Effects of drought conditions on VOC soil fluxes within the rainforest mesocosm of Biosphere 2

2021 ◽  
Author(s):  
Giovanni Pugliese ◽  
Johannes Ingrisch ◽  
Thomas Klüpfel ◽  
Kathiravan Meeran ◽  
Gemma Purser ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Uv Light ◽  
Soil Microbial Activity ◽  
Oxidation Products ◽  
Severe Drought ◽  
Molecular Formula ◽  
Drought Period ◽  
Biosphere 2 ◽  
Drought Conditions ◽  
Mild Drought

<p>Volatile organic compounds (VOC) play an important role in determining atmospheric processes that control air quality and climate. Although atmospheric VOC concentrations are mostly affected by plants, soils are significant contributors as they are simultaneously a source, a sink and a storage of atmospheric VOCs. The aim of the present study was to assess the effects of a prolonged drought condition on VOC soil fluxes in the tropical rainforest mesocosm of Biosphere 2 (B2; Tucson, Arizona, USA). The absence of atmospheric chemistry due to UV light filtering by the glass and the possibility to control and manipulate the conditions of the ecosystem make the B2 an ideal set-up to study the rainforest VOC dynamics.</p><p>The experiments were conducted over the 4 months B2WALD campaign during which the rainforest was subjected to a controlled drought period of about 10 weeks followed by a rewetting period. Soil VOCs fluxes were measured continuously by means of a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) that was connected to 12 automated soil chambers (LI 8100-104 Long-Term Chambers, Licor Inc.) placed in 4 different locations within the B2 rainforest.</p><p>The B2 rainforest soil acted as a strong sink for all isoprenoid species. The isoprene sink steadily weakened during drought period, but increased sharply back to the pre-drought levels after the rain rewet. In contrast, the monoterpene soil sink became slightly stronger during the mild drought period (up to 5 weeks after the last rainfall) but weakened during the severe drought period (up to 10 weeks after rainfall). A huge increase in monoterpene uptake was observed after the rain rewet. The oxidation products of isoprene (methacrolein, methyl vinyl ketone and isoprene peroxides) showed a similar trend to the monoterpenes, even in absence of atmospheric chemistry. The species with molecular formula C5H8O was taken up by the soil during predrought, which was reduced during mild drought period but increased again during the severe drought period.Sulfur-containing compounds including DMS and methanethiol all showed a significant emission peak immediately after the rain rewet.Oxygenated VOCs such as methanol and acetone were taken up by the soil in wet conditions. The uptake of both compounds strongly decreased with the drought and in severe drought conditions they were even emitted by the soil.</p><p>In summary, soil VOC fluxes changed markedly with the onset and development drought stages (pre, mild and severe drought) of the B2 rainforest, mirroring atmospheric VOC concentrations and soil microbial activity changes related to overall ecosystem response to drought and recovery.</p>

scholarly journals The impact of drought on total ozone flux in a mountain Norway spruce forest

2020 ◽  
Vol 66 (No. 7) ◽  
pp. 280-278 ◽  
Author(s):  
Thomas Agyei ◽  
Stanislav Juráň ◽  
Kojo Kwakye Ofori-Amanfo ◽  
Ladislav Šigut ◽  
Otmar Urban ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Stomatal Closure ◽  
Severe Drought ◽  
Summer Drought ◽  
Spruce Forest ◽  
Soil Humidity ◽  
Drought Period ◽  
The Impact ◽  
Mild Drought ◽  
Norway Spruce Forest

In order to understand the impact of summer drought on dry deposition of tropospheric ozone (O<sub>3</sub>), we compared severe and mild drought periods of summer 2018 in a mountain Norway spruce forest at Bílý Kříž, Beskydy Mts. An eddy covariance technique was applied to measure diurnal courses of the ecosystem O<sub>3</sub> and CO<sub>2</sub> fluxes. Low O<sub>3</sub> deposition was recorded in the morning and evening, while the highest CO<sub>2</sub> and O<sub><sup>3</sup></sub> fluxes were recorded during the central hours of the day. Total O<sub>3</sub> deposition during severe drought (soil humidity 13%) was significantly higher than the deposition during the mild drought period (soil humidity 19%). Our data indicate that high vapour pressure deficit and low soil humidity during severe drought led to the stomatal closure, while non-stomatal O<sub>3</sub> deposition, associated with chemical reactions of O<sub>3</sub> with NO and volatile organic compounds, are responsible for higher total O<sub>3</sub> deposition during the severe drought period. Therefore, we assume that under severe drought stomatal O<sub>3</sub> uptake decreases but non-stomatal depositions to forest ecosystems substantially increase.

