Name: the calibration and use of capacitance sensors to monitor stem water content in trees
Uploaded: 2017-12-27T15:00:00
Description: Watch this Scientific Journal Video about The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees at JoVE.com

Funding for this study was provided by U.S. Department of Energy&#39;s Office of Science, Office of Biological and Environmental Research, Terrestrial Ecosystem Sciences Program Award No. DE-SC0007041, Ameriflux Management program under Flux Core Site Agreement No. 7096915 through Lawrence Berkeley National Laboratory, and the National Science Foundation Hydrological Science grant 1521238. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the funding agencies.

1. Select a Tree for Instrumentation
<ol>
	<li>Select trees for measurement. Ideally, select trees that are healthy with a generally round stem cross-section, and a diameter between 1-2 times the tine length, or a sapwood depth greater than the length of the sensor tines (~5 cm for the specific capacitance sensors demonstrated here). Measure the depth of the sapwood using tree cores, or for many species, calculate sapwood depth through allometric equations relating sapwood area to stem diameter 29</su...

Seasonal and diurnal patterns in stem water content observed via capacitance sensors align with trends in concurrent sap flux and environmental forcing measurements (Figure 3, Figure 4, Figure 5). Reservoirs of stem water storage are depleted diurnally when the pace of transpiration surpasses the rate of recharge through woody tissues, and seasonally when soil moisture limits root-water availability...

Water stored in plant material plays an integral role in plants&#39; ability to cope with short- and long-term water stress1,2. Plants store water in roots, stems, and leaves in both intracellular and extracellular (e.g., xylem vessels) spaces 2,3,4. This water has been shown to contribute between 10 and 50% of diurnally transpired water2,5,6,7,8. As such, plant hydraulic capacitance is a key component of the terrestrial water balance, can be used as an indicator of water stress, drought response, and recovery1, and is a critical factor necessary to correct for observed time lags between transpiration and sap flow9,10,11. Real-time monitoring of vegetation water content can also be used in agricultural applications to help constrain orchard and crop irrigation in order to increase watering efficiency12,13. However, measurements of continuous, in-situ stem-water content of woody species7,14,15,16,17,18,19 are rare relative to sap flux measurements20. Here, we outline a procedure for the calibration of capacitance sensors to monitor the volumetric water content within the stems of trees5,21.
Hydrodynamic behaviors and water-use regulation by vegetation are an integral component of the soil-plant-atmosphere continuum22,23 and are therefore important controls for the water and carbon fluxes between the biosphere and atmosphere24,25. The dynamics of stem water content are influenced by both biotic and abiotic factors. Depletion and recharge of stem-stored water are affected by short- and long-term trends in environmental conditions, in particular, vapor pressure deficit and soil water content1,26. The physical properties of the wood27 (e.g., density, vessel structure) and the emergent hydraulic strategy25 (e.g., iso- or anisohydric stomatal regulation) determine a plant&#39;s ability to store and use water19,26,28, and can vary widely by species29,30. Previous studies have demonstrated different roles of capacitance in tropical16,27,31,32,33 and temperate5,7,21 species, and in both angiosperms1,2,34 and gymnosperms6,11,17,19.
Improved knowledge of biomass water content will improve understanding of vegetation strategies for water acquisition and use1,2, along with species&#39; vulnerability to predicted changes in precipitation regimes35,36. Further understanding of plant water use strategies will help predict shifting demographic patterns under future climate scenarios37,38. Through model-data fusion techniques39, stem water content data obtained using this methodology can be used to inform and test scalable, plant-level hydrodynamics models40,41,42,43,44 in order to improve calculations of stomatal conductance and, thereby, simulations of both transpiration and photosynthetic carbon uptake. These advanced hydrodynamic models may provide a significant reduction in uncertainty and error when incorporated into larger land-surface and Earth systems models25,45,46,47,48.
Methods used to monitor or calculate stem water content include tree coring33,49, electronic dendrometers2,15,50, electrical resistance51, gamma radiation attenuation52, deuterium tracers19, networks of sap flux sensors32,33,53, stem psychrometers49, and amplitude11 and time4,12,13 domain reflectometry (TDR). Recent efforts have tested the viability of capacitance sensors that have traditionally been used to measure soil volumetric water content5,18,21,27. Frequency domain reflectometry (FRD)-style capacitance sensors are low cost and use relatively small amounts of energy for continuous measurements, making them an attractive tool for high temporal resolution measurements in field scenarios. The ease of automation of FDR over TDR-style sensors facilitates the collection of continuous sun-hourly data sets, and eliminates many of the challenges inherent in TDR measurements requiring substantial cable lengths13. The use of in-situ capacitance sensors eliminates the need for repetitive coring or branch harvesting, and may provide enhanced accuracy for hardwood species. Woody species that withdraw water principally from extracellular spaces, such as xylem vessels, or have high wood or bark moduli of elasticity, are generally not good candidates for popular dendrometer measurement techniques due to low elastic stem expansion2. Capacitance sensors estimate dielectric permittivity, which can be directly converted to volumetric water content. However, capacitance measurements are sensitive to the density of the media surrounding the sensor. Therefore, we advocate for species-specific calibrations that convert the output of the sensors to volumetric wood-water content5,21.
We present a protocol for a species-specific calibration to convert capacitance sensor output to volumetric water content of wood. Also provided are instructions for field installation of capacitance sensors in mature trees and a discussion of the method&#39;s strengths, weaknesses, and assumptions. These techniques are designed to monitor volumetric water content in the trunk, the largest tree water storage reservoir8, but can be easily expanded to the whole tree with installation of additional sensors along the branches. Measurements of dynamic plant water content will advance the fields of vegetation hydrodynamics, biometeorology, and land-surface modeling.

