The developments of NeXOS are based on an integrated strategy for ocean monitoring. Several sensor systems will be developed, tested and validated for specific technologies and monitoring strategies (i.e. ocean optics, ocean passive acoustics, and EAF monitoring), and will provide an integrated, coherent system for multi-scale, multi-parameter monitoring of the oceans. This will give great potential for synergies.
Some examples are provided below, these and others will be further studied in an early stage of the project to optimise requirements:
- Optical sensor systems can measure chemical compounds and biologically relevant parameters, such as nutrients, dissolved gases, acidity and organic matter. Nutrients and dissolved oxygen are particularly relevant to fisheries management as they have a fundamental role in the production of phytoplankton, at the base of the trophic chain.
- Passive acoustics used for noise and marine mammal acoustics, also have potential in the detection of fish reproduction areas (descriptor 3 of the MSFD, and a contribution to the CFP) and the non-lethal mitigation of catch depredation by whales in fisheries activities.
- The Ecosystem Approach to Fisheries (EAF) sensor system will add chlorophyll and oxygen to the currently collected data on fish, fishing vessel activity, salinity, temperature and depth. The improvements made by NeXOS in the compactness and multifunctionality of optical sensors and passive acoustics sensors will be assessed for integration on the EAF sensor system, for the monitoring of depredation from marine mammals.
While sound travels over large distances in the ocean, light is absorbed at short distance and cannot be used for passive underwater remote sensing in practice. In contrast to ocean optics, passive acoustics can be used to measure a range of variables and can be used for remote sensing at geographic scales from meters to hundreds of kilometers. Acoustic techniques are therefore complementary to optics in multidisciplinary ocean observing systems for scanning the ocean at a distance.