Sarah N. PowerMark R. SalvatoreEric R. SokolLee F. StanishJohn "Jeb" E. Barrett 2020-09-09 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/9acbbde9abc1e013f8c9fd9c383327f4 https://mcm.lternet.edu/content/microbial-mat-biomass-and-normalized-difference-vegetation-index-ndvi-values-lake-fryxell This package contains data collected from microbial mat surveys (i.e., percent cover, ash-free dry mass (AFDM), and pigment concentrations – chlorophyll-a, scytonemin, and carotenoids) associated with satellite-derived Normalized Difference Vegetation Index (NDVI) values from the Lake Fryxell Basin of Taylor Valley, located in the McMurdo Dry Valleys of Antarctica. The purpose of this study was to quantitatively compare key microbial mat characteristics to NDVI. Data were collected at seven plot locations within the Canada Glacier Antarctic Specially Protected Area (ASPA) near Canada Stream, as well as alongside Green Creek and McKnight Creek. NDVI values were derived from a WorldView-2 multispectral satellite image taken of the Lake Fryxell Basin on January 19, 2018, while biological ground surveying and sampling were conducted during the 2nd and 4th weeks of January 2018.    2018-01-09 2018-01-25 ground condition As needed Coordinates taken from 1996-97 GPS measurements at center of creek where it enters Lake Fryxell Parent Stream: Canada Stream Provenance : GPS96-97.DOC ID: canada_mouth 163.074447600000 163.074447600000 -77.614922000000 -77.614922000000 18m 18m meter Green Creek at mouth Description: Coordinates taken from 1996-97 GPS measurements at center of creek where it enters Lake Fryxell ID: green_mouth File Name :GPS96-97.DOC 163.063507080078 163.063507080078 -77.622589111328 -77.622589111328 19m 19m meter McKnight Creek at mouth ID: mcknight_mouth 163.264724700000 163.264724700000 -77.599724000000 -77.599724000000 LTER Core Areas primary production None <cntperp> <cntper>McMurdo Dry Valleys LTER Information Manager</cntper> </cntperp> <cntemail>im@mcmlter.org</cntemail> Name: Renée F. Brown Role: data manager Not Applicable Not Applicable Field and/or Lab Methods Locations of visually conspicuous microbial mats outside of stream channels were selected for seven 100 m2 plots beside Canada Stream in the Canada Glacier Antarctic Specially Protected Area (ASPA), Green Creek, and McKnight Creek in the Lake Fryxell Basin. Plots Canada Stream-1, -2, -3, and -4 were all located in the lower flush of the ASPA and Canada Stream-5 was in the upper flush. Hemispherical photos of ground cover along with position data were taken every 5 m at each of the seven plots. Using a random stratified sampling design, we sampled microbial mat from 9 or 10 locations within each plot for pigment chemistry and ash-free dry mass (AFDM).The hemispherical photos were analyzed for microbial mat cover using ImageJ, an image analysis software. By converting the photos to binary black and white images, the software distinguished pixels representing microbial mats (black) from those representing bare soil or rocks (white). Estimates for percent cover were quantified using a histogram. Chlorophyll-a concentration was measured with a spectrophotometer (Shimadzu UV-1601) using a protocol that corrects for scytonemin concentration. The samples were dried at 105°C for 24 hrs and extracted in 10 mL of 90% unbuffered acetone using 0.5 g of mat, based on protocols from Garcia‐Pichel and Castenholz (1991) and standard methods employed by the McMurdo Dry Valleys Long Term Ecological Research program (MCM LTER). The samples were then left for 24 hrs in a dark room at ambient temperature for complete chlorophyll extraction. After centrifuging for 10 min at 4000 RPM, they were analyzed on a spectrophotometer using 10 mL cuvettes. The absorbances contributed by chlorophyll-a, carotenoids, and scytonemin were quantified at 663, 490, and 384 nm, respectively, using the trichromatic equations outlined in Garcia‐Pichel and Castenholz (1991). One sample from Canada Stream-2 had extremely high pigment concentrations overall, with values greater than 6 standard deviations of the mean chlorophyll-a concentrations for all observations, and it was removed from the dataset. AFDM was calculated by weighing approximately 0.25 g of oven-dried sample, combusting at 550°C for 60 min using a muffle furnace, and reweighing after cooling in a desiccator. Given the extremely low clay content of soils in this region, the rehydration of clays was assumed negligible, so the methods did not include rewetting samples to account for the hydration of clays.The WorldView-2 multispectral satellite (DigitalGlobe, Inc.) collected a cloud-free image of the Lake Fryxell Basin on January 19, 2018, within 10 days of our surveying and sampling. The image was georeferenced using ground control points and processed to atmospherically corrected surface reflectance using the Environment for Visualizing Images software (ENVI, Harris Geospatial). We calculated the normalized difference vegetation index (NDVI) for the image. Using ArcMap, we converted the NDVI image raster file to points and then selected the pixels whose centroids fell within the 100 m2 plot boundaries. Each plot corresponds to approximately 14-17 pixels (5.95 m2 per pixel) with unique NDVI values. Locations of visually conspicuous microbial mats outside of stream channels were selected for seven 100 m2 plots beside Canada Stream in the Canada Glacier Antarctic Specially Protected Area (ASPA), Green Creek, and McKnight Creek in the Lake Fryxell Basin. Plots Canada Stream-1, -2, -3, and -4 were all located in the lower flush of the ASPA and Canada Stream-5 was in the upper