Water-Column Studies near a Melting Arctic Iceberg,
Abstract
Glacial icebergs contain large amounts of nitrate, an important phytoplankton nutrient. Low density iceberg meltwater, in rising, mixes with euphotic zone water nearby, wherein NO3 is in low concentration. Rising meltwater may also entrain nutrient-rich deeper waters and raise them to sunlit depths. Sixteen vertical profiles of nutrients (PO4, NO3, SiO2), chlorophyll-a, and physical parameters were taken near a Greenland iceberg at approx. 50 deg. N, 50 deg. W in May-June 1980. Chlorophyll profiles show very pronounced maxima at or just below the maximum rate of change of water density vs. depth; profile forms are heterogeneous (no 'typical' form is evident). No enhancement of chlorophyll concentration was found re distance from or direction to the iceberg. Effects of mixing on NO 3 concentrations are marginally detectable, but no 'wake' or 'downwind' effects were observed. The iceberg does not appear to grossly perturb water column plant biology nearby, but measures of rates of productivity might show otherwise, particularly near larger (e.g. Antarctic) icebergs. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1981
- Accession Number
- ADA108304
Entities
People
- Eric Shulenberger