Fantastic maerl and where to find it- a comprehensive assessment of the occurrence and importance of Sweden´s hidden marine biogenic reefs

The occurrence and importance of maerl beds, benthic marine habitats consisting of calcareous red algae, is a major knowledge gap in Swedish waters.

In other parts of the world these beds support high biodiversity and provide carbon capture and nursery grounds, hence offering several ecosystem services.

However, due to their susceptibility to anthropogenic stress and slow growth rates, they are under threat and in rapid decline.

This project aims to establish the distribution, importance and vulnerability of these biogenic reefs in Swedish waters.

Historical and present-day observations provided through field surveys, GIS prediction modeling and citizen science engagement aim to take stock of the extent and importance of maerl in Sweden using sparse historical records as a starting point.

An inventory of the flora and fauna of these long-lived habitats will be made based on sampling whole organisms and their eDNA, to highlight the role of maerl for marine biodiversity and seascape connectivity.

To establish the role of maerl from a climate perspective, laboratory experiments will measure carbon storage and carbonate production in both present and future scenarios.

This project will comprehensively collect, assess and deliver information vital for the future understanding of this marine habitat and its role in the economics and ecology of Swedish coasts.

Our results will provide the essential baseline knowledge of maerl needed for national and international management plans.