uid=MCM,o=EDI,dc=edirepository,dc=org all public read cliatgrz.dat Johanna Laybourn-Parry

University Road, Clifton Bristol BS8 1SS Bristol - None - BS8 1S GB

jo.laybourn-parry@bristol.ac.uk McMurdo Dry Valleys LTER http://mcmlter.org/ Inigo San Gil

Department of Biology, MSC03 2020 University of New Mexico Albuquerque NM 87131 US

(505) 277-2625 (505) 277-2541 isangil@lternet.edu data manager 2014-11-10 English

In conjunction with the Long Term Ecological Research (LTER) project in the McMurdo Dry Valleys of Antarctica, lakes were monitored for microzooplankton by a team based out of the University of Nottingham (led by Johanna Laybourn-Parry). This dataset shows grazing rates of ciliates feeding on cryptophytes between November 1997 and January 1998. The sample for this micro dataset was gathered at the Lake Fryxell.

grazing lakes limnology zooplankton LTER Controlled Vocabulary Antarctica ciliate cryptophyte grazing ingestion lake limnology microzooplankton Station Keywords population dynamics LTER Core Areas

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https://mcm.lternet.edu/content/microzooplankton-ciliate-grazing-rates 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): 25.2 163.048782348633 163.259582519531 -77.597076416016 -77.622711181641 18 18 meter 1997-11-01 1998-01-01  Data for this file was submitted by Johanna Laybourn-Parry to the data manager at INSTAAR on October 21, 1998. Files were sent via e-mail as well as a hard copy. The original version of the file is stored on the Unix system in "/data1/data/lakes/plankton/laybourn-parry/DV". Upon arrival at INSTAAR, the data manager reformatted the file to present it in a relational mode. This was done using Microsoft Access. It was then exported in comma delimited ascii and MS-DOS text format to present on the web. Links to these files are provided above.   On 2006, metadata was standardized to the EML format.  in 2014, metadata was enhanceded with the Drupal Ecological information management system (Inigo San Gil).  Completed in 2016 McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER http://mcmlter.org/ McMurdo Dry Valleys LTER

Ciliate samples were collected from Lake Fryxell by drilling a hole through the thick ice cover (approximately 4m thick) above the deepest point of the lake. A 2.21 Niskin bottle was used to retrieve duplicate 500 ml water samples from a 9m depth. The water samples were fixed in Lugol's iodine and concentrated by settling, prior to counting in a Sedgewick-Rafter counting chamber under phase microscopy at x160. Cryptophyte biomass was calculated by measuring 50 cells on each preparation. Biovolume was derived by applying an ellipsoid geometric shape and converted to carbon using a conversion figure of 220fg C/microm3. Ciliate ingestion rates were determined using live cryptophytes. Ciliates were incubated in the dark at 2 degrees C until no autofluorescence from ingested cryptophytes was visible within the cells. Freshly collected cryptophytes were concentrated by gravity filtration. The ciliates were then incubated with two concentrations of cryptophytes, 8500/ml and 15000/ml. The former concentration is typical of the deep maximum of cryptophytes in Lake Fryxell, the latter is close to the highest level ever recorded in Lake Fryxell. Ingestion rates were measured at 6 intervals over an 8 hour period. Samples were fixed with ice-cold 2% glutaraldehyde (final concentration), filtered onto 10 microm polycarbonate filters and viewed under epifluorescence microscopy. Ingested cryptophytes were visible within the ciliates by their orange autofluorescence. Fifty ciliates were examined on each preparation.

cliatgrz cliatgrz.csv 332 1 0 \n column , " https://mcm.lternet.edu/sites/default/files/cliatgrz.csv LOCATION_NAME Location Name Name of lake where measurement was made (lake fryxell) string Name of lake where measurement was made (lake fryxell) BEGINNING_DATE Beginning Date Earliest date on which samples were taken date mm/dd/yyyy ENDING_DATE Ending Date Latest date on which samples were taken date mm/dd/yyyy Depth (m) Depth (m) Depth at which sample was drawn from lake meter 1 real 0 20 Type of Organism Type of Organism Category describing species string Category describing species Min ingest rate (cryp/cil/h) Min ingestion rate (cryptophytes/ciliate/h) Lowest rate at which cryptophytes were consumed #ofcryptophytes/ciliate/hour 0.01 real 0 Max ingest rate (cryp/cil/h) Max ingestion rate (cryptophytes/ciliate/h) Highest rate at which cryptophytes were consumed #ofcryptophytes/ciliate/hour 0.01 real 0 Min cryp mass rem/day (ug C/L) Min cryptophyte biomass removed daily (microg C / l) Lowest amount of cryptophyte biomass consumed in 24 hours microgofcarbon/liter 1 real 0 Null None given Max cryp mass rem/day (ug C/L) Max cryptophyte biomass removed daily (microg C / l) Highest amount of cryptophyte biomass consumed in 24 hours microgofcarbon/liter 1 real 0 Null None given