scholarly journals Comparison of benthic diatom community structures on natural and artificial substrates in marine lake (Adriatic Sea)

2021 ◽  
Vol 62 (1) ◽  
pp. 21-44
Author(s):  
Ana Car ◽  
Cüneyt Nadir Solak ◽  
Stijepo Ljubimir ◽  
Aydin Kaleli ◽  
Iris Dupčić Radić ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Sampling Site ◽  
Microscopic Analysis ◽  
Dead Sea ◽  
Artificial Substrates ◽  
Diatom Community ◽  
Shallow Marine ◽  
Diatom Communities ◽  
Light Microscopic Analysis ◽  
First Time

In this study, the diatoms of three alternative habitats (epilithon, epiphyton and artificial sub-strate) were compared to understand the differences in composition on artificial and natural sub-strates. For this purpose, the samples were collected weekly between 11th August and 2nd Septem-ber 2016 at a sampling site in a shallow marine lake, Mrtvo More (Dead Sea) on Lokrum Island near Dubrovnik (South Adriatic, Croatia). In addition to detailed light microscopic analysis, ultrastructural analysis of benthic diatoms from Lake Mrtvo More was performed for the first time using scanning electron microscopy (SEM). A total of 97 taxa were identified in 12 samples. Cocconeis scutellum Ehrenberg and Halamphora coffeiformis (C.Agardh) Levkov were the most frequent taxa in the samples. Shannon-Wiener diver-sity index (H’) values varied from 1.78 (in September on Padina sp.) to 4.52 (in August on glass). According to non-metric multidimensional scaling ordination, there were two groups: epilithon and artificial glass substrate as Group1 and macroalgae as Group2. The results of the analysis showed that the diatom communities developing on artificial sub-strates accurately correspond to the diatom community of a rock substrate and thus can be used as a representative alternative tool for studies of epilithic diatoms in further experiments.

scholarly journals Epilithic Diatom Community Shows a Higher Vulnerability of the River Sava to Pollution during the Winter

Diversity ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 465
Author(s):  
Igor Zelnik ◽  
Tjaša Sušin
Keyword(s):  
Power Plants ◽  
Abiotic Factors ◽  
Sampling Site ◽  
Hydroelectric Power ◽  
Diatom Community ◽  
Nitrogen And Phosphorus ◽  
Sava River ◽  
Diatom Communities ◽  
Epilithic Diatom ◽  
The Sava River

The aim of the research was to investigate the influence of environmental factors on the structure of epilithic diatom communities in the Sava River from the source to the state border 220 km downstream. The river had numerous human influences along its course, such as municipal and industrial wastewater, agriculture, hydroelectric power plants, etc. The main objective of the research was to find out the influence of human pressure on the structure of the epilithic diatom community under winter and summer conditions. Winter and summer samples were taken at nine sites. At each sampling site, a set of abiotic factors was measured and another set of environmental parameters was evaluated. The analyses showed that nitrogen and phosphorus concentrations increased downstream. We identified 118 different species of diatoms. The most common taxa were Achnanthidium minutissimum and A. pyrenaicum. Planktonic species Cyclotella meneghiniana was only found in the samples of the lower part of the Sava, which is unusual for the epilithic community. The composition of the epilithic diatom community was significantly influenced by conductivity and water temperature, pH and distance from the source. The similarity between diatom communities closer to the source of the river was higher than between communities from the lower part of the Sava River. The values of the trophic and saprobic indices increased downstream and showed that the pollution of the river with nutrients and organic matter increases with the distance from the source. Both indices were significantly higher in winter and showed a more impaired river ecosystem during the winter.

scholarly journals Additional study of the morphology of eggs and miracidia of Eurytrema coelomaticum (Trematoda)

2015 ◽  
Vol 52 (3) ◽  
pp. 244-251 ◽  
Author(s):  
J. Pinheiro ◽  
D. O. Franco-Acuña ◽  
A. Oliveira-Menezes ◽  
S. V. P. B. Brandolini ◽  
F. A. O. Adnet ◽  
...  
Keyword(s):  
Ciliated Cell ◽  
Polarized Light ◽  
Microscopic Analysis ◽  
Freeze Substitution ◽  
The Body ◽  
Maturation Stage ◽  
Bright Field ◽  
Larval Body ◽  
Light Microscopic Analysis ◽  
First Time

