Aerosol inputs affect the optical signatures of dissolved organic matter in NW Mediterranean coastal waters

Sánchez-Pérez, Elvia D.; Marín, Isabel; Nunes, Sdena; Aparicio, Francisco Luis; Fernández‐González, Laura; Peters, Francesc; Pujo‐Pay, Mireille; Conan, Pascal; Marrasé, Cèlia

doi:10.3989/scimar.04318.20b

Cited by 15 publications

(10 citation statements)

References 55 publications

(60 reference statements)

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“…Aerosols, especially of A origin, are also a source of OC ( Viana et al, 2005 ; Pateraki et al, 2012 ), as reflected in the increase in humic-like and protein-like substances ( Supplementary Figure S1 ). However, these compounds may be of recalcitrant nature, as bacteria did not take them up through the incubation time ( Sánchez-Pérez et al, 2016 ). More specifically, the enhancement of β-Gl suggests that A particles may be a source of carbohydrates.…”

Section: Discussionmentioning

confidence: 99%

Coastal Bacterioplankton Metabolism Is Stimulated Stronger by Anthropogenic Aerosols than Saharan Dust

et al. 2017

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In oligotrophic regions, such as the Mediterranean Sea, atmospheric deposition has the potential to stimulate heterotrophic prokaryote growth and production in surface waters, especially during the summer stratification period. Previous studies focused on the role of leaching nutrients from mineral particles of Saharan (S) origin, and were restricted to single locations at given times of the year. In this study, we evaluate the effect of atmospheric particles from diverse sources and with a markedly different chemical composition [S dust and anthropogenic (A) aerosols] on marine planktonic communities from three locations of the northwestern Mediterranean with contrasted anthropogenic footprint. Experiments were also carried out at different times of the year, considering diverse initial conditions. We followed the dynamics of the heterotrophic community and a range of biogeochemical and physiological parameters in six experiments. While the effect of aerosols on bacterial abundance was overall low, bacterial heterotrophic production was up to 3.3 and 2.1 times higher in the samples amended with A and S aerosols, respectively, than in the controls. Extracellular enzymatic activities [leu-aminopeptidase (AMA) and β-glucosidase (β-Gl)] were also enhanced with aerosols, especially from A origin. AMA and β-Gl increased up to 7.1 in the samples amended with A aerosols, and up to 1.7 and 2.1 times, respectively, with S dust. The larger stimulation observed with A aerosols might be attributed to their higher content in nitrate. However, the response was variable depending the initial status of the seawater. In addition, we found that both A and S aerosols stimulated bacterial abundance and metabolism significantly more in the absence of competitors and predators.

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Section: Discussionmentioning

confidence: 99%

Coastal Bacterioplankton Metabolism Is Stimulated Stronger by Anthropogenic Aerosols than Saharan Dust

et al. 2017

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“…Marine DOM can be autochthonous (as, for example, the by-products of marine organisms metabolism derived from phytoplankton and macroalgal extracellular release, cell lysis or particulate organic matter dissolution into DOM; Romera-Castillo et al, 2011b;Wada et al, 2015;Turner, 2015), or allochthonous (mainly from terrestrial origin, as for example leachates from terrestrial plants, wetland drainage and aerosol deposition; Coble, 2007;Murphy et al, 2008;Pey et al, 2010;Sánchez-Pérez et al, 2016), which includes a high diversity of molecular compounds of varying lability. The study of the DOM distribution and transformations in marine systems, along with its role in the carbon cycle, has been in the spotlight during the last two decades because it constitutes one of the greatest reservoirs of organic carbon on Earth (Hansell et al, 2009).…”

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confidence: 99%

“…The more recalcitrant a compound is, the more difficult it is to be remineralized by organisms (Hansell et al, 2009), facilitating its accumulation and trapping CO 2 on its organic form in the ocean for long time scales (Chen and Bada, 1994;Jiao et al, 2010). The presence of fluorescent humic-like material in marine coastal systems has been related mainly to allochthonous inputs (Nieto-Cid et al, 2005;Romera-Castillo et al, 2011a;Sánchez-Pérez et al, 2016), but also to microbial respiration processes (Nieto-Cid et al, 2006;Romera-Castillo et al, 2010). In 2014, Organelli et al also identified DOM from heterotrophic bacteria at the oceanic BOUSSOLE site (Ligurian Sea).…”

