Researchers create map to show human impact on marine life in Baltic Sea

PlanWise4Blue (PW4B) is a map application developed by researchers at the Estonian Marine Institute that allows anyone to examine the impact of human activities on marine life. The app can predict the individual and combined impacts of wind farm development, nutrient loading, and invasive species in the vulnerable reef and sandbank habitats in the Baltic Sea's northeastern region.

"If we study the impact of human activities on marine ecosystems without taking into account the specific species that inhabit them, we will overlook serious harms," Annaleena Vaher, a researcher at the University of Tartu, said.

Conservationists should consider how seaweeds and mussels, for example, contribute to reef habitat. "Some human activities may have a far greater impact on specific species that constitute the habitat than on the habitat as a whole."

Vaher and colleagues developed PlanWise4Blue application that predicts cumulative effects of 21 distinct human activities on 27 nature assets, to help aqua-culturists, wind farm developers and fishermen, among others, in planning their marine activities effectively and responsibly.

In a recent preliminary study, the app was used to evaluate the individual and combined effects of three types of human activity on reef and sandbank habitats in the northeastern Baltic Sea.

"We focused on three distinct anthropogenic pressures in Estonian waters: wind farm development, nutrient loading, and invasive species, such as the estuarine mud crab and the round goby," Vaher explained.

The researchers chose these three types of activities because control over them varies.

Even though the choice to construct a wind farm has already been made, its location can be adjusted by a few hundred meters if necessary. "Controlling invasive species, however, that have arrived in the Baltic Sea is very difficult, unless they are served in restaurants," she said. And the amount of nutrients that enter the sea is entirely dependent on human agricultural activity.

Fieldwork. Source: Estonian Marine Institute

"Of the three impacts evaluated, the current abundance of nutrients in water is the most detrimental factor to natural values," Vaher said.

This is an issue for all nine countries surrounding the Baltic Sea, not only Estonia, i.e., nutrients loading into the Baltic Sea from all nine countries.

If the inflow is not reduced, valuable seabed habitats will disappear and the water will begin to bloom. "Large algae and higher plants are in danger, especially marine eelgrass. This species is rather vulnerable to pollution; it requires plenty of light and clean water," Vaher said.

The destructive effects of nutrition can, however, be easily managed by people.

In their application, Vaher and coworkers modeled a future in which all nine countries surrounding the Baltic Sea limit the amount of nutrients entering the sea by one-fourth. "The outcome greatly improved the picture," Vaher said.

Although the Baltic Marine Environment Protection Commission (Helsinki Commission - HELCOM), which manages the Baltic Sea, has also emphasized the need to reduce fertilizer inflows by a quarter, Estonia, for example, has not yet lowered its own contribution to this level.

In addition, Vaher continued, it is unlikely that the major industrialized nations can accomplish such a reduction at this time: "National boundaries are less distinct at sea. HELCOM must coordinate the process so that all states reduce their nutrition inputs to the minimum."

Non-native, invasive species ranked second among the factors investigated in terms of harmful impact.

The round goby. Source: Estonian Marine Institute

"For instance, nutrients might cause an 80 percent decline in eelgrass habitat in some areas, but invasive species could cause a 30 percent reduction," Vaher explained. Controlling invasive species in the sea is nearly impossible and both species -- the estuarine mud crab and the round goby -- are now widespread and well-established in Estonian waterways.

"The impact of wind farms on marine wildlife is rather minimal." Only a small part of the wind turbine goes into the water and this new substrate (attachment surface, -ed.) can actually boost the number of marine mollusks, Vaher said. "The results showed that installing a wind turbine in regions where reef habitat does not occur naturally might generate a favorable foundation for reef species to adhere to."

"Our modelling showed that removing nutrients from the marine environment is necessary if we wish to improve the condition of the sea. Again, invasive species should be fished out and consumed wherever possible, and wind farms should be placed with extreme care to minimize impact on marine habitats."

All Baltic Sea countries could use the PlanWise4Blue model collaboratively, she said. "After all, we share a common sea, and decisions should be made collaboratively and scientifically."

The application might be valuable for marine planners, who could see on a map where it is most environmentally sustainable to plan a certain activity and what activities could be developed in the area to lessen the cumulative environmental impact.

The PlanWise4Blue algorithm uses current scientific literature and databases and translates this information into a format that enables the simulation of many scenarios.

The application's strength lies in its integration of all available scientific knowledge and the most up-to-date marine maps. Source: Kotta et al.

These maps could be used to evaluate the impact of various human activities on the ecosystem of the Baltic Sea.

The application's output maps depict the degree to which habitat area is diminished or expanded under this or that scenario.

One square on PlanWise4Blue maps represents a square kilometer. It is not technically difficult, Vaher said, to increase the application's resolution, but significantly more environmental data must be acquired first. "We are keep improving the application in light of new human stressors and scientific literature."

The app is a good illustration of how cutting-edge science may be applied quickly to address society's most pressing environmental concerns. "In this way we can make more informed decisions as a group," Vaher said.

The tool, which was commissioned by the ministries of finance and environment and is supported by several other organizations, is currently being tested with data from Estonia, Latvia and Finland.

"Estonia's strength," the researcher said, "is that we are small enough to test systems of this type; if they work, others will follow this lead."


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Editor: Kristina Kersa

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