scholarly journals Speed of sound gradients due to summer thermal stratification can reduce the detection range of acoustic fish tags: results from a field study in Hamilton Harbour, Ontario.

2020 ◽  
Author(s):  
Mathew G. Wells ◽  
Jingzhi Li ◽  
Bryan Flood ◽  
Yulong Kuai ◽  
Jill L. Brooks ◽  
...  
Keyword(s):  
Thermal Stratification ◽  
Thermal Gradients ◽  
Short Term ◽  
Detection Range ◽  
Hamilton Harbour ◽  
Key Factor ◽  
Range Testing ◽  
Derived Data ◽  
Internal Seiches ◽  
Range Test

Understanding detection range is a key factor for the use of acoustic telemetry in fisheries research. Lakes have strong seasonal changes in thermal stratification, as well as short-term changes due to internal seiches. These thermal gradients in lakes imply strong sound-speed gradients that can refract and diverge acoustic signals, leading to acoustic attenuation and smaller detection range. Using field-based range testing and the Bellhop acoustic model, we investigated how changes in stratification lead to changes in detection range within Hamilton Harbour, Ontario, Canada. During the summer stratified period, the detection range was less than 350 m, whereas in the isothermal fall, range was up to 500 m. Range test data from three separate field observations showed a good correlation with Bellhop predictions. Due to the intense internal seiches in Hamilton Harbour, the stratification in the shallower littoral regions essentially switched between stratified and isothermal conditions over short timescales, which is predicted to lead to high temporal variability in detection range that must be accounted for during the analysis and interpretation of telemetry derived data.

scholarly journals How big is the influence of biogenic silicon pools on short-term changes in water-soluble silicon in soils? Implications from a study of a 10-year-old soil–plant system

2017 ◽  
Vol 14 (22) ◽  
pp. 5239-5252 ◽  
Author(s):  
Daniel Puppe ◽  
Axel Höhn ◽  
Danuta Kaczorek ◽  
Manfred Wanner ◽  
Marc Wehrhan ◽  
...  
Keyword(s):  
Water Soluble ◽  
Small Scale ◽  
Testate Amoeba ◽  
Short Term ◽  
Plant Materials ◽  
Main Driver ◽  
Key Factor ◽  
Calamagrostis Epigejos ◽  
Biogenic Silicon ◽  
Future Work

Abstract. The significance of biogenic silicon (BSi) pools as a key factor for the control of Si fluxes from terrestrial to aquatic ecosystems has been recognized for decades. However, while most research has been focused on phytogenic Si pools, knowledge of other BSi pools is still limited. We hypothesized that different BSi pools influence short-term changes in the water-soluble Si fraction in soils to different extents. To test our hypothesis we took plant (Calamagrostis epigejos, Phragmites australis) and soil samples in an artificial catchment in a post-mining landscape in the state of Brandenburg, Germany. We quantified phytogenic (phytoliths), protistic (diatom frustules and testate amoeba shells) and zoogenic (sponge spicules) Si pools as well as Tiron-extractable and water-soluble Si fractions in soils at the beginning (t0) and after 10 years (t10) of ecosystem development. As expected the results of Tiron extraction showed that there are no consistent changes in the amorphous Si pool at Chicken Creek (Hühnerwasser) as early as after 10 years. In contrast to t0 we found increased water-soluble Si and BSi pools at t10; thus we concluded that BSi pools are the main driver of short-term changes in water-soluble Si. However, because total BSi represents only small proportions of water-soluble Si at t0 (< 2 %) and t10 (2.8–4.3 %) we further concluded that smaller (< 5 µm) and/or fragile phytogenic Si structures have the biggest impact on short-term changes in water-soluble Si. In this context, extracted phytoliths (> 5 µm) only amounted to about 16 % of total Si contents of plant materials of C. epigejos and P. australis at t10; thus about 84 % of small-scale and/or fragile phytogenic Si is not quantified by the used phytolith extraction method. Analyses of small-scale and fragile phytogenic Si structures are urgently needed in future work as they seem to represent the biggest and most reactive Si pool in soils. Thus they are the most important drivers of Si cycling in terrestrial biogeosystems.

scholarly journals Lower-crustal rheology and thermal gradient in the Taiwan orogenic belt illuminated by the 1999 Chi-Chi earthquake

2019 ◽  
Vol 5 (2) ◽  
pp. eaav3287 ◽  
Author(s):  
Chi-Hsien Tang ◽  
Ya-Ju Hsu ◽  
Sylvain Barbot ◽  
James D. P. Moore ◽  
Wu-Lung Chang
Keyword(s):  
Tectonic Evolution ◽  
Laboratory Data ◽  
Orogenic Belt ◽  
Thermal Gradients ◽  
Short Term ◽  
Crustal Strength ◽  
Seismic Cycles ◽  
Natural Settings ◽  
Stress And Strain Rate ◽  
Lower Crustal

