scholarly journals Benthic microalgae community response to flooding in a tropical salt flat

2016 ◽  
Vol 76 (3) ◽  
pp. 577-582 ◽  
Author(s):  
L. S. M. Masuda ◽  
A. Enrich-Prast
Keyword(s):  
Sea Water ◽  
Shannon Index ◽  
Community Response ◽  
Microbial Mat ◽  
Total Density ◽  
Experimental Conditions ◽  
Effect Of Water ◽  
Salt Flat ◽  
Field Samples ◽  
Order Of Magnitude

Abstract This research evaluated the effect of flooding on the microphytobenthos community structure in a microbial mat from a tropical salt flat. Field samples were collected during four consecutive days: on the first three days the salt flat was dry, on the fourth day it was flooded by rain. In order to evaluate the community maintained in flood conditions, samples from this area were collected and kept in the laboratory for 10 days with sea water. The results of total abundance of microphytobenthos varied from 4.2 × 108 to 2.9 × 109 organisms L–1, total density increased one order of magnitude under the effect of water for both situations of precipitation in the salt flat and in experimental conditions, an increase due to the high abundance of Microcoleus spp. Shannon index (H’) was higher during the desiccation period. Our data suggest that changes in the abundance of organisms were due to the effect of water. The dominance of the most abundant taxa remained the same under conditions of desiccation and influence of water, and there is probably a consortium of microorganisms in the microbial mat that helps to maintain these dominances.

Characteristics of Sea-Water Ice Slurry for Cooling of Fish

2013 ◽  
Vol 388 ◽  
pp. 123-127 ◽  
Author(s):  
Agus Sunjarianto Pamitran ◽  
Helmi Dadang Ardiansyah ◽  
Mach Novviali
Keyword(s):  
Solid Surface ◽  
Chemical Equilibrium ◽  
Sea Water ◽  
Freezing Point ◽  
Good Time ◽  
Ice Slurry ◽  
High Quality ◽  
Experimental Conditions ◽  
Water Ice ◽  
Cooling Method

A more effective of cooling method is necessary for fish storage to get high quality and long freshness of fish. Ice block is not sufficient for fish storage because of its hard-solid surface that can damage the fish. Moreover for some remote area it is difficult to find ice block in good time with reasonable/low price. One solution for this problem is the using of sea-water ice slurry for fish cooling. Ice slurry is formed when the sea-water temperature goes down to its freezing point, when the early nucleation is formed. Crystal ice can be formed when chemical equilibrium is occurred. The purpose of this present study is to observe the characteristics of ice slurry generation using scraper blade evaporator and orbital rod evaporator. The experiment is done under some experimental conditions.

scholarly journals Evaluation of the Biodegradation of Petroleum Contaminants by Pseudomonas Aeruginosa in the Caspian Sea Coastline Waters

2019 ◽  
Vol 13 (3) ◽  
pp. 21-26
Author(s):  
Samira Mehrdad ◽  
◽  
Keivan Saeb ◽  
Lobat Taghavi ◽  
Masood Ghane ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Caspian Sea ◽  
Sea Water ◽  
Culture Media ◽  
Total Petroleum Hydrocarbons ◽  
The Caspian Sea ◽  
Experimental Conditions ◽  
Sustainable Resources ◽  
Life On Earth ◽  
Predominant Strain

