DMSP and DMS dynamics during a mesoscale iron fertilization experiment in the Northeast Pacific—Part I: Temporal and vertical distributions

Levasseur, Maurice; Scarratt, Michael; Michaud, Sonia; Merzouk, Anissa; Wong, C. S.; Arychuk, Michael; Richardson, W.; Rivkin, Richard B.; Hale, Michelle S.; Wong, Emmy M. Y.; Marchetti, Adrian; Kiyosawa, Hiroshi

doi:10.1016/j.dsr2.2006.05.023

Cited by 62 publications

(51 citation statements)

References 29 publications

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“…While in situ DMS is accurately estimated by DMS SAT in February and June, the variable DMS peak occurring around August is strongly underestimated. Previous studies emphasized the role of iron limitation at OSP, which configures phytoplankton communities dominated by high DMSP taxa (Asher et al, 2017;Levasseur et al, 2006;Royer et al, 2010;Steiner et al, 2012). Interestingly, DMSPt SAT peaks in August at OSP, in phase with the in situ DMS peak and in good accordance with the few available DMSPt measurements (Fig.…”

Section: Unknown Sources Of Error: How Far Can We Go With Remote Senssupporting

confidence: 68%

“…4.2 we speculate about potential causes behind high DMS / DMSPt ratios in late summer and early fall. This exercise shows our limited capacity to account for relevant biogeochemical pro- (Asher et al, 2017;Levasseur et al, 2006;Royer et al, 2010). BATS data are comprised of the monthly 2005-2008 time series (Levine et al, 2016) and cruise data from the vicinity of BATS station in July 2004 (Bailey et al, 2008;Gabric et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

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Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Galí¹,

Levasseur²,

Devred

et al. 2018

Biogeosciences

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117

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Abstract. The marine biogenic gas dimethylsulfide (DMS) modulates climate by enhancing aerosol light scattering and seeding cloud formation. However, the lack of time-and space-resolved estimates of DMS concentration and emission hampers the assessment of its climatic effects. Here we present DMS SAT , a new remote sensing algorithm that relies on macroecological relationships between DMS, its phytoplanktonic precursor dimethylsulfoniopropionate (DMSPt) and plankton light exposure. In the first step, planktonic DMSPt is estimated from satellite-retrieved chlorophyll a and the light penetration regime as described in a previous study . In the second step, DMS is estimated as a function of DMSPt and photosynthetically available radiation (PAR) at the sea surface with an equation of the form: log 10 DMS = α+βlog 10 DMSPt+γ PAR. The two-step DMS SAT algorithm is computationally light and can be optimized for global and regional scales. Validation at the global scale indicates that DMS SAT has better skill than previous algorithms and reproduces the main climatological features of DMS seasonality across contrasting biomes. The main shortcomings of the global-scale optimized algorithm are related to (i) regional biases in remotely sensed chlorophyll (which cause underestimation of DMS in the Southern Ocean) and (ii) the inability to reproduce high DMS / DMSPt ratios in late summer and fall in specific regions (which suggests the need to account for additional DMS drivers). Our work also highlights the shortcomings of interpolated DMS climatologies, caused by sparse and biased in situ sampling. Time series derived from MODIS-Aqua in the subpolar North Atlantic between 2003 and 2016 show wide interannual variability in the magnitude and timing of the annual DMS peak(s), demonstrating the need to move beyond the classical climatological view. By providing synoptic time series of DMS emission, DMS SAT can leverage atmospheric chemistry and climate models and advance our understanding of plankton-aerosol-cloud interactions in the context of global change.

