Lesson 32 Mineral Cycling - Alaska Geobotany Center

Nutrient supply in a coastal dune community
Bulk deposition and rainfall
• Primary nutrient source is from salt spray (8 times the
mineral ions of rain water.) Note the differences in the
salt-spray input of the fore dunes vs. lee side (e.g., for Ca,
80 vs 19 kg ha -1 yr -1 ).
• Calcium input is 35 kg ha -1 yr -1 , compared to 10.5 kg ha -1
yr -1 for an inland forested site.
• Much more Ca is retained in the more dense vegetation
on the lee side of the dune.
• In the sandy soils of the dunes, much of the calcium is
quickly leached away. (Note: more calcium is leached out
than arrived in the salt spray, indicating that CaCO 3
is
leaching from the sea-shell fragments in the dune.
• Turnover times are very short, 11-37 days for K, Na, and
Mg, and 32-206 days for Ca, reflecting the input from the
dissolved shells.
• There is no storage of nutrients in the sandy soils of the
dunes.