scholarly journals Strong thermal stratification reduces detection efficiency and range of acoustic telemetry in a large freshwater lake

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Yulong Kuai ◽  
Natalie V. Klinard ◽  
Aaron T. Fisk ◽  
Timothy B. Johnson ◽  
Edmund A. Halfyard ◽  
...  
Keyword(s):  
Great Lakes ◽  
Speed Of Sound ◽  
Sound Speed ◽  
Acoustic Telemetry ◽  
Thermal Stratification ◽  
Detection Efficiency ◽  
Late Summer ◽  
Lake Ontario ◽  
Sound Waves ◽  
Detection Range

Abstract Background The successful use of acoustic telemetry to detect fish hinges on understanding the factors that control the acoustic range. The speed-of-sound in water is primarily a function of density, and in freshwater lakes density is primarily driven by temperature. The strong seasonal thermal stratification in the Great Lakes represent some of the steepest sound speed gradients in any aquatic system. Such speed-of-sound gradients can refract sound waves leading to greater divergence of acoustic signal, and hence more rapid attenuation. The changes in sound attenuation change the detection range of a telemetry array and hence influence the ability to monitor fish. We use 3 months of data from a sentinel array of V9 and V16 Vemco acoustic fish tags, and a record of temperature profiles to determine how changes in stratification influence acoustic range in eastern Lake Ontario. Result We interpret data from an acoustic telemetry array in Lake Ontario to show that changes in acoustic detection efficiency and range correlate strongly with changes in sound speed gradients due to thermal stratification. The steepest sound speed gradients of 10.38 m s−1/m crossing the thermocline occurred in late summer, which caused the sound speed difference between the top and bottom of the water column to be greater than 60 m/s. V9 tags transmitting across the thermocline could have their acoustic range reduced from > 650 m to 350 m, while the more powerful V16 tags had their range reduced from > 650 m to 450 m. In contrast we found that when the acoustic source and receiver were both transmitting below thermocline there was no change in range, even as the strength of sound speed gradient varied. Conclusion Changes in thermal stratification occur routinely in the Great Lakes, on timescales between months and days. The acoustic range can be reduced by as much as 50% compared to unstratified conditions when fish move across the thermocline. We recommend that researchers consider the influences of thermal stratification to acoustic telemetry when configuring receiver position.

scholarly journals Strong Thermal Stratification Reduces Detection Efficiency and Range of Acoustic Telemetry in a Large Freshwater Lake

2021 ◽  
Author(s):  
Yulong Kuai ◽  
Natalie Klinard ◽  
Aaron Fisk ◽  
Timothy Johnson ◽  
Edmund Halfyard ◽  
...  
Keyword(s):  
Great Lakes ◽  
Speed Of Sound ◽  
Sound Speed ◽  
Acoustic Telemetry ◽  
Thermal Stratification ◽  
Detection Efficiency ◽  
Late Summer ◽  
Lake Ontario ◽  
Sound Waves ◽  
Detection Range

Abstract BackgroundThe successful use of acoustic telemetry to detect fish hinges on understanding the factors that control the acoustic range. The speed-of-sound in water is primarily a function of density, and in freshwater lakes density is primarily driven by temperature. The seasonal thermal stratification in the Great Lakes represent the strongest sound speed gradients in any aquatic system. Such speed-of-sound gradients can refract sound waves leading to greater divergence of acoustic signal, and hence more rapid attenuation. The changes in sound attenuation change the detection range of a telemetry array and hence influence the ability to monitor fish. We use three months of data from a sentinel array of V9 and V16 Vemco acoustic fish tags, and a record of temperature profiles to determine how changes in stratification influence acoustic range in eastern Lake Ontario. ResultWe interpret data from an acoustic telemetry array in Lake Ontario to show that changes in acoustic detection efficiency and range correlate strongly with changes in sound speed gradients due to thermal stratification. The strongest sound speed gradients of 10.38 ms-1/m crossing the thermocline occurred in late summer, which caused the sound speed difference between the top and bottom of the water column to be greater than 60 m/s. V9 tags transmitting across the thermocline could have their acoustic range reduced from >650 m to 350 m, while the more powerful V16 tags had their range reduced from >650 m to 450 m. In contrast we found that when the acoustic source and receiver were both transmitting below thermocline there was no change in range, even as the strength of sound speed gradient varied. ConclusionChanges in thermal stratification occur routinely in the Great Lakes, on timescales between months and days. The acoustic range can be reduced by as much as 50% compared to unstratified conditions when fish move across the thermocline. We recommend that researchers consider the influences of thermal stratification to acoustic telemetry when configuring receiver position.