The strength of the lithosphere controls tectonic evolution and seismic cycles, but how rocks deform under stress in their natural settings is usually unclear. We constrain the rheological properties beneath the Taiwan orogenic belt using the stress perturbation following the 1999 Chi-Chi earthquake and fourteen-year postseismic geodetic observations. The evolution of stress and strain rate in the lower crust is best explained by a power-law Burgers rheology with rapid increases in effective viscosities from ~1017to ~1019Pa s within a year. The short-term modulation of the lower-crustal strength during the seismic cycle may alter the energy budget of mountain building. Incorporating the laboratory data and associated uncertainties, inferred thermal gradients suggest an eastward increase from 19.5±2.5°C/km in the Coastal Plain to 32±3°C/km in the Central Range. Geodetic observations may bridge the gap between laboratory and lithospheric scales to investigate crustal rheology and tectonic evolution.

Heat uptake and resistance to mixing in small humic forest lakes in Southern Finland

1990 ◽  
Vol 41 (6) ◽  
pp. 747 ◽  
Author(s):  
LC Bowling ◽  
K Salonen
Keyword(s):  
Thermal Stratification ◽  
Heat Of Fusion ◽  
Short Term ◽  
Thermal Stabilities ◽  
Maximum Heat ◽  
Lake Volume ◽  
Heat Uptake ◽  
Forest Lakes ◽  
Heat Budgets ◽  
Term Fluctuation

The annual heat budgets and maximum thermal stabilities achieved by small Finnish forest lakes are considerable for lakes of their size. Heat uptake is rapid during the brief period of vernal circulation, with the latent heat of fusion of ice contributing substantially to this. Heating then slows, with maximum heat contents and thermal stabilities occurring around early August. Absorption of solar radiation by the dystrophic waters, effective shelter from wind-induced turbulence, and considerable relative depths all combine to prevent mixing of heat much below the surface 2 m of most study lakes. Birgean wind-work values therefore remain low, and cold hypolimnetic waters occupy much of the lake volume. The lakes also respond quickly to meteorological change, which causes considerable year-to-year variation, and some short-term fluctuation, in their heat budgets and maximum stabilities. The lakes' small size and shallow thermal stratification may contribute to this.

scholarly journals DINAMIKA KEHIDUPAN MANUSIA DAN KONDISI SUMBERDAYA ALAM DAERAH ALIRAN SUNGAI

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Elvi Zuriyani
Keyword(s):  
Literature Review ◽  
Natural Resources ◽  
Natural Disasters ◽  
Watershed Management ◽  
Short Term ◽  
The Public ◽  
Key Factor ◽  
The Government ◽  
Resource Conditions ◽  
Watershed Degradation

The purpose of writing this article is to give an overview of watershed damage that has occurred, which also led to the occurrence of natural disasters. Watershed damage that occurs due to the interaction between human and natural resources show that the interaction is negative in the end will result in damage and natural disasters. This paper is a literature review on the analysis of the facts that occurred on the field of natural resource conditions watersheds, as well as in the analysis of the theories associated with pegelolaan DAS. Based on the problems and phenomena of watershed degradation that has occurred in recent years, it is necessary efforts and strategies for watershed management that are useful for the realization of the sustainability of the watershed for the present and future. Cooperation between the public and the government in watershed management is the key factor required. The government must be able to move the various stakeholders in the management of natural resources, including natural resources watersheds, through policies, strategies, and programs to both short term and long term.Keywords: dynamics, human, watershed resources.

scholarly journals Onshore–offshore gradient in metacommunity turnover emerges only over macroevolutionary time-scales

2014 ◽  
Vol 281 (1795) ◽  
pp. 20141533 ◽  
Author(s):  
Adam Tomašových ◽  
Stefano Dominici ◽  
Martin Zuschin ◽  
Didier Merle
Keyword(s):  
Time Scales ◽  
Thermal Gradients ◽  
Short Term ◽  
Northeast Atlantic ◽  
Atlantic Province ◽  
Temporal Turnover ◽  
Warm Temperate ◽  
Molluscan Species

