Diurnal changes in oxygen content of the water over the coral reef platform at Heron I

1967 ◽  
Vol 18 (1) ◽  
pp. 23 ◽  
Author(s):  
DW Kinsey ◽  
E Kinsey
Keyword(s):  
Oxygen Content ◽  
High Tide ◽  
Spring Tide ◽  
Algal Species ◽  
Coral Growth ◽  
Diurnal Changes ◽  
Oxygen Levels ◽  
Production And Consumption ◽  
Early Afternoon ◽  
Reef Platform

Heron I., in the Australian Great Barrier Reef, is a small sand cay situated near the western end of a reef 6.5 miles long. The area investigated was south-west of the cay and approximately level, with extensive areas of living coral in the seaward half. Larger algal species were common near the cay but were not in evidence in the areas of active coral growth. Oxygen levels were determined without sampling using a membrane-enclosed polarographic probe. Results are presented as profiles across the platform and also as time sequences in the main draining channel. Some deep water results are included. Oxygen production and consumption were associated primarily with areas of rich coral growth and hence larger algae seemed unimportant in the overall oxygen exchange. Low tide oxygen levels in less than 1 ft of water ranged from 2.1 mg O2/l for a spring tide after midnight to more than 10.8 mg O2/l (the limit of the instrument) in the early afternoon. High tide levels in more than 6 ft of water ranged from 9.0 mg O2/l in the early afternoon to 6.4 mg O2/l 2hr after sunset. High tide readings were not taken late at night. There is some evidence that water already reduced or enriched in oxygen content on the previous tide was returned in significant quantities to the reef platform.

Diurnal Rhythms and Symptom Severity in Panic Disorder

1992 ◽  
Vol 161 (4) ◽  
pp. 512-516 ◽  
Author(s):  
Marilla F. Geraci ◽  
Thomas W. Uhde
Keyword(s):  
Panic Disorder ◽  
Panic Attacks ◽  
Diurnal Rhythms ◽  
Diurnal Changes ◽  
Phobic Anxiety ◽  
Early Afternoon ◽  
History Of ◽  
History Of Depression ◽  
Normal Controls ◽  
Or History

Diurnal changes in the frequency of panic attacks and symptoms of generalised anxiety, phobic anxiety and phobic avoidance in 34 panic-disorder patients and 40 normal controls were evaluated. The panic-disorder patients had significant diurnal changes in generalised and phobic anxiety, but not phobic avoidance. Increased severity of symptoms and prominent diurnal changes were most evident in the panic-disorder patients with a history of depression. Although panic attacks were distributed throughout the 24–hour period, patients with a current episode or history of depression tended to have more frequent panic attacks in the morning or early afternoon. These observations challenge the traditional belief that ‘anxious neurotic’ patients are relatively asymptomatic upon awakening in the morning and then develop more severe symptoms of anxiety later in the day.

scholarly journals DESIGN AND DEVELOPMENT OF OXYGEN MONITORING WITH GALVANIC OXYGEN SENSOR BASED ON MICROCONTROLLER ARDUINO UNO

2019 ◽  
Vol 1 (1) ◽  
pp. 5-7
Author(s):  
Budi Prijo Sembodo ◽  
Nanang Henri Vidal
Keyword(s):  
Oxygen Content ◽  
Oxygen Sensor ◽  
Descriptive Analysis ◽  
Health Sector ◽  
Exhaust System ◽  
Average Error ◽  
Oxygen Levels ◽  
Oxygen Analyzer ◽  
Arduino Uno ◽  
Oxygen Monitoring

The Oxygen Analyzer is a tool for measuring the oxygen content in a gas exhaust system. The Oxygen analyzer is used in various fields including the fields of industry and health. In the health sector, the Oxygen Analyzer is used to measure oxygen content in Continuous Positive Airway Pressure (CPAP), anesthetic machines, ventilator machines, or oxygen cylinders. In this study the researchers made an Oxygen Analyzer that can read oxygen levels 21% 100% with a reading range per digit. This study uses an oxygen sensor that serves to detect oxygen levels which is set with an Arduino Uno microcontroller. The testing is carried out directly on a ventilator as a comparison tool. The method of data analysis in this study uses descriptive analysis. In this study the tool created was able to detect the value of oxygen levels in the range of 21% - 100% with an average error of 0.01%.

