Name: capturing flow-weighted water and suspended particulates from agricultural canals during drainage events
Uploaded: 2017-11-07T14:00:00
Description: Watch this Scientific Journal Video about Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events at JoVE.com

We wish to thank Pablo Vital and Johnny Mosley for help with field sampling, and Viviana Nadal and Irina Ognevich for help with laboratory analyses.

1. Datalogger Installation and Workings
<ol>
	<li>Identify a study farm and install a datalogger that triggers an autosampler to collect composite flow samples on a flow proportional basis, which requires monitoring canal levels, pump head revolutions, and pump calibration equation.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56088/56088fig1.jpg" /> 
Figure 1: ISCO sampler used to program auto-sampling proce...

<ol>
	<li>Sims, J. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorus+loss+in+agricultural+drainage:+historical+perspective+and+current+research.">Phosphorus loss in agricultural drainage: historical perspective and current research.</a> J. Environ. Qual. 27, 277-293 (1997).</li><li>Van Esbroeck, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+and+subsurface+phosphorus+export+from+agricultural+fields+during+peak+flow+events+over+the+non-growing+season+in+regions+with+cool,+temperate+climates.">Surface and subsurface phosphorus export from agricultural fields during peak flow events over the non-growing season in regions with cool, temperate climates.</a> J. Soil Water Conserv. 72, 65-76 (2017).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorus+mass+balance+and+internal+load+in+an+impacted+subtropical+isolated+wetland.">Phosphorus mass balance and internal load in an impacted subtropical isolated wetland.</a> Water Air Soil Pollut. 218, 619-632 (2011).</li><li>Eyre, B. D., McConchie, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+implications+of+sedimentological+studies+for+environmental+pollution+assessment+and+management:+Examples+from+fluvial+system+in+north+Queensland+and+western+Australia.">The implications of sedimentological studies for environmental pollution assessment and management: Examples from fluvial system in north Queensland and western Australia.</a> Sediment. Geol. 85, 235-252 (1993).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soil+phosphorus+release+and+storage+capacity+from+an+impacted+subtropical+wetland.">Soil phosphorus release and storage capacity from an impacted subtropical wetland.</a> Soil Sci. Soc. Amer. J. , 74 (2010).</li><li>Kenney, W. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-basin,+mass-balance+approach+for+identifying+critical+phosphorus-loading+thresholds+in+shallow+lakes.">Whole-basin, mass-balance approach for identifying critical phosphorus-loading thresholds in shallow lakes.</a> Journal of Paleolim. 51, 515-528 (2014).</li><li>Freebairn, D. N., Wockner, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+soil+erosion+on+vertisols+of+the+Eastern+Darling+Downs,+Queensland.+Effects+of+surface+conditions+on+soil+movement+within+contour+bay+catchments.">A study of soil erosion on vertisols of the Eastern Darling Downs, Queensland. Effects of surface conditions on soil movement within contour bay catchments.</a> Aust. J.Soil Res. 24, 135-158 (1986).</li><li>Erickson, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Optimizing stormwater treatment practices: a handbook of assessment and maintenance. , (2013).</li><li>Abtew, W., Obeysekera, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drainage+Generation+and+Water+Use+in+the+Everglades+Agricultural+Area+Basin.">Drainage Generation and Water Use in the Everglades Agricultural Area Basin.</a> J. Amer. Water Res. Asso. 32, 1147-1158 (1996).</li><li>Daroub, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+management+practices+and+long-term+water+quality+trends+in+the+Everglades+Agricultural+Area.">Best management practices and long-term water quality trends in the Everglades Agricultural Area.</a> Cri. Rev. Environ. Sci. Technol. 41, 608-632 (2011).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+suspended+particulates+on+phosphorus+loading+exported+from+farm+drainage+during+a+storm+event+in+the+Everglades+Agricultural+Area.">Influence of suspended particulates on phosphorus loading exported from farm drainage during a storm event in the Everglades Agricultural Area.</a> J. Soil Sed. 17, 240-252 (2017).</li><li>Diaz, O. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sediment+inventory+and+phosphorus+fractions+for+water+conservation+area+canals+in+the+Everglades.">Sediment inventory and phosphorus fractions for water conservation area canals in the Everglades.</a> Soil Sci. Soc. Amer. J. 70, 863-871 (2006).</li><li>Reddy, K. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forms+of+soil+phosphorus+in+selected+hydrologic+units+of+Florida+Everglades.">Forms of soil phosphorus in selected hydrologic units of Florida Everglades.</a> Soil Sci. Soc. Amer. J. 62, 1134-1147 (1998).</li><li>Hedley, M. J., Stewart, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+to+measure+microbial+phosphate+in+soils.">Method to measure microbial phosphate in soils.</a> Soil Biol. Biochem. 14, 377-385 (1982).</li><li>O'Dell, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Method 365.1, Revision 2.0: Determination of Phosphorus by Semi-Automated Colorimetry. , (1993).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+aquatic+vegetation+on+phosphorus+loads+in+the+Everglades+Agricultural+Area.">Effect of aquatic vegetation on phosphorus loads in the Everglades Agricultural Area.</a> J. Aqu. Pla. Man. 53, 44-53 (2015).</li></ol>