Invertebrate lineages tend to originate and become extinct at a higher rate in onshore than in offshore habitats over long temporal durations (more than 10 Myr), but it remains unclear whether this pattern scales down to durations of stages (less than 5 Myr) or even sequences (less than 0.5 Myr). We assess whether onshore–offshore gradients in long-term turnover between the tropical Eocene and the warm-temperate Plio-Pleistocene can be extrapolated from gradients in short-term turnover, using abundances of molluscan species from bulk samples in the northeast Atlantic Province. We find that temporal turnover of metacommunities does not significantly decline with depth over short durations (less than 5 Myr), but significantly declines with depth between the Eocene and Plio-Pleistocene (approx. 50 Myr). This decline is determined by a higher onshore extinction of Eocene genera and families, by a higher onshore variability in abundances of genera and families, and by an onshore expansion of genera and families that were frequent offshore in the Eocene. Onshore–offshore decline in turnover thus emerges only over long temporal durations. We suggest that this emergence is triggered by abrupt and spatially extensive climatic or oceanographic perturbations that occurred between the Eocene and Plio-Pleistocene. Plio-Pleistocene metacommunities show a high proportion of bathymetric generalists, in contrast to Eocene metacommunities. Accordingly, the net cooling and weaker thermal gradients may have allowed offshore specialists to expand into onshore habitats and maintain their presence in offshore habitats.

The effects of a short-term music program on preschool children’s executive functions

2017 ◽  
Vol 45 (6) ◽  
pp. 855-867 ◽  
Author(s):  
Jennifer A. Bugos ◽  
Darlene DeMarie
Keyword(s):  
Executive Functions ◽  
Repeated Measures ◽  
Verbal Response ◽  
Short Term ◽  
Gross Motor ◽  
Neuropsychological Measures ◽  
Music Program ◽  
Key Factor ◽  
Inhibition Performance ◽  
Preschool Music

The purpose of this study was to examine the effects of a short-term preschool music program with creativity, bimanual gross motor training, and vocal development on preschool children’s inhibition. Inhibition is the key factor in preschool children’s executive functions development between 3–5 years. Thirty-six preschool children were randomly assigned to music or Lego training, a comparable control task. We administered neuropsychological measures pre- and post-training. Results of a repeated measures ANOVA on the Matching Familiar Figures Test (MFFT), a task requiring inhibition and visual discrimination, indicated a significant time by group interaction, with fewer errors committed post-training by the music group compared to controls. However, only a main effect of time was found for the second inhibition task, the Day/Night Stroop Task, a task requiring inhibition of a dominant verbal response. Music training in early childhood that includes an emphasis on bimanual coordination in gross motor movements may contribute to enhanced inhibition performance on complex tasks.

A review of detection range testing in aquatic passive acoustic telemetry studies

2013 ◽  
Vol 24 (1) ◽  
pp. 199-218 ◽  
Author(s):  
S. T. Kessel ◽  
S. J. Cooke ◽  
M. R. Heupel ◽  
N. E. Hussey ◽  
C. A. Simpfendorfer ◽  
...  
Keyword(s):  
Acoustic Telemetry ◽  
Detection Range ◽  
Range Testing ◽  
Passive Acoustic

A Comparison of Methods for Assessment of Nutrient Deficiency of Phytoplankton in a Large Oligotrophic Lake

1990 ◽  
Vol 47 (12) ◽  
pp. 2328-2338 ◽  
Author(s):  
Walter K. Dodds ◽  
John C. Priscu
Keyword(s):  
Thermal Stratification ◽  
Carbon Fixation ◽  
Algal Growth ◽  
Nutrient Deficiency ◽  
Short Term ◽  
P Deficiency ◽  
Flathead Lake ◽  
Dark Carbon Fixation ◽  
Nutrient Amendments

Short-term (h) and Song-term (d) changes in phytoplankton community physiology and bsomass in response to nutrient enrichment were used concomitantly as bioassays of phytoplankton nutrient deficiency in oligotrophic Flathead Lake, Montana, six times over the course of a year. Long-term bioassays consisted of nutrient amendments to epilimnetic water in 20 L containers which were subsequently monitored for algal growth. Short-term bioassays included measurement of NH4+ stimulation of dark carbon fixation, measurement of PO43− and NH4+ uptake over time to assess depletion of internal pools and stimulation effects of PO43− on NH4+ uptake and NH4+ on PO43− uptake. During thermal stratification, simultaneous additions of NH4+ and PO43− in long-term bioassays caused significant increases in chlorophyll a concentration, photosynthetic 14CO2 uptake, and particulate N concentration within 4.5 d; single additions of NH4+ or PO43− had little or no effect. During winter mixing there was little evidence for N or P deficiency in either short- or long-term bioassays. In general, short-term bioassays did not consistently agree with each other or with long-term bioassays. Our results suggest that it may be necessary to elicit growth of phytoplankton with nutrient addition to make definitive statements regarding nutrient deficiency.

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.

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