Summary of Abstract Submission

Abstract Submission No. IO50-09-0036PresentationPoster


Anna Roik*1, Till Röthig1, Cornelia Roder1, Maren Ziegler1, Stephan Kremb1, Christian Voolstra1

1 King Abdullah University of Science and Technology, Saudi Arabia


The Red Sea accommodates one of the world's largest coral reef systems, yet exhibits distinct environmental regimes in comparison to other (sub-)tropical seas. Red Sea coral reefs are sparsely studied and surveys typically target communities of coastal macro-organisms, such as reef-building coral or fish assemblages, but continuous data on basic physico-chemical and biological factors are missing. To fill this gap, we monitored three reefs along a cross-shelf gradient in the central Red Sea during a full year, collecting data on currents, temperature, salinity, dissolved oxygen, turbidity, chlorophyll, inorganic nutrients, sedimentation, benthic algae settlement, and associated bacteria in biofilms and in reef water. Our data revealed a structuring according to seasons and sites for all measured parameters. For temperature and salinity the most conspicuous pattern was the seasonal fluctuation. In contrast, dissolved oxygen, turbidity, and chlorophyll showed most pronounced differences between sites. Further, multidimensional scaling using all physico-chemical parameters demonstrated remarkable discrepancies in habitat characteristics between the distant offshore and the midshore and nearshore reefs. Benthic algae and associated bacterial communities also displayed a spatio-seasonal structuring. Interestingly, algal communities changed stronger with reef site across the shelf, whereas differences in bacterial communities were more distinct between seasons. Our study provides baseline data to support research in the region, thus contributes to the understanding of Red Sea coral reef dynamics.