Palynology of the northwestern Mediterranean shelf (Gulf of Lions): First vegetational record for the last climatic cycle

Beaudouin, Célia; Suc, Jean‐Pierre; Acherki, Nabila; Courtois, L.; Rabineau, Marina; Aloïsi, Jean-Claude; Sierro, Francisco J.; Oberlin, Christine

doi:10.1016/j.marpetgeo.2005.03.005

Cited by 20 publications

(17 citation statements)

References 41 publications

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“…5d). This assumption is sustained by the pollen analysis made on the twin core that showed an important amount of reworked pollen at this depth (5 m, 18.7 ka with our age model) (Beaudouin et al, 2005;Sierro et al, 2009). The hypothesis of an increased terrestrial input is reinforced by two geochemical markers (Ti/Al, Fig.…”

Section: Gulf Of Lionsupporting

confidence: 61%

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

et al. 2012

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Abstract. An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial Published by Copernicus Publications on behalf of the European Geosciences Union. 3492M.-C. Ciobanu et al.: Sedimentological imprint on subseafloor microbial communities inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary.

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Section: Gulf Of Lionsupporting

confidence: 61%

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

et al. 2012

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“…The 27.6-28.4 m interval is problematic since the 14 C age at 28.5 m (Table 1) places this interval within MIS 3. This appears inconsistent with the pollen flora, which is significantly different from that of the MIS 3 found in the Gulf of Lion (Beaudouin et al 2005), but that clearly indicates interglacial conditions. This discrepancy can be solved in two ways: (1) either we reject the 14 C age and attribute this interval as well as the underlying one (29.40-29.60 m core depth) to interglacial conditions, i.e., to MIS 5; or (2) we consider that the 14 C age is valid and suggest the presence of important mesophilous forest refuges in the Roussillon plain during MIS FIG.…”

Section: Cyclothemic Nature Of the Infilling Inferred From Facies Andcontrasting

confidence: 80%

“…One group is composed mainly of mesophilous trees (Quercus, Carpinus, Corylus, etc. ), which develop during warm and relatively humid phases, and the other group is composed of grasses and shrubs (including steppe elements such as Artemisia), which prevail during cold and dry phases (Suc 1984;Combourieu-Nebout and Vergnaud-Grazzini 1991;Beaudouin et al 2005;Suc and Popescu 2005).…”

Section: Pollen Recordmentioning

confidence: 99%

Quaternary "Compound" Incised Valley In A Microtidal Environment, Roussillon Continental Shelf, Western Gulf of Lions, France

Tesson¹,

Labaune²,

Gensous³

et al. 2011

Journal of Sedimentary Research

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A buried system was observed using seismic data along the northern side of the Roussillon coastal plain and inner shelf (Western Gulf of Lion, Mediterranean Sea) far from the nearest Agly and Têt rivers. It was interpreted as an example of a ''compound'' type, which is subject to controversy.A core 60 meters long was obtained on the sandy beach barrier between sea and lagoon approximately on the axis of the basal surface of erosion mapped from seismic data and long core logs obtained previously on the coastal plain.In the lower part of the core (264 m to 226 m b.p.s.l.) the main estuarine muddy-silt facies and thin levels of fluvial gravels intercalated in the mud suggest that successive cycles of base-level and sea-level falls and rises were recorded. This interpretation is confirmed by pollen diagrams showing several successive warming periods during climatic changes (differentiated as ''interglacial'' phases) recorded by the estuarine muds. Owing to these correlated data we can attest that this incised-valley system is of a ''compound'' type.Every vertical succession of fluvial gravels and estuarine muddy silts represents a fundamental depositional sequence typical of the ''simple'' model of wave-dominated incised-valley filling, truncated at the top by a subsequent base-level fall. Several depositional sequence remnants are stacked upon each other.The chronostratigraphic benchmark is based on microforaminiferal biomarkers which indicate that the time period covered by the successive phases of base-level and sea-level cycles extends from MIS 16 (about 600,000 years B.P.) to MIS1 (present day). The exact correlation of base level and sea level cycles with identified climate cycles remains partly approximate, but the cycles which contain well-known plant associations are quite reliable.The internal geometry of the incised-valley system, based upon high-resolution seismic data, shows that the lateral migration of the successive phases of incision and filling explains both the preservation of several cycles and the incomplete preservation of the typical facies due to the reworking of the upper part of all individual depositional sequences.Eustasy is the dominant controlling factor, and differential subsidence, an important factor on the mid and outer shelf, has a reduced impact at this location. The preservation of the ''compound'' system depends upon the variable maximum depth of erosion reached at each maximum sea-level lowstand. We propose that different interglacial conditions took place in the drainage basins, rather than differences in the lowstand-sea-level values. The transverse shape of the incisions, with lateral terraces and deeper channels, combined with a continuous lateral shift of the successive incisions, also contributed to preservation. The lateral shifting is partly due to a normal fault and substratum tilting, and partly to the oceanic regime.

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“…The frequent records of the species in eastern and north‐eastern Iberia and south‐eastern France were probably linked to the expansion in these regions of deciduous Quercus , evidenced by several pollen sequences (Pla de l'Estany in Burjachs , Capestang in Jalut , and Gulf of Lion in Beaudouin et al. among others). Thus, the Neolithic seems to be the acme of the evolutionary history of Microtus cabrerae , though earlier periods with limited palaeontological records, such as the Eemian in the early Late Pleistocene, may have been favourable for the species.…”

Section: Changes In the Geographic Distribution Of Microtus Cabrerae mentioning

confidence: 95%

Documenting the biogeographic history ofMicrotus cabreraethrough its fossil record

Laplana

Sevilla²

2013

Mammal Review

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Microtus cabrerae is an Iberian endemic vole species with specific adaptations to the subhumid Mediterranean climate. Its living populations are under a regressive trend. The earliest known records of Microtus cabrerae date from the late Middle Pleistocene, and it originated from Microtus brecciensis. We describe changes in the geographic distribution of Microtus cabrerae throughout its history based on its palaeontological record, and link them to environmental changes that have taken place since the appearance of Microtus cabrerae. A series of successive chronological intervals comprising the recorded existence of the species was established, so that the majority of the published fossil records of Microtus cabrerae could be used for analysis. For each interval, a map with the inferred distribution of the species was created. The maps were used to establish variations in the species' distribution through time. A first regression in the extent of the distribution of Microtus cabrerae took place in Marine Isotope Stage 2, when the species abandoned south‐eastern France and central Spain, where it had been present since the beginning of the Late Pleistocene. This range contraction was probably due to the global decline in temperatures and rainfall that took place in this period. After a rapid recolonization of most of the previously abandoned areas at the beginning of the Holocene and a remarkable increase in records during the Neolithic, a new gradual decrease of records is observed from the Neolithic to the Roman period, intensifying from c. 2000 years ago onwards and ending with the final disappearance of the species from south‐western France and north‐eastern Iberia. This second decline is linked to the aridification of the Mediterranean entourage that started in the mid‐Holocene and has been enhanced by human modification of the landscape. The species is shown to be sensitive to climate change.

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Palynology of the northwestern Mediterranean shelf (Gulf of Lions): First vegetational record for the last climatic cycle

Cited by 20 publications

References 41 publications

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

Quaternary "Compound" Incised Valley In A Microtidal Environment, Roussillon Continental Shelf, Western Gulf of Lions, France

Documenting the biogeographic history ofMicrotus cabreraethrough its fossil record

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