http://lod.bco-dmo.org/id/dataset/780043 eng; USA utf8 dataset Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact 2019-10-29 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Relative crab mortality (binomial) data from a tethering experiment in summer 2017 in Back Sound, North Carolina 2019-02-11 publication 2019-02-11 revision Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA) 2020-02-11 publication https://doi.org/10.1575/1912/bco-dmo.780043.2 F. Joel Fodrie University of North Carolina at Chapel Hill principalInvestigator Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. publisher Cite this dataset as: Fodrie, F. (2019) Relative crab mortality (binomial) data from a tethering experiment in summer 2017 in Back Sound, North Carolina. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2019-11-06 [if applicable, indicate subset used]. doi:10.1575/1912/bco-dmo.780043.1 [access date] Dataset Description: &lt;p&gt;Relative crab mortality (binomial) data from a tethering experiment in summer 2017 in Back Sound, North Carolina.&lt;/p&gt; Methods and Sampling: For Table and Figure references below, see the document &quot;PredationAssay_statistical_analysis.pdf&quot; in the Supplemental Files section. Study Site Selection We conducted our study across eight discrete seagrass meadows (hereafter referred to as landscapes) located in Back Sound, North Carolina (NC), USA (3442′ N to 3439′ N, 7637′ W to 7631′ W) (Fig. S1). All of our sampled landscapes were composed of a mixture of Back Sound's dominant seagrasses: eelgrass and shoal grass, Halodule wrightii (Ascherson 1868) (Yeager et al. 2016). Landscapes were chosen based upon available aerial imagery in Google Earth Pro as of February 19, 2017, and ground-truthed for changes in seasonal seagrass growth/senescence using summer, 2017, drone photography and ImageJ 1.x (Schneider et al. 2012). No discernable differences in landscape fragmentation states (e.g. total area, number of patches) were found between the two aerial imagery sources. All landscapes were relatively shallow (1-1.5 m depth at high tide), reasonably isolated from other seagrass beds (distance to nearest seagrass meadow = 112 17 m [mean standard error]) and were appropriately sized to encompass short-term (e.g., daily, monthly) movements of common seagrass-associated fauna in this system (Yeager et al. 2016). We identified similarly sized landscapes (25882 6592 m2) available in Back Sound by defining the minimum convex polygon surrounding the seagrass meadow, regardless of the total seagrass cover within the polygon. Among eight candidate landscapes of similar size, we defined four continuous landscapes and four fragmented landscapes based on the number of patches, the perimeter-to-area ratio, and the largest patch's percent cover of the total seagrass area (Table 1). Seagrass fragmentation is often naturally coupled with habitat loss (Wilcove et al. 1986), resulting in the mean seagrass area of our fragmented landscapes being nearly half that of our continuous landscapes (Table 1). Thus, our experiment was designed to examine the effects of fragmentation (i.e., the breaking apart of habitat concomitant with habitat loss) rather than fragmentation per se (i.e., the breaking apart of habitat without habitat loss; sensu Fahrig 2003). Predation Assays Relative predation (i.e., mortality) was measured using tethered juvenile blue crabs (Callinectes sapidus Rathbun) of carapace widths 10-40 mm. Tethering is commonly used to measure relative predation on juvenile blue crabs (Wilson et al. 1990; Hovel and Lipcius 2001). We note that tethering cannot be used to determine absolute predation rates, as tethered prey have restricted flee potential, generally raising the incidence of predation (Peterson and Black 1994). Still, when interpreted conservatively, tethering data can elucidate differences the relative directionality of environmental factors affecting prey survival (i.e., positive or negative effects). Juvenile blue crabs were chosen for tethering due to their economic and ecological importance to coastal regions (McCann et al. 2017) and because they have served as a model prey organism in several previous studies of related design (e.g., Hovel and Lipcius 2001, 2002; Mahoney et al. 2018). Crab predation assays were run from June to July as this was the period during which we could obtain sufficient numbers of appropriately sized crabs for our experiment. All juvenile blue crabs were captured in seine nets from Oyster Creek, NC (3449'19&quot;N, 7627'07&quot;W). Crabs were glued (active ingredient cyanoacrylate) to 30-cm segments of 12-lbs test monofilament. We chose to use 30-cm segments of monofilament for tethers to allow crabs to exhibit natural burrowing behavior (Hovel and Fonseca 2005), mitigating some tethering artifacts of prey visibility (Peterson and Black 1994). Tethered crabs were attached to 60-cm long, 0.5-cm diameter, fiberglass stakes with attached floats for easy relocation. Once tethered, crabs were held overnight as a check for attachment integrity, and then deployed across our landscapes on the following day. Twenty tethered crabs were deployed (stakes pushed completely into the sediment) in each continuous and fragmented landscape per predation assay date. Within each landscape, 10 tethered crabs were haphazardly placed within seagrass edges, defined as 30 cm (a tether length) from the seagrass-mudflat interface. The other 10 tethered crabs were haphazardly placed in seagrass interiors, defined as ≥1 m from the seagrass-mudflat interface. Only patches with a radius of 1 m or larger were used for tethers classified as 'interior'. However, patches with a radius of &lt;1 m were used for a portion of our 'edge' tethers. All tethers were placed at least 1 m apart. We returned to landscapes at 1 h and 24 h to check crab status (live, eaten). All missing crabs were presumed eaten, as no crabs escaped tethers during the 24-h holding period. After 24 h, any remaining live crabs were removed from tethers and released. Crab tethering cycles were repeated four times in 2017 (June 9, June 14, July 5, and July 13). On July 13, only half of the continuous and fragmented landscapes were included in tethering assays due to a lack of crab availability. A total of 550 tethered juvenile blue crabs were deployed during our trials (see Table S1 for full sampling schedule and assay sample sizes). Point measurements of water temperature (C) were taken in each landscape at the location and time of all tethering assays and faunal sampling using hand-held thermometers (Table S1). We chose temperature as our seasonality proxy (Fig. S2) because several other seasonally affected factors including faunal densities correlate with water temperature variability. Additionally, the measurement of temperature is easy, cheap, reliable, and comparable to previous studies. Tether materials: EcoStakes – tomato plant stakes Locktite glue 12-lbs test monofilament fishing line Pool noodles – cut into rounds for tether relocation floats Hand-held digital thermometer- LYNCH Waterproof thermometer 39240 Hand-held refractometer-VEE GEE STX-3 Salinity 0-100%o Hand-held Garmin GPSmap 78 Electronic calipers – INOX waterproof IP54 Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-1635950 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1635950 completed F. Joel Fodrie University of North Carolina at Chapel Hill 252-726-6841 Institute of Marine Sciences & Department of Marine Sciences 3431 Arendell Street Morehead City NC 28557 USA jfodrie@unc.edu pointOfContact asNeeded Dataset Version: 2 Unknown Date SiteID C_F lat lon AirTemp_C WaterTemp_C Salinity_PSU Depth_m HighTide LowTide TimeInFromHigh Tide Bobber_Num CW_mm Claw_Num E_I TimeIn TimeOut hr1 hr24 ISO_DateTime_UTC_In Notes INOX waterproof IP54 Hand-held Garmin GPSmap 78 VEE GEE STX-3 LYNCH Waterproof thermometer 39240 theme None, User defined date site description latitude longitude air temperature water temperature at measurement depth salinity depth_w time_local time_elapsed deployment number width count flag ISO_DateTime_UTC comments featureType BCO-DMO Standard Parameters calipers GPS receiver Refractometer Thermometer instrument BCO-DMO Standard Instruments otherRestrictions otherRestrictions Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use. Collaborative Research: Habitat fragmentation effects on fish diversity at landscape scales: experimental tests of