Assessing the role of dust deposition on phytoplankton ecophysiology and succession in a low-nutrient low-chlorophyll ecosystem: a mesocosm experiment in the Mediterranean Sea

Giovagnetti, Vasco; Brunet, Christophe; Conversano, Fabio; Tramontano, F.; Obernosterer, Ingrid; Ridame, Céline; Guieu, Cécile

doi:10.5194/bg-10-2973-2013

Cited by 42 publications

(59 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As with the POC dust fluxes and optical parameters, the phytoplankton community responded dif- ferently to both seedings with a distinct magnitude, timing, and composition change (Giovagnetti et al, 2013). Although optical measurements revealed rapid particulate export following the first seeding (Bressac et al, 2012), c p (0-10 m) continually increased during the T 0 -T 53 period (Fig.…”

Section: The Dynamics and Timing Of Particulate Exportmentioning

confidence: 86%

“…Furthermore, following both seedings, the biomass of siliceous phytoplankton remained very low and a major response was observed for non-siliceous phytoplanktonic organisms (Giovagnetti et al, 2013). Although calcified organisms likely responded to the seedings, the fraction of biogenic CaCO 3 collected in sediment traps of + dust mesocosms remained negligible (3 ± 0.5 % in mass; .…”

Section: A Comparison Between Primary Production Poc and Lithogenicmentioning

confidence: 97%

“…Stratification was higher during the second seeding experiment but interrupted by wind-driven mixing events. Considering the biological response to the first seeding (Giovagnetti et al, 2013;Ridame et al, 2014), the biogeochemical status of the water column changed between the experiments. Prior to the first seeding, the chlorophyll a concentration (Chl a) was characteristic of oligotrophic conditions (0.07 ± 0.02 mg m −3 ).…”

Section: Evolution Of the Physical And Biogeochemical Parametersmentioning

confidence: 99%

“…Both data sets remained significantly different (p values < 0.05) throughout the experiment. The strong stimulation of PP went along with a rapid enhancement of the pigment content per cell and a rapid photoprotective response (Giovagnetti et al, 2013). Therefore, the increase in PP seems to have been favored by such physiological acclimation in relation to the high light environment (Guieu et al, 2013a).…”

Section: A Comparison Between Primary Production Poc and Lithogenicmentioning

confidence: 99%

See 3 more Smart Citations

Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

et al. 2014

Self Cite

View full text Add to dashboard Cite

Abstract. Lithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export to the deep ocean by acting as mineral ballasts. However, an accurate understanding and quantification of the POC-dust association that occurs within the upper ocean is required in order to refine the "ballast hypothesis". In the framework of the DUNE (a DUst experiment in a lowNutrient, low-chlorophyll Ecosystem) project, two artificial seedings were performed seven days apart within large mesocosms. A suite of optical and biogeochemical measurements were used to quantify surface POC export following simulated dust events within a low-nutrient, low-chlorophyll ecosystem. The two successive seedings led to a 2.3-6.7-fold higher POC flux than the POC flux observed in controlled mesocosms. A simple linear regression analysis revealed that the lithogenic fluxes explained more than 85 % of the variance in POC fluxes. On the scale of a dust-deposition event, we estimated that 42-50 % of POC fluxes were strictly associated with lithogenic particles (through aggregation and most probably sorption processes). Lithogenic ballasting also likely impacted the remaining POC fraction which resulted from the fertilization effect. The observations support the "ballast hypothesis" and provide a quantitative estimation of the surface POC export abiotically triggered by dust deposition. In this work, we demonstrate that the strength of such a "lithogenic carbon pump" depends on the biogeochemical conditions of the water column at the time of deposition. Based on these observations, we suggest that this lithogenic carbon pump could represent a major component of the biological pump in oceanic areas subjected to intense atmospheric forcing.

