28 research outputs found
Acoustique passive et peuplements benthiques avec applications aux Ă©tudes d'impact EMR
Understanding the spatial and temporal dynamics of benthic populations, both natural and induced by anthropogenic pressures, requires new observation methods with high temporal resolution and long periods of measurement. The recording and analysis of sounds produced in the marine environment give access to the soundscape, and in particular to one of its biological components, the benthic biophony. Observing the spatiotemporal variability of this benthic biophony, in order to contribute to the evaluation of the structure, functioning, state and evolution of the benthic compartment, is the main objective of the thesis. To do this we have developed two tools to evaluate the spatial variability of these emissions with one sensor or more. The first is a descriptor of the shape of the spectra of the benthic snaps allowing to better characterize the diversity of benthic biophony. The second is a method of three-dimensional localization of the benthic sound sources and mapping of this biophony for spatial scales ranging from 500 meters to 5 meters. Using these two tools, we have demonstrated the feasibility of benthos monitoring through its biophony at specific sites. In an applicative part, we were interested in sites of production of marine renewable energies and the understanding and observation of their impacts on the marine fauna. On a workshop site of geometry similar to that of an offshore wind farm, we defined, realized and analyzed a proof of concept for the observability of a binary impact: presence or absence of fixed benthic fauna in a sentinel area of a few square meters. The thesis work was concluded by a study measuring the sound level radiated by a tidal current turbine in the energy production phase (Paimpol-BrĂ©hat) and then evaluating the acoustic impacts on three biological compartments: marine mammals, fish and invertebrates.La comprĂ©hension de la dynamique spatiale et temporelle des peuplements benthiques quâelle soit naturelle et induite par des forçages anthropiques, nĂ©cessite de nouvelles mĂ©thodes d'observation du benthos avec des besoins affichĂ©s de haute rĂ©solution temporelle et de longues pĂ©riodes de mesures. L'enregistrement et lâanalyse des sons produits dans lâenvironnement marin donnent accĂšs au paysage acoustique, et notamment Ă lâune de ses composantes biologiques la biophonie benthique. Observer les variabilitĂ©s spatio-temporelles de cette biophonie benthique, afin de contribuer Ă l'Ă©valuation de la structure, du fonctionnement, de lâĂ©tat et des Ă©volutions du compartiment benthique, constitue l'objectif principal de la thĂšse. Pour ce faire nous avons dĂ©veloppĂ© deux outils permettant d'Ă©valuer la variabilitĂ© spatiale de ces Ă©missions avec un ou plusieurs capteurs. Le premier est un descripteur de la forme des spectres des impulsions du benthos permettant de mieux caractĂ©riser la diversitĂ© de la biophonie benthique. Le second est une mĂ©thode de localisation tridimensionnelle des sources sonores benthiques et de cartographie de cette biophonie pour des Ă©chelles spatiales allant de 500 mĂštres jusquâĂ 5 mĂštres. En utilisant ces deux outils, nous avons dĂ©montrĂ© la faisabilitĂ© de l'observation du benthos au travers de sa biophonie sur des sites spĂ©cifiques. Dans une partie applicative, nous nous sommes intĂ©ressĂ©s aux projets de site de production dâĂ©nergies marines renouvelables et Ă la comprĂ©hension et Ă lâobservation de leurs impacts sur la faune marine. Sur un site atelier de gĂ©omĂ©trie similaire Ă celle dâune ferme dâĂ©oliennes offshores, nous avons dĂ©fini, rĂ©alisĂ© et analysĂ© une preuve de concept pour lâobservabilitĂ© dâun effet de type binaire : prĂ©sence ou absence de faune fixĂ©e dans une surface sentinelle de quelques mĂštres carrĂ©. Les travaux de thĂšse ont Ă©tĂ© conclus par une Ă©tude mesurant le niveau sonore rayonnĂ© par une hydrolienne en phase de production dâĂ©nergie (Paimpol-BrĂ©hat) puis Ă©valuant les impacts acoustiques sur trois compartiments biologiques : les mammifĂšres marins, les poissons et les invertĂ©brĂ©s
Passive acoustics and benthic populations with applications to MRE impact assessments