<table>
	<tbody>
		<tr>
			<td>Ruggedized Soil Moisture Sensor</td>
			<td>METER Group Inc.</td>
			<td>GS-3</td>
			<td>Capacitance sensors</td>
		</tr>
		<tr>
			<td>1/8&#34; drill bit</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>9/64&#34; drill bit</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Drying oven</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Chainsaw</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric drill</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Bucket for water bath</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol swabs</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Draw knife</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Data logger</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon sealant</td>
			<td>Any</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

the calibration and use of capacitance sensors to monitor stem water content in trees

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus area. Biomass capacitance plays an integral role in the avoidance of hydraulic impairment to transpiration. However, high temporal resolution measurements of dynamic changes in the hydraulic capacitance of large trees are rare. Here, we present procedures for the calibration and use of capacitance sensors, typically used to monitor soil water content, to measure the volumetric water content in trees in the field. Frequency domain reflectometry-style observations are sensitive to the density of the media being studied. Therefore, it is necessary to perform species-specific calibrations to convert from the sensor-reported values of dielectric permittivity to volumetric water content. Calibration is performed on a harvested branch or stem cut into segments that are dried or re-hydrated to produce a full range of water contents used to generate a best-fit regression with sensor observations. Sensors are inserted into calibration segments or installed in trees after pre-drilling holes to a tolerance fit using a fabricated template to ensure proper drill alignment. Special care is taken to ensure that sensor tines make good contact with the surrounding media, while allowing them to be inserted without excessive force. Volumetric water content dynamics observed via the presented methodology align with sap flow measurements recorded using thermal dissipation techniques and environmental forcing data. Biomass water content data can be used to observe the onset of water stress, drought response and recovery, and has the potential to be applied to the calibration and evaluation of new plant-level hydrodynamics models, as well as to the partitioning of remotely sensed moisture products into above- and belowground components.

In this section, we present calibration data for five common eastern forest tree species, followed by a detailed analysis of field measurements of stem-water storage in three Acer rubrum individuals during the 2016 growing season. Calibration curves were generated for Acer rubrum, Betula papyrifera, Pinus strobus, Populus grandidentata, and Quercus rubra (Figure 1). Slopes of the curves differed by as much as 97.7% for P. grandi...

Watch this Scientific Journal Video about The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees at JoVE.com

The Calibration and Use of Capacitance Sensors to Monitor Stem Water Content in Trees

The hydraulic capacitance of biomass is a key component of the vegetation water budget, which serves as a buffer against short and long-term drought stresses. Here, we present a protocol for the calibration and use of soil moisture capacitance sensors to monitor water content in the stems of large trees.