Background: Water plays an essential role in supporting life on earth and sea worldwide, requiringclean, safe, high quality and sustainable resources. Nowadays, many water resources have been contaminatedwith toxic compounds originating from petroleumdue to economical and industrial developments. There is anurgent need to clean up the waters with environmentally friendlyand inexpensive methods. This study investigated the biodegradation of total petroleum hydrocarbons (TPH) using Pseudomonas aeruginosa (P. aeruginosa) in southern Caspian Sea coastline. Methods: Coastline sediment samples were collected, with P. aeruginosa being the predominant strain. The bacteria were cultured in triplicates in the presence of 0.5, 1, 2 and 4% of gasoline andunder specific experimental conditions of varying temperature, pH, salinity, shaker speed, and incubation periods. The data representing the gasoline biodegradation in the samples were statistically analyzed. Results: At optimized experimental conditions for temperature, pH, salinity, incubation period, and shaker speed, maximum biodegradation of TPH was achieved by culturing P. aeruginosa strains with the sea water samples containing varying concentrations of gasoline. Conclusion: The gram-negative bacteria, P. aeruginosa, almost completely biodegraded TPH contaminants from the samples’ culture media over 28 days of incubation. We conclude that the use of P. aeruginosa is an efficient method for the biodegradation of Caspian coastal waters contaminated with TPH.

scholarly journals Assessment of Sal Seedlings and Herbaceous Flora in the Khairbar Plantation of Sarguja Forest Division, Chhattisgarh

2015 ◽  
Vol 10 (1) ◽  
pp. 330-337 ◽  
Author(s):  
R Sinha ◽  
M Jhariya ◽  
D Yadav
Keyword(s):  
Growth Performance ◽  
Shannon Index ◽  
Tropical Species ◽  
Good Growth ◽  
Total Density ◽  
Herbaceous Species ◽  
Root Shoot Ratio ◽  
Forest Division ◽  
Collar Diameter ◽  
Herb Species

In the present study an attempt has been made to evaluate the growth performance of sal seedlings and also assess the diversity of herbaceous flora in the Khairbar plantation of Sarguja forest division during the year 2013-14. Study reveals that there are prominent variations in the height of the seedlings in Khairbar plantation. The root shoot ratio of seedlings ranged between 0.31 to 0.74. The total height of seedlings ranged from 24.00 to 90.00 cm. The girth of individual seedling ranged between 4.00 and 12.00 cm. The number of branches per seedling ranged between 4.00-17.00. The average collar diameter of sal seedling was 1.96 cm and the sturdiness ranged from 15.09-42.86. Total of 27 herbaceous species comprising 15 families were encountered in the study area. The total density of the herb species was 776000 individuals ha-1 and the maximum density was recorded for Mellilotus alba (64000 individuals ha-1), while minimum for Achyranthus aspera, Malvastrum coromandelicum and Rumex dentatus (12000 individuals ha-1 for each). The Shannon index (H’) of herbaceous species was 4.606, Simpson index (Cd) was 0.045, Species richness (d) was 1.917 and Equitability (e) was 1.397, respectively. It was observed that the growth performance of sal seedling in the Khairbar plantation site is quiet slow as compared to the other tropical species. It may also be due to the higher population of the herbaceous species. The herbaceous species compete with the sal species for the sharing of the resources for the growth and development. Micro climate and management aspects are the major concern for the good growth performance of the species in plantation sites.

scholarly journals The Seasonal Cycle of Upper-Ocean Mixing at 8°N in the Bay of Bengal

2020 ◽  
Vol 50 (2) ◽  
pp. 323-342 ◽  
Author(s):  
D. A. Cherian ◽  
E. L. Shroyer ◽  
H. W. Wijesekera ◽  
J. N. Moum
Keyword(s):  
Bay Of Bengal ◽  
Seasonal Cycle ◽  
Sea Water ◽  
Turbulent Transport ◽  
Low Frequency ◽  
Salt Flux ◽  
Strong Mixing ◽  
Northeast Monsoon ◽  
Order Of Magnitude ◽  
Episodic Mixing

