Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms

Piatka D, Frank A, Köhler I, Castiglione K, van Geldern R, Barth J (2021)


Publication Type: Journal article

Publication year: 2021

Journal

Article Number: 151067

DOI: 10.1016/j.scitotenv.2021.151067

Abstract

Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over a period of 23 months. This helped to map turnover and sources of aqueous carbon before, during, and after bloom events. During bloom events POC isotope values (δ13CPOC) increased up to −17.4‰, after aqueous CO2 (CO2(aq)) fell below an atmospheric equilibration value of 412 μatm. Additionally, carbon isotope enrichment between CO2(aq) and POC (εCO2-phyto) ranged from 2.0 to 21.5‰ with lowest fractionations observed at pH values above 8.9. The increase of δ13CPOC and decrease of εCO2-phyto values at low pCO2 and high pH was most likely caused by the activation of the carbon concentrating mechanism (CCM). This mechanism correlated with prevalent assimilation of 13C-enriched HCO3. Surprisingly, CO2(aq) still contributed more than 50% to the POC pool down to pCO2 values of around 150 μatm. Only after this threshold the reduced εCO2-phyto suggested incorporation of 13C-enriched HCO3.

Authors with CRIS profile

How to cite

APA:

Piatka, D., Frank, A., Köhler, I., Castiglione, K., van Geldern, R., & Barth, J. (2021). Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms. Science of the Total Environment. https://dx.doi.org/10.1016/j.scitotenv.2021.151067

MLA:

Piatka, David, et al. "Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms." Science of the Total Environment (2021).

BibTeX: Download