Coral reef & temperate coastal soundscape features evident in directional and omnidirectional passive acoustic time series

IntroductionProject CAELUS is developing the United Kingdom's first national distribution network using drones to transport vital medical supplies throughout Scotland. Noise is a major barrier to public acceptance of drone networks, yet empirical data on the human response to drones used in a medical delivery context remains limited. This study addresses that gap by investigating the annoyance response to sounds from the eVTOL medical delivery drone used in Project CAELUS.MethodsAn online listening experiment was conducted to assess annoyance related to overflight (N – 425) and take-off (N – 278) operations. The experiment examined the effects of listener–drone distance, ambient soundscape (remote rural, rural village, urban), and contextual framing (medical delivery vs. no context) on annoyance. Data were analysed using aligned rank transform ANOVAs to test for main effects and interactions for each factor.ResultsAligned rank transform ANOVAs revealed significant effects of listener–drone distance, ambient soundscape, and contextual framing on annoyance (p < 0.01 for all three factors). Annoyance decreased with increasing distance from the drone and was higher in quieter ambient soundscapes. Providing contextual information about the medical use of the drone significantly reduced annoyance.DiscussionFindings indicate that both acoustic and non-acoustic factors influence perceived annoyance from drone operations. In particular, contextual information about medical use reduced annoyance, suggesting that effective community engagement may improve public acceptance of drone networks.

We describe a method for notifying users through auditory cues embedded in an ambient soundscape in the environment. It uses pieces of music which are composed in such a way, that particular instruments or motifs can be added or omitted without losing the aesthetic quality of the overall composition. This allows for very subtle modifications in the soundscape which are only noticed by those users who have chosen this particular instrument or motif as their notification instrument before. As a side effect, the soundscape itself can be used to subtly influence the mood of users. The method has been implemented in a prototype, which we briefly discuss. The prototype is implemented using a spatial audio framework and can hence notify users from particular directions.

Traditional auditory perceptual models for detection of complex signals against complex ambient soundscapes are based on the human audibility threshold imposed upon computed representations of auditory critical band filters. Such models attempt to locate a positive signal‐to‐noise ratio in any critical band and then apply classic signal detection theory to derive detectability measures (d′) and probability of detection values for the event. One limitation to these models is the limited experimental validation against human sound jury performance, especially using very low‐frequency target signals such as helicopters. This study compares computational auditory detection model predictions against a corresponding large sample of human sound jury data points obtained in the laboratory. Helicopter and ambient soundscape signals were obtained from high‐sensitivity recordings in the field. Playback in the laboratory was achieved under high‐fidelity headphones calibrated to accommodate helicopter primary rotor frequencies with minimal distortion above human sensation level. All listeners completed at least 12 000 trials detecting helicopters against rural and urban soundscapes to represent the spectrum of potential environments involved in a real world scenario. Analysis compares the human sound jury performance against a contemporary computational auditory detection model, called “AUDIB,” developed by the U.S. Army and NASA.

The use of hyperspectral imaging in marine applications is limited, largely due to the cost-prohibitive nature of the technology and the risk of submerging such expensive electronics. Here, we examine the use of low-cost (<5000 GBP) hyperspectral imaging as a potential addition to the marine monitoring toolbox. Using coral reefs in Bermuda as a case study and a trial for the technology, data was collected across two reef morphologies, representing fringing reefs and patch reefs. Hyperspectral data of various coral species, Montastraea cavernosa, Diploria labyrinthiformis, Pseudodiploria strigosa, and Plexaurella sp., were successfully captured and analyzed, indicating the practicality and suitability of underwater hyperspectral imaging for use in coral reef assessment. The spectral data was also used to demonstrate simple spectral classification to provide values of the percentage coverage of benthic habitat types. Finally, the raw image data was used to generate digital elevation models to measure the physical structure of corals, providing another data type able to be used in reef assessments. Future improvements were also suggested regarding how to improve the spectral data captured by the technique to account for the accurate application of correction algorithms.

The unique marine ecosystems of coral reefs express varying levels of degradation as a result of increasing anthropogenic pressures. This is the main reason why more than 200 coral reef localities were proclaimed as natural reserves or marine parks under varying legislation, rules, and monitoring and management programs. Ironically, the conventional management plans increased accessibility to many reef localities and enhanced dramatically the impact of tourism on reef habitats. Recreational activities including SCUBA and skin diving, fishing, human trampling, sediment re‐suspension, and other damage caused by “innocent” visitors are causing a rapid deterioration of many reefs. Their destruction requires years and decades for full recovery. I propose to rehabilitate such damaged habitats by the alternate strategy of “gardening coral reefs” with asexual and sexual recruits. Coral branches, colony fragments, and whole small colonies (asexual recruits) and laboratory or in situ settled planula‐larvae (sexual recruits) are designed to be transplanted into denuded reefs for restoration. This approach is further improved when the sexual and asexual recruits are maricultured in situ within special protected areas, before being transplanted. The use of sexual recruits ensures an increase in genetic diversity. I discuss several methodologies and results already accumulated showing the applicability of this gardening strategy for rehabilitation of denuded coral reefs. This restoration strategy should be integrated with proper management similar to that of already established reforestation in terrestrial habitats. The best candidates for employing this strategy are the fast‐growing coral species, usually branching forms and species that brood their planulae larvae.