The autosamplers for drainage water particulate collection were placed near the exiting pump station dataloggers. Power was supplied by 12 V batteries that are charged by solar panels. The autosamplers were controlled by the on-site dataloggers, which turned the autosamplers on when the exit pumps ran, and turned them off when pumping stopped. Openings of the sampler intake lines were positioned 0.5 m above the canal bottom and upflow from the pump station. The intake lines were held in place by installing a metal rebar ...

The fate and transport of suspended particulates has been the subject of numerous studies due to its role in eutrophication, particularly in agricultural systems1,2. A comprehensive evaluation of nutrients contained in particulate matter within an aquatic system is necessary to investigate numerous environmental issues such as, the internal cycling of nutrients and release to the overlying water column3, substrate stability, light availability within the water column, and eventually water quality concerns to downstream ecosystems4. The quantity of phosphorus (P) stored in the particulate form (organic matter or sediments) is typically greater than in the water column5. A study conducted by Kenney et al.6 showed that recent sediments that were deposited in Lake Lochloosa, Florida were between the age range of 1900 and 2006. These younger sediments contained nearly 55 times more P than that which was present in the water column. One approach to characterize the potential impact that particulates may have on a particular system is to conduct a quantitative inventory of phosphorus stored in sediment discharged during drainage events. Collection and analysis of these discharged particulates can help estimate downstream nutrient enrichment impacts on sensitive ecosystems.
Storm events typically represent a small fraction of time, yet may contribute the majority of P load discharge in farm drainage. This is because in order to prevent fields from flooding, a large volume of water is drained over short periods of time. Rainfall intensity and flow rates are vital driving factors that can control the concentration of suspended sediments in overland runoff7. Designing monitoring methods that captures flow-weighted composite water samples would help avoid errors associated with complex, high intensity rain events. During high discharge events like storms, the quick and drastic changes in concentrations may not be representative of the average pollutant concentration for the incremental volume. Therefore, flow-weighted water samples far more accurately represents the concentration of a discharge event as it is a summation of loads over a period of time8. The most common flow-weighted samples are automatically collected discrete or composite samples. By capturing the exported suspended particulates from farm drainage during discharge allows us to quantify the severity of the event on P loading. The method described in this study helps capture the particulates that can later be characterized for various physical and chemical properties. The novelty of sampling drainage discharge using a continuous composite flow method versus grab sampling is that it is a better representation of field conditions over the entire duration of the drainage event. Whereas, grab sampling is a &#8220;snapshot&#8221; in time and may not fully represent the effect of the entire event.
The Everglades Agricultural Area (EAA) in South Florida, USA is a large expanse of the original Everglades that was channelized and drained for farming, commercial, and residential development. Nearly 1,100 million m3 of water is discharged annually from and through the EAA to the south and southeast9. Soils in the EAA are Histosols that commonly contain over 85% organic matter by weight and have less than 35% mineral content10. Canal sediments typically have low bulk density (between 0.14 g cm-3 to 0.35 g cm-3), high organic matter content (between 31 - 35%) and Total P (TP) values ranging between 726 -1,089 mg kg-1 11.
For the purpose of this demonstration, a farm within the EAA was selected. The hydroscape of how water flows within the EAA depends on pumps and gravity. Each farm in the EAA comprises on at least one main canal, and multiple field ditches. The field ditches run perpendicular to the main canal. The pumps typically serve a dual purpose; they deliver irrigation water to the farm, and also discharge drainage water off-site. When the fields need to be drained, water in the main canal is lowered, and water from the field drains into the ditches, driven by a hydraulic gradient. Due to only a slight slope in surface most of the rainfall that occurs on the fields flows through the soil profile in transit to the field ditches.&#160; During irrigation, the system is reversed. There is no network of tile drainage in the EAA. The water table is maintained at a specific height due to a confining layer of limestone bedrock underling the soils.&#160; Water is brought in through the main canals; field ditches are filled, and water is allowed to seep into the soil profile to raise the water table levels in the fields. Typically, demands for irrigation water in the EAA occur during March, April, and May (dry season), with very little drainage discharge. In contrast, the volume of water being discharged between June and October (wet season) is significantly higher. The presence of canal bank berms and ditches allows for minimal surface runoff as a potential source of P loading into farm canals12.
In this visual experiment, we present a novel method of capturing flow-weighted suspended particulates during drainage events that can later be used for physico-chemical characterization such as bulk density, organic matter content, and P fractionation13,14.

<table width="602">
	<tbody>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Datalogger</td>
			<td style="width:83px;">Campbell Scientific</td>
			<td style="width:137px;"></td>
			<td style="width:167px;">model CR1000</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Auto-sampler</td>
			<td style="width:83px;">ISCO</td>
			<td style="width:137px;"></td>
			<td>model 3700</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Pressure transducer</td>
			<td style="width:83px;">KPSI</td>
			<td style="width:137px;"></td>
			<td>model 700</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Tipping bucket rain guage</td>
			<td style="width:83px;">Texas Electronics</td>
			<td style="width:137px;"></td>
			<td>model TR-525</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Potassium Chloride</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7447-40-7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Sodium Hydroxide</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">1310-73-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Hydrochloric Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7647-01-0</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Sulfuric Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7664-93-9</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Potassium Persulfate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7727-21-1</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Ammonium Molybdate Tetrahydrate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">12054-85-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">L-Ascorbic Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">50-81-7</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">100 mg/L Anhydrous Phosphate Standard</td>
			<td style="width:83px;">ERA</td>
			<td style="width:137px;">061</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Antimony Potassium Tartrate Trihydrate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">28300-74-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Durapore Membrane Filters</td>
			<td style="width:83px;">Millipore</td>
			<td style="width:137px;">HVLP04700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Whatman #41 Filter Paper</td>
			<td style="width:83px;">Whatman</td>
			<td style="width:137px;">1441-150</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fixed Speed Reciprocal Shaker E6010</td>
			<td style="width:83px;">Eberbach Corporation</td>
			<td style="width:137px;">E6010.00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Disposable Culture Tubes</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">14-961-29</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Allegra 25R Centrifuge</td>
			<td style="width:83px;">Becker Coulter</td>
			<td style="width:137px;">U.S. 605168-AC</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Parafilm</td>
			<td style="width:83px;">Bemis Company Inc PM 999</td>
			<td style="width:137px;">13-374-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Oak Ridge Centrifuge Tubes</td>
			<td style="width:83px;">Nalgene</td>
			<td style="width:137px;">3119-0050</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fisherbrand 20mL HDPE Scintillation Vials with Urea Cap</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">03-337-23C</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fisherbrand&#160;Natural Polypropylene Jars with White Polypropylene Unlined Cap</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">02-912-024A</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">0.45 membrane filters</td>
			<td style="width:83px;">Cole-Parmer</td>
			<td>Item # UX-15945-25</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">100 ml digestion tubes</td>
			<td style="width:83px;">Fisher&#160;</td>
			<td>TC1000-0735</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Glass funnels</td>
			<td style="width:83px;">Fisher</td>
			<td>03-865</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Spectronic 20 Genesys</td>
			<td style="width:83px;">Thermo-Fisher</td>
			<td>4001-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">QuikChem</td>
			<td style="width:83px;">Latchat</td>
			<td style="width:137px;">8500</td>
			<td></td>
		</tr>
	</tbody>
</table>

capturing flow-weighted water and suspended particulates from agricultural canals during drainage events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

The method described in this study allows us to capture water and particulate matter that is being discharged during pumping events in farms canals. The water and particulates that are collected are flow-weighted, which means that they are representative of the entire duration of the pumping event and not just a onetime snapshot; making it highly representative of the type of material being discharged. The water and suspended particulates can be stored to be analyzed for various physical ...

