Browsing by Author "Maiorano, Patrizia"
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- Coccolithophores as proxy of seawater changes at orbital-to-millennial scale during middle Pleistocene Marine Isotope Stages 14-9 in North Atlantic core MD01-2446Publication . Marino, Maria; Maiorano, Patrizia; Tarantino, Francesca; Voelker, Antje; Capotondi, Lucilla; Girone, Angela; Lirer, Fabrizio; Flores, José-Abel; Naafs, B. David A.midlatitude North Atlantic, to reconstruct climatically induced sea surface water conditions throughout Marine Isotope Stages (MIS) 14–9. The data are compared to new and available paleoenvironmental proxies from the same site as well as other nearby North Atlantic records that support the coccolithophore signature at glacial‐interglacial to millennial climate scale. Total coccolithophore absolute abundance increases during interglacials but abruptly drops during the colder glacial phases and deglaciations. Coccolithophore warm water taxa (wwt) indicate that MIS11c and MIS9e experienced warmer and more stable conditions throughout the whole photic zone compared to MIS13. MIS11 was a long‐lasting warmer and stable interglacial characterized by a climate optimum during MIS11c when a more prominent influence of the subtropical front at the site is inferred. The wwt pattern also suggests distinct interstadial and stadial events lasting about 4–10 kyr. The glacial increases of Gephyrocapsa margereli‐G. muellerae 3–4 µm along with higher values of Corg, additionally supported by the total alkenone abundance at Site U1313, indicate more productive surface waters, likely reflecting the migration of the polar front into the midlatitude North Atlantic. Distinctive peaks of G. margereli‐muellerae (>4 µm), C. pelagicus pelagicus , Neogloboquadrina pachyderma left coiling, and reworked nannofossils, combined with minima in total nannofossil accumulation rate, are tracers of Heinrich‐type events during MIS12 and MIS10. Additional Heinrich‐type events are suggested during MIS12 and MIS14 based on biotic proxies, and we discuss possible iceberg sources at these times. Our results improve the understanding of mid‐Brunhes paleoclimate and the impact on phytoplankton diversity in the midlatitude North Atlantic region.
- Early Pleistocene calcareous nannofossil assemblages from the Gulf of Cadiz reveal glacial-interglacial and millennial-scale variabilityPublication . Trotta, Samanta; Marino, Maria; H L Voelker, Antje; Rodrigues, Teresa; Maiorano, Patrizia; Flores, José-Abel; Girone, Angela; Addante, Marina; Balestra, BarbaraCoccolithophore high resolution (300 years) quantitative analyses have been carried out on Early Pleistocene sediment samples from Integrated Ocean Drilling Program Site U1387 retrieved in the Gulf of Cadiz. The studied interval is well constrained by the delta 18O chronological frame and covers marine isotope stage (MIS) 48 to MIS 45, from 1465.9 ka to 1389.9 ka. The aim is to investigate paleoenvironmental changes during a poorly known interval of the "41 ky world" and understand how climate dynamics controlled coccolithophore abundance and variation at orbital up to millennial scale. Assemblage composition variation and Principal Component Analysis (PCA) indicate that temperature and nutrient availability are the main factors influencing coccolithophores. Precession forcing combined with hydrological and atmospheric dynamics affect changes in coccolithophore assemblage composition and abundance highlighting glacial-interglacial cycles and a millennial scale variability, which is more evident during glacials than during interglacials. Interglacial MIS 47 onset is more abrupt than MIS 45 inception in relation to a more prominent insolation maximum, which favors the sharp increase and highest abundance of warm water taxa in the early MIS 47. Short-term abundance peaks of C. pelagicus spp. pelagicus during glacials document polar-subpolar melting water influx into the Gulf of Cadiz and southward migration of the subpolar front during episodes of high volume ice-sheet in the north hemisphere and reduced Atlantic Meridional Overturning circulation. In late MIS 48 the lowest coccolithophore productivity, induced by colder and stratified surface waters, a terminal stadial has been inferred. Enhanced short-term glacial productivity is favored by higher mixing and nutrient content in surface water due to the strengthened westerly winds during symbolscript phases. This promotes arid condition and upwelling along the studied site. The interglacial short-term coccolithophore productivity increases are associated with insolation maxima and enhanced nutrients of land origin during more humid periods led by -NAO-like phases, which induce the southward position of the westerlies and higher precipitation in the Mediterranean region and North Africa, in agreement with the contemporary sapropel occurrences in Mediterranean Sea. Our data-set suggests a connection between climate dynamics in the Gulf of Cadiz and east of Gibraltar Strait during the Early Pleistocene as well as a relationship with the north hemisphere ice-sheet dynamics.
