Accumulation of Cyanobacteria Toxins in Lettuce and Radishes Exposed to Water and Aerosols from a Low-Toxin Lake

Cyanobacteria are the oldest known photosynthetic organisms on Earth. They are found in a wide range of habitats worldwide but have recently become an increasing issue in both freshwater and marine systems due to anthropogenic eutrophication and climate change. Cyanobacteria produce an array of toxins harmful to wildlife and humans, some of which have been found to accumulate in plant and animal tissues. Microcystins (MCs) are the most common toxins produced, occurring in 40 – 75% of cyanobacteria blooms worldwide. They are highly stable, water and fat soluble, cyclic heptapeptides that cause acute toxicity in the liver by the inhibition of cellular protein phosphatase 1 and 2a, resulting in the breakdown of hepatic tissues. MCs are also tumor promotors and have been linked with non-alcoholic liver disease with long-term exposure. β-methylamino-L-alanine (BMAA) is a non-protein coding amino acid that acts as a neurotoxin, is produced by all groups of cyanobacteria, and has been linked to neurodegenerative disorders such as Amyotrophic Lateral Sclerosis (ALS), Alzheimer’s, and Parkinson’s diseases. While many studies have reported the accumulation of MCs by various crop plants after exposure to high concentrations of toxin via irrigation water, relatively few studies have investigated such accumulation of BMAA, and none have investigated aerosolized cyanotoxins as a possible route of exposure. In this study, lettuce and radish seedlings were placed in hydroponic systems under small low-tunnels on the shore of Lake Attitash in Amesbury, MA and exposed to low levels of natural, lake-derived cyanotoxins in four treatments via lake water in the hydroponic reservoirs and deposited aerosols emitted from the lake. After three weeks, plant tissues were collected, separated, and analyzed for MCs and BMAA via Enzyme-Linked Immunosorbent Assay (ELISA) analysis. In a second experiment, particulate and dissolved fraction lake aerosols were collected in one open and one sealed/HEPA filtered tunnel using modified Compact-Lake-Aerosol-Monitors (CLAMs) to quantify aerosols emitted from Lake Attitash and to determine if aerosols had penetrated the filtered tunnel treatments. The average concentration of MCs and BMAA in water from Lake Attitash throughout the three-week experiment was 78.9 ng MC L-1 ± 7.06, and 350.0 ng BMAA L-1 ± 75.0. Lettuce plants had overall average dry weight MCs concentrations of 7.16 ± 0.38 ng g-1 in leaves, 5.65 ± 0.21 ng g-1 in stems, and 3.59 ± 0.77 ng g-1 in roots. Overall average MCs concentrations in radish tissues were 10.39 ± 1.20 ng g-1 in leaves, and 3.83 ± 0.23 ng g-1 in roots. BMAA concentrations displayed a similar trend, with dry weight concentrations of 7562.39 ± 1148.31 ng g-1 in lettuce leaves, 4018.54 ± 269.43 ng g-1 in lettuce stems, 551.88 ± 96.39 ng g-1 in lettuce roots, 4710.13 ± 490.27 ng g-1 in radish leaves, and 3223.60 ± 557.46 ng g-1 in radish taproots. This trend of higher toxin concentrations in the upper tissues of the plants is generally the opposite of what has been reported previously in the literature. CLAM samples collected in the early fall of 2017 had average particulate and dissolved MCs aerosol concentrations of 2.60 pg m-3 and 10.16 pg m-3, respectively, for an average total aerosol concentration of 12.76 pg m-3. The total average BMAA aerosol concentration was 1176.91 pg m-3, which was comprised of 630.86 pg m-3 dissolved and 546.05 pg m-3 particulate aerosols. This represents the first report of concurrent BMAA and MCs aerosols from the same water body, and one of the first reports on the concentration of BMAA in lake aerosols. Overall, there were few differences in toxin concentrations in each of the plants between treatments, and those that were present indicated that cyanotoxin aerosols were likely a significant source for accumulation in this system. Lettuce had significantly higher MCs and BMAA concentrations in the tissues exposed to aerosols (leaves and stems) compared to the roots, opposite the trend generally observed in the literature (Two-way ANOVA, n = 36, p \u3c 0.001). In addition, there were no significant differences between the lake water and tap water treatments for lettuce leaf and stem tissues (two-way ANOVA, n = 36, p = 0.068), though lettuce roots from the lake water treatments had a higher average MCs concentration than roots from the tap water treatments (one-way ANOVA, n = 12, p = 0.019). For radishes, the leaves from the open tunnel/tap water treatment had a higher MCs concentration than the other three treatments (two-way ANOVA, n = 12, p = 0.0037), and interestingly, the taproot tissues from the lake water treatments had a lower average MCs concentration than those from the tap water treatments (two-way ANOVA, n = 12, p = 0.036). In conclusion, this study demonstrated that accumulation of lake-derived cyanotoxins by crop plants can occur from lakes with relatively low levels of toxins, and that aerosols, especially the dissolved fraction, are likely playing an important role in the contamination of crops. However, further research on lake-derived cyanotoxin accumulation in crops via exposure to aerosols and irrigation water is needed to evaluate this potential risk for low-level, long term exposure to these toxins