Water transport and storage through the soil-plant-atmosphere continuum is critical to the terrestrial water cycle, and has become a major research focus ...

The overall goal of this methodology is to continuously monitor the volumetric water content in the stems of mature living trees. This method can help answer key questions in the field of ecohydrology, such as how vegetation responds to moisture limitation, including when water stress begins and how quickly drought recovery occurs. The main advantage of this technique is that it allows for automated measurements of biomass water content and C2 at subhourly timesteps.The implications of this technique extend toward remote sensing because measurements of above-ground water content are necessary for the partitioning of remotely-sensed data products and to above-and below-ground components. Though this method can provide insight into drought response it can also be extended to other phenomena, such as monitoring fuel water content for forest fire ignition prediction. This is my undergraduate Rio Mursinna, who will help us with selecting a branch and harvesting branch segments.This is Kelly Malone, an undergraduate research assistant in my lab. After selecting a tree for instrumentation as described in the text protocol, proceed with collecting about four meters or more of wood from the trunk or a branch that is at least six centimeters in diameter. Larger diameters are better.Next remove any attached branches, leaves, lichen, or any other loose material. Then slice the sample into cylindrical sections that are about 15 centimeters long. Make at least 25 such sections.Then label each segment and record each segment's average diameter and length. Also record each segment's volume, assuming a cylindrical shape. Set aside a segment from the center and from the end for the baseline analysis.Then place one-third of the remaining segments in a water bath to rehydrate, and put the other two-thirds in a drying oven set to 60 degrees Celsius to dry. To begin, connect a capacitance sensor to a data-logging device and to a computer for real-time sensor readout visualization. Set it to collect data on 30-second intervals.Begin with analyzing the segments saved for the baseline analysis. Begin with drilling two new sets of holes for the sensor in each segment. Make the hole diameter slightly smaller than the tines.Place the hole sets about two centimeters apart vertically and 150 degrees apart radially. Next, weigh the segments to the nearest hundredth of a gram. Then seal the ends of the segments with plastic wrap so they do not dry out.Now clean the tines of the capacitance sensor with alcohol and insert them into one set of drilled holes such that the tines are completely buried in the wood. Next, wait a few minutes for readings to stabilize. Then collect 10 measurements over five minutes.Use the average value for future analyses. Now, gently remove the sensor and clean the tines with alcohol. When the output readings return to zero, take 10 measurements from the second set of holes.After taking measurements, remove the plastic and place the segments in the oven. During the first two days of drying, there is a lot of moisture loss, so take measurements twice a day. Later, take measurements just once per day.During each measurement session, only drill and analyze one or two segments. For the rehydrating segments, measure them once daily until each has been measured. Always dry them off before taking measurements.Once these segments have been fully rehydrated, transfer them to the oven to desiccate. To begin, select a location for the sensor installation on the tree of interest and record the stem diameter at that location. The standard pairing of sensor locations it to place one about a half meter above the ground into the trunk, and place the second just below the first major branching split.At the selected locations, use a draw blade to remove the bar to expose the cambium to create a flat surface where the sensor will be installed. The sensor must sit flush against the surface with no parts of the tines exposed, and the measurements must only come from the water content in the xylem, excluding the water content of the bark or phloem. Drilling appropriately-sized holes at the correct alignment and the correct depth is essential for the functionality of this method.If the sensor meets with too much resistance, carefully back the sensor out and widen the holes. Next drill the holes for the tines. In soft wood, use a drill bit slightly smaller than the diameter of the tines, whereas in hard wood, use a bit closer to the true size of the tines.Prior to installing a sensor, clean it with alcohol. When attempting to insert it, if there is too much resistance, use the drill to widen the holes slightly. Ultimately, all three tines should be fully inserted with the body of the sensor flush against the tree trunk.Use a silicone-based sealant to seal the sensor to the tree and prevent infestation. Then cover the sensor with reflective insulation to avoid external heating, and connect all of the sensors to a power source and to a compatible data logger. Using the laboratory-based technique with stem segments, calibrations were performed for five common Eastern forest tree species, representing a variety of wood densities and xylem structures.Calibration curves different by as much as 97.7%for populus grandidentata and acer rubrum, demonstrating to the need to perform species-specific calibration to obtain accurate VWC measurements. To evaluate the observed diurnal dynamics, the rate of change in total water content was compared to sap flux data, collected simultaneously in the same tree using Granier-style thermal dissipation sensors. Next, three acer rubrum trees were studied in the field.While total stem water storage is dependent on the volume of the trunk, all three individuals exhibited patterns of recharge and replenishment, consistent with seasonal trends and sap flux and available moisture in the top meter of soil. Stem-stored water, sap flux, and soil moisture were all at their lowest during the end-of-summer extended interstorm period. From this data, the drought recovery time for acer rubrum is estimated at 10 days.After watching this video, you should have a good understanding of how to calibrate, install, and operate a capacitance sensor to monitor water content in a living biomass. Following this procedure, additional sensors could be added along the branching structure to perform a whole-tree water balance. After its development, this technique paved the way for researchers in ecohydrology and land-surface modeling to evaluate model performance on the basis of ecosystem water storage and energy flux.

