natural substratum
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2020 ◽  
Vol 8 (4) ◽  
pp. 478
Author(s):  
Isabel Iturrieta-González ◽  
Dania García ◽  
Josep Guarro ◽  
Josepa Gené

In a survey of microfungi from plant debris collected in Vietnam, two new hyphomycetous species were found, which belong to the genera Heliocephala and Pseudopenidiella and the family Microthyriaceae (Microthyriales, Dothideomycetes). Maximum Likelihood and Bayesian Inference sequence analyses of the internal transcribed spacers (ITS) and large subunit (LSU) of the ribosomal DNA barcodes allowed assessing the phylogenetic relationships of the new species with other species of the respective genera. Heliocephala variabilis sp. nov. was closely related to Heliocephala elegans, Heliocephala gracilis, and Heliocephala zimbabweensis, from which it was morphologically distinguished by its smaller conidiophores and non-rostrate conidia of up to four septa on the natural substratum. Pseudopenidiella vietnamensis sp. nov. was related to Pseudopenidiella piceae and Pseudopenidiella podocarpi and differed from the former principally by its lack of microcondiophores and from P. podocarpi by having larger macroconidiophores and smooth conidia. Key morphological features to distinguish the accepted species in Heliocephala and Pseudopenidiella are also provided. In addition, Pseudopenidiella pini was excluded from the genus on the basis of its morphological features.


2013 ◽  
Vol 463-464 ◽  
pp. 1049-1059 ◽  
Author(s):  
M. Regadío ◽  
I.S. de Soto ◽  
M. Rodríguez-Rastrero ◽  
A.I. Ruiz ◽  
M.J. Gismera ◽  
...  
Keyword(s):  

1998 ◽  
Vol 49 (6) ◽  
pp. 541 ◽  
Author(s):  
Louise M. Emmerson ◽  
Gregory J. Collings

The effect of the surrounding community and spatial extent of disturbance on recruitment was investigated in a mixed stand (dominated by large brown algae of the order Fucales) on a subtidal rocky platform in South Australia. In particular, survival and growth of Cystophora and Sargassum recruits on natural substratum were examined in artificially cleared areas of three sizes (30 × 30 cm, 60 × 60 cm and 100 × 100 cm). Abundance and growth of recruits was monitored for 6 months at both the edge and the centre of the clearances. The influence of clearance size and position within a clearance on the abundance of recruits changes with time. Initially, the size of clearance was most important, with larger clearances supporting denser stands of recruits. However, after 143 days, position within the clearance became important, with greater mortality at the edges than at the centre. The large residual values associated with the analysis were evidence of the variability of the interactions within this community. The results demonstrate the importance of the consideration of spatial and temporal scales, and particularly the position within a disturbed area, in recruitment studies.


1998 ◽  
Vol 49 (5) ◽  
pp. 429 ◽  
Author(s):  
T. M. Glasby

A nested hierarchical sampling design was used to estimate the scales of natural variability in developing assemblages of subtidal epibiota on rocky reefs. The appropriate spatial scales were needed for sampling to test for environmental impact in this habitat. Sandstone settlement plates were used to mimic the natural substratum. They were designed and deployed in such a way that the effects of any supporting structures were minimized. Differences in recruitment of epibiota were found at all of the spatial scales examined (10s, 100s and 1000s of metres). When differences were found at the smallest spatial scale, they were generally still detected at the two larger scales. The results highlighted the need for adequate small- and large-scale spatial replication for studies of environmental impact.


1992 ◽  
Vol 21 ◽  
Author(s):  
Júlio Dellome Filho

É estudado o substrato natural dos estágios larvais de similídeos no Rio Marumbi (Morretes, Paraná, Brasil). É formado por plantas marginais e submersas. Fios plásticos amarelos e verdes foram usados como substratos artificiais e foi mostrado que os fios amarelos são os preferidos pelas larvas. A fauna associada aos imaturos é constituída de artrápodos e peixes. Larvas de Athericidae foram encontrada em matéria em decomposição. Abstract The natural substratum of the black flies larval stages on Marurnbi River (Morreres, Paraná, Brasil) were exaniined. lt was found to be constituted by marginal and submerged plants only. Yellow and green plastic threads as artificial substratum were used and showed that immatures prefer the yellow ones. The associated fauna to immatures was found to be constituted by arthropods and fishes. Athericidae larvae were found in decomposed organic material; this is the first citation of this farnily in Brazil. Résumé Le substrat naturel des larves de quelques Simuliidae dans le fleuve Marumbi (Morretes, Paraná, Brésil) est examiné. Les plantes marginales et submergeés sont l'unique substrat. Entre fils de plastique verds et jaunes, les fils jeunes sont de préférence de les larves comme substrat artificiel. La faune associeé sont l’espéces des poisons et des artropodes.


1979 ◽  
Vol 49 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Steven Weinberg

Branches of gorgonians belonging to four different Mediterranean species (Eunicella singularis (Esper), Paramuricea clavata (Risso), Corallium rubrum (Linnaeus) and Lophogorgia ceratophyta (Linnaeus)) were transplanted to different habitats by means of three different methods, and survival and growth rates were observed over periods ranging from three months to over two years. It was concluded that transplantation of animals still fixed on their natural substratum is to be preferred over transplantations involving artificial devices. Transplanted adult branches of all four species tolerate conditions under which the species are not usually encountered. Tolerances or preferences of larval and juvenile phases must account for these discrepancies. Transplants never survived in shallow waters. Algal competition, abrasion and mechanical destruction due to turbulent water conditions, and in some cases high irradiance values are among the lethal factors. In deeper water, sedimentation is also fatal, although in nature some colonies survive under similar conditions.


1965 ◽  
Vol 5 (2) ◽  
pp. 273-284 ◽  
Author(s):  
S. J. Prokhovnik

AbstractOur present view of the universe suggest that the set of mutually receding galaxies may provide a natural substratum for the propagation of light. It is shown that this assumption leads to a consistent derivation and interpretation of special relativity, along the lines evvisaged by Lorentz but requiring also the employment of Einstein's measurement definitions. The time-dilatation and Fitzgerald contraction effects emerge as intelligible consequences of this approach, and their interaction with an associated anisotropy effect produces the relativity of simultaneity, the reciprocity phenomenon and the results described by Einstein's principles; the approach provides a definitive resolution of the “clock paradox” within the framework of Special Relativity.


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