In:
Frontiers in Microbiology, Frontiers Media SA, Vol. 12 ( 2021-10-6)
Abstract:
Epilithon contributes to phosphorus (P) cycling in lakes, but its P uptake traits have been rarely studied. We measured the chemical composition of epilithon and its inorganic P uptake kinetics using isotope 33 P in three deep oligo- to mesotrophic post-mining lakes in April, July, and October 2019. Over the sampling period, epilithon biomass doubled, while the P content in biomass dropped to 60% of the April values, and the seasonal changes in P content expressed per epilithon area were only marginal and statistically not significant. High epilithic C:P molar ratios (677 on average) suggested strong P deficiency in all investigated lakes. Regarding the kinetic parameters of phosphorus uptake, maximum uptake velocity ( V max , seasonal range 1.9–129 mg P g OM –1 h –1 ) decreased by an order of magnitude from April to October, while half-saturation constant ( K S , seasonal range 3.9–135 mg P L –1 ) did not show any consistent temporal trend. Values of epilithic specific P uptake affinity ( SPUA E , seasonal range 0.08–3.1 L g OM –1 h –1 ) decreased from spring to autumn and were two to four orders of magnitude lower than the corresponding values for seston ( SPUA sest ), which showed an opposite trend. Considering our results, we suggest a possible mechanism underlying a stable coexistence of planktonic and epilithic microorganisms, with plankton prospering mostly in summer and autumn and epilithon in winter and spring season. Additionally, a phenomenon of reversible abiotic P adsorption on epilithon was observed.
Type of Medium:
Online Resource
ISSN:
1664-302X
DOI:
10.3389/fmicb.2021.735498
DOI:
10.3389/fmicb.2021.735498.s001
Language:
Unknown
Publisher:
Frontiers Media SA
Publication Date:
2021
detail.hit.zdb_id:
2587354-4
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