Phosphorus Enrichment, Silica Utilization, and Biogeochemical Silica Depletion in the Great Lakes

1986 ◽  
Vol 43 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Claire L. Schelske ◽  
Eugene F. Stoermer ◽  
Gary L. Fahnenstiel ◽  
Mark Haibach
Keyword(s):  
Steady State ◽  
Great Lakes ◽  
Urban Population ◽  
Thermal Stratification ◽  
Lake Erie ◽  
Lake Michigan ◽  
Lake Ontario ◽  
Lake Huron ◽  
Phosphorus Enrichment

Our hypothesis that silica (Si) depletion in Lake Michigan and the severe Si depletion that characterizes the lower Great Lakes were induced by increased phosphorus (P) inputs was supported by bioassay experiments showing increased Si uptake by diatoms with relatively small P enrichments. We propose that severe Si depletion (Si concentrations being reduced to ≤0.39 mg SiO2∙L−1 prior to thermal stratification) results when P levels are increased to the extent that increased diatom production reduces Si concentrations to limiting levels during the thermally mixed period. Large P enrichments such as those that characterized the eastern and central basis of Lake Erie and Lake Ontario in the early 1970s are necessary to produce severe Si depletion. It is clear that severe Si depletion in the lower lakes was produced by P enrichment because inflowing waters from Lake Huron have smaller P concentrations and larger Si concentrations than the outflowing waters of either Lake Erie or Lake Ontario. Severe Si depletion probably began in the 1940s or 1950s as the result of increased P loads from expanded sewering of an increasing urban population and the introduction of phosphate detergents. The model proposed for biogeochemical Si depletion is consistent with previous findings of high rates of internal recycling because, under steady-state conditions for Si inputs, any increase in diatom production will produce an increase in permanent sedimentation of biogenic Si provided some fraction of the increased biogenic Si production is not recycled or unless there is a compensating increase in dissolution of diatoms.

scholarly journals Detection range and efficiency of acoustic telemetry receivers in a connected wetland system

Hydrobiologia ◽  
2021 ◽  
Vol 848 (8) ◽  
pp. 1825-1836
Author(s):  
Emily R. Winter ◽  
Andrew M. Hindes ◽  
Steve Lane ◽  
J. Robert Britton
Keyword(s):  
Water Temperature ◽  
Acoustic Telemetry ◽  
Detection Efficiency ◽  
Acoustic Noise ◽  
Chlorophyll Concentration ◽  
Temperature Conductivity ◽  
Detection Range ◽  
Receiver Performance ◽  
Range Testing

AbstractAcoustic telemetry is an important tool for assessing the behavioural ecology of aquatic animals, but the performance of receivers can vary spatially and temporally according to changes in environmental gradients. Studies testing detection efficiency and/ or detection range are, therefore, important for data interpretation, although the most thorough range-testing approaches are often costly or impractical, such as the use of fixed sentinel tags. Here, stationary tag data (from study animals that had either died or expelled their tags) provided a substitute for the long-term monitoring of receiver performance in a wetland environment and was complemented by periodic boat-based range testing, with testing of the effects of environmental variables (water temperature, conductivity, transparency, precipitation, wind speed, acoustic noise) on detection efficiency (DE) and detection range (DR). Stationary tag DE was highly variable temporally, the most influential factors being water temperature and precipitation. Transparency was a strong predictor of DR and was dependent on chlorophyll concentration (a surrogate measure of algal density). These results highlight the value of stationary tag data in assessments of acoustic receiver performance. The high seasonal variability in DE and DR emphasises the need for long-term receiver monitoring to enable robust conclusions to be drawn from telemetry data.

Zebra Mussels as Biomonitors for Organic Contaminants in the Lower Great Lakes

1996 ◽  
Vol 31 (2) ◽  
pp. 411-432 ◽  
Author(s):  
Michael E. Comba ◽  
Janice L. Metcalfe-Smith ◽  
Klaus L.E. Kaiser
Keyword(s):  
Great Lakes ◽  
Organic Contaminants ◽  
Lake Erie ◽  
Soft Tissues ◽  
Lake Ontario ◽  
Dry Weight ◽  
Zebra Mussels ◽  
Organic Contamination ◽  
Contamination Levels ◽  
St Lawrence River

