OPUS - The Open Portal to Underwater Soundscapes


OPUS features two main views to access (the MAP VIEW) and display (the SPECTROGRAM VIEW) data from passive acoustic recordings.  Each view comprises several tabs, which are described hereinafter.
Start exploring selected sounds from the polar oceans by downloading the following list of starter events to your computer and importing it to OPUS either on the MAP VIEW or the SPECTRORAM view:
Starter sounds
Please note that OPUS is tested for use with Firefox, Edge and Chrome.

Selecting recordings in MAP VIEW

In MAP VIEW, information on PAM (passive acoustic monitoring) recordings accessible through OPUS are displayed in the Map tab as green or blue dots with white numbers.  Note that the map as shown initially might not display any recorders when accessible recorders are located outside the spatial range of the map’s initial range.  In this case (or anytime), use the mouse’s wheel to zoom in or out of the map or right click and drag your mouse to pan the map.  Choose the Map Projection button to toggle between Mercator and North/South stereographic projections of the Earth.

Users may constrain displayed recorders according to their data provider or deployment ID by entering the desired information into the free-text fields under FILTER BY DATA PROVIDER and FILTER BY DEPLYOMENT ID, respectively. Recorders may also be filtered according to their deployment periods by making appropriate choices in the TIME FILTERtab.  Other criteria of selection (for example, sample rate, recorder depth and calibration quality) are in planning, but not implemented as of now.

Green dots labelled 1 represent a single passive acoustic data set at this location, blue dots labelled >1 indicate that multiple data sets may be found at this location. Zoom in or click it to separate the underlying recorders.  Hovering over a green dot pops basic information on the selected recorder.

Clicking to a recorder (green dot labelled 1) opens the SPECTROGRAM VIEW in which the acoustic data is displayed, see next section for details

Advanced users might want to use the Event Management tab at the bottom of the screen to load an Event List.  An example Event List was is provided with your invitation to OPUS.   The Event Lists provide an easy way of saving events of interest for your own use in later OPUS sessions or for exchange with others.  Double clicking into the first column of an event will open the SPECTROGRAM VIEW at exactly this event in the respective data set.

Please note the Copyright and Legal Notices tabs in the right column of the MAP VIEW

Browsing recordings in SPECTROGRAM view


·         The Spectrogram tab, an interactive area displaying a stack of nested spectrograms using a fixed colormap as indicated by the colorbars to their right

·         On the top of the right sidebar, a miniature map, indicating which recorder is currently selected and a button to return to the recorder selection on the map view

·         In the middle of the right sidebar, the Audio Control tab to play audio files

·         Below the Audio Control tab the Product Download tab which can be expanded by clicking on the arrow to its right. Here, users have the option to download the current (as determined by marker position) spectrograms and the associated audio file

·         On the bottom of the right sidebar the Recorder Metadata tab, displaying a subset of the recorder’s metadata

·         The Event Management tab at the bottom

PAM data of the selected recorder is presented in the Spectrogram tab in form of a stack of temporally nested spectrograms (annual, monthly, daily, hourly, 10-min (and 2-min in future releases), allowing the user to select any point in time (data permitting) by clicking into any of the spectrograms. OPUS responds by centring the stack of spectrograms around the selected time. 


Users may listen to the corresponding sound files by clicking the PLAY button in the sidebar’s Audio Control tab.  The gain control allows hearing even rather quiet recordings (though use of headphones or external speaker system is highly recommended to hear < 100Hz sounds). The speed control enables to speed up the playback, allowing the users to hear otherwise inaudible, low-frequency sounds.   Playback progress is matched by all spectrograms moving to the left, albeit at different speeds, with the current playback time indicated in each spectrogram by the white central line.  Please note, that at the start or end of records, the central line might move itself, rather than being centred and the spectrograms moving.  Note that playback volume does not affect the colormap of the spectrograms.

To browse another recording, users may return from the SPECTROGRAM VIEW to the MAP VIEW by clicking the sidebar’s Return to Recorder selection button located directly under the miniature map.  Users may also open another browser or browser-tab to start an independent instance of OPUS, allowing side by side comparisons of different recorders.

