Carbon monoxide emissions by phytoplankton: evidence from laboratory experiments

Environmental context. Carbon monoxide (CO) is a key component for atmospheric chemistry and its production in the ocean, although minor at the global scale, could play a significant role in the remote marine atmosphere. Up to now, CO production in the ocean was considered to mainly originate from the photo-production of dissolved organic matter (mainly under UV radiation). In this paper, we show evidence for direct production of CO by phytoplankton and we suggest it as a significant mechanism for CO production in the ocean. Abstract. In order to investigate carbon monoxide (CO) emissions by phytoplankton organisms, a series of laboratory experiments was conducted in Kiel (Germany). Nine monocultures, including diatoms, coccolithophorids, chlorophytes and cyanobacteria have been characterised. This was done by following the CO variations from monoculture aliquots exposed to photosynthetically active radiation during one or two complete diurnal cycles. All the studied cultures have shown significant CO production when illuminated. Emission rates have been estimated to range from 1.4 × 10–5 to 8.7 × 10–4 μg of CO μg chlorophyll–1 h–1 depending on the species. When considering the magnitude of the emission rates from the largest CO emitters (cyanobacteria and diatoms), this biotic source could represent up to 20% of the CO produced in oceanic waters. As global models currently mainly consider CO production from the photo-degradation of dissolved organic matter, this study suggests that biotic CO production should also be taken into account. Whether this biological production might also contribute to some degree to the previous observed non-zero CO production below the euphotic zone (dark CO production) cannot be deduced here and needs to be further investigated.

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Photochemical production of ammonium in the oligotrophic Cyprus Gyre (Eastern Mediterranean)

Biogeosciences Discussions ◽

10.5194/bgd-3-449-2006 ◽

2006 ◽

Vol 3 (3) ◽

pp. 449-474

Author(s):

V. Kitidis ◽

G. Uher ◽

R. C. Upstill-Goddard ◽

R. F. C. Mantoura ◽

G. Spyres ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Significant Contribution ◽

Eastern Mediterranean ◽

Light Attenuation ◽

Euphotic Zone ◽

Surface Mixed Layer ◽

New Production ◽

Light Absorbance ◽

Local Noon

Abstract. We investigated the photoproduction of ammonium (NH4+) in surface waters of the Cyprus gyre in the central Eastern Mediterranean in May 2002, in 8 on deck irradiations with freshly collected, filtered samples. NH4+ photoproduction (photoammonification) increased with time-integrated irradiance during the course of irradiations. Photoammonification rates around local noon were 0.4–2.9 nmol L−1 h−1. Normalised to time integrated irradiance, these rates were 0.9–3.8 pmol L−1 h−1/(W m−2) and were significantly correlated with Chromophoric Dissolved Organic Matter (CDOM) absorbance at 300 nm normalised to Dissolved Organic Carbon (DOC). These results are consistent with the notion that successive CDOM photobleaching in the surface mixed layer results in decreased DOC-normalised light absorbance concurrent with decreased dissolved organic matter reactivity with regard to photochemical NH4+ release. Combining our experimental data with estimates of annual solar irradiance and water column light attenuation yields an annual photoammonification rate for the Cyprus Gyre of 40±17 mmol m−2 a−1, equivalent to ~12±5% of the previously estimated annual nitrogen requirement of new production in this region. Based on this analysis, NH4+ photoproduction makes a small, but significant contribution to the nitrogen budget of the euphotic zone in the oligotrophic Cyprus Gyre.

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Photochemical production of ammonium in the oligotrophic Cyprus Gyre (Eastern Mediterranean)

Biogeosciences ◽

10.5194/bg-3-439-2006 ◽

2006 ◽

Vol 3 (4) ◽

pp. 439-449 ◽

Cited By ~ 18

Author(s):

V. Kitidis ◽

G. Uher ◽

R. C. Upstill-Goddard ◽

R. F. C. Mantoura ◽

G. Spyres ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Eastern Mediterranean ◽

Light Attenuation ◽

Euphotic Zone ◽

N Deposition ◽

Surface Mixed Layer ◽

Atmospheric N Deposition ◽

New Production ◽

Order Of Magnitude

Abstract. We investigated the photoproduction of ammonium (NH4+) in surface waters of the Cyprus gyre in the central Eastern Mediterranean in May 2002, in 8 on deck irradiations with freshly collected, filtered samples. NH4+ photoproduction (photoammonification) increased with time-integrated irradiance during the course of irradiations. Photoammonification rates around local noon were 0.4–2.9 nmol L−1 h−1. Normalised to time integrated irradiance, these rates were 0.9–3.8 pmol L−1 h−1/(W m−2) and were significantly correlated with Chromophoric Dissolved Organic Matter (CDOM) absorbance at 300 nm normalised to Dissolved Organic Carbon (DOC). These results are consistent with the notion that successive CDOM photobleaching in the surface mixed layer results in decreased DOC-normalised light absorbance concurrent with decreased dissolved organic matter reactivity with regard to photochemical NH4+ release. Combining our experimental data with estimates of annual solar irradiance and water column light attenuation yields an annual photoammonification rate for the Cyprus Gyre of 40±17 mmol m−2 a−1, equivalent to ~12±5% of the previously estimated annual nitrogen requirement of new production and in the same order of magnitude as atmospheric N deposition in this region. Based on this analysis, NH4+ photoproduction makes a small, but significant contribution to the nitrogen budget of the euphotic zone in the oligotrophic Cyprus Gyre.

