scholarly journals Review of the Ordovician rhynchonelliformean Brachiopoda of the East Baltic: their distribution and biofacies

2003 ◽  
Vol 50 ◽  
pp. 29-43
Author(s):  
Linda Hints ◽  
David A.T. Harper
Keyword(s):  
Sensu Stricto ◽  
Taxonomic Composition ◽  
Black Shales ◽  
Sea Level Changes ◽  
Low Diversity ◽  
Different Types ◽  
Time Changes ◽  
Brachiopod Fauna ◽  
The Baltic ◽  
Hirnantia Fauna

Analyses of the distribution, in time and space, of approximately 300 Ordovician rhynchonelliformean brachiopods in the East Baltic allow the development of a faunal template for the Baltic Province (sensu stricto) within the context of the European Realm. Two different brachiopod magnafacies, the upper and lower ramp associations, are monitored through time. Changes in the brachiopod fauna through uppermost Hunneberg to the Porkuni stages are demonstrated from different drill core sections and some bedrock exposures located in facially contrasting areas across the region. The main developmental trends within the brachiopod biofacies of the shallower part of the palaeobasin (North Estonian facies belt) are characterized by relatively continuous changes in taxonomic composition including the evolution of endemics and the establishment of relatively persistent associations, especially during the later Ordovician. In the deeper parts of the palaeobasin (Central Baltoscandian confacies belt including the Livonian Tongue) the several different types, clearly determined by changes in environment, occur: Relatively low diversity associations in the red-coloured sediments, a well-defined assemblage associated with black shales and more diverse associations in the argillaceous carbonate deposits. The appearance and distribution of some shortlived associations including immigrants to the Baltic (Dactylogonia and Rhynchotrema during the Keila-Oandu event, the Holorhynchus association during the mid-Ashgill and the Hirnantia fauna during the late Ashgill) are probably associated with climatic and sea-level changes in the palaeobasin.

First record of a Hirnantia Fauna from Spain, and its contribution to the Late Ordovician palaeogeography of northern Gondwana

1998 ◽  
Vol 89 (3) ◽  
pp. 187-197 ◽  
Author(s):  
E. Villas ◽  
S. Lorenzo ◽  
J. C. Gutiérrez-Marco
Keyword(s):  
Regional Development ◽  
Iberian Peninsula ◽  
First Record ◽  
Late Ordovician ◽  
Carnic Alps ◽  
Ciudad Real ◽  
Low Diversity ◽  
Brachiopod Fauna ◽  
Armorican Massif ◽  
Hirnantia Fauna

AbstractA new occurrence of the Hirnantia brachiopod fauna is documented from the Criadero Quartzite of Almadén, Ciudad Real Province, Spain. This unit is the regional development of a largely unfossiliferous sandy facies that frequently overlies the typical Late Ordovician diamictitic glaciomarine formations in the Iberian Peninsula and the Armorican Massif. The new occurrence establishes palaeontologically the latest Ashgill age of the quartzite, at least for its lowest horizons, and adds new data on a fauna that, although widespread, has been very rarely documented from peri-Gondwanan Europe. The new collection contains only Hirnantia sagittifera and Plectothyrella crassicosta chauveli. The subspecific status of the latter and its inclusion within Plectothyrella crassicosta is discussed herein, based on the continuous variation in rib thickness of several samples of both forms. The extremely low diversity and the occurrence of the key form P. c. chauveli, are both typical of the Bani Province that developed on the subpolar margins of Gondwana. This contrasts with other occurrences of the Hirnantia Fauna in peri-Gondwanan Europe, such as those from Sardinia and the Carnic Alps, which are characteristic of the more temperate Kosov Province.

scholarly journals Biopolymeric Materials Used as Nonviral Vectors: A Review

2021 ◽  
Vol 2 (1) ◽  
pp. 100-109
Author(s):  
Jailson de Araújo Santos ◽  
Daniel Barbosa Liarte ◽  
Alessandra Braga Ribeiro ◽  
Marcia dos Santos Rizzo ◽  
Marcília Pinheiro da Costa ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Web Of Science ◽  
Gene Transfection ◽  
Genetic Material ◽  
Nonviral Vectors ◽  
Cationic Polymers ◽  
Genetic Trait ◽  
Low Diversity ◽  
Different Types ◽  
Materials Used

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.

scholarly journals High-resolution isotope stratigraphy of the Lower Ordovician St. George Group of western Newfoundland, Canada: implications for global correlation

2009 ◽  
Vol 46 (6) ◽  
pp. 403-423 ◽  
Author(s):  
Karem Azmy ◽  
Denis Lavoie
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Sea Level Changes ◽  
Global Correlation ◽  
Lower Ordovician ◽  
Isotope Stratigraphy ◽  
Platform Carbonates ◽  
The Baltic ◽  
Marine Platform ◽  
Bottom To Top