Entries in the Recorder Metadata tab should be self-explicatory, by and large.  OPUS offers its (level 3+) products, i.e. the spectrogram plots and the compressed audio data under the CC-BY 4.0 license.  Whenever using any of the content provided by OPUS, please attribute to AWI stating “CC-BY 4.0 Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research 2023.”  In the future, OPUS will provide links to the original (level 1+, that is, calibrated and quality controlled) audio data via their respective DOI.  This process (requesting a DOI after submission of appropriate data) will be at the data provider’s discretion.

Logging and exchanging events of interest

Communication with colleagues on interesting observations in the audio stream is facilitated through the Event Management tab, which is located at the bottom of both the MAP VIEW as well as the SPECTROGRAM VIEW.  We first focus on the latter in this section.

A right-click to the time of interest in any spectrogram moves the corresponding Mouse Position into the Last Event Position buffer.  By clicking Add Event you may move it to the event list (centered table of the Event Management tab) and annotate it with a predefined Event Tag, like “sperm whale” from a drop-down list and a Comment, like “very loud” in the adjacent free text field.  You may discard events from the event list by clicking Remove Event.   

Users may sort the event list alphabetically or in time according to each column by clicking into the column headings.  A second click toggles the sorting direction.

Please note that events in the event list are stored only temporary, that is, as long as your browser keeps the OPUS session open.  Event lists become permanent when saved to disk by clicking the Export List button.  The location of the saved event file is determined by the browsers download setting, e.g. in your computers download folder.  Successive saves are stored independently with increasing numerals at the end of the file name.  Event lists may be loaded, e.g., during a later session by clicking to Import List, in either the Spectrogram or Map views.  To exchange information on events with colleagues, either share the event list file with them or copy the html at the top (yet this method is of lesser accuracy with regard to time.)

The following file provides a suite of starter sounds, i.e. selected sounds from the polar oceans, as a starting point for exploring the world’s underwater soundscapes:
Starter sounds
After downloading this list to your computer, you can upload it to OPUS by clicking on the “Import List” button on either the MAP or the SPECTROGRAM VIEW.

Accessing data

The product download tab can be expanded by clicking on the arrow to its right. In the tab appearing, users have the option to download either one or several of the current (as determined by marker position) spectrograms and the associated audio file by selecting the desired OPUS products for download. After clicking the download button, a .zip file containing the selected OPUS products will be downloaded to the location determined by the browsers download setting, e.g. in your computers download folder.

Contact information

Please feel free to contact us anytime at opus-info@awi.de for feedback on the OPUS portal or in case you have any questions.


Appendix: List of predefined signal tags

This is the list of predefined signal tags that users may want to use to categorize/assign events in the Event List.  Use the Comments field to define other terms. 



=== BIOPHONIC (probably) ===


                unassigned (probably baleen whale)

                blue whale

                unassigned (probably toothed whale)

                bowhead whale

                unassigned (probably fish)

                fin whale

                unassigned (probably biophonic)

                humpback whale


                minke whale

                air guns

                sei whale



                electronic noise

                beluga whale

                ship noise


                mooring noise



                pilot whale

                unassigned (probably man made)

                sperm whale


                white-beaked dolphin


=== SEALS ===

                earth quake

                bearded seal

                iceberg collision

                crabeater seal

                ice melting

                harp seal


                leopard seal


                ringed seal

                sea ice motion

                Ross seal



                unassigned (probably geophonic)

                Weddell seal




…idea and conceptual design

Olaf Boebel

...software development

Michael Flau

...software development

Andy Traumüller

…data processing and quality control

Karolin Thomisch

…data and metadata management

Stephanie Spiesecke

…MareHUB/DAM integration

Robin Heß

…functional testing

Linnea Pankoke


Development of OPUS was and is currently funded through PAKT-funds granted by the Bundesministerium für Bildung und Forschung (BMBF) and the Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V. We thank Antje Boetius for applying to and winning this essential financial support as well as Stephan Frickenhaus and Frank Oliver Glöckner for implementing the MARE-HUB projects into which OPUS is embedded. Angela Schaefer and Roland Koppe are recognized of their relentless efforts in managing these projects. Conception of its necessity and many ideas for OPUS implementation evolved out discussions within the International Quiet Ocean Experiment (IQOE). Particular support was given by Ed Urban of IQOE. Discussions within the MANTA team, a concurring and independent software development aimed at creating standardized acoustic metrics triggered many useful discussions on calibration and data management issues.


