Characteristics of Growth and Fluorescence of Certain Types of Algae during Acclimation to Different Temperatures under Culture Conditions

Аннотация

The paper examines the temperature dependence of the specific growth rate and ratio of variable to maximum fluorescence (F_V/F_M) in a number of marine planktonic algae from collections of cultures. It determines the optimum growth temperatures (T_opt), upper and lower limits of the tolerance zone, and in some cases, changes in the dynamics of these parameters outside the tolerance zone. Temperature characteristics of the species corresponded to the growth conditions of these species in a natural environment. Prolonged stress exposure to a low positive temperature (4–6°C) was reversible; recovery of the growth rate and F_V/F_M was observed immediately after the temperature increased. In diatoms, temperatures 2–3°C above the T_opt for diatoms induced gradual degradation of the culture, which, depending on the duration of exposure, could lead to the death of algae. Springtime dinoflagellates exhibited higher temperature resistance and remained viable at temperatures 5–8°C above T_opt with lower specific growth rates. The increasing portion of temperature dependence of the specific growth rate approximated a linear dependence; the regression coefficient is 0.08–0.13 for diatoms and 0.03–0.11 for dinoflagellates. The normalized values for this parameter (the relative value of change in the specific growth rate, %) was 5.3 ± 0.4 for diatoms and 6.4 ± 0.5 for dinoflagellates for 1°C of temperature change. Dinoflagellates exhibited larger values for the Q₁₀ parameter. F_V/F_M for most species had high values in the entire range of temperatures at which the algae maintained a steady-state growth. A drop in this parameter outside the limits of the tolerance zone was associated with the temperature-induced inhibition of growth processes.