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Environment

A Venturi Effect Can Help Cure Our Trees

In woody plants, xylem sap moves upwards through the vessels due to a decreasing gradient of water potential from the groundwater to the foliage. According to these factors and their dynamics, small amounts of sap-compatible liquids (i.e. pesticides) can be injected into the xylem system, reaching their target from inside. This endotherapic method, called &#34;trunk injection&#34; or &#34;trunk infusion&#34; (depending on whether the user supplies an external pressure or not), confines the applied chemicals only within the target tree, thereby making it particularly useful in urban situations. The main factors limiting wider use of the traditional drilling methods are related to negative side effects of the holes that must be drilled around the trunk circumference in order to gain access to the xylem vessels beneath the bark.
The University of Padova (Italy) recently developed a manual, drill-free instrument with a small, perforated blade that enters the trunk by separating the woody fibers with minimal friction. Furthermore, the lenticular shaped blade reduces the vessels&#39; cross section, increasing sap velocity and allowing the natural uptake of an external liquid up to the leaves, when transpiration rate is substantial. Ports partially close soon after the removal of the blade due to the natural elasticity and turgidity of the plant tissues, and the cambial activity completes the healing process in few weeks.

Compared to the more traditional hole-based methods, most of which require the tree to be drilled, tools with lenticular blades transform the basics of endotherapy easing the closure of the wound and allowing the natural uptake of the solutions.

In woody plants, xylem sap moves upwards through the vessels due to a decreasing gradient of water potential from the groundwater to the foliage. ...

Unraveling the Unseen Players in the Ocean - A Field Guide to Water Chemistry and Marine Microbiology

Here we introduce a series of thoroughly tested and well standardized research protocols adapted for use in remote marine environments. The sampling protocols include the assessment of resources available to the microbial community (dissolved organic carbon, particulate organic matter, inorganic nutrients), and a comprehensive description of the viral and bacterial communities (via direct viral and microbial counts, enumeration of autofluorescent microbes, and construction of viral and microbial metagenomes). We use a combination of methods, which represent a dispersed field of scientific disciplines comprising already established protocols and some of the most recent techniques developed. Especially metagenomic sequencing techniques used for viral and bacterial community characterization, have been established only in recent years, and are thus still subjected to constant improvement. This has led to a variety of sampling and sample processing procedures currently in use. The set of methods presented here provides an up to date approach to collect and process environmental samples. Parameters addressed with these protocols yield the minimum on information essential to characterize and understand the underlying mechanisms of viral and microbial community dynamics. It gives easy to follow guidelines to conduct comprehensive surveys and discusses critical steps and potential caveats pertinent to each technique.

Here, we present a comprehensive protocol to assess the organic and inorganic nutrient availability and the abundance and structure of microbial and viral communities in remote marine environments.

Here we introduce a series of thoroughly tested and well standardized research protocols adapted for use in remote marine environments. The sampling ...

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water&#8217;s surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males.

Use of Chironomidae Diptera Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

Rapid bioassessment protocols using benthic macroinvertebrates are often used to monitor and assess water quality. An efficient protocol involves collections of Chironomidae surface-floating pupal exuviae (SFPE). Here, techniques for field collection, laboratory processing, slide mounting, and identification of Chironomidae SFPE are described.