... ... ...

Legal Information

Legal Notice

for this website in compliance with §5 TMG (German Tele-Media Act)

Helmholtz-Zentrum für Polar- und Meeresforschung
Am Handelshafen 12
27570 Bremerhaven

Legal form: Das Alfred-Wegener-Institut ist eine Stiftung des öffentlichen Rechts.
Representatives: Prof. Dr. Antje Boetius (Direktorin), Dr. Karsten Wurr (Verwaltungsdirektor)
VAT-ID: DE114707273

Phone: +49 471 4831-0
+49 471 4831-1149

Privacy Policy & Terms of Use

By using the OPUS platform you consent to our privacy policy and terms of use.

Liability for Content

We make every effort to keep the information on our website current, but accept no liability whatsoever for the content provided. Pursuant to §7 par. 1 of TMG (German Tele-Media Act), the law limits our responsibility as a service provider to our own content on these Web pages. According to §§8 to 10 of TMG, we are not obligated to monitor third party information provided or stored on our website. However, we shall promptly remove any content upon becoming aware that it violates the law. Our liability in such an instance shall commence at the time we become aware of the respective violation.

Liability for Links

Our site contains links to third-party websites. We have no influence whatsoever on the information on these websites and accept no guaranty for its correctness. The content of such third-party sites is the responsibility of the respective owners and or providers. At the time third-party websites were linked to ours, we found NO GROUNDS WHATSOEVER of any likely contravention of the law. We shall promptly delete a link upon becoming aware that it violates the law.

Platform Design and Implementation

Design: Ocean Acoustics Group, AWI;; AWI's computing centre

Hosted by

Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI)

Supported by

Federal Ministry of Education and Research (BMBF)

International Quiet Ocean Experiment (IQOE)

Making Ambient Noise Trends Accessible (MANTA)

Privacy Policy

Use of personal data

Use of the OPUS portal is possible without any indication of the user´s personal data.

However, if a user seeks to get in contact with the OPUS team, e.g. with specific questions regarding the data or to have their data included in OPUS, they may do so by email to opus-info@awi.de. In doing so, users are implicitly consenting to the standard privacy policy of the email systems used. If in repose to such requests the processing of personal data is necessary and there is no statutory basis for such processing, we generally obtain consent from the data subject.


OPUS only uses necessary functional cookies.

Collection of general data and information

The website of OPUS collects a series of general data and information when a data subject or automated system calls up the website. This general data and information are stored in the server log files. Collected may be (1) the browser types and versions used, (2) the operating system used by the accessing system, (3) the website from which an accessing system reaches our website (so-called referrers), (4) the sub-websites, (5) the date and time of access to the Internet site, (6) an Internet protocol address (IP address), (7) the Internet service provider of the accessing system, and (8) any other similar data and information that may be used in the event of attacks on our information technology systems.

When using these general data and information, OPUS does not draw any conclusions about the user. Rather, this information is needed to (1) deliver the content of our website correctly, (2) optimize the content of our website as well as its advertisement, (3) ensure the long-term viability of our information technology systems and website technology, and (4) provide law enforcement authorities with the information necessary for criminal prosecution in case of a cyber-attack. Therefore, OPUS might analyse anonymously collected data and information statistically, with the aim of increasing the data protection and data security of our institution.

Sign Up / Registration on our website

Access to the OPUS viewer (Version 1.0) via opus.aq is password protected, but requires no registration or sign-up.

