scholarly journals Foraminiferal assemblage in the coral-bearing limestones of the Vršatec area (Pieniny Klippen Belt, Western Carpathians, Slovakia)

2013 ◽  
Vol 64 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Elżbieta Morycowa ◽  
Barbara Olszewska
Keyword(s):  
Benthic Foraminifera ◽  
Scleractinian Coral ◽  
Late Jurassic ◽  
Coral Community ◽  
Scleractinian Corals ◽  
Western Carpathians ◽  
Foraminiferal Assemblage ◽  
Pieniny Klippen Belt

Abstract The paper deals with benthic foraminifera occurring with the scleractinian corals in the Jurassic biohermal and peribiohermal coral-bearing limestones of the Vršatec area (Czorsztyn Succession, Slovak Pieniny Klippen Belt). The coral community is dominated by branching forms of the genus Thecosmilia. Co-occurring abundant benthic foraminifera belong to the species Rumanolina seiboldi, R. elevata, Paalzowella turbinella and Troglotella incrustans. The coral-bearing limestones were initially assigned to the Oxfordian on the basis of the microfacies analyses and bivalve and scleractinian faunas. In recent papers they are assigned to the Bajocian on the basis of ammonites found in the neptunic dykes and stratigraphic superimposition criteria. However, the stratigraphic distribution of the majority of the identified foraminifera indicates that like most scleractinian coral taxa they are not known earlier than in the Late Jurassic. The Late Jurassic age of these coral-bearing limestones is also suggested by an encrusting microproblematic organism Iberopora bodeuri.

scholarly journals Coverage Increases of Porites astreoides in Grenada Determined by Shifts in Size-Frequency Distribution

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 288
Author(s):  
Ryan G. Eagleson ◽  
John S. Lumsden ◽  
Lorenzo Álvarez-Filip ◽  
Christophe M. Herbinger ◽  
Ryan A. Horricks
Keyword(s):  
Coral Community ◽  
Scleractinian Corals ◽  
Area Measurement ◽  
Coralline Algae ◽  
Measurement Tool ◽  
Size Frequency Distribution ◽  
Point Count ◽  
Porites Astreoides ◽  
The Mean ◽  
The Caribbean

Despite coral community collapse, the mustard hill coral (Porites astreoides) is a species currently experiencing success throughout the Caribbean. The inshore reefs of Grenada were selected to study the influence of benthic factors on the abundance, size, and coverage of P. astreoides colonies. Surveys of reef communities along established 30 m transects were conducted at eight sites in 2014 and 2017 using a 0.5 m² quadrat. Coral Point Count was used to annotate the images, estimating the coverage of scleractinian corals, sponges, algae, and benthic substrates. Coverage, size, and abundance of P. astreoides colonies were quantified using the area measurement tool in ImageJ standardized against the quadrats. There were significant differences in benthic community assemblages between islands, selected sites, and between years. From 2014 to 2017 there was a significant decrease in the mean abundance of P. astreoides colonies and significant increases in mean colony size and coverage. The presence of P. astreoides colonies was significantly correlated with: rubble (−), sand (−); pavement (+); macroalgae (−); coralline algae (+); sponges (varying response); gorgonians (−); massive corals (+); and branching corals (−). P. astreoides follows similar recruitment patterns as other scleractinian corals. Observed changes in P. astreoides populations appear to indicate a recovery event following a disturbance, potentially tropical storm Chantal in 2013.

Early Silurian Benthic Foraminifera from Saudi Arabia - including the oldest known multichambered lituolids

Stratigraphy ◽  
2020 ◽  
pp. 141-185
Author(s):  
Michael A. Kaminski ◽  
Pramudya R. D. Perdana
Keyword(s):  
Saudi Arabia ◽  
New Species ◽  
North America ◽  
Benthic Foraminifera ◽  
Early Evolution ◽  
Foraminiferal Assemblage ◽  
New Findings ◽  
New Finding ◽  
Agglutinated Foraminifera

ABSTRACT: A diverse assemblage of early Silurian agglutinated foraminifera is described from the transitional facies between the Qusaiba and Sharawra Formations of theQalibah Group of Saudi Arabia. The agglutinated foraminiferal assemblage consists of 73 species belonging to 24 genera, and is found in in dark graptolite-bearing claystone of Aeronian age. The assemblage is highly diverse compared with coeval early Silurian assemblages reported from Europe and North America. The assemblage is comprised mainly of species belonging to the monothalamid genera Saccammina, Psammosphaera, Lagenammina, Thurammina, Thuramminoides, Amphitremoida, Bathysiphon, Rhabdammina, and the tubothalamid genera Hyperammina, Tolypammina and Turritellella. The new species Thuramminoides ellipsoidalis n. sp. is described herein, but many of the species left in open nomenclature are also likely to be new. The assemblage also includes rare specimens belonging to the globothalamid (lituolid) genera Ammobaculites and Simobaculites. This new finding revises our understanding of the early evolution of the multichambered globothalamid foraminifera. Although the simple multichambered with rectilinear chamber arrangement are known from the Ordovician, our new findings show that the coiled globothalamids belonging to the order Lituolida are older than previously thought, and were already present in Gondwana by about 440 Ma.

scholarly journals A modern scleractinian coral with a two-component calcite–aragonite skeleton

2020 ◽  
pp. 202013316
Author(s):  
Jarosław Stolarski ◽  
Ismael Coronado ◽  
Jack G. Murphy ◽  
Marcelo V. Kitahara ◽  
Katarzyna Janiszewska ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Southern Ocean ◽  
Phylogenetic Relationship ◽  
Fossil Record ◽  
Scleractinian Coral ◽  
Scleractinian Corals ◽  
Marine Organisms ◽  
Close Phylogenetic Relationship ◽  
Two Component ◽  
Selection Of

One of the most conserved traits in the evolution of biomineralizing organisms is the taxon-specific selection of skeletal minerals. All modern scleractinian corals are thought to produce skeletons exclusively of the calcium-carbonate polymorph aragonite. Despite strong fluctuations in ocean chemistry (notably the Mg/Ca ratio), this feature is believed to be conserved throughout the coral fossil record, spanning more than 240 million years. Only one example, the Cretaceous scleractinian coral Coelosmilia (ca. 70 to 65 Ma), is thought to have produced a calcitic skeleton. Here, we report that the modern asymbiotic scleractinian coral Paraconotrochus antarcticus living in the Southern Ocean forms a two-component carbonate skeleton, with an inner structure made of high-Mg calcite and an outer structure composed of aragonite. P. antarcticus and Cretaceous Coelosmilia skeletons share a unique microstructure indicating a close phylogenetic relationship, consistent with the early divergence of P. antarcticus within the Vacatina (i.e., Robusta) clade, estimated to have occurred in the Mesozoic (ca. 116 Mya). Scleractinian corals thus join the group of marine organisms capable of forming bimineralic structures, which requires a highly controlled biomineralization mechanism; this capability dates back at least 100 My. Due to its relatively prolonged isolation, the Southern Ocean stands out as a repository for extant marine organisms with ancient traits.

scholarly journals Transects, quadrats, or points? What is the best combination to get a precise estimation of a coral community?

2019 ◽  
Author(s):  
Luis M. Montilla ◽  
Emy Miyazawa ◽  
Alfredo Ascanio ◽  
María López-Hernández ◽  
Gloria Mariño-Briceño ◽  
...  
Keyword(s):  
Community Structure ◽  
Coral Reef ◽  
Effect Size ◽  
Standard Error ◽  
Scleractinian Coral ◽  
Statistical Power ◽  
Coral Community ◽  
Sampling Effort ◽  
Precise Estimation

ABSTRACTThe characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power, however, always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points. For this, the MultSE of 36 sites previously sampled was estimated, using four 30m-transects with 15 photo-quadrats each and 25 random points per quadrat. We obtained that the MultSE was highly variable between sites and is not correlated with the univariate standard error nor with the richness of species. Then, a subset of sites was re-annotated using 100 uniformly distributed points, which allowed the simulation of different numbers of transects per site, quadrats per transect and points per quadrat using resampling techniques. The magnitude of the MultSE stabilized by adding more transects, however, adding more quadrats or points does not improve the estimate. For this case study, the error was reduced by half when using 10 transects, 10 quadrats per transect and 25 points per quadrat. We recommend the use of MultSE in reef monitoring programs, in particular when conducting pilot surveys to optimize the estimation of the community structure.

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