Investigations into movement of ice worms (Mesenchytraeus solifugus: Enchytraeidae) and their distrubution across the Harding Icefield, Alaska
Thomas JP. 2006. Investigations into movement of ice worms (Mesenchytraeus solifugus: Enchytraeidae) and their distrubution across the Harding Icefield, Alaska. Alaska Pacific University
Our study investigated annelid ice worm (Mesenchytraeus solifugus: Enchytraeidae) movement and response to surface manipulations on the Harding Icefield, Alaska. Ice worm penetration into surface firn and ice on the Harding Icefield and depth distribution between 0700 – 1200 hours were investigated experimentally. Snow structure was more indicative of burrowing rate than density, with worms borrowing into firn approximately 5 times faster than crystalline ice. Most worms remained within 10 – 30 cm of the surface. Additionally, we performed manipulation experiments on two glaciers, one in July and the other in August, to observe ice worm response to differences in surface algae. At low algal abundance in July, worm density correlated with algal abundance; however in August, when more algae were on the surface, worm density decreased in artificially enriched plots. Ice worm density decreased in plots where surface algae were artificially reduced, one week and one month after manipulations on both glaciers. Our results suggest that ice worms actively forage on glacier surfaces, and respond to differences in surface composition. We also surveyed ice worm density across the Harding Icefield, and using GIS software constructed a model based on elevation and proximity to icefield perimeter that predicts relative worm density.