scholarly journals Narwhals react to ship noise and airgun pulses embedded in background noise

2021 ◽  
Vol 17 (11) ◽  
Author(s):  
Outi M. Tervo ◽  
Susanna B. Blackwell ◽  
Susanne Ditlevsen ◽  
Alexander S. Conrad ◽  
Adeline L. Samson ◽  
...  
Keyword(s):  
High Frequency ◽  
Background Noise ◽  
Site Fidelity ◽  
Anthropogenic Activities ◽  
The Arctic ◽  
Exposure Study ◽  
Sound Exposure ◽  
Monodon Monoceros ◽  
Exposure Levels ◽  
Extreme Sensitivity

Anthropogenic activities are increasing in the Arctic, posing a threat to niche-conservative species with high seasonal site fidelity, such as the narwhal Monodon monoceros . In this controlled sound exposure study, six narwhals were live-captured and instrumented with animal-borne tags providing movement and behavioural data, and exposed to concurrent ship noise and airgun pulses. All narwhals reacted to sound exposure with reduced buzzing rates, where the response was dependent on the magnitude of exposure defined as 1/distance to ship. Buzzing rate was halved at 12 km from the ship, and whales ceased foraging at 7–8 km. Effects of exposure could be detected at distances > 40 km from the ship.At only a few kilometres from the ship, the received high-frequency cetacean weighted sound exposure levels were below background noise indicating extreme sensitivity of narwhals towards sound disturbance and demonstrating their ability to detect signals embedded in background noise. The narwhal's reactions to sustained disturbance may have a plethora of consequences both at individual and population levels. The observed reactions of the whales demonstrate their auditory sensitivity but also emphasize, that anthropogenic activities in pristine narwhal habitats needs to be managed carefully if healthy narwhal populations are to be maintained.

scholarly journals Behavioral Response Study on Seismic Airgun and Vessel Exposures in Narwhals

2021 ◽  
Vol 8 ◽  
Author(s):  
Mads Peter Heide-Jørgensen ◽  
Susanna B. Blackwell ◽  
Outi M. Tervo ◽  
Adeline L. Samson ◽  
Eva Garde ◽  
...  
Keyword(s):  
Noise Exposure ◽  
Anthropogenic Activities ◽  
Travel Speed ◽  
The Arctic ◽  
Line Of Sight ◽  
Long Term Effects ◽  
Sound Exposure ◽  
Ice Coverage ◽  
Exposure Levels

One of the last pristine marine soundscapes, the Arctic, is exposed to increasing anthropogenic activities due to climate-induced decrease in sea ice coverage. In this study, we combined movement and behavioral data from animal-borne tags in a controlled sound exposure study to describe the reactions of narwhals, Monodon monoceros, to airgun pulses and ship noise. Sixteen narwhals were live captured and instrumented with satellite tags and Acousonde acoustic-behavioral recorders, and 11 of them were exposed to airgun pulses and vessel sounds. The sound exposure levels (SELs) of pulses from a small airgun (3.4 L) used in 2017 and a larger one (17.0 L) used in 2018 were measured using drifting recorders. The experiment was divided into trials with airgun and ship-noise exposure, intertrials with only ship-noise, and pre- and postexposure periods. Both trials and intertrials lasted ∼4 h on average per individual. Depending on the location of the whales, the number of separate exposures ranged between one and eight trials or intertrials. Received pulse SELs dropped below 130 dB re 1 μPa2 s by 2.5 km for the small airgun and 4–9 km for the larger airgun, and background noise levels were reached at distances of ∼3 and 8–10.5 km, respectively, for the small and big airguns. Avoidance reactions of the whales could be detected at distances >5 km in 2017 and >11 km in 2018 when in line of sight of the seismic vessel. Meanwhile, a ∼30% increase in horizontal travel speed could be detected up to 2 h before the seismic vessel was in line of sight. Applying line of sight as the criterion for exposure thus excludes some potential pre-response effects, and our estimates of effects must therefore be considered conservative. The whales reacted by changing their swimming speed and direction at distances between 5 and 24 km depending on topographical surroundings where the exposure occurred. The propensity of the whales to move towards the shore increased with increasing exposure (i.e., shorter distance to vessels) and was highest with the large airgun used in 2018, where the whales moved towards the shore at distances of 10–15 km. No long-term effects of the response study could be detected.