multiple mechanisms https://osprey.bco-dmo.org/project/714026 Collaborative Research: Habitat fragmentation effects on fish diversity at landscape scales: experimental tests of multiple mechanisms <p>Amount and quality of habitat is thought to be of fundamental importance to maintaining coastal marine ecosystems. This research will use large-scale field experiments to help understand how and why fish populations respond to fragmentation of seagrass habitats. The question is complex because increased fragmentation in seagrass beds decreases the amount and also the configuration of the habitat (one patch splits into many, patches become further apart, the amount of edge increases, etc). Previous work by the investigators in natural seagrass meadows provided evidence that fragmentation interacts with amount of habitat to influence the community dynamics of fishes in coastal marine landscapes. Specifically, fragmentation had no effect when the habitat was large, but had a negative effect when habitat was smaller. In this study, the investigators will build artificial seagrass habitat to use in a series of manipulative field experiments at an ambitious scale. The results will provide new, more specific information about how coastal fish community dynamics are affected by changes in overall amount and fragmentation of seagrass habitat, in concert with factors such as disturbance, larval dispersal, and wave energy. The project will support two early-career investigators, inform habitat conservation strategies for coastal management, and provide training opportunities for graduate and undergraduate students. The investigators plan to target students from underrepresented groups for the research opportunities.</p> <p>Building on previous research in seagrass environments, this research will conduct a series of field experiments approach at novel, yet relevant scales, to test how habitat area and fragmentation affect fish diversity and productivity. Specifically, 15 by 15-m seagrass beds will be created using artificial seagrass units (ASUs) that control for within-patch-level (~1-10 m2) factors such as shoot density and length. The investigators will employ ASUs to manipulate total habitat area and the degree of fragmentation within seagrass beds in a temperate estuary in North Carolina. In year one, response of the fishes that colonize these landscapes will be measured as abundance, biomass, community structure, as well as taxonomic and functional diversity. Targeted ASU removals will then follow to determine species-specific responses to habitat disturbance. In year two, the landscape array and sampling regime will be doubled, and half of the landscapes will be seeded with post-larval fish of low dispersal ability to test whether pre- or post-recruitment processes drive landscape-scale patterns. In year three, the role of wave exposure (a natural driver of seagrass fragmentation) in mediating fish community response to landscape configuration will be tested by deploying ASU meadows across low and high energy environments.</p> Habitat Fragmentation largerWorkCitation project eng; USA oceans -76.587826 -76.526267 34.651056 34.703251 2017-06-09 2017-07-13 North Carolina 0 BCO-DMO catalogue of parameters from Relative crab mortality (binomial) data from a tethering experiment in summer 2017 in Back Sound, North Carolina Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact http://lod.bco-dmo.org/id/dataset-parameter/781050.rdf Name: Date Units: unitless Description: <p>Date tethered crab deployed in ISO 8601 format yyyy-mm-dd</p> http://lod.bco-dmo.org/id/dataset-parameter/781051.rdf Name: SiteID Units: unitless Description: <p>Name of seagrass bed in which tether was deployed</p> http://lod.bco-dmo.org/id/dataset-parameter/781052.rdf Name: C_F Units: unitless Description: <p>Fragmentation state of seagrass bed: C = Continuous, F = Fragmented</p> http://lod.bco-dmo.org/id/dataset-parameter/781053.rdf Name: lat Units: decimal degrees Description: <p>Latitude</p> http://lod.bco-dmo.org/id/dataset-parameter/781054.rdf Name: lon Units: decimal degrees Description: <p>Longitude</p> http://lod.bco-dmo.org/id/dataset-parameter/781055.rdf Name: AirTemp_C Units: degrees Celsius (C) Description: <p>Air temperature at time and place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781056.rdf Name: WaterTemp_C Units: degrees Celsius (C) Description: <p>Water temperature at time and place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781057.rdf Name: Salinity_PSU Units: Practical Salinity Units (PSU) Description: <p>Salinity of water at time and place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781058.rdf Name: Depth_m Units: meters (m) Description: <p>Depth of water at time and place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781059.rdf Name: HighTide Units: unitless Description: <p>Time of high tide at place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781060.rdf Name: LowTide Units: unitless Description: <p>Time of low tide at place of tether deployment</p> http://lod.bco-dmo.org/id/dataset-parameter/781061.rdf Name: TimeInFromHigh Units: unitless Description: <p>At time of tether deployment, time passed since high tide</p> http://lod.bco-dmo.org/id/dataset-parameter/781062.rdf Name: Tide Units: unitless Description: <p>At time of tether deployment, ebb or flow tide</p> http://lod.bco-dmo.org/id/dataset-parameter/781063.rdf Name: Bobber_Num Units: per individual Description: <p>Individual ID number of tether (numbers may be repeated across dates)</p> http://lod.bco-dmo.org/id/dataset-parameter/781064.rdf Name: CW_mm Units: millimeters (mm) Description: <p>Carapace width (measured from spine to spine of crab)</p> http://lod.bco-dmo.org/id/dataset-parameter/781065.rdf Name: Claw_Num Units: per individual claw Description: <p>Number of claws the crab had intact at time of tethering</p> http://lod.bco-dmo.org/id/dataset-parameter/781066.rdf Name: E_I Units: unitless Description: <p>Position of tether deployment with seagrass bed; E = edge (≤0.3 m from seagrass/mudflat interface), I = Interior (&gt;1 m from seagrass/mudflat interface)</p> http://lod.bco-dmo.org/id/dataset-parameter/781067.rdf Name: TimeIn Units: unitless Description: <p>Local time of tether deployment [EDT][GMT-4h] in format h:mm</p> http://lod.bco-dmo.org/id/dataset-parameter/781068.rdf Name: TimeOut Units: unitless Description: <p>Local time of tether removal [EDT][GMT-4h] in format h:mm</p> http://lod.bco-dmo.org/id/dataset-parameter/781069.rdf Name: hr1 Units: unitless Description: <p>Status of crab on tether at 1 hour from deployment time; 1 = live/present, 0 = dead/missing</p> http://lod.bco-dmo.org/id/dataset-parameter/781070.rdf Name: hr24 Units: unitless Description: <p>Status of crab on tether at 24 hours from deployment time; 1 = live/present, 0 = dead/missing</p> http://lod.bco-dmo.org/id/dataset-parameter/781071.rdf Name: ISO_DateTime_UTC_In Units: unitless Description: <p>Date Time (UTC) in ISO 8601 format yyyy-mm-ddTHH:MMZ</p> http://lod.bco-dmo.org/id/dataset-parameter/781072.rdf Name: Notes Units: unitless Description: <p>Notes relevant to individual tether</p> GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact 7389 https://darchive.mblwhoilibrary.org/bitstream/1912/24821/1/dataset-780043_blue-crab-tethering-predation-assay__v1.tsv download 73415 https://darchive.mblwhoilibrary.org/bitstream/1912/25363/1/dataset-780043_blue-crab-tethering-predation-assay__v2.tsv download https://doi.org/10.1575/1912/bco-dmo.780043.2 download onLine dataset For Table and Figure references below, see the document &quot;PredationAssay_statistical_analysis.pdf&quot; in the Supplemental Files section. Study Site Selection We conducted our study across eight discrete seagrass meadows (hereafter referred to as landscapes) located in Back Sound, North Carolina (NC), USA (3442′ N to 3439′ N, 7637′ W to 7631′ W) (Fig. S1). All of our sampled landscapes were composed of a mixture of Back Sound's dominant seagrasses: eelgrass and shoal grass, Halodule wrightii (Ascherson 1868) (Yeager et al. 2016). Landscapes were chosen based upon available aerial imagery in Google Earth Pro as of February 19, 2017, and ground-truthed for changes in seasonal seagrass growth/senescence using summer, 2017, drone photography and ImageJ 1.x (Schneider et al. 2012). No discernable differences in landscape fragmentation states (e.g. total area, number of patches) were found