| 1. |
- Enmar, Linda, et al.
(author)
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A note on ADCP-based indirect observations of turbulence
- 2016
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In: Boreal environment research. - 1239-6095 .- 1797-2469. ; 21:1-2, s. 44-52
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Journal article (peer-reviewed)abstract
- A 70-day data set from bottom-mounted ADCPs on the two sides of the Faroe-Bank Channel was analysed using the recorded flow variance and echo intensity in the deeper reaches of the passage as proxies for turbulence. A consistent picture emerged, not least since the data losses (which were ascribed to turbulence-induced activation of the fish-elimination option in the ADCP software) could be shown to co-vary with the internal M-2 tide affecting the vertical shear, which in turn proved to be correlated with the flow variance.
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| 2. |
- Andersson, Mathias H, et al.
(author)
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A framework for regulating underwater noise during pile driving
- 2017
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Reports (other academic/artistic)abstract
- Pile driving is a common technique used during the construction of bridges, offshore wind power, and underwater infrastructure or shoreline structures. It is the process by which a foundation, beam or pole is hammered or vibrated down into the bottom, which can generate extremely loud noise that propagates throughout the surrounding water and sediment. The noise can reach such high levels that marine animals are at risk of disturbance, injury or even death.Sweden currently lacks established thresholds stating the level at which underwater noise potentially disturbs or injures marine animals. Hence, there are no guidance values for allowable underwater noise levels from noiseproducing activities to avoid serious environmental impacts. Several countries in Europe have defined thresholds for when underwater noise can result in severe negative environmental impacts as well as standards for measuring, analysing and reporting underwater noise levels.The purpose of this study is to review the scientific literature on underwater noise from pile driving and its effects on marine life. The study aims to define the noise levels that can cause injury and other negative effects and, on this basis, recommend noise levels that can be used to establish guidance values for regulating underwater noise for Swedish waters and species. The study presents examples of the factors that contribute to sound propagation in Swedish waters and how this influences the noise level from a pile strike as a function of distance at four study areas along the Swedish coast. Additionally, the study contains a thorough technical description of pile driving activities, basic underwater acoustics and noise effects on marine animals. These effects (injury and behavioral, e.g., flight, but not subtle effects) are demonstrated on representative species such as the harbour porpoise (Phocoena phocoena), Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and on fish larvae and eggs. The study’s authors look atthe original sources of information that other countries base their guidelines and thresholds on, so the recommendations follow scientifically determined levels rather than values that have been rounded off or otherwise altered.The study presents sound levels in three different units, each with different biological relevance to the effects caused by a pile driving activity. None of the sound levels have been frequency weighted for a specific species, as this method is not yet fully established. The first unit used is the sound pressure level SPL(peak), which is the maximum overpressure or underpressure of the noise pulse generated by the pile strike. This unit has a high relevance for behavioural effects. The sound exposure level, SEL, is the calculated energy level over a period of time and expresses the energy of the entire sound pulse. SEL is the unit most related to hearing impairing effects. SEL(ss) is the value for a single strike while SEL(cum) is the cumulative value of a determined number of pulses over a period of time. The review revealed that for Atlantic cod and Atlantic herring there are currently no studies that can be used to determine a species’ specific threshold value for injury, but studies show that loud noise can affect both species negatively. Because of this, the recommended noise levels for injury are based mainly on studies on other species exposed to pile driving noise in laboratory environments, supported by studies conducting large-scale experiments in tanks and oceans. The levels at which fish are at risk of death or sustaining serious injury to internal organs is SPL 207 dB re 1 μPa, SEL(ss) 174 dB re 1 μPa2s and SEL(cum) 204 dB re 1 μPa2s. Note that for injury in fish, the cumulative sound exposure level has higher relevance than the single-strike level as the cited studies found injuries after a certain time period of exposure. The thresholds for fish larvae and eggs are based on the fact that no negative effects were observed at exposures of up to SPL(peak) 217 dB re 1 μPa, SEL(ss) 187 dB re 1 μPa2s and SEL(cum) 207 dB re 1 μPa2s. However, there are relatively few studies on early life stages of fish. There are more species-specific studies on harbour porpoises regarding noise than there are for Atlantic cod and Atlantic herring. Nonetheless, only a few can be used to determine thresholds that will lead to injury or negative behavioural effects. The levels at which there is a risk of a temporary impact on hearing, i.e. temporary threshold shift (TTS), for the harbour porpoises is SPL(peak) 194 dB re 1 μPa, SEL(ss) 164 dB re 1 μPa2s and SEL(cum) 175 dB re 1 μPa2s. When it comes to TTS, the cumulative sound exposure level, SEL(cum), is of primary importance. However, this unit is dependent on a specific time and number of pulses. For permanent threshold shift (PTS), the level is set to SPL(peak) 200 dB re 1 μPa, SEL(ss) 179 dB re 1 μPa2s and SEL(cum) 190 dB re 1 μPa2s. The recommended level should be revised as new relevant studies are conducted.
