Production of extracellular polymeric substances (EPS) by benthic diatoms: effect of irradiance and temperature

Effects of temperature on photosynthetic parameters and TEP production in eight species of marine microalgae

“…TEP formation, and carbon excretion in general, is known to be strongly influenced by nutrient status; however, in the present study, growth was not nutrient limited and was controlled only by temperature. Contrary to Wolfstein & Stal (2002), who observed higher EPS production per chl a unit at low temperature in batch culture for the diatom Cylindrotheca closterium, we observed for the tested diatoms an increase of EPS production up to an optimal temperature and then a decrease at high temperature. For the 3 diatoms, and in contrast to the other species, TEP production was significantly linearly related to photosynthetic activity (Fig.…”

“…Microalgae manifest a range of physiological responses to temperature changes (Thompson 2006), but the effect of temperature on carbon excretion has rarely been studied. In non-thermal acclimated cultures of benthic diatoms, Wolfstein & Stal (2002) observed that carbon excretion relative to biomass was higher at low temperature. Parallel temperaturedependent changes in photosynthesis and dissolved organic carbon (DOC) excretion were observed in batch cultures of the chlorophyte Chlorella vulgaris and the cyanobacterium Synechococcus sp., while DOC excretion was temperature independent in the haptophyte Isochrysis galbana (Zlotnik & Dubinsky 1989).…”

“…Applying this model to our data for pelagic diatoms, it can be argued that under thermal acclimation the EPS type2 would not be formed, while EPS type1 production would be coupled with carbon production. In the study of Wolfstein & Stal (2002), EPS production of C. closterium may have decreased at low temperature with increasing age of the culture as a result of thermal acclimation and decreasing thermal stress. Analyses of TEP and EPS composition as a function of thermal acclimation would be an interesting next step for further investigation.…”

Growth form defines physiological photoprotective capacity in intertidal benthic diatoms

“…In addition, while the 'overflow' hypothesis is often proposed (Underwood and Paterson, 2003;Stal, 2009), it was never clearly proven. A few studies have shown a positive relationship between light intensity and EPS production (Underwood, 2002;Wolfstein and Stal, 2002) but other studies have reported a negative relation with light intensity and no relationship with nutrient limitation (Perkins et al, 2001;Hanlon et al, 2006). To date there is no information on EPS production in different benthic diatom growth forms, and only EPL species have been compared (Underwood and Paterson, 2003), showing no clear relationship between light response and EPS secretion.…”

Effect of bacteria on growth and biochemical composition of two benthic diatoms Halamphora coffeaeformis and Entomoneis paludosa

“…A photoperiod of 14:10 light: dark was applied with a light intensity of 90 µmol photon m -2 s -1 using cool light fluorescent lamp (Lumix day light, L30W/865, Osram). The microalgae stock-cultures were maintained in exponential growth phase by transferring weekly into fresh medium made of autoclaved artificial seawater (ASW) enriched with nutrients as described in Wolfstein and Stal (2002) but with a F/2 vitamins solution (Guillard, 1975;Guillard and Ryther, 1962).…”