between the two aerial imagery sources. All landscapes were relatively shallow (1-1.5 m depth at high tide), reasonably isolated from other seagrass beds (distance to nearest seagrass meadow = 112 17 m [mean standard error]) and were appropriately sized to encompass short-term (e.g., daily, monthly) movements of common seagrass-associated fauna in this system (Yeager et al. 2016). We identified similarly sized landscapes (25882 6592 m2) available in Back Sound by defining the minimum convex polygon surrounding the seagrass meadow, regardless of the total seagrass cover within the polygon. Among eight candidate landscapes of similar size, we defined four continuous landscapes and four fragmented landscapes based on the number of patches, the perimeter-to-area ratio, and the largest patch's percent cover of the total seagrass area (Table 1). Seagrass fragmentation is often naturally coupled with habitat loss (Wilcove et al. 1986), resulting in the mean seagrass area of our fragmented landscapes being nearly half that of our continuous landscapes (Table 1). Thus, our experiment was designed to examine the effects of fragmentation (i.e., the breaking apart of habitat concomitant with habitat loss) rather than fragmentation per se (i.e., the breaking apart of habitat without habitat loss; sensu Fahrig 2003). Predation Assays Relative predation (i.e., mortality) was measured using tethered juvenile blue crabs (Callinectes sapidus Rathbun) of carapace widths 10-40 mm. Tethering is commonly used to measure relative predation on juvenile blue crabs (Wilson et al. 1990; Hovel and Lipcius 2001). We note that tethering cannot be used to determine absolute predation rates, as tethered prey have restricted flee potential, generally raising the incidence of predation (Peterson and Black 1994). Still, when interpreted conservatively, tethering data can elucidate differences the relative directionality of environmental factors affecting prey survival (i.e., positive or negative effects). Juvenile blue crabs were chosen for tethering due to their economic and ecological importance to coastal regions (McCann et al. 2017) and because they have served as a model prey organism in several previous studies of related design (e.g., Hovel and Lipcius 2001, 2002; Mahoney et al. 2018). Crab predation assays were run from June to July as this was the period during which we could obtain sufficient numbers of appropriately sized crabs for our experiment. All juvenile blue crabs were captured in seine nets from Oyster Creek, NC (3449'19&quot;N, 7627'07&quot;W). Crabs were glued (active ingredient cyanoacrylate) to 30-cm segments of 12-lbs test monofilament. We chose to use 30-cm segments of monofilament for tethers to allow crabs to exhibit natural burrowing behavior (Hovel and Fonseca 2005), mitigating some tethering artifacts of prey visibility (Peterson and Black 1994). Tethered crabs were attached to 60-cm long, 0.5-cm diameter, fiberglass stakes with attached floats for easy relocation. Once tethered, crabs were held overnight as a check for attachment integrity, and then deployed across our landscapes on the following day. Twenty tethered crabs were deployed (stakes pushed completely into the sediment) in each continuous and fragmented landscape per predation assay date. Within each landscape, 10 tethered crabs were haphazardly placed within seagrass edges, defined as 30 cm (a tether length) from the seagrass-mudflat interface. The other 10 tethered crabs were haphazardly placed in seagrass interiors, defined as ≥1 m from the seagrass-mudflat interface. Only patches with a radius of 1 m or larger were used for tethers classified as 'interior'. However, patches with a radius of &lt;1 m were used for a portion of our 'edge' tethers. All tethers were placed at least 1 m apart. We returned to landscapes at 1 h and 24 h to check crab status (live, eaten). All missing crabs were presumed eaten, as no crabs escaped tethers during the 24-h holding period. After 24 h, any remaining live crabs were removed from tethers and released. Crab tethering cycles were repeated four times in 2017 (June 9, June 14, July 5, and July 13). On July 13, only half of the continuous and fragmented landscapes were included