Aircraft noise-induced awakenings are more reasonably predicted from relative than from absolute sound exposure levels

2013 ◽  
Vol 134 (5) ◽  
pp. 3645-3653 ◽  
Author(s):  
Sanford Fidell ◽  
Barbara Tabachnick ◽  
Vincent Mestre ◽  
Linda Fidell
Keyword(s):  
Aircraft Noise ◽  
Sound Exposure ◽  
Exposure Levels

scholarly journals Background noise analysis in urban airport surroundings of Brazilian cities, Congonhas Airport, São Paulo

2016 ◽  
Vol 50 (0) ◽  
Author(s):  
Fabio Scatolini ◽  
Cláudio Jorge Pinto Alves
Keyword(s):  
Traffic Control ◽  
Background Noise ◽  
Noise Analysis ◽  
Exposure Level ◽  
Noise Levels ◽  
Sound Exposure ◽  
Operational Characteristics ◽  
Data Compilation ◽  
Noise Measurements ◽  
Noise Data

ABSTRACT OBJECTIVE To perform a quantitative analysis of the background noise at Congonhas Airport surroundings based on large sampling and measurements with no interruption. METHODS Measuring sites were chosen from 62 and 72 DNL (day-night-level) noise contours, in urban sites compatible with residential use. Fifteen sites were monitored for at least 168 hours without interruption or seven consecutive days. Data compilation was based on cross-reference between noise measurements and air traffic control records, and results were validated by airport meteorological reports. Preliminary diagnoses were established using the standard NBR-13368. Background noise values were calculated based on the Sound Exposure Level (SEL). Statistic parameters were calculated in one-hour intervals. RESULTS Only four of the fifteen sites assessed presented aircraft operations as a clear cause for the noise annoyance. Even so, it is possible to detect background noise levels above regulation limits during periods of low airport activity or when it closes at night. CONCLUSIONS All the sites monitored showed background noise levels above regulation limits between 7:00 and 21:00. In the intervals between 6:00-6:59 and 21:00-22:59 the noise data, when analyzed with the current airport operational characteristics, still allow the development of additional mitigating measures.

scholarly journals Application of high-frequency spring discharge data: a case study of Mathamali spring rejuvenation in the Garhwal Himalaya

2020 ◽  
Vol 20 (8) ◽  
pp. 3380-3392
Author(s):  
Vikram Kumar ◽  
Santosh Paramanik
Keyword(s):  
High Frequency ◽  
Anthropogenic Activities ◽  
Maximum Flow ◽  
Garhwal Himalaya ◽  
Spring Discharge ◽  
Post Intervention ◽  
Storage Duration ◽  
Discharge Data ◽  
Average Flow ◽  
Average Maximum

Abstract Water scarcity is becoming the biggest threat to the global population due to unpredictable rainfall, glaciers melt, and other anthropogenic activities. This study focuses on the analysis of monitored high-frequency continuous spring discharge and rainfall data in the contact and fracture type Mathamali spring located in the Garhwal Himalaya. Discharge from the spring and its storage behavior has been studied by analyzing recession components and flow duration curves. Analyzed discharge data revealed that the spring can generate maximum volume during monsoon as compared to winter due to aquifer properties and tendencies to store and transmit water. Springshed intervention practices were implemented in early April 2017. The measured average flow was 16.9 lpm but soon after the interventions, the average flow increased by 2.6 times. The minimum average spring flow was 2.3 lpm which increased by 5 times whereas the average maximum flow increased by 1.8 times. Post-intervention, storage duration has increased by 16%, decaying from 143 lpm (peak flow) to 12.7 lpm (baseflow). The preliminary findings from this spring can be considered as a check for establishing benchmarks for sustainable development of springsheds, climate change adaptation, and development plans to cope up with growing water insecurity in the rural Himalayas.