- Holocene climate variability of the Western Mediterranean: surface water dynamics inferred from calcareous plankton assemblagesPublication . Bazzicalupo, Pietro; Maiorano, Patrizia; Girone, Angela; Marino, Maria; Combourieu-Nebout, Nathalie; Pelosi, Nicola; Salgueiro, Emilia; Incarbona, AlessandroA high-resolution study (centennial scale) has been performed on the calcareous plankton assemblage of the Holocene portion of the Ocean Drilling Program Site 976 (Alboran Sea) with the aim to identify the main changes in the surface water dynamic. The dataset also provided a seasonal foraminiferal sea surface water temperatures (SSTs), estimated using the modern analog technique SIMMAX 28, and it was compared with available geochemical and pollen data at the site. Three main climate shifts were identified as (1) the increase in abundance of Syracosphaera spp. and Turborotalita quinqueloba marks the early Holocene humid phase, during maximum summer insolation and enhanced river runoff. It is concomitant with the expansion of Quercus, supporting high humidity on land. It ends at 8.2 ka, registering a sudden temperature and humidity reduction; (2) the rise in the abundances of Florisphaera profunda and Globorotalia inflata, at ca. 8 ka, indicates the development of the modern geostrophic front, gyre circulation, and of a deep nutricline following the sea-level rise; and (3) the increase of small Gephyrocapsa and Globigerina bulloides at 5.3 ka suggests enhanced nutrient availability in surface waters, related to more persistent wind-induced upwelling conditions. Relatively higher winter SST in the last 3.5 ka favored the increase of Trilobatus sacculifer, likely connected to more stable surface water conditions. Over the main trends, a short-term cyclicity is registered in coccolithophore productivity during the last 8 ka. Short periods of increased productivity are in phase with Atlantic waters inflow, and more arid intervals on land. This cyclicity has been related with periods of positive North Atlantic Oscillation (NAO) circulations. Spectral analysis on coccolithophore productivity confirms the occurrence of millennial-scale cyclicity, suggesting an external (i.e. solar) and an internal (i.e. atmospheric/oceanic) forcing.
- Multiproxy record of suborbital-scale climate changes in the Algero-Balearic Basin during late MIS 20-Termination IXPublication . Quivelli, Ornella; Marino, Maria; Rodrigues, Teresa; Girone, Angela; Maiorano, Patrizia; Bertini, Adele; Niccolini, Gabriele; Trotta, Samanta; Bassinot, FranckHigh-resolution quantitative analyses have been carried out in samples from the Ocean Drilling Program (ODP) Site 975 in the Algero-Balearic basin through late Marine Isotope Stage (MIS 20)-Termination IX (800-784 ka). The multi-proxy study combines data of planktonic delta O-18, delta C-13, calcareous plankton (coccolithophores, foraminifera), palynomorphs, alkenone-based sea surface temperature (SST), % alkenone tetraunsatured (% C-37:4), and terrigenous biomarkers (C-23-C-31 n-alkanes, C-22-C-30 n-alkanols) with the aim to reconstruct climate-induced paleoenvironmental changes at orbital-submillennial scale, in a crucial time interval of the Early-Midde Pleistocene transition. The surface water delta O-18(sw) has been reconstructed from delta O-18(G.bulloides) and alkenone-based SST as a proxy for salinity changes. The late MIS 20 has been subdivided in several phases based on evidence of (i) meltwater events of polar origin or from surrounding mountain glaciers, (ii) changes in the production rate of Western Mediterranean Deep Water (WMDW) and in deep water ventilation, (iii) variation in terrestrial input and river discharge, and iv) variations in the strength of the north westerlies, and polar front shift. Following a glacial stadial (lasting ca 3 kyr) marked by the strongest WMDW production, coeval with a boreal summer