Ronny Steinberg

Eco- and stress physiology of Vaucheria mats in the Wadden Sea – Implications to range expansion and ecosystem function

The rise of seawater temperature in the North Sea are continuing as a consequence of climate change. New species from warmer regions benefit from higher temperature and settle down in the Wadden Sea. Vaucheria sp. is one newcomer in the Wadden Sea, which were reported as recent invader to lower shores at the border between tidal and subtidal in the sedimentary Wadden Sea.

Vaucheria sp. forming extensive turfs at and below low tide level under fully marine conditions near the Island of Sylt. Dense turfs of green filaments rapidly expanded over an area of 180 ha within 3 years. The distribution of the Xanthophyceae Vaucheria sp. in the lower intertidal zone of the Wadden Sea has the potential to change the functioning of the ecosystem sustainable.

The aim of my PhD project is to investigate the effects of mass settlement on tidal flats. Also, the habitat requirements of Vaucheria sp. shall be determine, to characterize this new invasive alga and thus contribute to predictions of further spread.

Therefore, the habitat requirements and physiology of Vaucheria sp. be studied to characterize this invasive alga and to make predictions about its future spread. For this I will investigate the effects of different temperature and light conditions on growth, reproduction and photosynthesis of Vaucheria sp.. The results are to be compared with the conditions at the study site on Sylt. This should enable conclusions to be drawn about the future distribution. Furthermore, the interactions with the local fauna, the microbiome and the impact on the biogeochemical cycle in the lower intertidal zone of the Wadden Sea are investigated.

This project is in cooperation with the Alfred-Wegener-Institute on Sylt.