Premium
AUTOLYSIS KINETICS OF THE MARINE DIATOM DITYLUM BRIGHTWELLII (BACILLARIOPHYCEAE) UNDER NITROGEN AND PHOSPHORUS LIMITATION AND STARVATION 1
Author(s) -
Brussaard Corina P. D.,
Noordeloos Anna A. M.,
Riegman Roel
Publication year - 1997
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1997.00980.x
Subject(s) - biology , autolysis (biology) , diatom , nutrient , zoology , phosphorus , axenic , botany , ecology , biochemistry , chemistry , bacteria , genetics , organic chemistry , enzyme
Autolysis kinetics in axenic cultures of the diatom Ditylum brightwellii (West) Grunow were studied under nutrient limitation in continuous cultures and under nutrient starvation in batch‐mode cultures obtained by switching off nutrient supply in the continuous cultures. Under N limitation, the specific algal autolysis rates (δ, day −1 ) were found constant at 0.014 ± 0.002 day −1 over a broad range of specific dilution rates (D, day −1 ) (0.09–0.56 day −1 ), implying an intrinsic death factor independent of the physiologzc state of the algal cells. Under P limitation, 8 was inversely related to D and ranged between 0.067 and 0.005 day −1 at D = 0.17–0.44 day −1 . Under conditions of nutrient stamation, the degree of algal nutrient deficiency prior to stamation affected autolysis rates (δ b , day −1 ) and subsequently survival of the algal cultures. Nitrogen‐starved D. brightwellii showed highest δ b (maximum, 0.10 day −1 ) when precultured at the higher growth rates. Phosphorus stamation led to highest δ b (maximum, 0.21 day −1 ) in the cultures preconditioned at the lower steady state growth rates. The lower death rates for D. brightwellii under limitation and starvation of N compared to P suggest that D. brightwellii was better equipped to handle N than P deficiency. The present results showed that cell lysis induced by nutrient stress was a significant cause of mortality in D. brightwellii and provided more insight into the field distribution of this neritic diatom.