The increasing aluminum content affects the growth, cellular chlorophyll a and oxidation stress of cyanobacteria Synechococcus sp. WH7803

Abstract

I n t e r n a t i o n a l J o u r n a l o f O c e a n o g r a p h y a n d H y d r o b i o l o g y AbstractEffects of marine aluminum (Al) on phytoplankton are controversial, making it important to elucidate the mechanisms underlying Al effects. This study was aimed at identifying the effects of Al on the growth, chlorophyll a (chl a) content and the antioxidant mechanism of cyanobacteria Synechococcus sp. WH7803. The growth rate increased from 0.33 to 0.52 d -1 in media with the increasing Al concentration from 0.2 (control) to 20 μmol l -1 and almost saturated to 0.44 d -1 at ~ 0.5 μmol Al l -1 . The higher growth resulted in the higher biomass in both stationary and decay phases in the conditions of higher Al content. Chl a per cell reached 10.19 μg cell -1 in the exponential phase at 20 μmol Al l -1 , approximately 1.6 and 3.1 times higher than those in stationary and decay phases, respectively, and chl a per cell showed a similar pattern as a growth rate when plotted with Al content. Al addition increased the cellular methane dicarboxylic aldehyde (MDA) content in the exponential phase and decreased the superoxide dismutase (SOD) activity in the decay phase. In particular, our results indicated a positive relationship between chl a per cell and the growth rate, suggesting the stimulation of increasing Al on the growth of Synechococcus is related to the enhancement of cellular chl a content.

Aluminum increases net carbon fixation by marine diatoms and decreases their decomposition: Evidence for the iron–aluminum hypothesis

“…The enhanced net carbon fixation by the marine diatoms T. weissflogii, T. pseudonana and T. oceanica in the Al-enriched treatments, compared to the controls, is consistent with previous reports of the beneficial effects of Al on the growth of marine phytoplankton (Shi et al 2015;Zhou et al 2016;Liu et al 2018;Zhou et al 2018a). The previous studies showed that Al enhanced the yield of phytoplankton biomass in terms of cell abundance, total cell volume, photosynthetic pigments (i.e., chlorophyll a) and nitrogen fixation.…”

Aluminum effects on marine phytoplankton: implications for a revised Iron Hypothesis (Iron–Aluminum Hypothesis)

“…Enhanced growth of other marine phytoplankton species (Dunaliella tertiolecta, Tetraselmis sp., and Ceratoneis closterium) in the presence of Al was unexpectedly observed during tests of Al toxicity to marine phytoplankton (Gillmore et al 2016;Golding et al 2015;Saçan et al 2007). Similar stimulatory effects of Al enrichment on marine phytoplankton growth (e.g., Synechococcus sp., Thalassiosira weissflogii and Crocosphaera watsonii) were reported in laboratory studies (Leleyter et al 2016;Liu et al 2018;Shi et al 2015;Shi et al 2016;Zhou et al 2016). Enhanced growth of marine phytoplankton (e.g., Diatoms,…”

“…Aluminum toxicity to marine phytoplankton has only been intentionally tested in 1 recent years (Gillmore et al 2016;Golding et al 2015;Harford et al 2011;Saçan et al 2 2007;Xie et al 2015). The influence of Al on the growth, iron (Fe) uptake and 3 physiology of marine phytoplankton has also been reported in other studies (Liu et al 2018;Santana-Casiano et al 1997;Shi et al 2015;Stoffyn 1979;Vrieling et al 1999;5 Zhou et al 2016). Among all the 13 marine phytoplankton species tested (Table S1), the 6 growth of only one diatom Ceratoneis closterium was reported to be inhibited by 7 environmentally relevant Al concentrations (higher than about 10 µg/L or 0.37 µM) in 8 one study (Golding et al 2015), but its growth was reported to be stimulated by low Al 9 concentrations (< 60 µg/L or < 2.2 µM) in another study (Gillmore et al 2016).…”

Does galvanic cathodic protection by aluminum anodes impact marine organisms?

“…A varying sensitivity for other marine bacteria is to be expected. In this respect, it is interesting that recent studies have shown that aluminum can even have a stimulative effect on the growth of different cyanobacteria [34,35]. Nevertheless, it can be concluded that bacterial toxicity is unlikely to be the main driver for an environmental risk assessment of galvanic anodes because species from other trophic levels showed higher sensitivities.…”