Mikhail, S., Gergis, W. (2008). Temperature, salinity and light duration dependence on the growth and cellular carbon and nitrogen contents of the epiphytic diatom,Achnanthes longipes Agardh. Egyptian Journal of Aquatic Biology and Fisheries, 12(4), 185-202. doi: 10.21608/ejabf.2008.2012
Samia Mikhail; Wagdy Gergis. "Temperature, salinity and light duration dependence on the growth and cellular carbon and nitrogen contents of the epiphytic diatom,Achnanthes longipes Agardh". Egyptian Journal of Aquatic Biology and Fisheries, 12, 4, 2008, 185-202. doi: 10.21608/ejabf.2008.2012
Mikhail, S., Gergis, W. (2008). 'Temperature, salinity and light duration dependence on the growth and cellular carbon and nitrogen contents of the epiphytic diatom,Achnanthes longipes Agardh', Egyptian Journal of Aquatic Biology and Fisheries, 12(4), pp. 185-202. doi: 10.21608/ejabf.2008.2012
Mikhail, S., Gergis, W. Temperature, salinity and light duration dependence on the growth and cellular carbon and nitrogen contents of the epiphytic diatom,Achnanthes longipes Agardh. Egyptian Journal of Aquatic Biology and Fisheries, 2008; 12(4): 185-202. doi: 10.21608/ejabf.2008.2012
Temperature, salinity and light duration dependence on the growth and cellular carbon and nitrogen contents of the epiphytic diatom,Achnanthes longipes Agardh
1National Institute of Oceanography and Fisheries, Alexandria, Egypt
2National Institute of Oceanography and Fisheries, AleWagdy L. Gergisxandria, Egypt
Abstract
Achnanthes longipes Agardh cells were isolated from glass slides submerged in the Eastern Harbour of Alexandria. Addition of D-600 (10& 25 μM) and EDTA (10-3M) was sufficient to prevent adhesion and aggregation of A. longipes cells and get homogenous free cells inocula for culture experiments. The influence of 52 combinations of salinity (5-40 at 5 intervals) and temperature (10o-25oC, at 5oC intervals) under continuous light and 12:12 light/dark cycle on chlorophyll a content, the maximum doubling time, cellular carbon and nitrogen of Achnanthes longipes was examined under constant light intensity (70-80 μE m -2 S -1). No growth was detected at 5 salinity levels with all temperatures tested, and under the combination of 15oC-10 salinity. Maximum Chl. a content during the exponential phase was almost the same at the two light regimes (about 1.2 μg ml-1). Based on Chl. a variations by days, A. longipes showed its maximum growth rate and doubling time (1.18 and 0.82 d-1, respectively) at 20oC-30 salinity (continuous light) and 1.6 and 1.11 d-1, respectively at 20oC-25 salinity (light/dark cycle). A rising in temperature from 15oC to 20oC caused about 1.8 fold increases in the doubling time of Chl. a at the two light regimes. The results indicated that Chl. a and carbon proceeded in parallel during the exponential phase under the light regimes, and the increasing in carbon content and Chl. a content accompanied an increasing in temperature. The carbon content was consistently lower in continuous light cultures than in the corresponding light/dark cultures. No definite trend was found between nitrogen and changed temperature and salinity (continuous light), while nitrogen generally increased with increasing temperature under the light/dark cycle. The maximum carbon/nitrogen was measured at 25oC with salinity range of 35 - 40,it was about two-fold higher at the light/dark (40.03). The carbon: chlorophyll ratio showed a steady increase by days, and varied considerably with changed temperature. However, there was no characteristic relation between temperature,growth rate and carbon: chlorophyll.
View on SCiNiTO
Top