scholarly journals Morphological variation of two marine diatom species, Nitzschia ventricosa and Ardissonea crystallina (Bacillariophyta)

2016 ◽  
Vol 1 (4) ◽  
pp. 53-62
Author(s):  
K. I. Shorenko ◽  
Yu. A. Podunai ◽  
O. I. Davidovich ◽  
M. S. Kulikovskyi

The relevance of the article is caused by insufficient knowledge of the problem of understanding of the diatoms species scope, particularly in vitro. The aim of the research is to study the morphological variability in cultures of two species of marine pennate diatoms, Nitzschia ventricosa and Ardissonea crystallina using methods of light and scanning electron microscopy.  In addition we assessed the impact of salinity on morphological parameters of A. crystallina valves in the experiment, which is used in the diagnosis of the type. The material for investigation were isolates (algological pure cultures and clones) obtained in vitro. N. ventricosa isolates were received from natural populations collected at coasts of Canary Islands, Islands of Martinique and Texas (Gulf of Mexico). The clones of A. crystallina were allocated from benthic samples in Kazachya Bay (Sevastopol, the Black Sea). The culture was established with the micropipette way and grown in Petri dishes on ESAW media with natural light at a temperature of 20 °C. We refer to a clone (strain) as vegetative offspring derived from a single cell, while the algological pure culture is a group of clones of the same species. The algological pure culture of A. crystallina (consisting of several strains) was physically separated and grown in parallel with six levels of salinity (8, 12, 17, 30, 38 and 48 ‰) for two months. To obtain the required initial salinity the medium salinity (36 ‰) was diluted with the necessary amount of distilled water, or NaCl was added. The terms of keeping of cultures in artificial conditions until the preparation of drugs were no more than 2 months longer, in order to avoid teratological changes. The species Nitzschia ventricosa was originally discovered on the coast of Hong Kong and described in 1873 by the British naturalist F. Kitton. In the Black and Azov seas' benthos and plankton the species N. ventricosa was not observed. While studying the collected materials of the British Natural History Museum (London), the holotype of N. ventricosa was not marked by F. Kitton. The slide № 10365 from the collections of the British Museum (Collection Deby), with this type of material from Hong Kong, was studied. The material in the slide was decided to be authentic (specimina authentica). The material showed the proximity of morphometric characteristics of the valves. Data was compared to the ones given from other Pacific populations. The species Ardissonea crystallina (C. Agardh) Grunow was described by Swedish botanist C. Agardh in 1824 as Diatoma crystallinum C. Agardh. The type locality (locus typicus) are the waters of Sinus Codani, which corresponds to Kattegat Strait, located between the East coast of the Jutland peninsula and the south-western part of the Scandinavian Peninsula. Both species are widely distributed in the oceans and are found regularly in the benthos and plankton, however, they have not been studied in cultures. The following conclusions were obtained: 1. Morphological variability in cultures of N. ventricosa and A. crystallina was comparable with those obtained on the material from natural populations. 2. We managed to get both types of auxospore in the cultures that allowed us to estimate the upper limit of the size range of both types of cells. For N. ventricosa it was 616.0 µm, for A. crystallina the maximum length was 678.0 µm. 3. The variation of number of striae and fibulae in one clone of N. ventricosa was higher than in pure cultures. 4. It has been shown that A. crystallina was able to live while salinity was from 8 to 48 ‰. 5. The A. crystallina culture derived from natural population of the Black Sea, was close to the number of striae to the population from the coast of Canada (Shalёr Bay). 6. The content of the cultures at different rates of salinity for two months has not led to significant morphological changes of A. crystallina cells. There was no effect of salinity on qualitative morphological features of A. crystallina. With an increase of salinity in the experiment arrangement density of striae and areolae of A. crystallina tend to increase, and the width of the cell — to decrease. With the increase of salinity, an increase of the breadth ranges of the striae number variation was observed.

Inventions ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 46
Author(s):  
Catalin Anton ◽  
Angela-Eliza Micu ◽  
Eugen Rusu

Traditionally and socially, the tourism in Constanta is considered to be important to the local economy. Sun and beach locations are both a draw for locals and tourists to the city, on the Black Sea. However, vacation-oriented activities in the city only have a seasonal cycle. In this paper, we proposed to analyze the mass tourist activity in Constanta, taking into account economic, social, and environmental conditions. Additionally, we attempted to build a model based on the data available. The model was developed using a PESTEL analysis to determine the supportability factor of the indicators identified. We also set out to create a projection of the activities proposed for analysis by 2050. To create a model for coastal areas, the data used in this research must be accurate and consistent. Furthermore, correctly identifying indicators and their relationships is a critical step in conducting a thorough study. Last but not least, finding the calculation coefficient for the activity in question is critical, as collecting data from various activities might be challenging when trying to find a feasible model.


