The impact of the Antarctic Ozone Hole Influence over Southern Brazil in October 2015 was analyzed using daily mean data of the Total Column Ozone (TCO), Ultraviolet Index (UVI) and Radiative Cloud ...Fraction (RCF) from the Ozone Monitoring Instrument satellite instrument. Vertical profiles and fields of ozone content and Potential Vorticity available from the European Centre for Medium-Range Weather Forecast reanalysis, air masses backward trajectories from the HYbrid Single-Particle Lagrangian Integrated Trajectory model and channel 3 water vapor images from the Geostationary Operational Environmental Satellite GOES-13 were also analyzed. The five identified events showed an -7.4±2.3% average TCO reduction, leading to an +16.6±54.6% UVI increase even with a predominance of partly cloudy days. Other impacts were observed in the ozone profiles, where the most significant anomalies occurred from 650 K reaching 1.2 ppmv at the 850 K level. In the ozone fields at 700 K, the presence of a polar origin tongue was observed causing negatives anomalies between -0.2 and 0.4 ppmv in a transient system format forced with eastward-traveling Rossby waves passing through the Southern of Brazil and Uruguay.
The analysis of gross primary production (GPP) is crucial to better understand CO2 exchanges between terrestrial ecosystems and the atmosphere, while the quantification of water-use efficiency (WUE) ...allows for the estimation of the compensation between carbon gained and water lost by the ecosystem. Understanding these dynamics is essential to better comprehend the responses of environments to ongoing climatic changes. The objective of the present study was to analyze, through AMERIFLUX and LBA network measurements, the variability of GPP and WUE in four distinct tropical biomes in Brazil: Pantanal, Amazonia, Caatinga and Cerrado (savanna). Furthermore, data measured by eddy covariance systems were used to assess remotely sensed GPP products (MOD17). We found a distinct seasonality of meteorological variables and energy fluxes with different latent heat controls regarding available energy in each site. Remotely sensed GPP was satisfactorily related with observed data, despite weak correlations in interannual estimates and consistent overestimations and underestimations during certain months. WUE was strongly dependent on water availability, with values of 0.95 gC kg−1 H2O (5.79 gC kg−1 H2O) in the wetter (drier) sites. These values reveal new thresholds that had not been previously reported in the literature. Our findings have crucial implications for ecosystem management and the design of climate policies regarding the conservation of tropical biomes, since WUE is expected to change in the ongoing climate change scenario that indicates an increase in frequency and severity of dry periods.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Nowadays, the study of the upper atmosphere is increasing, mostly because of
the need to understand the patterns of Earth's atmosphere. Since studies on
global warming have become very important for ...the development of new
technologies, understanding all regions of the atmosphere becomes an
unavoidable task. In this paper, we aim to analyze the temperature
variability and its trend in the mesosphere and lower thermosphere (MLT)
region during a period of 12 years (from 2003 to 2014). For this purpose,
three different heights, i.e., 85, 90 and 95 km, were focused on in order to
investigate the upper atmosphere, and a geographic region different to other
studies was chosen, in the southern region of Brazil, centered in the city of
Santa Maria, RS (29∘41′02′′ S; 53∘48′25′′ W). In
order to reach the objectives of this work, temperature data from the SABER
instrument (Sounding of the Atmosphere using Broadband Emission Radiometry),
aboard NASA's Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED)
satellite, were used. Finally, two cases were studied related to distinct
grids of latitude/longitude used to obtain the mean temperature profiles. The
first case considered a grid of 20∘ × 20∘ lat/long,
centered in Santa Maria, RS, Brazil. In the second case, the region was
reduced to a size of 15∘ × 15∘ in order to compare
the results and discuss the two cases in terms of differences or similarities
in temperature trends. Observations show that the size of the geographical
area used for the average temperature profiles can influence the results of
variability and trend of the temperature. In addition, reducing the time
duration of analyses from 24 to 12 h a day also influences the trend
significantly. For the smaller geographical region
(15∘ × 15∘) and the 12 h daily time window
(09:00–21:00 UT) it was found that the main contributions for the
temperature variability at the three heights were the annual and semi-annual
cycles and the solar flux influence. A smaller trend
(−0.02 ± 0.16 % decade−1) was found at 90 km height and
small positive trends (0.58 ± 0.26 % and
0.41 ± 0.19 % decade−1) were found at altitudes of 85 and
95 km, respectively.. Keywords. Atmospheric composition and structure (middle atmosphere – composition and chemistry; pressure, density, and temperature) – meteorology and atmospheric dynamics (climatology)
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Summary
Background
Trichophyton rubrum (Tr) is the main aetiological agent of human dermatophytosis, being isolated from the environment and keratinised tissues. In the environment, Tr can interact ...with other organisms, such as free‐living amoebas (FLA), which can act as an alternative host system to study the interaction between microbes and phagocytic cells.
