Where are you from, and what is your role in Extreme 2004?

I am an associate professor of marine biology and zoology at the University of Vienna, Austria. I have been invited to this cruise by Craig Cary to offer this Extreme 2004 program to all kids in Austria. In case you are studying German in school, check out the German web page with the daily logs (www.hydrothermalvent.com). Of course, I will be working also on my scientific projects funded by the Austrian Science Foundation for the study of the meiobenthic community — small animals in the size range up to 1 mm — at hydrothermal vents and by the Academy of Science in Austria for the study of the infection mode in tubeworms.

What questions are you trying to answer and why?

The first project aims at characterizing the meiofauna community of East Pacific Rise 9°50'N hydrothermal vents and the adjacent deep-sea sediments so that the species diversity, abundance, biomass, and distribution are documented according to well-characterized habitats within this ecosystem. This is the first time in vent research that animals in the size range between 50 to 1,000 micrometers will be studied. This information will allow us to distinguish communities within the spreading center between active and inactive sites, either living on basalt, sulfide chimneys, or mud. This data will allow us to characterize distinctive communities at vents and to develop hypotheses on the origin and evolution of vent meiobenthos.

The second project studies the acquisition of symbionts in the giant tubeworm Riftia pachyptila symbiosis. We know that each host generation has to acquire their symbionts de novo from their environment. We investigate how and when the tubeworms take up their symbionts. We distinguish three different phases in the life cycle of the tubeworms ('Triphasic life cycle'): a sessile symbiotic phase of juveniles and adult, a vagile non-symbiotic phase of larvae swimming in the water, and a sessile non-symbiotic phase larva. After the planktonic larva settles, it undergoes a dramatic metamorphosis. Shortly thereafter, the uptake of one specific bacterial phylotype, the respective symbiont, takes place. We believe that this uptake of symbionts is achieved via an infection through the skin of the worms and not as postulated earlier by uptake through the digestive tract. To investigate this infection process, we aim to collect very tiny animals. To do so, we deployed so called VASD (Vestimentiferan Artificial Settlement Devices) at a hydrothermal vent field called TICA during last years' cruises. After recovery of the VASDs, we will search for the 'babies' (and hopefully find many!) and fix the animals for various immunohistochemical methods and for in situ hybridization on the light and electron microscopy level.

Why is this research important? What are the benefits?

First Project: We know from many studies carried out over the past 15 years, that only a few marcrofauna species (large animals) are adapted to live in this extreme environment. The species number is low, but the abundance of these species is very high. However, the small meiobenthos has received so little attention during this time that we still do not know if these small animals follow the same trend. In order to understand an ecosystem, I believe it is important to consider the entire community. Also by discovering and describing new species, this work will contribute to our knowledge on the biodiversity that exists in the oceans.

Second Project: The tubeworms are entirely depend on their symbionts and yet they don't pass them on directly to their offspring? Why not?? For me this was always an intriguing question. The knowledge of the mechanism of transmission in this obligatory symbiosis will give us not only insight into the evolution of this deep-sea association but also in the evolution of symbiosis in general.

What's your background and what lured you into marine science/education?

As an Austrian having grown up in a land-locked country, the sea was far away for me. However, every summer my parents took me to the Northern Adriatic Sea on vacation. My fascination with the sea started when I first learned swimming in the sea and collected shells from the beach. Of course, this created a strong personal link to holidays for me at that time. Only much later, becoming a zoologist and marine biologist, did I learn that going to the sea meant work.

Initially, I was mostly interested in the evolution and phylogenetic relationships of lower marine worms, but later I became fascinated with symbiosis. Some worms living in the sands of coral reefs are completely covered with a fur of bacteria. These hosts carry their symbionts to sand layers, where chemicals are available for carbon fixation. In return, some of the bacteria serve as food for the host. Also close to the coral reefs, mangrove swamps harbor similar symbiosis -- for example a colonial ciliate. Like the worms, the ciliates also live on their bacteria.

After receiving my Ph.D. from the University of Vienna in 1992, I was fortunate to be invited on a cruise to the deep-sea hydrothermal vents of the East Pacific Rise. I became hooked on this remote marine environment when I went on my first dive in Alvin. I wanted to study the giant tubeworms. But how could I do that as an Austrian without having access to a research vessel and a submersible? So I decided to work on tropical shallow-water symbiosis for a few post-doc years in Germany and the U.S. before I found the courage and opportunity to move my research into the deep sea. Now more than 10 years after my first dive, I have been invited on 9 cruises to the hydrothermal vents and was able to take along 6 of my students on U.S. research vessels. Just recently, for the first time in Austrian history, I received funding to rent a submersible, but this will occur later, sometime during the next year.