Assessment of Spatiotemporal Phytoplankton Composition in Relation to Environmental Conditions of Gorgan Bay, Iran

2018 ◽  
Vol 42 (1) ◽  
pp. 173-189 ◽  
Author(s):  
Zohreh Mazaheri Kouhanestani ◽  
Daniel L. Roelke ◽  
Rasoul Ghorbani ◽  
Masami Fujiwara
Keyword(s):  
Environmental Conditions ◽  
Phytoplankton Composition ◽  
Gorgan Bay

INVESTIGATION OF PHYTOPLANKTON COMMUNITY IN “YEREVANYAN LICH” RESERVOIR AND THE HRAZDAN RIVER IN THE CONDITIONS OF ALGAL BLOOM

2019 ◽  
Vol 53 (3 (250)) ◽  
pp. 200-205
Author(s):  
A.S. Mamyan ◽  
L.G. Stepanyan ◽  
L.R. Hambaryan ◽  
V.M. Varagyan ◽  
G.A. Gevorgyan
Keyword(s):  
Environmental Conditions ◽  
Phytoplankton Community ◽  
Algal Bloom ◽  
Phytoplankton Composition ◽  
Dominant Complex

Phytoplankton quantitative and qualitative parameters in “Yerevanyan Lich” Reservoir and the Hrazdan River were investigated in April and June–August 2015. The results of the study showed that algal bloom registered in “Yerevanyan Lich” Reservoir in summer 2015 created new environmental conditions which led to significant changes in reservoir’s phytoplankton dominant complex, affecting also phytoplankton composition in the Hrazdan River sites located downstream from the reservoir.

Changes in phytoplankton composition of the Golden Horn Estuary (Sea of Marmara) following remediation

2020 ◽  
Vol 100 (7) ◽  
pp. 1053-1062
Author(s):  
Seyfettin Tas
Keyword(s):  
Species Diversity ◽  
Dissolved Oxygen ◽  
Environmental Conditions ◽  
Secchi Depth ◽  
Water Transparency ◽  
Phytoplankton Composition ◽  
Number Of Species ◽  
Relative Contribution ◽  
Golden Horn ◽  
Golden Horn Estuary

AbstractChanges in phytoplankton composition of the Golden Horn Estuary were investigated following remediation, through seawater transfer from the Strait of Istanbul to the estuary. Average values of Secchi depth, salinity and dissolved oxygen increased during this study when compared with a previous study. The average number of species (S) and species diversity (H′) increased and they correlated positively with Secchi depth, salinity and dissolved oxygen. There was a similar phytoplankton group composition between this and a previous study, however, the species composition differed. A total of 127 taxa consisting of diatoms (66 taxa), dinoflagellates (49 taxa) and others (12 taxa) were identified. Abundance of dinoflagellates and phytoflagellates and their relative contribution to the total phytoplankton abundance increased during this study, however, the abundance of diatoms and their relative contribution decreased notably, as compared with the previous study. There was a significant positive correlation between salinity and dinoflagellates and phytoflagellates (P < 0.01), and also between Secchi depth and dinoflagellates (P < 0.01) in the upper estuary. Additionally, salinity and Secchi depth correlated positively with species diversity (H′) and number of species (S) (P < 0.01). The increase in water transparency probably contributed to the increase in abundance of dinoflagellates and phytoflagellates. The results revealed that water transparency was one of the most important factors affecting phytoplankton composition in the study area. Changes in some environmental conditions following seawater transfer appear to have changed phytoplankton composition. As a result, phytoplankton species were confirmed as a very good indicator of changed environmental conditions.

Spatial distribution and biodiversity of macrofauna in the southeast of the Caspian Sea, Gorgan Bay in relation to environmental conditions

2012 ◽  
Vol 47 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Mehrshad Taheri ◽  
Maryam Yazdani Foshtomi ◽  
Majid Noranian ◽  
Seyed Sahab Mira
Keyword(s):  
Spatial Distribution ◽  
Environmental Conditions ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Gorgan Bay

scholarly journals Algal pigments in Hornsund (Svalbard) sediments as biomarkers of Arctic productivity and environmental conditions

2017 ◽  
Vol 38 (4) ◽  
pp. 423-443 ◽  
Author(s):  
Magdalena Krajewska ◽  
Małgorzata Szymczak-Żyła ◽  
Grażyna Kowalewska
Keyword(s):  
Primary Production ◽  
Water Column ◽  
Environmental Conditions ◽  
Intertidal Zone ◽  
Surface Sediments ◽  
Solar Irradiation ◽  
The Arctic ◽  
Total Biomass ◽  
Phytoplankton Composition ◽  
Algal Pigments

AbstractPigments (chloropigments-a and carotenoids) in sediments and macroalgae samples, collected in Hornsund, in July 2015 and July 2016, were analysed (HPLC) in this work. In spite of the aerobic conditions and the periodic intensive solar irradiation in the Arctic environment, neither of which favour pigment preservation in water column and surface sediments, our results indicate that these compounds can provide information about phytoplankton composition, primary production and environmental conditions in this region. The sum of chloropigments-a, a marker of primary production, in the Hornsund sediments varied from 0.40 to 14.97 nmol/g d.w., while the sum of carotenoids ranged from 0.58 to 8.08 nmol/g d.w. Pheophorbides-a and pyropheophorbides-a made up the highest percentage in the sum of chloropigments-a in these sediments, supplying evidence for intensive zooplankton and/or zoobenthos grazing. Among the carotenoids, fucoxanthin and its derivatives (19’-hexanoyloxyfucoxanthin and 19’-hexanoyloxy-4-ketofucoxanthin) contributed the highest percentage, which points to the occurrence mainly of diatoms and/or haptophytes in the water. The pigment markers show that the input of macroalgae to the total biomass could be considerable only in the intertidal zone.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

The influence of external conditions on sound pressure in the pistonphone at the infrasound frequency range

2020 ◽  
pp. 67-72
Author(s):  
A. V. Konkov ◽  
D. V. Golovin
Keyword(s):  
Environmental Conditions ◽  
Sound Pressure ◽  
Primary Method ◽  
Frequency Range ◽  
External Conditions ◽  
Numerical Estimations

The influence of environmental conditions on a sound pressure reproduced by the primary method in the measuring chambers of the Pistonphone in the frequency range from 1 mHz to 250 Hz is estimated. Numerical estimations of influence of environmental conditions on sound pressure in pistonphone measuring chambers are given and special requirements to system of maintenance of required external conditions are specified.

Disentangling the role of shared ancestry and the environment on leaf stable isotopes

2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1
Keyword(s):  
Stable Isotopes ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Environmental Control ◽  
Phylogenetic Signal ◽  
Individual Species ◽  
Habitat Types ◽  
Δ13c And Δ15n ◽  
Environmental Controls ◽  
Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

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