Miscellaneous papers by Jeremy R Young
The Longobucco Group is a cover sequence of Liassic sediments recording rifting of Hercynian crys... more The Longobucco Group is a cover sequence of Liassic sediments recording rifting of Hercynian crystalline basement. Within turbidites of the upper part of this sequence are numerous olistoliths, up to 250 m long. These are not parts of olistostromes, or other mass movement deposits, but appear to have travelled into the basin independently; hence the term 'isolated olistolith' seems appropriate for them. Soft-sediment deformation structures around the margins of one well-exposed olistolith suggest an analogy with'outrunner-blocks' recently described from a modern submarine slope-failure complex by . In both cases the blocks appear to have travelled considerable distances across very low slopes without disturbing the underlying sediments to any great extent. Transport probably occurred relatively rapidly with the aid of overpressuring of the underlying sediments.
Haptophytes are represented in the fossil record by a phenomenal abundance of coccoliths and cryp... more Haptophytes are represented in the fossil record by a phenomenal abundance of coccoliths and cryptic nannoliths. The biological information available from this record is outlined here. In particular palaeontological perspectives on coccolith based taxonomy and phylogenetic inferences are described. It is shown that the geological record of coccoliths is selective, but very complete for the selected species. Research on exceptionally preserved fossil coccoliths, the Cretaceous/ Tertiary boundary, palaeoceanography, and Milankovitch cyclicity is outlined.
BioScience, 2011
Natural history collections (NHCs) are an important source of the long-term data needed to unders... more Natural history collections (NHCs) are an important source of the long-term data needed to understand how biota respond to ongoing anthropogenic climate change. These include taxon occurrence data for ecological modeling, as well as information that can be used to reconstruct mechanisms through which biota respond to changing climates. The full potential of NHCs for climate change research cannot be fully realized until high-quality data sets are conveniently accessible for research, but this requires that higher priority be placed on digitizing the holdings most useful for climate change research (e.g., whole-biota studies, time series, records of intensively sampled common taxa). Natural history collections must not neglect the proliferation of new information from efforts to understand how present-day ecosystems are responding to environmental change. These new directions require a strategic realignment for many NHC holders to complement their existing focus on taxonomy and systematics. To set these new priorities, we need strong partnerships between NHC holders and global change biologists.
Trends in ecology & evolution, 2011
In the otherwise excellent special issue of Trends in Ecology and Evolution on long-term ecologic... more In the otherwise excellent special issue of Trends in Ecology and Evolution on long-term ecological research (TREE 25(10), 2010), none of the contributors mentioned the importance of natural history collections (NHCs) as sources of data that can strongly complement past and ongoing survey data. Whereas very few field surveys have operated for more than a few decades, NHCs, conserved in museums and other institutions, comprise samples of the Earth's biota typically extending back well into the nineteenth century and, in some cases, before this time. They therefore span the period of accelerated anthropogenic habitat destruction, climate warming and ocean acidification, in many cases reflecting baseline conditions before the major impact of these factors.
Papers by Jeremy R Young
Handbook for the Analysis of Micro-Particles in Archaeological Samples, 2020
Taxonomy and morphology of Calciopappus curvus sp. nov. (Syracosphaeraceae, Prymnesiophyceae), a novel appendage-bearing coccolithophore
Protist, Oct 1, 2023
<i>Gladiolithus adeyi</i> sp. nov.: a new deep photic coccolithophore species and new molecular genetic and crystallographic observations on <i>Gladiolithus flabellatus.</i>
Cryptogamie Algologie, Nov 1, 2014
Jomonlithus littoralis is a coccolithophore exhibiting unusual coccolith morphology that has prev... more Jomonlithus littoralis is a coccolithophore exhibiting unusual coccolith morphology that has previously only been reported from Japanese coastal waters. Jomonlithus is a mono-specific genus that has remained incertae sedis within the Prymnesiophyceae since its original description. We isolated a culture of the calcifying (diploid) stage of this species from Mediterranean coastal waters that subsequently produced a non-calcifying life cycle stage in culture. The non-calcifying (haploid) stage of J. littoralis is described for the first time through light and electron microscope observations of cytology, scale ornamentation and ultrastructure. A 28s rDNA molecular phylogeny is presented and the systematic affinities of Jomonlithus are discussed. This genus is placed in the Hymenomonadaceae and the diagnosis of this family is emended.
Some proposed changes to the systematics of Cenozoic and Mesozoic nannoplankton
(Appendix B) Age model of ODP Hole 108-662A from the equatorial Atlantic
Notes on nannoplankton systematics and life-cycles - <i>Ceratolithus cristatus, Neosphaera coccolithomorpha </i>and <i>Umbilicosphaera sibogae</i>
Coccolithophores are beautiful organisms and also important ones. They are one of the main groups... more Coccolithophores are beautiful organisms and also important ones. They are one of the main groups of marine phytoplankton playing key roles in the marine ecosystem as primary producers and in marine biogeochemistry as producers of organic carbon, carbonate and dimethyl sulphide. In addition they are major sediment formers, key biostratigraphic marker fossils and valuable indicators of palaeoceanographic change. These diverse interests have lead to intensive research on extant coccolithophores over the past decade. Interdisciplinary research has been promoted through the European projects EHUX (Coccolithophorid Dynamics: The European Emiliania huxleyi Programme) and CODENET (Coccolithophorid Evolutionary Biodiversity and Ecology Network) projects. In addition there has been extensive work, especially in Europe and Japan, on coccolithophore communities in the plankton and on fluxes of coccoliths in sediment traps. As a result of this recent research the taxonomy of coccolithophores has advanced significantly over the past decade, i.e. since the seminal syntheses of and Jordan et al. (1994). So there is a need for a new synthesis, and especially for an identification guide. There is still work to be done, especially formal description of many now well-established informally described species, but coccolithophores are now one of the most comprehensively described, and most reliably identifiable groups of oceanic microplankton. In consequence they are an ideal group for developing study of the pattern and role of biodiversity in plankton ecology. We hope this identification guide will facilitate such studies, as well as informing palaeontologists studying fossil coccoliths of the nature of the modern biota. Table of content.