Author(s):  
T. V. Efremova ◽  
Yu. N. Goryachkin ◽  
◽  

Anthropogenic impact on lithodynamics of the coastal zone changes the natural dynamics of bottom sediments, which leads to increased abrasion and swelling of beaches, activation of landslide processes creating a threat of destruction of the coastal infrastructure. The article aims at providing an overview of the scientific literature on the anthropogenic impact on lithodynamics of the coastal zone of the southern and western coasts of the Black Sea (shores of Romania, Bulgaria and Turkey). The work shows that with all the differences in the natural conditions of the coastal zones of these countries the types of anthropogenic effects they undergo are almost the same. These include: hydrotechnical construction without regard to the impact on the neighbouring coast sections; reduction of solid river flow due to river regulation by reservoirs; construction of capital facilities directly on the beaches; illegal extraction of sand from beaches and river beds; dredging with sale of the extracted material to construction companies; covering of cliffs by various structures; destruction of coastal dunes, etc. The main negative consequences of these actions are reflected in disruption of natural dynamics and shortages of bottom sediments, changes in the coastline, reduced aesthetic attractiveness and accessibility of shores, destruction of coastal ecosystems. The article also provides information on the legislation of these countries regarding environmental management in the coastal zone


2019 ◽  
Vol 38 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Thomas M. Hoyle ◽  
Manuel Sala-Pérez ◽  
Francesca Sangiorgi

Abstract. The morphology of dinoflagellate cysts (dinocysts) is related not only to the genetics of the motile dinoflagellate from which it derives, but is also dependent on a range of environmental factors including salinity, temperature and nutrient status. Although this knowledge improves our understanding of the drivers behind dinocyst morphological variations, it makes the taxonomy governing their description somewhat complex. In basins such as the Black Sea, where environmental change can be extreme and occurs on relatively short (millennial) timescales, taxonomy becomes particularly challenging. Morphological continua can be observed between described forms, displaying a large range of intermediate phenotypes that do not necessarily correspond to any genetic difference. As these morphological nuances may preserve information about palaeoenvironments, it is important to find a systematic method of characterising morphotypes. Here, we show a dinocyst matrix within which dinocysts are described according to their similarity to (or difference from) described forms based on key descriptive parameters. In the example set out here, cyst shape and degree of process and/or ectophragm development are taken as two key parameters in Pyxidinopsis psilata and Spiniferites cruciformis, and can allow the description of intermediate forms even though the definitions do not overlap. We review some frequently occurring morphotypes and propose that using matrices to show the gradual variation between endmember forms is the most pragmatic approach until cyst–theca studies and genetic sequencing can be used to demonstrate relationships between genotypes and morphotypes. As prior studies propose salinity to be a primary driver of intraspecific variability, the endmembers presented may represent salinity extremes within an overall brackish environment. Although we cannot assign each morphotype to a value or a range of an environmental parameter (e.g. salinity) as the different morphotypes can occur in the same sample, using this matrix allows preservation of information about morphological variability without creating taxonomic categories that are likely to require alteration if genetic evidence becomes available.


Phytotaxa ◽  
2021 ◽  
Vol 480 (1) ◽  
pp. 1-21
Author(s):  
SOFIA S. SADOGURSKA ◽  
JOÃO NEIVA ◽  
ANNALISA FALACE ◽  
ESTER A. SERRÃO ◽  
ÁLVARO ISRAEL

Brown algae of the genus Cystoseira sensu lato form the most diverse and productive marine ecosystems throughout the Mediterranean Sea and have equal roles also in the Black Sea where they have been decreasing in the recent years. The taxonomy of Cystoseira s.l. taxa from the Black Sea is still not well understood, and questions arise when related taxa have to be delimited. In addition to morphological descriptions, this study provides for the first time molecular data of the Black Sea Cystoseira s.l. distinct morphologies as an additional tool to clarify their identities and phylogenetic affinities. The analysis of two mitochondrial markers (cytochrome oxidase subunit 1—COI, and 23S-tRNAVal intergenic spacer—mt-spacer) showed that Cystoseira s.l. specimens from the Black Sea belong to two recently resurrected genera, namely Gongolaria and Ericaria. Molecular data confirm the morphological identification of G. barbata, which is characterized by high morphological plasticity in the Black Sea. The morphological data presented in this study support the transition of G. barbata to the genus Gongolaria, which was previously proposed based solely on genetic data. For the Black Sea endemic taxon C. bosphorica, sequence divergence suggests conspecificity with Mediterranean Sea species E. crinita and E. barbatula. However, considering original morphological characteristics of the taxon, its geographical isolation, and endemism, the new combination Ericaria crinita f. bosphorica comb. nov. is proposed.