In marine ecology research, it is crucial to accurately identify the marine mammal species active in the target area during the current season, which helps researchers understand the behavioral patterns of different species and their ecological environment. However, the difficulty and high cost of collecting marine mammal calls, coupled with limited publicly available datasets, result in insufficient data for support, making it difficult to obtain accurate and reliable identification results. To address this problem, we propose MarGEN, a deep learning-based augmentation method for marine mammal call signal data. This method processed the call data into Mel spectrograms, then designed a self-attention conditional generative adversarial network to generate new samples of Mel spectrograms that were highly similar to the real data, and finally reconstructed them into call signals using WaveGlow. The classification experiments on the calls of four Marine mammals show that MarGEN significantly enriches the diversity and volume of the data, increasing the classification accuracy of the model by an average of 4.7%. The method proposed in this paper greatly promotes marine ecological protection and sustainable development, while effectively advancing research progress in bionic covert underwater acoustic communication technology.

The purpose of this review is to provide an historic record of the author’s experience from the 1960s through the 1990s with coral reefs and the impacts of land-based pollution and other actions by man on this important ecosystem, from the islands of the Caribbean and Central America to the West/East Coasts of Africa and the Western Indian Ocean. This is tied into the concept of Community Based Natural Resource Management (CBNRM), its origins in Southern Africa tied to Africa’s mega-fauna and how it can apply to fisher communities in the tropics. It concludes that unless human population pressures and the current forms of “development and conservation” both linked to pollution and habitat degradation are addressed, the future for both man and these unique ecosystems are in jeopardy. A key to this solution is how the Developed World relates to the Developing World. It is hoped that this review will provide insight to future generations of ecologists, researchers, resource managers, politicians donors and NGOs (non- governmental organizations) as to the issues they will confront if both mankind and nature are to have a viable future, living in harmony. Currently, they appear to be in conflict with each other and only man can resolve these issues based upon how he interacts with Mother Nature.

Coral reefs are unique marine ecosystems that form huge morphological structures (frameworks) in today’s oceans. These include coral islands (atolls), barrier reefs, and fringing reefs that form the most impressive products of CaCO3 biomineralization. The framework builders are mainly hermatypic corals, calcareous algae, foraminifera, and mollusks that together are responsible for almost 50% of the net annual CaCO3 precipitation in the oceans. The reef ecosystem acts as a huge filtration system that extracts plankton from the vast fluxes of ocean water that flow through the framework. The existence of these wave resistant structures in spite of chemical, biological, and physical erosion depends on their exceedingly high rates of calcification. Coral mortality due to bleaching (caused by global warming) and ocean acidification caused by atmospheric CO2 increase are now the major threats to the existence of these unique ecosystems. When the rates of dissolution and erosion become higher than the rates of precipitation, the entire coral ecosystem starts to collapse and will eventually be reduced to piles of rubble while its magnificent and high diversity fauna will vanish. The loss to nature and to humanity would be unprecedented and it may occur within the next 50 years. In this chapter, we discuss the issue of ocean acidification and its major effects of corals from the cell level to the reef communities. Based on the recently published literature, it can be generalized that calcification in corals is strongly reduced when seawater become slightly acidified. Ocean acidification lowers both the pH and the CO 3 2− ion concentration in the surface ocean, but calcification at the organism level responds mainly to CO 3 2− and not to pH. Most reports show that the symbiotic algae are not sensitive to changes in the carbonate chemistry. The potential mechanisms responsible for coral sensitivity to acidification are either direct input of seawater to the biomineralization site or high sensitivity of the enzymes involved in calcification to pH and/or CO2 concentrations. Increase in pH at the biomineralization site is most probably the most energy demanding process that is influenced by ocean acidification. While hermatypic corals and other calcifiers reduce their rates of calcification, chemical and biological dissolution increase and hence net calcification of the entire coral reef is decreasing dramatically. Community metabolism in several sites and in field enclosures show in some cases net dissolution. Using the relations between aragonite saturation (Ωarag) and community calcification, it is possible to predict that coral reefs globally may start to dissolve when atmospheric CO2 doubles.

Coral reefs are unique, complex and high-productivity marine ecosystems that make coral reefs a place to grow and breed most fish and biota in the waters, and physically the function of coral reefs is to withstand coastal abrasion, break waves and so on. To be able to manage coral reefs properly, valid data support is needed as a basis for formulating a policy. Gili Labak Island is one of the islands that is currently a tourist attraction because it has a very wide expanse of coral reefs. The UPT method is a method that utilizes technological developments, because in this method digital camera technology and computer software are used. Data retrieval in the form of underwater photos is done by shooting using an underwater digital camera. The photographs were then analyzed using computer software to obtain quantitative data. This study aims to calculate the biota in the transect. The results obtained Coral 72.92%, Dead coral (DC) 2.03, Dead Coral Algae (DCA) 9.09%, Soft Coral (SC) 0.33%, Rubble (R) 6.15%, Sand (S) 8.98%, Rock (RK) 0.52%.