Abstract The morphology of the eggs and miracidia of Eurytrema coelomaticum was analyzed. The eggshell presented different composition according to the maturation stage of the egg, as seen by distinct birefringence after polarized light microscopic analysis. Detailed morphology of the brownish eggs, measuring 44.97±3.83 (38.67 - 51.40) μm in length and 30.71±2.54 (25.79 -34.47) μm in width, and the different electrondensities of the inner, middle and outer layers of the eggs were determined using light (bright field and DIC) and electronic microscopy (scanning and transmission). The morphometry of the eggs is in accordance to those measures presented in previous studies. The miracidia were observed using light microscopy, inside and outside the egg. It was possible to observe the terebratorium at the anterior end of the body, the ciliated epidermal plates, placed according the formula E=2E1 + 2E2, and the interepidermal ridge, but eyespots were not observed. The excretory vesicle was laterally placed in the posterior middle of the body and the germ balls were observed. The miracidium inside the egg was observed by routine techniques, but the miracidium was not well preserved. Thus, the eggs were processed using high pressure-freeze substitution technique and reasonable preservation was achieved. The cilia covering the larval body, with a typical ciliary organization, the terebratorium with folds and the junction of the epidermal ciliated cell with the larval body were seen. For the first time detailed information on the eggs and miracidia of E. coelomaticum is given, which can be the basis for new studies.

scholarly journals New Geographical Record of Three Cumacean Species Eudorella nana, Leucon affinis, Leucon siphonatus and One Rare Amphipod Presence Confirmation, Stenothoe bosphorana, in Adriatic Sea, Italy

2021 ◽  
Author(s):  
P. Strafella ◽  
V. Salvalaggio ◽  
C. Cuicchi ◽  
E. Punzo ◽  
A. Santelli ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Geographical Record ◽  
New Geographical Record ◽  
First Time ◽  
Adriatic Basin

AbstractThree cumacean species, Eudorella nana Sars, 1879, Leucon affinis Fage, 1951, Leucon siphonatus Calman, 1905, were recorded for the first time and one rare amphipod presence, Stenothoe bosphorana Sowinsky, 1898, was confirmed in the Adriatic basin.

scholarly journals Hydrostatic Densitometer for Monitoring Density in Freshwater to Hypersaline Water Bodies

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1842
Author(s):  
Ziv Mor ◽  
Hallel Lutzky ◽  
Eyal Shalev ◽  
Nadav G. Lensky
Keyword(s):  
Continuous Monitoring ◽  
Pressure Sensors ◽  
Temporal Variations ◽  
Dead Sea ◽  
Conductivity Measurements ◽  
Lake Levels ◽  
Density Profiles ◽  
Water Column Stratification ◽  
Hypersaline Water ◽  
First Time

Density, temperature, salinity, and hydraulic head are physical scalars governing the dynamics of aquatic systems. In coastal aquifers, lakes, and oceans, salinity is measured with conductivity sensors, temperature is measured with thermistors, and density is calculated. However, in hypersaline brines, the salinity (and density) cannot be determined by conductivity measurements due to its high ionic strength. Here, we resolve density measurements using a hydrostatic densitometer as a function of an array of pressure sensors and hydrostatic relations. This system was tested in the laboratory and was applied in the Dead Sea and adjacent aquifer. In the field, we measured temporal variations of vertical profiles of density and temperature in two cases, where water density varied vertically from 1.0 × 103 kg·m−3 to 1.24 × 103 kg·m−3: (i) a borehole in the coastal aquifer, and (ii) an offshore buoy in a region with a diluted plume. The density profile in the borehole evolved with time, responding to the lowering of groundwater and lake levels; that in the lake demonstrated the dynamics of water-column stratification under the influence of freshwater discharge and atmospheric forcing. This method allowed, for the first time, continuous monitoring of density profiles in hypersaline bodies, and it captured the dynamics of density and temperature stratification.

