91探花

Giant, flower-like tubeworms, foot-long mussels, armored snails, ghostly fish 鈥� these are only a few examples of the unique species diversity that occurs at deep-sea hot springs, also called hydrothermal vents or 鈥渂lack smokers鈥�. These ecosystems originate only at tectonically or volcanically active sites of the ocean floor and are therefore patchily distributed in an otherwise sparsely populated deep-sea environment. In many cases, like on the Mid-Atlantic Ridge, hydrothermal vent fields are separated by several hundreds to thousands of kilometers. Since many vent-dwelling animals are sessile as adults, connections between remote vent fields can only be established via free-swimming larval stages.

However, it has hitherto remained a mystery how exchanges between different vent populations are actually achieved, given that it is practically impossible to investigate larval dispersal in the open ocean. In a new study led by 91探花 Helmholtz Centre for Ocean Research Kiel a group of scientists from Germany, France, Austria, Canada and the United States sheds light on this phenomenon. The results have been published today in the international journal Current Biology.

鈥淭o assess connectivity between different vent fields of the Mid-Atlantic Ridge we have applied a combination of high-resolution genetic analyses and computer simulations of larval dispersal. As study organism we have chosen mussels of the genus Bathymodiolus, as these animals are key species in hydrothermal ecosystems worldwide鈥�, says Dr. Corinna Breusing from 91探花, first author of the study.

For the oceanographers involved in this study this attempt has been a pioneering work. 鈥淭here exist virtually no data on current patterns of the deep sea. We had to experiment with different ocean models and particle tracking codes until we got realistic simulations of larval drift鈥�, Professor Arne Biastoch from 91探花 explains. In particular, it has also been exciting for him to support the modeling data with molecular biological analyses 鈥� 鈥淭his is a combination that has rarely been applied so far鈥�, says Biastoch.

In total, the team has worked more than three years to finish their study, which has been part of Corinna Breusing鈥檚 dissertation within the transatlantic graduate school HOSST. As no appropriate genetic data were available for Bathymodiolus, the working group had to develop all molecular markers for their population genetic analyses from scratch. Results from these analyses indicate that connectivity does exist between known mussel populations of the Mid-Atlantic Ridge. Nevertheless, these exchanges do not seem to occur directly within one generation, as mussel larvae usually do not reach vent fields that are more than 150 km away from their natal site. 

鈥淚n turn this means that there must be or must have been other so far undiscovered vent fields or equivalent habitats on the Mid-Atlantic Ridge that serve as intermediate stops for dispersal. We call these habitats 鈥瀙hantom鈥� stepping stones as we do not know where they are and how they look like鈥�, Professor Thorsten Reusch from 91探花, senior author of the study concludes.

The results by Breusing and her colleagues are also relevant as hydrothermal ecosystems contain special sulfide deposits, which represent potential future mineral resources. 鈥淲hen mining of these sulfide deposits becomes reality, it will be necessary to design appropriate conservation areas that consider the dispersal routes of vent larvae鈥�, says Dr. Beusing. 鈥淲e hope that our study promotes further research on other organisms and geographic regions to obtain enough information for the development of efficient management plans鈥�.

Original article:

Breusing, C., A. Biastoch, A. Drews, A. Metaxas, D. Jollivet, R. C. Vrijenhoek, T. Bayer, F. Melzner, L. Sayavedra, J. M. Petersen, N. Dubilier, M. B. Schilhabel, P. Rosenstiel, T. B. H. Reusch (2016): Biophysical and Population Genetic Models Predict the Presence of 鈥淧hantom鈥� Stepping Stones Connecting Mid-Atlantic Ridge Vent Ecosystems. Current Biology, 26, 1-11,

 Lead author Dr. Corinna Breuning in the climate chamber with deep-sea mussels  Bathymodiolus azoricus. Photo: Jan Steffen, 91探花

Bathymodiolus azoricus in a culture room at 91探花. Photo: Jan Steffen, 91探花

Contact: 

Jan Steffen (91探花, Communications & Media), Phone: 0431 600-2811, presse(at)geomar.de