AbstractWe describe the seasonal cycle of mixing in the top 30–100 m of the Bay of Bengal as observed by moored mixing meters (χpods) deployed along 8°N between 85.5° and 88.5°E in 2014 and 2015. All χpod observations were combined to form seasonal-mean vertical profiles of turbulence diffusivity KT in the top 100 m. The strongest turbulence is observed during the southwest and postmonsoon seasons, that is, between July and November. The northeast monsoon (December–February) is a period of similarly high mean KT but an order of magnitude lower median KT, a sign of energetic episodic mixing events forced by near-inertial shear events. The months of March and April, a period of weak wind forcing and low near-inertial shear amplitude, are characterized by near-molecular values of KT in the thermocline for weeks at a time. Strong mixing events coincide with the passage of surface-forced downward-propagating near-inertial waves and with the presence of enhanced low-frequency shear associated with the Summer Monsoon Current and other mesoscale features between July and October. This seasonal cycle of mixing is consequential. We find that monthly averaged turbulent transport of salt out of the salty Arabian Sea water between August and January is significant relative to local E − P. The magnitude of this salt flux is approximately that required to close model-based salt budgets for the upper Bay of Bengal.

Effects of organic solutes on the Raman spectra of barnacle muscle fibers

1987 ◽  
Vol 65 (7) ◽  
pp. 1416-1420 ◽  
Author(s):  
Jean-Pierre Caillé ◽  
Marie Pigeon-Gosselin ◽  
Michel Pézolet
Keyword(s):  
Raman Spectra ◽  
Sea Water ◽  
Muscle Fibers ◽  
Extraction Procedure ◽  
Organic Solutes ◽  
Experimental Conditions ◽  
Scattering Intensity ◽  
Barnacle Muscle ◽  
Α Helix ◽  
Barnacle Muscle Fibers

The Raman spectra observed from barnacle muscle fibers are quite complex because the cytoplasm of these cells contains several proteins and solutes. An extraction procedure was used to separate organic solutes from the contractile proteins. Glycine, trimethylamine oxide, taurine, and alanine were found to contribute to the Raman spectra of barnacle muscle fibers, while spectra of lobster fibers reveal the presence of betaine in addition. We have observed that the increase in osmolarity of the intracellular fluid caused by the augmentation of the salinity of sea water (density, 1.023–1.030) in which the barnacles were kept, induces a reduction of intensity of the amide I band. To distinguish among the different parameters which are modified by the sea water salinity, observations were made on glycerinated barnacle muscle fibers. The reduction of intensity of the amide I band in the Raman spectra of glycerinated muscle fibers was also observed with the addition of taurine (0.08 M) in the external relaxing solution. Therefore, under these experimental conditions, the Raman scattering intensity in the amide I region assigned to the α-helix conformation (1645–1650 cm−1) is increased when the concentration of organic electrolytes is reduced. However, as no significant decrease of the scattering intensity in the 1660–1670 cm−1 region where the amide I bands of either β-sheet or disordered conformations normally appear was observed, the increase of intensity of the amide I band centered at 1645 cm−1 is assigned to a change of orientation of α-helical segments of the myosin molecules. Our results suggest that organic solutes influence the position of the S-2 segments relative to the thick filaments.

Interaction between atomic hydrogen and YBa2Cu3O7

1992 ◽  
Vol 7 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
Angel L.G. Ponce ◽  
Jose J. Fripiat
Keyword(s):  
Induction Period ◽  
Atomic Hydrogen ◽  
Dissociative Chemisorption ◽  
Experimental Conditions ◽  
Reaction Proceeds ◽  
Order Of Magnitude ◽  
O Vacancy ◽  
The Creation ◽  
Approximate Limit

Atomic hydrogen obtained from dissociative chemisorption of molecular H2 on Pt particles deposited on the surface of YBa2Cu3O7 reacts with the oxide in producing O vacancies and intercalating H at 82 °C under a H2 pressure of about 400 Torr. An induction period which extends over 1 h is observed as long as the concentration in O vacancies is below 0.1. Above this approximate limit the reaction proceeds quickly until about 1 mol H2 has been consumed. It then slows down progressively, but it is not completed even after 27 h of reaction and ∼1.4 H2 consumed, under these experimental conditions. The enthalpy for the creation of the O vacancy is 143 kcal/g mol O, while the H intercalation enthalpy is −57.5 kcal/g mol H. It appears that the reaction of molecular H2 over YBa2Cu3O7 not coated with Pt proceeds similarly, but the rate is nearly one order of magnitude slower, under identical conditions. The stoichiometry of the reaction agrees with the earlier suggestion that O1 is a labile oxygen which can be replaced by intercalated H. This site and the interstitial vacant sites in the copper chains square plane would be the first ones to be occupied by intercalated H.