Contact possibility via the website

The OPUS.aq viewer displays information that enables a direct communication with the OPUS team and data providers by e-mail.

Scientific data submission via the website

Data cannot be submitted via the website but requires individual arrangements between data providers ad OPUS.Please send requests to OPUS via opus-info@awi.de

Rights of the user

Right of confirmation

Each user shall have the right granted by the European legislator to obtain from the controller the confirmation as to whether or not personal data concerning him or her are being processed. If a user wishes to avail himself of this right of confirmation, he or she may, at any time, contact our Data Protection Officer (datenschutz@awi.de) or another employee of the controller.

Existence of automated decision-making

As a responsible institution, we do not use automatic decision-making or profiling.

Terms and Conditions

Please also visit our legal notice and terms of use establishing the use, disclaimers, and limitations of liability governing the use of our website.

Contacting Us

If there are any questions regarding this privacy policy you may contact us at opus-info@awi.de .

Changes to our Privacy Policy

If we decide to change our privacy policy, we will post those changes on this page. This policy was last modified on 2021-09-10.

This Privacy Policy was adapted from the PANGAEA privacy policy (https://www.pangaea.de/about/privacypolicy.php).The PANGAEA Privacy Policy has been generated by the Privacy Policy Generator of the External Data Protection Officer from DGD Deutsche Gesellschaft für Datenschutz GmbH, which has been developed in cooperation with Media Law Lawyers from WBS-LAW. It was adapted afterwards for use by this website.

Terms of Use

Thank you for your interest in our website and services. Please read these Terms of Use carefully because they are a binding agreement between You and OPUS's hosting institutions.

1. Preliminary statement

The Open Portal to Underwater Soundscapes (OPUS) seeks to serve FAIR (findable, accessible, interoperable and reusable) principles for globally collected passive acoustic underwater sound recordings (i.e. passive acoustic monitoring, PAM, data).In Version 1.0, functionality is by and large restricted to findable.OPUS.aq is a browser based web service with an underlying database (holding metadata) and data collection of PAM recordings and visualizations.

OPUS is being developed under the auspices of the IQOE (International Quiet Ocean Experiment) and the Helmholtz MareHUB and InfInf initiatives, in an effort to allow a broad range of stakeholders (the public, artists, journalists, fellow scientists, regulatory agencies, consulting companies and the marine industry) to learn about and access this data for their respective needs.Hence we seek to develop a robust and scalable solution that allows presentation and access to globally distributed data sets.

The OPUS platform comprises three elements:

         The OPUS.aq viewer, a Internet browser based web service which facilitates browsing, viewing and listening to PAM recordings via their spectrographic visualizations.

         The OPUS metadata base, holding the metadata to each recording, linking the GUI to the data collections.

         The OPUS data collections: Audio and image files containing the recorded sound and their spectrographic representations.

Information on PAM recordings featured by the OPUS.aq viewer are presented in form of a map displaying the location of recordings subject to user selectable temporal and spatial limits.Basic information on a pointed-to recorder is displayed during the mouse's hover-over while in MAP view.

PAM data of a selected recorder (by clicking) is presented in the SPECTROGRAM view in form of a stack of temporally nested spectrograms (annual, monthly, daily, hourly, 10-min and 2-min), allowing the user to select any point in time (data permitting) by clicking into any of the spectrograms.

Users may listen to the corresponding sound files by clicking the PLAY button in the sidebars playback panel.

Users may tag events by right-click and save the corresponding information in OpusLog.txt (or similar) files on their local computer (by default in the 'Download' directory) for later use or exchange with other users.

2. Scope of application

These terms of use governs the provisions of the services and the use of these services offered through the OPUS.aq viewer to their users. The use of the services on the platform is governed exclusively by these terms of use, unless OPUS expressly draws the attention of the user to any supplemental terms.

The user can view and print out the currently valid terms of use via respective links on OPUS.aq website.

