Acceptance and utilization of LTER data requires that:
FILE NAME: PRINCIPAL INVESTIGATOR: OTHERS: KEYWORDS: lake, flagellate, nanoflagellate, heterotrophic, cryptophyte, ciliate, Antarctica, limnology, abundance, microzooplankton
ABSTRACT: 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 the abundance of heterotrophic nanoflagellates, cryptophytes, and ciliates found at various depths in Lake Fryxell and Lake Hoare.
VARIABLES: location, date, depth (m), HNAN abundance (# / ml), cryptophyte abundance (# /ml),
ciliate abundance (# / liter), file name
RESEARCH LOCATION: Two perennial ice-covered lakes, Lake Fryxell and Lake Hoare, in the Taylor Valley, Southern Victoria Land, Antarctica (77°S, 162°E) were sampled. Lake
Fryxell has a maximum depth of 20m and is a permanently stratified meromictic lake with a conductivity of 1.2 to 2.0 mS/cm in the upper mixomolimnion and 4.1 to 8.4 mS/cm in the lower
anoxic monomolimnion. Water temperatures during the summer range from 0.01°C to 2.7°C, with temperature increasing with depth. The chemocline is situated at 9.5m. In contrast, Lake
Hoare is unstratified during the summer and is freshwater. It has a maximum depth of 34m. Summer temperatures in the water column ranged between 0.01°C and 1.0°C.
METHODS: The water column was sampled at the deepest point in each lake with a 2.21 Niskin bottle, through a hole drilled in thick ice cover (approximately 4m thick). Duplicate 60ml
samples from each depth were fixed in buffered glutaraldehyde to a final concentration of 2% and stored in the dark at 4°C prior to being analyzed. For HNAN and cryptophyte counts, 30-50ml of the sample was stained with DAPI, filtered onto a 2.0 m polycarbonate
membrane filter and viewed under epifluorescence. Twenty Whipple grids were counted on each filter to determine
mean abundance. For ciliates, duplicate 500 ml 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.
TIMING: Samples were gathered on the following dates and locations: LOCATION DATE Lake Fryxell Oct 27, 1996
Lake Hoare Oct 26, 1996
CITATIONS: Roberts, Emily C. and Johanna Laybourn-Parry. 1998. Mixotrophic cryptophytes and their
predators in the Dry Valley lakes of Antarctica. Freshwater Biology. In Press.
COMMENTS:
STATUS: Restricted Access (Type IV).
VARIABLE DESCRIPTION:
VARIABLE TYPE DESCRIPTION UNITS MISSING VALUE INDICATOR MINIMUM MAXIMUM PRECISION Location Text Name of lake where measurement was made none Required entry n/a n/a n/a Date Date Date on which sample was gathered mmm-yyyy Required entry 01-Nov-1991 30-Jan-1999 dd Depth (m) Number Depth at which sample was drawn from lake meters Required entry 1 30 1 HNAN Abundance (# / ml) Number Number of heterotrophic nanoflagellates/milliliter of lake water number / milliliter Null 0 n/a 1 Cryptophyte Abundance (# / ml) Number Number of cryptophytes/milliliter of lake water number / milliliter Null 0 n/a 1 Ciliate Abundance (# / liter) Number Number of ciliates/liter of lake water number / liter Null 0 n/a 1 File Name Text Name of file in which data was stored Null n/a n/a n/a LOG: 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/emily.xls" and
"/data1/data/lakes/plankton/laybourn-parry/ciliate.xls". 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.
NOTE: Data contained in these files has been subjected to quality
control standards imposed by the investigator. The user of this data
should be aware that, while efforts have been taken to ensure that these
data are of the highest quality, there is no guarantee of perfection
for the data contained herein and the possibility of errors exists. If
you encounter questionable data, please contact the MCM LTER data manager
(; (303)492-4639) so that the data can be
corrected or qualified. Thus, these data may be modified and future
data will be appended.
Nov 9, 21, 27, 1996
Dec 12, 26, 1996
Jan 2, 9, 24, 1997
Nov 2, 12, 18, 28, 1997
Dec 5, 16, 29, 1997
Jan 8, 20, 1998
Nov 2, 10, 23, 1996
Dec 3, 13, 23, 1996
Jan 12, 26, 1997
Oct 31, 1997
Nov 7, 15, 26, 1997
Dec 10, 26, 1997
Jan 6, 17, 26, 1998
none