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. ...

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH4 vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF6)&#160;tracer gas method is commonly used to measure enteric CH4 production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH4 and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal&#8217;s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH4 and CO2 concentrations. Field comparisons of AHCS to respiration chambers or SF6 have demonstrated that AHCS produces repeatable and accurate CH4 emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO2 and CH4 fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

Use of a Filter Cartridge for Filtration of Water Samples and Extraction of Environmental DNA

Recent studies demonstrated the use of environmental DNA (eDNA) from fishes to be appropriate as a non-invasive monitoring tool. Most of these studies employed disk fiber filters to collect eDNA from water samples, although a number of microbial studies in aquatic environments have employed filter cartridges, because the cartridge has the advantage of accommodating large water volumes and of overall ease of use. Here we provide a protocol for filtration of water samples using the filter cartridge and extraction of eDNA from the filter without having to cut open the housing. The main portions of this protocol consists of 1) filtration of water samples (water volumes &#8804;4 L or &gt;4 L); (2) extraction of DNA on the filter using a roller shaker placed in a preheated incubator; and (3) purification of DNA using a commercial kit. With the use of this and previously-used protocols, we perform metabarcoding analysis of eDNA taken from a huge aquarium tank (7,500 m3) with known species composition, and show the number of detected species per library from the two protocols as the representative results. This protocol has been developed for metabarcoding eDNA from fishes, but is also applicable to eDNA from other organisms.

We describe a protocol for filtration of water samples with a filter cartridge and extraction of environmental DNA (eDNA) without having to cut open the housing to remove the filter. This protocol is developed for metabarcoding eDNA from fishes, but is also applicable to eDNA from other organisms.

Recent studies demonstrated the use of environmental DNA (eDNA) from fishes to be appropriate as a non-invasive monitoring tool. Most of these studies ...

Methods of Soil Resampling to Monitor Changes in the Chemical Concentrations of Forest Soils

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scientific community. The objective of this protocol is therefore to synthesize the latest information on methods of soil resampling in a format that can be used to design and implement a soil monitoring program. Successful monitoring of forest soils requires that a study unit be defined within an area of forested land that can be characterized with replicate sampling locations. A resampling interval of 5 years is recommended, but if monitoring is done to evaluate a specific environmental driver, the rate of change expected in that driver should be taken into consideration. Here, we show that the sampling of the profile can be done by horizon where boundaries can be clearly identified and horizons are sufficiently thick to remove soil without contamination from horizons above or below. Otherwise, sampling can be done by depth interval. Archiving of sample for future reanalysis is a key step in avoiding analytical bias and providing the opportunity for additional analyses as new questions arise.

Repeated soil sampling has recently been shown to be an effective way to monitor forest soil change over years and decades. To support its use, a protocol is presented that synthesizes the latest information on soil resampling methods to aid in the design and implementation of successful soil monitoring programs.

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental ...

Controlled-release of Chlorine Dioxide in a Perforated Packaging System to Extend the Storage Life and Improve the Safety of Grape Tomatoes

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties of the pouch were monitored in containers with or without fruit. The pouch was affixed to the inside of a perforated clamshell containing grape tomatoes, and the effect on microbial population, firmness, and weight loss was evaluated during a 14 day storage period at 20 &#176;C. Within 3 days, the ClO2 concentration in the clamshells reached 3.5 ppm and remained constant until day 10. Thereafter, it decreased to 2 ppm by day 14. The ClO2 pouch exhibited strong antimicrobial activity, reducing Escherichia coli populations by 3.08 log CFU/g and Alternaria alternata populations by 2.85 log CFU/g after 14 days of storage. The ClO2 treatment also reduced softening and weight loss and extended the overall shelf life of the tomatoes. Our results suggest that ClO2 treatment is useful for extending the shelf life and improving the microbial safety of tomatoes during storage without impairing their quality.

Here, we describe a protocol for the application of a novel, slow-release ClO2 product that reduces spoilage and extends the shelf life of fresh fruit. The slow-release ClO2 product was added to standard commercial grape tomato packaging and tested against Escherichia coli and Alternaria alternata.

A controlled-release chlorine dioxide (ClO2) pouch was developed by sealing a slurry form of ClO2 into semipermeable polymer film; the release properties ...