Abstract Zebra mussels were collected from 24 sites in Lake Erie, Lake Ontario and the St. Lawrence River between 1990 and 1992. Composite samples of whole mussels (15 sites) or soft tissues (9 sites) were analyzed for residues of organochlo-rine pesticides and PCBs to evaluate zebra mussels as biomonitors for organic contaminants. Mussels from most sites contained measurable quantities of most of the analytes. Mean concentrations were (in ng/g, whole mussel dry weight basis) 154 ΣPCB, 8.4 ΣDDT, 3.5 Σchlordane, 3.4 Σaldrin, 1.4 ΣBHC, 1.0 Σendosulfan, 0.80 mirex and 0.40 Σchlorobenzene. Concentrations varied greatly between sites, i.e., from 22 to 497 ng/g for ΣPCB and from 0.08 to 11.6 ng/g for ΣBHC, an indication that mussels are sensitive to different levels of contamination. Levels of ΣPCB and Σendosulfan were highest in mussels from the St. Lawrence River, whereas mirex was highest in those from Lake Ontario. Overall, mussels from Lake Erie were the least contaminated. These observations agree well with the spatial contaminant trends shown by other biomoni-toring programs. PCB congener class profiles in zebra mussels are also typical for nearby industrial sources, e.g., mussels below an aluminum casting plant contained 55% di-, tri- and tetrachlorobiphenyls versus 31% in those upstream. We propose the use of zebra mussels as biomonitors of organic contamination in the Great Lakes.

scholarly journals The influence of dynamic environmental interactions on detection efficiency of acoustic transmitters in a large, deep, freshwater lake

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Natalie V. Klinard ◽  
Edmund A. Halfyard ◽  
Jordan K. Matley ◽  
Aaron T. Fisk ◽  
Timothy B. Johnson
Keyword(s):  
Study Design ◽  
Environmental Conditions ◽  
Power Output ◽  
Environmental Variables ◽  
Acoustic Telemetry ◽  
Detection Efficiency ◽  
Data Interpretation ◽  
Heterogeneous Environments ◽  
Depth Range ◽  
Dynamic Relationship

Abstract Background Acoustic telemetry is an increasingly common method used to address ecological questions about the movement, behaviour, and survival of freshwater and marine organisms. The variable performance of acoustic telemetry equipment and ability of receivers to detect signals from transmitters have been well studied in marine and coral reef environments to inform study design and improve data interpretation. Despite the growing use of acoustic telemetry in large, deep, freshwater systems, detection efficiency and range, particularly in relation to environmental variation, are poorly understood. We used an array of 90 69-kHz acoustic receivers and 8 sentinel range transmitters of varying power output deployed at different depths and locations approximately 100–9500 m apart for 215 days to evaluate how the detection efficiency of acoustic receivers varied spatially and temporally in relation to environmental conditions. Results The maximum distance that tags were detected ranged from 5.9 to 9.3 km. Shallow tags consistently had lower detection efficiency than deep tags of the same power output and detection efficiency declined through the winter months (December–February) of the study. In addition to the distance between tag and receiver, thermocline strength, surface water velocity, ice thickness, water temperature, depth range between tag and receiver, and number of fish detections contributed to explaining variation in detection efficiency throughout the study period. Furthermore, the most significant models incorporated interactions between several environmental variables and tag–receiver distance, demonstrating the complex temporal and spatial relationships that exist in heterogeneous environments. Conclusions Relying on individual environmental variables in isolation to interpret receiver performance, and thus animal behaviour, may be erroneous when detection efficiency varies across distances, depths, or tag types. As acoustic telemetry becomes more widely used to study ecology and inform management, it is crucial to understand its limitations in heterogeneous environments, such as freshwater lakes, to improve the quality and interpretation of data. We recommend that in situ range testing and retrospective analysis of detection efficiency be incorporated into study design for telemetry projects. Furthermore, we caution against oversimplifying the dynamic relationship between detection efficiency and environmental conditions for the sake of producing a correction that can be applied directly to detection data of tagged animals when the intended correction may not be justified.

