GERMINACIÓN DE ESTADOS DE RESISTENCIA DE DIATOMEAS Y DINOFLAGELADOS EN SEDIMENTOS MARINOS DE DOS ÁREAS DE SURGENCIA DE CHILE/GERMINATION OF RESTING STAGES OF DIATOMS AND DINOFLAGELLATES IN MARINE SEDIMENTS FROM TWO UPWELLING AREAS OF CHILE

摘要

With the aim to assess germination of diatom and dinoflagellates resting spores we cultured under laboratory conditions surface sediments collected in the Mejillones Bay (23° S) and off Concepción (36° S), Chile. These sediments were cultured in the laboratory with a 12:12 h L/D cycle, light intensity of 140 µmol m^sup 2^ s^sup -1^, at room temperature, and with a salinity of 35.4 units. The main diatom species in the sediments were Skeletonema japonicum and Chaetoceros spores. Dinoflagellate cysts were represented by the genera Diplopsalis, Scrippsiella, and Woloszynskia and the species Protoperidinium avellanum and P. leonis. After 20 days of culturing, germination and growth was recorded for S. japonicum and several of the Chaetoceros species, although their abundance was low. The diatoms with abundant growth were Stauroneis legleri, Pseudostaurosira trainorii, Pseudostaurosira sp.1, Pseudostaurosira sp. 2, and Navicula pseudoreinhardtii. The dinoflagellate Woloszynskia sp. also germinated and grew abundantly in the culture. This study includes a brief description of the cultured species and some aspects of their ecology. In addition, we discuss the possible causes for low levels of germination in planktonic diatoms, finding low dissolved oxygen concentrations in the bottom waters to be one of the main factors that presumably affected the survival of resting spores in the sediment. [PUBLICATION ABSTRACT]