used by young people at risk of self-harm to communicate, find information, and obtain support. Aims: We aimed to identify and analyze websites potentially accessed by these young people. Method: Six search terms, relating to self-harm/suicide and depression, were input into four search engines. Websites were analyzed for access, content/purpose, and tone. Results: In all, 314 websites were included in the analysis. Most could be accessed without restriction. Sites accessed by self-harm/suicide search terms were mostly positive or preventive in tone, whereas sites accessed by the term ways to kill yourself tended to have a negative tone. Information about self-harm methods was common with specific advice on how to self-harm in 15.8% of sites, encouragement of self-harm in 7.0%, and evocative images of self-harm/suicide in 20.7%. Advice on how to get help was given in 56.1% of sites. Conclusion: Websites relating to suicide or self-harm are easily accessed. Many sites are potentially helpful. However, a significant proportion of sites are potentially harmful through normalizing or encouraging self-harm. Enquiry regarding Internet use should be routinely included while assessing young people at risk.


Crisis ◽  
2020 ◽  
pp. 1-8
Author(s):  
Christian Ulrich Eriksen ◽  
Flemming Konradsen ◽  
Thilde Vildekilde

Abstract. Background: Information on methods of suicide is available online, and access to information on methods of suicide appears to contribute to a small but significant proportion of suicides. There is limited documentation of how methods of suicide are being profiled, as well as what content exists in other languages than English. Aim: We aimed to analyze and compare how methods of suicide are profiled on Danish and English-language websites. Method: We applied a categorization and content analysis of websites describing methods of suicide. Sites were retrieved by applying widely used Danish and English-language search terms. Results: A total of 136 English-language websites and 106 Danish-language websites were included for analysis. Websites were more often categorized as prevention or support sites, academic or policy sites, and against suicide sites than dedicated suicide sites (i.e., pro-suicide sites), or information sites. However, information on methods of suicide was available, and 20.1% and 8.9% of the English and Danish-language sites, respectively, suggested that a particular method of suicide was quick, easy, painless, or certain to result in death. Limitations: Only one author coded and analyzed all websites. A further operationalization of the content analysis checklist is warranted to increase reliability. Conclusion: The websites primarily had a prevention or anti-suicide focus, but information on methods of suicide was available, requiring an increased focus on how to diminish the negative effects of harmful online content.


2019 ◽  
Vol 40 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Anja Wertag ◽  
Denis Bratko

Abstract. Prosocial behavior is intended to benefit others rather than oneself and is positively linked to personality traits such as Agreeableness and Honesty-Humility, and usually negatively to the Dark Triad traits (i.e., Machiavellianism, narcissism, and psychopathy). However, a significant proportion of the research in this area is conducted solely on self-report measures of prosocial behavior. Therefore, the aim of this study was to investigate the relationship between prosociality and the basic (i.e., HEXACO) and dark personality traits, comparing their contribution in predicting both self-reported prosociality and prosocial behavior. Results of the hierarchical regression analyses showed that the Dark Triad traits explain prosociality and prosocial behavior above and beyond the HEXACO traits, emphasizing the importance of the Dark Triad in the personality space.


Author(s):  
Roberto González-De Zayas ◽  
Liosban Lantigua Ponce de León ◽  
Liezel Guerra Rodríguez ◽  
Felipe Matos Pupo ◽  
Leslie Hernández-Fernández

The Cenote Jennifer is an important and unique aquatic sinkhole in Cayo Coco (Jardines del Rey Tourist Destination) that has brackish to saline water. Two samplings were made in 1998 and 2009, and 4 metabolism community experiments in 2009. Some limnological parameters were measured in both samplings (temperature, salinity, pH, dissolved oxygen major ions, hydrogen sulfide, nutrients and others). Community metabolism was measured through incubated oxygen concentration in clear and dark oxygen bottles. Results showed that the sinkhole limnology depends on rainfall and light incidence year, with some stratification episodes, due to halocline or oxycline presence, rather than thermocline. The sinkhole water was oligotrophic (total nitrogen of 41.5 ± 22.2 μmol l−1 and total phosphorus of 0.3 ± 0.2 μmol l−1) and with low productivity (gross primary productivity of 63.0 mg C m−2 d−1). Anoxia and hypoxia were present at the bottom with higher levels of hydrogen sulfide, lower pH and restricted influence of the adjacent sea (2 km away). To protect the Cenote Jennifer, tourist exploitation should be avoided and more resources to ecological and morphological studies should be allocated, and eventually use this aquatic system only for specialized diving. For conservation purposes, illegal garbage disposal in the surrounding forest should end.


2018 ◽  
pp. 131-141 ◽  
Author(s):  
A. N. Savrukov ◽  
N. T. Savrukov ◽  
E. A. Kozlovskaya

The article analyzes the current state and level of development of publicprivate partnership (PPP) projects in the subjects of the Russian Federation. The authors conclude that a significant proportion of projects is implemented on a concession basis at the municipal level in the communal sphere. A detailed analysis of the project data showed that the structure of the projects is deformed in favor of the central regions of the Russian Federation, and a significant share in the total amount of financing falls on the transport sector. At the stage of assessing the level of development by the subjects of the Russian Federation, criteria were proposed, and index and integral indicators were used, which ensured comparability of the estimates obtained. At the end of the analysis, the regions were ranked and clustered according to the level of PPP development, which allowed to reveal the number and structure of leaders and outsiders.


2017 ◽  
Vol 71 (3) ◽  
pp. 187-201 ◽  
Author(s):  
W Yang ◽  
T Lu ◽  
S Liu ◽  
J Jian ◽  
F Shi ◽  
...  

2019 ◽  
Vol 98 (1) ◽  
pp. 22-44 ◽  
Author(s):  
Rachael E. Comunale

This article examines the development of political opposition in Scotland from 1695 to 1701 in the context of the Company of Scotland Trading to Africa and the Indies. It is argued that the potency of the political movement inspired by Darien derived from the view that King William was directly implicated in the failure of the colony. Three episodes in the Company's history—the loss of subscriptions in Hamburg, the appearance of memorials in the new world prohibiting English aid to the colony and the imprisonment of Darien sailors by the Spanish authorities—are examined in detail. The ramification of these controversies was increasingly seen as the result not of English interference, but rather the crown's refusal to act on behalf of the Company. Because a significant proportion of the population was invested in the Company, and because the press helped to keep Darien in the forefront of public consciousness, these issues transformed Darien into a major political grievance that united disparate political factions in support of a single cause. Although the alliance inspired by Darien was temporary, it, nonetheless, played a crucial role in disrupting the political status quo.


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