Paleoecological and stratigraphic controls on eurypterid Lagerstätten: a model for preservation in the mid-Paleozoic

Paleobiology ◽  
2017 ◽  
Vol 43 (3) ◽  
pp. 383-406 ◽  
Author(s):  
Matthew B. Vrazo ◽  
Carlton E. Brett ◽  
Samuel J. Ciurca
Keyword(s):  
Lower Devonian ◽  
Abiotic Conditions ◽  
Sequence Stratigraphic ◽  
Exceptional Preservation ◽  
Microbial Structures ◽  
Subaerial Exposure ◽  
Stratigraphic Framework ◽  
The World ◽  
Long Term Preservation

AbstractRecent studies of eurypterid paleoecology suggest that formation of eurypterid Lagerstätten in the mid-Paleozoic of Laurentia was controlled by the presence of an ecological–taphonomic window that recurred predictably in nearshore, marginal environments during transgressions. We tested this hypothesis by performing a high-resolution taxonomic, environmental, and stratigraphic survey and quantitative analysis of all Silurian–Lower Devonian eurypterid-bearing intervals in the Appalachian basin, the most prolific region for eurypterid remains in the world. Canonical correspondence analysis of sedimentological and faunal associations revealed a strong lithologic gradient between groupings of eurypterid genera and associated taxa across the basin, and a significant association of eurypterids with microbialites (thrombolites, stromatolites) and evaporitic structures. Field observations confirmed that, stratigraphically, eurypterids in the basin frequently occur above the microbialite structures and beneath evaporites and other indicators of increased salinity or subaerial exposure. Following interpretation of these features within a sequence stratigraphic framework, we present a preservational model in which (1) eurypterids inhabited nearshore settings following freshening conditions concomitant with minor transgressions, (2) their remains were subsequently buried by storms or microbialite sediment baffling, and (3) subsequent long-term preservation of tissues was facilitated by regression and cyclical shallowing-up successions that promoted hypersalinity and anoxia. In the central and southern region of the basin, where microbial structures and evidence for hypersalinity are less common, a similar pattern of cyclical shallowing-upward deposition within eurypterid-bearing units holds. Thus, eurypterid preservation appears to reflect a combination of ecological preferences and abiotic conditions that promoted inhabitation and eventual preservation within the same setting. This study provides the first quantitative support for a sea level–based control on preservation of eurypterids and adds to the growing body of evidence that suggests that analysis of exceptional preservation in the fossil record benefits from interpretation within a sequence stratigraphic framework.

scholarly journals Stratigraphy of the Anthropocene

2011 ◽  
Vol 369 (1938) ◽  
pp. 1036-1055 ◽  
Author(s):  
Jan Zalasiewicz ◽  
Mark Williams ◽  
Richard Fortey ◽  
Alan Smith ◽  
Tiffany L. Barry ◽  
...  
Keyword(s):  
Sediment Flux ◽  
Relative Timing ◽  
Sequence Stratigraphic ◽  
The Earth ◽  
Time Space ◽  
Marine Realm ◽  
Physical And Chemical ◽  
The Impact ◽  
Long Term Preservation

The Anthropocene, an informal term used to signal the impact of collective human activity on biological, physical and chemical processes on the Earth system, is assessed using stratigraphic criteria. It is complex in time, space and process, and may be considered in terms of the scale, relative timing, duration and novelty of its various phenomena. The lithostratigraphic signal includes both direct components, such as urban constructions and man-made deposits, and indirect ones, such as sediment flux changes. Already widespread, these are producing a significant ‘event layer’, locally with considerable long-term preservation potential. Chemostratigraphic signals include new organic compounds, but are likely to be dominated by the effects of CO 2 release, particularly via acidification in the marine realm, and man-made radionuclides. The sequence stratigraphic signal is negligible to date, but may become geologically significant over centennial/millennial time scales. The rapidly growing biostratigraphic signal includes geologically novel aspects (the scale of globally transferred species) and geologically will have permanent effects.

High Resolution Sequence Stratigraphy of Silurian Strata in Tazhong Area

2013 ◽  
Vol 734-737 ◽  
pp. 111-116
Author(s):  
Lei Zhang ◽  
Lun Wei Zhu ◽  
Xue Juan Zhang
Keyword(s):  
High Resolution ◽  
Sequence Stratigraphy ◽  
Third Order ◽  
Sequence Stratigraphic ◽  
Stratigraphic Framework ◽  
Tazhong Area ◽  
Sequence Boundaries ◽  
High Resolution Sequence Stratigraphy ◽  
Comprehensive Study

According to the fundamental principles of high resolution sequence stratigraphy, this paper focused on the application of high resolution sequence stratigraphy to Silurian strata in Tazhong area. Based on the comprehensive study of logging, drilling and seismic information, the high resolution sequence boundaries of Silurian strata and two scales of datum level cycles (long-term and intermediate-term) can be recognized in Tazhong area. Seven chronstratigraphic boundaries can be recognized in Silurian strata, including four sequence boundaries, which were the transformation from datum level falling to datum level rising, and three flooding surfaces, which the transformation from datum level rising to datum level falling. The Silurian strata in Tazhong area can be divided into three third-order sequences which correspond to three long-term datum level cycles, and 11 fourth-order sequences (parasequence sets) relating to 11 intermediate-term datum level cycles. The classification aforementioned can much better solved the corresponding problem between the six lithological sections of Silurian strata and sequence formations, finally establishes the high resolution sequence stratigraphic framework of Silurian strata in Tazhong area.

scholarly journals Cryopreservation and transplantation of common carp spermatogonia

2018 ◽  
Author(s):  
Roman Franěk ◽  
Zoran Marinović ◽  
Jelena Lujić ◽  
Béla Urbányi ◽  
Michaela Fučíková ◽  
...  
Keyword(s):  
Common Carp ◽  
Sperm Cryopreservation ◽  
Post Transplantation ◽  
Wide Range ◽  
Cultured Fish ◽  
The World ◽  
Exogenous Origin ◽  
Long Term Preservation ◽  
Surrogate Production

AbstractCommon carp (Cyprinus carpio) is one of the most cultured fish species over the world with many different breeds and plenty of published protocols for sperm cryopreservation, however, data regarding preservation of gonadal tissue and surrogate production is still missing. A protocol for freezing common carp spermatogonia was developed through varying different factors along a set of serial subsequent experiments. Among the six cryoprotectants tested, the best survival was achieved with dimethyl sulfoxide (Me2SO). In the next experiment, a wide range of cooling rates (0.5–10 °C/min) and different concentrations of Me2SO were tested resulting in the highest survival using 2 M Me2SO and cooling rate of –1 Q59 A When testing different tissue sizes and incubation times in the cryomedium, the highest viability was observed when incubating 100 mg tissue fragments for 30 min. Finally, sugar supplementation did not yield significant differences. When testing different equilibration (ES) and vitrification solutions (VS) used for needle-immersed vitrification, no significant differences were observed between the tested groups. Additionally, varied exposure time to VS did not improve the vitrification outcome where the viability was 4-fold lower than that of freezing. The functionality of cryopreserved cells was tested by interspecific transplantation into sterilized goldfish recipients. The exogenous origin of the gonads in goldfish recipients was confirmed by molecular markers and incorporation rate was over 40% in both groups at 3 months post transplantation. Results of this study can serve as an alternative way for long-term preservation of germplasm in carp which can be recovered in a surrogate recipient.

Preservation and Access to Digital Materials

2018 ◽  
pp. 150-174
Author(s):  
Trywell Kalusopa
Keyword(s):  
Literature Review ◽  
Learning Curve ◽  
Policy Options ◽  
African Countries ◽  
Digital World ◽  
Collaborative Strategies ◽  
The World ◽  
Developed World ◽  
Long Term Preservation

As the digital world unfolds, Africa continues to grapple with the issues of preservation and access of digital materials. This chapter demonstrates through a systematic literature review how Africa could learn from other efforts in the world to develop and guide their own strategic and policy options to deal with issues of preservation and access of digital materials. The chapter reviews literature on global or universal collaborative strategies and efforts on digital preservation initiated in the developed world as a learning curve for Africa. The current challenges of national and institutional capacities regarding the preservation of digital materials in selected African countries that have made some visible efforts and impact are also discussed. The chapter then makes several recommendations on the strategic and policy options for improving the state of material preservation, human and material requirements in order to improve the long-term preservation, and standards for the longer-term usability and interoperability of digital materials in Africa.