scholarly journals Carbon monoxide apparent quantum yields and photoproduction in the Tyne estuary

2011 ◽  
Vol 8 (3) ◽  
pp. 703-713 ◽  
Author(s):  
A. Stubbins ◽  
C. S. Law ◽  
G. Uher ◽  
R. C. Upstill-Goddard
Keyword(s):  
Carbon Monoxide ◽  
Natural Waters ◽  
Sea Water ◽  
River Estuary ◽  
Quantum Yields ◽  
Absorption Data ◽  
Coastal Sea ◽  
Order Of Magnitude ◽  
Good Proxy ◽  
Minimum Estimate

Abstract. Carbon monoxide (CO) apparent quantum yields (AQYs) are reported for a suite of riverine, estuarine and sea water samples, spanning a range of coloured dissolved organic matter (CDOM) sources, diagenetic histories, and concentrations (absorption coefficients). CO AQYs were highest for high CDOM riverine samples and almost an order of magnitude lower for low CDOM coastal seawater samples. CO AQYs were between 47 and 80% lower at the mouth of the estuary than at its head. Whereas, a conservative mixing model predicted only 8 to 14% decreases in CO AQYs between the head and mouth of the estuary, indicating that a highly photoreactive pool of terrestrial CDOM is lost during estuarine transit. The CDOM absorption coefficient (a) at 412 nm was identified as a good proxy for CO AQYs (linear regression r2 > 0.8; n = 12) at all CO AQY wavelengths studied (285, 295, 305, 325, 345, 365, and 423 nm) and across environments (high CDOM river, low CDOM river, estuary and coastal sea). These regressions are presented as empirical proxies suitable for the remote sensing of CO AQYs in natural waters, including open ocean water, and were used to estimate CO AQY spectra and CO photoproduction in the Tyne estuary based upon annually averaged estuarine CDOM absorption data. A minimum estimate of annual CO production was determined assuming that only light absorbed by CDOM leads to the formation of CO and a maximum limit was estimated assuming that all light entering the water column is absorbed by CO producing photoreactants (i.e. that particles are also photoreactive). In this way, annual CO photoproduction in the Tyne was estimated to be between 0.99 and 3.57 metric tons of carbon per year, or 0.004 to 0.014% of riverine dissolved organic carbon (DOC) inputs to the estuary. Extrapolation of CO photoproduction rates to estimate total DOC photomineralisation indicate that less than 1% of DOC inputs are removed via photochemical processes during transit through the Tyne estuary.

scholarly journals Tracer and Nontracer Potassium Fluxes in Squid Giant Axons and the Effects of Changes in External Potassium Concentration and Membrane Potential

1967 ◽  
Vol 50 (3) ◽  
pp. 533-549 ◽  
Author(s):  
R. A. Sjodin ◽  
L. J. Mullins
Keyword(s):  
Sea Water ◽  
Specific Activity ◽  
Membrane Conductance ◽  
Giant Axon ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Experimental Conditions ◽  
Potassium Efflux ◽  
Potassium Loss ◽  
Independence Principle

