Ultraviolet Radiation Drives Emission of Climate‐Relevant Gases From Marine Phytoplankton

McLeod, Andrew; Brand, Tim; Campbell, Christine; Davidson, Keith; Hatton, Angela D.

doi:10.1029/2021jg006345

Cited by 13 publications

(34 citation statements)

References 112 publications

(239 reference statements)

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“…( 2) Methane is formed by microbes including (a) methanogenic archaea in anoxic microsites (de Angelis & Lee, 1994;Karl & Tilbrook, 1994;Oremland, 1979;Schmale et al, 2018;Stawiarski et al, 2019;Zindler et al, 2013), (b) bacterial degradation of the algal metabolites dimethylsulfonium propionate (DMSP) and its degradation products dimethyl sulfoxide (DMSO) and DMS (Damm et al, 2008(Damm et al, , 2010Florez-Leiva et al, 2013), (c) N 2 -fixing bacteria, carrying Fe-only nitrogenase (Zheng et al, 2018), (d) bacterial conversion of methylamine (Wang et al, 2021) and (e) bacterial degradation of methyl phosphonates (MPn) via the C-P lyase reaction pathway, with MPn serving as an alternative source of P under phosphate-limiting conditions (del Valle & Karl, 2014;Karl et al, 2008;Metcalf et al, 2012;Repeta et al, 2016;Taenzer et al, 2020). (3) Phytoplankton produces CH 4 per se (Bižić, Grossart, & Ionescu, 2020;Ernst et al, 2022;Klintzsch et al, 2019Klintzsch et al, , 2020Lenhart et al, 2016;McLeod et al, 2021), ( 4) and specifically for surface waters of lakes physical transport processes from shallow water zones to the open surface waters (Encinas Fernández et al, 2016;Peeters et al, 2019). For a more detailed overview of the different sources and processes please refer to recent review articles (e.g., Bižić, 2021;Bižić, Klintzsch, et al, 2020;DelSontro et al, 2018;Liu et al, 2022;Reeburgh, 2007;Tang et al, 2016).…”

mentioning

confidence: 99%

Stable Carbon Isotope Signature of Methane Released From Phytoplankton

Klintzsch

Geisinger

Wieland

et al. 2023

Geophysical Research Letters

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Aquatic ecosystems play an important role in global methane cycling and many field studies have reported methane supersaturation in the oxic surface mixed layer (SML) of the ocean and in the epilimnion of lakes. The origin of methane formed under oxic condition is hotly debated and several pathways have recently been offered to explain the “methane paradox.” In this context, stable isotope measurements have been applied to constrain methane sources in supersaturated oxygenated waters. Here we present stable carbon isotope signatures for six widespread marine phytoplankton species, three haptophyte algae and three cyanobacteria, incubated under laboratory conditions. The observed isotopic patterns implicate that methane formed by phytoplankton might be clearly distinguished from methane produced by methanogenic archaea. Comparing results from phytoplankton experiments with isotopic data from field measurements, suggests that algal and cyanobacterial populations may contribute substantially to methane formation observed in the SML of oceans and lakes.

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mentioning

confidence: 99%

Stable Carbon Isotope Signature of Methane Released From Phytoplankton

Klintzsch

Geisinger

Wieland

et al. 2023

Geophysical Research Letters

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“…The basis of the incubation study was a stable isotope approach in which tracer solutions were applied consisting of different concentrations of MPn in the natural isotopic abundance and in the 13 C-labeled form (methylphosphonic acid- 13 C, 99% 13 C, Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany) (Figure 1A). In order to determine concentrations of the MPn and 13 C-MPn on the one hand and concentrations of the formed CH 4 and its stable carbon isotopologues (δ 13 C−CH 4 ) on the other hand, two incubation setups were prepared, K1 and K2, in which the 13 C-label of the tracer solutions was added in concentrations matching the instrumental requirements for the respective analyses (Figure 1B). For gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) measurements, a change in δ 13 C−CH 4 values of one-tenth to several hundred per mille is optimal for reliable tracer detection as well as to avoid linearity problems.…”

Section: Experimental Design and Implementation Of The Incubation Studymentioning

confidence: 99%

Stable Isotope Approach to Assess the Production and Consumption of Methylphosphonate and Its Contribution to Oxic Methane Formation in Surface Waters

Kanwischer,

Klintzsch,

Schmale

2023

Environ. Sci. Technol.

