This research was funded by the U.S. Army Corps of Engineers Dredging Operations and Environmental Research Program, Todd Bridges, Director. Permission was granted by the Chief of Engineers to publish this material.

<ol><li>National Research Council (NRC). A process for setting, managing, and monitoring environmental windows for dredging projects. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=%22Marine+Board%2C+Transportation+Research+Board%2C+Special+Report+262%22">Marine Board, Transportation Research Board, Special Report 262</a>. , National Academy Press. Washington, DC. (2001).</li>
<li>Suedel, B. C., Kim, J., Clarke, D. G., Linkov, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+risk-informed+decision+framework+for+setting+environmental+windows+for+dredging+projects%5BTitle%5D)+AND+%22Sci+Total+Environ%22%5BJournal%5D)">A risk-informed decision framework for setting environmental windows for dredging projects.</a> Sci Total Environ. 403, 1-11 (2008).</li>
<li>Reine, K. J., Dickerson, D. D., Clarke, D. G. Environmental windows associated with dredging operations. DOER Technical Notes Collection. ERDC TN DOER-E2. , U.S. Army Engineer Research and Development. Vicksburg, MS. (1998).</li>
<li>Wilber, D. H., Clarke, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Biological+effects+of+suspended+sediments%3A+A+review+of+suspended+sediment+impacts+on+fish+and+shellfish+with+relation+to+dredging+activities+in+estuaries%5BTitle%5D)+AND+%22N+Am+J+Fish+Manag%22%5BJournal%5D)">Biological effects of suspended sediments: A review of suspended sediment impacts on fish and shellfish with relation to dredging activities in estuaries.</a> N Am J Fish Manag. 21, 855-875 (2001).</li>
<li>Suedel, B. C., Lutz, C. H., Clarke, J. U., Clarke, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effects+of+suspended+sediment+on+walleye+%28Sander+vitreus%29+eggs%5BTitle%5D)+AND+%22J.+Soils+Sediments%22%5BJournal%5D)">The effects of suspended sediment on walleye (Sander vitreus) eggs.</a> J. Soils Sediments. 12, 995-1003 (2012).</li>
<li>Travis, J., Kring, J. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aTravis%2C+J+%22LabVIEW+for+Everyone%3A+Graphical+Programming+Made+Easy+and+Fun+%28National+Instruments+Virtual+Instrumentation+Series%29%22">LabVIEW for Everyone: Graphical Programming Made Easy and Fun (National Instruments Virtual Instrumentation Series)</a>. , Prentice Hall PTR. (2006).</li>
<li>USEPA, Hazardous Waste Test Methods/SW-846 On-line. Office of Solid Waste and Emergency Response (OSWER). , Washington, D.C. Available from:
 <a target="_blank" href="https://www.epa.gov/hw-sw846/sw-846-compendium">https://www.epa.gov/hw-sw846/sw-846-compendium</a> (2016).</li>
<li>Plumb, R. H. Procedure for handling and chemical analysis of sediment and water samples, EPA/CE-81-1. , U.S. Environmental Protection Agency/U.S. Army Engineer Waterways Experiment Station. Vicksburg, MS. Technical Report (1981).</li>
<li>Clarke, D. G., Wilber, D. H. Assessment of potential impacts of dredging operations due to sediment resuspension. , DOER Technical Notes Collection(TN-DOER-E9), U.S. Army Engineer Research and Development. Center, Vicksburg, MS. Available from:
 <a target="_blank" href="http://el.erdc.usace.army.mil/dots/doer/pdf/doere9.pdf">http://el.erdc.usace.army.mil/dots/doer/pdf/doere9.pdf</a> (2000).</li>
<li>Suedel, B. C., Clarke, J. U., Lutz, C. H., Clarke, D. G., Godard-Codding, C., Maul, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Suspended+sediment+effects+on+walleye+%28Sander+vitreus%29%5BTitle%5D)+AND+%22J.+Great+Lakes+Res%22%5BJournal%5D)">Suspended sediment effects on walleye (Sander vitreus).</a> J. Great Lakes Res. 40, 141-148 (2014).</li>
<li>Wilkens, J. L., Katzenmeyer, A. W., Hahn, N. M., Hoover, J. J., Suedel, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Laboratory+test+of+suspended+sediment+effects+on+short-term+survival+and+swimming+performance+of+juvenile+Atlantic+Sturgeon+%28Acipenser+oxyrinchus+oxyrinchus%29%5BTitle%5D)+AND+%22J.+Appl.+Ichthy%22%5BJournal%5D)">Laboratory test of suspended sediment effects on short-term survival and swimming performance of juvenile Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus).</a> J. Appl. Ichthy. 31, 984-990 (2015).</li>
<li>Suedel, B. C., Clarke, J. U., Wilkens, J., Lutz, C. H., Clarke, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effects+of+a+simulated+sediment+plume+on+eastern+oyster+%28Crassostrea+virginica%29+survival%2C+growth%2C+and+condition%5BTitle%5D)+AND+%22Estuaries+and+Coasts%22%5BJournal%5D)">The effects of a simulated sediment plume on eastern oyster (Crassostrea virginica) survival, growth, and condition.</a> Estuaries and Coasts. 38 (2), 578-589 (2015).</li>
<li>Bilotta, G. S., Brazier, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Understanding+the+influence+of+suspended+solids+on+water+chemistry+and+aquatic+biota%5BTitle%5D)+AND+%22Water+Res%22%5BJournal%5D)">Understanding the influence of suspended solids on water chemistry and aquatic biota.</a> Water Res. 42, 2849-2861 (2008).</li>
<li>Reine, K., Clarke, D., Dickerson, C., Pickard, S. Assessment of potential impacts of bucket dredging plumes on walleye spawning habitat in Maumee Bay, Ohio. Proceedings of the 18th World Dredging Congress (WODCON XVIII). , Lake Buena Vista, FL, USA . (2007).</li>
</ol>

Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the U.S. Army. Citations of commercial organizations or trade names in this report do not constitute an official Department of the Army endorsement or approval of the products or services of these organizations. Authors Burton C. Suedel and Justin L. Wilkens, both of the US Army Engineer Research and Development Center, declare that they have no competing financial interests.

The FLEES technology improves on existing methods4,9 by maintaining and controlling suspended sediments over a wide range of exposure times and suspended sediment concentrations using an automated, computer controlled system. The technology is flexible such that it can be used to evaluate the effects of suspended sediments to multiple aquatic species and life stages of varying sizes from eggs to adults depending on the species. In the future, the technology is capable of assessing suspended sediment effects to submerged aquatic vegetation.
The FLEES has been used to successfully generate effects data (e.g., survival and growth) for various species such as walleye5,10, Atlantic sturgeon11 and oysters12. The FLEES performed as designed in evaluating the effects of different suspended sediments collected from various locations across the United States on aquatic species from both freshwater and marine environments. The portability and packaging of the technology also makes it conducive to field use.
The most critical steps in the methodology to ensure success are to: 1) calibrate the FLEES with every test sediment so the relationship between TSS and turbidity can be quantified, thereby enabling matching target TSS concentrations; 2) performing experiments based on TSS and not turbidity so that experimental results can be compared to appropriate regulatory criteria and standards; 3) use the appropriate double-diaphragm pump so that the sediment/water slurry can be routed without ruining the pump; 4) use sediments considered chemically uncontaminated so that the physical effects of suspended sediment is not confounded by chemical contamination.
The technology measures turbidity as NTUs in each aquarium via OBS mounted in each aquarium, yet there are distinct and significant differences between the two measurements9. Suspended sediment measurements detect particles that have mass, and is often measured gravimetrically or with acoustic technologies. Turbidity is a measure of clarity that is measured as light scattered by material in a water sample by a nephelometer. While turbidity is an important factor in describing suspended sediments, it is influenced by sediment particle size, shape, and number and therefore can vary widely in the environment and from experiment to experiment when using different sediments. For experiments using the technology, TSS measurements (mg/L) are used to develop exposure concentrations because they quantify the mass of particles present in the water column and directly relate to effects in aquatic organisms4. TSS is also the unit of measure regulatory bodies use to set environmental windows thresholds for turbidity.
There are some limits to this technology in the maximum quantity of suspended sediment it can transport. Based on experiments conducted to date, TSS concentrations have been successfully maintained up to 600 mg/L. FLEES has continuously produced up to 600 NTUs for seven continuous days and 10-30 NTUs for 30 continuous days with minimal pump maintenance. While the FLEES can maintain TSS concentrations approaching 800 mg/L, concentrations exceeding this amount would require a slurry holding tank of increased capacity. Suspended sediment concentrations exceeding about 800 mg/L would also potentially result in larger particles dropping out of suspension, resulting in NTU readings that do not accurately reflect actual exposure. Nonetheless, concentrations up to 500 to 600 mg/L are considered the maximum concentration expected directly adjacent to an operating dredge, so greater concentrations are not relevant to most dredging operations4.
Another limit to this technology is the sediment grain size distribution. Particle sizes greater than about 250 &#181;m need to be sieved before use so that larger particles do not tax the pump or settle in the aquaria. Such limitations are not considered significant because it is the finer silt and clay particles that migrate farthest from the source and thus have the greatest potential to cause harm to aquatic animals. While the computer program can be programmed to yield continuous suspended sediment concentrations in each aquarium, it also can be programmed to vary or pulse depending on experimental objectives. In some cases, however, sediment with high percentage clay fraction may not settle sufficiently to adequately mimic a pulsed exposure.
The automation and programming features of the FLEES results in a system that can accurately and precisely maintain TSS levels as well as introduce clean water. Because of these features, FLEES can be easily modified to meet other experimental needs. For example, each FLEES aquarium can be treated as a slurry reservoir and from it slurry may be introduced into another exposure chamber outside of the aquarium. If larger exposure aquaria are desired then the system can be scaled up to meet these needs. FLEES tanks may also be retrofitted to study the effects of sedimentation.
FLEES is a durable system and requires minimal maintenance. Aquarium pump housings can be used multiple times before needing maintenance. The housing should be dissembled, cleaned an inspected after each experiment. Typically the impeller is the first part to fail followed eventually by the remainder of the housing. The air-operated double-diaphragm pump is quite durable and generally does not require inspection after each experiment; however, it is recommended, depending on use, that it be inspected at least annually. The pump manufacturer usually provides a repair kit for commonly worn parts. Clean water should be pumped through the slurry line after each experiment to remove remaining slurry and to clean out the solenoid valves. The remainder of FLEES, including aquaria, water baths and reservoirs should be cleaned following appropriate laboratory procedures.
The FLEES is designed for transport to other sites. The plumbing, electrical, and data connections between each module are made with unions or plugs so they may be easily disconnected for transport and reconnected at a new location. Once transported, the FLEES can utilize a local water source which may be required to meet specific experimental needs. This feature allows for testing of aquatic species that may otherwise be unachievable due to transport limitations or survivability in a laboratory environment.
This paper describes an automated laboratory system designed to evaluate the effects of suspended sediment on various aquatic species. The FLEES technology is capable of exposing aquatic organisms to TSS concentrations reflecting dredging operations, vessel traffic, freshets, and storms14. This technology can be used by any investigator interested in answering questions about the effects of sediment suspended in surface water bodies on aquatic species.

