INSTRUMENTS FOR MEASURING SUBICE ALGAL PROFILES AND PRODUCTIVITY IN-SITU

Instruments have been developed for the in Situ measurement of concent ration and productivity of bottom ice algal layers in Resolute Passage , eastern Canadian Arctic. Measurements are accomplished by deploying an instrument on an arm articulated remotely through a hole in the ice , sampling the subice surface, and finally recovering the instrument a nd sample. The first instrument is an incubation system that is used t o measure in situ productivity of a subice core. Results show the exte nt and range of productivity in bottom ice, with low and high biomass at the commencement of the algal bloom and near the end of the bloom p eriod, respectively. The second instrument is a reflectance meter that can be used to measure chlorophyll profiles at the subice surface. Th e meter was calibrated against measured chlorophyll concentrations of extracted cores. After calibration the instrument can be used to measu re integrated chlorophyll (milligrams per square metre) and profiles ( milligrams per cubic metre) rapidly and synoptically. Deployment of th e arm coupled with a plankton pump sampler is also briefly described.