The Journal of Foraminiferal Research; October 2002; v. 32; no. 4;
p. 434-439; DOI: 10.2113/0320434
© 2002 Cushman Foundation for Foraminiferal Research
TEMPERATURE DEPENDENCE OF PSEUDOPODIAL ORGANELLE TRANSPORT IN SEVEN SPECIES OF FORAMINIFERA AND ITS FUNCTIONAL CONSEQUENCES
Tomas Cedhagen1 and
Hans Frimanson2
2 Dr. Sydows Gata 3E, SE-413 24 Gothenburg, Sweden.
1 (Corresp. address): Department of Marine Ecology, Institute of Biological Sciences, University of Aarhus, Finlandsgade 14, DK-8200 Aarhus N, Denmark, cedhagen{at}biology.au.dk.
The rate of transportation of granules (mitochondria) within the pseudopodia was studied in seven sublittoral foraminiferan species from the west coast of Sweden: Astrorhiza limicola, Cornuspira foliacea, Crithionina granum, Globipelorhiza sublittoralis, Phainogullmia aurata, Quinqueloculina seminulum and Technitella legumen. The average organelle velocity was found to increase with temperature in all species. Five of these species showed a similar increase of velocity (about 24 µm/s at 2 °C, to about 68 µm/s at 17 °C). The velocity of Quinqueloculina seminulum, however, increased far more than the others at high temperatures (912 µm/s at 17 °C), while the velocity of the komokiacean Globipelorhiza sublittoralis was far less than all others at all temperatures (about 2 µm/s at 2 °C to 4 µm/s at 13 °C). The increased pseudopodial organelle velocity is interpreted to reflect an increased metabolism and consequently an increased demand for the exchange of oxygen, waste products, and material through the pseudopodial membrane. The much branched granuloreticulose pseudo-podial network increases the respiratory surface many-fold. We suggest that this is a factor allowing the extreme increase in cell size in foraminiferans.
Copyright © 2008 by Cushman Foundation for Foraminiferal Research