Whelk (Buccinum undatum) Movement and Its Implications for the Use of Tag–Recapture Methods for the Determination of Baited Trap Fishing Parameters

1991 ◽  
Vol 48 (5) ◽  
pp. 751-756 ◽  
Author(s):  
Bernard Sainte-Marie
Keyword(s):  
Experimental Conditions ◽  
Buccinum Undatum ◽  
North Shore ◽  
The North ◽  
In Situ Experiments ◽  
Two Parameters ◽  
Biased Estimates ◽  
Fishing Area

The tag–recapture method has been used to measure the field of attraction and the effective fishing area of a baited trap. The possibly conflicting experimental conditions required for the determination of these two parameters are, respectively, that tagged animals do not move and that they behave as undisturbed animals, prior to exposure to bait odour. Field observations and in situ experiments were conducted on the north shore of the Gulf of Saint Lawrence in 1988 and 1989 to compare behaviour of undisturbed and tagged whelks (Buccinum undatum). In the daytime, ~ 75% of undisturbed whelks were quiescent, being either buried and oriented randomly or static and oriented downstream, while the remainder moved across stream at 2–5 cm∙min−1. In contrast, > 97% of tagged whelks oriented in nonrandom directions and moved at equal or greater speeds, on average, 2.2–9.2 m from release points in less than 6 h. Because neither of the two basic conditions was met, tag–recapture experiments would produce biased estimates of baited trap fishing parameters.

New determinations of tides on the north-western Ross Ice Shelf

2020 ◽  
pp. 1-14
Author(s):  
Richard D. Ray ◽  
Kristine M. Larson ◽  
Bruce J. Haines
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
High Rate ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
The North ◽  
Global Positioning ◽  
North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

Quantitative determination of tip undercooling of faceted sea ice with in situ experiments

2021 ◽  
Author(s):  
Tongxin Zhang ◽  
Zhijun Wang ◽  
Lilin Wang ◽  
Junjie Li ◽  
Jincheng Wang
Keyword(s):  
Sea Ice ◽  
Quantitative Determination ◽  
In Situ Experiments

A Compact Microcontrolled Microfluidic System for Photometric Determination of Phosphate in Natural Water Samples

2015 ◽  
Vol 68 (7) ◽  
pp. 1108 ◽  
Author(s):  
Osmundo Dantas Pessoa-Neto ◽  
Tiago Almeida Silva ◽  
Vagner Bezerra dos Santos ◽  
Orlando Fatibello-Filho
Keyword(s):  
Light Emitting Diode ◽  
Flow Analysis ◽  
Photometric Determination ◽  
Microfluidic System ◽  
Experimental Conditions ◽  
Light Emitting ◽  
Experimental Parameters ◽  
Led Photometer

A compact environmentally friendly microcontrolled microfluidic device ideal for in situ phosphate determination was developed based on a microsystem based on low-temperature co-fired ceramics (LTCC) coupled to a light-emitting diode (LED)–photometer with a multicommutation flow analysis (MCFA) approach. The experimental parameters of the MCFA analyzer were optimized by chemometric studies. Under the best experimental conditions, limits of detection and quantification of 0.02 mg P L–1 and 0.07 mg P L–1, respectively, and a sampling frequency of 67 h–1 were estimated. Moreover, a low sample consumption of only 60 μL per determination was the other advantage that fully meets the requirements of sustainable research and green chemistry purposes.

In-situ investigation of alkalinity - denitrification coupling in the sediment - water column interface

2020 ◽  
Author(s):  
Mona Norbisrath
Keyword(s):  
Water Column ◽  
German Bight ◽  
Anthropogenic Impacts ◽  
Binding Capacity ◽  
Quantitative Relationship ◽  
Terminal Electron Acceptor ◽  
The North ◽  
In Situ Investigation ◽  
In Situ Experiments