Watch this Scientific Journal Video about Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events at JoVE.com

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

The overall goal of this procedure is to provide a novel method for capturing in situ composite flow-weighted farm canal discharge water and suspended particulates during drainage events for their physical chemical characterization. This method will help address the most fundamental step in the field of environmental hydrology, which is collecting a water sample that fully represents a flow event in its entirety. The main advantages of this technique are that it is automated and that it provides a composite sample that is highly representative of typical discharge material present during flow events.This method can provide insight into water quality parameters during routine drainage events as well as during storm events when large volumes of water are discharged over multiple days. Designing monitoring methods that capture flow-weighted composite water samples could help avoid errors associated with complex, high-intensity rain events. Demonstrating the procedure will be research associate, Doctor Timothy Lang, along with field technicians, Pablo and Johnny.After identifying a study farm, install a datalogger near the pump station that triggers an auto-sampler to collect composite flow samples on a flow proportional basis. Use the pressure transducers installed in the inflow and outflow canals, adjacent to the pump station, to monitor the farm canal levels and use the proximity switches installed on the pump heads to monitor the pump speed. To calculate the drainage, use a datalogger and a pump calibration equation for each pump.To program the in situ automated sampler located at the pump station to capture daily composite water samples, first press Enter Program. Then press Program, Flow-based Sampling, Sample every one pulses, 30 composite samples and Sample Volume of 130 milliliters. Press Enter for calibrate sample volume and for Enter Start Time.Then press Program Sequence Complete. Then store the flow-weighted composite samples in an onsite refrigerator at four degrees Celsius until their analysis. To capture suspended particulates, position two, 200 liter PVC settling tanks a few feet from the datalogger to collect farm canal discharge water over the duration of the drainage period.To program the datalogger to collect the particulate samples, press Program, Time-Based Sampling and Sample every two minutes. For composite samples, select 200 and select No for calibrate sample volume and enter start time. Then press Sequence Complete and push Sampling button.Two liters of flow-weighted drainage water will be collected in the settling tanks, every two minutes. As the particulates begin to settle in the tanks, use a hose to siphon off the excess water and transfer the particulates into five-gallon buckets for transport back to the lab for 24-hour equilibration at four degrees Celsius. When the particulates have settled, siphon off the excess water and transfer the particulates into Imhoff settling cones.After one hour, siphon off the excess water one last time and transfer the settled particulates into pre-weighed 500 milliliter screw top jars. Be sure to collect the water below the surface and away from the sides of the cone to reduce the number of aspirated particulates. In this representative experiment, suspended particulates from three farm canals within the Everglade Agricultural Area were collected as demonstrated, and determined to be highly organic, to possess a low bulk density and to be rich nutrients like phosphorous, properties that are highly representative of the water and sediments typically found for the Everglades Agricultural Area soil types and surrounding land use practices.While attempting this procedure, it's important to remember to allow the particulates to fully settle before removing excess water. Following this procedure, other methods like phosphorous fractionation using the Hedley et al. method, can be used to evaluate how much labile versus recalcitrant phosphorous is present in the particulates.After watching this video, you should have a good understanding of how to collect a composite flow-weighted discharge water as opposed to grab sampling. By having a refrigerator onsite, it is possible to preserve the water samples at four degrees Celsius. An added advantage of using this method for collecting water samples is that it is automated and it can be used to capture discharge events associated with storms and hurricanes that can last up to a few days.

capturing-flow-weighted-water-suspended-particulates-from

Research

JoVE Journal

Environment

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This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of ...

