Skip to main content

Remotely sensed biogeochemical cycles in the ocean

Final Report Summary - REMOCEAN (Remotely sensed biogeochemical cycles in the ocean)

The Ocean is undergoing increasing stress: becoming warmer, more acidic and less oxygenated. The remOcean (REMotely sensed biogeochemical cycles in the OCEAN) project aims to observe and understand the functioning of the biological ocean thanks to a new class of robotic profiling floats. remOcean dedicated most of its initial three first years to the technological development and the validation of these profiling floats. Besides the “classical” measurements of temperature and salinity, the remOcean floats now allow a complete suite of environmental, biological and chemical parameters to be measured between the ocean surface and 1 km depth. These new measurements include in particular:
• The Chlorophyll concentration, a proxy of phytoplankton (vegetal) biomass in the ocean
• The nitrate concentration, an essential nutrient for phytoplankton growth
• The oxygen concentration which is produced by phytoplankton photosynthesis
• The intensity of light penetrating into the ocean at different wavelengths (color), including UVs
• The backscattering coefficient, a proxy of the number and size of particles.
These new floats use iridium two-way telecommunication allowing real-time transmission of large amounts of data from the float to the lab as well as a remote control of float mission to adapt the float measurement strategy to scientific needs.
During the second phase of the project, 53 floats were deployed in various open-ocean areas like the sub-tropical Atlantic (North and South), the sub-tropical Pacific, the sub-polar Atlantic, the Indian sector of the Austral Ocean and the Red Sea. These floats have monitored oceanic properties over periods sometimes exceeding 3 years (some floats are still active, see: In parallel, procedures required for performing automatic quality control of data and their free distribution to the community were developed and organized. The resulting and still-ongoing dataset is unique with long continuous time series acquired for several key, yet poorly-known oceanic areas. The analysis of this dataset provides a better understanding of the mechanisms and processes driving the intensity of phytoplankton photosynthesis and resulting export of produced material into the deep ocean. This improved understanding represents an important prerequisite to quantifying how the ocean can possibly intervene in mitigating the sequestration of CO2 of anthropogenic origin. Furthermore, these analyses are conducted in close synergy with the observation of Ocean color measured by satellite at the ocean surface allowing, for the first time, to obtain a three-dimensional view of the upper ocean for essential oceanic variables (e.g. Chlorophyll, backscattering). It is remarkable to note that the uniqueness of the collected data as well as their free open-access will continue to foster data analyses and will ensure the longevity of the remOcean project well after its official end.
Finally, the floats deployed as part of remOcean are the support for an innovative outreach and educational activity. The concept “adopt a float” has been developed in close partnership with teachers and school authorities. Some classes are now following the scientific journey of a float. In parallel we have developed a web site to provide educational resources to better understand the oceanic features seen during “float travel” (see: