The ocean provides us with food and raw materials, as well as vital transport routes and opportunities for leisure activities; however, it is under pressure from climate change and pollution. Sustainable ocean management that relies on detailed, continuous monitoring of the marine environment is urgently needed. Water samples are normally taken from the ocean and analysed in land-based laboratories, but this approach is costly and provides a mere ‘snapshot’ in time and space.
The EU-funded SenseOCEAN project brought together leading developers of marine sensors from academia and industry to create a reliable, accurate, and cost-effective solution to deal with the challenge of ocean monitoring.
The consortium developed a range of miniaturised chemical, electrochemical and optical sensors, including a lab-on-a-chip sensor. They harmonised their function with common interfaces, plugs and connectors, and standard data formats to produce a multifunctional, in situ marine biogeochemical sensor package.
‘Combining new technologies such as 3D printing and new techniques for microfabrication enables us to ensure cost-effective mass production,’ says project coordinator Professor Douglas Connelly.
The integrated sensor packages underwent thorough field testing in the Kiel Fjord, Germany, and the Mediterranean Sea. Scientists also deployed a fast repetition rate fluorometry sensor for 150 days in the Arctic and a multi-parameter nutrient sensor for over two years in a harbour in the United Kingdom.
A nitrous oxide (N2O) electrochemical microsensor is already in use at over 100 wastewater plants, while the monitoring ability of optode sensors that use light to detect and measure specific substances in a sample have been demonstrated at fish farms.
One of the project partners developed the V-Lux multiparameter fluorometer, which can be used for monitoring environmental pollution, algae, sewage and bathing waters, oil spills (including road and airport apron run-off) and point source pollution.
It can also monitor coloured dissolved organic matter to assess organic load, coagulation control and filter management in water processing plants, and exhaust gas scrubber wash water.
The sensor package and individual sensors are easily mounted on underwater vehicles, moorings and floats, or frames in the deep sea, and used to conduct environmental analysis.
By attaching sensors to gliders large areas may be covered, while autonomous platforms can conduct frequent analyses over the long term. ‘Special protection systems are used to reduce biofouling, enabling the sensors to be deployed below the waves for long periods of time,’ explains Prof. Connelly.
Production costs for sensors were significantly reduced by minimising the number of machine parts and through the adoption of new materials and technologies, such as 3D printing, and flexi-rigid printed circuit boards.
Techniques like analogous fluidic circuits were also adopted from other fields like digital electronics, in order to reduce the number of stepper motor syringe pumps for the lab-on-a-chip.
SenseOCEAN was the first to integrate multiple sensors into one ‘plug and play’ sensor package. Furthermore, the sensors were all developed by project partners rather than simply repackaging existing ones. According to Prof. Connelly:
‘Our SME partners are already benefitting from SenseOCEAN with their products now on the market, including a field data logger and N2O microsensor, a multiparameter fluorometer; other products such as optodes are currently very close to market. The key to the success of this project was the effective collaboration between science and industry.’
In the long term, regulatory and monitoring organisations will have a new set of tools that will allow effective legislation and controls for protecting the marine environment.
‘They will also support research by enabling greater spatial and temporal sampling of the oceans, thereby increasing understanding of marine processes like ocean circulation and nutrient cycling at both local and global scales,’ concludes Prof. Connelly.