Estuarine plastisphere as an overlooked source of N2O production

Abstract

Abstract“Plastisphere”, microbial communities colonizing plastic debris, has sparked global concern for marine ecosystems. Microbiome inhabiting this novel human-made niche has been increasingly characterized; however, whether the plastisphere holds crucial roles in biogeochemical cycling remains largely unknown. Here we evaluate the potential of plastisphere in biotic and abiotic denitrification and nitrous oxide (N2O) production in estuaries. Biofilm formation provides anoxic conditions favoring denitrifiers. Comparing with surrounding bulk water, plastisphere exhibits a higher denitrifying activity and N2O production, suggesting an overlooked N2O source. Regardless of plastisphere and bulk water, bacterial and fungal denitrifications are the main regulators for N2O production instead of chemodenitrification. However, the contributions of bacteria and fungi in the plastisphere are different from those in bulk water, indicating a distinct N2O production pattern in the plastisphere. These findings pinpoint plastisphere as a N2O source, and provide insights into roles of the new biotope in biogeochemical cycling in the Anthropocene.

Marine plastics alter the organic matter composition of the air-sea boundary layer, with influences on CO2 exchange: a large-scale analysis method to explore future ocean scenarios

“…By using large scale mesocosms, it was possible to explore daily changes in SML formation and the resulting impact on the underlying water pCO2. This supports a better understanding of localized anoxic or hypoxic zones often observed in estuarine and upwelling areas where the SML plays an essential role in air-sea gas exchange Hepach et al, 2016;Upstill-Goddard, 2006) and where marine plastisphere communities can have direct effect on the concentration of N2O and CO2 (Cornejo-D'Ottone et al, 2020;Su et al, 2022).…”

Denitrification and N2O Emission in Estuarine Sediments in Response to Ocean Acidification: From Process to Mechanism

“…Values of δ 15 N bulk , δ 15 N α ( 14 N– 15 N– 16 O), δ 15 N β ( 15 N– 14 N– 16 O), and δ 18 O of N 2 O were detected using an isotope ratio mass spectrometer (Delta V Plus, Thermo Scientific, USA) coupled with a pre-concentrator system (Precon + Gasbench, Thermo Scientific, USA) (see Supporting Information, S5). δ 15 N bulk , δ 15 N α , δ 15 N β , and δ 18 O were calculated with the following relationships , where 15 N R and 18 O represent the isotope ratios of 15 N R / 14 N R and 18 O/ 16 O, respectively. 15 N α and 15 N β are, respectively, the ratios of 15 N/ 14 N at the center and the peripheral sites of N 2 O.…”

“…Values of δ 15 N bulk , δ 15 N α ( 14 N− 15 N− 16 O), δ 15 N β ( 15 N− 14 N− 16 O), and δ 18 O of N 2 O were detected using an isotope ratio mass spectrometer (Delta V Plus, Thermo Scientific, USA) coupled with a pre-concentrator system (Precon + Gasbench, Thermo Scientific, USA) 30 (see Supporting Information, S5). δ 15 N bulk , δ 15 N α , δ 15 N β , and δ 18 O were calculated with the following relationships 31,32…”

Gross Negligence: Impacts of Microplastics and Plastic Leachates on Phytoplankton Community and Ecosystem Dynamics

“…However, at this stage, the impacts of MP and PL on primary productivity is difficult to quantify due to differences in methods used and the diversity of algal responses. Several studies suggest an increase in net community oxygen production and thus primary production in the plastisphere. ,, Yet, this might occur at the cost of diversity in species and biogeochemical cycling, which eventually alter ecosystem productivity ,, (Figure ).…”

“…158,172 The plastisphere also serves as hotspots of greenhouse gases (GHG) cycling and CO 2 and N 2 O consumption and production. 146,173 Although the role of plastisphere photoautotrophs is not consistent across samples, some of the phycosphere bacteria hold prominent roles in GHG cycling. Methane and ethylene are also known to be produced from plastics, especially aged plastics, although the observed impacts are highly local, and the global impacts are insignificant for methane at present emission rates, but emission rates for other hydrocarbons have global relevance.…”