Understanding the interactions between the sea and the atmosphere is becoming an increasingly important part of climate research. Climate change affects the coastal zone through warmer waters, worsening eutrophication, and more frequent algal blooms. But the influence also runs the other way: coasts can affect the climate by releasing greenhouse gases and aerosols into the atmosphere.

To investigate these complex interactions more effectively, Stockholm University’s Askö Laboratory has built a new floating laboratory equipped with a wide range of instruments.

“We identified the need for a platform where we could make simultaneous measurements in both air and water,” explains Matthew Salter, staff scientist at the Baltic Sea Centre. “It needed to stay in place for long periods, so we could capture different weather conditions and seasons, and it also had to function in very shallow waters.” 

These requirements led to the construction of a container-equipped platform, brought to Askö Island about a year ago. Since then, it has been gradually fitted with instruments that are now operational.

“It has taken time to procure all the parts and install the instruments,” says Salter. “But I’m happy to say that it is now up and running, even though there is still more to add,” 

Measurements in air and water

The floating laboratory carries a suite of instruments that measure greenhouse gases in both air and water with high precision. A chemical ionisation mass spectrometer determines volatile organic compounds (VOCs), gases that can condense to form airborne particles, in the air and, soon, in the water using a segmented flow coil equilibrator.  

Within days, a large floating sea spray simulation chamber will be connected to the platform. This chamber will make it possible to generate fresh sea spray aerosol particles in situ, without interference from other particles already present in the coastal atmosphere. In this way, researchers will be able to isolate the processes driving sea spray formation and better understand the role these particles play in the coastal climate system. 

"VOCs are important because they can form aerosols that generally cool the climate by scattering sunlight and promoting cloud formation," explains Matthew Salter. 'They also influence air quality and human health. Yet the release of VOCs from the sea remains one of the least studied areas of climate research.”

These chemical measurements are complemented by observations of more basic parameters, such as temperature and salinity, helping to link emissions of greenhouse gases and VOCs to biodiversity and ecosystem conditions. For example, earlier studies suggest that eutrophication can enhance the release of methane, a powerful greenhouse gas. 

A FlowCytobot, soon to be installed alongside the platform, will continuously monitor microscopic phytoplankton in the water, providing detailed information on how the plankton community changes over time.
“Each instrument is powerful on its own,” says Salter “but together they allow us to piece together a much bigger picture of the complex processes along our coasts.”

Available for all researchers

The new platform will be particularly valuable for researchers within CoastClim – a collaboration between Stockholm University Baltic Sea Centre, the Bolin Centre for climate research, Tvärminne Zoological Station, and the University of Helsinki’s Institute for Atmospheric and Earth System Research (INAR). CoastClim brings together more than seventy researchers from diverse disciplines, such as marine ecology, biogeochemistry and atmospheric science, all working to better understand how coastal processes influence the climate.

“But as part of Stockholm University’s research infrastructure, the floating laboratory is open to all researchers interested in these questions,” says Matthew Salter. “Through collaboration, we can better understand these complex processes and reduce the uncertainties surrounding the role of coasts in the climate system.”

Text: Lisa Bergqvist