Modifications in Sampling Procedures as Applied to Studies on the Bacteria and Tubificid Oligochaetes Inhabiting Aquatic Sediments

1969 ◽  
Vol 26 (10) ◽  
pp. 2581-2593 ◽  
Author(s):  
R. O. Brinkhurst ◽  
K. E. Chua ◽  
E. Batoosingh
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Benthic Invertebrates ◽  
Standing Stock ◽  
Basic Design ◽  
Size Limitation ◽  
Multiple Unit ◽  
Bottom Sampling ◽  
Sampling Procedures ◽  
The Vertical Distribution

The KB corer has many advantages over other bottom-sampling devices including some other coring tubes. It may be used to obtain reliable estimates of the standing stock of benthic invertebrates inhabiting soft sediments and of their spatial distribution in lakes and rivers. It may also be used for studies of the vertical distribution of animals and bacteria, and could be used for a wide variety of studies on sediments. Multiple-unit versions have been built and operated, thus overcoming the size limitation imposed by the basic design. This paper communicates some results obtained using this sampler.

A Modified Freeze-Core Technique to Quantify the Depth Distribution of Fauna in Stony Streambeds

1983 ◽  
Vol 40 (5) ◽  
pp. 637-643 ◽  
Author(s):  
C. W. Pugsley ◽  
H. B. N. Hynes
Keyword(s):  
Vertical Distribution ◽  
Liquid Nitrogen ◽  
Benthic Invertebrates ◽  
Depth Distribution ◽  
Sampling Methods ◽  
Freezing Front ◽  
Southern Ontario ◽  
Freeze Core ◽  
Order Of Magnitude ◽  
The Vertical Distribution

A freeze-coring device using liquid nitrogen is described, which enables one person to take a columnar core, extending from the surface to at least 50 cm below a stony streambed. An experiment to validate the technique showed that animals did not flee from the advance of the freezing-front. Using frozen streambed cores, the vertical distribution of benthic invertebrates of two streams in southern Ontario was investigated. In contrast to previous estimates,~70% of the fauna was found in the top 10 cm of the streambed, and invertebrate densities were often lower by an order of magnitude. These differences are attributed to problems of quantifying previous sampling methods.

A method for retrieving the spatial distribution of trace gases using measurements of three ground-based MAX-DOAS instruments

2020 ◽  
Author(s):  
Michael Revesz ◽  
Stefan F. Schreier ◽  
Philipp Weihs ◽  
Tim Bösch ◽  
Kezia Lange ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Trace Gases ◽  
Trace Gas ◽  
Wind Condition ◽  
Vertical Profiles ◽  
Open Issue ◽  
Using Data ◽  
Set Up ◽  
The Vertical Distribution

<p>Within the project VINDOBONA (VIenna horizontal aNd vertical Distribution OBservations Of Nitrogen dioxide and Aerosols), a method was developed to retrieve the spatial distribution of trace gases using data from three ground based MAX-DOAS instruments and was applied on the example of NO<sub>2</sub>. At three different locations in Vienna (Austria) MAX-DOAS instruments were installed performing measurements in the visible and UV spectral range. Currently, each instrument is set up to determine the column densities in different azimuthal directions and low elevation angles within approximately a horizontal plane. The different lines of sight of the three instruments intersect horizontally and can be used to estimate the horizontal spatial distribution of trace gases. With the knowledge of vertical profiles, even the vertical distribution can be estimated using this method. </p><p>The intersections of the different lines of sight define segments along the slant columns for which the mass concentrations can be estimated. Knowledge about the vertical profiles for a chosen trace gas can be used to correct the retrieved trace gas concentration to specific altitudes above ground. Such corrections are also required since the three instruments were set up at different heights above ground, at different altitudes relative to sea level and with different elevation angles of the lowest viewing direction. One open issue for the retrieval process is the terrain in Vienna in combination with the prevailing wind condition that impacts the horizontal and vertical trace gas distribution and make the retrieval challenging. </p>

scholarly journals Seasonal variation of the crustacean fauna in the belowground and aboveground strata in a Halodule wrightii meadow of northeastern Brazil

2017 ◽  
Vol 107 (0) ◽  
Author(s):  
Kcrishna V. S. Barros ◽  
Jesser F. Souza-Filho ◽  
Ricardo J. C. Paiva ◽  
Catarina L. Araújo-Silva ◽  
Alexandre O. Almeida ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Seasonal Variation ◽  
Vertical Distribution ◽  
The Other ◽  
Northeastern Brazil ◽  
Halodule Wrightii ◽  
The Vertical Distribution

ABSTRACT The different microhabitats provided by seagrasses and the habit of the species determinate the vertical distribution of crustaceans. This study verified the influence of the seasonality on the spatial distribution of the crustacean community associated with a Halodule wrightii meadow. From April 2006 to July 2007, we performed fifteen samplings in Goiabeiras Beach, Ceará State, each with five sectioned replicates in belowground and aboveground. Cumaceans and the amphipod Hyale media (Dana, 1853) had a higher frequency, density, and dominance than the other taxa, in both strata. The community exhibited gradual changes along the study, in both the belowground and aboveground strata, but the seagrass structure was not sufficient to explain the vertical distribution of the crustacean fauna along the time.

