Soil Formation in Iceland
In the last century, recession of outlet glaciers of the Vatnajökull ice sheet has exposed glacial ground moraine and outwash deposits to pedogenesis (soil formation) and floral colonization. In Skaftafell National Park, the Skaftafellsjökull has retreated over 1000 m in the last 75 years, leaving a broad proglacial plain interrupted by recessional morainal ridges. Formation of very young soils on the glacially derived volcanic sediments (andic cryofluvents) involves the accumulation of organic carbon in the uppermost soil layer and minor root turbation.
Organic carbon content in this layer, as measured by combustion analysis using the LECO Truspec C/N analyzer in the Department of Biological Sciences, ranges from a high of >3% on older (60+ years), more heavily vegetated surfaces, to less than 0.5% on outwash surfaces less than 20 years old. The oldest land surfaces (more than 100 years) are almost completely vegetated, with mats of mosses up to 17 cm thick and birches averaging over 1 meter height. Surfaces less than 65 years old are at most 75% vegetated, with moss thickness averaging ~6 cm. Surfaces that are 25 years old or less are at most 30% covered, with wooly willow dominating the shrub layer. The floral cover on the youngest surfaces is 5% or less, with moss and shrubs mainly on sheltered slopes.
The nearby Svinafellsjökull has a history of recession interrupted in the late twentieth century by episodes of surging, and consequently, a more complex periglacial topography. No clear correlation exists between land surface age and soil carbon content for this glacier, possibly, in part, due to the effects of continued livestock grazing in this area.
This research was presented at the meeting of Northeastern section of the Geological Society of America in March 2007 and at Scholars Day, April, 2007, by Annie Walker and Jessica Curry.
This research continued in Summer 2008 with additional field work performed by the members of the BIO 126 class. These students collected new data measuring floral diversity as a function of surface age.
See video clips of the Le Moyne 2008 trip on YouTube! Click on the links below.
1) The group hiking in to the front of Skaftafellsjokull (Skaftafell Glacier) at Skaftafell National Park.
2) A visit to the Jokulsarlon (Glacier Lagoon).