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Recent studies in aquatic environments have indicated that microbial methane production is not limited to strictly anoxic conditions and is widespread in the oxic water column. Based on recent investigations proposing linkage between the microbial turnover of methylphosphonate (MPn) and the widespread methane oversaturation in surface waters, we conducted an MPn/13C-MPn tracer approach that combines liquid chromatography–mass spectrometry and gas chromatography–stable isotope ratio mass spectrometry to assess concentrations of the MPn tracer and its contribution to oxic methane formation. In our study, conducted during summer 2020 in the Baltic Sea, we show that MPn is a potent methanogenic substrate in the surface water. However, we found that MPn was produced within the surface and subthermocline water bodies and that its turnover was not limited to the phosphorus-stressed and cyanobacteria-rich surface water. However, our study revealed that most of the MPn was probably degraded via alternative pathways, not releasing methane. Our assessment indicates that the contribution of the MPn degradation pathway only contributed marginally to oxic methane production at the study site in the Baltic Sea and that a variety of methanogenic pathways are probably responsible for the surface-water methane enrichments.

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“…For terrestrial vegetation, UV light was considered an important environmental factor that controls OMP from the plant components lignin and pectin. However, UV light is strongly attenuated in natural waters depending on water depth (McLeod et al 2021) and the concentration of cDOM (Bricaud et al 1981). The UV‐driven pathway of CH 4 formation might thus be less important in aquatic ecosystems as compared to terrestrial systems ( see above).…”

Section: Potential Of Submerged Macrophytes For Ompmentioning

confidence: 99%

Potential role of submerged macrophytes for oxic methane production in aquatic ecosystems

Hilt

Grossart

Mcginnis

et al. 2022

Limnology & Oceanography

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Methane (CH4) from aquatic ecosystems contributes to about half of total global CH4 emissions to the atmosphere. Until recently, aquatic biogenic CH4 production was exclusively attributed to methanogenic archaea living under anoxic or suboxic conditions in sediments, bottom waters, and wetlands. However, evidence for oxic CH4 production (OMP) in freshwater, brackish, and marine habitats is increasing. Possible sources were found to be driven by various planktonic organisms supporting different OMP mechanisms. Surprisingly, submerged macrophytes have been fully ignored in studies on OMP, yet they are key components of littoral zones of ponds, lakes, and coastal systems. High CH4 concentrations in these zones have been attributed to organic substrate production promoting classic methanogenesis in the absence of oxygen. Here, we review existing studies and argue that, similar to terrestrial plants and phytoplankton, macroalgae and submerged macrophytes may directly or indirectly contribute to CH4 formation in oxic waters. We propose several potential direct and indirect mechanisms: (1) direct production of CH4; (2) production of CH4 precursors and facilitation of their bacterial breakdown or chemical conversion; (3) facilitation of classic methanogenesis; and (4) facilitation of CH4 ebullition. As submerged macrophytes occur in many freshwater and marine habitats, they are important in global carbon budgets and can strongly vary in their abundance due to seasonal and boom‐bust dynamics. Knowledge on their contribution to OMP is therefore essential to gain a better understanding of spatial and temporal dynamics of CH4 emissions and thus to substantially reduce current uncertainties when estimating global CH4 emissions from aquatic ecosystems.

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Ultraviolet Radiation Drives Emission of Climate‐Relevant Gases From Marine Phytoplankton

Abstract: Photochemical emissions to the atmosphere from the marine and freshwater environment have recently received attention for their role and contribution to biogeochemical cycles of carbon (

Cited by 13 publications

References 112 publications

Stable Carbon Isotope Signature of Methane Released From Phytoplankton

Stable Carbon Isotope Signature of Methane Released From Phytoplankton

Stable Isotope Approach to Assess the Production and Consumption of Methylphosphonate and Its Contribution to Oxic Methane Formation in Surface Waters

Potential role of submerged macrophytes for oxic methane production in aquatic ecosystems

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