scholarly journals Using Capacitance Sensors for the Continuous Measurement of the Water Content in the Litter Layer of Forest Soil

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Mioko Ataka ◽  
Yuji Kominami ◽  
Takafumi Miyama ◽  
Kenichi Yoshimura ◽  
Mayuko Jomura ◽  
...  
Keyword(s):  
Water Content ◽  
Output Voltage ◽  
Continuous Measurement ◽  
Calibration Line ◽  
Calibration Function ◽  
Litter Layer ◽  
Wetting And Drying ◽  
Study Sites ◽  
Water Holding

Little is known about the wetting and drying processes of the litter layer (Llayer), likely because of technical difficulties inherent in nondestructive water content (WC) monitoring. We developed a method for continuously measuring the WC of leaf litter (the “LWC method”)in situusing capacitance sensors. To test variants of this approach, five (for the LWC_5) or ten (for the LWC_10 method)Quercus serrataleaves were attached around capacitance sensors. The output voltage used for each LWC method was linearly correlated with the gravimetric WC (LWC_5:R2=0.940; LWC_10:R2=0.942), producing different slopes for each calibration line. Forin situcontinuous measurements of WC in theLlayer, two sensors were used, one placed on top of theLlayer and the other at the boundary between theLand mineral layers. The average continuous WC of theLlayer was then calculated from the output voltage of the two sensors and the calibration function, and this value was linearly correlated with the gravimetric WC(R2=0.697). However, because theLlayer characteristics (e.g., thickness, water-holding capacity, and species composition) may differ among study sites, appropriate approaches for measuring this layer’s moisture properties may be needed.

Peatland hydrological behavior with global warming

2020 ◽  
Author(s):  
Stefano Ferraris ◽  
Davide Canone ◽  
Davide Gisolo ◽  
Mario Putti ◽  
Pietro Teatini ◽  
...  
Keyword(s):  
Global Warming ◽  
Water Content ◽  
Peat Soil ◽  
Time Domain Reflectometry ◽  
Peat Deposit ◽  
Complete Disappearance ◽  
Matric Potential ◽  
Wetting And Drying ◽  
Possible Cause

<p>A peat deposit close to Venice was monitored both in the field and in the lab (1) to investigate the hydrological response of peat soil to changing meteorological conditions in the frame of land subsidence assessment. The whole area is about 3 meters lower than the sea level and therefore subsidence is a major issue. Predictions highlighted the risk of an almost complete disappearance of the peat layer in this area during the next 50 years, due to the increased frequency of warmer periods. Unfortunately, despite the considerable impacts that are expected to affect peatland worldwide, only a few measured datasets are currently available to assess the response of a peat deposit to enhanced drying due to global warming.</p><p>The lab measurements were performed both at the pedon and at the core scale. An undisturbed peat monolith of approximately 0.7 m<sup>3</sup> was collected, transferred to the lab, and instrumented to monitor matric potential, water content, and total weight. This undisturbed peat lysimeter allows to monitor water content variations (both through the weight monitoring and time domain reflectometry sensors), and matric potential, with drier conditions with respect to the field campaign. A complete cycle of wetting and drainage was performed, raising the water table from the bottom to the top of the sample and down again. Additional measurements of matric potential and water content were collected by testing peat cores on a suction table.</p><p>A set of water retention curves was experimentally determined. They were derived for a range of  matric potential much broader than that experienced in situ . Variations were found, with respect to the field natural conditions, in the relations between the matric potential and the volumetric water content of different horizons as a result of the initial prolonged drying. Also, the hysteresis behaviours in the lab and in the field were different, with much wider loops in the lab conditions because of extended range of potential. Hydraulic non-equilibrium between the water content and water potential could also  be a possible cause, but further modelling work is necessary to assess it. The van Genuchten parameters were obtained for both wetting and drying, for modelling purposes.</p><p>(1) Previati et al. (2019), Hydrological Processes.</p>

scholarly journals In Situ CO2 Efflux from Leaf Litter Layer Showed Large Temporal Variation Induced by Rapid Wetting and Drying Cycle

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e108404 ◽  
Author(s):  
Mioko Ataka ◽  
Yuji Kominami ◽  
Kenichi Yoshimura ◽  
Takafumi Miyama ◽  
Mayuko Jomura ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Leaf Litter ◽  
Co2 Efflux ◽  
Litter Layer ◽  
Wetting And Drying ◽  
Wetting And Drying Cycle

scholarly journals Modelling the Quality of Bathing Waters in the Adriatic Sea

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1525
Author(s):  
Christian Ferrarin ◽  
Pierluigi Penna ◽  
Antonella Penna ◽  
Vedrana Spada ◽  
Fabio Ricci ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Management Tool ◽  
Negative Consequences ◽  
Sea Temperature ◽  
Bathing Water Directive ◽  
Bathing Waters ◽  
Diffusion Dynamics ◽  
Study Sites

