GCRI · Oceans and Coasts
Marine ecosystems
Coral reefs, mangroves, seagrass meadows, kelp forests and open-ocean ecosystems support fisheries, protect coasts and store carbon. They are under pressure from warming, marine heatwaves, acidification, loss of oxygen, pollution and overfishing. This page sets out how these pressures act and combine, how ecosystem condition is observed, and what evidence serves the agencies and communities that protect and restore them.
Marine ecosystems on the record.
Marine ecosystems: how the risk develops.
Habitats, trophic systems and ecosystem condition. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Marine heatwaves bleach and kill
Prolonged high sea temperatures cause coral bleaching, kelp loss and mass mortality of other species. Heatwaves are becoming more frequent and intense.
Acidification changes chemistry
The ocean absorbs carbon dioxide, lowering pH and the carbonate available to corals, shellfish and plankton to build shells and skeletons.
Oxygen is declining
Warmer water holds less oxygen and nutrient runoff fuels algal blooms that consume it. Low-oxygen zones expand and drive species away or kill them.
Pressures combine
Reefs stressed by pollution and overfishing recover more slowly from bleaching. Loss of habitat-forming species cascades through the food web and the services ecosystems provide.
Ocean state in Pacific Island states.
Marine heat, sea temperature and chlorophyll over Pacific Island states, from NASA GIBS. Each layer carries its own date.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 3
Ocean state, for this page
About this layer
- Evidence
- Observed
- Source
- GHRSST MUR25 (NASA JPL PO.DAAC)
- Provider
- NASA JPL PO.DAAC
- Licence
- NASA open data
- Vintage
- daily; Satellite analysis
- Newest at build
- 2026-10-12
- Resolution
- about 2 km grid
- Uncertainty
- Satellite analysis of how far sea temperature departs from its usual value for the date shown; a marine heat indicator, not a coral bleaching alert.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed
- Source
- GHRSST MUR (NASA JPL PO.DAAC)
- Provider
- NASA JPL PO.DAAC
- Licence
- NASA open data
- Vintage
- daily; Satellite analysis
- Newest at build
- 2026-10-12
- Resolution
- about 1 km grid
- Uncertainty
- Gap-filled satellite analysis of sea surface temperature for the date shown; not a reef or species condition report.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds and sun glint leave gaps)
- Source
- MODIS Aqua ocean colour (NASA OB.DAAC)
- Provider
- NASA OB.DAAC
- Licence
- NASA open data
- Vintage
- daily; Satellite retrieval; clouds and sun glint leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 1 km grid
- Uncertainty
- Satellite estimate of chlorophyll-a near the sea surface on the day shown, an indicator of plankton and ocean productivity; not a measure of fish stocks or harmful blooms.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Modelled (latest year GIBS publishes)
- Source
- MODIS Terra and Aqua land cover (MCD12Q1) (NASA LP DAAC)
- Provider
- NASA LP DAAC
- Licence
- NASA open data
- Vintage
- yearly; Satellite classification; latest year GIBS publishes
- Newest at build
- 2024-01-01
- Resolution
- about 500 m grid
- Uncertainty
- Satellite land cover classes for the year shown, including croplands; a classification with known errors, not a farm register.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed
- Source
- VIIRS NOAA-20 corrected reflectance (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite image
- Newest at build
- 2026-10-14
- Resolution
- about 250 m grid
- Uncertainty
- Satellite image. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds leave gaps)
- Source
- MODIS Terra EVI (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite index; clouds leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 250 m grid
- Uncertainty
- Satellite vegetation index for the 8 days to the date shown, a habitat condition indicator; not a measure of species or biodiversity.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
Keyboard, with the map focused
Hold Ctrl or ⌘ and scroll to zoom
Latest available
NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
Loading the latest NASA imagery.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
Ocean state, framed on Pacific Island states.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.
Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · NASA JPL OPERA DIST-ALERTSources and licences
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- GHRSST Level 4 MUR analyses, NASA Jet Propulsion Laboratory; distributed by the NASA Physical Oceanography DAAC (PO.DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- MODIS Aqua ocean colour, NASA Ocean Biology Processing Group; distributed by the NASA Ocean Biology DAAC (OB.DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
- Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
- © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
- Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
- Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
- Live: NASA EONET Events are indicative, not authority warnings.
- Observed (EO): NASA JPL OPERA DIST-ALERT (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- NASA GIBS: We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- Weather data by Open-Meteo.com (https://open-meteo.com/), licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
- Optional layers (10 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
- Sea surface temperature anomaly: GHRSST MUR25, NASA JPL PO.DAAC · 12 Oct 2026
- Sea surface temperature: GHRSST MUR, NASA JPL PO.DAAC · 12 Oct 2026
- Ocean chlorophyll-a concentration: MODIS Aqua ocean colour, NASA OB.DAAC · 12 Oct 2026
- Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
- True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
- Enhanced vegetation index, rolling 8 days: MODIS Terra EVI, NASA LANCE · 13 Oct 2026
Marine ecosystems feed people and protect coasts.
- BiodiversityCouplingReefs, mangroves and seagrass hold much coastal biodiversity.What to watchHabitat extent and condition
- FoodCouplingReef fisheries are a protein source for coastal communities.What to watchReef fish catch
- HealthCouplingHealthy reefs and mangroves buffer storm impacts on people.What to watchWave attenuation
Ecosystem analyses are designed for the Global Systems Risk and Resilience series. The GCRMN status report (2021) documents reef change; marine heatwaves caused the fourth global bleaching event confirmed in 2024.
- Reef and mangrove survey data.
- Local ecological knowledge shared with consent.
Fisheries and marine watch.
The screen a team would use to follow this subject: its measures, states and decisions. Names are examples and values are illustrative.
Fisheries and marine watch
Marine ecosystems · Fishing grounds 3 · Season 1
- Biomass vs reference point0.8ratioWatch
- Marine heatwave days50this yearAlert
- Fleet effort111index
Sea surface temperature anomaly
Stock status
| Small pelagic | 0.9 | 1.0 | Overfishing |
| Reef fish | 0.7 | 1.6 | Overfished |
| Tuna-like | 1.2 | 0.8 | Sustainable |
What is measured, and how well.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Degree heating weeks | degree Celsius weeks | daily | Satellite sea surface temperature products | OBSERVED |
| Live hard coral cover | percent of reef area | per survey | Reef monitoring surveys | OBSERVED |
| Mangrove extent | square kilometres | annual | Satellite mapping | OBSERVED |
| Surface ocean pH | pH units | per cruise or mooring | Ocean carbon observations | OBSERVED |
| Dissolved oxygen | micromoles per kilogram | per profile | Floats and ship observations | OBSERVED |
| Marine protected area coverage | percent of national waters | annual | World Database on Protected Areas | Published statistics |
| Species occurrence records | count by taxon and area | continuous | Biodiversity databases | REPORTED |
Model marine ecosystems as a system. Run the cascade.
Assembled from the Nexus Standards area profile Oceans and coasts risk standards: the hazards it names, the systems and sectors that carry the loss, the controls that dampen it and the data that observe it. Choose the components, pick an initiating hazard and step through the cascade. The Map view places the run on an example geography with open data. Every coupling weight is a stated assumption you can change. A teaching model, not a forecast, an assessment or a certification. To model a place of your own choosing, open the full System Builder.
Hazards
- Sea-level rise
- Storm surge
- Coastal erosion
- Heatwave
- Ocean acidification
- Harmful algal bloom
- Extreme fire weather (set off downstream)
- Wildfire (set off downstream)
- Heat-driven grid stress (set off downstream)
- Agricultural drought (set off downstream)
- Flash drought (set off downstream)
- Snow drought (set off downstream)
- Ground-level ozone episode (set off downstream)
- Meteorological drought (set off downstream)
- River flood (set off downstream)
- Coastal flood (set off downstream)
- Estuary flood (set off downstream)
- Mass displacement (set off downstream)
Systems and couplings
- Oceans and coasts risk standards
- Supply chain and trade risk Cascade
- Food and agriculture risk standards Cascade
- Climate risk standards Common driver and feedback
- Cities and urban systems risk standards Exposure
Controls
NS-0Constitution and principlesNS-1The UNI and the artefact catalogue (grammar v0.2: domain, sector, region and environment segments)NS-3Risk record UNIs (grammar, legacy crosswalk, allocation authority)NS-3bDataset and product metadata profile (STAC, DCAT, PROV-O)NS-5Figure, map and visualisation standard (with the UI/UX kit)NS-9Contextual UNIs (deployments, instances, programme instances)NS-11Verification and monitoring (evidence, attestations, zero-trust conformance observation)NRS-X3Oceans and coasts riskNRS-H11Hazard family: Coastal and sea-level hazards (NHS-1 water.coastal)NRS-H79Hazard family: Mental health crises (NHS-1 health.mental)NRS-H12Hazard family: Ocean-state extremes (NHS-1 water.ocean-state)NRS-H67Hazard family: Ocean circulation and marine tipping (NHS-1 planet.ocean-tipping)NRS-K18Domain pack profile: Oceans coastal (DOMAIN-018)
Observation
- Copernicus Marine Service ocean products (listed for reference)
- Coral Reef Watch daily 5 km heat stress products (listed for reference)
- PSMSL tide gauge mean sea level records (listed for reference)
- GEBCO global bathymetric grid (listed for reference)
- Argo float profiles (listed for reference)
- Average marine acidity (pH) measured at agreed suite of representative sampling stations
- Index of coastal eutrophication and floating plastic debris density
- Direct economic loss attributed to disasters in relation to GDP, including damage to critical infrastructure
Example geography
- Pacific Island states: 150 hexagonal cells
- Night lights tonight, outages (VIIRS Day/Night Band), NASA GIBS
- Surface water through cloud, 30 m (OPERA DSWx-S1 radar), NASA GIBS
- Rain rate, last half hour (IMERG), NASA GIBS
- Surface air temperature, daytime (AIRS), NASA GIBS
Where the evidence comes from.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| NOAA Coral Reef Watch | Satellite sea surface temperature and bleaching heat stress products | Public domain, US government data |
| Allen Coral Atlas | Maps of shallow coral reef habitats and bleaching monitoring | Open, CC BY 4.0 |
| Global Mangrove Watch | Mangrove extent and change | Open, CC BY 4.0 |
| Ocean Biodiversity Information System (OBIS) | Marine species occurrence records | Open, CC0, CC BY or CC BY-NC per dataset |
| Protected Planet (World Database on Protected Areas) | Marine protected areas and OECMs | Free for non-commercial use, terms to check |
| Global Ocean Acidification Observing Network data | Ocean carbonate chemistry observations | Open, terms per data provider (to check) |
The sector signature of marine ecosystems.
The sectors marine ecosystems touches and how strongly they depend on each other: what a study has to observe and model together.
Signature
Biodiversity and its partners
Biodiversity gives pollination and soils to food (0.6), watershed regulation to water (0.5) and zoonotic spillover and medicines to health (0.4).
W · E · I · F · H · B
- Sectors
- 4 of 6
- Relations
- 6 of 15
- Coupling
- 0.46 share of total
Strongest relations in play
- Food → Biodiversity · land conversion0.6
- Water → Food · irrigation0.8
- Water → Biodiversity · environmental flows0.6
- Food → Health · nutrition0.7
Who decides, and what the evidence serves.
Oceans and Coasts prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Marine park and environment agencies | Where to protect, restore or reduce local pressures | Habitat maps; pressure overlays; heat stress |
| Fisheries authorities | Whether to adjust fishing in degraded habitats | Habitat condition and species evidence |
| National biodiversity planners | How to meet marine protection and restoration targets | Protected area coverage; habitat change |
Outputs this topic produces
- Heat stress and bleaching evidence summaries for reef managers
- Habitat extent and change maps for mangroves, seagrass and reefs
- Pressure overlays combining warming, pollution and fishing
- Restoration evidence notes
How marine ecosystems is modelled, measured and tested.
The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.
Earth observation chain
How a satellite or sensor record becomes evidence on marine ecosystems, and where each step adds uncertainty.
- 01 · Acquireorbit, sensor and revisitUncertainty: gaps from cloud and orbit
- 02 · Calibrateradiometric and geometricUncertainty: sensor drift
- 03 · Correctatmosphere and terrainUncertainty: aerosol and slope assumptions
- 04 · Retrieve or classifythe variable or the classUncertainty: model and training error
- 05 · Validateagainst ground truthUncertainty: sample design and size
- 06 · Publishwith error bars and lineageUncertainty: stated, never hidden
The questions experts ask.
- What is the current condition of a habitat, and how does it compare to a baseline?
- Which pressures drive change here, and how do they interact?
- Are thresholds or tipping points near, beyond which recovery becomes unlikely?
- How do changes at one level of the food web propagate to others?
- Which protection or restoration measures are effective, and over what time?
Pressures and responses.
Marine heatwaves cause coral bleaching, kelp loss and mass mortality of invertebrates; as they become more frequent, the time for recovery between events shortens. Ocean acidification, the fall in pH as seawater absorbs carbon dioxide, makes it harder for corals, shellfish and some plankton to build carbonate structures. Deoxygenation, from warming and from nutrient run-off, expands low-oxygen zones that exclude many species. Species ranges shift towards the poles and to deeper water, reorganising communities.
These climate pressures act alongside overfishing, habitat destruction from trawling and coastal development, pollution and invasive species. Interactions are often non-additive: a reef weakened by pollution recovers more slowly from bleaching, and the loss of grazing fish can let algae overgrow corals. Food webs transmit change, through trophic cascades in which the removal of a predator or the collapse of a prey species reshapes the whole system.
Restoration science is advancing, with active coral gardening, mangrove replanting and seagrass recovery, but success depends on addressing the pressures that caused the loss and on choosing sites where conditions will remain suitable.
Survey, sensing and modelling.
Transects and monitoring
Diver and video surveys, eDNA and long-term monitoring sites give direct evidence but cover small areas.
Habitat mapping
Satellite and aerial imagery map shallow habitats and sea-surface temperature; depth and turbidity limit what can be seen.
Ecosystem models
Food-web and species-distribution models explore scenarios; they depend on assumptions about behaviour and adaptation.
Limits: baselines are often missing or already degraded, so condition is measured against a shifted reference. Deep-sea and open-ocean ecosystems remain sparsely observed.
How it is studied, and what the methods cannot say.
- 01Ecology and biodiversity scienceReef condition monitoring · Stock assessment inputs · Restoration monitoringApplied here
- 02Ocean and coastal scienceRegional sea-level budgets · Marine heatwave analysis · Wave climate assessmentApplied here
- 03Earth observation and remote sensingOcean colour and blooms · Shoreline change mapping · Coastal habitat mappingApplied here
- 04Geospatial information systemsCoastal exposure mapping · Marine spatial planning layers · Fishing effort mappingApplied here
Where this page’s references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
Questions and answers.
What causes coral bleaching?
What is ocean acidification?
What are blue carbon ecosystems?
Can damaged reefs recover?
Does the platform rate ecosystem health?
How does this relate to Biodiversity Nexus?
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