scholarly journals The Homogocene: a research prospectus for the study of biotic homogenisation

NeoBiota ◽  
2018 ◽  
Vol 37 ◽  
pp. 23-36 ◽  
Author(s):  
Julian D. Olden ◽  
Lise Comte ◽  
Xingli Giam
Keyword(s):  
Global Change ◽  
Biological Diversity ◽  
Significant Progress ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Conservation Implications ◽  
The World ◽  
Biotic Homogenisation ◽  
Long Term Preservation

In an era of global change, the process of biotic homogenisation by which regional biotas become more similar through time has attracted considerable attention from ecologists. Here, a retrospective look at the literature is taken and the question asked how comprehensive is the understanding of this global phenomenon? The goal is to identify potential areas for additional and future enquiries to advance this research frontier and best ensure the long-term preservation of biological diversity across the world. Six propositions are presented here to; (1) broaden our geographic and taxonomic understanding, (2) diversify the spatial and temporal scales of inquiry, (3) reconcile past and embrace new approaches to quantification, (4) improve our knowledge of the underlying drivers, (5) reveal the conservation implications and (6) forecast future homogenisation. It is argued that significant progress in the understanding of the causes, consequences and conservation implication of biotic homogenisation will come by integrating concepts and approaches from ecology, evolution and conservation across a hierarchy of spatial and temporal scales.

The Research of High-Resolution Sequence Stratigraphy of Putaohua Reservoir in Daan Oilfield

2013 ◽  
Vol 838-841 ◽  
pp. 1843-1846
Author(s):  
Ting Ting Li ◽  
Yue Shi ◽  
You Hai Sun ◽  
Ming Qin
Keyword(s):  
High Resolution ◽  
Sequence Stratigraphy ◽  
Geophysical Data ◽  
Short Term ◽  
Middle Term ◽  
Sequence Stratigraphic ◽  
Stratigraphic Framework ◽  
Basic Characteristics ◽  
High Resolution Sequence Stratigraphy

By using geological and geophysical data and according to the basic characteristics of sequence boundary, Putaohua Reservoir in Daan Oilfield is divided into a rise hemicycle in long-term cycles, a full middle-term cycle, nine short-term cycles and a number of ultra-short-term cycles.The high-resolution sequence stratigraphic framework of Putaohua reservoir under monosandbody rank is established, and a set of techniques and methods to high-resolution sequence stratigraphy correlation in shallow delta is summed up.

Preservation and Access to Digital Materials

2018 ◽  
pp. 447-471
Author(s):  
Trywell Kalusopa
Keyword(s):  
Literature Review ◽  
Learning Curve ◽  
Policy Options ◽  
African Countries ◽  
Digital World ◽  
Collaborative Strategies ◽  
The World ◽  
Developed World ◽  
Long Term Preservation

As the digital world unfolds, Africa continues to grapple with the issues of preservation and access of digital materials. This chapter demonstrates through a systematic literature review how Africa could learn from other efforts in the world to develop and guide their own strategic and policy options to deal with issues of preservation and access of digital materials. The chapter reviews literature on global or universal collaborative strategies and efforts on digital preservation initiated in the developed world as a learning curve for Africa. The current challenges of national and institutional capacities regarding the preservation of digital materials in selected African countries that have made some visible efforts and impact are also discussed. The chapter then makes several recommendations on the strategic and policy options for improving the state of material preservation, human and material requirements in order to improve the long-term preservation, and standards for the longer-term usability and interoperability of digital materials in Africa.

scholarly journals A Review on the Historical Development of Environmental Specimen Banks

2018 ◽  
Vol 38 ◽  
pp. 01016
Author(s):  
Yu Xin Luo
Keyword(s):  
Historical Development ◽  
Environmental Studies ◽  
Current Status ◽  
Environmental Specimen ◽  
The World ◽  
Long Term Preservation ◽  
Monitoring Practice ◽  
Environmental Specimen Banks

Environmental Specimen Banks (ESBs) are facilities that archive samples from the environment for future researching and monitoring purposes. In addition, the long-term preservation of representative specimens is an important complement to environmental studies and monitoring practice. This article presented detailed information about ESBs in the world, and reviewed the history and current status of ESBs in China. Besides, crucialshould leave 8 mm of space above the abstract and 10 mm after the abstract.

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