A stable isotope study of multiple species of planktonic foraminifera across sapropels of the Tyrrhenian Sea, ODP Site 974

Bernasconi, Stefano M.; Pika-Biolzi, Milena

doi:10.1016/s0031-0182(00)00054-7

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…The interruption of the time-equivalent sapropel interval has already been documented in other ODP sites from different water depths and hydrographic settings (Bernasconi & Pika-Biolzi, 2000;Hassold et al, 2003;Meyers & Arnaboldi, 2005;Meyers & Bernasconi, 2005). This means that the synchronous water cooling observed in this study corroborates well the hypothesis of Meyers & Arnaboldi (2005).…”

Section: Sapropel Interruptionsupporting

confidence: 88%

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Stefanelli

Capotondi

2008

J. Micropalaeontol.

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Foraminifera were investigated across the sapropel unit corresponding to insolation cycle 90 deposited in three different oceanographic and depositional settings of the Mediterranean Sea (Alboran Sea, South Adriatic Sea and Ionian Sea). The constant presence of benthic foraminifera throughout the sapropels at <2000 m water depth and their absence within the sapropel at greater depth (>3000 m) indicate that the severity of oxygen depletion at the time of sapropel onset increases with increasing water depth.Planktonic and benthic foraminiferal patterns also document an interruption during sapropel deposition, which allows for the recognition of two sapropel phases. In all basins, the short interruption appears to be related to climatic deterioration, which led to the break in stratification and, hence, to the re-oxygenation of bottom waters. Since the interruption of the time-equivalent sapropel intervals has been documented previously in other Mediterranean areas, these data support the recent theory that this interruption must have been a trans-Mediterranean phenomenon and that the interruption records a short excursion out of the periods of wet climate associated with precessional minima. J. Micropalaeontol. 27(1): 45-61, May 2008.

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Section: Sapropel Interruptionsupporting

confidence: 88%

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Stefanelli

Capotondi

2008

J. Micropalaeontol.

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“…The δ 13 C of Orbulina universa recorded is ∼ 1.88‰ (range: 1.7‰–1.9‰) in the marly limestones and 1.37‰ (range: 1.2‰–1.7‰) in the sapropelic marls. This feature, already noted by many authors [e.g., Bernasconi and Pika‐Biolzi , 2000], has been explained by a fertility increase through the input of nutrients into the photic zone.…”

Section: Resultsmentioning

confidence: 57%

“…Investigations from plankton tow data have shown that planktic foraminifera live vertically dispersed in the upper water column and that the depth range has a significant influence on the oxygen isotope composition of individual species [ Fairbanks and Wiebe , 1980]. The living species Orbulina universa is known to be an intermediate dwelling species [ Bernasconi and Pika‐Biolzi , 2000], whereas the living planktic foraminifer Globigerinoides spp. [ Erez and Honjo , 1981; Ravelo and Fairbanks , 1992] and its fossil analogs [ Pearson and Shackleton , 1995] are regarded as being shallow mixed‐layer dwellers.…”

Section: Discussionmentioning

confidence: 99%

Coccolith δ¹⁸O and alkenone records in middle Pliocene orbitally controlled deposits: High‐frequency temperature and salinity variations of sea surface water

Beltran

Rafélis

Minoletti

et al. 2007

Geochem Geophys Geosyst

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[1] The calcareous nannoplankton flora is strongly controlled by water masses and is sensitive to ambient nutrient levels. In consequence, fossil remains of calcareous nannoplankton are useful tools for paleoceanography. Although they are the major producers of carbonates in the pelagic realm, their use as a seawater d18 O recorder is not easy due to their small size and the difficulty in isolating them from the bulk carbonate. Using a granulometric separation technique (Minoletti et al., 2001), it is now possible to concentrate coccoliths in monospecific fractions. We applied this method on three precession cycles (insolation cycles i-288 to i-282) from the mid-Pliocene Punta Piccola section (South Sicily), which led to an almost pure Pseudoemiliana lacunosa fraction. It was then possible to measure the isotopic signatures (d 18 O and d 13 C) and alkenone unsaturation ratio on the same recorder: P. lacunosa. This permits a precise reconstruction of environmental conditions (temperature and salinity) that prevailed in the upper photic zone during the cyclic deposition of these sediments. Our data provide a clear confirmation that sapropelic marl formation occurred during a wetter climate compared to the deposition of the marly limestones. Moreover, these results point out that salinity variations are not, as previously thought, always the primary factor that controlled the deposition of these cyclic events. This study is a step forward in the utilization of calcareous nannoplankton isotopic records in paleoenvironmental reconstructions.Components: 7929 words, 7 figures, 3 tables.Keywords: Pliocene; sapropels; Mediterranean; stable isotopes; alkenone; calcareous nannofossils.Index Terms: 0473 Biogeosciences: Paleoclimatology and paleoceanography (3344, 4900).