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confidence: 99%

Wind-induced changes in the dynamics of fluorescent organic matter in the coastal NW Mediterranean

Aparicio

Nieto‐Cid

Calvo

et al. 2017

Science of The Total Environment

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Marine biogeochemistry dynamics in coastal marine areas is strongly influenced by episodic events such as rain, intense winds, river discharges and anthropogenic activities. We evaluated in this study the importance of these forcing events on modulating seasonal changes in the marine biogeochemistry of the northwestern coast of the Mediterranean Sea, based on data gathered from a fixed coastal sampling station in the area. A 4-year (2011-2014) monthly sampling at four depths (0.5m, 20m, 50m and 80m) was performed to examine the time variability of several oceanographic variables: seawater temperature, salinity, inorganic nutrient concentrations (NO, PO and SiO), chlorophyll a (Chl a), dissolved organic carbon (DOC) and fluorescent dissolved organic matter (FDOM). FDOM dynamics was predominantly influenced by upwelling events and mixing processes, driven by strong and characteristic wind episodes. SW wind episodes favored the upwelling of deeper and denser waters into the shallower shelf, providing a surplus of autochthonous humic-like material and inorganic nutrients, whereas northerlies favored the homogenization of the whole shelf water column by cooling and evaporation. These different wind-induced processes (deep water intrusion or mixing), reported along the four sampled years, determined a high interannual environmental variability in comparison with other Mediterranean sampling sites.

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“…This is most likely due to the high DOC concentrations in surface waters during summer observed at our study site (Laghdass et al, 2010). The accumulation of DOC in stratified surface waters during summer is a recurrent phenomenon reported for Mediterranean waters (Avril, 2002, Romera-Castillo et al, 2010, Sánchez-Pérez et al, 2016 and other oligotrophic oceans (for BATS- (Carlson et al, 2002); for HOTS- (Mopper and Schultz, 1993)). Inorganic nutrient limitation of heterotrophic microbes has been suggested as the underlying mechanism for the observed build-up of DOC in stratified surface waters (Thingstad and Rassoulzadegan, 1999).…”

Section: Resultsmentioning

confidence: 49%

Seasonal freshening of NW Mediterranean surface water impacts microbial heterotrophic activity and dissolved organic matter

Gonzalez

Blain

Obernosterer

2019

Estuarine, Coastal and Shelf Science

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The Rhone river represents the most important source of freshwater, nutrients and organic matter to the northwestern (NW) Mediterranean Sea and riverine input markedly affects biogeochemistry and ecosystem functioning in the estuarine and coastal zone. Structures of low salinity waters (LSW) originating near the river plume can also be transported along the continental shelf and offshore. The objective of the present study was to investigate the influence of LSW distant from their source, focusing on dissolved organic matter (DOM) and related microbial processes during two annual cycles (2007 and 2008) at a time series site characterized by the regular occurrence of LSW in spring (Microbial Observatory Laboratoire Arago). We observed enhanced bacterial heterotrophic production and community respiration and specific DOM features within these LSW, concurrently with low net community production. Our results suggest that LSW represent a mechanism of labile DOM supply, thereby sustaining enhanced heterotrophic microbial metabolism.

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Aerosol inputs affect the optical signatures of dissolved organic matter in NW Mediterranean coastal waters

Cited by 15 publications

References 55 publications

Coastal Bacterioplankton Metabolism Is Stimulated Stronger by Anthropogenic Aerosols than Saharan Dust

Coastal Bacterioplankton Metabolism Is Stimulated Stronger by Anthropogenic Aerosols than Saharan Dust

Wind-induced changes in the dynamics of fluorescent organic matter in the coastal NW Mediterranean

Seasonal freshening of NW Mediterranean surface water impacts microbial heterotrophic activity and dissolved organic matter

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