Dredging operations use mechanical methods to remove bottom sediments from harbors and navigation channels. During removal, some portion of the disturbed sediment is suspended into the water column, potentially making this a source of physical stress to aquatic species. In addition to being suspended, the sediment may be transported away from the dredge by ambient conditions before settling out of the water column. The combination of these two mechanisms means that an aquatic organism occurring near an operating dredge may be exposed to suspended sediments and suffer adverse effects. To address such concerns, environmental windows (seasonal dredging restrictions) are routinely used as a management practice to reduce or eliminate risk of potentially harmful impacts of suspended sediments from dredging activities on aquatic resources1,2.
Environmental windows are most commonly established to protect endangered, threatened or commercially valuable species such as the walleye (Sander vitreus) and eastern oyster (Crassostrea virginica)3. The supporting justification for imposing environmental windows often focuses on how dredge activities may potentially physically disturb (e.g., suspended sediment) an animal&#39;s ability to complete a specific part of its life history. The life stages commonly cited are eggs and larvae for keeping migration routes open for anadromous species3. However, there is limited information concerning species-specific biological effects relevant to suspended sediment4,5 available to inform using environmental windows as a risk management tool.
For these reasons, the FLEES was designed, built, and used to simulate the suspension of sediment, and to determine its effects on early life stages of aquatic organisms. FLEES studies use fine-grained sediment particles (i.e., predominantly silts, clays, and fine sands) which are most likely to remain in suspension and migrate furthest from the source. The FLEES is capable of testing fish eggs and larvae, but it can also be retrofitted to accommodate other aquatic organisms, making it a unique capability. The resulting biological response data can then be used to assess the effects of suspended sediments. The following procedures provide an overview of how the technology can be constructed and operated to yield repeatable suspended sediment concentrations and effects data using various aquatic species.

