USGS-NAWQA: BS0334: Benthic Macroinvertebrates: Preparing Microscope Slides
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Official Method Name
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Preparing Benthic Macroinvertebrate Microscope Slides |
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Current Revision
| 2011 |
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Media
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Biological (Waterbody type - Wadeable stream) |
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Instrumentation
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Microscope with fiber-optic illuminator |
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Method Subcategory
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Population/Community |
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Method Source
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Citation
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Protocol
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USGS NAWQA 2002 Eco Protocols - Revised Protocols for Sampling Algal, Invertebrate, and Fish Communities as Part of the National Water-Quality Assessment Program |
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Brief Method Summary
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The goal of this method is to standardize procedures used for the taxonomic identification of benthic macroinvertebrates (BMIs). These procedures can be applied to any BMI sample submitted to the National Water Quality Laboratory (NWQL) for analysis. Taxonomic identification of BMIs requires experienced personnel trained in zoological taxonomic principles and possessing a broad knowledge of all aquatic macroinvertebrate groups. Refer to the method document for steps on how to prepare the sample slide. |
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Scope and Application
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1.1. Certain groups of benthic macroinvertebrates (BMIs) (for example, Chironomidae larvae and Oligochaeta) are mounted on microscope slides prior to taxonomic identification. 1.2. These procedures are used by anyone responsible for preparing BMI microscope slides. 1.3. Organisms are oriented in mounting media on a microscope slide that is labeled with a unique sample identifier and slide number, covered with a coverslip, and dried. |
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Applicable Concentration Range
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Interferences
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4.2.1. Poor slide mounts often prevent a taxonomist from making identifications to the genus or species level. 4.2.2. Factors contributing to poorly prepared slides include: 4.2.2.1. improper orientation of the organism on the slide 4.2.2.2. mounting too many organisms for one cover slip 4.2.2.3. mounting an organism too large for one coverslip 4.2.2.4. improper clearing action 4.2.2.5. high-viscosity of the mounting medium 4.2.2.6. air bubbles forming beneath cover slips |
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Quality Control Requirements
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5.1. Inspect all dishes before preparing slides; make sure there are no organisms or sample debris remaining from previously processed slides. 5.2. Make sure slide and cover slips are not broken. 5.3. Check the viscosity of the mounting medium. 5.4. Inspect prepared slides to evaluate the orientation of the mounted organisms. |
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Sample Handling
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Refer to NWQL SOP No. BS0331.0. for sample preparation. |
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Maximum Holding Time
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Relative Cost
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Unknown |
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Sample Preparation Methods
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see method documentation PDF |