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) loading from lake sediments can account for a substantial portion of the total P load in eutrophic, and some mesotrophic, lakes. Laboratory determination of P release rates from sediment cores is one approach for determining the role of internal P loading and guiding management decisions. Two principal alternatives to experimental determination of sediment P release exist for estimating internal load: in situ measurements of changes in hypolimnetic P over time and P mass balance. The experimental approach using laboratory-based sediment incubations to quantify internal P load is a direct method, making it a valuable tool for lake management and restoration.
Laboratory incubations of sediment cores can help determine the relative importance of internal vs. external P loads, as well as be used to answer a variety of lake management and research questions. We illustrate the use of sediment core incubations to assess the effectiveness of an aluminum sulfate (alum) treatment for reducing sediment P release. Other research questions that can be investigated using this approach include the effects of sediment resuspension and bioturbation on P release.
The approach also has limitations. Assumptions must be made with respect to: extrapolating results from sediment cores to the entire lake; deciding over what time periods to measure nutrient release; and addressing possible core tube artifacts. A comprehensive dissolved oxygen monitoring strategy to assess temporal and spatial redox status in the lake provides greater confidence in annual P loads estimated from sediment core incubations.

Lake eutrophication is a water quality issue worldwide, making the need to identify and control nutrient sources critical. Laboratory determination of phosphorus release rates from sediment cores is a valuable approach for determining the role of internal phosphorus loading and guiding management decisions.

Eutrophication is a water quality issue in lakes worldwide, and there is a critical need to identify and control nutrient sources. Internal phosphorus (P) ...

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) &#62; 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW &#60; 0.70).

A protocol about the characterization and application of five different passive sampling devices is presented.

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study ...

Extraction of Organochlorine Pesticides from Plastic Pellets and Plastic Type Analysis

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment during manufacturing and transport. Because of their environmental persistence, they are widely distributed in the oceans and on beaches all over the world. They can act as a vector of potentially toxic organic compounds (e.g., polychlorinated biphenyls) and might consequently negatively affect marine organisms. Their possible impacts along the food chain are not yet well understood. In order to assess the hazards associated with the occurrence of plastic pellets in the marine environment, it is necessary to develop methodologies that allow for rapid determination of associated organic contaminant levels. The present protocol describes the different steps required for sampling resin pellets, analyzing adsorbed organochlorine pesticides (OCPs) and identifying the plastic type. The focus is on the extraction of OCPs from plastic pellets by means of a pressurized fluid extractor (PFE) and on the polymer chemical analysis applying Fourier Transform-InfraRed (FT-IR) spectroscopy. The developed methodology focuses on 11 OCPs and related compounds, including dichlorodiphenyltrichloroethane (DDT) and its two main metabolites, lindane and two production isomers, as well as the two biologically active isomers of technical endosulfan. This protocol constitutes a simple and rapid alternative to existing methodology for evaluating the concentration of organic contaminants adsorbed on plastic pieces.

Microplastics act as vector of potentially toxic organic contaminants with unpredictable effects. This protocol describes an alternative methodology for assessing the levels of organochlorine pesticides adsorbed on plastic pellets and identifying the polymer chemical structure. The focus is on pressurized fluid extraction and attenuated total reflectance Fourier transform infrared spectroscopy.

Plastic resin pellets, categorized as microplastics (&#8804;5 mm in diameter), are small granules that can be unintentionally released to the environment ...

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in water resources is a prerequisite for understanding the drivers of the pollutant loads and for making informed water resource management decisions. The commonly used &#34;grab sampling&#34; method provides the concentrations of pollutants at the time of sampling (i.e., a snapshot concentration) and may under- or overpredict the pollutant concentrations and loads. Continuous monitoring of nutrients and sediment has recently received more attention due to advances in computing, sensing technology, and storage devices. This protocol demonstrates the use of sensors, sondes, and instrumentation to continuously monitor in situ nitrate, ammonium, turbidity, pH, conductivity, temperature, and dissolved oxygen (DO) and to calculate the loads from two streams (ditches) in two agricultural watersheds. With the proper calibration, maintenance, and operation of sensors and sondes, good water quality data can be obtained by overcoming challenging conditions such as fouling and debris buildup. The method can also be used in watersheds of various sizes and characterized by agricultural, forested, and/or urban land.