Drought effects on the carbon balance and VOC emissions of a tropical rainforest ecosystem

2020 ◽  
Author(s):  
Ines Bamberger ◽  
Lars Erik Daber ◽  
Juliana Gil Loaiza ◽  
Gemma Purser ◽  
Jason De Leeuw ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Stress Responses ◽  
Carbon Balance ◽  
Leaf Gas Exchange ◽  
Life Time ◽  
Proton Transfer Reaction ◽  
Plant Signaling ◽  
Tropical Ecosystems ◽  
Drought Period ◽  
Biosphere 2

&lt;p&gt;Trees contribute substantially to the carbon cycling between the biosphere and atmosphere. Tropical ecosystems in particular are known to exchange not only CO&lt;sub&gt;2&lt;/sub&gt; with the atmosphere, but also a wide variety of volatile organic compounds (VOCs). With their high reactivity and short life time, VOCs are known to play not only a crucial role in atmospheric chemistry but also in plant signaling and interactions. Due to climate change periods of sustained drought are thought to increase in future and have the potential to alter the carbon balance of tropical ecosystems drastically. However, combined VOC and CO&lt;sub&gt;2&lt;/sub&gt; flux measurements are rare and thus a quantitative understanding of carbon exchange fluxes in rainforest species during and after drought periods has not yet been reached.&lt;/p&gt;&lt;p&gt;Thus, we used the unique opportunity to study changes of VOC and CO&lt;sub&gt;2&lt;/sub&gt; flux patterns of the rainforest mesocosm of Biosphere 2 (University of Arizona) in response to an experimentally induced drought period and during the recovery (Biosphere 2 Water, Atmosphere, and Life Dynamics experiment; B2-WALD). This provides us novel information about stress responses of a rainforest ecosystem and its ability to recover, specifically to drought stress. Real-time fluxes of CO&lt;sub&gt;2&lt;/sub&gt; and VOC exchange were measured by means of &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; laser spectroscopy and proton-transfer-reaction time-of-flight mass-spectrometry (PTR-TOF-MS) using leaf chambers on five different tree and understory species.&lt;/p&gt;&lt;p&gt;While photosynthesis decreased during the drought, changes in VOC flux patterns were more diverse. For example, isoprene emissions increased with dry conditions, whereas fluxes of acetone declined. Here we will present and discuss our first results on leaf gas exchange measurements of different VOCs and CO&lt;sub&gt;2&lt;/sub&gt; and their response to drought and recovery.&lt;/p&gt;

scholarly journals Identifying the Drought Impact Factors and Developing Drought Scenarios using the DSD Model

2021 ◽  
Author(s):  
Soyeon Lim ◽  
Donghwi Jung
Keyword(s):  
Water Resources ◽  
Impact Factor ◽  
Water Demand ◽  
Temporal Variability ◽  
Impact Factors ◽  
Severe Drought ◽  
Drought Period ◽  
Drought Impact ◽  
Drought Conditions ◽  
Effective Policy

Abstract Due to climate change, droughts have become increasingly severe and frequent. Droughts do not simply create water scarcity but also various socio-economic issues. Therefore, it is necessary to manage droughts on the government level through water resource management policies that consider drought conditions. The drought characteristics within each administrative division need to be closely analyzed for effective policy. In this study, a drought impact factor analysis using the DSD model was presented as a method. Through the relationship between various hydrometeorological factors and drought index, the drought impact factor was identified for each area. For South Korea, meteorological factors have a greater impact on droughts than hydrological factors. Identified drought impact factors are analyzed depending on spatio-temporal variability to recognize the features in various aspects of droughts. For the temporal variability, water demand change and severe drought period are considered. Also, for the spatial variability, based on the type of water demand, administrative divisions are grouped into four zones and analyzed accordingly. Finally, a drought scenario based on identified drought impact factor was constructed to present the probable drought conditions in the future. Components of drought scenario reflect the organization of water resources within an area and it combine the each level of components. Through the constructed drought scenarios, it is possible to establish an effective policy for managing water resources considering the drought condition.