La comprĂ©hension de la dynamique spatiale et temporelle des peuplements benthiques quâelle soit naturelle et induite par des forçages anthropiques, nĂ©cessite de nouvelles mĂ©thodes d'observation du benthos avec des besoins affichĂ©s de haute rĂ©solution temporelle et de longues pĂ©riodes de mesures. L'enregistrement et lâanalyse des sons produits dans lâenvironnement marin donnent accĂšs au paysage acoustique, et notamment Ă lâune de ses composantes biologiques la biophonie benthique. Observer les variabilitĂ©s spatio-temporelles de cette biophonie benthique, afin de contribuer Ă l'Ă©valuation de la structure, du fonctionnement, de lâĂ©tat et des Ă©volutions du compartiment benthique, constitue l'objectif principal de la thĂšse. Pour ce faire nous avons dĂ©veloppĂ© deux outils permettant d'Ă©valuer la variabilitĂ© spatiale de ces Ă©missions avec un ou plusieurs capteurs. Le premier est un descripteur de la forme des spectres des impulsions du benthos permettant de mieux caractĂ©riser la diversitĂ© de la biophonie benthique. Le second est une mĂ©thode de localisation tridimensionnelle des sources sonores benthiques et de cartographie de cette biophonie pour des Ă©chelles spatiales allant de 500 mĂštres jusquâĂ 5 mĂštres. En utilisant ces deux outils, nous avons dĂ©montrĂ© la faisabilitĂ© de l'observation du benthos au travers de sa biophonie sur des sites spĂ©cifiques. Dans une partie applicative, nous nous sommes intĂ©ressĂ©s aux projets de site de production dâĂ©nergies marines renouvelables et Ă la comprĂ©hension et Ă lâobservation de leurs impacts sur la faune marine. Sur un site atelier de gĂ©omĂ©trie similaire Ă celle dâune ferme dâĂ©oliennes offshores, nous avons dĂ©fini, rĂ©alisĂ© et analysĂ© une preuve de concept pour lâobservabilitĂ© dâun effet de type binaire : prĂ©sence ou absence de faune fixĂ©e dans une surface sentinelle de quelques mĂštres carrĂ©. Les travaux de thĂšse ont Ă©tĂ© conclus par une Ă©tude mesurant le niveau sonore rayonnĂ© par une hydrolienne en phase de production dâĂ©nergie (Paimpol-BrĂ©hat) puis Ă©valuant les impacts acoustiques sur trois compartiments biologiques : les mammifĂšres marins, les poissons et les invertĂ©brĂ©s.Understanding the spatial and temporal dynamics of benthic populations, both natural and induced by anthropogenic pressures, requires new observation methods with high temporal resolution and long periods of measurement. The recording and analysis of sounds produced in the marine environment give access to the soundscape, and in particular to one of its biological components, the benthic biophony. Observing the spatiotemporal variability of this benthic biophony, in order to contribute to the evaluation of the structure, functioning, state and evolution of the benthic compartment, is the main objective of the thesis. To do this we have developed two tools to evaluate the spatial variability of these emissions with one sensor or more. The first is a descriptor of the shape of the spectra of the benthic snaps allowing to better characterize the diversity of benthic biophony. The second is a method of three-dimensional localization of the benthic sound sources and mapping of this biophony for spatial scales ranging from 500 meters to 5 meters. Using these two tools, we have demonstrated the feasibility of benthos monitoring through its biophony at specific sites. In an applicative part, we were interested in sites of production of marine renewable energies and the understanding and observation of their impacts on the marine fauna. On a workshop site of geometry similar to that of an offshore wind farm, we defined, realized and analyzed a proof of concept for the observability of a binary impact: presence or absence of fixed benthic fauna in a sentinel area of a few square meters. The thesis work was concluded by a study measuring the sound level radiated by a tidal current turbine in the energy production phase (Paimpol-BrĂ©hat) and then evaluating the acoustic impacts on three biological compartments: marine mammals, fish and invertebrates
Raw acoustic data
10 min recording samples of each of the two maerl beds (fished and unfished
Data from: Marine soundscape shaped by fishing activity
Marine communities face anthropogenic pressures that degrade ecosystems. Because underwater soundscapes carry information about habitat quality, we explored whether destructive impacts of fishing could be evaluated via the soundscape. Maerl beds are recognized as biodiversity hotspots and they experience major worldwide degradation owing to fishing. We collected field acoustic recordings in maerl beds exposed to different fishing practices. We found that unfished maerl beds were threefold louder and exhibited sound frequencies more diversified than those recorded in fished maerl beds. Analyses of associated fauna samples indicated that snapping shrimps provided a major contribution to the maerl bed soundscape. Moreover, sea urchins and squat lobsters most likely contributed to differences between the soundscapes of unfished and fished maerl beds. Our results supported the idea that the soundscape can provide valuable information on maerl bed ecosystem health related to fishing activity