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Effect of UV and Visible Radiation on Optical Properties of Chromophoric Dissolved Organic Matter Released by Emiliania huxleyi

Journal of Marine Science and Engineering ◽

10.3390/jmse8110888 ◽

2020 ◽

Vol 8 (11) ◽

pp. 888

Author(s):

Simona Retelletti Brogi ◽

Bruno Charrière ◽

Margherita Gonnelli ◽

Frédéric Vaultier ◽

Richard Sempéré ◽

...

Keyword(s):

Organic Matter ◽

Optical Properties ◽

Dissolved Organic Matter ◽

Linear Trend ◽

Euphotic Zone ◽

Emiliania Huxleyi ◽

Visible Radiation ◽

Irradiation Energy ◽

Before And After

Photodegradation is a natural process that strongly affects the chromophoric fraction of dissolved organic matter (DOM), especially in surface water of the oceans. In the euphotic zone, the concentration and quality of DOM are mostly dependent on primary production by phytoplankton. The effect of photodegradation on algal DOM has not been investigated as much as on terrestrial DOM. In this study, we explored the effect of different spectral regions (i.e., full sun spectrum, visible light, 295–800 nm, 305–800 nm, and 320–800 nm) on algal exudates by Emiliania huxleyi, a ubiquitous coccolithophore. The optical properties (absorption and fluorescence) of algal DOM were investigated before and after irradiation with the different spectral regions. The absorption and fluorescence spectra were compared before and after irradiation. The results showed an increase in the effect of photobleaching with increasing irradiation energy for all of the absorbance indices. Similarly, the protein-like fluorescence decreased at increasing irradiation energy. The humic-like fluorescence, which was the most affected, did not show a linear trend between photobleaching and irradiation energy, which suggested that irradiation mainly determined a change in these molecules’ quantum yield.

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Carbon Monoxide Photoproduction: Implications for Photoreactivity of Arctic Permafrost-Derived Soil Dissolved Organic Matter

Environmental Science & Technology ◽

10.1021/es502057n ◽

2014 ◽

Vol 48 (16) ◽

pp. 9113-9121 ◽

Cited By ~ 16

Author(s):

Jun Hong ◽

Huixiang Xie ◽

Laodong Guo ◽

Guisheng Song

Keyword(s):

Carbon Monoxide ◽

Organic Matter ◽

Dissolved Organic Matter

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Spectrally resolved efficiencies of carbon monoxide (CO) photoproduction in the western Canadian Arctic: particles versus solutes

Biogeosciences ◽

10.5194/bg-10-3731-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 3731-3748 ◽

Cited By ~ 14

Author(s):

G. Song ◽

H. Xie ◽

S. Bélanger ◽

E. Leymarie ◽

M. Babin

Keyword(s):

