The ocean covers over 70% of Earth’s surface, a vast frontier marine scientists explore using sophisticated tools. These instruments gather data, make observations, and unravel ocean mysteries, providing insights into ocean processes, marine life, and human impacts on ecosystems.
Stationary and Profiling Ocean Instruments
Scientists deploy instruments that remain fixed or move vertically through the water column. Conductivity, Temperature, Depth (CTD) profilers measure seawater conductivity (salinity), temperature, and pressure (depth). These measurements provide insights into water column properties, aiding understanding of ocean stratification and circulation patterns. CTDs are typically lowered from research vessels, collecting continuous data during descent.
Oceanographic buoys provide continuous, long-term data collection. They can be moored to the seafloor or drift freely, carrying sensors for temperature, salinity, current speed, wave height, and atmospheric data. Current meters, often on buoys or fixed moorings, measure ocean current speed and direction. This data helps study ocean circulation and the transport of heat, nutrients, and marine organisms.
Profiling floats, such as those in the Argo program, are autonomous instruments. These untethered devices drift with currents, periodically diving to 2,000 meters and ascending to the surface. During ascent, they collect temperature and salinity profiles, transmitting data via satellite upon surfacing. This network provides a consistent, global view of ocean conditions over long periods.
Mobile Underwater Research Platforms
Remotely Operated Vehicles (ROVs) are uncrewed submersibles tethered to a surface vessel, controlled by onboard operators. Equipped with cameras, lights, and manipulator arms, ROVs allow for visual inspections, sample collection, and sensor deployment in specific underwater locations. They provide scientists with a real-time view of deep-sea environments too hazardous or deep for human divers.
Autonomous Underwater Vehicles (AUVs) are untethered, pre-programmed robots that operate independently. These vehicles map the seafloor, survey marine habitats, and collect oceanographic data over large areas. AUVs undertake long-duration missions, gathering extensive datasets for bathymetry (seafloor mapping) and environmental monitoring. Their autonomous operation makes them effective for exploring remote or vast ocean regions.
Underwater gliders are energy-efficient AUVs designed for long-duration missions. They move by altering buoyancy, gliding vertically and horizontally over vast distances. Gliders collect temperature, salinity, and other data, transmitting information upon surfacing. They are useful for sustained monitoring across ocean basins or where traditional research vessels are impractical.
Manned submersibles play a unique role in marine science. These vehicles carry human occupants, allowing scientists to directly observe and interact with deep-sea environments. They provide direct human observation, enabling researchers to make on-the-spot decisions and conduct experiments in extreme deep-sea settings.
Remote and Surface Monitoring Technologies
Satellites orbiting Earth play a role in global ocean observations. They measure sea surface temperature, ocean color (indicating phytoplankton concentration), sea level changes, and ice cover. Satellite data provides consistent, broad coverage, allowing scientists to track large-scale ocean patterns and climate-related changes.
Drones (UAVs) offer localized observation. These aerial platforms monitor marine mammals, map coastal areas, and observe near-surface phenomena with high resolution. Drones provide a flexible, cost-effective way to gather visual data and deploy small sensors.
Ship-based sonar systems use sound waves to map the seafloor and detect objects or organisms. Multibeam sonar sends multiple sound beams to create detailed, high-resolution maps of seafloor topography. These systems aid in understanding underwater geology, identifying hazards, and locating marine habitats.
Acoustic receivers and hydrophones listen to sounds in the marine environment. Hydrophones detect marine mammal vocalizations, fish sounds, and human-made noise. Acoustic receivers, used with tagged animals, track movements and behavior without direct observation.
Sampling and Collection Gear
Marine scientists use specialized gear to collect samples for laboratory analysis. Various nets collect marine organisms. Plankton nets, with fine mesh, gather microscopic plankton, foundational to marine food webs. Trawls, larger nets for different depths, collect fish and invertebrates for biodiversity and population assessments.
Grabbers and corers collect seafloor sediment samples. Grabbers scoop surface sediments, while corers extract cylindrical sections, providing a layered record of geological history, benthic organisms, and pollution. These samples offer insights into past environmental conditions and current seafloor ecosystems.
Water samplers, such as Niskin bottles, collect discrete water samples at specific depths. These bottles close remotely at predetermined depths, allowing scientists to obtain water from precise locations. Collected samples are analyzed for chemical properties like nutrient concentrations, oxygen levels, and pollutants.
Environmental DNA (eDNA) sampling assesses biodiversity without direct observation or capture. Scientists collect and filter water samples to extract genetic material shed by organisms (e.g., skin cells, waste products). Analyzing eDNA detects species present, offering a non-invasive method for biodiversity assessment and tracking marine life distribution.