Modeling Light Loss Versus UV-B Increase for Organisms Which Control Their Vertical Position in the Water Column

1982 ◽  
pp. 539-542 ◽  
Author(s):  
John Calkins
Keyword(s):  
Water Column ◽  
Vertical Position ◽  
Light Loss

Vertical Distribution of Northern Shrimp (Pandalus borealis) Larvae in the Gulf of St Lawrence; Implications for Trophic Interactions and Transport

1994 ◽  
Vol 51 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Patrick Ouellet ◽  
Denis Lefaivre
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Suspended Particle ◽  
Stage I ◽  
Vertical Position ◽  
Pandalus Borealis ◽  
Northern Shrimp ◽  
Residual Transport ◽  
Larval Emergence ◽  
The Vertical Distribution

In the northwestern Gulf of St. Lawrence in spring 1987 and 1988, stage I and II northern shrimp (Pandalus borealis) larvae were concentrated in the upper (<30 m) layers above the permanent pycnocline and coincident with subsurface chlorophyll a and suspended particle concentration maxima; this was above other macrozooplankton taxa in the daytime. Shrimp larvae maintained their vertical position relative to the maximum density gradient in the water column in daytime but moved towards the surface at night. Estimation of larval residual transport (~66 km) during the first developmental stage (12 d) corresponded to the horizontal scale of patches of stage I shrimp larvae in the northwest sector of the Gulf. The result is consistent with the suggestion of localized and short-duration larval emergence in the sector. The direction of mass transport and current speed were similar throughout the upper layers of the water column; consequently, the direction and magnitude of larval shrimp transport were not dependent on their vertical position. We suggest that the vertical distribution maintained by shrimp larvae is a mechanism to ensure maximum food availability and to optimize development time in the stratified water of the northwestern Gulf of St. Lawrence.

scholarly journals Daily dynamics of vertical distribution and amount of sturgeons in riverbed depression in summer-autumn period

2019 ◽  
Vol 2019 (4) ◽  
pp. 55-69
Author(s):  
Andrey Stepanovich Aldokhin ◽  
Andrey Aleksandrovich Chemagin
Keyword(s):  
Water Column ◽  
Vertical Migration ◽  
Water Area ◽  
Fish Distribution ◽  
Vertical Position ◽  
Near Surface ◽  
Level Regime ◽  
Total Fish ◽  
Irtysh River ◽  
Riverbed Depression

The article presents the results of studying the fish distribution in the water column of the riverbed depression using remote echometric sounding with a software-hardware acoustic system with a vertical view. The study was conducted in the lower reaches of the Irtysh River. In the appointed period (July-October) under a decrease in the level regime and water temperature the increasing density of fish in the water area of the riverbed depression is explained by fish gathering in the period preceding wintering. The share of sturgeons varied from 5.46 to 10.28% of the total fish density, the indicators of which were in the range 1.70-5.05 thousand sp/ha in the daytime, 2.78-6.77 thousand sp/ha in the night. There has been stated the daily vertical migration of sturgeons, which is more uniform throughout the water column in the night, including the near-surface and near-bottom water horizons. In the dark near-surface water horizons are most intensively explored by large fish (25-30, 30-35, > 35 cm). The trigger of the daily vertical migration of sturgeons is supposed to be the light brightness, despite the poor eyesight of the fish under study, i.e. changing vertical position of sturgeons occurs due to endogenous circadian rhythms, as in many hydrobionts. The recorded features of sturgeon distribution because of preference of the direction and intensity of various factors can contribute to the optimization of bioenergy losses in hard turbulent conditions of riverbed depressions.

scholarly journals I. Experiments on the friction between water and air

1876 ◽  
Vol 24 (164-170) ◽  
pp. 441-442
Keyword(s):  
Water Column ◽  
Glass Tube ◽  
Soap Film ◽  
Feeding Tube ◽  
Vertical Position ◽  
Internal Diameter ◽  
Mutual Friction

The method adopted for estimating the mutual friction of water and air consisted in connecting a glass tube of 8 centims. in length and 0·72 internal diameter with the pipes which supply Vienna with water at a pressure of four atmospheres. Arrangements for securing a vertical position for the tube ensure a perfectly continuous jet, devoid of any broken surface; and a glass tube surrounding this jet, with its axis coinciding with that of the jet, acts as an aspirator into and along which air is drawn through a lateral feeding-tube. The amount of this indrawn air corresponding to the fall of a given amount of water was determined by observing the rate at which a film of soap was borne along the feeding-tube; and the velocity of the water causing the indraught was calculated from the diameter of the water column and the quantity of water discharged along it in a given time; but after having once determined the form of the slightly conical water column, the amount of water discharged was the only datum required for the calculation. The influence of a greater or less section of the air feeding-tube on the volume of the aspirated air was carefully determined, while also the absence of any appreciable retardation due to the soap film was established.

scholarly journals Demonstration of a Multiple Drift Net for Aquatic Organisms

2021 ◽  
Vol 79 (1) ◽  
pp. 25-32
Author(s):  
Michael D. Porter ◽  
Seth Kennedy ◽  
Juddson Sechrist
Keyword(s):  
Vertical Distribution ◽  
Water Column ◽  
Aquatic Organisms ◽  
Transport Processes ◽  
Vertical Position ◽  
Flow Conditions ◽  
Fish Eggs ◽  
Broadcast Spawning ◽  
Modeling Transport ◽  
The Vertical Distribution

Abstract The distribution of drifting semi-buoyant fish eggs within a river is useful for understanding the ecology of pelagic-broadcast spawning fish. The vertical position of semi-buoyant eggs in the water column is an important parameter describing transport processes for these species. We designed a multiple drift net (five rectangular nets attached to a frame) to vertically divide the water column into stacked horizontal layers to sample drifting semi-buoyant particles. We deployed the multiple drift net gear beside Moore egg collectors in a wadeable channel to sample the vertical distribution of semi-buoyant polyacrylamide gel beads as surrogates for fish eggs in the water column. The vertical distribution of beads was predominantly found in the deeper nets of the multiple drift net gear while the surface nets and Moore egg collectors had fewer beads which is similar to the results in other studies of pelagic-broadcast spawning fish. The multiple drift net gear is a tool that demonstrates the capability to sample the water column under variable flow conditions (depth, velocity and turbulence) for field data on the vertical distribution of drifting eggs (or surrogates). These empirical data can quantify drift patterns of eggs for modeling transport and retention in pelagic-broadcast spawning species.

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

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