<p><strong>Abstract: EGU 2020</strong></p><p><strong>Session: BG4.1: Biogeochemistry of coastal seas and continental shelves (Helmuth Thomas)</strong></p><p>Mona Norbisrath<sup>1</sup>, Kirstin Dähnke<sup>1</sup>, Andreas Neumann<sup>1</sup>, Justus van Beusekom<sup>1</sup>, Nele Treblin<sup>1</sup>, Bryce van Dam<sup>1</sup>, Helmuth Thomas<sup>1</sup></p><p><sup>1</sup>Institute for Coastal Research, Helmholtz-Zentrum Geesthacht</p><p>Contact: [email protected]</p><p> </p><p><strong>In-situ investigation of alkalinity - denitrification coupling in the sediment - water column interface</strong></p><p> </p><p>As a shallow shelf sea, the North Sea is very vulnerable to anthropogenic impacts like rising CO<sub>2</sub> concentrations, increasing nutrient inflows and coincident oxygen loss.</p><p>Two important processes that determine the role of the coastal ocean as a net sink for anthropogenic CO<sub>2</sub> are alkalinity and denitrification. Alkalinity, the acid binding capacity of the ocean, buffers natural and anthropogenic changes in the oceans’ CO<sub>2</sub> and pH system. Denitrification, an anaerobic microbial process in which organic matter is respired, uses NO<sub>3</sub><sup>-</sup> instead of O<sub>2</sub> as a terminal electron acceptor. Denitrification reduces NO<sub>3</sub><sup>-</sup> to N<sub>2</sub> and in turn produces alkalinity.</p><p>Eutrophication, caused by leaching of excess fertilizer nutrients into coastal seas, leads to enhanced denitrification and therefore to enhanced alkalinity as well as an increased uptake of CO<sub>2</sub>. However, the quantitative relationship between denitrification and alkalinity production and its control under changing environmental conditions is yet to be determined.</p><p>In the German Bight, denitrification is usually restricted to anoxic sediments. In this study, we therefore focus on in-situ experiments in the sediment - water column interface. Batch core incubations in combination with the isotope pairing technique (IPT) and labelled nitrate additions were used to detect denitrification and gauge its effect on alkalinity production during a cruise on RV Heincke (HE541) in September 2019 in the German Bight. To quantify denitrification, the production of all three N<sub>2</sub> isotope species (<sup>28</sup>N<sub>2</sub>, <sup>29</sup>N<sub>2</sub> and <sup>30</sup>N<sub>2</sub>) is measured using a membrane inlet mass spectrometer (MIMS). We expect an increase of denitrification rates with nitrate concentrations and incubation times, and we will quantify benthic denitrification. We will further evaluate the assumption of concurrent increases in alkalinity production and will investigate the benthic-pelagic coupling of these processes. Investigating the in-situ interaction of metabolic alkalinity and denitrification will give an estimation of the alkalinity impact on the reduction of anthropogenic CO<sub>2</sub> in the atmosphere.</p><p> </p>

scholarly journals In Situ Studies of Light Metals with Synchrotron Radiation and Neutrons

2011 ◽  
Vol 690 ◽  
pp. 192-197
Author(s):  
Peter Staron ◽  
Felix Beckmann ◽  
Thomas Lippmann ◽  
Andreas Stark ◽  
Michael Oehring ◽  
...  
Keyword(s):  
High Energy ◽  
High Time Resolution ◽  
Material Research ◽  
Light Metals ◽  
X Rays ◽  
Friction Stir ◽  
Wide Range ◽  
In Situ Experiments

High-energy X-rays and neutrons offer the large penetration depths that are often required for the determination of bulk properties in engineering material research. In addition, new sources provide very high intensities on the sample, which can be used not only for high spatial resolution using very small beams, but also for high time resolution in combination with a fast detector. This opens up possibilities for a wide range of specific engineering in situ experiments. Typical examples that are already widely used are heating or tensile testing in the beam. However, there are also more challenging experiments in the field of light metals, like e.g. friction stir welding, dilatometry, solidification, or cutting. Selected examples are presented.

scholarly journals Effects of Environmental Factors on the Leaching and Immobilization Behavior of Arsenic from Mudstone by Laboratory and In Situ Column Experiments

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1220
Author(s):  
Takahiko Arima ◽  
Ryosuke Sasaki ◽  
Takahiro Yamamoto ◽  
Carlito Baltazar Tabelin ◽  
Shuichi Tamoto ◽  
...  
Keyword(s):  
Water Content ◽  
Adsorption Layer ◽  
River Sediment ◽  
Column Experiments ◽  
Experimental Conditions ◽  
Natural Adsorbents ◽  
In Situ Experiments ◽  
As Adsorption ◽  
Laboratory Column

Hydrothermally altered rocks generated from underground/tunnel projects often produce acidic leachate and release heavy metals and toxic metalloids, such as arsenic (As). The adsorption layer and immobilization methods using natural adsorbents or immobilizer as reasonable countermeasures have been proposed. In this study, two sets of column experiments were conducted, of which one was focused on the laboratory columns and other on the in situ columns, to evaluate the effects of column conditions on leaching of As from excavated rocks and on adsorption or immobilization behavior of As by a river sediment (RS) as a natural adsorbent or immobilizer. A bottom adsorption layer consisting of the RS was constructed under the excavated rock layer or a mixing layer of the excavated rock and river sediment was packed in the column. The results showed that no significant trends in the adsorption and immobilization of As by the RS were observed by comparing laboratory and in situ column experiments because the experimental conditions did not influence significant change in the leachate pH which affects As adsorption or immobilization. However, As leaching concentrations of the in situ experiments were higher than those of the laboratory column experiments. In addition, the lower pH, higher Eh and higher coexisting sulfate ions of the leachate were observed for the in situ columns, compared to the results of the laboratory columns. These results indicate that the leaching concentration of As became higher in the in situ columns, resulting in higher oxidation of sulfide minerals in the rock. This may be due to the differences in conditions, such as temperature and water content, which induce the differences in the rate of oxidation of minerals contained in the rock. On the other hand, since the leachate pH affecting As adsorption or immobilization was not influenced significantly, As adsorption or immobilization effect by the RS were effective for both laboratory and in situ column experiments. These results indicate that both in situ and laboratory column experiments are useful in evaluating leaching and adsorption of As by natural adsorbents, despite the fact that the water content which directly affects the rate of oxidation is sensitive to weathering conditions.

