In press / In Revision / Submitted

Kheireddine, M., N., Mayot, M. Ouhssain and B. H. Jones. Regionalization of the Red Sea based on phytoplankton phenology: a satellite analysis | Submitted to Journal of Geophysical Research: Oceans


Mayot, N., P. A. Matrai, A. Arjona, S. Bélanger, C. Marchese, T. Jaegler, M. Ardyna and M. Steele (2020). Springtime export of Arctic sea ice influences phytoplankton production in the Greenland Sea | Journal of Geophysical Research: Oceans | 125(3), e2019JC015799 | PDF


Climate model projections suggest a substantial decrease of sea ice export into the outflow areas of the Arctic Ocean over the 21st century. Fram Strait, located in the Greenland Sea sector, is the principal gateway for ice export from the Arctic Ocean. The consequences of lower sea ice flux through Fram Strait on ocean dynamics and primary production in the Greenland Sea remain unknown. By using the most recent 16 years (2003–2018) of satellite imagery available and hydrographic in situ observations, the role of exported Arctic sea ice on water column stratification and phytoplankton production in the Greenland Sea is evaluated. Years with high Arctic sea ice flux through Fram Strait resulted in high sea ice concentration in the Greenland Sea, stronger water column stratification, and an earlier spring phytoplankton bloom associated with high primary production levels. Similarly, years with low Fram Strait ice flux were associated with a weak water column stratification and a delayed phytoplankton spring bloom. This work emphasizes that sea ice and phytoplankton production in subarctic “outflow seas” can be strongly influenced by changes occurring in the Arctic Ocean.

Ardyna, M., C.J. Mundy, N. Mayot, L.C. Matthes, L. Oziel, C. Horvat, E. Leu, P. Assmy, V. Hill, P. A. Matrai and M. Gale (2020). Under-ice phytoplankton blooms: shedding light on the ‘invisible’ part of Arctic primary production | Frontiers in Marine Science | 7, 985 | PDF


Mayot, N., P. A. Matrai, I. H. Ellingsen, M. Steele, K. Johnson, S. C. Riser and D. Swift (2018). Assessing Phytoplankton Activities in the Seasonal Ice Zone of the Greenland Sea Over an Annual Cycle | Journal of Geophysical Research: Oceans | 123(11), 8004-8025 | PDF


In seasonal ice zones (SIZs), such as the one of the Greenland Sea, the sea ice growth in winter and subsequent melting in summer influence the phytoplankton activity. However, studies assessing phytoplankton activities over complete annual cycles and at a fine temporal resolution are lacking in this environment. Biogeochemical-Argo floats, which are able to sample under the ice, were used to collect physical and biogeochemical data along vertical profiles and at 5-day resolution during two complete annual cycles in the Greenland Sea SIZ. Three phytoplankton activity phases were distinct within an annual cycle: one under ice, a second at the ice edge, and a third one around an open-water subsurface chlorophyll maximum. As expected, the light and nitrate availabilities controlled the phytoplankton activity and the establishment of these phases. On average, most of the annual net community production occurred equally under ice and at the ice edge. The open-water subsurface chlorophyll maximum phase contribution, on the other hand, was much smaller. Phytoplankton biomass accumulation and production thus occur over a longer period than might be assumed if under ice blooms were neglected. This also means that satellite-based estimates of phytoplankton biomass and production in this SIZ are likely underestimated. Simulations with the Arctic-based physical-biologically coupled SINMOD model suggest that most of the annual net community production in this SIZ results from local processes rather than due to advection of nitrate from the East Greenland and Jan Mayen Currents.

Ayata, S-D., J-O. Irisson, A. Aubert, L. Berline, J-C. Dutay, N. Mayot, A-E. Nieblas, F. D’Ortenzio, J. Palmieri, G. Reygondeau, V. Rossi, and C. Guieu (2018). Regionalisation of the Mediterranean basin, a MERMEX synthesis | Progress in Oceanography | 163, 7-20 | PDF

Taillandier, V., T. Wagener, F. D’Ortenzio, N. Mayot, H. Legoff, J. Ras, L. Coppola, O. Pasqueron de Fommervault1, C. Schmechtig, E. Diamond, H. Bittig, D. Lefevre, E. Leymarie, A. Poteau and L. Prieur (2018). Hydrography in the Mediterranean Sea during a cruise with RV Tethys 2 in May 2015 | Earth System Science Data | 10(1), 627-641 | PDF

