Abstract
Aquatic ecosystems are composed by a myriad of dissolved organic materials that can be assimilated by microalgae, while they can perform photosynthesis, this is refereed as mixotrophy. However, ecotoxicological tests usually consider only the photoautotrophic metabolism. This research investigated the ecotoxicological differences between photoautotrophy and mixotrophy in Chlorella sorokiniana exposed to cadmium (Cd). Chlorophyll a, photosynthetic efficiency (Fv/Fm), cell viability, biochemical composition and pH were used to monitor possible toxic effects at 72 h cultures. Glucose (1 g.L-1) was used as organic carbon source. To evaluate the probability of the photoautotrophic culture being more affected by Cc than the mixotrophic one, Bayesian statistical analysis was performed. The photoautotrophic cultures were more affected by Cd than the mixotrophic ones, with reduction of all evaluated parameters, excep for protein concentration. However, in mixotrophic cultures, no changes in protein concentration and proteins:carbohydrates ratio were observed, and chlorophyll a, Fv/Fm and cell viability were only affected at the high Cd concentrations (range In -11.5 to -9.4). However, both mixotrophy and photoautotrophy had the same probability of having the carbohydrates concentration affected by Cd. We conclude that the microalgae in mixotrophy were more resistant to the Cd than in photoautotrophy. In addition, we showed that under photoautotrophy Fv/Fm decreased linearly as Cd concentration increased, but in mixotrophy no effect was observed up to 10-5 molL(-1) Cd, after which it decreased. We rationale that the reduced photosynthetic capacity under mixotrophy can end up reducing the release of oxygen gas, which can compromise the entire aquatic ecosystem. (C) 2018 Elsevier Ltd. All rights reserved
| Original language | English |
|---|---|
| Pages (from-to) | 794-803 |
| Number of pages | 10 |
| Journal | Chemosphere |
| Volume | 211 |
| DOIs | |
| Publication status | Published - Nov 2018 |
| Externally published | Yes |
Cite this
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An investigation onto Cd toxicity to freshwater microalga Chlorella sorokiniana in mixotrophy and photoautotrophy : A Bayesian approach. / Marchello, Adriano Evandir; Oliveira, Natalia Lombardi; Lombardi, Ana Teresa; Polpo, Adriano.
In: Chemosphere, Vol. 211, 11.2018, p. 794-803.Research output: Contribution to journal › Article
TY - JOUR
T1 - An investigation onto Cd toxicity to freshwater microalga Chlorella sorokiniana in mixotrophy and photoautotrophy
T2 - A Bayesian approach
AU - Marchello, Adriano Evandir
AU - Oliveira, Natalia Lombardi
AU - Lombardi, Ana Teresa
AU - Polpo, Adriano
PY - 2018/11
Y1 - 2018/11
N2 - Aquatic ecosystems are composed by a myriad of dissolved organic materials that can be assimilated by microalgae, while they can perform photosynthesis, this is refereed as mixotrophy. However, ecotoxicological tests usually consider only the photoautotrophic metabolism. This research investigated the ecotoxicological differences between photoautotrophy and mixotrophy in Chlorella sorokiniana exposed to cadmium (Cd). Chlorophyll a, photosynthetic efficiency (Fv/Fm), cell viability, biochemical composition and pH were used to monitor possible toxic effects at 72 h cultures. Glucose (1 g.L-1) was used as organic carbon source. To evaluate the probability of the photoautotrophic culture being more affected by Cc than the mixotrophic one, Bayesian statistical analysis was performed. The photoautotrophic cultures were more affected by Cd than the mixotrophic ones, with reduction of all evaluated parameters, excep for protein concentration. However, in mixotrophic cultures, no changes in protein concentration and proteins:carbohydrates ratio were observed, and chlorophyll a, Fv/Fm and cell viability were only affected at the high Cd concentrations (range In -11.5 to -9.4). However, both mixotrophy and photoautotrophy had the same probability of having the carbohydrates concentration affected by Cd. We conclude that the microalgae in mixotrophy were more resistant to the Cd than in photoautotrophy. In addition, we showed that under photoautotrophy Fv/Fm decreased linearly as Cd concentration increased, but in mixotrophy no effect was observed up to 10-5 molL(-1) Cd, after which it decreased. We rationale that the reduced photosynthetic capacity under mixotrophy can end up reducing the release of oxygen gas, which can compromise the entire aquatic ecosystem. (C) 2018 Elsevier Ltd. All rights reserved
AB - Aquatic ecosystems are composed by a myriad of dissolved organic materials that can be assimilated by microalgae, while they can perform photosynthesis, this is refereed as mixotrophy. However, ecotoxicological tests usually consider only the photoautotrophic metabolism. This research investigated the ecotoxicological differences between photoautotrophy and mixotrophy in Chlorella sorokiniana exposed to cadmium (Cd). Chlorophyll a, photosynthetic efficiency (Fv/Fm), cell viability, biochemical composition and pH were used to monitor possible toxic effects at 72 h cultures. Glucose (1 g.L-1) was used as organic carbon source. To evaluate the probability of the photoautotrophic culture being more affected by Cc than the mixotrophic one, Bayesian statistical analysis was performed. The photoautotrophic cultures were more affected by Cd than the mixotrophic ones, with reduction of all evaluated parameters, excep for protein concentration. However, in mixotrophic cultures, no changes in protein concentration and proteins:carbohydrates ratio were observed, and chlorophyll a, Fv/Fm and cell viability were only affected at the high Cd concentrations (range In -11.5 to -9.4). However, both mixotrophy and photoautotrophy had the same probability of having the carbohydrates concentration affected by Cd. We conclude that the microalgae in mixotrophy were more resistant to the Cd than in photoautotrophy. In addition, we showed that under photoautotrophy Fv/Fm decreased linearly as Cd concentration increased, but in mixotrophy no effect was observed up to 10-5 molL(-1) Cd, after which it decreased. We rationale that the reduced photosynthetic capacity under mixotrophy can end up reducing the release of oxygen gas, which can compromise the entire aquatic ecosystem. (C) 2018 Elsevier Ltd. All rights reserved
KW - Mixotrophic
KW - growth
KW - Cd
KW - Glucose
KW - Biochemical composition
KW - PHOTOSYNTHETIC RESPONSES
KW - PHYTOCHELATIN PRODUCTION
KW - NEOCHLORIS-OLEOABUNDANS
KW - CADMIUM
KW - COPPER
KW - GROWTH
KW - ACCUMULATION
KW - VULGARIS
KW - PROTEIN
KW - STRESS
U2 - 10.1016/j.chemosphere.2018.08.019
DO - 10.1016/j.chemosphere.2018.08.019
M3 - Article
VL - 211
SP - 794
EP - 803
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
ER -