Photoacclimation of phytoplankton in different biogeochemical provinces of the Southern Ocean and its significance for estimating primary production. Die Photoakklimatisierung von Phytoplankton in verschiedenen biogeochemischen Provinzen des Antarktischen Ozeans und ihre Bedeutung fuer die Abschaetzung der Primaerproduktion

The present thesis summarises the results from a series of publications where the production process of phytoplankton was studied in the Southern Ocean in order to assess its regional variability as defined by provinces and to provide basic data which can be used as bases for the estimation of productivity in the Southern Ocean. In December to January 1995-96 during the German JGOFS cruise ANTXIII/2 various bioptical measurements, including the spectral composition of the underwater light field and phytoplankton absorption characteristics, and experiments on the relationship between photosynthesis and irradiance (P versus E curves) in the PAR and UV range were performed in the Atlantic sector of the Southern Ocean. These data were used to calculate primary production rates integrated over the water column for various stations; in addition, a diagnostic model was established to estimate synoptically the mesoscale distribution of primary production at the ambient region of the Antarctic Polar Front by using in addition to the P versus E relationships and absorbance characteristics obtained at certain points (stations) within the survey area, on-line chl a and underwater light data measured by sensors contained in a towed undulating vehicle. The composition of the phytoplankton communities was derived from HPLC data on pigment composition and from the distribution of the various size fractions on total chl a. (orig.)Summary in GermanSIGLEAvailable from TIB Hannover: RN 9219(341) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman