Human Disturbance Effects on soils

Summary

Abstract:

Concerns over environmental disturbance in the McMurdo Dry Valleys are increasing with increasing foot traffic from tourists and scientist. The effect of pedestrian disturbance were monitored by comparing the species composition, depth distribution and soil properties between adjacent high-, low- and no- traffic sites. This study began in the austral summer 1995/1996.

Date Range:

October 1, 1995 to April 1, 1997

Dataset(s)

Variables (click to expand):

LOCATION

Label:
Definition: Name of area where measurement was made
Type: Nominal
Missing values: None specified

DATE_TIME

Label:
Definition: Date on which sample was gathered
Type: Date/time
Date format: mm/dd/yyyy
Missing values: None specified

SAMPLE #

Label:
Definition: Sample ID
Type: Nominal
Missing values: None specified

SOIL WATER CONTENT (%)

Label:
Definition: Percent water found in soil
Type: Physical quantity
Unit: dimensionless
Maximum: Not specified
Minimum: Not specified
Precision: Not specified
Missing values:
- Required Entry = None given

COMMENTS

Label:
Definition: Helpful hints about the sample
Type: Nominal
Missing values: None specified

FILE NAME

Label:
Definition: Name of file in which data was stored
Type: Nominal
Missing values: None specified

File:

9597diso.csv [1] (8.64 KB)

...or query the dataset by variables and dates of interest:

[2]

Dataset ID:

233

People

Principal Investigator(s):

Diana Wall [3]

Ross A. Virginia [4]

Contact:

McMurdo Dry Valleys LTER [5]

Associated Personnel:

Associated Researcher

Field Crew

Data Manager

Methodology

Methods:

Sampling bags were prepared with one sterile 'Whirlpak' bag and clean plastic scoop per sample. Soils were sampled from three areas: heavy traffic (H), light traffic (L) and control (C) where soils had not been walked upon; and at 2.5 and 10 cm depths. The location of the sampling was recorded each year 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 5 C 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. Approximately 200cm3 of soil was placed in a pre-weighed 800mL plastic beaker. Rocks greater than 3-4mm in diameter were removed from the sample. A sub-sample of approximately 50g was removed and placed in a pre-weighed aluminum dish, and weighed on a balance accurate to 0.01g. This sample was dried at 105C for 24 hours. The sample was removed, placed in desiccator to cool down, and re-weighed. These data were used to calculate water content of the soil and to express data as numbers of soil organisms per unit dry weight of soil.

Maintenance:

This file was created by Mark St. John on 9 Nov 1998, using raw data from the Excel workbook '9612diso.raw'. The file format was suggested by the LTER data manager, to conform with the relational database structure.

Research Section:

Soils [15]

Core Areas:

disturbance [16]
populations [17]

MCM Keywords:

Antarctica [18]
LTER [19]
soil [20]
soil moisture [21]