TY  - JOUR
A1  - Spijkerman, Elly
A1  - Behrend, Hella
A1  - Fach, Bettina
A1  - Gaedke, Ursula
T1  - Decreased phosphorus incorporation explains the negative effect of high iron concentrations in the green microalga Chlamydomonas acidophila
JF  - The science of the total environment : an international journal for scientific research into the environment and its relationship with man
N2  - The green microalga Chlamydomonas acidophila is an important primary producer in very acidic lakes (pH 2.0-3.5), characterized by high concentrations of ferric iron (up to 1 g total Fe L-1) and low rates of primary production. It was previously suggested that these high iron concentrations result in high iron accumulation and inhibit photosynthesis in C. acidophila. To test this, the alga was grown in sterilized lake water and in medium with varying total iron concentrations under limiting and sufficient inorganic phosphorus (Pi) supply, because Pi is an important growth limiting nutrient in acidic waters. Photosynthesis and growth of C. acidophila as measured over 5 days were largely unaffected by high total iron concentrations and only decreased if free ionic Fe3+ concentrations exceeded 100 mg Fe3+ L-1. Although C. acidophila was relatively rich in iron (up to 5 mmol Fe: mol C), we found no evidence of iron toxicity. In contrast, a concentration of 260 mg total Fe L-1 (i.e. 15 mg free ionic Fe3+ L-1), which is common in many acidic lakes, reduced Pi-incorporation by 50% and will result in Pi-limited photosynthesis. The resulting Pi-limitation present at high iron and Pi concentrations was illustrated by elevated maximum Pi-uptake rates. No direct toxic effects of high iron were found, but unfavourable chemical Pi-speciation reduced growth of the acidophile alga.
KW  - Chlamydomonas
KW  - Ecotoxicology
KW  - Extreme environment
KW  - Iron toxicity
KW  - Phosphate limitation
KW  - Phytoplankton
Y1  - 2018
U6  - https://doi.org/10.1016/j.scitotenv.2018.01.188
SN  - 0048-9697
SN  - 1879-1026
VL  - 626
SP  - 1342
EP  - 1349
PB  - Elsevier
CY  - Amsterdam
ER  -