Seasonal variability of nutrient concentrations in the <scp>M</scp>editerranean <scp>S</scp>ea: Contribution of <scp>B</scp>io‐<scp>A</scp>rgo floats

Fommervault, Orens Pasqueron de; D’Ortenzio, Fabrizio; Mangin, Antoine; Serra, Romain; Migon, Christophe; Claustre, Hervé; Lavigne, Héloïse; d’Alcalà, Maurizio Ribera; Prieur, Louis; Taillandier, Vincent; Schmechtig, Catherine; Poteau, Antoine; Leymarie, Édouard; Dufour, Aurélie; Besson, Florent L.; Obolensky, Grigor

doi:10.1002/2015jc011103

Cited by 62 publications

(45 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the Mediterranean Sea, Lavigne et al (2013) showed that in the south Ionian Sea and in the Levantine Sea, the probability that the MLD reaches the nitracline depth is very low. These results were corroborated by a recent analysis based on Bio-Argo floats (Pasqueron de Fommervault et al, 2015). However, in regions where mesoscale circulation is cyclonic (e.g., south Adriatic gyre, Rhodes gyre), there is evidence of surface nutrient enrichment caused by vertical mixing (Gačić et al, 2002;Lascaratos et al, 1993;Salihoglu et al, 1990).…”

Section: Role Of the Nig Circulation Patterns Compared To The Interansupporting

confidence: 77%

See 1 more Smart Citation

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

et al. 2018

Self Cite

View full text Add to dashboard Cite

Abstract. In the north Ionian, water circulation is characterized by a decadal alternation of cyclonic and anticyclonic regime driven by the mechanism called BiOS (bimodal oscillating system). The circulation regimes affect both vertical dynamics and the nutrient distribution. The north Ionian is then a good study area to investigate how changes in circulation can affect phytoplankton dynamics in oligotrophic regions. From in situ observations, for each circulation regime the averaged distribution of isopycnals is provided, and a depth difference of about 80 m is estimated for the nitracline between the cyclonic and anticyclonic regime. Based on phytoplankton phenology metrics extracted from annual time series of satellite ocean color data for the period 1998-2012, the cyclonic and anticyclonic regimes are compared. Results show that the average chlorophyll in March, the date of bloom onset and the date of maximum chlorophyll were affected by circulation patterns in the north Ionian. In the center of the north Ionian gyre, the bloom started in December and chlorophyll was low in March when circulation was anticyclonic, whereas during the cyclonic circulation regime, a late chlorophyll peak, likely resulting from different phytoplankton dynamics, was commonly observed in March. An additional analysis shows that the winter buoyancy losses, which govern the mixed layer depth (MLD), also contribute to explaining the interannual variability in bloom onset and intensity. Two trophic regimes were then identified in the north Ionian gyre (NIG) and they could be explained with the relative position of the MLD and nitracline.The first one is characterized by an early winter bloom onset and the absence of a chlorophyll peak in March. It was observed when circulation was anticyclonic or when winter MLD was relatively shallow. Dominant regenerated production all year and an absence of significant nutrient supplies to surface waters are proposed to explain this trophic regime. Conversely, the second trophic regime is marked by a bloom onset in late winter (i.e., February) and a chlorophyll peak in March. The chlorophyll increase was interpreted as a direct response to the nutrient enrichment of surface waters. This winter-spring bloom was observed when circulation was cyclonic and when winter mixing was relatively strong.

show abstract

Section: Role Of the Nig Circulation Patterns Compared To The Interansupporting

confidence: 77%

“…From nitrate concentration profiles, the nitracline depth was estimated as the depth of the 1 µM isoline (Cermeño et al, 2008;Lavigne et al, 2013;Pasqueron de Fommervault et al, 2015) and compared to the depth of the 28.9 kg m −3 isopycnals (Fig. 3c).…”

Section: In Situ Datamentioning

confidence: 99%

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The method is based on the Owens and Millard (1985) algorithm that has been slightly adapted by Sea-Bird in the data processing software using a hysteresis correction (Sea-Bird Scientific, 2014). A new set of calibration coefficients for this sensor was determined after the cruise; it was used to post-process the whole data set.…”

Section: Data Processingmentioning

confidence: 99%

Hydrography and biogeochemistry dedicated to the Mediterranean BGC-Argo network during a cruise with RV <i>Tethys 2</i> in May 2015

Taillandier

Wagener

D’Ortenzio

et al. 2018

Earth Syst. Sci. Data

Self Cite

View full text Add to dashboard Cite

Abstract. We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea, on the French research vessel Tethys 2 in May 2015. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGCArgo floats. During the cruise, a comprehensive data set of parameters sensed by the autonomous network was collected. The measurements include ocean currents, seawater salinity and temperature, and concentrations of inorganic nutrients, dissolved oxygen and chlorophyll pigments. The analytical protocols and data processing methods are detailed, together with a first assessment of the calibration state for all the sensors deployed during the cruise.

