limncn.dat English utf8 dataset McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact 2014-11-04 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Particulate organic carbon (POC) and nitrogen (PON) concentrations in discrete water column samples collected from lakes in the McMurdo Dry Valleys, Antarctica (1993-2024, ongoing) 2014-11-04 publication Cristina Takacs-Vesbach University of New Mexico https://www.unm.edu/ cvesbach@unm.edu http://www.vesbachlab.org pointOfContact John Priscu Montana State University http://www.montana.edu/ jpriscu@montana.edu pointOfContact documentDigital An important part of the McMurdo Long Term Ecological Research (LTER) is evaluating carbon and nitrogen budgets in perennial ice-covered lakes. This dataset addresses this core area of research and quantifies the particulate organic carbon (POC) and nitrogen (PON) found at specific depths in lakes across the McMurdo Dry Valleys of Antarctica. Name: Jade Lawrence Role: field technician Name: Renée F. Brown Role: data manager Name: Amy Chiuchiolo Role: former field crew Name: Kathleen A. Welch Role: former lab crew Name: Denise Steigerwald Role: former data manager Name: Chris Gardner Role: former data manager Name: Inigo San Gil Role: former data manager completed McMurdo Dry Valleys LTER Information Manager im@mcmlter.org pointOfContact unknown Data from this table was submitted to INSTAAR by John Priscu's team at Montana State University. The raw data files listed under 'file name' are the names of the original files submitted. The 1993/94 and 1994/95 datasets are Microsoft Excel version 6.0 files, and the 1995/96, 1996/97 and 1997/98 datasets are ascii text files. Upon arrival at INSTAAR, the data manager fine-tuned the location codes and limno runs to match those provided in the "locations, dates, codes for lake chemistry, biology samples" file. The file was imported into Microsoft Access on INSTAAR's Unix system, and can currently be found there. The file  was then exported in ascii, comma delimited text and MS-DOS text (table layout) to present on the MCM LTER web site. Both of these files are linked to this web page above. Information for the metadata was obtained from the Metachn9697.rtf file. The file was called up using  Microsoft Word version 6.0. Text from this file was used to create this page in html format.   Data for the 2005-6 and 2006-7 season was updated in Oct 2009   Metadata was standardized to EML in 2006, and enhanced in 2014 using the Drupal Ecological Information Management System   In 2020, issues regarding how filter blank corrections were applied to the particulate organic carbon data were identified. The errors applied to the carbon data from the 2003-04 through the 2009-10 austral summer field seasons. All data from this period were re-processed according to the equations in the MCM LTER limno methods manual, and these corrections were applied to this data package in April 2021.   organic matter theme LTER Core Areas English Lake Bonney is a saline lake with permanent ice cover at the western end of Taylor Valley in the McMurdo Dry Valleys of Victoria Land, Antarctica. It is 7 kilometres or 4.3 mi long and up to 900 metres or 3,000 ft wide. A narrow channel only 50 metres or 160 ft wide. Lake Bonney at Narrows separates the lake into East Lake Bonney 3.32 square kilometres or 1.28 sq mi and West Lake Bonney, 0.99 square kilometres or 0.38 sq mi. The west lobe is flanked by Taylor glacier. Valley: Taylor Distance to Sea : 25 Maximum Length (km): 4.8 Maximum Width (km): 0.9 Maximum Depth (m): 37 Surface Area (km^2): 3.32 Ice Thickness Average Surface (m): 3 - 4.5 Volume (m^3 * 10^6): 54.7 162.536209106445 162.353210449219 -77.724441528320 -77.697700500488 The Lake Fryxell basin is formed by a moraine depression in a wider portion of the Taylor Valley. It has a number of moraine islands and shallower areas, as well as several relatively well developed deltas. The lake is fed by at least 10 meltwater streams with a total drainage catchment of 230 km2. The lake is dammed to the southwest by the Canada Glacier and is topographically closed. It is perennially ice covered; during summer months, an ice-free moat generally forms around much of the lake margin. Lake levels have risen ~2 m between 1971 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 : 9 Maximum Length (km): 5.8 Maximum Width (km): 2.1 Maximum Depth (m): 20 Surface Area (km^2): 7.08 Ice Thickness Average Surface (m): 3.3 - 4.5 Volume (m^3 * 10^6): 25.2 163.259582519531 163.048782348633 -77.622711181641 -77.597076416016 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 -77.639259338379 -77.623085021973 Lake Joyce lies in the Pearse Valley against the Taylor Glacier.  