3. Subject Matter of the Agreement

OPUS provides the opus.aq viewer for institutions or individual scientists seeking to explore the availability of PAM data throughout the global ocean. The system is operated in the sense of the Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities, which is a follow up to the Budapest Open Access Initiative. The services will be delivered as follows:

3.1 Data submission:

The OPUS.aq viewer (Version 1.0) does currently not support data submission. Third parties interested in having their data featured on OPUS.aq are kindly requested to contact OPUS via opus-info@awi.de.

3.2 Data Discovery:

OPUS.aq provides an open access portal to acoustic and visual representations of passive acoustic data:

Information on PAM recordings accessible through OPUS are presented in form of a map displaying the location of recordings in accord with user selectable temporal and spatial limits.Basic information on a pointed-to recorder is displayed during the mouse's hover-over, while details are revealed in the sidebars METADATA panel after its selection (i.e. clicking to)..

PAM data of the selected recorder is presented in the SPECTROGRAM view in form of a stack of temporally nested spectrograms (annual, monthly, daily, hourly, 10-min and 2-min), allowing the user to select any point in time (data permitting) by clicking into any of the spectrograms. OPUS responds by centring the stack of spectrograms around the selected time. The stack of nested spectrograms thereby serves to identify acoustic events and to explore their temporal features (like seasonal or dial cycles) up to the point of signal recognition (e.g. call identification) by reviewing its spectral characteristics at the highest resolution level.

Users may listen to the corresponding sound files by clicking the PLAY button in the sidebars playback panel. This features two volume controls (volume and boost), allowing listening to hear even rather quiet recordings (though use of headphones or external speaker system is highly recommended to hear < 100Hz sounds).Playback progress is matched by spectrograms being moved to the left, such that the currently playback time is indicated by the white central line in the spectrograms.(Note: Depending on timing, the central line might advance to the right rather than the spectrogram advance left underneath it.)

To browse another recording, users may return from the SPECTROGRAM view to the MAP view by clicking the sidebars Goto Map button.

3.3 Data Publication:

OPUS does not publish data, rather it visualizes published data.Data submitted to the OPUS platform shall be archived at and a DOI be minted by a competent service (such as PANGAEA). The DOI and an email point of contact shall be is included with the recordings metadata, such that the dataset can be referenced and the data provider be contacted.

3.4 Data Retrieval:

OPUS.aq (Version 1.0) does currently not support data retrieval.Third parties interested in accessing data displayed in OPUS.aq are kindly requested to contact the data provider (see respective email in meta data panel) or opus-info@awi.de.

3.5 Contract language is exclusively English.

4. Login to OPUS website

The user is obliged to handle the login-data with care. In particular, the user is prohibited from disclosing the login data to third parties and/or allowing third parties to access the services via the OPUS platform by bypassing the login data. OPUS may change the login data at any should it become aware of any misuse.

5. Conditions of use

5.1 The offered service of data browsing via the OPUS.aq viewer includes the fair use of the access to the open access data platform. OPUS.aq is entitled at its own discretion to technically limit the browsing of research contents through those interfaces of the OPUS platform, which means in particular:

         Requests significantly beyond the average number of access attempts per time unit by other users of the OPUS webservice or

         the use of automated systems to access data via OPUS.aq web pages for commercial purposes except for keeping web search indexes up to date.

         Such exceeding inquiries will automatically lead to error messages and/or a forced disconnection from the service.

5.2 OPUS does not assume any responsibility for the research contents and metadata (contents) - no matter what kind. This responsibility rests solely with the data provider as identified in the corresponding metadata.

5.3 The user must refrain from any activity that could impair the operation of the OPUS platform or the technical infrastructure behind it. These included in particular:

         the use of software, scripts or databases in connection with the use of the OPUS platform;

         the automatic reading, blocking, overwriting, modifying, copying of data and/or other content, unless this is necessary for the proper use of the platform.

5.4 Should there be any disruptions in the use of the platform or its functionalities, the user shall inform OPUS of this disruption immediately. The same applies if the user obtains information about content published by third parties which obviously violates applicable law or the rights of third parties.

