(Text: Tim Schröder, Science Journalist / English Translation: Anupa Srinivasan)
Experts from the Institute of Coastal Research have equipped many commercial shipping vessels and ferries in recent years with automatic measurement devices for analysing seawater – the FerryBoxes. This measurement technology has meanwhile also been established in other countries. The data reveals not only the water quality but also allows conclusions to be drawn on how climate changes alter the marine environment. The measurement values from all over Europe are merged at a data centre in Geesthacht.
When you watch a cargo ship floating by on the Elbe, you might think of distant coasts and ask yourself where the ship is heading or what it’s carrying on board. The fact that the cargo ship could also be traveling for the sake of science is not usually the first thought to come to mind. However, cargo ships and ferries as well as cruise ships on their daily travels constantly collect scientific data in the Baltic Sea, the North Sea, the Mediterranean Sea and even between Denmark and Iceland. The vessels’ engine rooms house measurement cupboards the size of refrigerators – the FerryBoxes – which take water samples via a fully automated process and then analyse them.
“The commercial vessels serve as a virtual research platform for us,” says Dr Wilhelm Petersen, measurement technology specialist at the HZG’s Institute of Coastal Research. “They’re always traveling the same routes, which allows us to determine precisely how the water properties change along the routes or over the course of time.” This is how Petersen and his colleagues obtain scientific data delivered to their doorstep.
More than thirty ships
The FerryBox technology has been in use for a good fifteen years. More and more ships have been equipped with the devices over time. Initially only a few ferries were supplied with the devices. They are now utilised mainly on commercial vessels. Up to ten FerryBoxes are operating under the direction of Petersen and his staff. There are thirty to thirty-five systems across Europe operated by research colleagues in Finland, Norway, Italy, France and other countries.
The FerryBoxes are high-tech systems that have been developed by Petersen and his colleagues in cooperation with a firm. The devices suck in water via their own inlet in the ship’s hull and pump this water through a type of measurement obstacle course, where several sensors or analytical devices are located. These devices measure the water’s temperature, salinity and oxygen content in addition to the quantity of chlorophyll – the plant pigment that indicates the amount of algae in the water. The quantity of dissolved carbon dioxide as well as the degree of acidity in the water – the pH value – are also measured.
This technology has it all. While fresh water is continuously pumped from the sea through the pipe, the devices carry out measurements every twenty seconds. Twenty seconds for a large vessel with a cruise speed of 10 to 15 knots correspond to a cruise distance of around 100 to 150 metres, which is an exceptionally high resolution. This is how a FerryBox alone provides data with approximately six thousand measurement points on a stretch from the Norwegian city of Moss to the English North Sea harbour of Immingham. With the help of GPS, the FerryBox logs the precise coordinates for each measurement point.
Data Centre in Geesthacht
Via mobile phone communication, the FerryBox sends the measurement data gathered during the journey to Geesthacht when the ship reaches the harbour. Wilhelm Petersen and his colleagues at HZG have established an ingenious FerryBox database in recent years. The measurements transferred by mobile phone link are automatically integrated into the database, so they don’t need to be recorded or sorted manually. The system can also evaluate the data automatically. It checks each individual value as to whether it is a plausible result. If an air bubble sneaks its way into the FerryBox tubes during the journey, the measurement instruments might deliver values that don’t make sense. The database algorithms therefore assign each value with what is known as a quality flag, which is a kind of tag or a seal of quality. Petersen points out: “We therefore ensure from the start that only reliable values are used for later analysis.“
The FerryBox database has won over many research colleagues in other European countries: they also send their own FerryBox data to Geesthacht for archiving. “Some research groups, on the other hand, would prefer to save their data in their own systems and don’t like to give it away,” says Petersen. “But altogether, you could say we have since become a kind of European FerryBox centre.”
Water analysis all over the world
Not only in Europe is Wilhelm Petersen active. A FerryBox has also been tested in China. It has been used for some time now on a research vessel. A FerryBox is also planned in Chile, where it will be installed on a ferry traveling in the Patagonian fjords. It will have two objectives. On the one hand, it is to measure the extent to which aquaculture is polluting the fjords there. On the other, climate change is more heavily visible at the very southernmost regions of the South American continent than elsewhere. The Patagonian glaciers are melting. At the same time, the water seems to be acidifying. The FerryBox measurement values are to be used to study how these two factors affect the aquatic habitats.
“Initially we mainly measured physical and oceanographic parameters, such as temperature, salinity and oxygen content,” says Petersen. “During the course of climate change, however, pH values or the quantity of dissolved carbon dioxide in the water is what has become primarily decisive. We have therefore increasingly expanded the FerryBoxes by using new or more sensitive measurement technology.”
The great advantage of installation on a ship is that the measurement technology is well protected and there is sufficient energy supply. With measurement equipment installed on buoys or in underwater vehicles, the researchers must always ensure that the capacity of the on-board batteries is sufficient. This limits use of the equipment. The FerryBox is also self-cleaning, Petersen points out. To ensure that the tubes and sensors don’t become overgrown with bacteria, algae or barnacles, the FerryBox cleans the tubes with fresh water or compressed air at every stop in the harbour. This is not possible with measurement buoys or similar equipment.
A great deal of data for scientific publications
The scientists at the Institute of Coastal Research have gained interesting insights over the course of time. This is how they can now say, with relative accuracy, when and under which conditions algae bloom in the North Sea. In a recent issue of the scientific journal Limnology and Oceanography, they show that the biological processes in the Wadden Sea and the exchange of biochemical substances between sediment, water, land and atmosphere apparently counteract ocean acidification.
The Wadden Sea acts as a type of natural bioreactor in which the organic matter is converted and thereby produces acid-binding carbon components that are also transported into the North Sea. This increases the uptake capacity for carbon dioxide from the atmosphere in the North Sea. These regions, therefore, act as a carbon sink for carbon dioxide. The basis for this knowledge is FerryBox data from the Hafnia Seaways, a cargo ship that regularly commuted between Cuxhaven and Immingham.
Because the FerryBoxes on the ships are supplied with sufficient electrical power and fresh water, they can be expanded in almost any manner. For example, the researchers are considering taking water samples and investigating them for microplastics. Another idea for the future is to supplement the instruments with DNA or gene sensors, with which the researchers can determine which plankton organisms are present in the water. This could, for example, detect toxic algae, which can form harmful algal blooms (HABs) in some marine regions. These appear in areas, such as the Chinese coastal regions, which are overly fertilised with nutrients.
The FerryBoxes are, however, already exceptionally sophisticated and fascinating with their current measurement technology equipment. Anyone wishing to see them in action can do so on board a vessel such as Mein Schiff 3. The cruise ship has an informational terminal on which you can read the measurements the FerryBox is currently carrying out. Norwegian research colleagues are equipping the Norwegian Hurtigruten AS cruise operator’s new ship, the Roald Amundsen, with a FerryBox. It will, however, not travel in Europe, but in the region around the Antarctic. In terms of climate change, however, its measurements are likely to be of particular interest.
==> When Ferries become Research Vessels (video on youtube)