One key challenge for conducting comprehensive esophageal imaging in vivo with SECM is that the focal plane of the objective lens must be consistently kept at a designated imaging depth within the tissue.
The objective lens was translated along the depth dimension to minimize the difference between the tissue surface coordinate x p and the target coordinate x t, which subsequently moved the SECM focal plane to a designated target depth below the tissue surface.
This depth, designated D, can theoretically occur at about 100 metres (300 feet) in large, deep, midlatitude lakes.
Arsenic distribution was determined following earthworm bioturbation in artificial soil columns that were initially constructed with a contaminated layer of designated thickness and depth.
This parameter was designated the penetration depth of the biopsy needle (mm).
To correct this bias, we developed a Python script (Supporting Information, File S1) that called a heterozygote if both verified alleles had a depth of more than two and the total read depth at the locus was 10X or greater; this was the minimum depth we designated previously.
For each land cover type, the following winter scenarios were applied: (1) reference plot, designated "Ref", with natural depth of snowpack, (2) no-frost, "NoFr" (simulation of snow addition using artificial heat insulation material), and (3) no-snow, "NoSn" (removal of snowpack).
Observers were instructed to adjust the dots of the second row in order to match the apparent surface profile in depth along the designated scan line.
At each site, snail collections were performed at the lake edge, which was often marshy, designated site A, and at depth (~1 m) in the lake as designated site B. The study was conducted from January 2009 to May 2011 and typically involved coordinated sampling at each site in a monthly timetable.
