Baltic Sea

Ten years since the sampling in the Baltic Sea started – how we learn more about the sea

This year, 2021, researchers at Linnaeus University have collected water samples from the Baltic Sea for a decade, at least biweekly – at times weekly. So, why is this important? Long time-series of research data with information about the microorganisms that live in water teach us about the sea and how it is changing. The collected data can help us gain a better understanding of how the Baltic Sea is doing and make predictions of the future.

Since 2011, samples have been collected more than 340 times at the sampling station called Linnaeus Microbial Observatory (LMO), to study, among other things, water chemistry, bacteria, and plankton in the Baltic Sea. The sampling series has contributed to knowledge about how vitamins are produced by microorganisms in the sea. Vitamins, such as vitamin B1 are vital to zooplankton as well as to fish and seabirds.

Now, after ten years of sampling, the researchers are summing up the different data sets. The water samples provide information about a number of different parameters. For instance, temperature, salinity and nutrient concentration in the water. The researchers also study the composition of species and the microbial life, like bacteria and plankton.

“All small organisms, what we call the microbial community in the water, play an important role in the Baltic Sea ecosystem. By using data from the water samples, the researchers can see how changes and seasonal dynamics take place in the Baltic Sea during a longer period of time. Water samples from one single year do not tell us much about how the Baltic Sea, or any environment, changes over time. Therefore, these longer time-series of data are incredibly valuable”, explains Hanna Farnelid, associate professor in marine ecology.

The sampling station is located 11 kilometers off the coast of Kårehamn on the island of Öland, with an associated field lab on land. Several research groups are active here, conducting research in marine ecology and microbial oceanography. However, LMO is, to an equal extent, a cross-community project where, for instance, the company RWE Renewables helps with access  to the sampling station, and the research collaboration extends to Stockholm, Spain and Germany.

Can the sampling tell us about the future or past of the Baltic Sea?

“One of the main goals of the research is to investigate what we can predict about the future of the Baltic Sea and what changes will occur in the marine ecosystem. For instance, the summer of 2018 was an unusually warm summer and we could see that there was a higher occurrence of certain species of microorganisms in the water. With such long series of data, we have the ability to make better assessments of the changes that will occur in  the future. The distribution and abundance of some species will likely increase while other species will disappear”, Farnelid continues.

In what way is the sampling important for research at the Linnaeus University and in Sweden?

“What is unique about LMO is that we specifically study the microbial community of the Baltic Sea, with a focus on both the species composition and functions. In this way, we get to know the Baltic Sea in a new way. The next step is to study how microbial processes interplay with other organisms in the food chain and the ecosystem. That is why I think the LMO sampling is an important and very exciting project!”, Farnelid concludes.

More information

Linnaeus Microbial Observatory (LMO) is part of Linnaeus Knowledge Environment: Water. The purpose of the knowledge environment is to collect and spread the knowledge required for understanding how best to handle our planet’s water resources in a sustainable way.