--- title: "Underwater noise monitoring | Nexus Observatory" description: "Shipping, piling and seismic surveys fill the sea with sound that whales, dolphins and fish depend on hearing through. Hydrophone moorings measure that sound…" url: https://observatory.global/industries/oceans/underwater-noise/ publisher: Nexus Observatory Inc. updated: 2026-11-02 --- [Nexus Observatory](https://observatory.global/) / [Oceans](https://observatory.global/industries/oceans/) / [Specialized fields](https://observatory.global/industries/oceans/fields/) / **Underwater noise** # The sea's soundscape, measured. Shipping, piling and seismic surveys fill the sea with sound that whales, dolphins and fish depend on hearing through. Hydrophone moorings measure that sound to agreed metrics, so regulators track the trend, builders show they kept piling within limits and marine life is protected. [Plan a deployment](https://observatory.global/contact/deployment/) How it works [Station Builder](https://observatory.global/studio/builder/) **Industry**: Oceans **Measurements**: 4 **Sources cited**: 3 1. Oceans · Underwater noise A sea full of sound Shipping, piling and seismic surveys fill the sea with sound. Whales, dolphins and fish depend on hearing to feed, navigate and find each other, and noise masks it. Underwater noise is now a measure of good environmental status, and offshore construction must keep piling within limits. 2. What is measured Calibrated hydrophones Calibrated hydrophones on moorings record the sea's sound continuously, from ship noise in low frequency bands to the impulses of piling and the calls of marine mammals. Each hydrophone is calibrated before deployment and again on recovery, so levels are comparable across sites. InstrumentsCalibrated hydrophones · Recorders · Surface buoys 3. The base node Levels and detections at sea The node computes band levels and sound exposure to the agreed metrics, detects marine mammal calls and piling strikes, and sends compact summaries. The recorder keeps the full audio for recovery, so every summary can be checked against what was heard. 4. Radio and links Summaries to shore Moorings near shore send band levels and detections over cellular; offshore moorings send them through a satellite terminal. Summaries reach regulators' regional systems and construction control rooms, while full recordings come home on recovery. When one path fails, the other carries the data. LinksPublic cellular · Satellite 5. How it works From a whale call to a piling pause During offshore piling, a mooring detects porpoise clicks close to the site. The node alerts the control room with the detection and the current sound exposure. Piling pauses under the permit's conditions until the animals move away, and the record shows every decision. 6. From order to operation · Order Scope the duty The scope reads the regulator's monitoring duties or the construction permit's noise conditions, shipping and species, and existing moorings. Nexus Observatory Inc. returns the mooring plan, metrics, detection models and a price per mooring and per year. The scope is agreed before any site work begins. [Plan a deployment](https://observatory.global/contact/deployment/) 7. From order to operation · Survey Survey positions Crews survey positions for depth, seabed, distance from shipping lanes and construction, trawling activity and coverage for reports. Positions follow the monitoring guidance so results compare across the region. Findings shape the kit for each site before anything is built. 8. From order to operation · Permits Maritime consent Moorings are approved by the maritime authority, marked to the rules for their area and published in notices to mariners. Fishing communities are told of positions to avoid trawl losses. Every approval is kept with the mooring record. No crew goes to site before its approvals are in place. 9. From order to operation · Build Calibrate hydrophones Hydrophones and recorders are calibrated across the frequency bands, nodes configured with the metrics and detection models and enrolled with their identities, and the system is tested end to end before shipping. Nothing ships until the whole kit has passed its tests together. [Open the Station Builder](https://observatory.global/studio/builder/) 10. From order to operation · Install Deploy moorings Crews deploy each mooring from a vessel, with the hydrophone at its design depth and the surface buoy above, record positions and depths, and watch the first reports arrive before leaving. Crews follow the site safety plan throughout the work. 11. From order to operation · Commission Commission the levels Each node proves its identity. Band levels are checked against a reference hydrophone or known sources, detections against expert review, and reports against the recorder's full audio. The mooring enters service when checks pass. Acceptance is recorded with the owner before handover. 12. From order to operation · Operate Track the soundscape Regulators see band levels and their trend; construction teams see sound exposure during piling and stop when limits or marine mammals require; researchers receive detections and recordings. Every alert and action is kept on the record. Reports for owners and funders come from the same record. 13. From order to operation · Maintain Recover, recalibrate, redeploy Moorings are recovered on schedule, recordings retrieved, hydrophones recalibrated and moorings redeployed. Software updates roll out remotely, and every change and calibration is kept with the mooring record. Maintenance history stays with each site for its whole life. Spares and procedures travel with the crews. [Book field services](https://observatory.global/contact/field-service/) 14. Data products For regulators and builders Marine regulators receive noise band levels and trends; offshore construction teams receive piling sound exposure; researchers and observers receive marine mammal detections; scientists receive calibrated recordings, each tied to mooring, depth and time. Every product can be traced back to its readings. [See the data products](https://observatory.global/data-products/) 15. Evidence Agreed metrics, calibrated Monitoring follows the marine strategy directive's noise descriptor and its monitoring guidance, terms follow the international underwater acoustics standard, and hydrophones are calibrated before and after deployment. Every level keeps its calibration and every detection its review. The record is kept for as long as the duty lasts. Drawn againstDirective 2008/56/EC · Monitoring Guidance for Underwater Noise in European Seas · ISO 18405 16. What you get Ocean and coastal observing Moored buoys, profiling floats, tide and wave gauges, coastal radar and AIS reception with quality-controlled feeds. Delivered as managed service and data licence, for ports, coastal agencies, offshore energy, fisheries. Scale: Coastline to basin. Service levels are written as numbers you can measure on your own dashboard. [Talk to sales](https://observatory.global/contact/sales-enquiry/) 17. Next step Plan underwater noise with us Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for underwater noise. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace. [Plan a deployment](https://observatory.global/contact/deployment/) [Open the Station Builder](https://observatory.global/studio/builder/) [Open the Studio](https://observatory.global/studio/) **01** The place and its hazards ## Where it runs, and what can go wrong. Operating contextUnderwater noise is a descriptor of good environmental status in the marine strategy framework directive, with monitoring guidance that sets frequency bands and metrics; underwater acoustic terms are standardised internationally. Offshore construction permits often require noise limits during piling and the presence of marine mammals to be checked. Hazards - Shipping noise masking whale and dolphin calls - Impulsive piling noise during offshore construction - Moorings lost to trawling - Hydrophones fouled or flooded - Huge recordings no one can analyse **02** What must be measured ## What, where, how often, and under which rules. Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below. | Measurement | Where | Cadence | Sources | | --- | --- | --- | --- | | Ambient noise in standard bands | Hydrophones on moorings | Continuous, band levels each minute | 12 | | Impulsive sound exposure | Hydrophones near construction sites | Continuous during piling | 23 | | Marine mammal detections | Hydrophones with detection models | Continuous | 1 | | Hydrophone calibration | Each hydrophone and recorder | Before deployment and on recovery | 32 | **03** The observation stack ## From one base unit to a network. The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol. 1. **01** Base unit A mooring: a calibrated hydrophone and recorder with a surface buoy and node. [Build a station →](https://observatory.global/studio/builder/) 2. **02** Site A site: moorings around a shipping lane, a port or a construction site, reporting to shore. [Plan a site →](https://observatory.global/contact/deployment/) 3. **03** Fleet A regional network run to the agreed bands and metrics. [Managed offers →](https://observatory.global/industries/oceans/solutions/) 4. **04** Network Regulators and researchers share noise levels and detections through regional data systems. [The open protocol →](https://observatory.global/protocol/) - **01** Acoustic sensor - **02** Moored buoy - **03** Micro node (Nano) - **04** 3GPP NTN terminal - **05** Cellular modem/router - **06** Solar array Radio and links ### Public cellular Moorings near shore report band levels and detections over cellular. Radio and links ### Satellite Offshore moorings report through a satellite terminal. Edge computeThe node computes band levels and sound exposure, detects marine mammal calls and piling strikes, and sends compact summaries while the recorder keeps the full audio for recovery. PowerThe surface buoy carries solar panels and batteries; the hydrophone recorder has its own battery for the deployment. **04** How it works ## From the instrument to the product. One observation's path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks. Underwater noise: data path – of 06 01 Instruments Measurement with sensor identity andcalibration 02 Node – Wrap in an observation envelope with timequality– Measure quality and uncertainty, attachquality flags– Buffer locally (store-and-forward when thelink drops) 03 Backhaul Commit with transactional outbox andpublish, delivered at least once 04 Site Consumer inbox deduplicates and applieseach record once into governed data 05 Data store Governed product through API, map orexport, correction-aware 06 Products netCDF-CFMQTTOGC SensorThings API 07 Power and structure Supplies 12 V DC to the field equipment 01 Acoustic sensor SDI-12 · RS-485 · Ethernet 02 Moored buoy RS-485 · SDI-12 03 Micro node (Nano) Ethernet · USB · Analogue I/O ·RS-485 · CAN 04 3GPP NTN terminal Ethernet · USB · RS-232 05 Cellular modem/router Ethernet · USB · RS-232 Site MQTT 5 with Sparkplug B Governed data store Versioned, correction-aware Noise band levels and trends Piling sound exposure Marine mammal detections Calibrated recordings 06 Solar array RS-485 Ethernet · MQTT 5 RS-485 Ethernet Ethernet 3GPP NTN LTE/NR From the instrument to the published product: each band is a tier, each connector names its interface, and the numbers match the bill of materials. Hover or focus a block to trace its path; scroll or step to follow one observation. | Item | Equipment | Data ports | Protocols | Power in | | --- | --- | --- | --- | --- | | 01 | **Acoustic sensor** Sound level meter, acoustic event detector or infrasound array element. | SDI-12RS-485Ethernet | SDI-12, Modbus, MQTT 5, OGC SensorThings API | 12 V DC | | 02 | **Moored buoy** Moored buoy platform carrying met-ocean sensors, with solar power and satellite or cellular telemetry. | RS-485SDI-12 | MQTT 5, OGC SensorThings API | 12 V DC | | 03 | **Micro node (Nano)** Single-board or module-class node for sensor sites, gateways and low-power deployments. | EthernetUSBAnalogue I/ORS-485CAN | MQTT 5, OMA LwM2M, CoAP | PoE, 12 V DC, USB PD | | 04 | **3GPP NTN terminal** Terminal using the 3GPP non-terrestrial network air interface (NR-NTN or IoT-NTN) to reach a satellite access node directly. | EthernetUSBRS-232 | 3GPP NR or IoT NTN, OMA LwM2M, MQTT 5 | 12 V DC, Internal battery | | 05 | **Cellular modem/router** LTE or NR modem or router that uses a public carrier or private network as backhaul. | EthernetUSBRS-232 | 3GPP E-UTRA air interface, 3GPP NR air interface, OMA LwM2M | 12 V DC, PoE | | 06 | **Solar array** PV modules with charge controller sized to the site's load and climate. | RS-485 | Modbus | — | How it scales 01 Instruments Arbitrary qualified sensors and instruments whosemeasurements are ingested with calibration, units,geometry, time, custody and uncertainty. ×n 02 Node The minimum useful deployable unit: server, ruggedappliance, radio node, sensor gateway, satelliteterminal, AI, scientific, vehicle or virtual node. Node Node agent 03 Site The minimum independently operable localgovernance and failure domain: one or more nodesplus local network, identity, policy, evidence,storage, products and operator surfaces. SITE Node Node Node ×n 04 Cluster An optional scale or specialisation domain forscheduling, shared storage, accelerators or datalocality. CLUSTER ×n 05 Fleet Coordinates plans, acknowledgements,convergence evidence, update campaigns andcorrection propagation across nodes and sites. FLEET Fleet controller ×n 06 Federation An exchange of products, capabilities, events orwork across approved, independently administeredtrust domains, using explicit trust, policy,data-locality, version and correction contracts. TRUST DOMAIN TRUST DOMAIN TRUST DOMAIN ×n Verifier Applications Data in the field Telemetry Control Data upstream Control Data upstream Control Exchange Evidence Events Exchange The smallest deployable unit is one node; the same unit is replicated to meet the demand. Nodes form a site, sites may form a cluster, sites and clusters are coordinated as a fleet, and fleets exchange across independently administered trust domains. Each plane is a separate channel with its own open binding. **Data in the field**: MQTT 5 with Sparkplug B; connectors for LoRaWAN, OPC UA and instrument buses. **Telemetry**: OpenTelemetry OTLP. **Control**: TLS 1.3 with mutual authentication; protobuf messages over gRPC or HTTP/2. **Data upstream**: At-least-once publication with repeat-safe keys over the control channel or NATS JetStream; QUIC MAY be used on lossy links. **Evidence**: DSSE-signed in-toto statements; SLSA provenance; SCITT transparency receipts. **Events**: Event envelopes mapped to CloudEvents 1.0; channels described in AsyncAPI 3. **Exchange**: OpenAPI 3.1; the OGC API family; SensorThings; STAC; WIS 2.0. **05** From order to operation ## Every step, from the first call to a running site. The same crew and the same record carry the work from scope to maintenance. 1. 01 Order Scope the duty The scope reads the regulator's monitoring duties or the construction permit's noise conditions, shipping and species, and existing moorings. Nexus Observatory Inc. returns the mooring plan, metrics, detection models and a price per mooring and per year. The scope is agreed before any site work begins. 1 2. 02 Survey Survey positions Crews survey positions for depth, seabed, distance from shipping lanes and construction, trawling activity and coverage for reports. Positions follow the monitoring guidance so results compare across the region. Findings shape the kit for each site before anything is built. 2 3. 03 Permits Maritime consent Moorings are approved by the maritime authority, marked to the rules for their area and published in notices to mariners. Fishing communities are told of positions to avoid trawl losses. Every approval is kept with the mooring record. No crew goes to site before its approvals are in place. 4. 04 Build Calibrate hydrophones Hydrophones and recorders are calibrated across the frequency bands, nodes configured with the metrics and detection models and enrolled with their identities, and the system is tested end to end before shipping. Nothing ships until the whole kit has passed its tests together. 3 5. 05 Install Deploy moorings Crews deploy each mooring from a vessel, with the hydrophone at its design depth and the surface buoy above, record positions and depths, and watch the first reports arrive before leaving. Crews follow the site safety plan throughout the work. 6. 06 Commission Commission the levels Each node proves its identity. Band levels are checked against a reference hydrophone or known sources, detections against expert review, and reports against the recorder's full audio. The mooring enters service when checks pass. Acceptance is recorded with the owner before handover. 2 7. 07 Operate Track the soundscape Regulators see band levels and their trend; construction teams see sound exposure during piling and stop when limits or marine mammals require; researchers receive detections and recordings. Every alert and action is kept on the record. Reports for owners and funders come from the same record. 1 8. 08 Maintain Recover, recalibrate, redeploy Moorings are recovered on schedule, recordings retrieved, hydrophones recalibrated and moorings redeployed. Software updates roll out remotely, and every change and calibration is kept with the mooring record. Maintenance history stays with each site for its whole life. Spares and procedures travel with the crews. 3 **06** Data products and integration ## What it delivers, to whom, and into which systems. Data products - **Noise band levels and trends** Marine regulators - **Piling sound exposure** Offshore construction teams - **Marine mammal detections** Researchers and observers - **Calibrated recordings** Scientists Integration - **Regional data systems** Band levels are submitted in the regional formats. - **Construction control** Exposure and detections reach the piling control room. - **Research** Recordings are shared with researchers. Exchanged through netCDF-CF, MQTT, OGC SensorThings API. **07** Questions buyers ask ## Before you scope it. Which metrics do you report? The bands and metrics set in the monitoring guidance. Can it stop piling? It alerts the control room; the decision is the operator's under its permit. What about trawling? Positions are published and agreed with fishers. Is the audio kept? Yes, on the recorder for recovery. **08** Resources ## The sources behind this page. Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does. 1. **1** [Directive 2008/56/EC establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive)](https://eur-lex.europa.eu/) European Union · 2008 2. **2** [Monitoring Guidance for Underwater Noise in European Seas](https://publications.jrc.ec.europa.eu/) European Commission Joint Research Centre · 2014 3. **3** [ISO 18405: Underwater acoustics, terminology](https://www.iso.org/) International Organization for Standardization · 2017 **09** Related ## Use cases and solutions. [Use case Bioacoustic biodiversity observatoryOpen-hardware acoustic recorders on solar power with low-power radio or satellite uplink, for species baselines.The full use case →](https://observatory.global/use-cases/bioacoustic/) [Solution Ocean and coastal observingMoored buoys, profiling floats, tide and wave gauges, coastal radar and AIS reception with quality-controlled feeds.Solutions for oceans →](https://observatory.global/industries/oceans/solutions/#ocean-coastal) [Solution Environmental and permit monitoringEmissions, water quality, noise and dust monitoring for permit conditions, with traceable calibration and evidence bundles.Solutions for oceans →](https://observatory.global/industries/oceans/solutions/#environmental-compliance) [Solution Biodiversity and habitat monitoringAcoustic sensors, camera traps that exclude people, eDNA sampling logistics and EO habitat change for nature programmes and disclosures.Solutions for oceans →](https://observatory.global/industries/oceans/solutions/#nature-monitoring) **10** Oceans: specialized fields ## Other fields of this industry. [Specialized field Sea level and storm surgeTide gauges with land-motion GNSS and weather at harbours and coasts, giving real-time surge for warnings and long sea-level records tied to the land they stand on.The full field →](https://observatory.global/industries/oceans/sea-level/) [Specialized field Waves and coastal buoysMoored buoys that measure waves, wind and sea temperature off ports and coasts, for safe navigation, coastal design and the warnings that keep people off dangerous seas.The full field →](https://observatory.global/industries/oceans/wave-buoys/) [Specialized field Coastal and bathing water qualitySondes and samplers at beaches, estuaries and aquaculture zones that watch temperature, oxygen, turbidity and algal blooms, so authorities protect bathers and shellfish in time.The full field →](https://observatory.global/industries/oceans/coastal-water-quality/) ### Bring us the site. Plan a deployment, configure a station, model it in the Studio or talk to sales. 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