John C. Priscu 2023-12-13 tabular digitial data McMurdo Dry Valleys LTER McMurdo Dry Valleys LTER 10.6073/pasta/40739c7a47a51e28d811da012f1d6283 https://mcm.lternet.edu/content/particulate-phosphorus-concentrations-discrete-water-column-samples-collected-lakes-mcmurdo An key component of the McMurdo Dry Valleys Long Term Ecological Research (LTER) project involves the long-term monitoring of nutrient cycles. This data package contributes to this core area of research by quantifying particulate phosphorus concentrations found at specific depths in several perennially ice-covered lakes in the McMurdo Dry Valleys region of Antarctica. 2006-11-10 2019-12-17 ground condition As needed 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 -77.697700500488 -77.724441528320 57m 57m meter 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 -77.714805603027 -77.727287292480 57m 57m meter 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 -77.597076416016 -77.622711181641 18m 18m meter 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 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 -78.094047546387 -78.101478576660 240m 240m meter 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 -77.518882751465 -77.542304992676 143m 143m meter LTER Core Areas inorganic nutrients None <cntperp> <cntper>McMurdo Dry Valleys LTER Information Manager</cntper> </cntperp> <cntemail>im@mcmlter.org</cntemail> 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 Not Applicable Not Applicable Field and/or Lab Methods 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 and acidified Whatman 25 mm GF/F filter. The filters were pre-combusted at 475 °C for 4 hours to remove organic phosphorus, soaked in 1% HCl, rinsed with DI water, and then brought to pH 8 with sodium hydroxide before being dried and transported to the field. After filtering, 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. The filter analysis method of total particulate phosphorus in natural waters is based on the digestion procedure of Solórzano and Sharp (1980), and on a modification developed by Murphy and Riley (1962) and Strickland and Parsons (1972).  Residue collected on a filter is treated with magnesium sulfate and baked at high temperature to decompose organic phosphate.  The residue is then treated with hydrochloric acid to hydrolyze polyphosphates and the orthophosphate is measured by the Molybdate method. Analysis of orthophosphate depends on the reduction of a stable phosphomolybdate complex by ascorbic acid in the presence of antimony. A blue sol is produced; our standard curves showed linearity in absorbance up to 9.5 µM P (294 µg P L-1) using an Ocean Optics Jaz Spectrometer with a 10 cm cell at 885 nm wavelength. Solórzano and Sharp (1980) and Priscu (MCM LTER Limno Methods Manual, 2019) revealed that the method gives 100% recovery with refractory phosphorus compounds (apple leaf standard) in marine and fresh waters. All samples that were analyzed in 2021 (2012-2013 to 2019-2020 field seasons) were centrifuged at 5000 rpm for ten minutes after the addition of the mixed reagent. Our tests indicated that this centrifugation step reduced the absorbance of the blanks. Samples analyzed in previous years (2006-2007 to 2011-2012 field seasons) were centrifuged at 2000 rpm for five minutes to decrease turbidity if the sample looked cloudy. L2 samples from the 2007-2008 season were analyzed in Crary Laboratory in McMurdo Station with a different spectrophotometer and a modified protocol. These samples were diluted ten times before the addition of mixed reagent. The turbidity of each sample at 660 nm was evaluated on the spectrophotometer. If absorbance at 660 nm exceeded 0.002, the samples were syringe filtered before being analyzed at 885 nm. These samples were not centrifuged, and no filter blanks were subtracted from the sample absorbances. No particulate phosphorus data is available for the 2010/2011 field season. Particulate phosphorus is no longer collected or analyzed as of the 2022-2023 field season. Samples collected during the 2021-2022 and 2022-2023 austral summers have not been analyzed. These samples are in storage, but there is no plan to analyze those samples as of March 2025.  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 and acidified Whatman 25 mm GF/F filter. The filters were pre-combusted at 475 °C for 4 hours to remove organic phosphorus, soaked in 1% HCl, rinsed with DI water, and then brought to pH 8 with sodium hydroxide before being dried and transported to the field. After filtering, 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.The filter analysis method of total particulate phosphorus in natural waters is based on the digestion procedure of Solórzano and Sharp (1980), and on a modification developed by Murphy and Riley (1962) and Strickland and Parsons (1972).  Residue collected on a filter is treated with magnesium sulfate and baked at high temperature to decompose organic phosphate.  The residue is then treated with hydrochloric acid to hydrolyze polyphosphates and the orthophosphate is measured by the Molybdate method. Analysis of orthophosphate depends on the reduction of a stable phosphomolybdate complex by ascorbic acid in the presence of antimony. A blue sol is produced; our standard curves showed linearity in absorbance up to 9.5 µM P (294 µg P L-1) using an Ocean Optics Jaz Spectrometer with a 10 cm cell at 885 nm wavelength. Solórzano and Sharp (1980) and Priscu (MCM LTER Limno Methods Manual, 2019) revealed that the method gives 100% recovery with refractory phosphorus compounds (apple leaf standard) in marine and fresh waters.All samples that were analyzed in 2021 (2012-2013 to 2019-2020 field seasons) were centrifuged at 5000 rpm for ten minutes after the addition of the mixed reagent. Our tests indicated that this centrifugation step reduced the absorbance of the blanks. Samples analyzed in previous years (2006-2007 to 2011-2012 field seasons) were centrifuged at 2000 rpm for five minutes to decrease turbidity if the sample looked cloudy.L2 samples from the 2007-2008 season were analyzed in Crary Laboratory in McMurdo Station with a different spectrophotometer and a modified protocol. These samples were diluted ten times before the addition of mixed reagent. The turbidity of each sample at 660 nm was evaluated on the spectrophotometer. If absorbance at 660 nm exceeded 0.002, the samples were syringe filtered before being analyzed at 885 nm. These samples were not centrifuged, and no filter blanks were subtracted from the sample absorbances.No particulate phosphorus data is available for the 2010/2011 field season.Particulate phosphorus is no longer collected or analyzed as of the 2022-2023 field season. Samples collected during the 2021-2022 and 2022-2023 austral summers have not been analyzed. These samples are in storage, but there is no plan to analyze those samples as of March 2025.  unknown limno_pp Particulate phosphorus data. Dataset code Internal dataset code. The data provider Internal dataset code. Limno run Code for lake's sampling location and date. The data provider Code for lake's sampling location and date. Location name Name of lake where measurement was made. The data provider Name of lake where measurement was made. Location code Code for site where measurement was made. The data provider Code for site where measurement was made. Date Date on which sample was gathered. The data provider calendar date/time MM/DD/YYYY gregorian calendar Depth Distance below the piezometric water level from which sample was drawn. The data provider meter Particulate phosphorus Particulate phosphorus concentration in micromoles. The data provider micromole Particulate phosphorus Particulate phosphorus concentration in micrograms per liter. The data provider microgramPerLiter Remarks Remarks about the sample. The data provider Remarks about the sample. Filename Name of file in which data was submitted. The data provider Name of file in which data was submitted. MASL depth Depth corrected for meters above sea level. The data provider meter 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/mcmlter-lake-pp-20250402.csv None 2023-12-13 2023-12-13 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