Marine soundscape shaped by fishing activity
International audienceMarine communities face anthropogenic pressures that degrade ecosystems. Because underwater soundscapes carry information about habitat quality, we explored whether destructive impacts of fishing could be evaluated via the soundscape. Maerl beds are recognized as biodiversity hotspots and they experience major worldwide degradation owing to fishing. We collected field acoustic recordings in maerl beds exposed to different fishing practices. We found that unfished maerl beds were threefold louder and exhibited sound frequencies more diversified than those recorded in fished maerl beds. Analyses of associated fauna samples indicated that snapping shrimps provided a major contribution to the maerl bed soundscape. Moreover, sea urchins and squat lobsters most likely contributed to differences between the soundscapes of unfished and fished maerl beds. Our results supported the idea that the soundscape can provide valuable information on maerl bed ecosystem health related to fishing activity
Marine soundscape shaped by fishing activity
International audienceMarine communities face anthropogenic pressures that degrade ecosystems. Because underwater soundscapes carry information about habitat quality, we explored whether destructive impacts of fishing could be evaluated via the soundscape. Maerl beds are recognized as biodiversity hotspots and they experience major worldwide degradation owing to fishing. We collected field acoustic recordings in maerl beds exposed to different fishing practices. We found that unfished maerl beds were threefold louder and exhibited sound frequencies more diversified than those recorded in fished maerl beds. Analyses of associated fauna samples indicated that snapping shrimps provided a major contribution to the maerl bed soundscape. Moreover, sea urchins and squat lobsters most likely contributed to differences between the soundscapes of unfished and fished maerl beds. Our results supported the idea that the soundscape can provide valuable information on maerl bed ecosystem health related to fishing activity
Cartographie de la biophonie des Ă©cosystĂšmes cĂŽtiers
1922 segments de 10 secondes de mesures sonores ont Ă©tĂ© enregistrĂ©s dans une zone de 4 kmÂČ comprise entre le trait de cĂŽte et lâisobathe 50 m Ă la pointe de la Revelatta (Calvi, Corse). Nous caractĂ©risons le paysage acoustique de cette zone complexe qui prĂ©sente 4 habitats (roche, herbier, sable et coralligĂšne) entrelacĂ©s. Le SPL calculĂ© sur la bande biophonique [2 kHz, 40 kHz] est maximum sur la frange rocheuse et dĂ©croĂźt vers le large en suivant la rĂ©gression SPL (Sound pressure Level, dB re. 1ÎŒPa) = 147 â 14log10(r) oĂč r est la distance Ă la cĂŽte. Ce modĂšle de rĂ©gression sâappuyant sur des considĂ©rations Ă©nergĂ©tiques uniquement laisse penser que les Ă©missions sonores de la roche sont fortes et quâelles se propagent vers les autres habitats dont les biophonies ne seraient que des captations de celle de la roche. Pour Ă©valuer la validitĂ© de cette hypothĂšse, nous avons Ă©tudiĂ© la diversitĂ© des formes spectrales mesurĂ©es. Pour cela, nous avons calculĂ© une analyse en composantes principales (ACP) des 2 millions de spectres collectĂ©s. Les deux premiĂšres valeurs propres de lâACP rĂ©sument plus de 50 % de la variabilitĂ© totale des spectres et 80 % de la variabilitĂ© de la forme des impulsions. Les scores 1 et 2 de lâACP forment un nuage continu que nous avons segmentĂ© en 4 familles en fonction du quadrant du plan {score 1, score 2} auquel ils appartiennent. Ces 4 familles dĂ©finissent 3 signatures spectrales de la biophonie du site Ă©tudiĂ© (les signatures des quadrants 1 et 2 Ă©tant proches) : des impulsions prĂ©sentant un maximum marquĂ© vers 3 et 4 kHz, des impulsions prĂ©sentant une bosse entre 5 et 12 kHz, des impulsions prĂ©sentant un maximum haute frĂ©quence au-delĂ de 20 kHz. Les 4 proportions des impulsions gĂ©nĂ©rĂ©es par un habitat dans les quatre quadrants du plan {score 1, score 2} de lâACP sont proposĂ©es comme descripteur de la diversitĂ© des formes spectrales de la biophonie dâun habitat. Ă partir de ce quadruplet de descripteurs, nous avons pu affiner la description du paysage acoustique, bĂąti