Ian Hawes 2014-11-04 Chlorophyll-A Concentrations in Lake Hoare Benthic Mats 1996-97 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/d3e9d47d479379d6b9c30b8ecaf48968 https://mcm.lternet.edu/content/chlorophyll-concentrations-lake-hoare-benthic-mats-1996-97 As part of the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, the growth of benthic cyanobacteria-dominated mats in the lakes have been monitored. This dataset shows chlorophyll-a levels associated with the benthic mats. Values are provided for various depths of Lake Hoare during the 1996-97 field season, both with and without correction for phaeopigments. The data were obtained by Dr. Ian Hawes of the National Institute of Water and Atmospheric Research, Christchurch New Zealand (i.hawes@niwa.dri.nz), who should be contacted with any queries. The research was funded by the New Zealand Foundation for Research, Science and Technology, under grant CO1601. Logistic support was provided by the Taylor Valley Long Term Ecological Research Program. 1996-12-01 1996-12-31 ground condition Metadata completed in 2016Data and metadata migrated into the Drupal Ecological Information Management System in 2014. (San Gil) As needed Lake Hoare occupies a narrower portion of the Taylor Valley, dammed by the Canada Glacier. It would drain almost completely without this dam. There are a number of islands which may be related to an old terminal of Canada Glacier. The lake is fed primarily from direct runoff from the glacier, as well as meltwater streams. (Lake level rose ~1.5 m between 1972 and 1996). There are no surface outflows; the only known water loss is through ice ablation (evaporation, sublimation and physical scouring). Valley: Taylor Distance to Sea : 15 Maximum Length (km): 4.2 Maximum Width (km): 1 Maximum Depth (m): 34 Surface Area (km^2): 1.94 Ice Thickness Average Surface (m): 3.1 - 5.5 Volume (m^3 * 10^6): 17.5 162.935836791992 162.784423828125 -77.623085021973 -77.639259338379 73m 73m meter LTER Core Areas organic matter None <cntorg>McMurdo Dry Valleys LTER</cntorg> <onlink>http://mcmlter.org/</onlink> <span property="dc:title" content="McMurdo Dry Valleys LTER" class="rdf-meta element-hidden"></span> Name: Inigo San Gil Role: data manager Not Applicable Not Applicable Field and/or Lab Methods These data are based on analysis of replicated 1.98 cm2 cores of the pigmented surface layer of benthic microbial mats from Lake Hoare. Parallel experiments in which thicker cores were sectioned showed that this surface layer contained all chlorophyll-a present in the cores. They are expressed per unit area of core, units andmicro;g/cm2 (micrograms per square centimeter). All depths refer to depth from the surface and are in meters. Samples were obtained from an approximately linear transect stretching from the Lake Hoare laboratory complex towards the lake deepspot. Cores were collected through December 1996 by scuba divers. Initially, cores of 7 cm diameter were collected using sharpened perspex coring tubes. After retrieval to the surface, these were subsampled using sharpened, cut-off syringe barrels. Cores were stored at -20anddeg;C, in the dark, until processed in New Zealand some 2-3 months later. Extraction was into 10 ml of 90% acetone (allowing for volume of water in core), and was aided by grinding with a teflon pestle in a glass tube. Calculations were based on absorptance of the extract measured at 665, corrected by subtracting that at 750 nm. Correction for phaeopigments was accomplished by re-measuring absorptance after acidification with dilute HCl. Equations used for calculating chlorophyll-a in andmicro;m/cm2 with (Eq 1) and without (Eq 2) correction for phaeopigments were: Eq 1: (A665(na)-A665(ac)) x 27.3 x 1/vol x 1/area Eq 2: A665(na) x 11.23 x 1/vol x 1/area where A665(na) and A665(ac) are corrected absorptances (as optical density) before and after acidification, vol is volume of acetone used (ml) and area is the area of the core (cm2). These data are based on analysis of replicated 1.98 cm2 cores of the pigmented surface layer of benthic microbial mats from Lake Hoare. Parallel experiments in which thicker cores were sectioned showed that this surface layer contained all chlorophyll-a present in the cores. They are expressed per unit area of core, units andmicro;g/cm2 (micrograms per square centimeter). All depths refer to depth from the surface and are in meters. Samples were obtained from an approximately linear transect stretching from the Lake Hoare laboratory complex towards the lake deepspot. Cores were collected through December 1996 by scuba divers. Initially, cores of 7 cm diameter were collected using sharpened perspex coring tubes. After retrieval to the surface, these were subsampled using sharpened, cut-off syringe barrels. Cores were stored at -20anddeg;C, in the dark, until processed in New Zealand some 2-3 months later. Extraction was into 10 ml of 90% acetone (allowing for volume of water in core), and was aided by grinding with a teflon pestle in a glass tube. Calculations were based on absorptance of the extract measured at 665, corrected by subtracting that at 750 nm. Correction for phaeopigments was accomplished by re-measuring absorptance after acidification with dilute HCl. Equations used for calculating chlorophyll-a in andmicro;m/cm2 with (Eq 1) and without (Eq 2) correction for phaeopigments were: Eq 1: (A665(na)-A665(ac)) x 27.3 x 1/vol x 1/area Eq 2: A665(na) x 11.23 x 1/vol x 1/area where A665(na) and A665(ac) are corrected absorptances (as optical density) before and after acidification, vol is volume of acetone used (ml) and area is the area of the core (cm2). unknown bnthchla Columns descriptions, labels, parameter definitions, units. Location Name of lake where measurement was made The data provider Name of lake where measurement was made Season Season sampled The data provider Season sampled Depth (m) Depth at which sample was drawn from lake The data provider meter 1 Total chl-a (ug/cm2) Chlorophyll-a concentration The data provider micrograms/cm2 Avg chl-a (ug/cm2) Average Chlorophyll-a concentration The data provider micrograms/cm2 Chl-a corrected for phaeopigments (ug/cm2) Chl-a corrected for phaeopigments (ug/cm2) The data provider micrograms/cm2 Average Chl-a corrected for phaeopigments (ug/cm2) Average Chl-a corrected for phaeopigments (ug/cm2) The data provider micrograms/cm2 File Name Original file name before entered into database The data provider Original file name before entered into database McMurdo Dry Valleys LTER The data distributor shall not be liable for innacuracies in the content http 1 0 \n 1 column , https://mcm.lternet.edu/sites/default/files/bnthchla.csv None 2014-11-04 2014-11-04 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