limnets English utf8 dataset McMurdo Dry Valleys LTER http://mcmlter.org/ 2014-11-04 ISO 19115-2 Geographic Information - North American Profile Metadata - Data with Biological Extensions ISO 19115-2:2009(E) Community Respiration Rates : Quantifying the Activity of the Electron Transport System (ETS) 2014-11-04 publication 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 monitoring of spatial and temporal patterns, and processes that control net primary production (carbon dynamics) in perennial ice-covered lakes. One of the primary losses of carbon fixed by phytoplankton is through respiration, directly by the phytoplankton themselves and secondarily through the metabolic contributions of heterotrophic organisms such as bacterioplankton and protozoa. The coupling of low metabolic activity and supersaturated gases in the water column prohibits a direct measurement of respiration. Therefore, we measure the respiratory electron transport system (ETS) activity which drives oxidative phosphorylation, and hence oxygen consumption in all aerobic organisms (Packard 1985). This data set addresses this core area of research and estimates a community-wide respiration rate at specific depths in McMurdo Dry Valley lakes (Hoare, Fryxell and Bonney). Name: Inigo San Gil Role: data manager completed McMurdo Dry Valleys LTER http://mcmlter.org/ unknown In 2016, metadata was enhanced and completed for data preservation and export (San Gil) 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, which are stored in the /data1/data/lakes/lakebio/ directory on INSTAAR's Unix system. The 1993/94 and 1994/95 datasets are Microsoft Excel version 6.0 files, and the1995/96, 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 Metaets9697.rtf and Metaets9798.rtf files. The files were called up using Microsoft Word version 6.0. Text from these files was used to create this page in html format. 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 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 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 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 ground condition 1993-10-31 2001-12-30 Energy of activation is an average of values ranging from 9300-16000 cal mol-1 (Ahmed and Kenner, 1977), and is supported by an experimentally derived value of 9720 cal mol-1 in Lake Bonney (Priscu, unpublished). If the absorbance of the kill sample is greater than the average of the live samples, ETS is reported as zero.   Citations    Ahmed, S. I., and R. A. Kenner. 1977. A study of in vitro electron transport activity in marine phytoplankton as a functio n of temperature.  Journal of Phycology 13: 116-121.              Christiansen, J.P., T.G. Owens, A.H. Devol, and T. Packard. 1980. Respiration physiological state in marine bacteria. Mari ne Biology 55: 267-276.              Kenner, R. A., and S. I. Ahmed. 1975. Measurements of electron transport activities in marine environments. Marine Biology  33: 119-127.              Packard, T.T. 1985. Measurement of electron transport activity in microplankton. Advances in Aquatic Microbiology 3: 207-2 61.              Priscu, J.C., and C.R. Goldman. 1984. The effect of temperature on photosynthetic and respiratory electron transport syste m activity in the shallow and deep-living phytoplankton of a subalpine lake. Freshwater Biology 14:143-155.     https://mcm.lternet.edu/sites/default/files/LIMNO_RESPIRATION_ETS.csv LIMNO_RESPIRATION_ETS eng; US McMurdo Dry Valleys LTER LIMNO_RESPIRATION_ETS Record Delimiter : \n Number of Header Lines : 28 Number of Footer Lines : 1 Orientation : Column Quote Character : "Field Delimiter : , false DATASET_CODE Code to ID the data table 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 ice from which sample was drawn ETS (umol O2/L*hr) Community Respiration Rate quantified by the Electron Transport System ETS COMMENTS Helpful hints about the sample RESPIRATION (umol O2/L*hr) Community Respiration Rate quantified by the Electron Transport System RESPIRATION COMMENTS Helpful hints about the 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/LIMNO_RESPIRATION_ETS.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 (2-light and 1-amber), two-500 mL amber Nalgene bottles, three-150 mL borosilicate glass bottles, two-20 mL scintillation vials, and one-30 mL serum vial. The two-one liter clear Nalgene bottles were used for the ETS experiment. Depending on the lake and depth at which each analysis was performed, 1000-2000 mL of lake water was filtered through a Whatman 47 mm GF/F filter. The filter was folded in half (organic material inside), placed in a glassine envelope, and stored at 0 degrees Celsius until analysis (<30 min). In an ice bath, the filter was combined with 3 mL of homogenization buffer and homogenized for 90 seconds with a glass/teflon tissue grinder. The mixture was decanted into a cone centrifuge tube; it was centrifuged in the cold for 3 minutes, vortexed for 30 seconds, and centrifuged for another 15 minutes. 0.5 mL of the extract was pipetted supernatant into three 1-cm quartz cuvettes (2 replicate, 1 control) and placed in an ice bath. The control sample was boiled for 10 minutes and cooled in an ice bath. 1.5 mL of substrate solution and 0.5 mL of INT solution was added to each cuvette, vortexed for 30 seconds, and incubated at 1-4C for one hour. The reaction was terminated in the cuvette with 0.5 mL of termination solution. The absorbance was measured at 490 nm with a spectrophotometer. Light absorption by the sample idirectly proportional to the moles of electrons transferred through the electron transport system (ETS). Community ETS (umol O2 L-1 hr-1) was calculated using the following equation: ETS = (AbsR - AbsC) a * b c * t where AbsR is the average absorbance of the replicate samples, AbsC is the absorbance of the control sample, a is ratio of the volume of homogenization buffer to the volume of lake water filtered, b is the ratio of the final volume of reaction mixture in each cuvette to the volume of extract supernatant, c is the extinction coefficient for formazan (31.8 Abs cm-1 umol O2-1), and t is the incubation period. Community ETS was adjusted to ambient lake temperature using the Arrhenius equation: ETSadj = ETS * e^(Ea (( 1 / (CI + 273 K)) - ( 1 / (CA + 273 K))) / R ) where Ea is the energy of activation (15,000 cal mol-1, Q10 = 2.66), CI is the incubation temperature (C), CA is the ambient lake water temperature at specific depth, and R is a gas constant (1.987 cal mol-1 K-1). A first order relationship exists between ETS activity and respiratory capacity in aquatic microorganisms (e.g., Kenner and Ahmed 1975, Christiansen et al. 1980). Our studies have revealed that 44% and 56% of measured ETS activity is from bacterioplankton and phytoplankton, respectively, in Lake Bonney (Takacs and Priscu, unpublished data). Using these relationships, in concert with published respiration:ETS ratios (Packard 1985), we derived a community respiration:ETS ratio of 0.61 for the water column of Lake Bonney. Individual respiration:ETS ratios for bacteria and phytoplankton were computed as 0.513 and 0.097, respectively. Metadata Access Constraints: none Metadata Use Constraints: none annually McMurdo Dry Valleys LTER http://mcmlter.org/ pointOfContact