Current velocity and nutrient level effects on the morphology of Phormidium retzii (Cyanobacteria) in artificial stream mesocosms

2004 ◽  
Vol 113 ◽  
pp. 87-99 ◽  
Author(s):  
Dale A. Casamatta ◽  
Morgan L. Vis
Keyword(s):  
Current Velocity ◽  
Nutrient Level ◽  
Artificial Stream ◽  
Stream Mesocosms

The influence of current velocity and substrate on the distribution and drift of two species of mayflies (Ephemeroptera)

1977 ◽  
Vol 55 (12) ◽  
pp. 1970-1977 ◽  
Author(s):  
Lynda D. Corkum ◽  
P. J. Pointing ◽  
Jan J. H. Ciborowski
Keyword(s):  
Current Velocity ◽  
Substrate Type ◽  
Artificial Stream ◽  
Inorganic Substrates ◽  
Significant Mechanism

The effects of substrate type and current velocity on the distribution and drift of Baetis vagans McDunnough and Paraleptophlebia mollis (Eaton) were examined in an artificial stream. Of those B. vagans (swimming nymphs) remaining on the substrates, most were retrieved from branches while few were found in inorganic substrates. In all cases, numbers of B. vagans remaining on the substrates increased as current velocities increased. Paraleptophlebia mollis (crawling nymphs) were most frequently associated with gravel (11.2–16 mm diameter), whereas branches were of less importance.At 50 cm/s and during darkness, the proportion of P. mollis drifting from a 'least preferred' substrate was comparable with that of B. vagans. At lower velocities or in light, B. vagans drifted more frequently than did P. mollis, regardless of substrate type. For both species, drift was a significant mechanism in dispersal of individuals from unfavourable areas.

Episodic loadings of phosphorus influence growth and composition of benthic algae communities in artificial stream mesocosms

2020 ◽  
Vol 185 ◽  
pp. 116139
Author(s):  
Nolan J.T. Pearce ◽  
Kathryn E. Thomas ◽  
Isabelle Lavoie ◽  
Patricia A. Chambers ◽  
Adam G. Yates
Keyword(s):  
Benthic Algae ◽  
Artificial Stream ◽  
Stream Mesocosms

Assessment of micro and macro nutrients in poultry feeds available in Dhaka city, Bangladesh.

2017 ◽  
Vol 1 ◽  
pp. 264
Author(s):  
Md Didarul Islam ◽  
Ashiqur Rahaman ◽  
Fahmida Jannat
Keyword(s):  
Heavy Metals ◽  
Adverse Effect ◽  
The Other ◽  
Nutrient Level ◽  
Dhaka City ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Low Concentration ◽  
Feed Formulation ◽  
Macro Nutrients

This study was based on to determine the concentration of macro and micro nutrients as well as toxic and nontoxic heavy metals present in the chicken feed available in Dhaka city of Bangladesh. All macro nutrients, if present in the feed at high concentration have some adverse effect, at the same time if this nutrient present in the feed at low concentration this have some adverse effect too. So that this nutrient level should be maintained at a marginal level. On the other side toxic heavy metals if present in the feed at very low concentration those can contaminate the total environment of the ecosystem. In this study six brand samples (starter, grower, finisher and layer) which was collected from different renowned chicken feed formulation industry in Bangladesh. Those samples were prepared for analysis by wet ashing and then metals were determined by Atomic Absorption Spectroscopy. It was found that 27.7 to 68.4, 57.3 to 121.9, 0.21 to 4.1, 0.32 to 2.1, 0.11 to 1.58, 0.28 to 2.11 and 0.28 to 1.78 for zinc, iron, copper, mercury, cadmium, nickel and cobalt respectively. It was found that essential macro and micro nutrients were present in the feed in low concentration on the other side mercury was present in high concentration in the feed samples.

Use of an artificial stream to monitor avoidance behavior of larval sea lamprey in response to TFM and niclosamide

2021 ◽  
Author(s):  
Nicholas Schloesser ◽  
Mike Boogaard ◽  
Todd Johnson ◽  
Courtney Kirkeeng ◽  
Justin Schueller ◽  
...  
Keyword(s):  
Avoidance Behavior ◽  
Sea Lamprey ◽  
Artificial Stream

scholarly journals Combined Effects of Summer Water Temperature and Current Velocity on the Distribution of a Cold-Water-Adapted Sculpin (Cottus nozawae)

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 975
Author(s):  
Kaiji Suzuki ◽  
Nobuo Ishiyama ◽  
Itsuro Koizumi ◽  
Futoshi Nakamura
Keyword(s):  
Water Temperature ◽  
Climate Warming ◽  
Current Velocity ◽  
Cold Water ◽  
Environmental Gradients ◽  
Combined Effect ◽  
Influential Factor ◽  
Combined Effects ◽  
River Catchment ◽  
Water Abstraction

Clarifying the combined effects of water temperature and other environmental factors on the species distributions of cold-water fishes is the first step toward obtaining a better understanding of the complex impacts of climate warming on these species. In the present study, we examined the abundance and occurrence of the fluvial sculpin, Cottus nozawae, in response to water temperature along environmental gradients in northern Japan. The abundance survey was conducted in the Sorachi River catchment with two-pass electrofishing with a backpack electrofisher. For the occurrence survey, we carried out one-pass electrofishing in the Sorachi, Chitose, and Tokachi River catchments. Fish sampling was conducted once from July to August 2018 in the Sorachi River catchment, from May to June 2011 in the Chitose River catchment, and from July to September 2012 in the Tokachi River catchment. Generalized linear mixed models (GLMMs) and generalized linear models (GLMs) were used for the abundance and occurrence analyses, respectively. We found that the mean summer water temperature was the most influential factor on the distribution of C. nozawae; the abundance and occurrence were both negatively affected by increased water temperatures. In the occurrence model, occurrence probabilities of 0.9 and 0.5 for C. nozawae corresponded to mean summer temperatures of 12.0 and 16.1 °C, respectively. Furthermore, we identified a combined effect of water temperature and current velocity on the abundance of C. nozawae. The increased mean summer water temperature had a stronger negative effect on C. nozawae abundance under gentle flow conditions. While the precise mechanisms of this combined effect could not be determined in this study, stressors associated with low current velocities may increase their vulnerability to higher water temperatures. Our findings indicate that flow disturbances caused by human activities such as excessive water abstraction may exacerbate the negative impacts of climate warming on populations of C. nozawae in the future.

The effect of nutrient level on plant structure and production in a wet grassland: a field study

Plant Ecology ◽  
2010 ◽  
Vol 212 (5) ◽  
pp. 809-819 ◽  
Author(s):  
Miroslava Káplová ◽  
Keith R. Edwards ◽  
Jan Květ
Keyword(s):  
Field Study ◽  
Nutrient Level ◽  
Plant Structure ◽  
Wet Grassland

Wave action on currents with vorticity

1999 ◽  
Vol 386 ◽  
pp. 329-344 ◽  
Author(s):  
BENJAMIN S. WHITE
Keyword(s):  
Phase Shift ◽  
Deep Water ◽  
Current Velocity ◽  
Wave Action ◽  
Ray Theory ◽  
Wkb Method ◽  
Interaction Of Waves ◽  
New Equation ◽  
Spatially Varying

The interaction of waves on deep water with spatially varying currents may be described by a ray theory, with the wave amplitudes determined by the principle of conservation of wave action (CWA). However, all previous deep water derivations of CWA are restricted to the case of an irrotational current. In this paper, both the ray theory and CWA are derived by a WKB method without the assumption of irrotationality. Also derived is a new equation for a spatially varying phase shift which is not predicted by the usual ray theory, and which, in general, displaces the positions of the wave crests by a distance on the order of a wavelength. This phase shift, which is caused by variations of the current velocity with depth, vanishes in the irrotational case, and so is in accord with the irrotational theory.

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