THE MICROBIAL FOOD-WEB ASSOCIATED WITH THE ICE ALGAL ASSEMBLAGE - BIOMASS AND BA

2020-03-26 14:29:05

PQ Marine Canada HNAN RIMOUSKI

责任者: LAURION, I;DEMERS, S;VEZINA, AF 单位: UNIV QUEBEC,DEPT OCEANOG,RIMOUSKI,PQ G5L 3A1,CANADA.;INST MAURICE LAMONTAGNE,MONT JOLI,PQ G5H 3Z4,CANADA.;INST NATL RECH SCI OCEANOL,CTR OCEANOG RIMOUSKI,RIMOUSKI,PQ G5L 3A1,CANADA. 来源出处: MARINE ECOLOGY-PROGRESS SERIES, v 120, APR 1995, p 77- 87 摘要: Biomass and grazing activity of sea ice microorganisms smaller than 20 mu m were studied at Resolute Passage in the Canadian Arctic during the algal bloom in spring 1992. The spatial variation in biomass beneath a 225 m(2) area with changing snow cover was almost as great as the temporal change (under a constant snow cover) over the 5 wk sampling period. Cell density in the ice varied from less than or equal to 7 x 10(7) to 2.6 x 10(9) cells m(-2). Total bacterivory of the protozoan community was assessed by measuring the disappearance of fluorescently labelled bacteria over 20 h. Feeding rates by heterotrophic nanoprotozoans (HNAN) were high at the beginning of the sampling period (late April) but decreased to very low values by the end of May; HNAN clearance rates ranged from less than or equal to 3 to 86 nl HNAN(-1) h(-1) (mean = 12 nl HNAN(-1) h(-1)) while ingestion rates ranged from less than or equal to 3 to 64 bacteria HNAN(-1) h(-1). The carbon budget analysis indicates that bacteria alone could not provide the required energy for the observed protozoan growth. The results suggest that a shift in the grazing behavior of HNAN occurred during the bloom season, modifying the microbial food web dynamics. 关键词: NANOPROTOZOAN; BACTERIVORY; ARCTIC; SEA-ICE; MCMURDO SOUND; PLANKTONIC COMMUNITY; TROPHIC INTERACTIONS; POPULATION-DYNAMICS; PELAGIC ECOSYSTEMS; ANTARCTICA; LOOP; MARINE; WATER POPULATION-DYNAMICS; PELAGIC ECOSYSTEMS; ANTARCTICA; LOOP; MARINE; WATER