Objectives
To characterise the Acanthamoeba castellanii (ALX)‐Tr interaction.
Methods
Interaction was characterised in three conditions: trophozoites (PYG), late (PYG/NES) and early (NES) encystation stimulus, evaluating encystation kinetics, phagocytosis, exocytosis and fungicidal activity dynamics.
Results
Tr was able to induce ALX encystation and be internalised by ALX. The number of internalised conidia was high at 1 hour, and ALX presented fungicidal activity with increased intracellular ROS production and exocytosis. In PYG/NES, phagocytosis and ROS production were reduced, with decreased ALX’s fungicidal activity. However, in NES there was an increased fungal engulfment, and a reduced ROS production and higher fungal burden. Furthermore, exogenous mannose decreased phagocytosis of Tr conidia, and divalent cations induced ROS production and increased ALX’s fungicidal activity. Interestingly, phagocytosis was reduced in the presence of cytoskeleton inhibitor, but exocytosis was increased, suggesting that Tr conidia may have alternative pathways to escape ALX's cells.
Conclusion
A castellanii is a proper model for studying Tr‐FLA interaction, since ALX can engulf, produce ROS and kill Tr, and all these parameters are influenced by an encystation stimulus and divalent cations. Moreover, this interaction is likely to occur in the environment implicating in the adaptation to environmental stressful conditions in both organisms.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
In this study, two by-products resulting from the processing of cherry (stems and pits) were used as natural coagulants to promote the valorization of these wastes and treat olive mill wastewater ...(OMW). The efficacy of the plant-based coagulants (PBCs) in the coagulation–flocculation–decantation process (CFD) was evaluated through the removal of turbidity, total suspended solids (TSS), total polyphenols (TPh), and dissolved organic carbon (DOC). The CFD process was demonstrated to be effective in turbidity and TSS reduction in OMW. Using cherry stems (CSs), these reductions were 65.2% of turbidity and 58.0% of TSS, while cherry pits (CPs) achieved higher reductions, 78.6% of turbidity and 68.2% of TSS. To improve the effectiveness of OMW treatment, mainly regarding the removal of TPh and DOC, the CFD process was complemented with the adsorption process (using bentonite clay). The adsorption capacity of bentonite was higher in acidic conditions (pH 3.0) and, with a dosage of 3.0 g L−1, reached 17.3 mg of DOC and 13.8 mg of TPh per gram of bentonite. Several adsorption isothermal models were assessed, and the Langmuir (r2 = 0.985), SIPS (r2 = 0.992), and Jovanovic models (r2 = 0.994) provided the best fittings. According to the optimal operational conditions defined throughout the present work, the combination of CFD and adsorption removals were as follows: (1) 98.0 and 91.3% of turbidity, (2) 80.8 and 81.2% of TSS, (3) 98.1 and 97.6% of TPh and (4) 57.9 and 62.2% of DOC, for CSs and CPs, correspondingly. Overall, the results suggest that cherry by-products can be used as low-cost natural coagulants and, when combined with another natural, abundant, and cheap material, such as bentonite clay, can be a sustainable alternative for treating OMW.