5.5 OPUS can temporarily or permanently block or delete the access to the services at the OPUS platform, if there is concrete evidence that a user is violating these terms of use or the applicable law or if OPUS has any other justified interest in blocking.

6. Rights of use

6.1 The OPUS platform provides its content under the Creative Commons license CC0 for metadata and CC-BY 4.0 for acoustic and visual representations for data and underlying code.

CC0 allows unrestricted use of the information.

CC-BY 4.0 implies that users are free toshare (copy and redistribute) acoustic and visual representations of featured PAM data in any medium or format, adapt (remix, transform, and build upon) the material for any purpose, even commercially, provided they give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. Additionally, users may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

Appropriate credit is given by providing of the following statement:

CC BY 4.0, Alfred Wegener Institute, DOI:..- if available

7. Protection of content/Responsibility for content

7.1 The contents provided by OPUS may only be used in accordance with these terms of use and the applicable law.

7.2 OPUS does not check the completeness, accuracy and legality of the research contents of the data providers. OPUS therefore assumes no responsibility for the completeness, accuracy, legality and topicality of these research contents. This also applies to the quality of the research contents and their suitability for a specific purposes.

8. Privacy Policy

All information on the processing of personal data can be found in the privacy policy of OPUS.

9. Liability

9.1 Those contents available on the OPUS platform provided by OPUS were created with best care and attention and will be updated on a regular basis. OPUS does not accept liability for the quality, topicality or completeness of the contents provided by OPUS offered on the OPUS platform and their suitability for specific purposes. Liability claims which refer to material and/or non-material damage, which are caused by the use or disuse of the offered contents provided by OPUS on the OPUS platform respectively the use of inaccurate and incomplete contents are excluded, insofar as there is no evidence of wilful or gross negligence on the part of OPUS. All offers are non-binding and without obligation. For damages resulting from slightly negligent violations of essential contractual obligations, the liability is limited to typical or foreseeable damages. The above limitations of liability also apply in the event of breaches of duty by the legal representatives, senior employees, or vicarious agents of OPUS. OPUS is liable for damages resulting from injury to life, body or health, which are based on a wilful and negligent breach of duty, as well as for damages according to the Product Liability Act without limitations.

9.2 OPUS is not liable for damages whose causes are beyond its control, in particular not for damages due to force majeure or for damages caused by users or third parties in violation of these terms of use.

9.3 OPUS expressly reserves the right to edit, expand or delete sections of pages, or the entire publication, or to suspend publication temporarily or permanently, without separate announcement.

9.4 OPUS does not guarantee that the OPUS platform is compatible with the hardware and software of the devices of the user. In addition, OPUS does not guarantee that this content is available at any time or at certain times without restriction or that it meets certain performance or functional requirements.

10. Termination of use

10.1 OPUS and the user may terminate the user relationship at any time, without the need for a reason. The user may terminate the user relationship by discontinuing the use of the services via the OPUS platform.

11. Amendment of the terms of use

11.1 OPUS is entitled to amend or supplement the provision of these terms of use at any time with effect for the future, if this is required due to legal or functional adaptations of the OPUS platform, for example in the case of technical changes.

11.2 Any amendments or supplements will be published via the OPUS website.

12. Final provisions

12.1 Should any provision of these terms of use be or become ineffective, this shall not affect the validity of the remaining provisions.

12.2 These terms of use are subject to German law. The place of jurisdiction for all disputes arising from these terms of use is, as far as legally permissible, Bremen.

These Terms of Use were last updated on 2021-09-10 (version 1.0).


Copyright of website elements

This website (code and all graphic elements other than representations of scientific data) are


Copyright of image and audio products

All material provided through this website, particularly spectrographic images and audio data is copyrighted under CC-BY 4.0.This implies that products and derivatives thereof may be copied, modified and redistributed in commercial and non-commercial contexts as long as the source is properly attributed.Proper attributions includes naming of the following reference:

CC-BY 4.0 AWI Bremerhaven, [year of download] and, if available the DOI of the respective recording/recordings