Roscoff

Achievements for each user project

Kenyon Mobley

Due to the diligence of the support staff at Roscoff in collection of specimens, we sampled 55 Entelurus aequoreus, 15 Nerophis ophidion, 13 Syngnathus typhle, and 1 Syngnathus acus. All Entelurus aequoreus will be used for genetic analyses relating to the main goal of the project. Because of the location of Roscoff at the entrance of the English Channel and North Sea, this population should reveal whether significant gene flow connects populations originating from the southern (Biscayne Bay) and western (Irish Sea) Atlantic Ocean with populations from the north (Norwegian Sea, North Sea). Unfortunately we did not have enough live female specimens to measure egg size. Apart from that, this was a successful visit and the data collected will be invaluable to our study.

John Henry Bothwell

This proposal aimed to improve our understanding of coastal biodiversity in the brown seaweeds by comparing the distributions and early embryogenesis of cryptic Ectocarpoid species. The final project differed slightly from that submiited, as one applicant (Simon Rybak-Coare) was unable to come for personal reasons. Nonetheless, the trip was extremely productive, as follows:

I. Working with Akira Peters and Nathalie Simon for the first week, both based at the host institute, I learned how to identify and culture field-collected samples of the various species of cryptic Ectocarpoid seaweeds (Ectocarpus, Kuckuckia, Pylaiella etc.). As a new PI, working on brown seaweed development, I am now bringing this knowledge to my own University, where it should stand me in great stead for the rest of my career. I am extremely grateful to the Station Biologique and to ASSEMBLE for this training.
II. Working with Susana Coelho and Laurent Laguerre, I learned how to stain microtubules during algal embryogenesis and carried out preliminary experiments to look at microtubule distribution in Ectocarpoid seaweed embryos. This work with Dr. Coelho was so successful that, in the third week, we wrote a Royal Society-CNRS joint project grant application which we hope will provide further funding for both our labs.
III. Finally, working with Delphine Scornet, I performed a genomic DNA extraction on two strains of Ulva. This was an unexpected additional project, but one which taught me DNA extraction protocols which will help with future research on my main ASSEMBLE project.

Andrew Gillis

We were able to accomplish aims 1 and 2 (there was not a sufficient embryo supply to accomplish aim 3). A number of embryonic stages of S. canicula were injected with vital dyes, and several different drugs were delivered to developing dermal denticles via bead implantations. Dye injected and bead-implanted embryos were fixed at the SBR and shipped back to the University of Cambridge, where further analyses will be conducted over the coming months.

Bruno Jesus

Roscoff Aber bay sediments develop phototrophic (bacteriochlorophyll a-containing) eye- visible pink microbial mats where purple bacteria dominate (Chromatiaceae). The goal of this project was to investigate the microbial diversity of these mats, to estimate their biomass by remote sensing and evaluate their contribution to carbon (CO2) fixation.

The mats were sampled at low tide during 25,26 and 27 of August. Spectral reflectance, photosynthesis/respiration and sediment collection were carried out. Three sediment areas with different bacterial concentrations were selected, i.e. low, medium and high biomass. Surface scrapes were taken to carry out a molecular analysis of the microbial populations and to measure sediment cohesion.

All measurements were successfully carried out and data processing is currently undergoing. The main preliminary results were: O2 flux measurements showed that the microbial mat seems to be respire more than photosynthesize; spectral reflectance showed a BChla signature with absorption maxima at 792 and 850 nm; high bacterial biomass sediments showed higher cohesion suggesting that these biofilms may play an important role on sediment erosion.

The second week was dedicated to examining the diversity of the anaerobic anoxygenic bacteria from these biofilms. DNA and RNA were extracted from the sediment and 16 rRNA and pufM genes were targeted for PCR amplification, cloning and sequencing. We are currently waiting for the sequencing results.

Once all data are processed we will be able to provide a comprehensive analysis on the role of these biofilms. We will also be able to develop a reflectance index to detect BChla-containing bacteria in intertidal sediments.