Trichomes are epidermal structures with a large variety of ecological functions and economic applications. Glandular trichomes produce a rich repertoire of secondary metabolites, whereas ...non-glandular trichomes create a physical barrier on the epidermis: both operate in tandem against biotic and abiotic stressors. A deeper understanding of trichome development and function would enable the breeding of more resilient crops. However, little is known about the impact of altered trichome density on leaf photosynthesis, gas exchange and energy balance. Previous work has compared multiple, closely related species differing in trichome density. Here, we analysed monogenic trichome mutants in the same tomato genetic background (Solanum lycopersicum cv. ‘Micro-Tom’). We determined growth parameters, leaf spectral properties, gas exchange and leaf temperature in the hairs absent (h), Lanata (Ln) and Woolly (Wo) trichome mutants. Shoot dry weight, leaf area, leaf spectral properties and cuticular conductance were not affected by the mutations. However, the Ln mutant showed increased net carbon assimilation rate (An), associated with higher stomatal conductance (gs), with no differences in stomatal density or stomatal index between genotypes. Leaf temperature was furthermore reduced in Ln in the hottest, early hours of the afternoon. We show that a single monogenic mutation that modifies trichome density, a desirable trait for crop breeding, concomitantly improves leaf gas exchange and reduces leaf temperature.
Full text
Available for:
GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The Antarctic ozone hole (AOH) directly influences the Antarctic
region, where its levels can reach values below 220 DU. The temporary
depletion of ozone in Antarctica generally occurs between the ...beginning and
middle of August, during the austral spring, and extends to November, when a
temporary reduction in ozone content is observed in a large region over the
Antarctic continent. However, masses of ozone-depleted air can break away
from the ozone hole and reach mid-latitude regions in a phenomenon known
as the secondary effect of the Antarctic ozone hole. The objective of this
paper is to show how atmospheric dynamics behave during the occurrence of
this type of event, especially in mid-latitude regions, such as southern
Brazil, over a 12-year observation period. For the analysis and
identification of the events of influence of the AOH on the southern region
of Brazil, data from the total ozone column were used from ground-based and
satellite experiments, the Brewer Spectrophotometer (MkIII no. 167), and the
Ozone Monitoring Instrument (OMI) on the Aura satellite. For the analysis of
the stratospheric and tropospheric fields, the ECMWF reanalysis products
were used. Thus, 37 events of influence of the AOH that reached the southern
region of Brazil were identified for the study period (2006–2017), where the
events showed that in approximately 70 % of the cases they occurred after
the passage of frontal systems and/or atmospheric blocks over southern
Brazil. In addition, the statistical analysis showed a strong influence of
the jet stream on mid-latitude regions during the events. Among the 37
identified events, 92 % occurred in the presence of the subtropical and/or
polar jet stream over the region of study, possibly explaining the exchange
of air masses of ozone deficient in the upper troposphere–lower
stratosphere (UT–LS) region.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Ozone is one of the chemical compounds that form part of the atmosphere. It
plays a key role in the stratosphere where the “ozone layer” is located and
absorbs large amounts of ultraviolet radiation. ...However, during austral
spring (August–November), there is a massive destruction of the ozone layer,
which is known as the “Antarctic ozone hole”. This phenomenon decreases
ozone concentration in that region, which may affect other regions in
addition to the polar one. This anomaly may also reach mid-latitudes; hence,
it is called the “secondary effect of the Antarctic ozone hole”. Therefore,
this study aims to identify the passage of an ozone secondary effect (OSE)
event in the region of the city of Santa Maria – RS (29.68∘ S,
53.80∘ W) by means of a multi-instrumental analysis using the
satellites TIMED/SABER, AURA/MLS, and OMI-ERS. Measurements were made in
São Martinho da Serra/RS – Brazil (29.53∘ S, 53.85∘ W)
using a sounding balloon and a Brewer Spectrophotometer. In addition, the
present study aims to describe and analyse the influence that this
stratospheric ozone reduction has on temperatures presented by these
instruments, including data collected through the radio occultation
technique. The event was first identified by the AURA/MLS satellite on
19 October 2016 over Uruguay. This reduction in ozone concentration was found
by comparing the climatology for the years 1996–1998 for the state of Rio
Grande do Sul, which is close to Uruguay. This event was already observed in
Santa Maria/RS-Brazil on 20 October 2016 as presented by the OMI-ERS
satellite and the Brewer Spectrophotometer. Moreover, a significant decrease
was reported by the TIMED/SABER satellite in Uruguay. On 21 October, the poor
ozone air mass was still over the region of interest, according to the
OMI-ERS satellite, data from the sounding balloon launched in Santa
Maria/RS-Brazil, and measurements made by the AURA/MLS satellite.