With the advancement of technology and the rise in end-user expectations, the need and use of higher temporal resolution data for pollutant load estimation has increased. This protocol describes a method for continuous in situ water quality monitoring to obtain higher temporal resolution data for informed water resource management decisions.

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Composition and Properties of Aquafaba: Water Recovered from Commercially Canned Chickpeas

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce stable foams and emulsions, and can act as a thickener. Recently interest in this product has been enhanced through the internet where it is proposed that this solution, now called aquafaba by a growing community, can be used a replacement for egg and milk protein. As aquafaba is both new and being developed by an internet based community little is known of its composition or properties. Aquafaba was recovered from 10 commercial canned chickpea products and correlations among aquafaba composition, density, viscosity and foaming properties were investigated. Proton NMR was used to characterize aquafaba composition before and after ultrafiltration through membranes with different molecular weight cut offs (MWCOs of 3, 10, or 50 kDa). A protocol for electrophoresis, and peptide mass fingerprinting is also presented. Those methods provided valuable information regarding components responsible for aquafaba functional properties. This information will allow the development of practices to produce standard commercial aquafaba products and may help consumers select products of superior or consistent utility.

Aquafaba is a viscous juice from canned chickpea that, when stirred vigorously, produces a relatively stable white froth or foam. The primary research goal is to identify the components of aquafaba that contribute viscosifying/thickening properties using nuclear magnetic resonance (NMR), ultrafiltration, electrophoresis, and peptide mass fingerprinting.

Chickpea and other pulses are commonly sold as canned products packed in a thick solution or a brine. This solution has recently been shown to produce ...

Continuous Hydrologic and Water Quality Monitoring of Vernal Ponds

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. However, they are vulnerable parts of the landscapes that are often poorly understood and understudied. Land use and management practices, as well as climate change are thought to be a contribution to the global amphibian decline. However, more research is needed to understand the extent of these impacts. Here, we present methodology for characterizing a vernal pond's morphology and detail a monitoring station that can be used to collect water quantity and quality data over the duration of a vernal pond's hydroperiod. We provide methodology for how to conduct field surveys to characterize the morphology and develop stage-storage curves for a vernal pond. Additionally, we provide methodology for monitoring the water level, temperature, pH, oxidation-reduction potential, dissolved oxygen, and electrical conductivity of water in a vernal pond, as well as monitoring rainfall data. This information can be used to better quantify the ecosystem services that vernal ponds provide and the impacts of anthropogenic activities on their ability to provide these services.

Understanding the ecosystem services and processes provided by vernal ponds and the impacts of anthropogenic activities on their ability to provide these services requires intensive hydrologic monitoring. This sampling protocol using in-situ monitoring equipment was developed to understand the impact of anthropogenic activities on water levels and quality.

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. ...

Measuring Phosphorus Release in Laboratory Microcosms for Water Quality Assessment

Phosphorus (P) is a critical limiting nutrient in agroecosystems requiring careful management to reduce transport risk to aquatic environments. Routine laboratory measures of P bioavailability are based on chemical extractions performed on dried samples under oxidizing conditions. While useful, these tests are limited with respect to characterizing P release under prolonged water saturation. Labile orthophosphate bound to oxidized iron and other metals can rapidly desorb to solution in reducing environments, increasing P mobilization risk to surface runoff and groundwater. To better quantify P desorption potential and mobility during extended saturation, a laboratory microcosm method was developed based on repeated sampling of porewater and overlying floodwater over time. The method is useful for quantifying P release potential from soils and sediments varying in physicochemical properties and can improve site-specific P mitigation efforts by better characterizing P release risk in hydrologically active areas. Advantages of the method include its ability to simulate in situ dynamics, simplicity, low cost, and flexibility.

Accurate quantification of phosphorus (P) desorption potential in saturated soils and sediments is important for P modeling and transport mitigation efforts. To better account for in situ soil-water redox dynamics and P mobilization under prolonged saturation, a simple approach was developed based on repeated sampling of laboratory microcosms.

Phosphorus (P) is a critical limiting nutrient in agroecosystems requiring careful management to reduce transport risk to aquatic environments. Routine ...