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| 3. |
- Andersson, Mathias H., et al.
(author)
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Displacement effects of ship noise on fish population : FP7 - Collaborative Project n° 314227 WP 4: Sensitivity of marine life to shipping noise Task 4.2.1
- 2015
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Reports (other academic/artistic)abstract
- Ship induced noise is one of the major contributors to the elevated noise levels in the world’s oceans today. However, the knowledge about the impact on marine organisms is still scarce. Especially the effects on fish behaviour needs to be studied as fish are a fundamental part of the oceans ecosystem. Direct measurement of fish behaviour in the open sea area is technically difficult but needs to be done in order to estimate reaction thresholds and scales of any reaction. This experiment studies the long term behavioural reaction by wild cod (Gadus morhua) to ship noise and describes the character and scale of the reaction. This study took place on the Swedish west coast with a small local cod population and the area is normally without any large vessel traffic. For the ship disturbance, the Swedish Coast Guard ship KBV 032 was hired and passed thru the area nine times during three days. During the three days of ship noise exposure, the noise levels increased well above the ambient noise. The ship signature was what could be expected in terms of spectral level with most radiated noise energy between 100 - 500 Hz. The ship had a higher source level than expected (232 dB re 1μPa at 1 m, 10 - 300 Hz) but this was deliberate as the crew was asked to use the propellers in a non-optimal way to generate as much noise as possible. The result was a lot of broadband cavitation pulses generated by the ship. Then a noise footprint model was created and used in the estimates of received levels (exposure level) by the individual fish in the area based on the most probable location. It was clear in the transmission loss varied between the two sites where at the shallow site, the noise was attenuated more compared to the deep site. This is probably caused by the quite complicated propagation pattern. Also, the acoustically different bottom properties will affect the transmission loss in the area. In total, 39 cod (Gadus morhua) were caught by hand jigging and were fitted with internal acoustical tags. Bottom mounted receivers were deployed covering the area where the cod were known to inhabit. This study was designed to capture more large scale movements of hundreds of meters and not startle responses to the ship noise. Out of the 39 tagged fish, 17 and 18 fish met the set quality criterion for the short time behaviour analysis and 23 fish for long time behaviour to be included in the analysis. Some fish met the quality criteria for both the short and long term analysis. The other fish were either eaten by seals, caught by fishermen, left the area or had a malfunctioning tag. In general, the noticed reaction in terms of horizontal swimming were much smaller than expected and what the study was designed for. This results was surprising as the sound pressure levels the fish were exposed to would, based on the literature, cause a strong behaviour response in the fish. The movement was not in any large scale that would affect their energy consumption and affect their long term survival. This study was able to track fish with an accuracy of less than 10 m and estimates an interval of received noise level. This is one of the first studies of its kind that is tracking free swimming fish over a long period of time during an acoustic disturbance.
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| 4. |
- Andersson, Mathias H., et al.