<table><tbody><tr><td colspan="4">&lt;strong&gt;Parts List for One FLEES Module, Water Bath, and Aquarium&lt;/strong&gt;</td></tr><tr><td>post, wood - used to build module (cut to 78 in)</td><td>Local vendor</td><td>N/A</td><td>Quantity: 4&lt;br/&gt; Size: 4 in x 4 in x 8 ft</td></tr><tr><td>plywood, marine grade - fastened to wooden posts about 18 in off ground - for holding water bath (60 in x 42 in)</td><td>Local vendor</td><td>N/A</td><td>Quantity: 1&lt;br/&gt; Size: 3/4 in x 4 ft x 8 ft</td></tr><tr><td>plywood - fastened on top of wooden posts - for holding pipes, solenoids and electrical (60 in x 42 in)</td><td>Local vendor</td><td>N/A</td><td>Quantity: 1&lt;br/&gt; Size: 1/4 in x 4 ft x 8 ft</td></tr><tr><td>stud, wood - used to brace plywood and wooden posts (cut to fit)</td><td>Local vendor</td><td>N/A</td><td>Quantity: 4&lt;br/&gt; Size: 2 in x 4 in x 96 in</td></tr><tr><td>tank, fiberglass - water bath with two drains: 1) to supply chiller; and 2) to drain water</td><td>Hydro Composites, LLC, Stockdale, TX, USA</td><td>FBT-226</td><td>Quantity: 1&lt;br/&gt; Size: 150-gal</td></tr><tr><td>chiller, water with self contained pump - for water bath; chiller sits under module</td><td>Remcor Products Co., Glendale Heights, IL, USA</td><td>CFF-500</td><td>Quantity: 1&lt;br/&gt; Size: 1/2 hp</td></tr><tr><td>tank, domed bottom - FLEES aquaria - sit inside water bath</td><td>United States Plastic Corp, Lima, OH, USA</td><td>5197</td><td>Quantity: 5&lt;br/&gt; Size: 19 L</td></tr><tr><td>tank, stand - acrylic stand, 12 in x 12 in x 6 in - to hold aquaria</td><td>custom built by ERDC shops</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: custom</td></tr><tr><td>pump, magnetic drive - to suspend sediment in each aquarium</td><td>March Manufacturing Inc., Glenview, IL, USA</td><td>MDX-3-1/2 115 v</td><td>Quantity: 5&lt;br/&gt; Size: 28 liter per min</td></tr><tr><td>light, LED - installed over water bath</td><td>C2 Development, Inc., Ames, IA, USA</td><td>Hydra 26</td><td>Quantity: 2&lt;br/&gt; Size: based on area to light</td></tr><tr><td>pipe, PVC schedule 40 - installed in drain of water bath to control water level</td><td>Local vendor</td><td>N/A</td><td>Quantity: -&lt;br/&gt; Size: 1 in</td></tr><tr><td>fittings, bulkhead - for aquaria/water bath connections to pumps, drains, water and slurry lines</td><td>Lifegard Aquatics, Cerritos, CA, USA</td><td>R270900</td><td>Quantity: 30&lt;br/&gt; Size: 1/2 in FPT x FPT</td></tr><tr><td>fittings, quick-disconnect, male pipe threaded inserts - insert in tank bulkhead</td><td>Cole-Parmer, Vernon Hills, IL, USA</td><td>EW-31303-36</td><td>Quantity: 10&lt;br/&gt; Size: 1/2 in MPT</td></tr><tr><td>fittings, quick-disconnect, valved hose barbs - connection between aquarium and insert in tank bulkhead</td><td>Cole-Parmer, Vernon Hills, IL, USA</td><td>EW-31303-11</td><td>Quantity: 10&lt;br/&gt; Size: 1/2 in</td></tr><tr><td>fittings, black HDPE threaded elbow - for aquaria vinyl tube connections to slurry/water line and pump</td><td>United States Plastic Corp, Lima, OH, USA</td><td>62043</td><td>Quantity: 20&lt;br/&gt; Size: 1/2 NPT x 1/2 in Hose ID</td></tr><tr><td>fittings, black HDPE threaded adapter - for connections between pump and tank bulkhead</td><td>United States Plastic Corp, Lima, OH, USA</td><td>62017</td><td>Quantity: 10&lt;br/&gt; Size: 1/2 NPT x 1/2 in Hose ID</td></tr><tr><td>tube, vinyl - connect slurry/water line to aquaria and to connect pumps to aquaria</td><td>Local vendor</td><td>N/A</td><td>Quantity: 25 ft&lt;br/&gt; Size: 1/2 in ID</td></tr><tr><td>tube, vinyl - connect to aquaria drains inserts and water bath drain</td><td>Local vendor</td><td>N/A</td><td>Quantity: 25 ft&lt;br/&gt; Size: 5/8 in ID</td></tr><tr><td>clamp, hose, stainless steel - to clamp vinyl tube to hose barbs</td><td>Local vendor</td><td>N/A</td><td>Quantity: 40&lt;br/&gt; Size: #8</td></tr><tr><td colspan="4">&lt;strong&gt;Parts List for Slurry System&lt;/strong&gt;</td></tr><tr><td>chiller, water with self contained pump - sits off to side of slurry tank</td><td>Remcor Products Co., Glendale Heights, IL, USA</td><td>CFF-500</td><td>Quantity: 1&lt;br/&gt; Size: 1/2 hp</td></tr><tr><td>125 gallon open top cone bottom tank w/Stand - 42 in x 35 in - contains the water and sediment to make slurry</td><td>United States Plastic Corp, Lima, OH, USA</td><td>8586</td><td>Quantity: 1&lt;br/&gt; Size: 125 gal</td></tr><tr><td>Cover for 125 gallon tank</td><td>United States Plastic Corp, Lima, OH, USA</td><td>8935</td><td>Quantity: 1&lt;br/&gt; Size: 42 in x 35 in</td></tr><tr><td>valve, PVC - connect tank drain to pump - isolate for maintenance</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 2&lt;br/&gt; Size: 1-1/2 in</td></tr><tr><td>pump, double diaphragm mounted on stand - used to recirculate slurry</td><td>Wilden-pumps.co.uk &amp;amp; Air Pumping Ltd., Essex, UK</td><td>P2/PPPP/WF/WF/PTV/400</td><td>Quantity: 1&lt;br/&gt; &lt;br/&gt; contact distributor</td></tr><tr><td>sensor, optical backscatter - measure NTU in slurry tank</td><td>Campbell Scientific, Logan, UT, USA</td><td>OBS-3+</td><td>Quantity: 1&lt;br/&gt; Size: 0-1,000 NTU</td></tr><tr><td>pipe, PVC Schedule 40 - to recirculate slurry</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 20 ft&lt;br/&gt; Size: 1 in</td></tr><tr><td>pipe, flexible PVC - fitted with union and used to connect to next module</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 10 ft&lt;br/&gt; Size: 1 in</td></tr><tr><td>union, PVC Schedle 80 Socket - connect slurry line with next module</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 8&lt;br/&gt; Size: 1/2 in</td></tr><tr><td>solenoid, plastomatic (normally closed) - introduce slurry</td><td>Plast-O-Matic Valves, Inc., Cedar Grove, NJ, USA</td><td>EASYMT4V12R24-PV</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in NPT threaded, 24 VAC&lt;br/&gt; contact distributor</td></tr><tr><td>fitting, PVC tee - connect slurry pipe with solenoid</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1 in x 1 in x 1 in slip x slip x FIPT</td></tr><tr><td>fittings, 1 in PVC ball valve threaded - shut off for slurry delivery to solenoid/water lines</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 7&lt;br/&gt; Size: 1/2 in</td></tr><tr><td>fittings, 1 in PVC union threaded - connect slurry solenoid to shut off valve</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in</td></tr><tr><td>tube, vinyl - connection between water solenoid and slurry solenoid</td><td>Local vendor</td><td>N/A</td><td>Quantity: 50 ft&lt;br/&gt; Size: 1/4&quot; ID</td></tr><tr><td colspan="4">&lt;strong&gt;Parts List for Water System&lt;/strong&gt;</td></tr><tr><td>chiller, water with self contained pump - sits off to side of reservoir</td><td>Remcor Products Co., Glendale Heights, IL, USA</td><td>CFF-500</td><td>Quantity: 1&lt;br/&gt; Size: 1/2 hp</td></tr><tr><td>125 gallon open top cone bottom tank w/Stand - 42 in x 35 in - contains the water and sediment to make slurry</td><td>United States Plastic Corp, Lima, OH, USA</td><td>8586</td><td>Quantity: 1&lt;br/&gt; Size: 125 gal</td></tr><tr><td>Cover for 125 gallon tank</td><td>United States Plastic Corp, Lima, OH, USA</td><td>8935</td><td>Quantity: 1&lt;br/&gt; Size: 42 in x 35 in</td></tr><tr><td>valve, PVC - connect tank drain to water pump</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 2&lt;br/&gt; Size: 1 in</td></tr><tr><td>pump, magnetic drive, in-line use - used to recirculate water to aquaria and chiller</td><td>Little Giant, Fort Wayne, IN, USA</td><td>3-MD-SC</td><td>Quantity: 1&lt;br/&gt; Size: 1/12 hp</td></tr><tr><td>solenoid, alco - introduce water</td><td>discontinued; ASCO, Florham Park, NJ,USA for similar</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 24 v, 1/4 in NIPT</td></tr><tr><td>fittings, black HDPE reducer connector - connect 1/4 in hose water line from solenoid&amp;nbsp; to 1/2 in hose</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in hose ID x 1/4 in hose ID</td></tr><tr><td>fittings, black HDPE tee - connect 1/2 in hose water line and slurry to aquaria</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in NPT x 1/2 in hose ID x 1/2 in hose ID</td></tr><tr><td>fittings, street elbow</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in 90&amp;deg; MIPT x FIPT</td></tr><tr><td>fittings, PVC threaded pipe nipples - connect union fittings with solenoids and other connections</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 12&lt;br/&gt; Size: 1/2 in</td></tr><tr><td>fittings, union threaded - connect slurry/water lines with next module</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 6&lt;br/&gt; Size: 1 in PVC&amp;nbsp;</td></tr><tr><td>fittings, reducer bushing - connect to reducer tee in water line</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 1/2 in male by 1/4 in female FIPT</td></tr><tr><td>fittings, threaded pipe nipples - connection between bushing and water solenoid</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5&lt;br/&gt; Size: 4 in long x 1/4 in</td></tr><tr><td>pipe, PVC - make connections between tank, pump and chiller</td><td>local plumbing vendor</td><td>N/A</td><td>Quantity: 5 ft&lt;br/&gt; Size: Schedule 40</td></tr><tr><td colspan="4">&lt;strong&gt;Parts List for Sensors, Data Acquisition Device, and Computer Software&lt;/strong&gt;</td></tr><tr><td>software, LabView</td><td>National Instruments, Austin, Texas, USA</td><td>LabView 2015 Base</td><td>Quantity: 1&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI-1001 12-Slot Chassis, U.S. 120 VAC</td><td>National Instruments, Austin, Texas, USA</td><td>776571-01</td><td>Quantity: 1&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI 1100 - 32-Channel, &amp;plusmn;10 V Analog Input Module</td><td>National Instruments, Austin, Texas, USA</td><td>776572-00</td><td>Quantity: 1&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI 1303 - Terminal block designed for high-accuracy thermocouple measurements</td><td>National Instruments, Austin, Texas, USA</td><td>777687-03</td><td>Quantity: 2&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI 1102B - 32-Channel Thermocouple/Voltage Input Module</td><td>National Instruments, Austin, Texas, USA</td><td>776572-02B</td><td>Quantity: 1&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI 1161 - General-Purpose Relay Module</td><td>National Instruments, Austin, Texas, USA</td><td>776572-61</td><td>Quantity: 6&lt;br/&gt; Size: N/A</td></tr><tr><td>SCXI 1300 - General-Purpose Voltage Module</td><td>National Instruments, Austin, Texas, USA</td><td>777687-00</td><td>Quantity: 1&lt;br/&gt; Size: N/A</td></tr><tr><td>PCMCIA Card DAQCARD-AI-16E-4</td><td>National Instruments, Austin, Texas, USA</td><td>N/A - legacy</td><td>Quantity: 1&lt;br/&gt; Size: N/A&lt;br/&gt; used cards available online</td></tr><tr><td>sensor, optical backscatter - measure NTU in each aquarium</td><td>Campbell Scientific Inc., Logan, UT, USA</td><td>OBS-3+</td><td>Quantity: 5&lt;br/&gt; Size: 0-1,000 NTU</td></tr></tbody></table>

