<i>Trochosira polychaeta</i>: a colonial diatom from the late Cretaceous exhibiting two contrasting chain-linking mechanisms and a wide range of preservation

Kemp, Alan E. S.; Davies, Andrew; Pearce, Richard

doi:10.1080/0269249x.2014.999130

Cited by 3 publications

(5 citation statements)

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“…The almost total lack of fragmentation and pelletisation further indicates direct settling from surface blooms or concentrations, mainly unmediated by zooplankton ingestion and pelletisation. Only at the finest level is there evidence for variable preservation of some of the most delicate structures in different laminae, for example cingula and the processes that link chains, and this is attributed to dissolution in the water column related to varying levels of dissolved silica (Kemp et al, 2015). The preservation of laminae suggests an anoxic environment devoid of epifaunal or infaunal activity and there is no evidence of postdepositional disruption.…”

Section: Taphonomymentioning

confidence: 99%

“…T. polychaeta is geographically widespread (Strelnikova, 1971;Hajós and Stradner, 1975;Dell'Agnese and Clark, 1994;Tapia and Harwood, 2002), suggesting it is likely to have been a planktonic species. Valves are commonly linked with robust central linking spines (Sims, 1988), but also with complex marginal structures (Kemp et al, 2015) allowing the formation of chains (Fig. 5F).…”

Section: Trochosira Glesermentioning

confidence: 99%

“…Kitchell et al, 1986;Dell'Agnese and Clark, 1994). However the range of delicate features and occurrence in chains clearly indicate a vegetative cell status (see Kemp, et al 2015 for a full discussion). Its concurrent sedimentation with Hemiaulus within the vegetative laminae of the CESAR 6 suggests it is likely that they shared the same ecological niche of adaptation to growth during the summer stratification.…”

Section: Trochosira Glesermentioning

confidence: 99%

“…It is a lamina-forming genus in the CESAR 6. Unusually for the CESAR 6 diatoms, T. polychaeta shows a range of wide range of preservation that is interpreted to result from dissolution within the water column, and not post depositionally (Kemp et al, 2015). The relatively robust appearance of T. polychaeta in some states of preservation led some authors to interpret it as a resting spore (e.g.…”

Section: Trochosira Glesermentioning

confidence: 99%

“…Furthermore, this feature is common to genera ranging from neritic (Paralia) to fully pelagic (Hemiaulus). The excellent preservation of linking structures has also facilitated an appraisal of their evolution (Kemp et al, 2015). …”

mentioning

confidence: 99%

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Late Cretaceous seasonal palaeoclimatology and diatom palaeoecology from laminated sediments

Davies

Kemp

2016

Cretaceous Research

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Laminated diatom-rich marine sediments from California and the Arctic Ocean provide a window into the seasonal climate and oceanography of the mid-and high-latitude Late Cretaceous. These remarkable shallow-buried sediments constitute palaeo-sediment traps that record exceptionally well-preserved sequential biogenic and lithogenic flux events. Many of the diatom laminae are composed of a few dominant taxa, and we use a species-based approach for palaeoecological interpretation. Contrary to many earlier interpretations, results indicate that both sites preserve a major flux of taxa adapted to exploit a strongly stratified ocean. The uppermost Maastrichtian Marca Shale of California records a seasonal cycle initiated with a spring bloom flux of diatom resting spores followed by a summer lithogenic sediment input likely driven by monsoonal storms providing river runoff and aeolian input. This is followed by a dominant diatom flux of species that thrived in the summer stratification in deep chlorophyll maxima and were sedimented in the fall when this stratification broke down. Dominant taxa comprising this group include Hemiaulus, Stephanopyxis, Stellarima and Rhizosolenia. The uppermost Campanian CESAR 6 core from the Arctic Alpha Ridge, records a spring bloom flux of resting spores followed by a more dominant summer and fall flux of diatom vegetative cells which were likely concentrated in subsurface summer blooms that generated a "summer export pulse" and by the breakdown of stratification in the fall that gave massive flux of deep chlorophyll maxima species in the fall dump. The dominance and diversity of Hemiaulus in the CESAR 6 core together with widespread evidence of N 2 -fixation may indicate that some diatom blooms were powered by intracellular N 2 -fixing cyanobacteria as in the modern oligotrophic ocean. Thin lenses of fine lithogenic sediment that occur mostly in the spring layer represent rafting by winter sea ice and support other evidence that suggests intermittent winter freezing in the Late Cretaceous Arctic.Keywords: Late Cretaceous; Diatom blooms; Paleoecology; California; Arctic; Sea Ice 3 1.Introduction Laminated pelagic and hemipelagic marine sediments often constitute "palaeosediment traps" that preserve sequential flux events from which the ancient seasonal flux cycle may be reconstructed. They commonly preserve both the biogenic flux events from surface ocean productivity and also the terrigenous sediment input common in hemipelagic or marginal settings. Within rare, exceptionally well-preserved Cretaceous sediments, fossil diatom algae record the seasonal cycle of marine production and flux to the sea bed. In the modern ocean diatom algae are the dominant, bloom-forming phytoplankton in many environments and are key players in the marine biological carbon pump. The relative contribution of diatoms to total primary production has been estimated to range from 35% in the oligotrophic oceans to 75% in the coastal zone and in the Antarctic (Nelson et al., 1995), while their contribution...

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Section: Taphonomymentioning

confidence: 99%

Section: Trochosira Glesermentioning

confidence: 99%

Section: Trochosira Glesermentioning

confidence: 99%

Section: Trochosira Glesermentioning

confidence: 99%

mentioning

confidence: 99%

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Late Cretaceous seasonal palaeoclimatology and diatom palaeoecology from laminated sediments

Davies

Kemp

2016

Cretaceous Research

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On Light and Diatoms: A Photonics and Photobiology Review

Ghobara

Mazumder

Vinayak

et al. 2019

Diatoms: Fundamentals and Applications

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Regulation of chain length in two diatoms as a growth-fragmentation process

et al. 2016

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Chain formation in diatoms is relevant because of several aspects of their adaptation to the ecosystem. However, the tools to quantify the regulation of their assemblage and infer specific mechanisms in a laboratory setting are scarce. To address this problem, we define an approach based on a statistical physics model of chain growth and separation in combination with experimental evaluation of chain-length distributions. Applying this combined analysis to data from Chaetoceros decipiens and Phaeodactylum tricornutum, we find that cells of the first species control chain separation, likely through a cell-to-cell communication process, while the second species only modulates the separation rate. These results promote quantitative methods for characterizing chain formation in several chain-forming species and in diatoms in particular.

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Trochosira polychaeta: a colonial diatom from the late Cretaceous exhibiting two contrasting chain-linking mechanisms and a wide range of preservation

Cited by 3 publications

References 25 publications

Late Cretaceous seasonal palaeoclimatology and diatom palaeoecology from laminated sediments

Late Cretaceous seasonal palaeoclimatology and diatom palaeoecology from laminated sediments

On Light and Diatoms: A Photonics and Photobiology Review

Regulation of chain length in two diatoms as a growth-fragmentation process

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