(author)
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Underlag för reglering av undervattensljud vid pålning
- 2016
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Reports (other academic/artistic)abstract
- Vid byggnation av broar, havsbaserad vindkraft och andra havsbaserade eller strandnära konstruktioner används det oftast någon form av pålningsteknik för att få ner konstruktionen i botten. Detta innebär att ett fundament, balk eller spont hamras eller vibreras ner i botten, vilket kan generera mycket höga ljudnivåer som sprids ut i vattnet och ner i botten. Ljudnivåerna är så höga att marina organismer kan störas, skadas eller till och med dödas. Idag saknar Sverige fastställda ljudnivåer för när undervattensbuller blir så högt att de kan skada djur i havet. Det saknas därför också vedertagna begränsningsvärden som anger vilka nivåer av undervattensbuller som kan tillåtas för bullrande aktiviteter utan att riskera allvarliga miljöeffekter. Flera länder i Europa har någon form av gränsvärden för när bullernivån under vattnet kan ge upphov till allvarlig miljöpåverkan liksom standarder för hur undervattensbuller skall mätas och rapporteras. Syftet med denna studie var att ta fram ett vetenskapligt underlag rörande ljudet från pålning i havet och dess påverkan på det marina livet. Slutmålet var att utifrån den vetenskapliga information som finns idag ge förslag på ljudnivåer för skador och negativ påverkan som sedan kan användas för att ta fram begränsningsvärden för reglering av undervattensbuller anpassade för svenska vatten och arter. Studien ger ett antal exempel på vilka faktorer som påverkar ljudutbredningen i svenska vatten och hur detta påverkar ett pålningsslags ljudnivå som funktion av avstånd i fyra typområden kring den svenska kusten. Vidare presenteras ingående både tekniska beskrivningar av pålningsaktiviteter, undervattensakustik samt påverkan på marina djur. Denna påverkan (skada och flyktbeteende men ej subtila effekter) demonstreras med hjälp av ett antal typarter som tandvalen tumlare (Phocoena phocoena) och fiskarterna torsk (Gadus morhua) och sill (Clupea clupea) samt fiskägg och fisklarver. I denna studie har författarna gått tillbaka till de originalkällor av information som andra länders gränsvärden grundas på, så att rekommendationerna bygger på vetenskapliga nivåer och inte värden som har avrundats eller på annat sätt ändrats.Studien presenterar ljudnivåer i tre olika enheter då dessa har olika biologisk relevans för påverkan från en pålningsaktivitet. Inga av dessa värden har frekvensviktats för att anpassas för en specifik art då denna metod ännu inte är helt vedertagen. Den första enheten är ljudtrycksnivå SPL(topp), d.v.s. det maximala över- eller undertryck som den av pålningsslaget genererade ljudpulsen har. Denna enhet har hög relevans för beteendepåverkan. För ljudexponeringsnivå SEL, beräknas ljudnivån över en viss tid och tar då med energin i hela ljudpulsen. SEL är den enhet som visats vara bäst relaterad till hörselskador. SEL(enkel) är värdet för en enkel puls och för det kumulativa SEL(kum) har antalet pulser under en viss tid summerats.Litteraturstudien på torsk och sill visar att det i dagsläget inte finns några studier som kan användas för att fastställa en artspecifik ljudnivå för skada men litteraturen visar tydligt på att höga bullernivåer kan påverka torsk och sill negativt. Istället baseras de föreslagna nivåerna i huvudsak på studier på andra arter som har exponerats för pålningsljud i laboratoriemiljö med stöd av studier från mer storskaliga experiment i tankar och hav. De nivåer då fisk riskerar att dödas eller få allvarliga skador på inre organ är 207 dB re 1 μPa SPL(topp), 174 dB re 1 μPa2s SEL(enkel) och 204 dB re 1 μPa2s SEL(kum). Notera att för skada på fisk har det kumulativa värdet högre relevans än enkelvärdet för SEL eftersom studier visar att skador uppkommer efter en viss tids exponering. Nivåerna för påverkan på fiskägg och larver grundas i att inga negativa effekter har observerats vid exponering för ljudtryck från pålning upp till 217 dB re 1 μPa SPL(topp), 187 dB re 1 μPa2s SEL(enkel) och 207 dB re 1 μPa2s SEL(kum). Det finns emellertid mycket få studier relaterat till pålningsljud för dessa livsstadier. För tumlare finns det fler artspecifika studier gjorda relaterat till buller än för torsk och sill. Det är dock endast ett fåtal som kan användas för att bestämma ljudnivåer som leder till skada eller negativ beteendepåverkan. De ljudnivåer som riskerar ge tillfällig hörselnedsättning (TTS) hos tumlare är 194 dB re 1 μPa SPL(topp), 164 dB re 1 μPa2s SEL(enkel) och 175 dB re 1 μPa2s SEL(kum). Det är framförallt den kumulativa ljudexponeringsnivån SEL(kum) som har stor betydelse för just TTS, dock hänger detta värde ihop med en specifik tid och antalet pulser vilket kan vara svårt att uppskatta i förväg. Vidare avseende permanent hörselskada (PTS) är ljudnivån 200 dB re 1 μPa SPL(topp), 179 dB re 1 μPa2s SEL(enkel) och 190 dB re 1 μPa2s SEL(kum). Föreslagna nivåer bör uppdateras när nya relevanta forskningsstudier tillkommer.
