Growth and consumption rates of bacterivorous Antarctic naked marine amoebae

• Published in: Marine Ecology Progress Series
• Main Authors: Mayes, D, Rogerson, A, Marchant, H, Laybourn-Parry, J
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter-Research 1997
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Antarctic; Antarc*
• Online Access: https://doi.org/10.3354/meps160101; http://ecite.utas.edu.au/49451

This is the first study to consider the growth and feeding rates of naked marine amoebae at temperatures below 5C. Specific growth rates were calculated for 5 Antarctic isolates, Platyamoeba australis, Mayorella sp., Metachaos sp., Vannella sp., and an unidentified vahlkampfiid amoeba. Growth rates ranged between 0.08 x 10 -2 and 2.9 x 10 -2 h -1 corresponding to generation times of 866.2 and 23.9 h, respectively. All isolates grew at temperatures down to -2C and showed optimal growth at 2C although one species grew best at 0C. A direct counting method was used to estimate bacterial feeding rates of P. australis and the vahlkampfiid amoeba. Rates varied as a function of prey density but were largely independent of temperature. Overall, amoebae consumed between 0.5 and 66.4 bacteria amoeba -1 h -1 , equivalent to 0.3 and 38.0 pg C cell -1 h -1 . Growth efficiencies estimated for these 2 amoebae were low, typically < 2%, suggesting that amoebae incur high energetic costs for life at low temperatures.