Eilat

Achievements for each user project

Jan Pawlowski

Several plankton samples have been collected during the visit in Eilat. Following planktonic foraminiferal species has been identified and isolated: O. universa, G. siphonifera, G. ruber and G. sacculifer. Moreover, we isolated a certain number of acantharians, including Amphilonche elongate and the unidentified spherical species. In total, 12 samples of planktonic foraminiferans and 5 samples of acantharians were fixed in RNAlater for further study.

João Miguel Sousa da Silva

The results, although yet in their raw format, reveal the contrasting pattern between the metabolism of the meadows and that of the surrounding areas and highlight the importance of calcification in the community carbon balance.

Anders Meibom

During this project, we adapted the coral skeletal growth labeling technique previously developed in aquarium experiments for strontium 86Sr stable isotope to in situ conditions using scuba-diving: 4 Porites sp. coral nubbins grown on the IUI watertables by Pr. Aldo Shemesh (Weizmann Institute, Israel) were labeled in 4 successive pulses of 12h labeling separated by a few days recovery. Day labeling was carried out in parallel to night labeling in order to detect potential differences in skeletal growth rate and pattern between day and night in in situ, reef conditions (6m depth, natural irradiance). The labeled nubbins were then brought back to surface, and small tissue-covered fragments were subsampled and fixed for cellular structures analysis, while tissue-free skeleton are being shipped back to the Laboratoire de Mineralogie et de Cosmochimie du MNHN (Pr. Meibom), in Paris for NanoSIMS analysis of the Sr trace element incorporation into the newly accreted skeleton. Its spatial distribution in the coral skeletal microstructure will be analyzed by Pr. Stolarski and PhD student K.Janiszewska at the Paleobiology Institute, Warsaw, Poland. It is expected that new insights will be gained on the day/night biomineralization mechanisms in Porites corals, in the general context of coral chronobiology as discussed at IUI during this project with Pr. Oren Levy and students (Bar-Ilan University).
In addition a collaboration was initiated with Pr. M. Fine (Bar-Ilan University and IUI, Israel) to study the microstructure and pattern of Sr incorporation into the skeleton of corals grown at various seawater pH.

Joerg Wiedenmann

The short term objectives were fully achieved and a novel experimental system was established that allows us to simulate the internal light climate of corals - not only from deeper water but also from shallow water reefs and study the role of various different host pigments. This has wider implications for studies aiming to understand the adaptability of coral ecosystem to climate change.
Data generated during the ASSEMBLE visit are currently included in a manuscript.
Experiments and data analysis required to achieve the medium and long term objectives are still running and are expected to be completed within the next18 months.

Emma Ransome

This grant enabled an important study looking at the effects of temperature stress on quorum sensing and community interactions in bacteria associated with the scleractinian coral Stylophora pistillata. Quorum sensing is a form of bacterial communication known to modulate symbiosis, virulence, antibiotic production and biofilm formation in many bacteria. With research highlighting the integral role that specific bacterial communities may play in coral health, it is important to establish whether these communication systems are present in coral-associated bacterial communities and whether these systems are affected by environmental perturbations.

During the four week field study a number of corals were tested for bacterial signaling, some of which gave positive results. Further, a conserved signaling profile was found in wild and aquarium kept Stylophora pistillata fragments. This allowed a temperature stress experiment to be undertaken looking at bacterial diversity, abundance and signaling in S. pistillata while subjected to temperature stress. Further, methods for normalizing coral fragments and parameters for assessing zooxanthellae and host stress, learnt while in Eilat, were applied to this experiment.

This grant has allowed the successful completion of the first known study looking at the effect of temperature stress on coral-associated bacterial communication systems. Preliminary analysis shows the disruption of the conserved bacterial signaling profiles in S. pistillata with temperature stress. These preliminary results are extremely interesting, as they hint at the disruption of the normal functioning of coral-associated bacterial communities, which may help to begin to explain the onset of disease in many corals in times of temperature stress. However, these results are preliminary. A more comprehensive analysis is underway.

David Bailey

We obtained an excellent dataset, and are working with one of the scientists we met at IUI on writing up the first paper. We plan to submit it to Coral Reefs. A second paper will be written over the winter.

The first paper describes the biodiversity detected by baited cameras, compared to diver surveys. The second paper will be on the use of these two methods for the estimation of fish abundance. Both will make major contributions to the subject area.

As a result of the experience and contacts made at IUI we have subsequently been successful in obtaining British Council funding (BIRAX), to develop our collaboration further.

Ulf Jondelius

The purpose of my stay was to collect Acoela from sandy sediments in litoral and sublitoral habitats. Acoela are microscopic worms that are abundant in marine habitats, e.g. sandy sediments, corals, and mud. Acoela were previously classified within Platyhelminthes, but molecular phylogenetics strongly supports their position as the oldest extant group within Bilateria. In spite of their pivotal position in metazoan phylogeny, acoels are poorly known. Most of the 380 described species are from Northern Europe and the North West Atlantic. The Red Sea acoel fauna is largely unknown. My aim was to collect specimens of Acoela for taxonomic and phylogenetic studies. The material will be used to frame a phylogenetic hypothesis for Acoela based on ribosomal and mitochondrial gene sequences and morphology and to document Acoela as a component of cryptic marine biodiversity.
During my stay I was provided with sediment samples from staff and students at the IUI, which meant that I could spend almost all my time at the microscope sorting samples and identifying worms. I studied 22 samples of about 1 litre of sediment taken from 1 to 25 m depth.
Meiofauna was extracted from the samples after magnesium chloride anaesthetization and collected in sieves. All the microscopic worms were then collected individually with a pasteur pipette and studied under a compound microscope for identification and photography. Drawings of the specimens were also prepared. A total of 74 specimens belonging to 19 tentative species were collected.