The aim of this study is to develop a relocatable modelling system able to describe the microbial contamination that affects the quality of coastal bathing waters. Pollution events are mainly triggered by urban sewer outflows during massive rainy events, with relevant negative consequences on the marine environment and tourism and related activities of coastal towns. A finite element hydrodynamic model was applied to five study areas in the Adriatic Sea, which differ for urban, oceanographic and morphological conditions. With the help of transport-diffusion and microbial decay modules, the distribution of Escherichia coli was investigated during significant events. The numerical investigation was supported by detailed in situ observational datasets. The model results were evaluated against water level, sea temperature, salinity and E. coli concentrations acquired in situ, demonstrating the capacity of the modelling suite in simulating the circulation in the coastal areas of the Adriatic Sea, as well as several main transport and diffusion dynamics, such as riverine and polluted waters dispersion. Moreover, the results of the simulations were used to perform a comparative analysis among the different study sites, demonstrating that dilution and mixing, mostly induced by the tidal action, had a stronger effect on bacteria reduction with respect to microbial decay. Stratification and estuarine dynamics also play an important role in governing microbial concentration. The modelling suite can be used as a beach management tool for improving protection of public health, as required by the EU Bathing Water Directive.

scholarly journals Dynamics of the soil respiration response to soil reclamation in a coastal wetland

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiliang Song ◽  
Yihao Zhu ◽  
Weifeng Chen
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Carbon ◽  
Water Content ◽  
Coastal Wetlands ◽  
Positive Relationship ◽  
Soil Reclamation ◽  
Diurnal Changes ◽  
Seasonal Scale ◽  
Study Sites

AbstractThe soil carbon (C) pools in coastal wetlands are known as “blue C” and have been damaged extensively owing to climate change and land reclamation. Because soil respiration (RS) is the primary mechanism through which soil carbon is released into the atmosphere at a global scale, investigating the dynamic characteristics of the soil respiration rate in reclaimed coastal wetlands is necessary to understand its important role in maintaining the global C cycle. In the present study, seasonal and diurnal changes in soil respiration were monitored in one bare wetland (CK) and two reclaimed wetlands (CT, a cotton monoculture pattern, and WM, a wheat–maize continuous cropping pattern) in the Yellow River Delta. At the diurnal scale, the RS at the three study sites displayed single-peak curves, with the lowest values occurring at midnight (00:00 a.m.) and the highest values occurring at midday (12:00 a.m.). At the seasonal scale, the mean diurnal RS of the CK, CT and WM in April was 0.24, 0.26 and 0.79 μmol CO2 m−2 s−1, and it increased to a peak in August for these areas. Bare wetland conversion to croplands significantly elevated the soil organic carbon (SOC) pool. The magnitude of the RS was significantly different at the three sites, and the yearly total amounts of CO2 efflux were 375, 513 and 944 g CO2·m−2 for the CK, CT and WM, respectively. At the three study sites, the surface soil temperature had a significant and positive relationship to the RS at both the diurnal and seasonal scales, and it accounted for 20–52% of the seasonal variation in the daytime RS. The soil water content showed a significant but negative relationship to the RS on diurnal scale only at the CK site, while it significantly increased with the RS on seasonal scale at all study sites. Although the RS showed a noticeable relationship to the combination of soil temperature and water content, the synergic effects of these two environment factors were not much higher than the individual effects. In addition, the correlation analysis showed that the RS was also influenced by the soil physico-chemical properties and that the soil total nitrogen had a closer positive relationship to the RS than the other nutrients, indicating that the soil nitrogen content plays a more important role in promoting carbon loss.

The role of forest deadwood in rockfall protection

2021 ◽  
Author(s):  
Adrian Ringenbach ◽  
Peter Bebi ◽  
Perry Bartelt ◽  
Andrin Caviezel
Keyword(s):  
Basal Area ◽  
Spruce Forest ◽  
Runout Distance ◽  
In Situ Sensors ◽  
Efficient Protection ◽  
Cost Efficient ◽  
Study Sites ◽  
Rockfall Protection

<p>Forests with a high density and basal area of living trees are known for their function as natural and cost-efficient protection against rockfall. The role of deadwood, however, is less understood. We address this knowledge gap in this contribution as we present the results of repeated real-scale experiments in a) a montane beech-spruce forest with and without deadwood and b) in a subalpine scrub mountain pine-spruce forest with deadwood. We used artificial rocks with either an equant or platy shape, masses between 45 kg and 800 kg (≈ 0.3 m3), and equipped with in-situ sensors to gain insights into rotational velocities and impact-accelerations. Clusters of deadwood and erected root plates reduced the mean runout distance at both study sites. For site a), we found that more rocks were stopped behind lying than living trees and that the stopping effect of deadwood was greater for equant compared to platy rock shapes. Site b) revealed a braking effect of scrub mountain pines for relatively small (45 kg), but also a visible reduction in rotational velocities for the 800 kg rocks sensor stream. We conclude that deadwood must be taken into account in rockfall modeling and the management of rockfall protection forests.</p>

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