Furthermore, the influence of ozone on the stratosphere temperature was
observed during this period. Despite a continuous decrease detected in
height, the temperature should have followed an increasing pattern in the
stratospheric layer. Finally, the TIMED/SABER and OMI-ERS satellites showed
that on 23 October, the air mass with low ozone concentration was moving
away, and its layer, as well as the temperature, in the stratosphere was
re-established. Keywords. Atmospheric composition and structure (middle atmosphere – composition and chemistry; instruments and techniques)
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The Antarctic ozone hole is a cyclical phenomenon that occurs
during the austral spring where there is a large decrease in ozone content in
the Antarctic region. Ozone-poor air mass can be released ...and leave through
the Antarctic ozone hole, thus reaching midlatitude regions. This phenomenon
is known as the secondary effect of the Antarctic ozone hole. The objective
of this study is to show how tropospheric and stratospheric dynamics behaved
during the occurrence of this event. The ozone-poor air mass began to operate
in the region on 20 October 2016. A reduction of ozone content of
approximately 23 % was observed in relation to the climatology average
recorded between 1992 and 2016. The same air mass persisted over the region
and a drop of 19.8 % ozone content was observed on 21 October. Evidence
of the 2016 event occurred through daily mean measurements of the total ozone
column made with a surface instrument (Brewer MkIII no. 167
Spectrophotometer) located at the Southern Space Observatory
(29.42∘ S, 53.87∘ W) in São Martinho da Serra, Rio Grande do Sul.
Tropospheric dynamic analysis showed a post-frontal high pressure system on
20 and 21 October 2016, with pressure levels at sea level and thickness between 1000
and 500 hPa. Horizontal wind cuts at 250 hPa and omega values at 500 hPa revealed
the presence of subtropical jet streams. When these streams were allied with
positive omega values at 500 hPa and a high pressure system in southern Brazil and Uruguay, the advance of the ozone-poor air mass that caused
intense reductions in total ozone content could be explained. Keywords. Atmospheric composition and structure (middle atmosphere – composition and chemistry)
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The fragmentation and habitat loss are the main causes of pollinators decline worldwide, however very little is known about the composition and distribution of neotropical pollinators along ...continuous micro-environments. To fill this gap, we carried out samplings of Euglossini bees in a continuous area of forest with micro-environments of primary (remnant) and secondary (regeneration) forest of Atlantic Forest. We evaluated the differences in the composition and uniformity of orchid bees in different micro-environments, in order to characterize the responses of the local environmental changes in the attraction of bees to chemical traps. Our results indicated that the composition and uniformity were similar between the two forest fragments studied here, although there are greater abundance of some species by micro-environments. We conclude that the characteristics of the sites in a continuous environment with primary and secondary forest do not seem to have an effect on the composition of the Euglossini fauna, and that the chemical substances are complementary in the attractiveness of the orchid bee males. Thus, our findings suggest that micro-environments in a continuous matrix near forest remnants can help to promote the reintegration of the orchid bee communities and contribute to the conservation of areas in process of forest regeneration.
PDF