Evaluation of a high resolution regional atmospheric chemistry model using MAX-DOAS and in situ NO2 measurements

2021 ◽  
Author(s):  
Vinod Kumar ◽  
Julia Remmers ◽  
Steffen Beirle ◽  
Astrid Kerkweg ◽  
Jos Lelieveld ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Vertical Distribution ◽  
Atmospheric Chemistry ◽  
Pearson Correlation ◽  
Surface Concentration ◽  
Ozone Production ◽  
Vertical Column ◽  
The Impact ◽  
The Vertical Distribution

<p>Regional atmospheric chemistry models are adopted for simulating concentrations of atmospheric components at high resolution and quantifying the impact of localized emissions (e.g. industrial and urban clusters) on the non-linear chemical processes, e.g. ozone production. However, their evaluation is challenging due to the limited availability of high spatiotemporally resolved reference datasets. For the same reason, the vertical distribution of pollutants simulated by the model is especially arduous to assess.</p><p>Here, we present regional atmospheric chemistry model studies with spatial resolution up to 2.2 × 2.2 km<sup>2</sup> focused around Germany for May 2018 using the MECO(n) model system. Using a network of surface concentration measurements at background, near traffic and industrial locations, we evaluate the spatial distribution of NO<sub>2</sub> simulated by the model. The highly resolved model together with a comparable resolution and up-to-date input emissions inventory, was found to perform best in reproducing the spatial distribution of NO<sub>2</sub> surface volume mixing ratios (VMRs). We propose a computationally efficient approach to account for the diurnal and day of the week variability of input anthropogenic emissions (e.g. from road transport), which proved to be crucial for resolving the temporal variability of NO<sub>2</sub> surface VMRs.</p><p>The simulated NO<sub>2</sub> tropospheric vertical column densities were evaluated by employing the measurements of a 4-azimuth MAX-DOAS instrument in Mainz. Generally, such comparisons do not account for the spatial sensitivity volume of the MAX-DOAS measurements, the change of sensitivity within this volume and the spatial heterogeneity of NO<sub>2</sub>. We therefore apply a consistent approach of comparison of the differential slant column densities (dSCDs), which overcomes these limitations. Moreover, the dSCDs are obtained for several elevation and azimuth angles, which are characterized by distinctive sensitivity for different vertical levels within the boundary layer and different horizontal representativeness. Hence, also an evaluation of the model in simulating the vertical distribution of NO<sub>2</sub> can be performed with this approach using continuous MAX-DOAS measurements spanning long time periods. We found that the model performs well with respect to the measured dSCDs at low elevation angles (< 8°) with an overall bias between +14 and -9%, and Pearson correlation coefficients between 0.5 and 0.8 for the different azimuth viewing directions.</p>

Study on the Vertical Distribution of Cr in Jiaozhou Bay

2014 ◽  
Vol 675-677 ◽  
pp. 329-331 ◽  
Author(s):  
Dong Fang Yang ◽  
Feng You Wang ◽  
Hua Zhong He ◽  
Cheng Yang ◽  
Si Xi Zhu
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Pollution Control ◽  
Environmental Remediation ◽  
Water Exchange ◽  
Jiaozhou Bay ◽  
Point Of View ◽  
Transfer Processes ◽  
Gravity Settling ◽  
The Vertical Distribution

Based on investigation dada on Cr in 1982 in Jiaozhou Bay, this paper analyzed the seasonal and spatial distribution of Cr, and revealed the transfer process of Cr. Results showed that horizontal diffusion and vertical sedimentation were major transfer processes of Cr, which were mainly determined by water exchange and gravity settling. These findings were essential to pollution control and environmental remediation in Jiaozhou Bay. From the point of view of pollution control, reducing the discharge of Cr from the sources was the major countermeasure.

Vertical distribution of Benthic Invertebrates in the Bed of the Thomson River, Victoria

1988 ◽  
Vol 39 (6) ◽  
pp. 775 ◽  
Author(s):  
R Marchant
Keyword(s):  
Vertical Distribution ◽  
Benthic Invertebrates ◽  
Benthic Fauna ◽  
Late Summer ◽  
Sample Surface ◽  
Depth Range ◽  
The Vertical Distribution ◽  
Surber Sampler

The vertical distribution of the benthic fauna was studied at three sites on the Thomson River using a freeze-corer. Samples were taken over two years in early and late summer. At each site an average of 72 to 84% of the fauna was found in the 0-10 cm zone of the riverbed, 10-20% in the 10-20 cm zone and 6-8% in the 20-30 cm zone; flooding at one site was followed by an increase in the depth to which the fauna penetrated. Surface percentage abundances were probably underestimated because of the inability of the corer to sample surface rocks and their fauna consistently and because the coring operation disturbs the surface fauna to some extent before it can be frozen. Nevertheless, the results indicate that in the Thomson River the majority of the fauna is within the depth range (0-10 cm) of a Surber sampler.

