Ref ID : 1883
Helen Butler and Andrew Rogerson; Growth potential, production efficiency and annual production of marine benthic naked amoebae (gymnamoebae) inhabiting sediments of the Clyde Sea area, Scotland. Aquatic Microbial Ecology 10:123-129, 1996
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A substantial population of naked amoebae is present in marine sediments, but little is known about their role in benthic microbial food webs. Central to elucidating this role is an understanding of their growth potential, and the present study measures growth rate of 10 species of naked amoebae isolated from benthic sediments in the Clyde Sea area, Scotland, UK. Across the range of species and temperatures examined (5 to 20 degrees C), generation times varied from 11 to 130 hr. Temperature had a marked effect on growth rate, with the slowest rates at the lowest temperature. Temperature also generally influenced the mean cell volume of cells, with many species showing increased cell size at lower temperature. Consequently, it was possible to compute a significant regression of log10 generation time (G, hr) against log10 cell volume (V, um3) using the combined data regardless of temperatures [log G=0.231logV+1.010 (p=0.004)]. This relationship may have application in the estimation of generation times of naked amoebae with known cell volumes. Gross growth efficiencies ranged between 11.7 and 79.7% with an overall mean of 36.1%. The growth data were combined with published information on the abundance of marine benthic amoebae to provide a first estimate of annual production by this group in fine marine sediments. Annual production estimates were between 7.60 and 15.8 kJ m-2 yr-1, implying that annual consumption of bacteria by naked amoebae is of the order 21.1 to 43.8 kJ m-2 yr-1.