Testor, P., A. Bosse, L. Houpert, F. Margirier, L. Mortier, H. Le Goff, D. Dausse, M. Labaste, J. Karstensen, D. Hayes, A. Olita, E. Heslop, F. D’Ortenzio, N. Mayot, H. Lavigne, O. Pasqueron de Fommervault, L. Coppola, L. Prieur, V. Taillandier, X. Durrieu de Madron, F. Bourrin, G. Many, P. Damien, C. Estournel, P. Marsaleix, I. Taupier-Letage, P. Raimbault, R. Waldman, M-N. Bouin, H. Giordani, G. Caniaux, S. Somot, V. Ducrocq and P. Conan (2018). Dense water formations in the North Western Mediterranean: from the physical forcings to the biogeochemical consequences | Journal of Geophysical Research: Oceans | 123(3), 1745-1776 | PDF


Mayot, N., F. D’Ortenzio, J. Uitz, B. Gentili, D. Antoine and H. Claustre (2017). Influence of the phytoplankton community structure on the spring and annual primary production in the North-Western Mediterranean Sea | Journal of Geophysical Research: Oceans | 122(12), 9918-9936 | PDF


Satellite ocean color observations revealed that unusually deep convection events in 1999, 2005, 2006, 2010 and 2013 led to an increased phytoplankton biomass during the spring bloom over a large area of the North-Western Mediterranean Sea (NWM). Here we investigate the effects of these events on the seasonal phytoplankton community structure, we quantify their influence on primary production, and we discuss the potential biogeochemical impact. For this purpose, we compiled in situ phytoplankton pigment data from five ship surveys performed in the NWM and from monthly cruises at a fixed station in the Ligurian Sea. We derived primary production rates from a light-photosynthesis model applied to these in situ data. Our results confirm that the maximum phytoplankton biomass during the spring bloom is larger in years associated with intense deep convection events (+ 51%). During these enhanced spring blooms, the contribution of diatoms to total phytoplankton biomass increased (+ 33 %), as well as the primary production rate (+ 115 %). The occurrence of a highly productive bloom is also related to an increase in the phytoplankton bloom area (+ 155 %), and in the relative contribution of diatoms to primary production (+ 63 %). Therefore, assuming that deep convection in the NWM could be significantly weakened by future climate changes, substantial decreases in the spring production of organic carbon and of its export to deep waters can be expected.

Mayot, N., F. D’Ortenzio, V. Taillandier, L. Prieur, O. Pasqueron de Fommervault, H. Claustre, A. Bosse, P. Testor and P. Conan (2017). Physical and biogeochemical controls of the phytoplankton blooms in North Western Mediterranean Sea: a multiplatform approach over a complete annual cycle (2012-2013 DEWEX experiment) | Journal of Geophysical Research: Oceans | 122(12), 9999-10019 | PDF


The North Western Mediterranean Sea exhibits recurrent and significant autumnal and spring phytoplankton blooms. The existence of these two blooms coincide with typical temperate dynamics. To determine the potential control of physical and biogeochemical factors on these phytoplankton blooms, data from a multiplatform approach (combining ships, Argo and BGC-Argo floats, and bio-optical gliders) were analyzed in association with satellite observations in 2012-2013. The satellite framework allowed a simultaneous analysis over the whole annual cycle of in situ observations of mixed layer depth, photosynthetical available radiation, particle backscattering, nutrients (nitrate and silicate) and chlorophyll-a concentrations. During the year 2012-2013, satellite ocean color observations, confirmed by in situ data, have revealed the existence of two areas (or bioregions) with comparable autumnal blooms but contrasting spring blooms. In both bioregions, the ratio of the euphotic zone (defined as the isolume 0.415 mol photons m-2 d-1, Z0.415) and the MLD identified the initiation of the autumnal bloom, as well as the maximal annual increase in [Chl-a] in spring. In fact, the autumnal phytoplankton bloom might be initiated by mixing of the summer shallowing deep chlorophyll maximum, while the spring restratification (when Z0.415/MLD ratio became > 1) might induce surface phytoplankton production that largely overcomes the losses. Finally, winter deep convection events that took place in one of the bioregions induced higher net accumulation rate of phytoplankton in spring associated with a diatom-dominated phytoplankton community principally. We suggest that very deep winter MLD lead to an increase in surface silicates availability, which favored the development of diatoms.