Sound speed in pulmonary parenchyma

1983 ◽  
Vol 54 (1) ◽  
pp. 304-308 ◽  
Author(s):  
D. A. Rice
Keyword(s):  
Lung Volume ◽  
Sound Speed ◽  
Sulfur Hexafluoride ◽  
Ambient Pressure ◽  
Linear Regression Analysis ◽  
Free Field ◽  
Average Density ◽  
Sound Waves ◽  
Gas Phases ◽  
Audible Sound

The time it takes audible sound waves to travel across a lobe of excised horse lung was measured. Sound speed, which is the slope in the relationship between transit time and distance across the lobe, was estimated by linear regression analysis. Sound-speed estimates for air-filled lungs varied between 25 and 70 m/s, depending on lung volume. These speeds are less than 5% of sound speed in tissue and less than 20% of sound speed in air. Filling the lung with helium or sulfur hexafluoride, whose free-field sound speeds are 970 and 140 m/s, respectively, changed sound speed +/- 10% relative to air filling. Reducing the ambient pressure to 0.1 atm reduced sound speed to 30% of its 1-atm value. Increasing pressure to 7 atm increased sound speed by a factor of 2.6. These results suggest that 1) translobar sound travels through the bulk of the parenchyma and not along airways or blood vessels, and 2) the parenchyma acts as an elastic continuum to audible sound. The speed of sound is given by c = (B/rho)1/2, where B is composite volumetric stiffness of the medium and rho is average density. In the physiologic state B is affected by ambient pressure and percent gas phase. The average density includes both the tissue and gas phases of the parenchyma, so it is dependent on lung volume. These results may be helpful in the quantification of clinical observations of lung sounds.

Theory of the rocket-grenade method of measuring temperature, pressure, density and wind velocity in the upper atmosphere

1966 ◽  
Vol 290 (1420) ◽  
pp. 44-73 ◽  
Keyword(s):  
Experimental Data ◽  
Least Squares ◽  
Wind Velocity ◽  
Speed Of Sound ◽  
Vertical Component ◽  
Second Order ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Travel Times ◽  
Sound Waves

A theory is presented for deriving the speed of sound and wind velocity as a function of height in the upper atmosphere from observations on the travel times of sound waves from accurately located grenades, released during rocket flight, to microphones at surveyed positions on the ground. The theory is taken to a second order of approximation, which can be utilized in practice if lower atmosphere (balloon) measurements are available. By means of the gas law and the vertical equation of motion of the atmosphere, formulae are obtained for deriving temperature, pressure and density from the speed-of-sound profile, and these also may be evaluated to a higher accuracy if lower atmosphere measurements are available. An outline is given of the computational procedure followed in the processing of data on the basis of this theory by means of the Pegasus computer. Methods of calculating the correction to travel times due to the finite wave amplitude are discussed and compared, and the effect of neglecting this correction in a particular set of experimental data is examined. Other errors which may affect the determination of pressure are also discussed. Consistency between the theory and experimental data obtained in 13 Skylark rocket flights at Woomera is checked in two ways: by examining least squares residuals associated with the sound arrivals at various microphones; and by treating the vertical component of air motion as unknown and examining its distribution about zero. The reduction in the least squares residuals which occurs when account is taken of second order terms is evaluated on the basis of these sets of experimental data.

20. The Description to Look Down on All Opposition”: The Remains of HMS St. Lawrence

2018 ◽  
Author(s):  
Aaron Styba
Keyword(s):  
Great Lakes ◽  
Lake Ontario ◽  
Balance Of Power ◽  
War Of 1812 ◽  
Western Hemisphere ◽  
Nuclear Bomb ◽  
Joint Investigation ◽  
Queen's University ◽  
Parks Canada

In one of the most ignominious wars in history, a combined force of British and Canadian soldiers, sailors and civilians constructed the largest wooden warship ever built in the western hemisphere. Engaged with the Americans in a desperate game of cat-and-mouse upon Lake Ontario, the massive warship HMS St. Lawrence swung the balance of power firmly in favour of the British and thereby hastened the signing of the Treaty of Ghent, bringing the War of 1812 to a sputtering halt.This colossal warship, over 200 feet long, crewed by 700 and carrying 112 cannon, was completed at Kingston, Ontario in little over 9 months. Patrolling Lake Ontario, HMS St. Lawrence immediately caused the Americans to flee to their harbour. Astoundingly, and in a very Canadian fashion, she never fired a shot in combat.After the war ended, years of disrepair and dereliction left HMS St. Lawrence as a hulk of her former self. Sold to a local entrepreneur for a measly £25, she found herself towed to a location near Queen’s University. Mysteriously, she then disappeared from history. After the consideration of several theories, the hope is that this presentation, based upon the research conducted in a joint investigation by Parks Canada, the Marine Museum of the Great Lakes and Queen’s University, will help determine the fate of this “nuclear bomb of her age.”This presentation will outline the fascinating origins of HMS St. Lawrence, how she was archaeological documented, what the investigation tells us, and why investigating naval heritage is a worthy undertaking.

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