Autumn lipid reserves, overwinter lipid depletion, and high winter mortality of rainbow trout in experimental lakes.

2021 ◽  
Author(s):  
Peter A Biro ◽  
John R. Post ◽  
Christa Beckmann
Keyword(s):  
Rainbow Trout ◽  
Current Knowledge ◽  
Field Studies ◽  
Winter Mortality ◽  
Laboratory Studies ◽  
High Food ◽  
Overwinter Survival ◽  
Winter Conditions ◽  
Modelling Studies ◽  
Overwinter Mortality

Accumulation of lipid reserves is considered important for the overwinter survival of many animals. Much of our current knowledge comes from either laboratory studies, or field studies that are not well controlled, but rarely is overwinter survival directly estimated to evaluate selective mortality. Here, we studied plasticity of lipid storage, overwinter lipid depletion, and subsequent survival rainbow trout stocked into experimental lakes that differed in productivity but experienced the same local winter conditions. Productive lakes produced trout with higher lipid content and steeper allometric slopes in contrast to trout in low food lakes; all substantially lower than those determined in the lab. trout from low productivity lakes emerged from winter in poor condition, close to the expected critical minimum needed for survival, in comparison to survivors from higher productivity lakes. As expected, overwinter mortality was lipid-dependent, with fish in low food lakes nearing 90% mortality and about 60% in high food lakes. Importantly, these estimates are higher than from laboratory (ca. 70%) and modelling studies (0 to 14%) for this species

scholarly journals Rabies in Our Neighbourhood: Preparedness for an Emerging Infectious Disease

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 375
Author(s):  
Michael P. Ward ◽  
Victoria J. Brookes
Keyword(s):  
Infectious Disease ◽  
Southeast Asia ◽  
Field Studies ◽  
Emerging Infectious Disease ◽  
Disease Response ◽  
Canine Rabies ◽  
Research Activities ◽  
Potential Reservoir ◽  
Modelling Studies ◽  
Sociological Studies

Emerging infectious disease (EID) events have the potential to cause devastating impacts on human, animal and environmental health. A range of tools exist which can be applied to address EID event detection, preparedness and response. Here we use a case study of rabies in Southeast Asia and Oceania to illustrate, via nearly a decade of research activities, how such tools can be systematically integrated into a framework for EID preparedness. During the past three decades, canine rabies has spread to previously free areas of Southeast Asia, threatening the rabies-free status of countries such as Timor Leste, Papua New Guinea and Australia. The program of research to address rabies preparedness in the Oceanic region has included scanning and surveillance to define the emerging nature of canine rabies within the Southeast Asia region; field studies to collect information on potential reservoir species, their distribution and behaviour; participatory and sociological studies to identify priorities for disease response; and targeted risk assessment and disease modelling studies. Lessons learnt include the need to develop methods to collect data in remote regions, and the need to continuously evaluate and update requirements for preparedness in response to evolving drivers of emerging infectious disease.

Foliar Penetration and Phytotoxicity of Paraquat as Influenced by Peanut Cultivar1

1991 ◽  
Vol 18 (2) ◽  
pp. 67-71 ◽  
Author(s):  
G. Wehtje ◽  
J. W. Wilcut ◽  
J. A. McGuire ◽  
T. V. Hicks
Keyword(s):  
Arachis Hypogaea ◽  
Untreated Control ◽  
Field Studies ◽  
Yield Potential ◽  
Laboratory Studies ◽  
Foliar Absorption ◽  
Arachis Hypogaea L ◽  
Herbicide Treatments ◽  
Peanut Cultivars

Abstract Field studies were conducted over a three year period to examine the sensitivity of four peanut (Arachis hypogaea L.) cultivars (Florunner, Sunrunner, Southern runner, and NC 7) to foliar applications of paraquat (1, 1′-dimethyl-4, 4′-bipyridinium ion). Treatments included an untreated control and four herbicide treatments: paraquat applied alone at 0.14 and 0.28 kg/ha, or tank mixed with alachlor [2-chloro-N-(2, 6-diethylphenyl)-N-(methoxymethyl)acetamide] at 4.40 kg/ha. Weeds were hand-removed so that only herbicidal treatments were variables. Paraquat phytotoxicity did not differ between cultivars. No cultivar evaluated was abnormally sensitive nor tolerant to any paraquat-containing treatment. Laboratory studies utilizing radio labelled paraquat revealed that foliar absorption and translocation of paraquat did not vary between peanut cultivars. Yield differences were attributed to differences in yield potential between cultivars.

scholarly journals STUDI LALAT PENGOROK DAUN LIRIOMYZA SPP. PADA PERTANAMAN BAWANG DAUN, DAN PARASITOID OPIUS CHROMATOMYIAE BELOKOBYLSKIJ & WHARTON (HYMENOPTERA: BRACONIDAE)

2009 ◽  
Vol 9 (1) ◽  
pp. 22-31
Author(s):  
Rusli Rustam ◽  
Aunu Rauf ◽  
Nina Maryana ◽  
Pudjianto Pudjianto ◽  
Dadang Dadang
Keyword(s):  
Age Distribution ◽  
Host Density ◽  
Field Studies ◽  
Reproductive Value ◽  
Laboratory Studies ◽  
Demographic Parameter ◽  
Liriomyza Huidobrensis ◽  
Stable Age Distribution ◽  
Net Reproduction ◽  
Density Results

Studies on Leafminer Liriomyza spp. in Green Onion Fields, and Parasitoid Opius chromatomyiae Belokobylskij & Wharton (Hymenoptera: Braconidae).  Field studies were conducted to determine population abundance of leafminers and their parasitoids in green onion fields in Puncak, West Java. In addition to that, laboratory studies were carried out to determine demographic parameter of Opius chromatomyiae as well as response of parasitoid to increasing host density. Results revealed that green onions were infested by two species of leafminers, Liriomyza huidobrensis and Liriomyza chinensis.  Leafminer flies emerged from Erwor leaves (54.5) were significantly higher than those of RP leaves (18.65) (P = 0.0005). However, number of  leafminer flies caught on sticky traps was not statistically different (P = 0.297).  Two species of parasitoid, Hemiptarsenus varicornis and O. chromatomyiae, were associated with leafminers in green onion fields. Higher number of parasitoids emerged from Erwor leaves (13.68) as compared to RP (6.90) (P =0.0007 ). However, level of parasitization were 24.36% on Erwor and 28.45% on RP, and was not significantly different (P = 0.387). Laboratory studies indicated that net reproduction (Ro) of O. chromatomyiae was 28.55, generation time (T) 15.96 days, intrinsic growth rate 0.21, and total of reproductive value 223.64.  The stable age distribution of parasitoid were 37.93% eggs, 24.92% larvae, 20.36% pupae and 16.78% adults.  The parasitoid showed functional response type II to increasing host density, with a = 0.08 and Th = 2.58.

scholarly journals Passive Acoustic Monitoring of Chaco Chachalaca (Ortalis canicollis) Over a Year: Vocal Activity Pattern and Monitoring Recommendations

2021 ◽  
Vol 14 ◽  
pp. 194008292110582
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann
Keyword(s):  
Activity Pattern ◽  
Current Knowledge ◽  
Field Studies ◽  
Acoustic Monitoring ◽  
Diel Activity ◽  
Passive Acoustic Monitoring ◽  
Vocal Activity ◽  
Passive Acoustic ◽  
Recognition Software ◽  
Brazilian Pantanal

Chaco Chachalaca ( Ortalis canicollis) is a declining Neotropical bird, for which our current knowledge about its natural history is very limited. Here, we evaluated for first time the utility of passive acoustic monitoring, coupled with automated signal recognition software, to monitor the Chaco Chachalaca, described the vocal behavior of the species across the diel and seasonal cycle patterns, and proposed an acoustic monitoring protocol to minimize error in the estimation of the vocal activity rate. We recorded over a complete annual cycle at three sites in the Brazilian Pantanal. The species was detected on 99% of the monitoring days, proving that this technique is a reliable method for detecting the presence of the species. Chaco Chachalaca was vocally active throughout the day and night, but its diel activity pattern peaked between 0500 and 0900. The breeding season of Chaco Chachalaca in the Brazilian Pantanal, based on seasonal changes in vocal activity, seems to occur during the last months of the dry season, with a peak in vocal activity between August and October. Our results could guide future surveys aiming to detect the presence of the species, both using traditional or acoustic surveys, or to evaluate changes in population abundance using passive acoustic monitoring, for which recorders should be left in the field for a minimum period of nine days to obtain a low-error estimate of the vocal activity of the species. Our results suggest that passive acoustic monitoring might be useful, as a complementary tool to field studies, for monitoring other cracids, a family with several threatened species that are reluctant to human presence.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

scholarly journals Sympatric Atlantic puffins and razorbills show contrasting responses to adverse marine conditions during winter foraging within the North Sea

