The chlorophyll a content was measured at 62 oceanographic stations. At each station samples were collected from eight standard depths between the water surface and 150 m. Integrated values (chlorophyll α mg/m2) are used in the presentation of the results and discussion. The recorded quantities of chlorophyll α were rather high, amounting to as much as 634 mg/m2. The areas with high chlorophyll a content (> 200 mg/m2) were located in the region of the Anvers Island and Brabant Island, on the shelf around Joinville Island and opposite the Antarctic Sound, close to Clarence Island and beyond the regions recommended in the BIOMASS-SIBEX programme to the east and south of the South Orkney Islands. In the acetonie extracts of photosynthetizing pigments large quantities of phytoxanthin were found using the TLC method, what precludes the use of the Lorenzen method for determination of chlorophyll α and its degradation products.