Remote Sensing and the Vertical Distribution of the Chrysochromulina Polylepsis Bloom in the Skagerak in 1988

Abstract

The present study contributes to explain the development of the C. polylepsis bloom and to evaluatethe importance of combined use of in situ monitoring and remote sensing techniques. The results show the difficulties to map the surface distribution of C. polylepsis via satellitedata and to judge the primary sources of water to the area. However, the satellite data indicate the temperature to be a possible prime factor in theacceleration of the bloom. In the later phase of the bloom, the C. polylepsis was associated with the warm surface water, but for large areas the algae was situated at a depth of 15-20 m, thus preventing direct mappingby remote sensing. C. Polylepsis has probably not been present in concentration above 0,5 mill cells/litre further north than Horten-Moss in the Outer Oslofjord. Subsurface layers of C. polylepsis reached concentrations of 16 mill.cell/litre at the entrance of the Outer Oslofjord, and chemical analysis indicated that among the plant nutriensphosphorus was limited.