nematodes

Seasonal Effects on Electrical Conductivity

Abstract: 

Investigation of the effect of long-term variation in soil moisture and soil temperature on nematode anhydrobiosis as part of the McMurdo Dry Valleys Long Term Ecological Research (LTER) project. The percent of anhydrobiotic (coiled) nematodes with relation to season was determined. The study took place on three separate dates during the 1997-1998 austral summer: 21 November 1997, 16 December 1997, and 13 January 1998.

Core Areas: 

Associated Personnel: 

686

Dataset ID: 

242

Short name: 

seec

Data sources: 

seec

Methods: 

 Sampling was done by using a clean plastic scoop and collecting soil to a 10-cm depth.  Soil samples were taken for organism enumeration, moisture content, and salinity analysis as follows: Sampling bags were prepared with one sterile 'Whirlpak' bag and clean plastic scoop per sample. Samples were taken from within the 10 cm diameter circular area of each plot. The location of the sampling was recorded so that areas were not re-sampled. Using the plastic scoop, soil was collected to 10 cm depth. Very large rocks (>20 mm diameter) were excluded from the sample. The soil was shoveled into the 'Whirlpak' bag until three quarters full (about 1.5 kg soil). The soil was mixed well in the bag, then the bag was closed tightly, expelling as much air as possible. The soil samples were stored in a cooler for transportation. On return to the laboratory (within 8 hours of sampling), the soils were stored at 4C until further processing.  In the laboratory, soil samples were handled in a laminar flow hood to prevent contamination. The Whirlpak bags of soil were mixed thoroughly prior to opening.
 
Subsamples of soil were taken for EC analysis. 150ml of deionized water was added to 25g of soil in a clean, DI- rinsed glass 150-ml tall form beaker (coarse fragments >3-4 mm were removed). The samples were stirred until thoroughly mixed (about 20 sec). After sitting for 10 seconds, the samples were stirred again and an initial reading was taken with a YSI 30 conductivity meter. Regarding EC units on the datasheet, the meter took readings at micromhos. The numbers were converted to dS/m (deciSeimens/meter) by dividing by 1000.
 

Maintenance: 

This file was created by Pilar Tillberg on 10 May 2001, using raw data from the Excel workbook '9711seec.raw'. The file format was suggested by the LTER data manager, to conform with the relational database structure. [PT 10 May 2001].

On 2016, metadata was enhanced for better preservation

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