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Katie St. John Glew ◽  
Sarah Wanless ◽  
Michael P. Harris ◽  
Francis Daunt ◽  
Kjell Einar Erikstad ◽  
...  
Keyword(s):  
North Sea ◽  
Environmental Conditions ◽  
Trophic Position ◽  
Survival Rates ◽  
Sympatric Species ◽  
Ecological Niches ◽  
Overwinter Survival ◽  
The North ◽  
Winter Conditions ◽  
The North Sea

Abstract Background Natural environments are dynamic systems with conditions varying across years. Higher trophic level consumers may respond to changes in the distribution and quality of available prey by moving to locate new resources or by switching diets. In order to persist, sympatric species with similar ecological niches may show contrasting foraging responses to changes in environmental conditions. However, in marine environments this assertion remains largely untested for highly mobile predators outside the breeding season because of the challenges of quantifying foraging location and trophic position under contrasting conditions. Method Differences in overwinter survival rates of two populations of North Sea seabirds (Atlantic puffins (Fratercula arctica) and razorbills (Alca torda)) indicated that environmental conditions differed between 2007/08 (low survival and thus poor conditions) and 2014/15 (higher survival, favourable conditions). We used a combination of bird-borne data loggers and stable isotope analyses to test 1) whether these sympatric species showed consistent responses with respect to foraging location and trophic position to these contrasting winter conditions during periods when body and cheek feathers were being grown (moult) and 2) whether any observed changes in moult locations and diet could be related to the abundance and distribution of potential prey species of differing energetic quality. Results Puffins and razorbills showed divergent foraging responses to contrasting winter conditions. Puffins foraging in the North Sea used broadly similar foraging locations during moult in both winters. However, puffin diet significantly differed, with a lower average trophic position in the winter characterised by lower survival rates. By contrast, razorbills’ trophic position increased in the poor survival winter and the population foraged in more distant southerly waters of the North Sea. Conclusions Populations of North Sea puffins and razorbills showed contrasting foraging responses when environmental conditions, as indicated by overwinter survival differed. Conservation of mobile predators, many of which are in sharp decline, may benefit from dynamic spatial based management approaches focusing on behavioural changes in response to changing environmental conditions, particularly during life history stages associated with increased mortality.

Use of Seedling Growth Parameters to Classify Soybean (Glycine max) Cultivar Sensitivity to Sulfentrazone

1999 ◽  
Vol 13 (3) ◽  
pp. 530-535 ◽  
Author(s):  
Zhaohu Li ◽  
Robert H. Walker ◽  
Glenn Wehtje ◽  
H. Gary Hancock
Keyword(s):  
Glycine Max ◽  
Seedling Growth ◽  
Root Length ◽  
Reduction Method ◽  
Growth Parameters ◽  
Field Evaluation ◽  
Relative Sensitivity ◽  
Field Studies ◽  
Laboratory Studies ◽  
Length Reduction

Hypocotyl and root length reduction of soybean (Glycine max) seedlings when seeds were exposed to sulfentrazone during germination were used as indices to classify cultivar response to soil-applied sulfentrazone. Seeds of ‘Stonewall’ (sulfentrazone tolerant) and ‘Asgrow 6785’ (sulfentrazone sensitive) were imbibed and allowed to germinate in 0, 1, 5, 10, and 50 ppm aqueous sulfentrazone solutions for 4 d. Hypocotyl and root lengths were reduced in both cultivars, but the reductions were greater for Asgrow 6785 than for Stonewall. Subsequently, the relative sensitivity of 28 cultivars to sulfentrazone was independently determined by two variations of the hypocotyl reduction method (both conducted in the laboratory) and by traditional full-season field evaluation. Results from laboratory and field studies were in agreement for cultivars distinctly sensitive or tolerant to sulfentrazone. However, cultivars with intermediate tolerance in laboratory studies produced variable responses in the field.