show abstract

Section: The Dynamics and Timing Of Particulate Exportmentioning

confidence: 86%

Section: A Comparison Between Primary Production Poc and Lithogenicmentioning

confidence: 97%

Section: Evolution Of the Physical And Biogeochemical Parametersmentioning

confidence: 99%

Section: A Comparison Between Primary Production Poc and Lithogenicmentioning

confidence: 99%

See 2 more Smart Citations

Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…When a second dust wet deposition was simulated, iron dissolution from the dust particles was then evidenced due to the excess Fe binding ligand concentrations produced by the enhanced biological activity (Wuttig et al 2013). When simulating dust wet deposition at least a doubling of Chla (mainly attributed to small phytoplankton (<3 μm); Giovagnetti et al 2013) was observed but the Chla concentrations remained very low (maximum values 0.22 μg L-1) maintaining the oligotrophic status of the tested waters . Laghdass et al (2011) investigated the effect of dust deposition on the diversity of the heterotrophic bacterial community.…”

Section: Experimental: In Situ Mesocosmsmentioning

confidence: 99%

Ocean–Atmosphere Interactions of Particles

Leeuw

Guieu

Arneth

et al. 2013

Springer Earth System Sciences

View full text Add to dashboard Cite

This chapter provides an overview of the current knowledge on aerosols in the marine atmosphere and the effects of aerosols on climate and on processes in the oceanic surface layer. Aerosol particles in the marine atmosphere originate predominantly from direct production at the sea surface due to the interaction between wind and waves (sea spray aerosol, or SSA) and indirect production by gas to particle conversion. These aerosols are supplemented by aerosols produced over the continents, as well as aerosols emitted by volcanoes and ship traffic, a large part of it being deposited to the ocean surface by dry and wet deposition. The SSA sources, chemical composition and ensuing physical and optical effects, are discussed. An overview is presented of continental sources and their ageing and mixing processes during transport. The current status of our knowledge on effects of marine aerosols on the Earth radiative balance, both direct by their interaction with solar radiation and indirect through their effects on cloud properties, is discussed. The deposition on the ocean surface of some key species, such as nutrients, their bioavailability and how they impact biogeochemical cycles are shown and discussed through different time and space scales approaches.

show abstract

The significance of the episodic nature of atmospheric deposition to Low Nutrient Low Chlorophyll regions

Guieu

Aumont

Paytan

et al. 2014

Global Biogeochemical Cycles

Self Cite

119

122

View full text Add to dashboard Cite

In the vast Low Nutrient Low-Chlorophyll (LNLC) Ocean, the vertical nutrient supply from the subsurface to the sunlit surface waters is low, and atmospheric contribution of nutrients may be one order of magnitude greater over short timescales. The short turnover time of atmospheric Fe and N supply (<1 month for nitrate) further supports deposition being an important source of nutrients in LNLC regions. Yet, the extent to which atmospheric inputs are impacting biological activity and modifying the carbon balance in oligotrophic environments has not been constrained. Here, we quantify and compare the biogeochemical impacts of atmospheric deposition in LNLC regions using both a compilation of experimental data and model outputs. A metadata-analysis of recently conducted field and laboratory bioassay experiments reveals complex responses, and the overall impact is not a simple "fertilization effect of increasing phytoplankton biomass" as observed in HNLC regions. Although phytoplankton growth may be enhanced, increases in bacterial activity and respiration result in weakening of biological carbon sequestration. The application of models using climatological or time-averaged non-synoptic deposition rates produced responses that were generally much lower than observed in the bioassay experiments. We demonstrate that experimental data and model outputs show better agreement on short timescale (days to weeks) when strong synoptic pulse of aerosols deposition, similar in magnitude to those observed in the field and introduced in bioassay experiments, is superimposed over the mean atmospheric deposition fields. These results suggest that atmospheric impacts in LNLC regions have been underestimated by models, at least at daily to weekly timescales, as they typically overlook large synoptic variations in atmospheric deposition and associated nutrient and particle inputs. Inclusion of the large synoptic variability of atmospheric input, and improved representation and parameterization of key processes that respond to atmospheric deposition, is required to better constrain impacts in ocean biogeochemical models. This is critical for understanding and prediction of current and future functioning of LNLC regions and their contribution to the global carbon cycle.

show abstract

Assessing the role of dust deposition on phytoplankton ecophysiology and succession in a low-nutrient low-chlorophyll ecosystem: a mesocosm experiment in the Mediterranean Sea

Cited by 42 publications

References 91 publications

Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

Ocean–Atmosphere Interactions of Particles

The significance of the episodic nature of atmospheric deposition to Low Nutrient Low Chlorophyll regions

Contact Info

Product

Resources

About