Predicting night time dissolved oxygen loss in prawn ponds of Hawaii: Part I. Evaluation of traditional methods

The Whole Pond Respiration–Diffusion (WPRD) model was evaluated for brackish-water ponds. The WPRD model accurately describes the nighttime decline of dissolved oxygen concentration (DO) in both freshwater and brackish-water ponds. DO, water temperature, and wind speed were monitored overnight in marine shrimp (Penaeus vannamei and P. monodon) ponds at Amorient Aquafarm Inc. (Kahuku, Oahu) and at the Mariculture Research and Training Center (Hakipuu, Oahu) during July through December 1986. The model performed well for calm nights (wind speed between 1 and 2 m∙s−1) and for relatively windy nights (wind speed greater than 7 m∙s−1). Diffusion of oxygen into the ponds, particularly at Amorient, was important in determining the nighttime DO decline. The model has yielded accurate predictions of dawn DO for a variety of aquaculture ponds and meteorological conditions.

Download Full-text

A Colorimetric Method for Assaying Dissolved Oxygen Loss from Container-Grown Rice Roots

Agronomy Journal ◽

10.2134/agronj1994.00021962008600030005x ◽

1907 ◽

Vol 86 (3) ◽

pp. 483-487 ◽

Cited By ~ 48

Author(s):

H. K. Kludze ◽

R. D. DeLaune ◽

W. H. Patrick

Keyword(s):

Dissolved Oxygen ◽

Colorimetric Method ◽

Oxygen Loss ◽

Rice Roots

Download Full-text

Unusual vertical distribution of zooplankton and fish in the pelagic zone of Lake Sevan during summer stratification

Ecosystem Transformation ◽

10.23859/estr-210312 ◽

2021 ◽

Vol 4 (3) ◽

pp. 27-41

Author(s):

Mikhail I. Malin ◽

Svetlana M. Zhdanova ◽

Dmitriy B. Kosolapov ◽

Inga P. Malina ◽

Natalya G. Kosolapova ◽

...

Keyword(s):

Dissolved Oxygen ◽

Vertical Distribution ◽

Water Temperature ◽

Lower Boundary ◽

Fish Population ◽

Coregonus Lavaretus ◽

Zooplankton Abundance ◽

Night Time ◽

Lake Sevan ◽

Oxygen Concentrations

Previous studies in Lake Sevan during summer stratification have shown that the highest zooplankton abundance and biomass was found at the lower boundary of the epilimnion. At the same time, whitefish (Coregonus lavaretus), being main planktivorous species in the lake, preferred the hypolimnion, but was leaving this layer if dissolved oxygen concentrations decreased to 1–5 mg/L. The study was conducted in Bolshoy Sevan (the southern part of Lake Sevan) on July 29–30, 2019. The vertical profiles of water temperature and dissolved oxygen concentration, as well as distribution of major taxonomic groups of aquatic organisms were assessed four times a day: in the dark (night time), in the light (day time), and in twilight (morning and evening). Fish population density was assessed using a “Simrad EK80” echosounder. Vertical distribution of zooplankton and fish observed within the study period did not correspond to that described earlier. Maximal zooplankton biomass during the study was recorded in the hypolimnion, and minimal biomass, in the epilimnion. Most of fish (89–100%) located in the metalimnion. At night, about 10% of the fish population descended to the hypolimnion, despite the low dissolved oxygen concentrations found there (3.0–3.1 mg/L). At dawn, about 7% of the fish ascended to the epilimnion, reaching a 7-m depth, where the water temperature was 20.8 °C. The water temperature range preferred by most fish individuals varied during the observation period and did not correspond to previously reported ranges.

Download Full-text

Does differentversusequal daytime and night-time respiration matter for quantification of lake metabolism using diel dissolved oxygen cycles?

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2011042 ◽

2011 ◽

Vol 47 (3) ◽

pp. 251-257 ◽

Cited By ~ 5

Author(s):

Nusret Karakaya

Keyword(s):

Dissolved Oxygen ◽

Night Time ◽

Lake Metabolism

Download Full-text

Effects of Dissolved O2 and Fe Availability on Growth, Morphology, Aerenchyma Formation and Radial Oxygen Loss of Canna indica L. and Heliconia psittacorum L.f.

Chiang Mai University Journal of Natural Sciences ◽

10.12982/cmujns.2021.086 ◽

2021 ◽

Vol 20 (4) ◽

Author(s):

Tanapong Suriyakaew ◽

◽

Arunothai Jampeetong ◽

Keyword(s):