insolation minimum and a marked low sea level, the latest MIS 20 is characterized by a terminal stadial event (lasting ca 3.5 kyr), which is traced by the occurrence of cold-low salinity water, pointing to meltwater advection at the site location. Short-term warm and cool events occurred through Termination IX during sea level rise and insolation increase, preceding the onset of full MIS 19c, characterized by an organic rich layer (ORL) associated with insolation cycle 74. The succession of these climate and oceanographic events has been compared to evidences from other Mediterranean sites, highlighting similar basin-wide patterns, which recall the climate evolution of Termination I. The comparison of our results with the climate proxies from the Integrated Ocean Drilling Program (IODP) Site U1385 located west of Iberian margin made it possible to point at the connection between Mediterranean oceanographic and atmospheric dynamics and the northern hemisphere ice-sheet instability, providing insight on the relationship with the Atlantic meridional overturning circulation and thermal front migration. (C) 2021 Elsevier Ltd. All rights reserved.
- A new perspective of the Alboran Upwelling System reconstruction during the Marine Isotope Stage 11: a high-resolution coccolithophore recordPublication . González-Lanchas, Alba; Flores, José-Abel; Sierro, Francisco J.; Bárcena, María Ángeles; Rigual-Hernández, Andrés S.; Oliveira, Dulce; Azibeiro, Lucía A.; Marino, Maria; Maiorano, Patrizia; Cortina, Aleix; Cacho, Isabel; Grimalt, Joan O.A high-resolution study of the MIS 12/MIS 11 transition and the MIS 11 (430-376 kyr) coccolithophore assemblages at Ocean Drilling Program Site 977 was conducted to reconstruct the palaeoceanographic and climatic changes in the Alboran Sea from the variability in surface water conditions. The nannofossil record was integrated with the planktonic oxygen and carbon stable isotopes, as well as the U-37(k') Sea Surface Temperature (SST) at the studied site during the investigated interval. The coccolithophore primary productivity, reconstructed from the PPP (primary productivity proxy = absolute values of Gephyrocapsa caribbeanica + small Gephyrocapsa group) revealed pronounced fluctuations, that were strongly associated with variations in the intensity of the regional Alboran Upwelling System. The comparison of the nannoplankton record with opal phytolith content for the studied site and the already available pollen record at the nearby Integrated Ocean Drilling Program Site U1385, suggests an association of the upwelling dynamics with the variability of the North Atlantic Oscillation-like (NAO-like) phase. High PPP during positive (+) NAO-like phases is the result of intensified upwelling, owing to the complete development of the surface hydrological structures at the Alboran Sea. This scenario was identified during the MIS 12/MIS 11 transition (428-422 kyr), the late MIS 11c (405-397 kyr), and MIS11 b to MIS 11a (397-376 kyr). Two short-term minima in the PPP and SST were observed during MIS 11 b and were coeval with the North Atlantic Heinrich-type (Ht) events Ht3 (similar to 390 kyr) and Ht2 (similar to 384 kyr). Increased abundance of the subpolar Coccolithus pelagicus subsp. pelagicus and Gephyrocapsa muellerae was consistent with the inflow of cold surface waters into the Mediterranean Sea during the Ht events. Lowered PPP during negative (-) NAO-like phases is the result of moderate upwelling by the incomplete development of surface hydrological structures at the Alboran Sea. This scenario is expressed during the early MIS 11c (422-405 kyr). Overall, the results of our study provide evidence of the important role of atmospheric circulation patterns in the North Atlantic region for controlling phytoplankton primary production and oceanographic circulation dynamics in the Western Mediterranean during MIS 11.
- Paleoproductivity proxies and alkenone precursors in the Western Mediterranean during the Early-Middle Pleistocene transitionPublication . Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, FranckMultidisciplinary analyses (taxonomic analysis of coccolithophore assemblages, stable oxygen isotopes, marine and terrestrial biomarkers) have been carried out on sediments from Ocean Drilling Program Site 975 in the Algero-Balearic basin, through late marine isotope stage (MIS) 20-19 (800-756 ka). The aim is to compare coccolithophore paleoproductivity proxies, such as C-37 alkenone concentration and nannofossil accumulation rate (NAR), and understand their relationship with paleoceanographic condition and paleoenvironmental changes, alkenone-producing precursors and unsaturated C-37 alkenone compounds. The patterns of C-37 alkenones and NAR provide reliable information on past paleoproductivity changes since coccolith dissolution and organic matter preservation were excluded as relevant processes at the site. This is testified by the high values of Nannofossil Dissolution Index and relation between C-37 alkenone concentration and Alcohol Preservation Index, the latter used as a proxy of sea bottom ventilation in the basin. A weak mismatching between NAR and C-37 alkenone concentration records has been observed and related to paleoenvironmental factors and ecological preferences of alkenone-producing species. Temperature variations mostly controlled the alternating interspecific abundance variations of these taxa through glacial-interglacial and stadial-interstadial climate phases. The percentage abundances of alkenone-producing species, Gephyrocapsa caribbeanica and Gephyrocapsa with open central area (mainly G. margerelii-G. muellerae) strongly co-varied with the percentages of C-37:2 and C-37:3, respectively during warm and cool-cold periods, suggesting their prominent role in producing these unsaturated C-37 alkenone compounds. Moreover, Gephyrocapsa spp. with open central area > 3 mu m were likely the main C-37:4 producers during the colder late MIS 20 stadial and stadial phases. Other factors in addition to temperature influenced the paleoproductivity proxy patterns. The oceanographic condition established during MIS 20-MIS 19 deglaciation and the more nutrient-rich surface waters during the orbitally-controlled organic-rich layer deposition in the early MIS 19 enhanced primary productivity leading to higher production and preservation of total C-37 alkenones.
- Surface and deep water variability in the Western Mediterranean (ODP Site 975) during insolation cycle 74: high-resolution calcareous plankton and molecular biomarker signalsPublication . Quivelli, Ornella; Marino, Maria; Rodrigues, Teresa; Girone, Angela; Maiorano, Patrizia; Abrantes, Fatima; Salgueiro, Emilia; Bassinot, FrankWe reconstructed changes in productivity and surface/subsurface and deep-water dynamics in the Western Mediterranean through a multi-proxy study of Ocean Drilling Program Site 975 between late Marine Isotope Stage (MIS) 20 and early interglacial MIS 19. Our high-resolution study (down to similar to 200-year resolution) combines calcareous plankton assemblages (coccolithophores and foraminifera), biomarkers (C-37-alkenones, n-alkanes, n-alcohols) and elemental proxies (total organic carbon, total nitrogen, calcium carbonate). Surface water conditions are derived (i) from high-resolution delta O-18 and delta C-13 records obtained from the planktonic foraminifer Globigerina bulloides, and (ii) from summer and winter, foraminifera-based sea surface temperature reconstructions (SSTJAS-foram, SSTJFM-foram) achieved through transfer function. The integration of the whole dataset makes it possible to identify in the Balearic Sea, and to accurately characterize for the first time, an Organic Rich Layer (ORL) during latest MIS 20-early MIS 19, close to i-cycle 74. Its presence is marked firstly by higher values of total nitrogen (TN) and an increase of total C-37-alkenone and total organic carbon (TOC) preserved in the sediments. The multi-proxy approach reveals that the deglacial phase played a prominent role for ORL formation that was characterized by centennial scale phases. The alcohol preservation index (API) suggests that the shoaling of the circulation, which boosted marine productivity, started in the deglaciation and, in combination with freshening by Atlantic water inflow/riverine input and surface water buoyancy during sea level rising, culminated during the ORL event. At this time calcareous plankton proliferated on subsurface-surface waters, benefiting from ameliorating conditions, which promoted maximum marine productivity and higher organic matter preservation on the seafloor.