scholarly journals Analysis of Whole Transcriptome RNA-seq Data Reveals Many Alternative Splicing Events in Soybean Roots under Drought Stress Conditions

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1520
Author(s):  
Li Song ◽  
Zhenzhi Pan ◽  
Lin Chen ◽  
Yi Dai ◽  
Jinrong Wan ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Drought Stress ◽  
Drought Response ◽  
Severe Drought ◽  
Ontology Term ◽  
Soybean Root ◽  
A Genome ◽  
Drought Conditions ◽  
Soybean Roots ◽  
Mild Drought

Alternative splicing (AS) is a common post-transcriptional regulatory mechanism that modulates gene expression to increase proteome diversity. Increasing evidence indicates that AS plays an important role in regulating plant stress responses. However, the mechanism by which AS coordinates with transcriptional regulation to regulate drought responses in soybean remains poorly understood. In this study, we performed a genome-wide analysis of AS events in soybean (Glycine max) roots grown under various drought conditions using the high-throughput RNA-sequencing method, identifying 385, 989, 1429, and 465 AS events that were significantly differentially spliced under very mild drought stress, mild drought stress, severe drought stress, and recovery after severe drought conditions, respectively. Among them, alternative 3′ splice sites and skipped exons were the major types of AS. Overall, 2120 genes that experienced significant AS regulation were identified from these drought-treated root samples. Gene Ontology term analysis indicated that the AS regulation of binding activity has vital roles in the drought response of soybean root. Notably, the genes encoding splicing regulatory factors in the spliceosome pathway and mRNA surveillance pathway were enriched according to the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Splicing regulatory factor-related genes in soybean root also responded to drought stress and were alternatively spliced under drought conditions. Taken together, our data suggest that drought-responsive AS acts as a direct or indirect mode to regulate drought response of soybean roots. With further in-depth research of the function and mechanism of AS in the process of abiotic stress, these results will provide a new strategy for enhancing stress tolerance of plants.

How do lichens survive severe drought conditions?

Mycologist ◽  
1996 ◽  
Vol 10 (2) ◽  
pp. 89-90
Author(s):  
Susan Isaac
Keyword(s):  
Severe Drought ◽  
Drought Conditions

The Bolivian Drought Monitor: an operational tool, calibrated on impact records, to identify and communicate drought severity conditions.

2021 ◽  
Author(s):  
Lauro Rossi ◽  
Alessandro Masoero ◽  
Anna Mapelli ◽  
Fabio Castelli
Keyword(s):  
Remote Sensing ◽  
Early Warning ◽  
Warning System ◽  
Drought Severity ◽  
Severe Drought ◽  
Drought Event ◽  
Context Analysis ◽  
Management Platform ◽  
Drought Conditions ◽  
Civil Defence