a flow-through exposure system for evaluating suspended sediments effects on aquatic life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A series of operational runs is performed before beginning an experiment to ensure that the FLEES is delivering the appropriate concentrations of sediments to each aquarium (Sections 5.5 and 6.2). Figure 6 illustrates how NTU concentrations are maintained in experimental aquaria to achieve target suspended sediment concentrations. In this example, FLEES evaluated whether suspended sediment could be maintained over a three-day period with the proposed test sediment, a duration of exposure typical for such experiments simulating typical exposures in the field. Each of the aquaria was set to consistently maintain a turbidity over the three-day period. Test sediments were introduced over a 4 h period on 30th May 2016. The 0 mg/L TSS concentration represented a control aquarium with no added sediment. At the 100, 250, and 500 mg/L target concentrations, aquaria consistently maintained turbidity of 90, 240, and 430 NTU, respectively, over the three-day experimental period (Figure 6). Sediment pulses reflective of programmed and timed additions of suspended sediment are visible at each concentration in the graph. The flexibility of the FLEES allows investigators to come within about 20-40 NTU of the target concentration. These data demonstrate the ability of the FLEES technology to maintain the desired suspended sediment concentration over time.
<img alt="Figure 6" src="/files/ftp_upload/54937/54937fig6.jpg" /> 
Figure 6. Representative FLEES results at four suspended sediment concentrations. Nephelometric turbidity unit (NTU) data recorded by FLEES computer software at 5 min intervals over a 3-day period during an experiment designed to achieve 0, 100, 250 and 500 mg/L total suspended solids concentrations. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54937/54937fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Similarly, Figure 7 shows the results of how TSS concentration can be maintained at considerably lower concentrations representing ambient conditions.
<img alt="Figure 7" src="/files/ftp_upload/54937/54937fig7.jpg" /> 
Figure 7. Representative FLEES results near ambient conditions. Nephelometric turbidity unit (NTU) data recorded by FLEES computer software at 5 min intervals over a 7 day period during an experiment designed to achieve 25 NTU, equivalent of 20 mg/L TSS for the test sediment. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54937/54937fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The FLEES is calibrated using test sediment to quantify the relationship between TSS and turbidity to ensure target TSS concentrations are achieved (Sections 5.4 and 5.5.2). Figure 8 illustrates the relationship between NTU and TSS for an example test sediment evaluated in the FLEES. In this example, the test sediment exhibited consistently higher NTU values relative to each corresponding TSS concentration evaluated. These data can then be used to calibrate the FLEES and report results in TSS for subsequent appropriate evaluation of effects.
<img alt="Figure 8" src="/files/ftp_upload/54937/54937fig8.jpg" /> 
Figure 8. The NTU-TSS relationship for an example test sediment. The targeted TSS treatment concentrations were 0 (control), 100, 250 and 500 mg/L. Error bars represent the SEM. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54937/54937fig8large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

