Effects of temperature and glucose concentration on the growth and respiration of fungal species isolated from a highly productive coastal upwelling ecosystem

Respiration and growth rates were measured in five species of fungi (Penicillium decumbens, P. chrysogenum, Acremonium strictum, Fusarium fujikuroi and F. sporotrichioides) isolated from the upwelling system off the coast of central-south Chile to determine the effects of glucose availability and temperature. Growth was monitored by epifluorescence microscopy, ATP measurements, and optical density. Oxygen consumption was recorded via a respirometer with Optode sensors. Although species-specific responses were found, overall both respiration and growth increased with temperature and glucose concentration. Growth of P. decumbens, F. sporotrichioides and F. fujikuroi was more favoured by temperature when glucose remained stable. P. chrysogenum had a particular growth pattern, which seemed to be more linked to glucose availability than directly to temperature. Growth of F. sporotrichioides and A. strictum responded to the synergistic interaction between temperature and glucose. Values of Q sub(10) for fungal respiration ranged from 2.2 to 6.7, indicating a strong temperature-dependence of respiration rates, especially in A. strictum and F. sporotrichioides.