scholarly journals Morphological variability of the nanoplanktonic diatom Thalassiosira laevis from coastal waters of Province of Buenos Aires (Argentina).

2017 ◽  
Vol 52 (4) ◽  
pp. 617-622
Author(s):  
Eugenia A. Sar ◽  
Inés Sunesen

Morphological variability of the nanoplanktonic diatom Thalassiosira laevis from coastal waters of Province of Buenos Aires (Argentina). Despite the fact that the genus Thalassiosira was previous and extensively studied including ultrastructural analysis of species found in phytoplanktonic samples collected from marine waters of Argentina, nanoplanktonic species have been frequently overlooked. This paper is devoted to show the morphological variation of Thalassiosira laevis, a nanoplanktonic species collected from marine coastal waters of the Province of Buenos Aires, to compare Argentinean material with those from China, Korea and Brazil described in the literature, and to record it for the first time from Argentina.

2018 ◽  
Vol 53 (2) ◽  
pp. 195-200
Author(s):  
Andrea S. Lavigne ◽  
Inés Sunesen ◽  
Eugenia A. Sar

Several ultrastructural analyses of taxa belonging to the genus Thalassiosira from Argentinean coastal waters were carried out, nevertheless, the smaller fraction of the nanoplanktonic Thalassiosira was frequently overlooked. The aim of this study is to show the morphological variation of T. catharinensis, to compare material found in marine coastal waters of Anegada Bay, Province of Buenos Aires, with the material analyzed in the protologue and allied taxa, and to record the species for the first time in Argentina, extending its distribution.


Author(s):  
Svetlana Rubtsova ◽  
Svetlana Rubtsova ◽  
Natalya Lyamina ◽  
Natalya Lyamina ◽  
Aleksey Lyamin ◽  
...  

The concept of a new approach to environmental assessment is offered in the system of integrated management of the resource and environmental safety of the coastal area of the Black Sea. The studies of the season and daily changeability in the bioluminescence field in the Sevastopol coastal waters has been conducted. For the first time considerable differences in the bioluminescence field seasonal changes in the surface and deep water layers and the reasons conditioning this phenomenon have been shown, using a method of multidimensional statistical analysis. The bioluminescence field vertical profile change in the Black sea coastal waters in the autumn period at night has been studied. It has been shown that according to the character of bioluminescence parameters dynamics a water column can be divided into layers: upper (0 – 35 m) and deep water (36 – 60 m). It has been revealed that life rhythms of the plankton community are the main reason for the bioluminescence field intensity variability. It has been revealed that 14-hour periodicity of the bioluminescence field is related to the changes in light and its variations with 2,5…4,5 hours are conditioned by planktonts endogenous daily rhythms. And here biotic factors effect mostly periodicity of the bioluminescence field intensity increase and fall down at the dark time of the day. Abiotic factors are of less importance in circadian rhythmic of the bioluminescence field in the neritic zone.


Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1769
Author(s):  
Maria Macarena Arrien ◽  
Maite M. Aldaya ◽  
Corina Iris Rodriguez

Agriculture is the largest fresh water consuming sector, and maize is the most produced and consumed crop worldwide. The water footprint (WF) methodology quantifies and evaluates the water volumes consumed and polluted by a given crop, as well as its impacts. In this work, we quantified for the first time the green WF (soil water from precipitation that is evapotranspired) and the green virtual water exports of maize from Buenos Aires province, Argentina, during 2016–2017, due to the relevance of this region in the world maize trade. Furthermore, at local level, we quantified the green, blue (evapotranspired irrigation), and grey (volume of water needed to assimilate a pollution load) WF of maize in a pilot basin. The green WF of maize in the province of Buenos Aires ranged between 170 and 730 m3/ton, with the highest values in the south following a pattern of yields. The contribution of this province in terms of green virtual water to the international maize trade reached 2213 hm3/year, allowing some water-scarce nations to ensure water and water-dependent food security and avoid further environmental impacts related to water. At the Napaleofú basin scale, the total WF of rainfed maize was 358 m3/ton (89% green and 11% grey) and 388 m3/ton (58% green, 25% blue, and 17% grey) for the irrigated crop, showing that there is not only a green WF behind the exported maize, but also a Nitrogen-related grey WF.


2017 ◽  
Vol 57 (37) ◽  
pp. 473
Author(s):  
José Matias Rusconi ◽  
Maria Fernanda Achinelly ◽  
Nora Beatriz Camino

Thelastomatidae is one of the largest families parasitizing insects, within the order Oxyurida. In this work we reported parasitism in nymphs and adults of Neocurtilla claraziana by two different thelastomatid species as a part of a field survey on agricultural pests. Nymphs and adults of this insect were isolated from grasslands of Buenos Aires State, Argentina using a tensio-active solution. The nematode species Gryllophila skrjabini Sergiev, 1923 and Cephalobellus magalhaesi Schwenk, 1926 are briefly described and measurements are given. Both nematodes are reported for the first time in Argentina with C. magalhaesi being the second isolation of this species in the world. Neocurtilla clarziana is a new host record for G. skrjabini.