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A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

a-flow-through-exposure-system-for-evaluating-suspended-sediments

Nanyang Technological University

Research

JoVE Journal

Environment

8.4K Views.  U.S. Army Corps of Engineers. A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

Video: A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

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 Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Here, we present small core incubations for the measurement of sediment-water gas and solute exchange. These will provide reliable measurements of sediment-water exchange that assess the role of sediment in influencing biological and biogeochemical processes in aquatic ecosystems.

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in ...

VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders

Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and detritus, and excreting particulate and dissolved compounds, they serve as important agents for benthic-pelagic coupling. Accurately measuring the compounds removed and excreted by suspension feeders (such as sponges, ascidians, polychaetes, bivalves) is crucial for the study of their physiology, metabolism, and feeding ecology, and is fundamental to determine the ecological relevance of the nutrient fluxes mediated by these organisms. However, the assessment of the rate by which suspension feeders process particulate and dissolved compounds in nature is restricted by the limitations of the currently available methodologies. Our goal was to develop a simple, reliable, and non-intrusive method that would allow clean and controlled water sampling from a specific point, such as the excurrent aperture of benthic suspension feeders, in situ. Our method allows simultaneous sampling of inhaled and exhaled water of the studied organism by using minute tubes installed on a custom-built manipulator device and carefully positioned inside the exhalant orifice of the sampled organism. Piercing a septum on the collecting vessel with a syringe needle attached to the distal end of each tube allows the external pressure to slowly force the sampled water into the vessel through the sampling tube. The slow and controlled sampling rate allows integrating the inherent patchiness in the water while ensuring contamination free sampling. We provide recommendations for the most suitable filtering devices, collection vessel, and storing procedures for the analyses of different particulate and dissolved compounds. The VacuSIP system offers a reliable method for the quantification of undisturbed suspension feeder metabolism in natural conditions that is cheap and easy to learn and apply to assess the physiology and functional role of filter feeders in different ecosystems.

VacuSIP, an Improved InEx Method for In Situ Measurement of Particulate and Dissolved Compounds Processed by Active Suspension Feeders

We introduce the VacuSIP, a simple, non-intrusive, and reliable method for clean and accurate point sampling of water. The system was developed and evaluated for the simultaneous collection of the water inhaled and exhaled by benthic suspension feeders in situ, to cleanly measure removal and excretion of particulate and dissolved compounds.

Benthic suspension feeders play essential roles in the functioning of marine ecosystems. By filtering large volumes of water, removing plankton and ...

Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may be treated with simple systems designed to promote sorption of contaminants to vegetation and soils and promote infiltration. Two example systems are described: a bioswale treatment system for urban stormwater treatment, and a vegetated drainage ditch for treating agriculture irrigation runoff. Both have similar attributes that reduce contaminant loading in runoff: vegetation that results in sorption of the contaminants to the soil and plant surfaces, and water infiltration. These systems may also include the integration of granulated activated carbon as a polishing step to remove residual contaminants. Implementation of these systems in agriculture and urban watersheds requires system monitoring to verify treatment efficacy. This includes chemical monitoring for specific contaminants responsible for toxicity. The current paper emphasizes monitoring of current use pesticides since these are responsible for surface water toxicity to aquatic invertebrates.

This article summarizes the design attributes and the effectiveness of treatment systems that treat urban stormwater and agriculture irrigation runoff to remove pesticides and other contaminants associated with aquatic toxicity.

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may ...

Image-based Lagrangian Particle Tracking in Bed-load Experiments

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a relatively low cost. This manuscript describes an application of particle tracking velocimetry (PTV) to a bed-load experiment with lightweight sediment. The key characteristics of the investigated sediment transport conditions were the presence of a covered flow and of a fixed rough bed above which particles were released in limited number at the flume inlet. Under the applied flow conditions, the motion of the individual bed-load particles was intermittent, with alternating movement and stillness terms. The flow pattern was preliminarily characterized by acoustic measurements of vertical profiles of the stream-wise velocity. During process visualization, a large field of view was obtained using two action-cameras placed at different locations along the flume. The experimental protocol is described in terms of channel calibration, experiment realization, image pre-processing, automatic particle tracking, and post-processing of particle track data from the two cameras. The presented proof-of-concept results include probability distributions of the particle hop length and duration. The achievements of this work are compared to those of existing literature to demonstrate the validity of the protocol.