The efflux of labeled and unlabeled potassium ions from the squid giant axon has been measured under a variety of experimental conditions. Axons soaked in sea water containing 42K ions lost radioactivity when placed in inactive sea water according to kinetics which indicate the presence of at least two cellular compartments. A rapidly equilibrating superficial compartment, probably the Schwann cell, was observed to elevate the specific activity of 42K lost from such axons to K-free sea water for a period of hours. The extra radioactive potassium loss from such axons during stimulation, however, was shown to have a specific activity identical within error to that measured in the axoplasm at the end of the experiment. The same was shown for the extra potassium loss occurring during passage of a steady depolarizing current. Axons placed in sea water with an elevated potassium ion concentration (50 mM) showed an increased potassium efflux that was in general agreement with the accompanying increase in membrane conductance. The efflux of potassium ions observed in 50 mM K sea water at different membrane potentials did not support the theory that the potassium fluxes obey the independence principle.

scholarly journals The legacy of deer overabundance: long-term delays in herbaceous understory recovery

2016 ◽  
Vol 46 (3) ◽  
pp. 362-369 ◽  
Author(s):  
Thomas H. Pendergast ◽  
Shane M. Hanlon ◽  
Zachary M. Long ◽  
Alejandro A. Royo ◽  
Walter P. Carson
Keyword(s):  
Community Composition ◽  
Community Response ◽  
Forest Understory ◽  
Total Density ◽  
Eastern United States ◽  
Legacy Effect ◽  
Browse Species ◽  
Understory Communities ◽  
Open Question ◽  
And Control

Decades of white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) overpopulation have dramatically homogenized forests across much of the eastern United States, creating depauperate forest understory communities. The rate at which these communities recover once deer browsing has been reduced remains an open question. We evaluate overbrowsing legacy effects by examining how forest herbaceous layers respond in terms of biodiversity, density, and community composition over 11 years using exclosures and control plots within a mature beech–maple forest. Although little recovery occurred in the first 5 years, total density and preferred browse density rebounded substantially during the final years of the study. Although community composition began to diverge between exclosure and control plots after 5 years, diversity failed to recover even after 11 years of excluding browsers. Our findings show that vulnerable species can increase after excluding browsers but only if those species were initially present. Biodiversity recovery may be extremely slow because preferred browse species have been nearly extirpated from many forests and thus are unable to recruit into refugia. We empirically demonstrate the extent of the ghost of herbivory past or legacy effect of browsing, i.e., the substantial time delay between herbivore abatement and community response after decades of high deer densities.

scholarly journals Note on the Regeneration of the Gill of Mytilus edulis

1931 ◽  
Vol 17 (2) ◽  
pp. 551-566 ◽  
Author(s):  
D. Atkins
Keyword(s):  
Food Supply ◽  
General Circulation ◽  
Sea Water ◽  
The Other ◽  
Experimental Conditions ◽  
Cut Edge ◽  
Retarding Effect ◽  
Gill Filaments ◽  
Food Groove ◽  
Optimum Salinity

Experiments have shown that the gill of Mytilus is capable of regeneration, and that this may occur in less than eight months. It may be confined to the formation of a food grove at the cut edge of the gill, without appreciable regeneration in length of the gill filaments. Regeneration of a food groove appears always to occur at the cut edge, if the ends of the descending and ascending filaments are able to touch and so to fuse. On the other hand, regeneration of gill filaments does not seem to occur invariably, and when it does the rate is slow, at least under experimental conditions and in mussels of a length of about 7·0 to 8·0 cm., such as were used for the experiments: it is possible that regeneration would occur more surely and rapidly in young mussels, but owing to the thinness of the shell they would be more difficult to wedge open without fracturing. Coulthard (6, p. 136), however, says that “The rate of growth is independent of size in the mussel, being apparently influenced only by the environment.” Perhaps the lack of an abundant food supply under the conditions of the experiments should be taken into consideration, though it is well known that in general the amount of food available to an animal has little influence on regeneration (9, p. 27). The salinity of the water in general circulation is about 36–37°/oo, that is, higher than normal sea-water, which is about 35°/oo, and would be considerably higher than the optimum salinity for growth (see Flattely and Walton, 7, p. 81). This may also possibly have a retarding effect on the initiation of regeneration and the rate.

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