scholarly journals ANALYSIS OF THE THERMOHALINE STRUCTURE IN THE ACTIVE LAYER OF THE MARINE ENVIRONMENT ACCORDING TO THE CALCULATED HYDROPHYSICAL CHARACTERISTICS BASED ON REMOTE MEASUREMENTS (ON THE EXAMPLE OF THE BLACK SEA)

2021 ◽  
Author(s):  
Andrii Sryberko ◽  
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Water Temperature ◽  
Active Layer ◽  
Black Sea ◽  
Marine Environment ◽  
The State ◽  
The Black Sea ◽  
Thermohaline Structure ◽  
The Vertical Distribution

Today, one of the priority scientific directions in marine sciences is the study of the spatial distribution of hydrophysical characteristics in the marine environment by remote measurements methods. To studying the spatio-temporal variability of water temperature and salinity in the active layer of the marine environment, it is necessary to use the data of their vertical and spatial distribution. Today there does not exist an easy way to get a in situ data for the analysis of the thermohaline structure in the marine environment. Indirect definitions of the vertical and spatial distribution of water temperature and salinity through the development of various methods for the calculation of thermohaline characteristics are used to date. Main purpose of this work is to study the thermohaline structure in the active layer of the Black Sea according to the calculated hydrophysical characteristics based on satellite and hydroacoustic data. The study of the vertical distribution of water temperature and salinity in the Black Sea was carried out in the deep-water part sea at standard levels (0, 10, 20, 25, 30, 50 meters) in the spring –autumn period. This area of research is represented by the highest number of measurements and is included in the Main Black Sea current zone. The calculations of thermohaline characteristics in the marine environment are based on the original methods of calculating the vertical distribution of water temperature, sound speed and salinity of water by satellite and hydroacoustic data. These methods were developed in the State Institute “Hydroacoustic Branch of Institute of Geophysics by S.I. Subbotin name of the National Academy of Sciences of Ukraine”. Mathematical and physical-statistical methods of calculation were used in the developed methods. For the efficiency of calculations an Automated Program Complex (APC) for calculating the vertical distribution of temperature and salinity fields in the marine environment by satellite and hydroacoustic data has been developed and tested on the example of the Black Sea. The initial data for the calculations using the APC are only daily satellite data of the sea surface temperature. Based on the results of calculations of the APC, maps of the vertical distribution of temperature and salinity of water on zonal and meridional sections in the Black Sea in the period of spring – autumn 2018 were developed. Analysis of the results of calculations of the vertical distribution of thermohaline characteristics made it possible to identify the main features in these distributions. The features of the spatial-temporal distribution of thermohaline parameters have been analysed. The confirmation of the state of the thermohaline regime inherent in the Black Sea in the warm season was obtained. The results of calculations of the vertical distribution of thermohaline characteristics in the Black Sea deep-water area on the basis of satellite and hydroacoustic data using the developed methods showed the possibility and expediency of their application in the layer 0-50 meters in the period May-October for a detailed analysis of the state of the thermohaline structure. The developed methods and principles of building an the APC for calculation of vertical distribution of temperature and salinity fields of water according to satellite and hydroacoustic data can be applied for analysis and monitoring of others water area of the World Ocean taking into account their hydrological conditions.

Introduction to the palaeontology of the Dinantian of Foulden, Berwickshire, Scotland

1985 ◽  
Vol 76 (1) ◽  
pp. 1-6 ◽  
Author(s):  
S. P. Wood ◽  
W. D. Ian Rolfe
Keyword(s):  
Spatial Distribution ◽  
Vertical Distribution ◽  
Bivalve Mollusc ◽  
Marine Bivalve ◽  
Layer By Layer ◽  
Scientific Interest ◽  
Layer Analysis ◽  
Special Scientific ◽  
Shell Bed ◽  
The Vertical Distribution

ABSTRACTThe Foulden Site of Special Scientific Interest is one of the few Cementstone Group localities that yields significant fauna and flora. Excavations in 1980 and 1981 removed a 1·3 m2 slab of the Fish Bed for laboratory study of the vertical and spatial distribution of the biota. Layer by layer analysis revealed an almost mutually exclusive relationship between the vertical distribution of the palaeoniscoid fishes and malacostracan crustaceans, as well as a horizon crowded with juvenile acanthodians. Elongate elements of this biota showed slight preferred orientations at that prolific horizon. Some 27 m of strata including the Fish Bed, Plant Bed and Shell Bed are recorded in detail, and their biota noted. Interim results of work on the main groups collected are summarised in associated papers in this part of Transactions. Brief reports are given here on the euryhaline marine bivalve mollusc Modiolus latus (Portlock), a rare durophagous bradyodont shark tooth and an Eogyrinus-like amphibian scute.

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