in tethering assays due to a lack of crab availability. A total of 550 tethered juvenile blue crabs were deployed during our trials (see Table S1 for full sampling schedule and assay sample sizes). Point measurements of water temperature (C) were taken in each landscape at the location and time of all tethering assays and faunal sampling using hand-held thermometers (Table S1). We chose temperature as our seasonality proxy (Fig. S2) because several other seasonally affected factors including faunal densities correlate with water temperature variability. Additionally, the measurement of temperature is easy, cheap, reliable, and comparable to previous studies. Tether materials: EcoStakes – tomato plant stakes Locktite glue 12-lbs test monofilament fishing line Pool noodles – cut into rounds for tether relocation floats Hand-held digital thermometer- LYNCH Waterproof thermometer 39240 Hand-held refractometer-VEE GEE STX-3 Salinity 0-100%o Hand-held Garmin GPSmap 78 Electronic calipers – INOX waterproof IP54 Specified by the Principal Investigator(s) Data processing: All data were entered electronically into an Excel spreadsheet. BCO-DMO Data Manager Processing Notes: * exported submitted excel file to csv format * added a conventional header with dataset name, PI name, version date * modified parameter names to conform with BCO-DMO naming conventions * date format converted to ISO 8601 standard format yyyy-mm-dd * cells with just a period as a value replaced will no-data values. No-data values in this dataset are displayed as the missing data identifier &quot;nd&quot; for &quot;no data&quot; in the BCO-DMO system. * added ISO_DateTime_ISO_In from local date and time in columns. * commas in comments replaced with semicolons to support csv output * data version 2 created. No change to data values, version 2 was created to fix an error in serving the &quot;Notes&quot; column which contains commas. The archived data version 1 of this dataset does not contain the full data due to this error. Specified by the Principal Investigator(s) asNeeded 7.x-1.1 Biological and Chemical Oceanography Data Management Office (BCO-DMO) Unavailable 508-289-2009 WHOI MS#36 Woods Hole MA 02543 USA info@bco-dmo.org http://www.bco-dmo.org Monday - Friday 8:00am - 5:00pm For questions regarding this resource, please contact BCO-DMO via the email address provided. pointOfContact INOX waterproof IP54 INOX waterproof IP54 PI Supplied Instrument Name: INOX waterproof IP54 PI Supplied Instrument Description:Electronic calipers – INOX waterproof IP54 Instrument Name: calipers Instrument Short Name: Instrument Description: A caliper (or "pair of calipers") is a device used to measure the distance between two opposite sides of an object. Many types of calipers permit reading out a measurement on a ruled scale, a dial, or a digital display. Hand-held Garmin GPSmap 78 Hand-held Garmin GPSmap 78 PI Supplied Instrument Name: Hand-held Garmin GPSmap 78 Instrument Name: GPS receiver Instrument Short Name: Instrument Description: Acquires satellite signals and tracks your location. This term has been deprecated. Use instead: https://www.bco-dmo.org/instrument/560 VEE GEE STX-3 VEE GEE STX-3 PI Supplied Instrument Name: VEE GEE STX-3 PI Supplied Instrument Description:Hand-held refractometer-VEE GEE STX-3 Salinity 0-100%o Instrument Name: Refractometer Instrument Short Name:Refractometer Instrument Description: A refractometer is a laboratory or field device for the measurement of an index of refraction (refractometry). The index of refraction is calculated from Snell's law and can be calculated from the composition of the material using the Gladstone-Dale relation. In optics the refractive index (or index of refraction) n of a substance (optical medium) is a dimensionless number that describes how light, or any other radiation, propagates through that medium. LYNCH Waterproof thermometer 39240 LYNCH Waterproof thermometer 39240 PI Supplied Instrument Name: LYNCH Waterproof thermometer 39240 PI Supplied Instrument Description:Hand-held digital thermometer- LYNCH Waterproof thermometer 39240 Instrument Name: Thermometer Instrument Short Name: Instrument Description: A device designed to measure temperature.