Author(s):  
I.V. Mosharova ◽  
V.V. Il’inskij ◽  
O.V. Il’ina

Sanitary and microbiological researches of a coastal surface water of the southern part of Lake Baikal (from the Listvyanka to the Tanghui) were conducted in June, 2017. Total number of bacteria varied over a wide range – from 0.93 million сells/ml up to 2:05 million сells/ml, with an average 1.41 ± 0.3 million сells/ml. Biomass of bacteria varied from 11.05 to 305.00 mg С/m3, with an average of 123.34 mg С/m3. Coastal waters of the southern site of Lake Baikal mainly had a beta-meso-saprobic status in June, 2017. The total microbial number was determined with the use of the test systems for the first time. The values of the total microbial number were less than 1 000 COU/ml and varied from 9 to 412 COU/ml. Innovative test systems Petrifilm are of great interest for rapid assessments of the sanitary and microbiological status of reservoirs directly in the field conditions.


2009 ◽  
Vol 69 (4) ◽  
pp. 1059-1071 ◽  
Author(s):  
M. Garcia ◽  
C. Odebrecht

The detailed description of rarely recorded Thalassiosira species in Brazil is presented with light microscope (LM) and scanning electron microscope (SEM) illustrations. A total of 78 phytoplankton net samples (20 µm) collected between the years 2000 and 2006 in coastal waters of southern Brazilian, Cassino Beach and the estuary of Lagoa dos Patos, were studied in cleaned material using the Axiovert Zeiss LM and Jeol 6060 SEM. Water temperature and salinity of samples and six species are presented: Thalassiosira endoseriata, T. hendeyi, T. lundiana, T. minuscula, T. oceanica and T. wongii. Two species, Thalassiosira hendeyi and T. endoseriata were the most common being observed in all seasons at Cassino Beach in a wide temperature range (10-26 ºC), while only sporadically in the estuary of Lagoa dos Patos. Thalassiosira endoseriata, T. lundiana, T. oceanica and T. wongii are for the first time reported in Brazilian coastal waters. The latter two species, rarely recorded in the world, are fully illustrated based on Brazilian material.


Nova Hedwigia ◽  
2001 ◽  
Vol 73 (1-2) ◽  
pp. 199-228
Author(s):  
Eugenia A. Sar ◽  
Inés Sunesen ◽  
Cecilia Castaños

2020 ◽  
Vol 131 (3) ◽  
pp. 505-520
Author(s):  
Janet Nolasco-Soto ◽  
Mario E Favila ◽  
Alejandro Espinosa De Los Monteros ◽  
Jorge González-Astorga ◽  
Gonzalo Halffter ◽  
...  

Abstract We analysed the genetic divergence and morphology of the aedeagus (i.e. phallobase and parameres) in Canthon cyanellus at different geographical levels. The results from both approaches were compared with the current taxonomic assignment of the C. cyanellus complex, which includes three subspecies. We found a high variation in all the morphological characters of the aedeagus in the populations analysed; the morphometric variation was not geographically structured, either by population or by region. The genealogical analysis indicates a significant genetic structure that does not match either the morphological variation in the male genitalia or the previous subspecific taxonomic classification. Our results suggest that the morphological variation of the aedeagus is seemingly not an isolating reproductive barrier and that the intra- and interpopulation morphological variability of the aedeagus in the C. cyanellus complex does not permit the division into several species. We suggest that other evolutionary forces, such as genetic drift and sexual selection, have influenced the evolution of the male genitalia and the incipient differentiation of this species complex.


Zootaxa ◽  
2008 ◽  
Vol 1743 (1) ◽  
pp. 53 ◽  
Author(s):  
ANA LÚCIA DA COSTA PRUDENTE ◽  
MÁRCIO ANDRÉ AMORIM DA SILVA ◽  
WÁLDIMA ALVES DA ROCHA ◽  
FRANCISCO LUÍS FRANCO

The genus Xenoxybelis contains two species, X. argenteus and X. boulengeri, characterized by semi-arboreal habits and an extremely thin rostral area, classified in the subfamily Xenodontinae (Colubridae). Xenoxybelis boulengeri is considered a rare species and is poorly represented in scientific collections. Its external morphology is known only from the original description and seven other specimens. In this study, twenty additional specimens were examined from the Brazilian states of Acre, Amazonas and Rondônia. Variation in meristic and morphometric characters are described, and new characters are incorporated in a revised diagnosis of the species. Illustrations and a description of the hemipenes of X. boulengeri are presented for the first time. Analysis of morphological and molecular characters permit allocation of Xenoxybelis to the tribe Phylodryadini, together with Ditaxodon, Philodryas, Pseudablabes and Tropidodryas.


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