scholarly journals Collagen content and distribution in the normal and transplanted human heart: A postmortem quantitative light microscopic analysis

1996 ◽  
Vol 5 (2) ◽  
pp. 61-68 ◽  
Author(s):  
R.J. van Suylen ◽  
E.E.C. van Bekkum ◽  
H. Boersma ◽  
L.B. de Kok ◽  
A.H.M.M. Balk ◽  
...  
Keyword(s):  
Human Heart ◽  
Microscopic Analysis ◽  
Collagen Content ◽  
Light Microscopic Analysis

Light microscopic analysis of the gravireceptor in Xenopus larvae developed in hypogravity

1989 ◽  
Vol 9 (11) ◽  
pp. 241-244 ◽  
Author(s):  
W. Briegleb ◽  
J. Neubert ◽  
A. Schatz ◽  
B. Kruse
Keyword(s):  
Microscopic Analysis ◽  
Light Microscopic Analysis

scholarly journals Amazing Discoveries of Benthic Fauna from the Abyssal Zone of Lake Baikal

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 972
Author(s):  
Ilya Kondratov ◽  
Tatiana Sitnikova ◽  
Irina Kaygorodova ◽  
Natalia Denikina ◽  
Vadim Annenkov ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Molecular Genetic ◽  
Benthic Fauna ◽  
Molecular Genetic Analysis ◽  
Artificial Substrates ◽  
Plastic Substrate ◽  
Freshwater Ecosystem ◽  
Abyssal Zone ◽  
First Time ◽  
Natural Laboratory

Lake Baikal is a natural laboratory for the study of species diversity and evolution, as a unique freshwater ecosystem meeting the all of the main criteria of the World Heritage Convention. However, despite many years of research, the true biodiversity of the lake is clearly insufficiently studied, especially that of deep-water benthic sessile organisms. For the first time, plastic waste was raised from depths of 110 to 190 m of Lake Baikal. The aim of this study was to examine the biological community inhabiting the plastic substrate using morphological and molecular genetic analysis. Fragments of plastic packaging materials were densely populated: bryozoans, leeches and their cocoons, capsules of gastropod eggs, and turbellaria cocoons were found. All the data obtained as a result of an analysis of the nucleotide sequences of the standard bar-coding fragment of the mitochondrial genome turned out to be unique. Our results demonstrate the prospects for conducting comprehensive studies of artificial substrates to determine the true biodiversity of benthos in the abyssal zone of Lake Baikal.

Dactyloidites ottoi (Geinitz, 1849) in Bahamian Pleistocene Carbonates: A Shallowest-marine Indicator

2021 ◽  
pp. SP522-2021-69
Author(s):  
H. Allen Curran ◽  
Bosiljka Glumac
Keyword(s):  
Late Pleistocene ◽  
Carbonate Sediments ◽  
The Bahamas ◽  
Shallow Marine ◽  
Fine Detail ◽  
Plant Remains ◽  
Mis 5E ◽  
Deposit Feeding ◽  
First Time ◽  
Host Sediment

AbstractThe rosetted trace fossil Dactyloidites ottoi (Geinitz, 1849) is reported and described for the first time from late Pleistocene (MIS 5e) carbonates of the Bahama Archipelago in shallowing-upward, shelly calcarenites from Great Inagua and Great and Little Exuma islands. The distinctive, fan-shaped D. ottoi specimens from the Bahamas, while not preserved in fine detail and not revealing a shaft, compare favourably in shape and size with specimens from other localities around the world, including the oldest well-documented specimens from the Jurassic of Argentina. D. ottoi is interpreted as a fodinichnion formed by the activity of a deposit-feeding worm, probably a polychaete, consuming marine-plant remains within host sediment. The late Pleistocene palaeodepositional environment of these carbonate sediments is interpreted as within the lower foreshore-upper shoreface zone in full marine, tropical waters. This discovery of D. ottoi marks an addition to the Bahamian shallow-marine ichnocoenose within the Skolithos ichnofacies.

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