scholarly journals Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

2010 ◽  
Vol 58 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Carlos Augusto França Schettini ◽  
Luiz Bruner de Miranda
Keyword(s):  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
High Tide ◽  
Spring Tide ◽  
Mixed Volume ◽  
Volume Transport ◽  
Tidal Variation ◽  
Salinity Stratification ◽  
Suspended Particulate ◽  
Matter Transport

The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1) and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.

scholarly journals Variation of water mass exchange on tidal scale in Balikpapan Bay

2021 ◽  
Vol 925 (1) ◽  
pp. 012013
Author(s):  
I P Anwar ◽  
M R Putri ◽  
A Tarya ◽  
I Mandang
Keyword(s):  
Mass Exchange ◽  
River Runoff ◽  
Water Mass ◽  
Model Simulation ◽  
Neap Tide ◽  
Saline Water ◽  
High Tide ◽  
Spring Tide ◽  
Salt Transport ◽  
Water Mass Exchange

Abstract Balikpapan Bay is enclosed water influenced by freshwater from river runoff and saline water from Makassar Strait. The exchange of water mass was examined by 3D numerical model simulation-Hamburg Shelf Ocean Model (HAMSOM) with horizontal resolutions approx. 150 m and 10 vertical layers applied in Balikpapan Bay. The thirteen tidal components, daily river runoff, atmospheric forcing, subsurface temperature, and Salinity in 3D used for model input. The tidal elevation from Geospatial Information Agency (BIG) model fits with this result from 01/03/2020 to 31/03/2020. It has coefficient correlation 0,99 with a significant level of 95% and Root Mean Square Error (RMSE) is 0,1 m. The volume and salt transport in the mouth (Line-A) and middle (Line-B) of bay was examined. The maximum transport in Line-A during spring (neap) high to low tide and low to high tide is −18364.72 m3/s (−1717.57 m3/s) and −17532.27 m3/s (4258.86 m3/s) for volume. Then, 531,947,898.90 kg.psu./s (−45,127,135.38 kg.psu./s) and −536,410,944.50 kg.psu./s (140,700,437.97 kg.psu./s) for salinity. Positive (negative) of water transport is inflow (outflow) to Balikpapan Bay. The net transport in a day during the spring (neap) is −832.45 m3/s (5976.43 m3/s) for volume and −4,463,045.58 kg.psu./s (185,827,573.35 kg.pau./s) for salt. The vertical structure of net volume and salt transport bot in Line-A and Line-B shows the water goes to outer bay in surface and inner bay in subsurface. While in the spring tide the surface deeper than neap tide. It indicated that water mass exchange dominantly influenced by river in surface and tidal in subsurface. It also shows that water mass from inner bay more easy flushing during spring tide than neap tide and vice versa

scholarly journals Some phenomena of magnetic disturbances at Kew

1910 ◽  
Vol 83 (566) ◽  
pp. 579-581
Keyword(s):  
The Other ◽  
Diurnal Changes ◽  
Vertical Force ◽  
Horizontal Force ◽  
Rapid Rise ◽  
Sunspot Maximum ◽  
Magnetic Elements ◽  
Early Afternoon ◽  
Phase Angles ◽  
Magnetic Disturbances

A recent paper discussed the diurnal inequality of Kew magnetic declination derived from 209 of the most highly disturbed days of the eleven years 1890 to 1900. The present paper discusses the corresponding phenomena for the same days in the other magnetic elements. The most prominent features of disturbed days are the irregular nature of magnetic changes, and the frequency of large oscillations. These more obvious features have hitherto engrossed attention. It is found, however, that the irregular changes on disturbed days are accompanied by large regular diurnal changes, which are specially striking in vertical force. In declination and horizontal force the range of the regular diurnal inequality on disturbed days is in the average month of the year about double that on quiet days, but in vertical force the former range is fully four times the latter. Disturbance affects the type as well as the range of the diurnal inequality. The former influence is comparatively small in horizontal force and the component to geographical north, larger in declination and the component to geographical west, and largest of all in vertical force. On quiet days the characteristic feature of the vertical force inequality is the fall in the forenoon to the minimum about 11 a. m. and the rapid rise in the early afternoon. Disturbed days, however, approach to a type in which there is a minimum about 4 a. m.— near the principal barometric minimum for the day—and a maximum at from 4 to 6 p. m. according to the season. The day rise and the night fall are about equally rapid. On disturbed days the shorter period Fourier “waves” in the diurnal inequality for V become of reduced importance relative to the 24-hour wave, and this wave has its phase some four hours earlier than on quiet days. Vertical force inequalities from the disturbed days of the four sunspot maximum years 1892—1895 show a considerably larger range than those from the whole 209 days, and their phase angles depart more from the phase angles for the quiet days of the eleven years.