scholarly journals Scale independence of till rheology

2006 ◽  
Vol 52 (178) ◽  
pp. 377-380 ◽  
Author(s):  
Slawek Tulaczyk
Keyword(s):  
Characteristic Length ◽  
West Antarctica ◽  
Ice Flow ◽  
Length Scales ◽  
Ice Stream ◽  
In Situ Experiments ◽  
Whillans Ice Stream ◽  
Speed Up

AbstractRepresentation of till rheology in glaciological models of ice motion over deformable sediments has, until now, focused largely on two end-member cases: (1) linear, or mildly non-linear, viscous rheology and (2) (nearly) plastic rheology. Most laboratory and in situ experiments support the latter model. Hindmarsh (1997) and Fowler (2002, 2003) proposed that experimental results represent the behavior of small till samples (characteristic length scales of ~0.1 to ~1 m) but that till behaves viscously over length scales that are relevant to determination of ice-flow rates in glaciers and ice sheets (~1 km or more). Observations of short speed-up events on the ice plain of Whillans Ice Stream, West Antarctica, provide an opportunity to compare the in situ rheology of this till, integrated over ~10–100 km, with the rheology of till from beneath the same ice stream determined on small laboratory samples and in local borehole experiments. This comparison indicates that the rheology of the subglacial till beneath Whillans Ice Stream is independent of scale.

In Situ Determination of Glass Transition Temperatures of Epoxy Adhesives in Structural Ceramic Assemblies

2011 ◽  
Vol 62 ◽  
pp. 107-116
Author(s):  
Valérie Nassiet ◽  
Bouchra Hassoune-Rhabbour ◽  
Yves Baziard
Keyword(s):  
Glass Transition ◽  
Thermomechanical Analysis ◽  
Epoxy Adhesive ◽  
Lap Joint ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Single Lap Joint ◽  
Epoxy Adhesives

A method is described for measuring the glass transition temperature (Tg) of epoxy joints bonding ceramic (SiC) substrates. This method is based on the strain measure of a single-lap joint subjected to a temperature variation. The resulting displacement (d) is observed as a function of the temperature (T) by means of a contact strain gauge extensometer. Thus Tg value can be determined using (d-T) curves recorded. The influence of joint parameters (joint thickness and overlap length) and of other parameters such as the applied load and the surface state of substrates were studied for a structural epoxy adhesive showing different thermomechanical behaviours. The results show that it is possible, with appropriate experimental conditions, to measure Tg with this method and to find Tg values similar to those found by classical techniques such as the static thermomechanical analysis (TMA) and the differential scanning calorimetry (DSC). This method shows similarities with TMA, but it has the advantage to allow the thermomechanical analysis of adhesives without destructive sampling of joints.

scholarly journals In situ straining experiments in the Transmission Electron Microscope

1990 ◽  
Vol 48 (4) ◽  
pp. 518-519
Author(s):  
Ulrich Messerschmidt
Keyword(s):  
Effective Stress ◽  
Line Tension ◽  
Prismatic Slip ◽  
Water Cooling ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Ordered Alloys ◽  
Kinematic Behaviour

Recently a number of in situ straining experiments have been carried out at temperatures between about 80 K and 1200 K. A new HVEM straining stage was constructed for temperatures above 1300 K. Its design features are: top entry double tilting stage, thermal expansion drive of high stiffness, heating by electron bombardment, and water cooling to quickly reach a steady state.The following deformation phenomena have successfully been treated by in situ experiments:Determination of the effective stress from the curvature of bowed-out dislocation segments: As shown by in situ experiments on MgO crystals, the line tension of dislocations may differ from its theoretical value. Nevertheless, the anomalous temperature dependence of the effective stress in ordered alloys as well as for prismatic slip in Be has been determined in accordance with macroscopic experiments. Measurement of velocities and kinematic behaviour of dislocations: In situ experiments allow the coordination of the motion of individual dislocation segments with their geometrical configuration.

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