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| 5. |
- Jalkanen, Jukka-Pekka, et al.
(author)
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Modeling of ships as a source of underwater noise
- 2017
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Conference paper (other academic/artistic)abstract
- Shipping as a source of underwater noise is increasing. Underwater noise emission levels are seldom considered as a ship design parameter unless low vessel noise is specifically required, like in the case of warships and research vessels. Noise emissions are not regulated yet, but the awareness of possible impacts of noise on marine life is increasing. This paper describes the implementation of a noise source model for the Ship Traffic Emission Abatement Model (STEAM; Jalkanen et al. 2009; 2012; Johansson et al, 2017). The combination of vessel technical description and activity can be used to generate noise source maps which are based on actual ship traffic data. The generated noise source maps can ve used to describe the energy emitted as noise to the water, which facilitates regular annual updates of the noise emissions from ship traffic in the Baltic Sea area.
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| 6. |
- Johansson, Kajsa, et al.
(author)
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Stress Response and Habituation to Motorboat Noise in Two Coastal Fish Species in the Bothnian Sea
- 2016
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In: EFFECTS OF NOISE ON AQUATIC LIFE II. - New York, NY : SPRINGER-VERLAG BERLIN. ; 875:875, s. 513-521
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Conference paper (peer-reviewed)abstract
- The effect of motorboat noise on stress responsiveness in Eurasian perch and roach was tested in field enclosure experiments. Perch showed elevated cortisol levels after one 30-min noise exposure but not when exposed to noise repeatedly for 11 days. Roach had higher cortisol levels when exposed to noise than without noise when short- and long-term experiments were pooled. Both species had more cortisol in enclosures with mixed species compared with single-species enclosures. Both species also had higher cortisol levels in the short-term compared with the longterm experiment. Thus, a stress effect of motorboat noise may decrease with time due to habituation.
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| 7. |
- Lidström, Viktor, 1991-, et al.
(author)
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Non-Coherent Acoustic Modulation for Energy Constrained Underwater Platforms
- 2019
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In: OCEANS 2019 - Marseille, OCEANS Marseille 2019. - : Institute of Electrical and Electronics Engineers Inc..
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Conference paper (peer-reviewed)abstract
- With regards to energy constrained Autonomous Underwater Vehicles (AUVs), and difficulties inherent to the acoustic underwater communication channel, a non-coherent method is investigated in order to improve energy consumption and reliability over traditional Frequency Shift Keying (FSK), without increasing the bandwidth. A proposed method of adapting Trellis Coded Modulation (TCM) to constant amplitude Permutated Frequency Shift Keying (PFSK) symbol constellations is evaluated. A system implementation of two PFSK methods is simulated in an Additive White Gaussian Noise channel, and field tested in an underwater channel in the Stockholm archipelago, where a binary FSK reference method is used as a comparison. The main interest is comparing electrical bit energy and bit error rate (BER) for the methods. Time variability of frequency fading, related to wind speed, is also evaluated from the field tests.