The Lower Ordovician St. George Group of western Newfoundland consists mainly of shallow-marine-platform carbonates (∼500 m thick). It is formed, from bottom to top, of the Watts Bight, Boat Harbour, Catoche, and Aguathuna formations. The top boundary of the group is marked by the regional St. George Unconformity. Outcrops and a few cores from western Newfoundland were sampled at high resolution and the extracted micritic materials were investigated for their petrographic and geochemical criteria to evaluate their degree of preservation. The δ13C and δ18O values of well-preserved micrite microsamples range from –4.2‰ to 0‰ (VPDB) and from –11.3‰ to –2.9‰ (VPDB), respectively. The δ13Ccarb profile of the St. George Group carbonates reveals several negative shifts, which vary between ∼2‰ and 3‰ and are generally associated with unconformities–disconformities or thin shale interbeds, thus reflecting the effect of or link with significant sea-level changes. The St. George Unconformity is associated with a negative δ13Ccarb shift (∼2‰) on the profile and correlated with major lowstand (around the end of Arenig) on the local sea-level reconstruction and also on those from the Baltic region and central Australia, thus suggesting that the St. George Group Unconformity might have likely had an eustatic component that contributed to the development–enhancement of the paleomargin. Other similar δ13Ccarb shifts have been recorded on the St. George profile, but it is hard to evaluate their global extension due to the low resolution of the documented global Lower Ordovician (Tremadoc – middle Arenig) δ13Ccarb profile.

Hirnantia Fauna from the Condroz Inlier, Belgium: another case of a relict Ordovician shelly fauna in the Silurian?

2021 ◽  
pp. 1-27
Author(s):  
Sofia Pereira ◽  
Jorge Colmenar ◽  
Jan Mortier ◽  
Jan Vanmeirhaeghe ◽  
Jacques Verniers ◽  
...  
Keyword(s):  
Sea Level ◽  
Mass Extinction ◽  
Late Ordovician ◽  
Lake District ◽  
Low Diversity ◽  
Hirnantia Fauna ◽  
And Sea Level

Abstract The end-Ordovician mass extinction, linked to a major glaciation, led to deep changes in Hirnantian–Rhuddanian biotas. The Hirnantia Fauna, the first of two Hirnantian survival brachiopod-dominated communities, characterizes the lower–mid Hirnantian deposits globally, and its distribution is essential to understand how the extinction took place. In this paper, we describe, illustrate, and discuss the first macrofossiliferous Hirnantia Fauna assemblage from Belgium, occurring in the Tihange Member of the Fosses Formation at Tihange (Huy), within the Central Condroz Inlier. Six fossiliferous beds have yielded a low-diversity, brachiopod-dominated association. In addition to the brachiopods (Eostropheodonta hirnantensis, Plectothyrella crassicosta, Hirnantia sp., and Trucizetina? sp.), one trilobite (Mucronaspis sp.), four pelmatozoans (Xenocrinus sp., Cyclocharax [col.] paucicrenulatus, Conspectocrinus [col.] celticus, and Pentagonocyclicus [col.] sp.), three graptolites (Cystograptus ancestralis, Normalograptus normalis, and ?Metabolograptus sp.), together with indeterminate machaeridians and bryozoans were identified. The graptolite assemblage, from the Akidograptus ascensus-Parakidograptus acuminatus Biozone, indicates an early Rhuddanian (Silurian) age, and thus, an unexpectedly late occurrence of a typical Hirnantia Fauna. This Belgian association may represent an additional example of relict Hirnantia Fauna in the Silurian, sharing characteristics with the only other known from Rhuddanian rocks at Yewdale Beck (Lake District, England), although reworking has not been completely ruled out. The survival of these Hirnantian taxa into the Silurian might be linked to delayed post-glacial effects of rising temperature and sea-level, which may have favored the establishment of refugia in these two particular regions that were paleogeographically close during the Late Ordovician–early Silurian.

scholarly journals Benthic cyanobacteria of the genus Nodularia are non-toxic, without gas vacuoles, able to glide and genetically more diverse than planktonic Nodularia

2005 ◽  
Vol 55 (2) ◽  
pp. 555-568 ◽  
Author(s):  
Christina Lyra ◽  
Maria Laamanen ◽  
Jaana M. Lehtimäki ◽  
Anu Surakka ◽  
Kaarina Sivonen
Keyword(s):  
Baltic Sea ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Benthic Species ◽  
The Baltic Sea ◽  
Ecological Features ◽  
Gas Vacuoles ◽  
Different Types ◽  
The Baltic

