Water-Column Studies near a Melting Arctic Iceberg

• Main Author: Shulenberger,Eric
• Other Authors: SAN DIEGO NATURAL HISTORY MUSEUM CA
• Format: Text
• Language: English
• Published: 1981
• Subjects: Biology; Snow; Ice and Permafrost; *WATER; *ANTARCTIC REGIONS; *PLANTS(BOTANY); *GLACIERS; *GREENLAND; *ICEBERGS; DENSITY; RATES; DIRECTION FINDING; NUTRIENTS; PROFILES; FEASIBILITY STUDIES; VERTICAL ORIENTATION; MELTING; WIND DIRECTION; MIXING; LOW DENSITY; PHYTOPLANKTON; SUNLIGHT; CHLOROPHYLLS; EUPHOTIC ZONES; Glacial icebergs; Water column studies; Plant biology; Antarctic; Arctic; Greenland; Antarc*; Ice; Iceberg*; permafrost; Phytoplankton
• Online Access: http://www.dtic.mil/docs/citations/ADA108304; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA108304

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)