Bosse, A., P. Testor, N. Mayot, L. Prieur, F. D’Ortenzio, L. Mortier, H. Le Goff, C. Gourcuff, L. Coppola, H. Lavigne and P. Raimbault, A submesoscale coherent vortex in the Ligurian Sea: from dynamical barriers to biological implications | Journal of Geophysical Research: Oceans | 122(8), 6196–6217 | PDF

Séverin, T., F. Kessouri, M. Rembauville, E. Sanchéz-Pérez, L. Oriol, J. Caparros, M. Pujo-Pay, J-F. Ghiglione, F. D’Ortenzio, V. Taillendier, C. Ulses, C. Estournel, N. Mayot and P. Conan (2017). Open-ocean convection process: a driver of the winter nutrient supply and the spring phytoplankton distribution in the Northwestern Mediterranean Sea | Journal of Geophysical Research: Oceans | 122(6), 4587–4601 | PDF


Biard, T., L. Stemmann, M. Picheral, N Mayot, P. Vandromme, H. Hauss, G. Gorsky, L. Guidi, R. Kiko and F. Not (2016). In situ imaging reveals the biomass of giant protists in the global ocean | Nature | 532, 504-507 | PDF on ResearchGate

Mayot, N., F. D’Ortenzio, M. Ribera d’Alcalà, H. Lavigne, and H. Claustre (2016). Interannual variability of the Mediterranean trophic regimes from ocean color satellites | Biogeosciences | 13, 1901–1917 | PDF


D’Ortenzio and Ribera d’Alcalà (2009, DR09 hereafter) divided the Mediterranean Sea into “bioregions” based on the climatological seasonality (phenology) of phytoplankton. Here we investigate the interannual variability of this bioregionalization. Using 16 years of available ocean color observations (i.e. SeaWiFS and MODIS), we analyzed the spatial distribution of the DR09 trophic regimes on an annual basis. Additionally, we identified new trophic regimes, exhibiting seasonal cycles of phytoplankton biomass different from the DR09 climatological description and named “Anomalous”. Overall, the classification of the Mediterranean phytoplankton phenology proposed by DR09 (i.e. “No Bloom”, “Intermittently”, “Bloom” and “Coastal”), is confirmed to be representative of most of the Mediterranean phytoplankton phenologies. The mean spatial distribution of these trophic regimes (i.e. bioregions) over the 16 years studied is also similar to the one proposed by DR09, although some annual variations were observed at regional scale. Discrepancies with the DR09 study were related to interannual variability in the sub-basin forcing: winter deep convection events, frontal instabilities, inflow of Atlantic or Black Sea Waters and river run-off. The large assortment of phytoplankton phenologies identified in the Mediterranean Sea is thus verified at the interannual scale, further supporting the “sentinel” role of this basin for detecting the impact of climate changes on the pelagic environment.

Book Chapter

Mayot, N., P. Nival and M. Lévy (2020). Primary Production in the Ligurian Sea | In C. Migon, P. Nival, A. Sciandra (Eds.), The Mediterranean Sea in the Era of Global Change 1: 30 Years of Multidisciplinary Study of the Ligurian Sea, Environmental Sciences Series (pp. 139-164) | London, UK: ISTE Ltd and John Wiley & Sons, Inc. PDF


The oceanographic and ecological characteristics of phytoplankton dynamics in the Ligurian Sea had been described in the 1960s from transects across the area and related to some physical–biogeochemical processes. This chapter provides an overview of the micro-, nano- and picophytoplankton species. Recurrent estimations of annual primary production cycles in the euphotic layer of the central Ligurian Sea were obtained at the DYFAMED sampling station. Associated with general annual cycle of phytoplankton dynamics, small spatiotemporal processes occur and may play a lead role at local scales. The biogeochemistry of the Ligurian Sea shares important characteristics with other temperate regions of the ocean, such as the North Atlantic. Modeling studies of this complex system has paved the way for the understanding of the coupling between the physics of the ocean and the response of the biogeochemistry in environments that are prone to strong seasonal variations of the surface mixed layer and to strong mesoscale dynamics.