Carbon Monoxide ◽

Organic Matter ◽

Particulate Matter ◽

Visible Light ◽

Euphotic Zone ◽

Apparent Quantum Yield ◽

Mineral Absorption ◽

Visible Light Driven ◽

Spectrally Resolved ◽

First Time

Abstract. Spectrally resolved efficiency (i.e. apparent quantum yield, AQY) of carbon monoxide (CO) photoproduction is a useful indicator of substrate photoreactivity and a crucial parameter for modeling CO photoproduction rates in the water column. Recent evidence has suggested that CO photoproduction from particles in marine waters is significant compared to the well-known CO production from chromophoric dissolved organic matter (CDOM) photodegradation. Although CDOM-based CO AQY spectra have been extensively determined, little is known of this information on the particulate phase. Using water samples collected from the Mackenzie estuary, shelf, and Canada Basin in the southeastern Beaufort Sea, the present study for the first time quantified the AQY spectra of particle-based CO photoproduction and compared them with the concomitantly determined CDOM-based CO AQY spectra. CO AQYs of both particles and CDOM decreased with wavelength but the spectral shape of the particulate AQY was flatter in the visible regime. This feature resulted in a disproportionally higher visible light-driven CO production by particles, thereby increasing the ratio of particle- to CDOM-based CO photoproduction with depth in the euphotic zone. In terms of depth-integrated production in the euphotic zone, CO formation from CDOM was dominated by the ultraviolet (UV, 290–400 nm) radiation whereas UV and visible light played roughly equal roles in CO production from particles. Spatially, CO AQY of bulk particulate matter (i.e. the sum of organics and inorganics) augmented from the estuary and shelf to the basin while CO AQY of CDOM trended inversely. Water from the deep chlorophyll maximum layer revealed higher CO AQYs than did surface water for both particles and CDOM. CO AQY of bulk particulate matter exceeded that of CDOM on the shelf and in the basin, but the sequence reversed in the estuary. Without consideration of the potential role of metal oxides (e.g. iron oxides) in particle photochemistry, mineral absorption-corrected CO AQY of particulate organic matter (POM) could, however, surpass its CDOM counterpart in all three sub-regions and displayed magnitudes in the estuary that overtook those in shelf and offshore waters. In terms of CO photoproduction, POM was thus more photoreactive than CDOM, irrespective of the organic matter's origins (i.e. terrigenous or marine). Riverine CDOM exhibited higher photoreactivity than marine CDOM and land-derived POM appeared more photoreactive than marine POM. AQY-based modeling indicates that CO photoproduction in the study area is underestimated by 12–32% if the particulate term is ignored.

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Global-scale combustion sources of organic aerosols: sensitivity to formation and removal mechanisms

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-7345-2017 ◽

2017 ◽

Vol 17 (12) ◽

pp. 7345-7364 ◽

Cited By ~ 11

Author(s):

Alexandra P. Tsimpidi ◽

Vlassis A. Karydis ◽

Spyros N. Pandis ◽

Jos Lelieveld

Keyword(s):

Organic Compounds ◽

Atmospheric Chemistry ◽

Climate Model ◽

Hybrid Approach ◽

Model Performance ◽

Organic Aerosols ◽

Global Scale ◽

Emission Rates ◽

Combustion Sources ◽

Scavenging Efficiency

Abstract. Organic compounds from combustion sources such as biomass burning and fossil fuel use are major contributors to the global atmospheric load of aerosols. We analyzed the sensitivity of model-predicted global-scale organic aerosols (OA) to parameters that control primary emissions, photochemical aging, and the scavenging efficiency of organic vapors. We used a computationally efficient module for the description of OA composition and evolution in the atmosphere (ORACLE) of the global chemistry–climate model EMAC (ECHAM/MESSy Atmospheric Chemistry). A global dataset of aerosol mass spectrometer (AMS) measurements was used to evaluate simulated primary (POA) and secondary (SOA) OA concentrations. Model results are sensitive to the emission rates of intermediate-volatility organic compounds (IVOCs) and POA. Assuming enhanced reactivity of semi-volatile organic compounds (SVOCs) and IVOCs with OH substantially improved the model performance for SOA. The use of a hybrid approach for the parameterization of the aging of IVOCs had a small effect on predicted SOA levels. The model performance improved by assuming that freshly emitted organic compounds are relatively hydrophobic and become increasingly hygroscopic due to oxidation.

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Two databases derived from BGC-Argo float measurements for biogeochemical and bio-optical applications at the global scale

10.5194/essd-2017-58 ◽

2017 ◽

Author(s):

Emanuele Organelli ◽

Marie Barbieux ◽

Hervé Claustre ◽

Catherine Schmechtig ◽

Antoine Poteau ◽

...

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Optical Depth ◽

Open Data ◽

Temporal Distribution ◽

Global Scale ◽

Vertical Profiles ◽

Photosynthetically Available Radiation ◽

Global Database ◽

Fluorescent Dissolved Organic Matter

Abstract. Since 2012, an array of 105 Biogeochemical (BGC) Argo floats has been deployed across the world’s oceans to fill the observational gap characterizing most of open-ocean environments. Profiles of biogeochemical (chlorophyll and fluorescent dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradiance at three wavelengths and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The global database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically-developed procedures and its time-series is quality-assessed to identify issues related to biofouling and/or instrumental drift. A second database of 5748 profile-derived products within the first optical depth (i.e. the layer of interest for satellite remote sensing) is also presented and its spatio-temporal distribution discussed. This database, devoted to field and remote ocean color applications, includes diffuse attenuation coefficients for downward irradiance at three narrow wavebands and one broad waveband (photosynthetically available radiation), calibrated chlorophyll and dissolved organic matter fluorescence, and single-wavelength particulate optical backscattering. To demonstrate the applicability of these global databases, data within the first optical depth are finally compared with previously established bio-optical models and used to validate remotely-derived bio-optical products. The quality-controlled databases are publicly available from SEANOE (SEA scieNtific Open data Edition) publisher at http://doi.org/10.17882/49388 and http://doi.org/10.17882/47142 for vertical profiles and products within the first optical depth, respectively.

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