initialement sur des considĂ©rations Ă©nergĂ©tiques. Les signatures spectrales des 4 habitats sont constituĂ©es des mĂȘmes quatre ingrĂ©dients mais dans des proportions diffĂ©rentes. Le coralligĂšne possĂšde une biophonie spĂ©cifique diffĂ©rente des autres habitats et cette biophonie est crĂ©Ă©e par des impulsions hautes frĂ©quences Ă©mises au sein du coralligĂšne. La roche prĂ©sente une production sonore forte avec une grande proportion dâimpulsions basses frĂ©quences autour de 3 Ă 4 KHz. Lâherbier et le sable ne produisent pas ou peu dâimpulsions, lâherbier Ă©coute la production sonore de la roche alors que le sable Ă©coute celles de la roche et du coralligĂšne.1922 10s-long snapshots of sounds have been measured in a small 4km2 coastal area (depth from 0 m to 50 m) near the pointe of Revelatta, (Calvi, Corse). Our aim is to build the soundscape of this complex area hosting 4 interleaved habitats (rocks, seagrass, sand, coralligenous). Wide Band [2 kHz, 40 kHz] SPL is maximum at the rocks and decrease offshore with the regression law: SPL (dB re.1ÎŒPa) = 147 â 14log10(r) with r the distance to the coastline. The range of detection of the biophony of the rocks extends from 1800m to 8300m. This regression law based on energetic criteria only allows to think that the biophony of the rocks is loud and propagates to the others habitats. We assess the diversity of the spectral shape of the biophony by computing the PCA of 2 million of measured spectra. The two first eigenvalues explain 50% of the spectral variability. The spectra and their scores 1 and 2 create a continuous cloud in {score 1, score 2} plan. Then, we propose to segment the data in 4 quadrants depending of the sign of score 1 and score 2 of the PCA. Each quadrant produces a family of spectral signatures (spectrum with high peak at 3 kHz and 4 KHz, spectrum with wide bump between 5 kHz and 12 kHz, spectrum with maximum at high frequency more than 20 kHz). The 4 proportions of impulses from a given habitat in each of the 4 quadrants are proposed to describe the diversity of spectrum shape of this habitat. For our data base, each habitat hosted the four families of spectral signature but with different proportions. The coralligenous hosts its own sound production with high frequency impulses. The rocks hosts its own sound production with low frequency impulses. Seagrass habitats listen to the rocks and sand habitats listen to the rocks and the coralligenous
Underwater operational noise level emitted by a tidal current turbine and its potential impact on marine fauna
International audienc
Biogeography of acoustic biodiversity of NW Mediterranean coralligenous reefs
WOS:000687326500015International audienceMonitoring the biodiversity of key habitats and understanding the drivers across spatial scales is essential for preserving ecosystem functions and associated services. Coralligenous reefs are threatened marine biodiversity hotspots that are challenging to monitor. As fish sounds reflect biodiversity in other habitats, we unveiled the biogeography of coralligenous reef sounds across the north-western Mediterranean using data from 27 sites covering 2000 km and 3 regions over a 3-year period. We assessed how acoustic biodiversity is related to habitat parameters and environmental status. We identified 28 putative fish sound types, which is up to four times as many as recorded in other Mediterranean habitats. 40% of these sounds are not found in other coastal habitats, thus strongly related to coralligenous reefs. Acoustic diversity differed between geographical regions. Ubiquitous sound types were identified, including sounds from top-predator species and others that were more specifically related to the presence of ecosystem engineers (red coral, gorgonians), which are key players in maintaining habitat function. The main determinants of acoustic community composition were depth and percentage coverage of coralligenous outcrops, suggesting that fish-related acoustic communities exhibit bathymetric stratification and are related to benthic reef assemblages. Multivariate analysis also revealed that acoustic communities can reflect different environmental states. This study presents the first large-scale map of acoustic fish biodiversity providing insights into the ichthyofauna that is otherwise difficult to assess because of reduced diving times. It also highlights the potential of passive acoustics in providing new aspects of the correlates of biogeographical patterns of this emblematic habitat relevant for monitoring and conservation