Northerly Movement of Corn Borer Moths in Southern Minnesota

Seventeen light traps were installed in 6 counties in southwest Minnesota in 1962 and 1963 and the nightly catches of moths of the European corn borer were recorded. The results show that moth catch was higher during nights with south winds and the nights immediately following such nights. This relation occurred over a large area and during the entire flight period. Moth popu1\u27otion in southern Minnesota was increased when south winds prevailed during the Right period. The trapping and recording were carried out by 15 FFA members, l 4-H member, and l adult farmer. The project demonstrates that these young people represent a valuable pool of human resources for use in salving certain scientific problems

Towards democratic intelligence oversight: Limits, practices, struggles

Despite its common usage, The meaning of 'democratic' in democratic intelligence oversight has rarely been spelled out. In this paper, we situate questions regarding intelligence oversight within broader debates about the meanings and practices of democracy. We argue that the literature on intelligence oversight has tended to implicitly or explicitly follow liberal and technocratic ideas of democracy, which have limited the understanding of oversight both in academia and in practice. Thus, oversight is mostly understood as an expert, institutional and partially exclusive arrangement that is supposed to strike a balance between individual freedom and collective security with the goal of establishing the legitimacy of, and trust in intelligence work in a national setting. ‘Healthy’ or ‘efficient’ democratic oversight then becomes a matter of technical expertise, non-partisanship, and the ability to guard secrets. By analysing three moments of struggle around what counts as intelligence oversight across Germany, the UK, and the USA, this paper elucidates their democratic stakes. Through a practice-based approach, we argue that oversight takes much more agonistic, contentious, transnational, and public forms. However, these democratic practices reconfiguring oversight remain contested or contained by dominant views on what constitutes legitimate and effective intelligence oversight

Reprint of: CAA Broadband Noise Prediction for Aeroacoustic Design

AbstractThe current status of a hybrid RANS/CAA approach for the simulation of broadband sound generation is presented. The method rests on the use of steady Reynolds Averaged Navier-Stokes (RANS) simulation to prescribe the time-averaged motion of turbulent flow. By means of synthetic turbulence the steady one-point statistics (e.g. turbulent kinetic energy) and turbulent length- and time-scales of RANS are translated into fluctuations of turbulent velocity (or vorticity), whose statistics very accurately reproduce the spatial target distributions of RANS. The synthetic fluctuations are used to prescribe sound sources which drive linear acoustic perturbation equations. The whole approach represents a methodology to solve statistical noise theories with state-of-the-art Computational Aeroacoustics (CAA) tools in the time-domain. A brief overview of the synthetic turbulence model and its numerical discretization in terms of the Random Particle-Mesh (RPM) and Fast Random Particle-Mesh (FRPM) method is given. Results are presented for trailing edge, slat, jet, and combustion noise. Some problems related to the formulation of vortex sound sources are discussed

Conservação ambiental forte alcançada através de sistemas agroflorestais multiestratificados: 2 - restauração de paisagens degradadas por meio de agroflorestas.