2021 ◽  
Vol 17 (1) ◽  
pp. 141-146
Author(s):  
Valentin-Costinel TOTIR ◽  
Roxana ALEXANDRU

Abstract: During history, the main channel of communication and cooperation between countries was through commerce and, consequently, through transport. Among all the transport ways, the maritime transport is the one that offers the best cost – benefits ratio. This article is addressed to all the people involved or interested in the economic and military fields and aims to highlight the importance of the Black Sea and North Sea connecting corridor in ensuring peace and stability in Europe in general and in South-Eastern Europe in special. To achieve this goal, we will review the historical conflicts among European countries for waterway control and make a descriptive analysis of the stability situation in the areas affected by them. Furthermore, using the hypothetical-deductive method, we will highlight the manner in which the connection of the Black Sea with the North Sea has influenced economic and military exchanges between riparian states and the impact on stability across European continent. At the end of the article, we will show how economic and military stability in south-eastern Europe is influenced and threatened by geopolitical changes in the wider Black Sea region and how this stability can be maintained and strengthened due to the great possibilities for economic cooperation among the countries of Western and South-Eastern Europe. The novelty of this approach is that it aims to analyze the importance of the Black Sea-North Sea channel in the context of fundamental changes in the politico-military situation in South-East Europe, generated by the expansion of the Russian Federation and the conflict between Turkey and Greece, NATO member countries.


2003 ◽  

Monograph is prepared on the basis of the materials collected in near-shore waters of Crimea in 2003, and the retrospective data. Modern condition of biological diversity in near-shore zone of Crimea is shown on the basis of analysis of qualitative and quantitative composition of micro- and zooplankton, phyto- and zoobenthos, ichthyofauna and parasite fauna; the recommendations on conservation of biological diversity are given. Responses of biota on the appearance of new species in communities and on the impact of some anthropogenic factors are analyzed. Characteristics of the Black Sea plankton bioluminescents and the bioluminescence field forming by them in neritic zone of Crimea are shown. Lists of species of main groups of flora and fauna from the different regions of near-shore waters of Crimea are made.


Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 443-452 ◽  
Author(s):  
Arseny A. Kubryakov ◽  
Sergey V. Stanichny ◽  
Denis L. Volkov

Abstract. Satellite altimetry measurements show that the magnitude of the Black Sea sea level trends is spatially uneven. While the basin-mean sea level rise from 1993 to 2014 was about 3.15 mm yr−1, the local rates of sea level rise varied from 1.5–2.5 mm yr−1 in the central part to 3.5–3.8 mm yr−1 at the basin periphery and over the northwestern shelf and to 5 mm yr−1 in the southeastern part of the sea. We show that the observed spatial differences in the dynamic sea level (anomaly relative to the basin-mean) are caused by changes in the large- and mesoscale dynamics of the Black Sea. First, a long-term intensification of the cyclonic wind curl over the Black Sea, observed in 1993–2014, strengthened divergence in the center of the basin and led to the rise of the sea level in coastal and shelf areas and a lowering in the basin's interior. Second, an extension of the Batumi anticyclone to the west resulted in  ∼  1.2 mm yr−1 higher rates of sea level rise in the southeastern part of the sea. Further, we demonstrate that the large-scale dynamic sea level variability in the Black Sea can be successfully reconstructed using the wind curl obtained from an atmospheric reanalysis. This allows for the correction of historical tide gauge records for dynamic effects in order to derive more accurate estimates of the basin-mean sea level change in the past, prior to the satellite altimetry era.


2002 ◽  
Vol 46 (8) ◽  
pp. 187-194 ◽  
Author(s):  
Č Maksimović ◽  
C.K. Makropoulos

In order to effectively manage the wide variety of physical, chemical biological and ecological processes in a sensitive coastal environment such as the Black Sea, current environmental management objectives are no longer sufficient: a new management approach has to address the intimate functional linkage between the river basin and the costal environment. Current water quality legislation requires compliance to emission levels based on the chemical analysis of water samples taken at discharge points, such as treatment plants discharging into rivers. While such measures provide a relative indication of the water quality at the point of discharge, they fail to describe accurately and sufficiently the quality of the water received from the watershed or basin. As water flows through the catchment, rainfall run-off from urban and agricultural areas carries sediments, pesticides, and other chemicals into river systems, which lead to coastal waters. The impact of the Kosovo crisis on the Danube ecosystems provides a poignant example of the effects of such diffused pollution mechanisms and reveals a number of interesting pollution mechanisms. This paper discusses both the effects of diffused pollution on the Black Sea, drawing from state-of-the-art reports on the Danube, and proposes a framework for a decision support system based on distributed hydrological and pollution transport simulation models and GIS. The use of ecological health indicators and fuzzy inference supporting decisions on regional planning within this framework is also advocated. It is also argued that even the recently produced GEF document on Black Sea protection scenarios should benefit significantly if the concept of pollution reduction from both urban, industrial and rural areas should undergo a systematic conceptual update in the view of the recent recommendations of the UNEP IETC (2000) document.


1996 ◽  
Vol 7 (5) ◽  
pp. 381-388 ◽  
Author(s):  
S. G. Boguslavsky ◽  
S. T. Kaminsky ◽  
I. K. Ivashchenko
Keyword(s):  

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