LIstening to the Deep Ocean environment
The sea environment is filled with natural and biological sounds, although increasingly many anthropogenic sources have contributed to the general noise budget of the oceans. The extent to which sound in the sea impacts and affects marine life is a topic of considerable current interest both to the scientific community and to the general public. Scientific interest arises from a need to understand more about the role of sound production and reception in the behaviour, physiology, and ecology of marine organisms. Anthropogenic sound, including sound necessary to study the marine environment, can interfere with the natural use of sound by marine organisms. Public interest arises primarily from the potential effects of anthropogenic sound on marine mammals, given the broad recognition of the importance of sound in the lives of these species. For acoustical oceanographers, marine seismologists, and minerals explorers, sound is the most powerful remote-sensing tool available to determine the geological structure of the seabed and to discover oil and gas reserves deep below the seafloor. Society as a whole has reaped substantial intellectual and practical benefits from these activities, including bottom-mapping sonar and technology leading to the discovery of substantial offshore oil reserves. Scientists and the public are also acutely aware that sound is a primary means by which many marine organisms learn about their environment and that sound is also the primary means of communicating, navigating, and foraging for many species of marine mammals and fish. Indeed, the study of sounds of marine organisms provides insight into important aspects of their biology and helps managing the marine ecosystem environment. Amongst other sources of data, this study allows a better assessment the dynamics of deep-sea community structures (i.e. species composition); the influence of a spatially and temporally variable food supply; the vertical and lateral movements of deep-sea animals, especially cetacean species like the sperm whale, beaked and baleen whales as well as dolphins; the importance of these movements in the transport of nutrients from deep-sea animals; the temporal and spatial influences of natural perturbations on deep-sea communities; the anthropogenic effects on deep-sea cetacean communities; and the long term tracking and monitoring of noise interactions between natural and artificial sources. Discover the dedicated web site http://www.listentothedeep.com/.
Key questions can be considered to be essential to achieve the ESONET objectives, and to evaluate the human and natural contributions to ocean noise:
- to concentrate in one location through ESONET NoE existing data on man-made sources and noise in European waters;
- to develop quantitative relationships between man-made noise and levels of human activity;
- to establish a long-term ocean noise monitoring program covering the frequency band from 1 to 100,000 Hz;
- to conduct research on the distribution, migration patterns, characteristics, identification and classification of marine biological sounds and organisms, in particular Cetaceans pecies (sperm, beaked, baleen whales);
- to long term monitor ocean noise in geographically diverse areas with emphasis on marine mammal habitats;
- to examine the impact of ocean noise on non mammalian species in the marine ecosystem;
- to propose a mandate to the ESONET NoE to coordinate at European level the ocean noise monitoring and research and its effects of noise on the marine ecosystem.
The design and implementation of research on the effects and control of man-made noise in the marine environment must be an interdisciplinary enterprise. Contributions and expertise are needed from electronics experts on the choice and calibration of transducers for monitoring natural, biological and anthropogenic sound sources, from physical acousticians to process signal/information provided by the ESONET NoE, from marine biologists to identify species sound-related behaviour and seasonality and large scale data, from psychoacousticians to assess species related hearing sensitivities and from statisticians for the initial design, data analysis and presentation.
THE LIDO DATA MANAGEMENT ARCHITECTURE
Real-Time streaming server
Task: audio streaming server that will pick up one channel from the recorded data, at the original sampling rate, resample it suitable for internet streaming, and offer it to visitors (with ca. 20 minute delay). There should be a way to limit the number of listeners, control could go through the website running from the LAB, but that may not be necessary.
Task: receiving the 4-channel raw audio input, the data needs to be analysed (in for example 30 second segments) and put in one of the following classes :
- normal ambient noise: discard the data
- boat noise, unusual ambient noise: keep 1 channel, downsample based on frequency content and send to processing server
- cetacean signals, keep all 4 channels, downsample based on frequency content and send to processing server
All data that is send to the processing server is also send to a storage unit.
Temporary storage unit
Task: accept data from the pre-processing server and store it on disk. This server is expected to store a maximum of 1 week of data. At fixed time intervals (likely at night) data will be moved to the LAB permanent storage unit. The software for this needs to be able to handle possible connection problems, and automatically select pending data that needs to be transferred and remove data that already has been sent.
Real-Time analysis server
Task: data will be analysed in blocks of for example 30 seconds; some tasks on this server can be processed in parallel, and if time becomes a constraint several of these blocks can be processed in parallel, on different machines. Software needs to be written to handle the data flow and parallelisation of the processing. The analysis results are send to the LAB, software will need to be able to handle connection problems (temporarily store results until the connection is good again).
- estimation of sound pressure levels (separated for normal ambient noise and the additional signal(s) found)
- identification and tracking of boats
- identification and tracking of cetaceans
- localisation and tracking of impulse signals
Non RT-Processing server at the LAB
Task: the server will
- receive the data analysis results in real-time and store them in a database.
- download the interesting data from the remote temporary storage unit at fixed time intervals
- perform post processing on larger segments data, not in real time. For example, it will create statistical summaries of shipping/cetacean activity during the day/week/month/etc.
Permanent storage unit
Task: permanently store interesting data and analysis results.
Task: Give real-time (with 20 minute delay) and historic analysis results and general information about the project, noise, etc. to visitors; possibly authorise visitors to connect to the real-time data stream; permit registered users to download the interesting data at good quality.
Laboratori d'Aplicacions Bioacustiques, Universitat Politécnica de Catalunya
Avda. Rambla Exposició s/n, 08800 Vilanova i la Geltrú, Barcelona, España.
tel. (34) 93 896 72 27,
fax. (34) 93 896 72 01, email@example.com ,