Foi avaliada a sustentabilidade ambiental em nível da paisagem de práticas de sistemas agroflorestais multiestratificados na região do Vale do Ribeira, SP e PR, na escala da unidade de produção agrícola familiar, baseando-se nos resultados de várias pesquisas publicadas e em mapas georrefenciados de uso e ocupação do solo atual e histórico. As práticas da agrofloresta, através da indução de sucessão agroflorestal e da sucessão florestal secundária natural, resultam em uma paisagem produtiva sob intenso processo de restauração. Assim considera-se o ?land sharing? baseado em agroflorestas agroecológicas como uma promissora estratégia de conservação ambiental.Edição do 1º Seminário de Agroecologia da América do Sul; 5º Seminário de Agroecologia de Mato Grosso do Sul; 4º Encontro de Produtores Agroecológicos de Mato Grosso do Sul; 1º Seminário de Sistemas Agroflorestais em Bases Agroecológicas de Mato Grosso do Sul, 2014, Dourados, MS - AGROECOL

Functional Responses of South African Rangelands in Contrasting Tenure Systems

Land degradation in South African rangelands has frequently been studied in the context of tenure systems, because both governmental policy and range management practices were historically implemented in contrasting forms. We compared the functional response of vegetation along grazing gradients between a communal (CU) and commercial (CO) farming areas. One transect was established per farm from the waterpoint to a mid-field position. Six equally spaced plots (5 m × 5 m) were set up along each transect. Using a taxon-free sampling procedure, we recorded the response of 15 community-aggregated plant functional traits (CPFT) in: (1) mature standing biomass; and (2) after four weeks’ regrowth following clipping. Additionally, species identity was recorded. Grazing on CU was continuous and stocking rate not controlled, while CO applied rotational grazing with recommended stocking rates. From the results, CPFT differences were not significant (Student’s t-test, P \u3c 0.01) between tenure systems. A principal component analysis of CPFT showed largely overlapping functional responses in the two tenure systems in the case of mature standing biomass, while the functional response of regrowing vegetation was clearly separated in the ordination space. Communal rangelands had twice the species richness of commercial farms.We concluded that, from a functional perspective, communities under different tenure systems were similar. However, the functional response of vegetation regrowth might be different as well as the ecological services provided (biodiversity)

Threats for Global Food Supply of Increasing Surface Ozone - Spatial Assessment of Impacts and Adaptation Options

Surface ozone (O3) is a potent phytotoxic air pollutant and significantly reduces the productivity of important agricultural crops. Growing use of fossil fuel and changes in climate are increasing the global background surface ozone concentrations to levels that threaten regional and global food supply. We performed an integrated modeling study, considering biophysical and crop management factors, to identify the spatial pattern of ozone damage in lands suitable for crop cultivation and to assess the potential for adaptation for four key crops (wheat, maize, rice and soybean) under current and future air quality legislation. Results indicate that China, India and the United States are by far the most affected countries, bearing more than half of all global losses and threatened areas. Short-erm adaptive measures at farm level, such as shifting crop calendars (by changing sowing dates or using crop cultivars with different cycle lengths) can reduce ozone damage regionally but have only limited impact at the global level. Considering these limited benefits of adaptation, mitigation of O3 precursors remains the main option to secure regional and global food production

Contesting authentic practice and ethical authority in adventure tourism

This paper examines the discourses of authenticity and ethics used among adventure tourists regarding the use of the natural environment. In one case, full-time traveling rock climbers use their dedication to the sport and annual visits to the Red River Gorge as evidence for their authoritative voice on ethical climbing practice. While they identify the growing numbers of leisure climbers as a problem for sustainability, many also take up temporary employment as guides and are directly involved in the introduction of new climbers to the area. In another case, two groups of wilderness enthusiasts – “ADK 46ers” and “Summit Stewards” – lament the environmental and social impacts of other recreational users in the Adirondack Park. Despite being visitors themselves, Summit Stewards and 46ers use their sense of place and knowledge of Adirondack history and ecology to substantiate their authority as purveyors of ethical practice. In both cases, senses of responsibility are inspired by senses of place, but are articulated through notions of authenticity and used as justification for ethical authority. While validating their presence in these outdoor spaces, the use of such rhetoric also minimizes their own impacts yielding further tensions among user groups