Arctic ecosystem engineers

The hollow rhodoliths that occur in the waters around Svalbard. This image shows rhodoliths on the sea floor off the north coast of the group of islands at a depth of 42 metres. (Image: Geomar)
The hollow rhodoliths that occur in the waters around Svalbard. This image shows rhodoliths on the sea floor off the north coast of the group of islands at a depth of 42 metres. (Image: Geomar)
November 24, 2014

FAU researcher proves algae species creates ecological niches

We all know how important coral reefs are for the ecosystem. In places where coral reefs occur, their three-dimensional structures provide ecological niches that have a positive effect on biodiversity. It is less well known that other organisms also create structures which serve as habitats. An FAU researcher has recently shown that the red coralline algae which live in the Arctic form niches for many species due to their unique shape.

Dr. Sebastian Teichert from the Chair of Palaeoenvironmental Studies studied red coralline algae found in Arctic waters around the islands of Svalbard located halfway between Norway and the North Pole. The algae here live on the relatively uniform, rock-strewn sea floor. They form a crust of calcium carbonate around the rocks on the seabed. These crusts grow very slowly but become thicker and thicker over the years, finally turning into round structures called rhodoliths. They enrich the ecosystem, as the algae’s tissue is a food source for other organisms, and are often hollowed out by boring mussels which chisel their way into the crust with their shells. This creates cavities which are used as shelters by other organisms, such as a variety of species of mollusc and fish.

The study, which used computed tomography scans and underwater photographs, confirms that these rhodoliths increase biodiversity in their environment. This is because the normal wide rock-strewn areas offer little protection. New ecological niches are only created when the hollow rhodoliths have formed, allowing a greater number of different organisms to exist alongside one another. ‘Hollow rhodoliths occur all over the world and also existed in geological history. However, up until now, there have been very few studies on their role in global ecosystems,’ says Dr. Sebastian Teichert. ‘We want to address this in future studies.’

Teichert, S. (2014) Hollow rhodoliths increase Svalbard‘s shelf biodiversity. Scientific Reports 4: 6972, doi:10.1038/srep06972

Further information:

Dr. Sebastian Teichert
Phone: +49 9131 8524782