Plant Growth ◽

Dissolved Oxygen ◽

Ferrous Iron ◽

Radial Oxygen Loss ◽

Growth Morphology ◽

Aerenchyma Formation ◽

Root Porosity ◽

Oxygen Loss ◽

Canna Indica ◽

Hypoxic Conditions

Abstract In constructed wetlands (CWs), plants are usually affected by low O2 levels. Under such conditions, most soluble iron is reduced to ferrous (Fe2+) which is highly soluble, and toxic to plants as well. As a consequence of excessive ferrous iron with low O2 supply, plant growth is reduced, leading to declining nutrient removal efficiency. This study was conducted to determine the effects of different dissolved oxygen levels (normoxia and hypoxia) with Fe supplied on growth, morphology, and root anatomy of two wetland plants (Canna indica and Heliconia psittacorum). The plants were grown on a nutrient solution modified from Smart and Barko (1985) under normoxic and hypoxic conditions. All plants were grown in greenhouse conditions for 42 days. Plant growth rates and biomass accumulation were drastically reduced under hypoxia while leaf number was not affected. Under hypoxia, root diameter and root porosity also increased in C. indica, whereas H. psittacorum had greater aerenchyma formation. Moreover, C. indica showed adaptive traits to cope with hypoxia and Fe stress by increasing radial oxygen loss (ROL), releasing O2 to the rhizosphere to resist toxic effects of ferrous iron under hypoxia. In contrast, H. psittacorum had no ROL under hypoxia. Moreover, the plants showed leaf chlorosis, leaf roll, and root rotting. Hence, it is suggested that C. indica could have better performance than H. psittacorum to treat wastewater in CWs as this species can adapt to hypoxic conditions and releases O2 into rhizosphere which improves dissolved oxygen (DO) in the wastewater. Keywords: Aerenchyma, Dissolved oxygen, Iron, Root porosity, Wetland emergent plant

Download Full-text

Automated Elephant Entry Prevention for Human and Crop Protection

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.6.28451 ◽

2018 ◽

Vol 7 (4.6) ◽

pp. 401

Author(s):

Mahalakshmi K ◽

Kodanda Ramaiah G N ◽

Nandha Kishore ◽

K. Ramesh

Keyword(s):

Crop Protection ◽

Automated Detection ◽

Human Intervention ◽

Crop Raiding ◽

Night Time ◽

Traditional Methods ◽

Low Frequencies ◽

Offensive Behavior ◽

Electric Fencing

Farming in areas with elephants has been the norm in many parts of Asia for thousands of years. In particular, farmers have settled closer to areas where elephants are present and started growing crops. Elephant raids occur in the night time where people do not notice the presence of an elephant until it starts an oﬀensive behavior. Such raids damage the crops, harvest storages and homes in addition to causing deaths of humans. A multitude of traditional methods have been developed through the ages to reduce and prevent crop raiding by elephants like shouting, drum-beating, noise-making, use of fire crackers, electric fencing, lights and torches. Such activities may also indicate to elephants that their presence is detected, and that they have to contend with aggressive humans. In the proposed system, automated detection of the presence of elephant is done by analyzing the infrasonic sounds produced by elephants and they are prevented from entering into farms by propagating the offensive sounds in low frequencies without human intervention.

Download Full-text

Investigation of ultra-thin films of YBa2Cu3O7−δ grown on MgO

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173169 ◽

1990 ◽

Vol 48 (4) ◽

pp. 6-7

Author(s):

S.K. Streiffer ◽

C.B. Eom ◽

J.C. Bravman ◽

T.H. Geballet

Keyword(s):

Thin Films ◽

Room Temperature ◽

Deposition Process ◽

Nucleation And Growth ◽

Multilayer Structures ◽

Rf Power ◽

Oxygen Loss ◽

Transmission Electron ◽

Single Target ◽

Mtorr Argon

The study of very thin (<15 nm) YBa2Cu3O7−δ (YBCO) films is necessary both for investigating the nucleation and growth of films of this material and for achieving a better understanding of multilayer structures incorporating such thin YBCO regions. We have used transmission electron microscopy to examine ultra-thin films grown on MgO substrates by single-target, off-axis magnetron sputtering; details of the deposition process have been reported elsewhere. Briefly, polished MgO substrates were attached to a block placed at 90° to the sputtering target and heated to 650 °C. The sputtering was performed in 10 mtorr oxygen and 40 mtorr argon with an rf power of 125 watts. After deposition, the chamber was vented to 500 torr oxygen and allowed to cool to room temperature. Because of YBCO’s susceptibility to environmental degradation and oxygen loss, the technique of Xi, et al. was followed and a protective overlayer of amorphous YBCO was deposited on the just-grown films.

Download Full-text

One Size Fits All?

Methodology ◽

10.1027/1614-2241/a000044 ◽

2012 ◽

Vol 8 (1) ◽

pp. 23-38 ◽

Cited By ~ 1

Author(s):

Manuel C. Voelkle ◽

Patrick E. McKnight

Keyword(s):

Repeated Measures ◽

Structural Equation ◽

Type I Error ◽

Equation Modeling ◽

Type I ◽

Finite Sample ◽

Traditional Methods ◽

Repeated Measures Anova ◽

Special Cases ◽

Latent Curve

The use of latent curve models (LCMs) has increased almost exponentially during the last decade. Oftentimes, researchers regard LCM as a “new” method to analyze change with little attention paid to the fact that the technique was originally introduced as an “alternative to standard repeated measures ANOVA and first-order auto-regressive methods” (Meredith & Tisak, 1990, p. 107). In the first part of the paper, this close relationship is reviewed, and it is demonstrated how “traditional” methods, such as the repeated measures ANOVA, and MANOVA, can be formulated as LCMs. Given that latent curve modeling is essentially a large-sample technique, compared to “traditional” finite-sample approaches, the second part of the paper addresses the question to what degree the more flexible LCMs can actually replace some of the older tests by means of a Monte-Carlo simulation. In addition, a structural equation modeling alternative to Mauchly’s (1940) test of sphericity is explored. Although “traditional” methods may be expressed as special cases of more general LCMs, we found the equivalence holds only asymptotically. For practical purposes, however, no approach always outperformed the other alternatives in terms of power and type I error, so the best method to be used depends on the situation. We provide detailed recommendations of when to use which method.

Download Full-text