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“…Sea salinity in BM39 sampling area is around 38 ‰ all the year [42,43] and was measured at 37.8 ‰ during sampling.…”

Section: Resultsmentioning

confidence: 99%

Physiologic and metabolic characterization of a new marine isolate (BM39) of Pantoea sp. producing high levels of exopolysaccharide

et al. 2013

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BackgroundMarine environments are the widest fonts of biodiversity representing a resource of both unexploited or unknown microorganisms and new substances having potential applications. Among microbial products, exopolysaccharides (EPS) have many physiological functions and practical applications. Since EPS production by many bacteria is too scarce for practical use and only few species are known for their high levels of production, the search of new high EPS producers is of paramount importance. Many marine bacteria, that produce EPS to cope with strong environmental stress, could be potentially exploited at the industrial level.ResultsA novel bacterium, strain BM39, previously isolated from sediments collected in the Tyrrhenian Sea, was selected for its production of very high levels of EPS. BM39 was affiliated to Pantoea sp. (Enterobacteriaceae) by 16S rRNA gene sequencing and biochemical tests. According to the phylogenetic tree, this strain, being quite far from the closest known Pantoea species (96% identity with P. agglomerans and P. ananatis) could belong to a new species. EPS production was fast (maximum of ca. 21 g/L in 24 h on glucose medium) and mainly obtained during the exponential growth. Preliminary characterization, carried out by thin layer and gel filtration chromatography, showed that the EPS, being a glucose homopolymer with MW of ca. 830 kDa, appeared to be different from those of other bacteria of same genus. The bacterium showed a typical slightly halophilic behavior growing optimally at NaCl 40 ‰ (growing range 0-100 ‰). Flow cytometry studies indicated that good cell survival was maintained for 24 h at 120 ‰. Survival decreased dramatically with the increase of salinity being only 1 h at 280 ‰. The biochemical characterization, carried out with the Biolog system, showed that MB39 had a rather limited metabolic capacity. Its ability, rather lower than that of P. agglomerans, was almost only confined to the metabolization of simple sugars and their derivatives. Few alcohols, organic acids and nitrogen compounds were partially used too.ConclusionsStrain BM39, probably belonging to a new species, due to its remarkable EPS production, comparable to those of known industrial bacterial producers, could be suggested as a new microorganism for industrial applications.

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A stable isotope study of multiple species of planktonic foraminifera across sapropels of the Tyrrhenian Sea, ODP Site 974

Cited by 11 publications

References 15 publications

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Coccolith δ¹⁸O and alkenone records in middle Pliocene orbitally controlled deposits: High‐frequency temperature and salinity variations of sea surface water

Physiologic and metabolic characterization of a new marine isolate (BM39) of Pantoea sp. producing high levels of exopolysaccharide

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A stable isotope study of multiple species of planktonic foraminifera across sapropels of the Tyrrhenian Sea, ODP Site 974

Cited by 11 publications

References 15 publications

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Foraminiferal response to the deposition of insolation cycle 90 sapropel in different Mediterranean areas

Coccolith δ18O and alkenone records in middle Pliocene orbitally controlled deposits: High‐frequency temperature and salinity variations of sea surface water

Physiologic and metabolic characterization of a new marine isolate (BM39) of Pantoea sp. producing high levels of exopolysaccharide

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Coccolith δ¹⁸O and alkenone records in middle Pliocene orbitally controlled deposits: High‐frequency temperature and salinity variations of sea surface water