Background Marine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies. Methods Within the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites. Results SPL were different by site, time (day vs. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (Ophidion spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.

Stationary compact arrays of synchronized hydrophones are an efficient tool to evaluate the azimuth and elevation angles and positions of marine mammals, vessels, and other sources that produce detectable sounds. A compact array designed by JASCO Applied Sciences (Canada) Ltd., was used to estimate the azimuth and elevation angles of ship noise and marine mammal calls and to estimate positions and to track sources from bearing only measurements provided by both single and multiple arrays. Array performance was tested with various sources that transmitted impulsive and continuous sounds; GPS coordinates were known for all sources. Bearing and position accuracy as functions of sound bandwidth, duration, and other parameters, were estimated. Test results demonstrated that the array’s accuracy came close to the Cramér-Rao bounds. In in situ tests, correlated bearing errors were observed. Refraction, surface and bottom reflections and other unpredictable sound propagation effects caused most of the bearing errors. The source position and heading angle estimation accuracy was evaluated using the array deployed in the Strait of Georgia, BC, Canada. Test results demonstrated that the array can provide the highest possible accuracy and can be used in various applications involving long-term passive acoustic monitoring of large areas.

Deep clustering was applied to unlabeled, automatically detected signals in a coral reef soundscape to distinguish fish pulse calls from segments of whale song. Deep embedded clustering (DEC) learned latent features of the signals and formed clusters using fixed-length power spectrograms of the signals. Handpicked spectral and temporal features were also extracted and clustered with Gaussian mixture models (GMM) and conventional clustering. DEC, GMM, and conventional clustering were tested on simulated datasets of fish pulse calls and whale song units with randomized bandwidth, duration, and SNR. Both GMM and DEC achieved high accuracy and identified clusters with fish calls, whale song units, and simultaneous fish calls and whale song units. Conventional clustering methods K-means and hierarchical agglomerative clustering had low accuracy in scenarios with unequally sized clusters or multiple signals. Experimentally detected fish pulse calls and whale song units recorded near Hawaii in February–March 2020 were clustered with DEC, GMM, and conventional clustering. DEC demonstrated the highest accuracy on a small, manually labeled dataset and successfully separated clusters of fish calls and whale song units. GMM achieved high recall for detecting whale song units but accuracy. Both GMM and DEC overpredicted the number of whale song unit signals.

Plastic pollution has emerged as one of the most pervasive and ecologically disruptive anthropogenic stressors confronting aquatic ecosystems in the twenty-first century. The present review synthesizes evidence from peer-reviewed literature on the sources, transport pathways, and biological impacts of macro- and microplastic contamination across marine, freshwater, and coastal environments. Physical interactions including ingestion and entanglement inflict direct physiological harm on taxonomically diverse organisms such as fish, sea turtles, seabirds, and marine mammals, manifesting as internal injuries, impaired feeding, compromised reproduction, and mortality. Microplastics (< 5 mm) present additional sublethal hazards by functioning as vectors for persistent organic pollutants and heavy metals, facilitating bioaccumulation and trophic transfer through food webs. Soil-dwelling fauna, including earthworms and nematodes, are similarly affected, with cascading consequences for nutrient cycling and edaphic biodiversity. At the ecosystem level, plastic pollution reduces species richness, degrades critical habitats such as coral reefs and mangroves, and undermines the provisioning of essential ecosystem services. The contamination of aquatic food chains further raises concern for human health via dietary exposure. Effective mitigation requires concerted international policy action, enhancement of waste management infrastructure, reduction of single-use plastic consumption, and sustained investment in biodegradable material alternatives.

Brazil has performed an important role in the oil and gas industry mainly because the offshore E&P activities in Campos Basin, characterized by deep waters far away from the coast and its sensitive areas. However other basins have increased their importance in the E&P industry where some operations are located very close to the shore in shallow waters with a remarkable environmental sensitivity. Because of this, a new approach has been adopted by Brazilian Federal Environmental Agency (IBAMA) - firstly regarding oil spill preparedness and lately concerning environmental risk assessment. Risk analysis used to be developed as a preliminary hazard analysis (PHA) part of the environmental impact statement that operators (oil companies) have to perform in order to obtain a permit to operate. The main feature of this PHA was the qualitative and subjective risk assessment taking into account only the oil spill amount, in spite of the area sensitivity. Once the operations in those high sensitivity areas have potentially increased, IBAMA has developed a particular Term of Reference regarding the oil spill risk calculation for valued environmental resources such as marine mammals, sea turtles, fishes, etc as well as ecosystems (for example, coral reefs and mangroves). According to the new approach the environmental risk assessment regards to the recovery time of any valued environmental resource that could be affected by oil spill in comparison with the leakage occurrence time. The oil spill risk related to a valued environmental resource is calculated by the product of the release frequency and the environmental consequences based on exposure probability. This paper discusses this new approach adopted in Brazil, involving a quantitative method for the environmental risk assessment of Brazilian Offshore E&P.

Mitigating damaging behaviors of snorkelers to coral reefs in Puerto Rico through a pre-trip media-based intervention