Ecoregion
Explore the Mariana Trench
Use this deep environment to choose an investigation question, compare technologies, and identify the evidence still needed.
Ocean Literacy Principle 7
The ocean is largely unexplored
Follow ocean exploration from questions and discoveries to collaboration, models, underwater vehicles, and connected observing systems. Evaluate what each method can reveal and what remains uncertain.
Guiding question: How do people, models, and technologies work together to investigate an ocean we cannot observe everywhere?
NMEA grade band: Grades 9–12
Other grade bands are in preparation.
At a glance
What students should take away
Students should be able to design an investigation that connects a question, a team, suitable observations, and a model, while explaining its limitations.
Learning goals
- Connect discoveries and repeated observations with resource decisions and new questions.
- Explain why ocean exploration needs different disciplines, careers, and international participation.
- Distinguish models from simulations and evaluate their uncertainties.
- Compare underwater vehicles and combine remote sensing, direct measurements, and molecular evidence.
Teach this principle
Why this matters
Decisions about ocean resources, climate, and ecosystems depend on evidence gathered across places, depths, and times. Understanding how evidence is collected helps students judge both the usefulness and the limits of ocean knowledge.
Turn a discovery into a question
- Student task
- Choose a habitat or resource and propose a testable question. Identify what a first observation could reveal and why repeated measurements may be needed.
- Ask the class
- What could one visit miss?
- Listen for
- Changes over time, rare events, and variation require repeated observations; discovering a resource does not establish its sustainable use.
Build an investigation team
- Student task
- Assign scientific, technical, communication, and decision-making roles. Explain the expertise and training each role needs and why international participation could help.
- Ask the class
- Who needs the findings, and how should the team communicate uncertainty?
- Listen for
- Different disciplines and career paths contribute; accurate, timely information supports public decisions.
Test a model’s limits
- Student task
- Use a mapped dataset or a simple circulation representation. Separate observations, model assumptions, and a simulation through time; identify missing evidence.
- Ask the class
- What would make a model more useful without making it certain?
- Listen for
- Better observations, scientific understanding, mathematical representation, and computing improve a model while uncertainty remains.
Teaching resources
Compare three underwater vehicles
- Student task
- Compare an HOV, ROV, and AUV for a chosen investigation. Consider human presence, tethering, samples, power, depth rating, duration, and support needs.
- Ask the class
- Why is no vehicle the best choice for every question?
- Listen for
- Capabilities and limits vary by design and mission; autonomy removes the tether but not energy or operational constraints.
Combine complementary evidence
- Student task
- Plan an investigation using surface imagery, a buoy or glider record, and animal-tag or molecular evidence. Explain what each contributes and how data reach the team.
- Ask the class
- Which part of your question would remain unanswered by satellite imagery alone?
- Listen for
- Surface views need complementary measurements at depth and biological evidence; satellite data transfer requires a suitable surface link.
Check understanding
What would we need to learn about an ocean place before making decisions about its use?
Explore the concepts
Exploration, discovery, and changing knowledgeConnect new questions with discoveries, repeated observations, and the consequences of using ocean resources.
Exploration generates questions and discoveries.
Exploration improves understanding of ocean systems and can generate hypotheses for further testing. New habitats and species continue to be discovered. Studying organisms can reveal connections between people and the ocean and support cancer research, new medicines, and other benefits. Many effects of human activities remain incompletely understood.
Resource use makes understanding limits essential.
The CFD describes a marked increase in ocean-resource use since 1970. Sustainable use depends on understanding resources’ potential and limitations. Technologies develop access to minerals, biological resources, and energy, including tidal power, wave power, and ocean thermal energy conversion; access alone does not establish sustainability.
Observations over time improve explanations and predictions.
Advanced instruments provide data for estimates and predictions about physical and biological processes. Repeated observations reveal complexity and changing patterns in noise pollution, weather, sea-surface temperature, and oxygen-poor dead zones. A time series can reveal changes that a single visit misses.
Connected concepts in other principles
Collaboration, careers, and communicationAsk who produces ocean knowledge, who uses it, and how participation shapes exploration.
Different skills and training contribute to exploration.
Ocean exploration connects people across countries, careers, and organizations, including universities, research institutes, government agencies, and private industries. Computer science, engineering, biology, geology, chemistry, and physics contribute data, technologies, ideas, and methods. Careers require interest and commitment, with routes through study, apprenticeships, vocational training, colleges, and universities.
Participation and communication shape decisions.
Accurate, timely communication helps the public make informed choices about ocean sustainability. Political, social, and scientific engagement at national and international levels influences opportunities, awareness, and future directions of exploration. Global participation matters because one connected ocean sustains life across borders.
Connected concepts in other principles
Models, simulations, and uncertaintySeparate a representation of an ocean system from an experiment that runs that representation through time.
Models represent systems; simulations explore their behavior.
Scientific models are physical, mathematical, or logical representations of entities, processes, and phenomena, such as ocean circulation. A simulation runs a model through time to test, analyze, or experiment with that representation. Together they help investigate interactions and interdependence without directly manipulating the whole ocean.
Models improve with evidence but retain limitations.
A model’s accuracy depends on scientific understanding, mathematical representation, the quantity and types of observations across space and time, and computing capacity. Satellites, seafloor and surface observatories, and digital communication provide extensive data, sometimes in near real time, to improve models and simulations. More data do not automatically remove uncertainty or gaps in coverage.
Ocean challenges and underwater vehiclesMatch the question and environment to the capabilities and limitations of each observing tool.
Ocean conditions demand specialized tools.
The ocean covers about 70% of Earth. Its vastness, depth, pressure, light conditions, temperature, and salinity make exploration difficult. Technologies deployed in space and underwater collect different kinds of data across places and times. Mapping the seafloor, observing a site, and understanding an ecosystem are different achievements; the 2021 CFD’s combined “less than 20%” statement is historical, not a current measure of all three.
Submersibles include human-occupied vehicles (HOVs), remotely operated vehicles (ROVs), and autonomous underwater vehicles (AUVs). Each extends access below the surface, with different strengths and constraints.
Human-occupied vehicles bring observers to depth.
HOVs carry people to observe and collect samples, usually with support from a surface vessel. They enabled discoveries such as life at hydrothermal vents. Space, life support, cost, and dive duration constrain their use. Depth limits depend on the vehicle: specially designed crewed vehicles have reached the deepest ocean, so the CFD’s blanket exclusion of that capability should not be generalized.
Remotely operated vehicles use a tether.
ROVs are underwater robots controlled by pilots aboard a ship through a cable that carries power, commands, video, and other data. Sonar, magnetometers, robotic arms, and water samplers can enable measurements, specimen collection, and experiments at depth. The tether supports direct control but constrains operations.
Autonomous vehicles follow programmed missions.
AUVs use onboard computers and power to navigate without a physical connection to an operator. Their sensors measure physical and biological features along planned missions. Freedom from a tether and onboard human life support can extend coverage and deployment time. Depth, endurance, and access to shallow areas depend on design; energy, navigation, and launch or recovery conditions still limit operations.
An AUV’s operators may be aboard a support ship or onshore. The vehicle follows onboard control underwater; any remote updates depend on available communication links.
Connected observations, from satellites to moleculesCombine complementary measurements to investigate ocean processes and inform management.
Satellites observe the surface and relay measurements.
Scientists and resource managers use observing data to study ocean and climate processes, water quality, and activities near protected areas. Satellite cameras and radiometers provide broad views and measurements of the surface; NOAA and NASA data support estimates of sea-surface temperature and productivity. Satellites also relay data from ocean instruments. Repeated coverage is valuable but is not a continuous view of every depth and place.
Fixed and moving platforms reveal different patterns.
Scientists and citizens can use records from fixed buoys to investigate daily, seasonal, and annual changes at particular locations. AUVs, including gliders, collect measurements at selected depths along planned paths, revealing surface and water-column conditions across a region. Satellite transmissions need a surface connection, such as a surfaced vehicle or a relay; satellites do not directly receive radio signals from deep underwater.
Animal tags connect movement with habitat.
Transmitters attached to animals such as elephant seals, tuna, and sea turtles can provide movement data via satellite links when transmission conditions permit. These records help scientists infer geographic ranges, distributions, habitats, and migration patterns; a tag samples the movements of particular animals, not an entire population.
Observing systems combine remote and in-place measurements.
Ocean-observing systems connect repeated measurements of Earth, ocean, and atmosphere to study interacting ocean and climate processes and human impacts. Remote sensing observes from a distance using satellite, aircraft, or land-based instruments. In situ measurements are made at the study location, using ships, buoys, gliders, and sampling devices.
Sensors, power supplies, and transmitters support the collection and transfer of observations such as salinity, sea-surface temperature, and cloud cover to computers ashore. These complementary methods provide different pieces of the system, rather than each instrument measuring everything.
Molecular and isotope methods add another scale of evidence.
DNA methods and isotope analysis provide detailed information about organisms within large systems. Combined with other evidence, they help investigate population structure, food webs, and migration. Laboratory measurements complement field observations rather than replacing them.
Teaching resources
Start here
Explore this principle with the platform
WebGIS
Compare mapped observations and model-based layers; identify their depth, time coverage, and limitations before drawing conclusions.
Sources and curriculum alignment
Grades 9–12 conceptual alignment: Adapted from NMEA Ocean Literacy Scope and Sequence under CC BY-NC-SA 4.0.
Adapted from the NMEA Grades 9–12 Principle 7 CFD (2021, handbook page 73). Five sections preserve exploration, collaboration, and technological innovation, separating models, vehicles, and observing systems. Scientific clarifications distinguish mapping from exploration and qualify vehicle limits and satellite communication. Classroom tasks and platform links are Blue Biome teaching suggestions, not activities supplied by NMEA.
Source concepts and connections
The notes below paraphrase the English NMEA source. They also explain qualified adaptations and corrected references.
A · Exploration generates questions and discoveries.
- Exploration improves understanding of ocean systems.
A1 · Exploration generates questions and discoveries.
- Ocean exploration provides opportunities that can lead to hypothesis-generated science.
A2 · Resource use makes understanding limits essential.
- Ocean-resource use has increased substantially since 1970.
- sustainability requires understanding resource potential and limitations.
Adaptation notes (English)
Attribute the resource-use baseline to the CFD; access and possible benefits do not guarantee sustainability or completed medical applications. Preserve remaining uncertainty about human impacts.
Read the explanationA3 · Resource use makes understanding limits essential.
- Developing technologies enable mineral and biological resource use and energy production, including tidal, wave, and ocean thermal energy conversion.
Adaptation notes (English)
Attribute the resource-use baseline to the CFD; access and possible benefits do not guarantee sustainability or completed medical applications. Preserve remaining uncertainty about human impacts.
Read the explanationA4 · Observations over time improve explanations and predictions.
- Advanced technology supplies data for better estimates and predictions of physical and biological phenomena.
A5 · Observations over time improve explanations and predictions.
- Data over time reveal ocean complexity and changing patterns, including noise pollution, weather, sea-surface temperatures, and dead zones.
A6 · Exploration generates questions and discoveries.
- Previously unknown habitats and species continue to be discovered throughout the ocean.
A7 · Exploration generates questions and discoveries.
- Exploring ocean organisms yields discoveries relevant to human health and ocean–human connections.
Adaptation notes (English)
Attribute the resource-use baseline to the CFD; access and possible benefits do not guarantee sustainability or completed medical applications. Preserve remaining uncertainty about human impacts.
Read the explanationA8 · Exploration generates questions and discoveries.
- Discoveries can benefit cancer research, new medicines, energy, and other human needs.
Adaptation notes (English)
Attribute the resource-use baseline to the CFD; access and possible benefits do not guarantee sustainability or completed medical applications. Preserve remaining uncertainty about human impacts.
Read the explanationA9 · Exploration generates questions and discoveries.
- Many negative effects of human activities on the ocean are incompletely understood.
Adaptation notes (English)
Attribute the resource-use baseline to the CFD; access and possible benefits do not guarantee sustainability or completed medical applications. Preserve remaining uncertainty about human impacts.
Read the explanationB · Different skills and training contribute to exploration.
- Exploration requires collaboration across careers, disciplines, countries, and organizations, including universities, research institutes, agencies, and private industries.
B1 · Different skills and training contribute to exploration.
- People with diverse international expertise propose ideas and develop exploration and research methods.
B2 · Different skills and training contribute to exploration.
- Exploration careers require interest, commitment, study, and apprenticeships, potentially through vocational schools, colleges, and universities.
B3 · Participation and communication shape decisions.
- Accurate and timely public communication supports informed decisions promoting ocean sustainability.
B4 · Different skills and training contribute to exploration.
- Ocean understanding integrates data and technologies from computer science, engineering, biology, geology, chemistry, and physics.
B5 · Participation and communication shape decisions.
- National and international political, social, and scientific engagement shapes opportunities, awareness, and future exploration directions.
B6 · Participation and communication shape decisions.
- Global participation is needed because a single ocean connects and sustains life.
C · Ocean conditions demand specialized tools.
- The ocean covers 70% of Earth.
- the 2021 sheet combines mapping, observation, and exploration in a less-than-20% estimate. Temperature, light, salinity, depth, vastness, and pressure create exploration challenges requiring technologies with strengths and limitations.
Adaptation notes (English)
Treat the 2021 combined less-than-20% statement as historical, not a current statistic. Distinguish high-resolution seafloor mapping, site observation, and ecosystem understanding; retain approximately 70% surface coverage and the physical challenges.
Read the explanationC1 · Models represent systems; simulations explore their behavior.
- Models and simulations help describe, manipulate representations of, and experiment with ocean systems to understand interactions, connections, and interdependence.
Adaptation notes (English)
Simulations run representations through time; experimenting with a model is not manipulating the entire real ocean. New data can improve models without eliminating uncertainty or providing universal real-time coverage.
Read the explanationC2 · Models represent systems; simulations explore their behavior.
- Models are physical, mathematical, or logical representations of entities, processes, and phenomena, exemplified by circulation patterns.
Adaptation notes (English)
Simulations run representations through time; experimenting with a model is not manipulating the entire real ocean. New data can improve models without eliminating uncertainty or providing universal real-time coverage.
Read the explanationC3 · Models improve with evidence but retain limitations.
- Model accuracy is limited by system knowledge, mathematical representation, data types and quantity over time and geography, and computing capacity.
Adaptation notes (English)
Simulations run representations through time; experimenting with a model is not manipulating the entire real ocean. New data can improve models without eliminating uncertainty or providing universal real-time coverage.
Read the explanationC4 · Models improve with evidence but retain limitations.
- Satellites, seafloor and sea-surface observatories, and digital media improve models and simulations by providing extensive data across space and time.
Adaptation notes (English)
Simulations run representations through time; experimenting with a model is not manipulating the entire real ocean. New data can improve models without eliminating uncertainty or providing universal real-time coverage.
Read the explanationC5 · Models represent systems; simulations explore their behavior.
- Simulations implement models over time to test, analyze, and experiment with representations of real ocean systems.
Adaptation notes (English)
Simulations run representations through time; experimenting with a model is not manipulating the entire real ocean. New data can improve models without eliminating uncertainty or providing universal real-time coverage.
Read the explanationC6 · Ocean conditions demand specialized tools.
- Tools in space and underwater gather varied ocean data across geographic locations and times.
C7 · Ocean conditions demand specialized tools.
- Submersibles collect observations below the surface, including human-occupied, remotely operated, and autonomous underwater vehicles.
Adaptation notes (English)
Keep the distinction between occupied, tethered remotely operated, and untethered autonomous vehicles. AUV depth, shallow-water access, endurance, and weather exposure depend on design and operations; autonomy is not unlimited energy or immunity to launch/recovery weather.
Read the explanationC8 · Human-occupied vehicles bring observers to depth.
- HOVs carry scientists to depth to observe and collect samples, with compact accommodations and surface-vessel support.
Adaptation notes (English)
Retain HOV sampling, hydrothermal-vent discoveries, support, cost, and endurance constraints. Correct the blanket exclusion of deepest-ocean access: Trieste carried people to Challenger Deep in 1960. Capabilities vary by vehicle.
Read the explanationC9 · Human-occupied vehicles bring observers to depth.
- HOVs enabled major discoveries, including hydrothermal-vent life.
- the box contrasts their costs, endurance, versatility, and depth limits with robotic vehicles. Its assertion that HOVs cannot reach the deepest ocean needs correction.
Adaptation notes (English)
Retain HOV sampling, hydrothermal-vent discoveries, support, cost, and endurance constraints. Correct the blanket exclusion of deepest-ocean access: Trieste carried people to Challenger Deep in 1960. Capabilities vary by vehicle.
Read the explanationC10 · Remotely operated vehicles use a tether.
- ROVs are underwater robots controlled from a ship through a tether carrying electrical power, video, and data between pilot and vehicle.
Adaptation notes (English)
Keep the distinction between occupied, tethered remotely operated, and untethered autonomous vehicles. AUV depth, shallow-water access, endurance, and weather exposure depend on design and operations; autonomy is not unlimited energy or immunity to launch/recovery weather.
Read the explanationC11 · Remotely operated vehicles use a tether.
- ROVs can carry sonar, magnetometers, robotic arms, and water samplers to gather data and specimens and conduct experiments at depth.
Adaptation notes (English)
Keep the distinction between occupied, tethered remotely operated, and untethered autonomous vehicles. AUV depth, shallow-water access, endurance, and weather exposure depend on design and operations; autonomy is not unlimited energy or immunity to launch/recovery weather.
Read the explanationC12 · Autonomous vehicles follow programmed missions.
- AUVs have onboard computer control and power and no physical operator connection.
- the sheet describes autonomous access and weather/depth advantages that require design-specific qualifications.
- AUV operators may be onshore or aboard a ship.
Adaptation notes (English)
Keep the distinction between occupied, tethered remotely operated, and untethered autonomous vehicles. AUV depth, shallow-water access, endurance, and weather exposure depend on design and operations; autonomy is not unlimited energy or immunity to launch/recovery weather.
Read the explanationC13 · Autonomous vehicles follow programmed missions.
- AUV sensors measure physical and biological ocean features.
- freedom from a tether and onboard human constraints can extend coverage and deployment time.
Adaptation notes (English)
Keep the distinction between occupied, tethered remotely operated, and untethered autonomous vehicles. AUV depth, shallow-water access, endurance, and weather exposure depend on design and operations; autonomy is not unlimited energy or immunity to launch/recovery weather.
Read the explanationC14 · Satellites observe the surface and relay measurements.
- Scientists and resource managers use observations to understand ocean and climate processes and monitor water quality and activities near protected areas.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC15 · Satellites observe the surface and relay measurements.
- Satellites collect broad-scale sensor data and relay transmissions from fixed buoys, AUVs, and animals.
- transmission and coverage limitations require qualification.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC16 · Fixed and moving platforms reveal different patterns.
- Scientists and citizens use records from fixed buoys to investigate local and regional daily, seasonal, and annual patterns.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC17 · Fixed and moving platforms reveal different patterns.
- AUVs such as gliders follow predetermined paths and depths.
- relayed data describe regional ocean-surface and water-column conditions.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC18 · Animal tags connect movement with habitat.
- Tags on elephant seals, tuna, sea turtles, and other organisms provide information about travel, ranges, distributions, habitats, and migration.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC19 · Satellites observe the surface and relay measurements.
- Satellite cameras and radiometers provide extensive surface observations.
- NOAA and NASA data help map sea-surface temperatures and productivity.
Adaptation notes (English)
Distinguish satellite sensing from relaying in-water measurements. Radio links need a suitable surface connection; do not imply direct satellite reception from deep underwater. Repeated large-scale coverage is not observation of every depth and location. Tag data concern sampled animals.
Read the explanationC20 · Observing systems combine remote and in-place measurements.
- Ocean-observing systems supply sustained Earth, ocean, and atmosphere data to study ocean–climate interactions and human impacts.
Adaptation notes (English)
Define remote and in situ sensing by measurement location. The listed variables are collected across complementary instruments, not by every sensor. DNA and isotope analyses complement field data and support inference rather than directly revealing every population or food-web property.
Read the explanationC21 · Observing systems combine remote and in-place measurements.
- Observing systems combine remote sensors on satellites, aircraft, and land with in situ platforms, including ships, buoys, gliders, and sampling devices.
- power and transmission systems deliver varied measurements to shore computers.
Adaptation notes (English)
Define remote and in situ sensing by measurement location. The listed variables are collected across complementary instruments, not by every sensor. DNA and isotope analyses complement field data and support inference rather than directly revealing every population or food-web property.
Read the explanationC22 · Molecular and isotope methods add another scale of evidence.
- Molecular methods, including DNA technology and isotope analysis, provide detailed organism evidence for population structure, food webs, and migration in large systems.
Adaptation notes (English)
Define remote and in situ sensing by measurement location. The listed variables are collected across complementary instruments, not by every sensor. DNA and isotope analyses complement field data and support inference rather than directly revealing every population or food-web property.
Read the explanationConcept pathways (English)
Exploration, discovery, and changing knowledge: Connect new questions with discoveries, repeated observations, and the consequences of using ocean resources.
Collaboration, careers, and communication: Ask who produces ocean knowledge, who uses it, and how participation shapes exploration.
Models, simulations, and uncertainty: Separate a representation of an ocean system from an experiment that runs that representation through time.
Ocean challenges and underwater vehicles: Match the question and environment to the capabilities and limitations of each observing tool.
Connected observations, from satellites to molecules: Combine complementary measurements to investigate ocean processes and inform management.