Diurnal changes of stratification and photosynthesis in some tropical African waters

1957 ◽  
Vol 147 (926) ◽  
pp. 57-83 ◽  
Keyword(s):  
Oxygen Content ◽  
Thermal Stratification ◽  
Unit Volume ◽  
Open Water ◽  
Oxygen Depletion ◽  
Limited Range ◽  
Diurnal Changes ◽  
Order Of Magnitude ◽  
Many Sources ◽  
Isothermal Mixing

A description is given of diurnal changes, due to the photosynthesis of phytoplankton, in three shallow African waters. Their vertical distribution was largely controlled by changes of thermal stratification; examples corresponding to different degrees of the latter are illustrated from four series of observations. Thermal stratification was generally intermittent, with marked stratification during the day, ended by isothermal mixing at night. An effect of these changes upon the distribution of a blue-green alga, Anabaena , and its photosynthetic activity, is also illustrated. Experimental determinations of the rates of photosynthesis (as milligrams of oxygen produced per unit volume of water, or of algal cells, per hour), and their distribution with time and depth, were obtained using the classic method of suspended light and dark bottles. Photosynthetic behaviour generally resembled that found in temperate waters, but maximum rates of photosynthesis calculated per unit volume of algal cells were unusually high. The preceding observations are used to calculate rates of photosynthesis below unit area of water surface, both from the experimental results and from the diurnal variation of oxygen content in the open water. In the latter case the observed increase of oxygen content in a water column during daytime is corrected for sources of loss, due to respiration and exchange with the atmosphere, using a mean rate of oxygen depletion measured during the night. Although the method is subject to many sources of error, which are discussed, the conclusion is reached that it can provide useful, if often rough, estimates of the rate of primary production. The experimental estimates were calculated both for the experimental periods, and for longer daily periods, using some general equations previously proposed. The calculations from diurnal changes and from experimental data are in agreement con­cerning the order of magnitude of production, but close conformity was obtained for only one series of observations. The areal values of production estimated from diurnal changes lay in a limited range of 4 to 11 g oxygen (equivalent to approximately 1⋅5 to 4 g carbon) m -2 day -1 , despite considerable variation in individual factors such as population density and under­water light penetration. These values are similar to other estimates for phytoplankton in very productive waters.

Seaweeds and the Exxon Valdez Oil Spill

1993 ◽  
Vol 1993 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Michael S. Stekoll ◽  
Lawrence Deysher ◽  
Thomas A. Dean
Keyword(s):  
Oil Spill ◽  
Intertidal Zone ◽  
High Tide ◽  
Algal Species ◽  
Percent Cover ◽  
Prince William Sound ◽  
Cook Inlet ◽  
Exxon Valdez ◽  
Exxon Valdez Oil Spill ◽  
Upper Intertidal

ABSTRACT A three-year study, initiated in 1989, has evaluated the response of subtidal and intertidal seaweed communities to the Exxon Valdez oil spill and subsequent cleanup activities. The project was part of the coastal habitat injury assessment research sanctioned under the natural resource damage assessment program. A stratified random design was used to select oiled sites for the study. Paired control (unoiled) sites were then matched to the oiled sites. The most consistent effect found in subtidal populations in Prince William Sound was the higher relative abundance of small-size classes of kelps at the oiled sites, indicating the prior disappearance of larger plants. This disappearance was possibly caused by activities associated with the cleanup operations. Intertidal populations of algae were affected by the spill and cleanup in all three major areas studied: Prince William Sound, Cook Inlet-Kenai, and Kodiak-Alaskan Peninsula. The most obvious effect was a significant removal of the dominant intertidal plant Fucus gardneri from the mid and upper intertidal zones. The limited dispersal of this plant combined with the relatively harsh conditions of the upper intertidal will cause a slow recovery of the upper intertidal zone in the affected areas. Effects of the spill extended to other algal species. Species such as Cladophora, Myelophycus, Odonthalia, Palmaria, and Polysiphonia showed decreases in their percent cover at oiled sites. Only Gloiopeltis populations appeared to increase in percent cover in oiled areas. In both the Cook Inlet-Kenai and the Kodiak-Alaskan Peninsula areas Fucus populations appeared to be enhanced in the lower intertidal zone—between 2 and 3 meters below the high-tide mark—in 1991.