Lena River biogeochemistry resolved by a high frequency monitoring: comparing a wet and a dry year

2021 ◽  
Author(s):  
Bennet Juhls ◽  
Anne Morgenstern ◽  
Pier Paul Overduin
Keyword(s):  
Organic Carbon ◽  
High Frequency ◽  
Monitoring Program ◽  
The Arctic ◽  
Lena River ◽  
O Isotopes ◽  
The Arctic Ocean ◽  
Frequency Monitoring ◽  
Biogeochemical Parameters ◽  
Doc Flux

<p>River biogeochemistry at any location integrates environmental processes over a definable upstream area of the river watershed. Therefore, biogeochemical parameters of river water are powerful indicators of the climate change impact on the entire watershed and smaller parts of it.</p><p>The current warming of the Siberian Arctic is changing atmospheric forcing, precipitation, subsurface water storage, and runoff from rivers to the Arctic Ocean. A number of studies predict an increase of organic carbon export by rivers into the Arctic Ocean with further warming of the Arctic. Major potential drivers for this increase are the rise of river discharge and permafrost thaw, which mobilizes organic matter.</p><p>Here, we present results of high frequency monitoring program of the Lena River waters in the central part of its delta at the Laptev Sea. For the first time, a number of biogeochemical parameters such as dissolved organic carbon (DOC), coloured dissolved organic matter, electrical conductivity, temperature, and d<sup>18</sup>O isotopes were measured at an interval of every few days throughout the entire season. Currently, the data set comprises two complete years from the spring 2018 until the spring 2020, which were characterized by extremely high and low summer discharges, respectively. While 2018 to 2019 was the fourth highest on record from 1936 to present, resulting in an annual DOC flux of 6.8 Tg C yr<sup>-1</sup>, 2019 was the sixth lowest discharge year with a significantly lower DOC flux of 4.5 Tg C yr<sup>-1</sup>. Endmember analysis using electrical conductivity and d<sup>18</sup>O isotopes showed that rainwater transported less DOC in 2019 (1.5 Tg C) than in 2018 (2.9 Tg C) although the winter base flow and the snow and ice meltwater transported similar amounts.</p><p>The biogeochemical response of the Lena River water provides us with new insights into the catchment processes, including permafrost thaw and potential mobilization of previously frozen organic carbon. Our new monitoring program will serve 1) as a baseline to measure future changes and 2) as a training dataset to project changes under future climate scenarios.</p>

Measurement and Prediction of Sound Exposure Levels by University Wind Bands

2010 ◽  
Vol 25 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Kris Chesky
Keyword(s):  
Linear Regression Analysis ◽  
Critical Role ◽  
Significant Proportion ◽  
Sound Exposure ◽  
Sound Levels ◽  
Wind Bands ◽  
Exposure Levels ◽  
The Mean ◽  
Over Time

The purpose of this study was to determine sound exposure levels generated in two college wind bands. Dosimeter data from a large sample of ensemble-based instructional activities (n = 43) was collected over time and processed to assess associations with predictor variables that may be relevant to this context, including indicators of time spend at various intensity levels, maximum and peak sound levels, degree of variability of sound levels over time, and the percentage of time playing music. The mean dose per event for the entire sample was 109.5% and ranged from 53.8% to 166.9%. Results of linear regression analysis revealed that regressors accounted for a significant proportion of the variance in dose (F = 128.42, p < 0.000) and a statistically significant and very large (96% variance accounted for) contribution to the prediction of dose. Findings implicate the critical role of the instructor and teaching pedagogy.

scholarly journals Towards improving the physical basis for ice-dynamics models

1997 ◽  
Vol 25 ◽  
pp. 177-182 ◽  
Author(s):  
J. A. Richter-Menge
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
The Arctic ◽  
Frequency Content ◽  
Ice Dynamics ◽  
Relative Significance ◽  
Thermally Induced ◽  
Induced Stress ◽  
Dynamics Models

In situ measurements of ice stress were made on a multi-year floe in the Alaskan Beaufort Sea over a 6 month period, beginning in October 1993. The data suggest that, in this region of the Arctic during this experiment, there were two main sources of stress: a thermally induced stress caused by changes in air temperature, and a stress generated by ice motion. Due to the natural damping of the snow and ice above the sensor, the thermally-induced stresses are low frequency (order of days). Stresses associated with periods of ice motion have both a high-frequency (order of hours), and low-frequency, content. The relative significance of these sources of stress is seasonal, reflecting the changes in the strength and continuity of the pack.

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