Narrow-rimmed placoliths: a distinctive group of deep photic coccolithophores?
Some emendments to calcareous nannoplankton taxonomy
Proposed changes to the classification system of living Coccolithophorids
Volume calculation of Cretaceous calcareous nannofossils
Volume estimates are calculated for common mid-Cretaceous nannofossils, using a methodology previ... more Volume estimates are calculated for common mid-Cretaceous nannofossils, using a methodology previously developed from studies of extant nannoplankton. The range of volume variation within this group is highlighted, and the potential of such estimates for giving new insights into palaeoecological and palaeoceanographic studies is outlined. Introduction Nannofossils vary in linear size by about an order of magnitude, consequently they vary in volume by about three orders of magnitude, i.e. 1000-fold. In traditional palaeoecological analyses, this variation is ignored, however, there is obviously potential for investigating whether volume-calibrated census-data may yield more meaningful data, especially for studies of carbonate formation. Several estimates of the volume of extant coccoliths have been published, primarily to allow conversion of coccolith fluxes into carbonate fluxes (Paasche, 1962; Honjo, 1976; Samtleben & Bickert, 1990; Faggerbakke et al., 1994; Beaufort & Heussner, 1999; Young & Ziveri, 2000). These estimates are being widely used in sediment-trap studies (e.g. Broerse, 2000; Sprengel, 2000). The purpose of this paper is to produce estimates of the volume and mass of the most abundant calcareous nannofossils of the mid-Cretaceous (Barremian-Albian). From these estimates, the amount of CaC0 3 produced by coccoliths during interpreted eutrophic and oligotrophic conditions will, subsequently, be estimated (Tremolada & Erba, in prep.). It is hoped that this will provide a new approach to the study of a key time-interval which was affected by some of the strongest perturbations of Earth's history: in particular, the widespread deposition of black shales, and the associated Oceanic Anoxic Events, are characteristic of this age. There have previously been only a few estimates of the volume of Mesozoic nannofossils. Williams & Bralower (1995) proposed an 'averaged Cretaceous nannofossil' with a volume of 14flm• In the study ofMattioli & Pittet (2002), analyses were mostly performed on the Jurassic nannolith, Schizosphaerella punctulata. The present work represents the first attempt to investigate the significance of volume variation within Cretaceous nannofloras . Material and methods The best-preserved samples available were investigated in order to determine the average dimensions of the most abundant mid-Cretaceous nannofossils. Samples from ODP Legs 185 (Marianne-Bonin Trench) and 171 (Blake Nose), and DSDP Leg 62 (Mid-Pacific Mountains) were studied, along with some outcrop samples from the Tethyan area. The interpreted oligotrophic assemblages are dominated by Watznaueria barnesiae, Nannoconus spp., Zeugrhabdotus embergeri and Rhagodiscus asper, whereas interpreted eutrophic assemblages are characterised by high abundances of Zeugrhabdotus erectus, Discorhabdus rotatorius, Biscutum constans and Zeugrhabdotus spp. (interpreted after, e.g., Erba, 1992; Erba et al., 1992; Erba, 1994). As noted by Young & Ziveri (2000), the volume function for any given shape is of the form V=K, * 1, where K, is a constant depending on the shape, and I is a characteristic dimension. Thus, there are essentially two steps to determining nannofossil volume, frrst size analysis, to determine average size, second shape analysis, to determine K, Since volume is proportional to length cubed, accurate size determination is critical. For size determination, images of coccoliths and nannoliths were collected using a digital image-capture system (Young et al., 1996) at 1600x and 1250x magnification, then the dimensions were measured using the software NIH-Image, adapted for nannoplankton analyses. For each taxon, at least 250 specimens were measured to provide accurate size estimates. For shape analysis, two approaches were used. For coccoliths and nannoconids, the NIH-Image macro program, described by Young & Ziveri (2000), was used to calculate volumes of rotation from cross-sections. Given a digitised cross-section and an axial ratio as inputs, the program measures and displays thickness as a function of distance from the axis of symmetry, calculates the implied volume, and displays the result. To produce cross-sections, mobile mounts were used in order to tilt individual specimens; images of these were captured. Outlines of the cross-sections were then traced in a graphics program and exported to NIH-Image for quantification. For geometric-shaped nannoliths (pentaliths, Assipetra infracretacea, etc.), volumes were calculated using appropriate mathematical formulae for average-sized specimens. K, values were then calculated. These K, values can be used to calculate volumes for populations of different average size. Results The results of the volume calculations are presented in Table 1. The following notes give details of the basis for the calculations. ·
A Net for the Construction of Model Calcite Rhombohedra
Coccolith polysaccharides: influence on genesis and diagenesis
<i>Scyphosphaera porosa</i> Kamptner 1967 rediscovered in the plankton
Coccolithophorid diversity in the genus <i>Polycrater</i> and possible relationships with other genera
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Miscellaneous papers by Jeremy R Young
Papers by Jeremy R Young