The Effects of Capillaria-Hepatica (Nematoda) on Natality and Survival to Weaning in Balb/C Mice

1986 ◽  
Vol 34 (5) ◽  
pp. 677 ◽  
Author(s):  
GR Singleton ◽  
DM Spratt
Keyword(s):  
Simulation Models ◽  
Field Studies ◽  
Mouse Strains ◽  
Breeding Period ◽  
Slight Variation ◽  
Standard Laboratory ◽  
Laboratory Studies ◽  
Significant Delay ◽  
Capillaria Hepatica ◽  
Computer Simulation Models

Pathogenicity of the nematode Capillaria hepatica was assessed in female BALB/c mice in terms of the parasite's effect on natality and on survival of young to weaning. C. hepatica infection in female BALB/c mice maintained under standard laboratory conditions resulted in: a significant delay in production of second litters; a significant reduction in the number of live young born and in the number of live young weaned per female over a 90-day breeding period; a significant reduction in the number of live young weaned per litter; but no marked difference in the number of live young born per litter. Demographic studies and computer simulation models infer that 'mouse plagues' can be suppressed if productivity is maintained below an attainable threshhold. The magnitude of the reduction in 'productivity' caused by C. hepatica, and the slight variation in susceptibility of mouse strains to such infection, support the proposal that strategic use of C. hepatica may prevent formation of 'mouse plagues'. This postulate stems from carefully controlled laboratory studies but now requires confirmation from field studies.

scholarly journals Heterogeneous reactions of mineral dust aerosol: implications for tropospheric oxidation capacity

2017 ◽  
Author(s):  
Mingjin Tang ◽  
Xin Huang ◽  
Keding Lu ◽  
Maofa Ge ◽  
Yongjie Li ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Dust Aerosol ◽  
Heterogeneous Reactions ◽  
Dust Particles ◽  
Laboratory Studies ◽  
Research Strategies ◽  
Aerosol Composition ◽  
Oxidation Capacity ◽  
Open Questions ◽  
Modelling Studies

Abstract. Heterogeneous reactions of mineral dust aerosol with trace gases in the atmosphere could directly and indirectly affect tropospheric oxidation capacity, in addition to aerosol composition and physicochemical properties. In this article we provide a comprehensive and critical review of laboratory studies of heterogeneous uptake of OH, NO3, O3, and their directly related species as well (including HO2, H2O2, HCHO, HONO, and N2O5) by mineral dust particles. Atmospheric importance of heterogeneous uptake as sinks for these species are assessed (i) by comparing their lifetimes with respect to heterogeneous reactions with mineral dust to lifetimes with respect to other major loss processes and (ii) by discussing relevant field and modelling studies. We have also outlined major open questions and challenges in laboratory studies of heterogeneous uptake by mineral dust and discussed research strategies to address them in order to better understand the effects of heterogeneous reactions with mineral dust on tropospheric oxidation capacity.

scholarly journals An Overview of the Water Remediation Potential of Nanomaterials and Their Ecotoxicological Impacts

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1150 ◽  
Author(s):  
Mehrnoosh Ghadimi ◽  
Sasan Zangenehtabar ◽  
Shahin Homaeigohar
Keyword(s):  
Size Range ◽  
Current Knowledge ◽  
Field Studies ◽  
Water Systems ◽  
The Other ◽  
Water Remediation ◽  
One Dimension ◽  
Pros And Cons ◽  
New Generation ◽  
Soil And Water

Nanomaterials, i.e., those materials which have at least one dimension in the 1–100 nm size range, have produced a new generation of technologies for water purification. This includes nanosized adsorbents, nanomembranes, photocatalysts, etc. On the other hand, their uncontrolled release can potentially endanger biota in various environmental domains such as soil and water systems. In this review, we point out the opportunities created by the use of nanomaterials for water remediation and also the adverse effects of such small potential pollutants on the environment. While there is still a large need to further identify the potential hazards of nanomaterials through extensive lab or even field studies, an overview on the current knowledge about the pros and cons of such systems should be helpful for their better implementation.

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