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| 8. |
- Magnhagen, Carin, et al.
(author)
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Effects of motorboat noise on foraging behaviour in Eurasian perch and roach : a field experiment
- 2017
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In: Marine Ecology Progress Series. - : INTER-RESEARCH. - 0171-8630 .- 1616-1599. ; 564, s. 115-125
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Journal article (peer-reviewed)abstract
- The negative impact of anthropogenic noise on marine animals is receiving increasing attention. In order to study the effect of motorboat noise on foraging behaviour in fish, we chose 2 species with different hearing abilities. The roach Rutilus rutilus has a better developed sense of hearing than the Eurasian perch Perca fluviatilis. The study took place in an inlet of the Bothnian Sea where boat traffic is almost absent. Groups of 6 fish were placed in field enclosures containing either one of the species or equal numbers of perch and roach. Half of each enclosure was covered with artificial vegetation. The fish were fed with pieces of saithe twice a day, both with and without the disturbance of an outboard motor. Sound pressure level and particle acceleration were measured for the motor, which was run at 2000 rpm. The trials were repeated for 5 d. Perch made fewer feeding attempts during noise exposure compared to controls in the single-species enclosures. As the experiment progressed, they gradually increased feeding and time spent in the open area, both with and without noise, indicating habituation. Habitat utilization was affected by the interaction of noise exposure and day. Roach responded to noise exposure with fewer feeding attempts, higher latency to enter the open area, and longer time spent in the vegetation compared to the controls without noise. Roach behaviour changed with time only when housed together with perch. This study, using authentic sound in a natural habitat, shows that noise exposure may affect the feeding behaviour of fish, that the response is species-specific, and that habituation and the presence of other species may modify the effects.
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| 9. |
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| 10. |
- Nikolopoulos, Anna, et al.
(author)
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BIAS Implementation Plan : Monitoring and assessment guidance for continuous low frequency sound in the Baltic Sea
- 2016
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Reports (other academic/artistic)abstract
- The BIAS Implementation Plan describes a regional programme for monitoring underwater ambient noise in the Baltic Sea. The programme combined measurements and modelling and was successfully implemented in 2012-2016 within the EU LIFE+ project Baltic Sea Information on the Acoustic Soundscape (BIAS) by Sweden, Denmark, Germany, Poland, Estonia and Finland.In 2014, one year of sound measurements was performed at 36 locations with the purpose of establishing the baseline state of ambient noise levels in the Baltic Sea. The measurements, as well as the post-survey processing of the data, were subject to standardized field procedures, quality control and signal processing routines were all developed within BIAS.BIAS dealt exclusively with monitoring continuous low frequency sound as referred to by the Marine Strategy Framework Directive indicator 11.2.1. Therefore, the study focused on the 1/3 octave frequency bands of 63 and 125 Hz, as specified by the indicator, and a third frequency band (2 kHz) which was added to strengthen the ecological relevance of the BIAS results.The measured sound data were used to model the soundscape for the entire project area, providing the first results for the Baltic Sea on a monthly basis. Soundscape maps were produced for the three targeted frequency bands, and three depth intervals: the surface layer (0 to 15m deep), the deep layer (30m to the bottom), and the full water column of the Baltic Sea.A large number of soundscape maps were produced constituting the base for future management of noise in the Baltic Sea. To facilitate an efficient handling of these, and future, results a GIS-based soundscape planning tool was created for visualizing the measured data and the modelled maps in a management friendly concept. BIAS identified two useful statistical measures for characterizing the soundscape which were incorporated into the soundscape planning tool. The year-by-year change of these measures directly relate to the current definition of the indicator.Based on the experiences made in the project, the BIAS implementation plan also outlines a plausible strategy for the future monitoring and the elements needed for maintaining a joint implementation for underwater ambient noise in the Baltic Sea region.
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