Diversity and ecological features of cyanobacteria of the genus Nodularia from benthic, periphytic and soil habitats are less well known than those of Nodularia from planktonic habitats. Novel benthic Nodularia strains were isolated from the Baltic Sea and their morphology, the presence of gas vacuoles, nodularin production, gliding, 16S rRNA gene sequences, rpoB, rbcLX and ndaF genes, and gvpA-IGS regions were examined, as well as short tandemly repeated repetitive sequence fingerprints. Strains were identified as Nodularia spumigena, Nodularia sphaerocarpa or Nodularia harveyana on the basis of the size and shape of the different types of cells and the presence or absence of gas vacuoles. The planktonic strains of N. spumigena mostly had gas vacuoles and produced nodularin, whereas the benthic strains of N. sphaerocarpa and N. harveyana lacked gas vacuoles and did not produce nodularin (except for strain PCC 7804). The benthic strains were also able to glide on surfaces. In the genetic analyses, the planktonic N. spumigena and benthic N. sphaerocarpa formed monophyletic clusters, but the clusters were very closely related. Benthic strains determined as N. harveyana formed the most diverse and distant group of strains. In addition to phylogenetic analyses, the lack of the gvpA-IGS region and ndaF in N. sphaerocarpa and N. harveyana distinguished these species from the planktonic N. spumigena. Therefore, ndaF can be considered as a potential diagnostic tool for detecting and quantifying Baltic Sea bloom-forming, nodularin-producing N. spumigena strains. The data confirm that only one morphologically and genetically distinct planktonic species of Nodularia, N. spumigena, and at least two benthic species, N. sphaerocarpa and N. harveyana, exist in the Baltic Sea.

A high-resolution, multiproxy stratigraphic analysis of the Devonian–Carboniferous boundary sections in the Moravian Karst (Czech Republic) and a correlation with the Carnic Alps (Austria)

2013 ◽  
Vol 151 (2) ◽  
pp. 201-215 ◽  
Author(s):  
TOMÁŠ KUMPAN ◽  
ONDŘEJ BÁBEK ◽  
JIŘÍ KALVODA ◽  
JIŘÍ FRÝDA ◽  
TOMÁŠ MATYS GRYGAR
Keyword(s):  
Czech Republic ◽  
Gamma Ray ◽  
Sensu Stricto ◽  
Black Shales ◽  
Element Geochemistry ◽  
Carnic Alps ◽  
Sea Level Fluctuations ◽  
Stratigraphic Analysis ◽  
Carbon Isotope Excursion ◽  
Moravian Karst

AbstractA multidisciplinary correlation of the Devonian–Carboniferous (D–C) boundary sections from the Moravian Karst (Czech Republic) and the Carnic Alps (Austria), based on conodont and foraminifer biostratigraphy, microfacies analysis, field gamma-ray spectroscopy (GRS), carbon isotopes and element geochemistry, is presented in this paper. The study is focused on the interval from the MiddlePalmatolepis gracilis expansaZone (Late Famennian) to theSiphonodella sandbergiZone (Early Tournaisian). In Lesní lom (Moravian Karst), a positive δ13C excursion in theBisphatodus costatus–Protognathodus kockeliInterregnum from a distinct laminated carbonate horizon is correlated with a carbon isotope excursion from the Grüne Schneid section of the Carnic Alps and is interpreted as the equivalent of the Hangenberg black shales and a local expression of the global Hangenberg Eventsensu stricto. Higher up at both sections, a significant increase in the terrigenous input, which is inferred from the GRS signal and elevated concentrations of terrigenous elements (Si, Ti, Zr, Rb, Al, etc.), provides another correlation tieline and is interpreted as the equivalent of the Hangenberg sandstone. Both horizons are discussed in terms of relative sea-level fluctuations and palaeoceanographic changes. Recent studies show that conodont biostratigraphy is facing serious problems associated with the taxonomy of the first siphonodellids, their dependence on facies and discontinuous occurrences of protognathodids at the D–C boundary. Therefore, the correlative potential of geochemical and petrophysical signatures is high and offers an alternative for the refining of the problematic biostratigraphic division of the D–C boundary.

scholarly journals Fish larvae in Bahía Sebastián Vizcaíno and the adjacent oceanic region, Baja California, México

Check List ◽  
2007 ◽  
Vol 3 (3) ◽  
pp. 204 ◽  
Author(s):  
S. Patricia A. Jiménez-Rosenberg ◽  
Ricardo J. Saldierna-Martínez ◽  
Gerardo Aceves-Medina ◽  
Víctor M. Cota–Gómez
Keyword(s):  
Interannual Variability ◽  
Seasonal Variability ◽  
Baja California ◽  
El Nino ◽  
Fish Larvae ◽  
Taxonomic Composition ◽  
Oceanic Region ◽  
Low Diversity ◽  
Engraulis Mordax ◽  
High Diversity

The taxonomic composition of the fish larvae assemblage of Bahía Sebastián Vizcaíno and the adjacent oceanic region is presented based on oblique zooplankton hauls made during 12 oceanographic surveys between fall 1997 and fall 2000. In total, 186 taxa representing 71 families were collected. Myctophidae, Phosichthyidae, and Engraulidae were the most abundant during winter and Myctophidae, Merlucciidae, and Bathylagidae during spring. In summer and fall Phosichthyidae and Myctophidae were the most abundant. During 1999 and 2000, seasonal variability was identified in the area by the fish larvae composition, defining winter and fall as a low diversity period and spring and summer as a high diversity period. Interannual variability was detected with an El Niño event, with higher larval abundances of tropical and subtropical taxa, and a La Niña event, with high abundances of larvae of Engraulis mordax. 

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