Saving the Baltic Sea

Latest update November 21, 2018 Started on November 12, 2018

The Baltic Sea is suffocating. It is gasping for air after hundreds of years’ worth of human activities pouring into agricultural waste and sewage. A body of water that serves nine countries and 85 million people, the Baltic Sea is one of the most polluted in the world. All of the excess nutrients that have poured into it over the past few hundred years have caused an overgrowth of microalgae, a phenomenon known as eutrophication. In some areas, the degradation of bacteria has led to “dead bottoms” - zones with virtually no oxygen at all. With climate change on the horizon, it is only predicted to get worse.

But alas, the State of the Baltic is not entirely bleak. Teams of marine biologists from many of Sweden’s leading universities are studying the Baltic Sea, starting from the bottom up, to see how it will react to climate change. Some researchers, including our team at Linnaeus University in Kalmar, are working with local industries and municipalities to start cleaning up the sea. At LNU, we focus on marine bacteria, phytoplankton, and zooplankton in the Baltic Sea to determine how it will react to climate change in the future. We analyze changes in the food web, starting with tiny microscopic plants up to fish and birds to see how every organism will fare in the future. And twice weekly we sample the water in the Baltic Proper, rain or shine, off the windy coast of the island of Öland, at the Linnaeus Microbial Observatory. Data gathered at the LMO is a major player in increasing our knowledge about the Baltic Sea, and what we can do to save it.

November 12, 2018
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The Baltic Sea is suffocating. It has had too much of the good stuff for too long. And I’m not talking about fast food as we know it. I’m talking about people and industries pouring agricultural runoff and sewage into the sea for years. These high nutrient inputs cause overgrowth, a phenomenon known as eutrophication. The nutrients work as food for microscopic algae , causing them to increase in numbers. More algae leads to a higher consumption of oxygen. Without oxygen, very few organisms can live. So what should we do about it? The Algoland recovery project is working on one way to decrease nutrient inputs to the Baltic Sea.

In rain or shine, the Algoland sampling crew dons their work gear and heads out in a car filled with sampling bottles to a greenhouse located at a local power plant, Kalmar Energi. There, three “raceway ponds” which, to the casual observer may look like strange algae-filled bathtubs, help the team to do important work in the field of sustainability.

Dried algal biomass Kalmar Energi, a local power plant, provides the gas (carbon dioxide) for growing microalgae Good morning Moskogen! Team Algoland member Maurice Hirwa surveys the raceway ponds Paddle wheels constantly churn the algae filled water in the raceway ponds, allowing for photosynthesis to occur Tiny, unicellular aquatic plants called microalgae are grown in these raceway ponds to treat wastewater that leaks out from the nutrient-heavy landfill nearby (owned by waste management company KSRR). As a bonus, carbon dioxide, a waste product from Kalmar Energi’s heat production, is bubbled into the raceway ponds to boost microalgal growth. By using the natural ability of microalgae to take up nutrients and carbon dioxide, we can help industries to clean their wastewater and their greenhouse gas emissions.

But Swedish climate is not always as nice as in the post cards. In fact, most of the time it’s not. And this of course has implications for growing microalgae. Therefore, we grow microalgae during the different seasons to understand how our climate influences nutrient uptake. So far, we have experienced a winter experiment with snow up to our knees, a spring experiment where we nearly suffered heatstroke, and now finally a rainy autumn experiment is ongoing. The question still remains: Which season is most beneficial for microalgal nutrient recovery, and why?

– by Lina Mattsson

Lina Mattsson is a PhD student of supervisor Dr. Catherine Legrand in the Department of Biology and Environmental Sciences at Linnaeus University. She is a member of the research group Marine Phytoplankton Ecology and Applications and works on the Algoland project.

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Expedition Background

Academia - Industry - Citizen Collaboration - all in the name of Saving the Baltic Sea.
We have 2 projects to highlight:

THINKING GLOBALLY, ACTING LOCALLY: Here at the Biology and Environmental Science Department at LNU, we connect our work with local solutions for large-scale problems. Dr. Catherine Legrand, a marine ecologist with an eye for sustainability applications, and her team are finding new and exciting ways to use microalgae as a tool for cleaning carbon dioxide from the air and excess nutrients from water in a project known as ALGOLAND. (

CITIZEN SCIENCE: Norra Dragsviken is a small bay on the Baltic Coast of Sweden, close to the community on Skäggenäs. There, a close-knit community of longtime residents recall a time when life was good at Norra Dragsviken. Summer activities flourished in the beautiful bay, swimming and fishing and boating were enjoyed by all under the Swedish sun. Now, the murky waters and thick, smelly sediment keep both young and old at bay. With changes to the ecosystem due to human activities a clear cause, residents alarmed by the state of pollution and eutrophication in their once-beautiful seaside community, enlisted the help of local Linnaeus University researchers, to sample the bay, find out the status and see what they could do to save it. Linnaeus University, Kalmar County Administrative Board, Kalmar Municipality and the local water council together funded the investigation of Norra Dragsviken Two summers in a row (and counting!), researchers and undergraduate students from Linnaeus University’s summer course “Discovery of a Sustainable Baltic Sea” teamed up with locals from around Norra Dragsviken. An international group from Sweden, Great Britain, the Netherlands, China, USA, France, Spain, Canada and Pakistan set out in boats and completed an inventory of biological and chemical parameters. The exercise was an effort to compile data that sheds light on the ecological status of Norra Dragsviken, at the same time giving the students an opportunity to get hands-on practice and collaborate with residents to work locally on a problem that is global.

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