Welcome to the OAO Frequently Asked Questions. Here you will find answers to the common questions asked.

Do ships often collide with undersea robots?

The OAO team is not yet aware of any incident of this kind. The risk of being bumped into by ships also seems limited since the surface interval is rather short. Moreover, especially in case a larger ship shall be approaching a surfacing robot, it is assumed that the bow wave would wash the robot aside.

Do fishermen occasionally have an undersea robot as bycatch?

Once in a while it happens that fishermen discover an undersea robot within their nets. On both gliders and profiling floats, a sticker identifies them as scientific instruments and gives contact details. The finder is asked to inform the operating team so that action can be taken in order to bring the undersea robot safely back to the laboratory.

Is bio-fouling affecting profiling floats?

Between each vertical profile the floats park in cold, dark and deep waters. Under these conditions only little fouling is expected to occur on the instruments and their sensors.
First return information on multi-year experiences indeed suggest that the deployment of optical sensors on profiling floats is highly effective for producing long-term records with little or no effect of bio-fouling. Especially in case the sensors are looking downwards and are mounted on the uppermost part of the float, each surfacing allows the sensor to be flushed when passing the ocean-air interface.
Moreover surface residence time and hence bio-fouling risks can now be minimized thanks to iridium telemetry (as compared to Argos telemetry). But, since lifetimes for floats and sensors are expected to increase, still specific solutions are needed. It therefore remains highly desirable to continue in developing and testing procedures aiming at preventing and/or diminishing bio-fouling.

What happens to a profiling float at the end of its mission?

The mission of a profiling float ends when the batteries of the undersea robot become too low in energy to sustain the function of pumps, valves and sensors. Since profiling floats surface at regular intervals to transmit data, indications of low energy levels reach the scientists usually in time to take their decisions.
At first a change in parameters may be envisaged to save energy for specific observations during the rest of its lifetime drifting with the currents. It may also be decided to stop the mission on either point of its vertical move. Stopping a mission at sea surface in some cases allows to recover the profiling float and with it precious information for further developments e.g. on bio-fouling and corrosion of technical components. When recovery is not possible and to avoid accidents e.g. with ships, the mission is ended within the water column to allow the instrument to sink to the bottom.

Do profiling floats pollute our Seas?

Equipped with non-intrusive sensors and emitting little noise only, a profiling float does not pollute the marine environment during its mission. However, at the end of a mission and in case the undersea robot cannot be recovered, it sinks to the sea floor. This implies a risk of contaminants seeping into the environment along with its gradual degradation. The potential impacts seem acceptable given the unique oceanic observations acquired by profiling floats. Such observations and their scientific outcome are necessary to better understand the Ocean functioning within a context of environmental change and to prepare for future.
If possible, scientists of course try to recover the profiling floats not only to avoid pollution but also in order to analyze their technical components and so to contribute to their development. A possibility of recovery of the instruments is higher in regional Seas and coastal areas. In remote oceanic areas and the open ocean the efforts needed and exceeding costs (e.g. using a research vessel) usually do not balance the possible damage.
Moreover, scientists together with scientific engineers work on alternative systems to power the profiling floats in more environmental-friendly ways.

Why gliders are yellow?

There is no particular reason and there are gliders that are orange or pink as well. It is however important that the color should be easily visible particularly in bad weather conditions in order to facilitate recovery.

Why gliders have names such as "Tintin" or "Milou"?

These are the OAO "given names" inspired by figures appearing in the series of comic strips called "Adventures of Tintin". Tintin, a young reporter, is aided by his faithful fox terrier Snowy, or Milou for French readers. … While these names are usually used within the context of OAO actions in order to facilitate every day handling, all undersea robots also have international identification numbers.

Is Argo equal to Argos?

No. Argo (without "s") refers to the international program operating about 3000 profiling floats. These measure temperature and salinity, and when surfacing transmit their collected data through the Argos (with "s") transmission system.

What is the data is primarily used for?

Routinely measured data together with their rapid transmission and dissemination is particularly useful in terms of operational oceanography. Such real-time data are indeed used to generate products like forecasts of the Ocean state (e.g. oceanic currents). They also are used for risk management as e.g. in the case of the Deepwater Horizon oil spill in the Gulf of Mexico or in order to determine the propagation of radioactive pollutants after the Fukushima accident. In the near future, warnings of high jellyfish abundances that drift ashore are also expected. These "real-time" products include first scientific interpretations and need to be rapidly available for the end-users (e.g. industrial companies, governments and other authorities). So, with this "client-driven" purpose and the practical issues addressed, the data can be used for applied research.
Moreover, and after the data have undergone further quality controls, they are used to advance our fundamental knowledge and understanding of the Ocean. Such fundamental research is essential to address still open questions relevant e.g. to climate-related issues like heating of the Oceans or, more recently, like the impact of climate change on biogeochemical processes and potential feedbacks.