The Biodiversity and Biogeochemistry of Cryoconite Holes from McMurdo Dry Valley Glaciers, Antarctica

Figures & data

FIGURE 1. Map of locations of sampled glaciers within Taylor Valley

FIGURE 2. Schematic illustration of glacial zones (courtesy of F. D. Granshaw)

FIGURE 3. Diameter (cm), depth (cm), and sediment mass (g/cm²) (mean ± standard error) of cryoconite holes of Commonwealth (Common), Canada, Howard, Hughes, and Taylor glaciers. Different letters indicate significant differences at P ≤ 0.05. Capital letters relate to differences in diameter, lowercase letters to differences in depth, and italic letters to differences in sediment mass

FIGURE 4. Abundance of invertebrates (# 100 g⁻¹ dry sediment) (mean ± standard error) in cryoconite holes of Commonwealth (N = 24), Canada (N = 24), Howard (N = 24), Hughes (N = 24), and Taylor (N = 38) glaciers. Black bars indicate tardigrades and checked bars rotifers. Capital letters indicate significant differences at P ≤ 0.05 among glaciers for rotifers, and lowercase letters indicate significant differences at P ≤ 0.05 among glaciers for tardigrades

FIGURE 5. Concentrations of dissolved organic carbon (DOC) (mean ± standard error) in cryoconite holes of Commonwealth (N = 24), Canada (N = 24), Howard (N = 24), Hughes (N = 24), and Taylor (N = 38) glaciers. Letters indicate significant differences at P ≤ 0.05

FIGURE 6. Concentrations of ammonium (NH₄ ⁺) and nitrate (NO₃ ^–) (mean ± standard error) in cryoconite holes of Commonwealth (N = 24), Canada (N = 24), Howard (N = 24), Hughes (N = 24), and Taylor (N = 38) glaciers. Dashed lines show ammonium levels and continuous lines show nitrate levels. Capital letters indicate significant differences at P ≤ 0.05 among glaciers for nitrate, and lowercase letters indicate significant differences at P ≤ 0.05 among glaciers for ammonium

FIGURE 7. Concentrations of (a) cations: sodium (Na⁺, continuous line), calcium (Ca⁺², dashed with triangles line), potassium (K⁺, dashed with squares line), and magnesium (Mg⁺², dashed with crisscross line) and (b) anions: chloride (Cl^–, continuous line) and sulfate (SO₄ ^–2, dashed line) (mean ± standard error) in cryoconite holes of Commonwealth (N = 24), Canada (N = 24), Howard (N = 24), Hughes (N = 24), and Taylor (N = 38) glaciers. Capital letters indicate significant differences at P ≤ 0.05 among glaciers for Na⁺ and SO₄ ^–2, italic capital letters indicate significant differences at P ≤ 0.05 among glaciers for Ca, lowercase letters indicate significant differences at P ≤ 0.05 among glaciers for K, and Cl, and italic lowercase letters indicate significant differences at P ≤ 0.05 among glaciers for Mg

FIGURE 8. Acidity (pH, dashed line) and salinity (EC, continuous line) (mean ± standard error) in cryoconite holes of Commonwealth (N = 24), Canada (N = 24), Howard (N = 24), Hughes (N = 24), and Taylor (N = 38) glaciers. Capital letters indicate significant differences at P ≤ 0.05 among glaciers for salinity, and lowercase letters indicate significant differences at P ≤ 0.05 among glaciers for pH

Table 1 Taxonomic biotic composition of cryoconite holes on glaciers in Taylor Valley, Antarctica

Table 2 Relationship between invertebrate abundance and properties of cryoconite holes as the best-fitted multiple regression model

Table 3 Morphological and invertebrate differences between sampling seasons, elevations, and sides on Canada Glacier. Data represent averages