Valley: Pearse  Distance to Sea : 44  Maximum Length (km): 1  Maximum Width (km): 1  Maximum Depth (m): 35  Surface Area (km^2): 0.83  Ice Thickness Average Surface (m): 3.9 - 5.6  Volume (m^3 * 10^6): 4.9 161.662445068359 161.608886718750 -77.726486206055 -77.715972900391 A lake with an area of 1 square mile which occupies the north portion of Pyramid Trough, Scott Coast. Named by New Zealand Geographic Board (NZGB) (1994) in association with Pyramid Trough. 162.823226928711 162.718856811523 -77.442016601563 -77.417655944824 Lake Miers lies in the Miers Valley. Valley: Miers Distance to Sea : 20 Maximum Length (km): 1.5 Maximum Width (km): 0.7 Maximum Depth (m): 21 Surface Area (km^2): 1.3 Ice Thickness Average Surface (m): 3.4 - 6 Volume (m^3 * 10^6): 2.9 163.886840820313 163.812332153320 -78.101478576660 -78.094047546387 Lake Vanda is located in the Wright Valley, adjacent to the Taylor Valley. It is fed primarily by the Onyx River, which has its origin at Lake Brownworth, and ultimately at the Lower Wright Glacier located ~27 km east of the lake. The lake has no outflow. Valley: Wright Distance to Sea : 47 Maximum Length (km): 8 Maximum Width (km): 2 Maximum Depth (m): 75 Surface Area (km^2): 5.2 Ice Thickness Average Surface (m): 2.8 - 4.2 Volume (m^3 * 10^6): 160 161.691970825195 161.391906738281 -77.542304992676 -77.518882751465 Lake Bonney is a saline lake with permanent ice cover at the western end of Taylor Valley in the McMurdo Dry Valleys of Victoria Land, Antarctica. It is 7 kilometres or 4.3 mi long and up to 900 metres or 3,000 ft wide. A narrow channel only 50 metres or 160 ft wide. Lake Bonney at Narrows separates the lake into East Lake Bonney 3.32 square kilometres or 1.28 sq mi and West Lake Bonney, 0.99 square kilometres or 0.38 sq mi. Valley: Taylor Distance to Sea : 28 Maximum Length (km): 2.6 Maximum Width (km): 0.9 Maximum Depth (m): 40 Surface Area (km^2): 0.99 Ice Thickness Average Surface (m): 2.8-4.5 Volume (m^3 * 10^6): 10.1 162.354934692383 162.269104003906 -77.727287292480 -77.714805603027 ground condition 1993-10-27 2024-12-23 Funding for this work has been provided by several grants from the US National Science Foundation for Long Term Ecological Research, most recently under award #OPP-2224760. https://mcm.lternet.edu/sites/default/files/data/mcmlter-lake-poc_pon-20250928.csv LIMNO_POC_PON eng; US McMurdo Dry Valleys LTER LIMNO_POC_PON Record Delimiter : \n Number of Header Lines : 1 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Code to designate the table name LIMNO_RUN Code for lake's sampling location and date Location Name Name of lake where measurement was made Location Code Code for site where measurement was made DATE_TIME Date on which sample was gathered Date Time Format: mm/dd/yyyy Depth (m) Distance below the piezometric water level from which sample was drawn. POC (ug/L) Particulate organic carbon concentration found at lake depth POC (microM) Particulate organic carbon concentration found at lake depth POC Comments Helpful hints about the POC sample PON (ug/L) Particulate organic nitrogen concentration found at lake depth PON (microM) Particulate organic nitrogen concentration found at lake depth PON Comments Helpful hints about the PON sample C:N Carbon to Nitrogen Ratio Sample Comments Helpful hints about the overall sample File Name Name of file in which data was submitted DEPTH MASL Depth referred to the Sea level. Distance below Mean Average Sea water level reference from which sample was drawn DBF https://mcm.lternet.edu/sites/default/files/data/mcmlter-lake-poc_pon-20250928.csv dataset Lake water samples were collected at specific depths with a five-liter Niskin bottle during normal LTER limnological sampling. Sub-samples were decanted into three 1 L Nalgene bottles (two light and one amber), two 500 mL amber Nalgene bottles, three 150 mL borosilicate glass bottles, two 20 mL scintillation vials, and one 30 mL serum vial. A 500 mL sample from the one liter amber Nalgene bottle was decanted and filtered through a combusted Whatman 25 mm GF/F filter (475 °C for 4 hours). The filter was placed onto an aluminum weighing pan and air dried. Once the filters were dry, the pans were stacked together and frozen for later analysis.  Filters were acidified with HCL fumes, and analyzed using an Elemental Analyzer (currently a CE Elantech Flash EA 1112 Elemental Analyzer). Total particulate organic carbon (POC) and particulate organic nitrogen (PON) was obtained by comparison with an acetanilide standard curve. Prior to the 0304 season, analysis was done on a 10 mm diameter sub-sample punch of the GF/F filter; from 0304 to present, the entire GF/F filter was analyzed. See the maintenance section for further details regarding data from 2003-04 thru the 2019-20 field seasons. Instrument detection limits for POC and PON are 10 μg punch-1 and 5 μg punch-1 respectively. Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact