Since our last update on November 4, the infiniTE™ float has completed 155 additional profiles and is now entering the Florida Straits, a narrow, high-energy corridor between the Florida Keys and Cuba where Gulf waters accelerate toward the Atlantic. The straits present markedly different sampling conditions: sharp frontal boundaries between water masses and rapidly varying subsurface structure to 800 m depth.

Current mission totals

• Profiles completed: 315

• Profiling depth: 800 meters

• Total Energy harvested: 2.609 MJ

• Sampling interval: ~every 6 hours

• Data transmission: near real-time via satellite after each surfacing

The Florida Straits sampling context

The Florida Straits form a narrow, deep passage connecting the Gulf of Mexico to the Atlantic Ocean between the Florida Keys and Cuba, concentrating both flow and vertical structure over a short horizontal scale.

Geometry: At the narrowest point, the straits are ~93 miles (150 km) wide yet exceed 1,800 m in depth, creating a confined deep channel between shallow coastal shelves. This geometry funnels flow and steepens horizontal and vertical gradients in temperature and velocity.

The Florida Current: The Florida Current accelerates as it exits the Gulf, with mean surface velocities of 4–6 mph (6.5–9.5 km/h). These speeds increase horizontal advection between profiles and sharpen frontal boundaries encountered during repeated sampling.

Long-term monitoring: Current transport through the straits has been monitored nearly continuously since 1982 by NOAA's Atlantic Oceanographic and Meteorological Laboratory, producing over 14,000 daily transport estimates. This long record provides a well-characterized dynamical context for new subsurface observations.

From Gulf drifting to boundary-current sampling

For its first 315 profiles, the float drifted across the Gulf of Mexico, building a broad picture of subsurface temperature and salinity conditions.

In the Florida Straits, the situation changes. Strong currents carry the float tens of kilometers between profiles, and water properties can change quickly over short distances. This means each profile reflects not only changes over time, but also differences from one location to the next.

Compared with the interior Gulf, these faster currents and sharper boundaries make the Florida Straits a more challenging environment to sample and interpret, requiring frequent, repeated measurements.

What’s being measured every cycle

Every ~6 hours the float dives, profiles, surfaces, and transmits data.

CTD (Conductivity–Temperature–Depth): Profiles salinity and temperature through the upper ocean to reveal layering, mixing, and subsurface heat structure—information satellites cannot observe.

Hydrophone: Records the underwater soundscape. Onboard processing compresses acoustic data for near-real-time transmission via satellite.

How it’s powered (no battery replacement required)

infiniTE™ is powered by Seatrec’s thermal energy harvesting system using phase-change materials (PCMs). As the float cycles between warm surface water and cold deep water, the PCM expands and contracts during phase transition, driving a hydraulic system and generator to produce electricity.

This enables sustained operation at approximately four profiles per day over multi-month deployments without battery replacement.

Collaboration opportunities

Seatrec is seeking collaborators focused on:

• Subsurface heat transport and model validation
• Gulf/Florida Straits soundscape ecology
• Long-duration autonomous sensing

Interested in data access or deploying similar technology? Contact info@seatrec.com.