Synchronous palynological changes in early pleistocene sediments off new jersey and Iberia, and a possible paleoceanographic explanation

32Dinoflagellates constitute a large proportion of the planktonic biomass from marine to 33 freshwater environments. Some species produce a preservable organic-walled resting cyst 34 (dinocyst) during the sexual phase of their life cycle that is an important link between the 35 organisms, the environment in which their parent motile theca grew, and the sedimentary 36 record. Despite their abundance and widespread usage as proxy indicators for environmental 37 conditions, there is a lack of knowledge regarding the dinocyst wall chemical composition. It 38 is likely that numerous factors, including phylogeny and life strategy, determine the cyst wall 39 chemistry. However, the extent to which this composition varies based on inherent 40 (phylogenetic) or variable (ecological) factors has not been studied.

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“…, McCarthy et al. , Versteegh et al. ), although it is likely not a straightforward process (Reichart and Brinkhuis ).…”

Section: Resultsmentioning

confidence: 99%

Differences in the chemical composition of organic‐walled dinoflagellate resting cysts from phototrophic and heterotrophic dinoflagellates

Bogus

Mertens

Lauwaert

et al. 2014

Journal of Phycology

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“…At present, maximum velocity of the Gulf Stream is between 1.5 and 2.0 m s −1 (Rapp & Smith, 1994;Perkovic et al, 2004). The velocity of the Gulf Stream pulses through time, with velocities increasing during glacial periods (Kaneps, 1979;McCarthy et al, 2000) but declining to zero when the conveyor current shuts down completely (Broecker, 1991(Broecker, , 1997. The increase in velocity may have more to do with vastly shortening the route of the gyre.…”

Section: Discussionmentioning

confidence: 99%

Periodicity of extinction and recolonization of the West Indian topshellCittarium picain the Quaternary of Bermuda (Gastropoda: Trochoidea)

Olson

Hearty

2013

Biol J Linn Soc Lond

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Hermit‐crab transported shells of the West Indian top shell Cittarium pica occur in numerous terrestrial fossil deposits on Bermuda, which is the most remote outpost of this Caribbean species. Cittarium is so far known only from deposits of interglacial ages corresponding to marine isotope stages (MIS) 11, 9, 5e, and 1 (Holocene). In at least the cases of MIS 11 and 5e, Cittarium appears at the very beginning of the interglacial. The species is definitely absent from well‐stratified cave deposits of the last glacial (MIS 4–2). It is hypothesized that colder sea‐surface temperatures (SSTs) during glacial periods caused Cittarium to be extirpated on Bermuda, and that it has made at least four independent colonizations of the island in the past 400 000 years. Because of the limited larval life of Cittarium, the window for colonization may be a very narrow period at the onset of interglacials when the SST has risen sufficiently to make Bermuda habitable but the velocity of the Gulf Stream is still sufficiently rapid to transport viable larvae from the Bahamas. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 235–243.

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“…Dinoflagellate cysts are, in general, relatively resistant to degradation due to the structure of the cyst wall (e.g., Kokinos et al, 1998;Gélinas et al, 2001; de Leeuw et al, 2006;Zonneveld et al, 2008;Versteegh et al, 2012). However, it is known from laboratory (e.g., Dale, 1976;Hopkins and Mc-Carthy, 2002) and field experiments (e.g., as well as sediments (e.g., Zonneveld et al, 1997;McCarthy et al, 2000) that P-cysts are more quickly oxidized relative to the G-cysts. In both the OMZ transect and the below-OMZ-seep, the G/P ratio increases by 75 % and 66 %, respectively (Fig.…”

Section: G/p Ratiomentioning

confidence: 99%

“…In order to determine whether this degradation is selective, we incorporate them into indices with related refractory compounds, such as pristane and phytane, cholestanol, and dinostanone and dinosterone, respectively (after Nishimura and Koyama, 1977;McCaffrey et al, 1991;Mouradian et al, 2007). Another proxy for illustrating changes in export production is the ratio between gonyaulacoid and peridinioid organic-walled dinoflagellate resting cysts (e.g., Harland, 1973;McCarthy et al, 2000). However, the gonyaulacoid species are more resistant to aerobic degradation than the peridinioid species, which are sensitive to oxygen exposure (e.g., Zonneveld et al, 1997Zonneveld et al, , 2001Combourieu-Nebout et al, 1998;Versteegh and Zonneveld, 2002).…”

Section: Introductionmentioning

confidence: 99%

The effect of meter-scale lateral oxygen gradients at the sediment-water interface on selected organic matter based alteration, productivity and temperature proxies

Bogus¹,

Zonneveld²,

Fischer³

et al. 2011

Preprint

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A valid assessment of selective aerobic degradation on organic matter (OM) and its impact on OM-based proxies is vital to produce accurate environmental reconstructions. However, most studies investigating these effects suffer from inherent environmental heterogeneities. This includes differences in the initial OM composition, as a result of variable upper water column conditions, or from those induced by selective aerobic degradation. In this study, we used surface samples collected along two meter-scale transects and one longer transect in the northeastern Arabian Sea to constrain initial OM heterogeneity, in order to evaluate selective aerobic degradation on temperature, productivity and alteration indices at the sediment-water interface. All of the alteration indices, the higher plant alkane index, alcohol preservation index, and diol oxidation index, demonstrated that they are sensitive indicators for changes in oxygen content at the sediment-water interface. The export production indices, a cholesterol-based stanol/stenol and dinoflagellate lipid- and cyst-based ratios, showed significant (more than 20%) change over the lateral oxygen gradients. Therefore, they do not exclusively reflect surface water productivity, but can be altered after deposition with varying oxygen content at the sediment-water interface. Two of the investigated proxies, the glycerol dibiphytanyl glycerol tetraethers (GDGT) based TEX86 sea surface temperature indices and a productivity index based on phytol, phytane and pristane, did not show any trends related to oxygen concentration at the sediment-water interface. Nevertheless, unrealistic sea surface temperatures were obtained after application of the TEX86, TEX86L, and TEX86H proxies. The phytol-based ratios were likely modified by the sedimentary production of pristane. Our results demonstrate the rapid and selective impact of aerobic organic matter degradation on the lipid and palynomorph composition of surface sediments on a small spatial scale and suggests useful tracers of changing redox conditions along the sediment-water interface

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Synchronous palynological changes in early pleistocene sediments off new jersey and Iberia, and a possible paleoceanographic explanation

Cited by 4 publications

References 19 publications

Differences in the chemical composition of organic‐walled dinoflagellate resting cysts from phototrophic and heterotrophic dinoflagellates

Differences in the chemical composition of organic‐walled dinoflagellate resting cysts from phototrophic and heterotrophic dinoflagellates

Periodicity of extinction and recolonization of the West Indian topshellCittarium picain the Quaternary of Bermuda (Gastropoda: Trochoidea)

The effect of meter-scale lateral oxygen gradients at the sediment-water interface on selected organic matter based alteration, productivity and temperature proxies

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