A Simple Planting Technique for Re-establishing Trees Where Frequent Inundation Occurs

Many of the Everglades tree islands have lost elevation over the past century and most of their trees have died such that they are now covered with herbaceous plants. This protocol describes a simple, cost-effective tree planting technique needed for restoring degraded Everglade tree islands. The design is patterned after a natural Everglades process that creates floating peat islands, which allows tree survival and growth in flooded conditions and often leads to the development of tree islands. Commercially available peat bags were used as the medium for the growth and establishment of potted native tree saplings. The pop-up configuration floated initially and provided additional elevation to minimize inundation, with a single native tree species sapling and a single tree fertilizer spike. During a 3 year study involving 105 pop-ups, most plants survived (80%) and many thrived. Determining whether this technique can establish trees on a degraded tree island will require longer studies and extensive field tests.

This protocol describes a simple, cost-effective tree planting technique for restoring degraded Everglades tree islands that experience inundation. The design creates an island (pop-up) which floats initially and adds elevation to promote tree survival and growth under flooded conditions.

Many of the Everglades tree islands have lost elevation over the past century and most of their trees have died such that they are now covered with ...

Construction of a Low-cost Mobile Incubator for Field and Laboratory Use

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water quality. However, commercially available incubators are often costly, difficult to transport, not flexible in terms of volume, and/or poorly adapted to local field conditions where access to electricity is unreliable. The purpose of this study was to develop an adaptable, low-cost and transportable incubator that can be constructed using readily available components. The electronic core of the incubator was first developed. These components were then tested under a range of ambient temperature conditions (3.5 &#176;C - 39 &#176;C) using three types of incubator shells (polystyrene foam box, hard cooler box, and cardboard box covered with a survival blanket). The electronic core showed comparable performance to a standard laboratory incubator in terms of the time required to reach the set temperature, inner temperature stability and spatial dispersion, power consumption, and microbial growth. The incubator set-ups were also effective at moderate and low ambient temperatures (between 3.5 &#176;C and 27 &#176;C), and at high temperatures (39 &#176;C) when the incubator set temperature was higher. This incubator prototype is low-cost (&lt; 300 USD) and adaptable to a variety of materials and volumes. Its demountable structure makes it easy to transport. It can be used in both established laboratories with grid power or in remote settings powered by solar energy or a car battery. It is particularly useful as an equipment option for field laboratories in areas with limited access to resources for water quality monitoring.

This paper describes a method for building an adaptable, low-cost and transportable incubator for microbial testing of drinking water. Our design is based on widely available materials and can operate under a range of field conditions, while still offering the advantages of higher-end laboratory-based models.

Incubators are essential for a range of culture-based microbial methods, such as membrane filtration followed by cultivation for assessing drinking water ...

BtM, a Low-cost Open-source Datalogger to Estimate the Water Content of Nonvascular Cryptogams

Communities of nonvascular cryptogams, such as mosses or lichens, are an important part of the Earth's biodiversity, contributing to the regulation of the carbon and nitrogen cycles in many ecosystems. Being poikilohydric organisms, they do not actively control their internal water content and need a humid environment to activate their metabolism. Therefore, studying water relationships of nonvascular cryptogams is crucial to understand both their diversity patterns and their functions in the ecosystems. We present the BtM datalogger, a low-cost open-source platform for the study of the water content of nonvascular cryptogams. The datalogger is designed to measure ambient temperature, humidity, and conductance from up to eight samples simultaneously. We provide a design for a printed circuit board (PCB), a detailed protocol to assemble the components, and the required source code. All this makes the assembly of the BtM datalogger accessible to any research group, even to those without previous specialized knowledge. Therefore, the design presented here has the potential to help popularize the use of this type of device among ecologists and field biologists.

We present a simple and cost-effective method to build an open-source datalogger that measures the conductance of nonvascular cryptogams together with the environmental temperature and humidity. We describe the hardware design of the datalogger and provide step-by-step assembly instructions, the list of required open-source logging software, the code to run the datalogger, and a calibration protocol.

Communities of nonvascular cryptogams, such as mosses or lichens, are an important part of the Earth's biodiversity, contributing to the regulation of the ...