Ages of Subsurface Stratigraphic Intervals in the Quaternary of Enewetak Atoll, Marshall Islands

1985 ◽  
Vol 23 (1) ◽  
pp. 54-61 ◽  
Author(s):  
B. J. Szabo ◽  
J. I. Tracey ◽  
E. R. Goter
Keyword(s):  
Oxygen Isotope ◽  
Marshall Islands ◽  
Coral Growth ◽  
Radiocarbon Dates ◽  
Oxygen Isotope Stage ◽  
Uranium Series ◽  
The Third ◽  
Activity Ratios ◽  
Enewetak Atoll ◽  
Reef Platform

Drill cores of Enewetak Atoll, Marshall Islands, reveal six stratigraphic intervals, numbered in downward sequence, which represent vertical coral growth during Quaternary interglaciations. Radiocarbon dates indicate that the Holocene sea transgressed the emergent reef platform by about 8000 yr B.P. The reef grew rapidly upward (about 5 to 10 mm/yr) until about 6500 yr B.P. Afterward vertical growth slowed to about 0.5 mm/yr, then lateral development became dominant during the last several thousand years. The second interval is dated at 131,000 ± 3000 yr B.P. by uranium series. This unit correlates with oxygen-isotope substage 5e and with terrace VIIa of Huon Peninsula, New Guinea, and of Main Reef-2 terrace at Atauro Island. The third interval is not dated because corals were recrystallized and it is tentatively correlated with either oxygen-isotope stages 7 or 9. The age of the fourth interval is estimated at 454,000 ± 100,000 yr B.P. from measured 234U238U activity ratios. This unit is correlated with either oxygen-isotope stage 9, 11, or 13.

Tree-climbing behaviour of Cerithidea decollata, a western Indian Ocean mangrove gastropod (Mollusca: Potamididae)

2006 ◽  
Vol 86 (6) ◽  
pp. 1429-1436 ◽  
Author(s):  
Marco Vannini ◽  
Rocco Rorandelli ◽  
Outi Lähteenoja ◽  
Elisha Mrabu ◽  
Sara Fratini
Keyword(s):  
Indian Ocean ◽  
Neap Tide ◽  
High Tide ◽  
Spring Tide ◽  
Western Indian Ocean ◽  
High Water ◽  
Avicennia Marina ◽  
Single Individual ◽  
Night Time ◽  
Mangrove Tree

The behaviour of Cerithidea decollata, a common western Indian Ocean mangrove tree climbing gastropod, was studied in Mida Creek, Kenya. At the study site, this snail mainly lived in Avicennia marina dominated areas, i.e. in the mangrove belt between high water spring tide and high water neap tide levels. Not a single individual was found on the less common mangrove tree Lumnitzera racemosa, living just above the A. marina level (together with terrestrial grass), and was very rarely recorded on the common Rhizophora mucronata, bordering the seaward side of the A. marina belt. No significant gradient of C. decollata density was found within the whole 150–200 m wide belt. The majority of C. decollata rested on tree trunks during high tide, creeping on the mud flat below the tree for part of low tide, and returning on the trunks well before being reached by the water. This migratory pattern was more evident at spring than at neap tide, at day than at night time and it was strongly influenced by the shore level of the mangrove zone in which animals resided. While C. decollata from lower shore levels neatly massively migrated twice a day, individuals from upper levels showed a more continuous and irregular activity, sometimes crawling on the mud even at high water of spring tide, when they experience just a few centimetres of water for no more than one to two hours.

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