&lt;p&gt;Within the framework of the CIF financed &amp;#8220;Pilot Program for Climate Resilience&amp;#8221;, the Drought Monitoring and Early Warning System for Bolivia was developed and implemented. The system is operational since July 2020 and aims at detecting emerging severe drought conditions in the country, in order to trigger timely warnings to stakeholders and the general public.&lt;/p&gt;&lt;p&gt;The Bolivian Drought Monitor has two main components: a technical one (data gathering and analysis, performed through the multi-hazard early warning &amp;#8220;myDEWETRA&amp;#8221; platform) and an institutional one (creating consensus and disseminating warnings). The system design followed a participatory approach, involving since the early stages the Ministry for Water and Environment (MMAyA), the National Hydrometeorological Service (SENAMHI), the Vice-Ministry for Civil Defence (VIDECI). These institutions actively contribute to the monthly edition of the drought bulletin, each one for its own sector of competence, through a dedicated IT tool for synchronous compilation. Ongoing drought conditions are reported in a national bulletin, issued monthly and published on a dedicated public website: http://monitorsequias.senamhi.gob.bo/&lt;/p&gt;&lt;p&gt;Given the Bolivian data-poor context, analysis strongly relies on a large variety of multi-source satellite products, spanning from well consolidated ones in the operational practice to more experimental ones such as from the SMAP mission. This information is used to monthly refresh the spatial maps of 17 indexes covering meteorological, hydrological and agricultural droughts for different aggregation periods (from 1 to 12 months). Simulation of the system performance over a long period (2002-2019) and comparison with recorded socio-economic drought impacts&amp;#160; from the National Disaster Observatory (Observatorio Nacional de Desastres- OND) of the Vice-Ministry of Civil Defence (VIDECI) was used to define a most representative compound index, based on a weighted combination of a selection of 4 indexes with their related thresholds. The combination of 3-month SPEI, 2-month SWDI, 1-month VHI and 1-month FAPAR indexes performed the best in the comparison with impact records. This combination encompasses both the medium-term effects of meteorological and hydrological deficits (3-month SPEI and SWDI), both the short-term effects on vegetation (1-month VHI and FAPAR). This set of indexes proved to be a solid proxy in estimating possible impacts on population of ongoing or incoming drought spells, as happened for most significant recent drought events occurred in Bolivia, such as the 2010 event in the Chaco region and the 2016 drought event in the Altiplano and Valles regions, that heavily affected the water supply in several major cities (La Paz, Sucre, Cochabamba, Oruro and Potos&amp;#237;).&lt;/p&gt;&lt;p&gt;The design of the monitoring and bulletin management platform, together with its strong remote-sensing base, give to the system a high potential for easy export to other regional and national contexts. Also, the variety of the different computed drought indexes and the replicability of the procedure for the best compound index identification will allow for efficient evolutionary maintenance as new remote-sensing products will be available in the future.&lt;/p&gt;

scholarly journals Invasive Plants and Climate Change Will Alter Desert Landscapes

Eos ◽  
2022 ◽  
Vol 103 ◽  
Author(s):  
Katherine Kornei
Keyword(s):  
Climate Change ◽  
Invasive Plants ◽  
Biosphere 2 ◽  
Drought Conditions ◽  
Better Than

In experiments conducted in Biosphere 2, invasive buffelgrass weathers higher temperatures and drought conditions better than its native brethren.

scholarly journals Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elsayed Mansour ◽  
Hany A. M. Mahgoub ◽  
Samir A. Mahgoub ◽  
El-Sayed E. A. El-Sobky ◽  
Mohamed I. Abdul-Hamid ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Severe Drought ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

scholarly journals Rapid formation of isoprene photo-oxidation products observed in Amazonia

2009 ◽  
Vol 9 (3) ◽  
pp. 13629-13653 ◽  
Author(s):  
T. Karl ◽  
A. Guenther ◽  
A. Turnipseed ◽  
P. Artaxo ◽  
S. Martin
Keyword(s):  
Atmospheric Chemistry ◽  
Global Climate ◽  
Oxidative Capacity ◽  
Oxidation Products ◽  
Lower Atmosphere ◽  
Peroxy Radicals ◽  
Aerosol Formation ◽  
Photo Oxidation ◽  
Voc Oxidation ◽  
Rapid Formation

Abstract. Isoprene represents the single most important reactive hydrocarbon for atmospheric chemistry in the tropical atmosphere. It plays a central role in global and regional atmospheric chemistry and possible climate feedbacks. Photo-oxidation of primary hydrocarbons (e.g. isoprene) leads to the formation of oxygenated VOCs (OVOCs). The evolution of these intermediates affects the oxidative capacity of the atmosphere (by reacting with OH) and can contribute to secondary aerosol formation, a poorly understood process. An accurate and quantitative understanding of VOC oxidation processes is needed for model simulations of regional air quality and global climate. Based on field measurements conducted during the Amazonian aerosol characterization experiment (AMAZE-08) we show that the production of certain OVOCs (e.g. hydroxyacetone) from isoprene photo-oxidation in the lower atmosphere is significantly underpredicted by standard chemistry schemes. A recently suggested novel pathway for isoprene peroxy radicals could explain the observed discrepancy and reconcile the rapid formation of these VOCs. Furthermore, if generalized our observations suggest that prompt photochemical formation of OVOCs and other uncertainties in VOC oxidation schemes could result in substantial underestimates of modelled OH reactivity that could explain a major fraction of the missing OH sink over forests which has previously been attributed to a missing source of primary biogenic VOCs.

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