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Section: Unknown Sources Of Error: How Far Can We Go With Remote Senssupporting

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Galí¹,

Levasseur²,

Devred

et al. 2018

Biogeosciences

Self Cite

117

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“…Field observations at OSP in September 2008 show that most major phytoplankton groups were stimulated by the ash deposition, with the diatoms presenting an exceptionally high contribution to the community relative to previous years (Steiner et al 2012). During the large-scale Fe-enrichment experiment Subarctic Ecosystem Response to Iron Enrichment Study (SERIES), the addition of Fe resulted in a rapid (2-3 d) increase in the abundance of cyanobacteria and haptophytes (mostly Emiliania huxleyi) that was followed by a diatom bloom that took place , 10 d after the fertilization (Levasseur et al 2006;Marchetti et al 2006b). The growth of all five groups in our study suggests that these groups were also stimulated shortly after the natural ash fertilization event of 2008.…”

Section: Discussionmentioning

confidence: 99%

Early response of the northeast subarctic Pacific plankton assemblage to volcanic ash fertilization

Melancon

Levasseur

Lizotte

et al. 2014

Limnology & Oceanography

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Fe-poor water collected at Sta. P20 in the Gulf of Alaska in June 2011 was enriched with different concentrations of volcanic ash (0.12, 1.2, and 10 mg L 21 ) from two subduction zone volcanoes, Kasatochi and Chaiten, and incubated onboard under in situ conditions for 6 d. The experimental setup also included a control (no addition) and a positive control (addition of 0.6 nmol L 21 FeSO 4 ). Following a 4 d lag period, there were increases in carbon fixation rates (up to a factor of 10) and chlorophyll a concentrations (up to a factor of 3) in the positive control and in the ash-enriched (1.2 and 10 mg L 21 ) treatments. Diatoms dominated at the end of the incubations, but cyanobacteria, dinoflagellates, pelagophytes, and haptophytes were also stimulated by the presence of ash. Deposition of , 1 mg ash L 21 , which is in the lower range of those estimated to have caused the August 2008 bloom following the eruption of the Kasatochi volcano in the Aleutian Islands, would suffice to trigger a bloom in the Gulf of Alaska.

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“…Measurements made at Ocean Station Papa by the SERIES researchers in the days prior to the iron fertilization revealed high levels of DMS in the surface water (up to 15 nmol L −1 ) (Levasseur et al, 2006). After the fertilization, DMS concentrations in the unfertilized waters surrounding the patch peaked at 27 nmol L −1 on day 10, a natural increase coinciding with a period of lower wind speeds and high irradiance resulting in a shallow wind mixed layer (Levasseur et al, 2006).…”

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confidence: 99%

Contributions from DMS and ship emissions to CCN observed over the summertime North Pacific

et al. 2010

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Abstract. Measurements of cloud condensation nuclei (CCN) made over the North Pacific Ocean in July 2002 are analysed with concurrent measurements of aerosol number, mass and composition. Overall the CCN are controlled by the sulphate, including one case that suggests particle nucleation and growth resulting from dimethyl sulphide oxidation that enhanced CCN concentrations. Hourly CCN concentrations are correlated with concentrations of sulphate plus methanesulphonic acid (MSA) over the entire study period (r 2 =0.43 and 0.52 for supersaturations of 0.34% and 0.19%, respectively), and are not well correlated with other organics (r 2 <0.2). One case study reveals elevated mass and number concentrations of ultrafine and fine organic particles due to regional ship emissions, identified through quadrupole aerosol mass spectrometer (Q-AMS) measurements, during which organic mass concentrations are correlated with CCN values (r 2 =0.39 and 0.46 for supersaturations of 0.19% and 0.34%, respectively). The evolution of the time series and mass distributions of organics, sulphate and MSA over this timeframe indicate that the regional distribution of small, diffuse ship-sourced organic particles act as condensation sites for sulphur species, resulting in a subsequent increase in number concentrations of CCN. We conclude that, where present, direct emissions of anthropogenic organic particles may exert a strong control on marine CCN concentrations once diffused into the marine atmosphere, by acting as condensation sites for biogenic and anthropogenic sulphur species.

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DMSP and DMS dynamics during a mesoscale iron fertilization experiment in the Northeast Pacific—Part I: Temporal and vertical distributions

Cited by 62 publications

References 29 publications

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Sea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scales

Early response of the northeast subarctic Pacific plankton assemblage to volcanic ash fertilization

Contributions from DMS and ship emissions to CCN observed over the summertime North Pacific

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