show abstract

“…In turn this sinking of OM could explain its reduction in surface layers, together with decreases in bacteria and viruses, thought by the authors to have been filtered from the water by the sinking MOAs. Thus soot (and black carbon), as well as desert dusts (Pasqueron de Fommervault et al, 2015) may control foam and whitecap production globally by two mechanisms: foam destabilization; and reduction of surface OM concentrations by sticking to and ballasting MOAs, thus producing or increasing their sinking.…”

Section: Long-lived Foaming Eventsmentioning

confidence: 99%

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Jenkinson

Laurent

Ding

et al. 2018

Elementa: Science of the Anthropocene

View full text Add to dashboard Cite

Jenkinson, IR, et al. 2018 Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes. Elem Sci Anth, 6: 26. DOI: https://doi.org/10.1525/elementa.283 IntroductionFor over a century, CO 2 levels in the atmosphere have been increasing at an accelerating rate. This increase is fuelled by anthropogenic CO 2 release, currently at over 9 billion tonnes annually (Le Quéré, 2015). As a greenhouse gas, CO 2 is leading to higher mean temperature on Earth (Friedlingstein et al., 2014) and in the world ocean, as well as increasing sea levels by thermal expansion and melting of ice caps (IPCC, 2014).The Ocean absorbs about 25% of the anthropically produced excess CO 2 (Le Quéré et al., 2015). As a result, the average surface ocean pH has decreased 0.1 units since the Industrial Revolution, i.e., a 30% increase in acidity (IPCC, 2014), and is predicted to fall another 0.3 to 0.4 units by 2100 if CO 2 emissions continue in a business-asusual scenario (Orr et al., 2005).In order to predict, manage and adapt to future changes in CO 2 dynamics, models of air-sea flux of CO 2 are being refined. This flux of CO 2 passes through the barrier of the sea surface microlayer (SML), here considered to be the top 50(±10) µm (Zhang et al., 1998). As the SML itself varies strongly in time and space in complex, nonlinear ways, modelling the effects of the SML on CO 2 flux as a function of pertinent future scenarios is also important.The importance of the SML in biologically modulating fluxes, particularly of CO 2 , is increasingly appreciated, and has recently been reviewed by Wurl et al. (2016Wurl et al. ( , 2017 and by Engel et al. (2017b). Therefore, the aim of this paper is to review known and suspected mechanical aspects of how biologically produced organic matter (OM) modulates air-sea fluxes of CO 2 . We particularly address thalassorheological observations of biologically increased 3D viscosity and elasticity, 2D compression-dilation rheology, 2D shear rheology and foam dynamics. Gas exchange reduction (GER) at the air-sea interface is positively related to the concentration of organic matter (OM) in the top centimetre of the ocean, as well as to phytoplankton abundance and primary production. The mechanisms relating OM to GER remain unclear, but may involve mechanical (rheological) damping of turbulence in the water immediately below the surface microlayer, damping of ripples and blocking of molecular diffusion by layers of OM, as well as electrical effects. To help guide future research in GER, particularly of CO 2 , we review published rheological properties of ocean water and cultures of phytoplankton and bacteria in both 3D and 2D deformation geometries, in water from both the surface layer and underlying water. Production of foam modulates air-sea exchange of many properties and substances, perhaps including climate-changing gases such as CO 2 . We thus also review biological modulation of production and decay of whitecaps and other sea foam. In the ocea...

show abstract

Seasonal variability of nutrient concentrations in the Mediterranean Sea: Contribution of Bio‐Argo floats

Cited by 62 publications

References 97 publications

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

Hydrography and biogeochemistry dedicated to the Mediterranean BGC-Argo network during a cruise with RV <i>Tethys 2</i> in May 2015

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Contact Info

Product

Resources

About

Seasonal variability of nutrient concentrations in the Mediterranean Sea: Contribution of Bio‐Argo floats

Cited by 62 publications

References 97 publications

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

Impact of decadal reversals of the north Ionian circulation on phytoplankton phenology

Hydrography and biogeochemistry dedicated to the Mediterranean BGC-Argo network during a cruise with RV &lt;i&gt;Tethys 2&lt;/i&gt; in May 2015

Biological modification of mechanical properties of the sea surface microlayer, influencing waves, ripples, foam and air-sea fluxes

Contact Info

Product

Resources

About

Hydrography and biogeochemistry dedicated to the Mediterranean BGC-Argo network during a cruise with RV <i>Tethys 2</i> in May 2015