The manuscript presents a protocol for the conduction of bed-load sediment transport experiments where the moving particles are tracked by image analysis. The experimental facility, the procedures for run realization and data processing, and finally some proof-of-concept results are presented here.

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a ...

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.

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 ...

Determination of the Settling Rate of Clay/Cyanobacterial Floccules

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.

The interaction and sedimentation of the clay and bacterial cells within the marine realm, observed in natural environments, can be best investigated in a controlled lab environment. Here, we describe a detailed protocol, which outlines a novel method for measuring the sedimentation rate of clay and cyanobacterial floccules.

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction ...

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

Knowledge of habitat suitability for freshwater mussels is an important step in the conservation of this endangered species group. We describe a protocol for performing in situ juvenile exposure tests within oligotrophic river catchments over one-month and three-month periods. Two methods (in both modifications) are presented to evaluate the juvenile growth and survival rate. The methods and modifications differ in value for the locality bioindication and each has its benefits as well as limitations. The sandy cage method works with a large set of individuals, but only some of the individuals are measured and the results are evaluated in bulk. In the mesh cage method, the individuals are kept and measured separately, but a low individual number is evaluated. The open water exposure modification is relatively easy to apply; it shows the juvenile growth potential of sites and can also be effective for water toxicity testing. The within-bed exposure modification needs a high workload but is closer to the conditions of a natural juvenile environment and it is better for reporting the real suitability of localities. On the other hand, more replications are needed in this modification due to its high-hyporheic environment variability.

Bioindication Testing of Stream Environment Suitability for Young Freshwater Pearl Mussels Using In Situ Exposure Methods

In situ bioindications enable determination of the suitability of an environment for endangered mussel species. We describe two methods based on the juvenile exposure of freshwater pearl mussels in cages to oligotrophic river habitats. Both methods are implemented in variants for open water and hyporheic water environments.

Knowledge of habitat suitability for freshwater mussels is an important step in the conservation of this endangered species group. We describe a protocol ...

Window on a Microworld: Simple Microfluidic Systems for Studying Microbial Transport in Porous Media

Microbial growth and transport in porous media have important implications for the quality of groundwater and surface water, the recycling of nutrients in the environment, as well as directly for the transmission of pathogens to drinking water supplies. Natural porous media is composed of an intricate physical topology, varied surface chemistries, dynamic gradients of nutrients and electron acceptors, and a patchy distribution of microbes. These features vary substantially over a length scale of microns, making the results of macro-scale investigations of microbial transport difficult to interpret, and the validation of mechanistic models challenging. Here we demonstrate how simple microfluidic devices can be used to visualize microbial interactions with micro-structured habitats, to identify key processes influencing the observed phenomena, and to systematically validate predictive models. Simple, easy-to-use flow cells were constructed out of the transparent, biocompatible and oxygen-permeable material poly(dimethyl siloxane). Standard methods of photolithography were used to make micro-structured masters, and replica molding was used to cast micro-structured flow cells from the masters. The physical design of the flow cell chamber is adaptable to the experimental requirements: microchannels can vary from simple linear connections to complex topologies with feature sizes as small as 2 &mu;m. Our modular EcoChip flow cell array features dozens of identical chambers and flow control by a gravity-driven flow module. We demonstrate that through use of EcoChip devices, physical structures and pressure heads can be held constant or varied systematically while the influence of surface chemistry, fluid properties, or the characteristics of the microbial population is investigated. Through transport experiments using a non-pathogenic, green fluorescent protein-expressing Vibrio bacterial strain, we illustrate the importance of habitat structure, flow conditions, and inoculums size on fundamental transport phenomena, and with real-time particle-scale observations, demonstrate that microfluidics offer a compelling view of a hidden world.

Microfluidic devices can be used to visualize complex natural processes in real time and at the appropriate physical scales. We have developed a simple microfluidic device that mimics key features of natural porous media for studying growth and transport of bacteria in the subsurface.

Microbial growth and transport in porous media have important implications for the quality of groundwater and surface water, the recycling of nutrients in ...

Biology

Quantifying Fish Swimming Behavior in Response to Acute Exposure of Aqueous Copper Using Computer Assisted Video and Digital Image Analysis

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors.

Measuring the impacts of environmental contaminants on fish behavior is often subjective and challenging particularly when dealing with sublethal endpoints. We describe methods including video technology to quantify swimming behavior of early life stage white sturgeon (Acipenser transmontanus) during and after 96 hr acute exposures to various concentrations of copper.

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction.  ...

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

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