flush. Hemispherical photos of ground cover along with position data were taken every 5 m at each of the seven plots. Using a random stratified sampling design, we sampled microbial mat from 9 or 10 locations within each plot for pigment chemistry and ash-free dry mass (AFDM).The hemispherical photos were analyzed for microbial mat cover using ImageJ, an image analysis software. By converting the photos to binary black and white images, the software distinguished pixels representing microbial mats (black) from those representing bare soil or rocks (white). Estimates for percent cover were quantified using a histogram. Chlorophyll-a concentration was measured with a spectrophotometer (Shimadzu UV-1601) using a protocol that corrects for scytonemin concentration. The samples were dried at 105°C for 24 hrs and extracted in 10 mL of 90% unbuffered acetone using 0.5 g of mat, based on protocols from Garcia‐Pichel and Castenholz (1991) and standard methods employed by the McMurdo Dry Valleys Long Term Ecological Research program (MCM LTER). The samples were then left for 24 hrs in a dark room at ambient temperature for complete chlorophyll extraction. After centrifuging for 10 min at 4000 RPM, they were analyzed on a spectrophotometer using 10 mL cuvettes. The absorbances contributed by chlorophyll-a, carotenoids, and scytonemin were quantified at 663, 490, and 384 nm, respectively, using the trichromatic equations outlined in Garcia‐Pichel and Castenholz (1991). One sample from Canada Stream-2 had extremely high pigment concentrations overall, with values greater than 6 standard deviations of the mean chlorophyll-a concentrations for all observations, and it was removed from the dataset. AFDM was calculated by weighing approximately 0.25 g of oven-dried sample, combusting at 550°C for 60 min using a muffle furnace, and reweighing after cooling in a desiccator. Given the extremely low clay content of soils in this region, the rehydration of clays was assumed negligible, so the methods did not include rewetting samples to account for the hydration of clays.The WorldView-2 multispectral satellite (DigitalGlobe, Inc.) collected a cloud-free image of the Lake Fryxell Basin on January 19, 2018, within 10 days of our surveying and sampling. The image was georeferenced using ground control points and processed to atmospherically corrected surface reflectance using the Environment for Visualizing Images software (ENVI, Harris Geospatial). We calculated the normalized difference vegetation index (NDVI) for the image. Using ArcMap, we converted the NDVI image raster file to points and then selected the pixels whose centroids fell within the 100 m2 plot boundaries. Each plot corresponds to approximately 14-17 pixels (5.95 m2 per pixel) with unique NDVI values. unknown MMNDVI_CHEMISTRY Microbial mat survey chemistry Dataset code Internal dataset code. The data provider Internal dataset code. Plot name Plot location name where sample was collected. The data provider Plot location name where sample was collected. Replicate number Replicate number within the associated plot. The data provider Replicate number within the associated plot. Scytonemin concentration Scytonemin concentration, expressed in micrograms per gram of dry soil. The data provider microgramsPerGram Carotenoid concentration Carotenoid concentration, expressed in micrograms per gram of dry soil. The data provider microgramsPerGram Chlorophyll-a concentration Chlorophyll-a concentration, expressed in micrograms per gram of dry soil. The data provider microgramsPerGram Ash Free Dry Mass Ash-free dry mass content, expressed in milligrams per gram of dry soil. The data provider milligramsPerGram Comments Comments regarding NA values. The data provider Comments regarding NA values. McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 1 column , https://mcm.lternet.edu/sites/default/files/data/MMNDVI_CHEMISTRY.csv None MMNDVI_COVER Microbial mat survey percent cover Dataset code Internal dataset code. The data provider Internal dataset code. Plot name Plot location name where sample was collected. The data provider Plot location name where sample was collected. Percent cover Percent cover value. The data provider dimensionless McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 1 column , https://mcm.lternet.edu/sites/default/files/data/MMNDVI_COVER.csv None MMNDVI_NDVI NDVI values Dataset code Internal dataset code. The data provider Internal dataset code. Plot location Plot location name where sample was collected. The data provider Plot location name where sample was collected. Normalized Difference Vegetation Index Normalized Difference Vegetation Index (NDVI) values. The data provider dimensionless McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 1 column , https://mcm.lternet.edu/sites/default/files/data/MMNDVI_NDVI.csv None MMNDVI_LOCATIONS Plot locations Dataset code Internal dataset code. The data provider Internal dataset code. Plot location Plot location name where sample was collected. The data provider Plot location name where sample was collected. Latitude Latitude of plot location. The data provider decimalDegrees Longitude Longitude of plot location. The data provider decimalDegrees McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 1 column , https://mcm.lternet.edu/sites/default/files/data/MMNDVI_LOCATIONS.csv None 2020-09-09 2020-09-09 McMurdo Dry Valleys LTER http://mcmlter.org/ Biological Data Profile of the Content Standards for Digital Geospatial Metadata devised by the Federal Geographic Data Committee. Drupal Ecological information Management Systems, version D7, Biological Data Profile module