Assaf Vardi

I was born in Haifa, Israel, where I developed a passion to the sea and its mysteries.

Very early in my scientific career I was intrigued by microbial chemical ecology and with the ability of marine microorganisms to shape the biogeochemical cycles of our planet. I’m specifically interested in the chemical “language” used by marine microorganisms and the cellular strategies employed during acclimation to environmental stress conditions.

I earned a B.Sc in Biology from the Hebrew University of Jerusalem (1994), from which I also received my PhD in Molecular Ecology (2004). After conducting postdoctoral research at the École Normale Supérieure in Paris and at Rutgers University, I joined the Plant Sciences department at The Weizmann Institute in 2010.

I’m married to the artist Nivi Alroy, who reinterprets biological themes such as cell-cell communication and apoptosis, and projects them onto urban environments and architectural landscapes. We recently collaborated on a children’s book that explains ecological and environmental issues through the lives of microorganisms in the oceans. Nivi and I are parents to Michael.


Daniella Schatz

For as long as I can remember, I’ve been fascinated by biology, so studying life sciences in university was the obvious path for me to take. During my B.Sc studies, I joined Prof. Aaron Kaplan’s lab at the Hebrew University of Jerusalem, where I first met the world of aquatic microbiology. In 2005 I completed my PhD studies at the Hebrew University of Jerusalem under the supervision of Professor Aaron Kaplan and Dr. Assaf Sukenik of IOLR.  During my studies I investigated the biological role of toxin production in the cyanobacterium Microcystis from Lake Kinneret, Israel.  My collaboration with Assaf Vardi in these early years led to exciting new insights into the chemical signaling pathways that determine the phytoplankton composition in Lake Kinneret.  Among other things, we proposed a role for the toxin, microcystin, as a sensor for the degree of cell death within the population.

Following my PhD studies, I explored the novel phenomenon of biofilm formation in the cyanobacterium Synechococcus as a post-doc fellow at Bar-Ilan University, in Rakefet Schwarz’s lab.

I later moved to work in TransAlgae Israel, LTD. A biotech startup that aims to use transgenically modified algae for the biofuel, food and feed markets.

Currently, I am a Staff Scientist in Assaf’s lab. With the help of other group members, I created genetically modified diatoms that enable us to further understand the chemical languages that lead to the phenomenal success of these species in modern oceans. In addition, I am developing transformation systems for the coccolithophore Emiliania huxleyi; investigating host-virus interactions using a myriad of fluorescent and electron microscopic techniques as well as aiding the students in the lab perform their individual research.

Besides science, I enjoy spending time in the jewelry studio where I design and make silver and gold jewelry.


Shilo Rosenwasser

During the first years of studying plant sciences at the Faculty of Agriculture, Hebrew University of Jerusalem, I discovered a great interest is in cellular molecular mechanisms of stress responses. Instead of my original plan to be a farmer, I continued my education in the Hebrew University of Jerusalem, conducting PhD studies under the supervision of Dr Haya Friedman and Professor Joseph Riov. During this period we investigated the involvement of ROS and redox changes in the activation of senescence process in Arabidopsis plants. Using protein-based redox probes and bioinformatics tools we described early and pre-symptomatic changes in the mitochondrial redox environment during senescence processes.

Currently, I am a postdoc in Assaf’s group, investigating the molecular responses of phytoplankton to environmental stress conditions.

Using RNA-seq data we are investigating the transcriptome of Emiliania huxleyi cells during infection with its specific virus, monitoring the virus and host related transcripts over the course of infection, in order to indentify genes involves in host PCD response and virus replication.

In addition, using redox proteomics approaches and protein-based redox probes, we are studying the role of oxidative stress and redox regulation in activation of resistance versus PCD responses in the model diatom Phaeodactylum tricornutum.


Miguel Frada

Drifting like a plankton cell…I was born and performed all my early studies in Portugal. Later on, I drift to France and did my PhD at the “station biologique” from Roscoff (Universitee Pierre et Marie Curie), under the supervision of Dr. Colomban de Vargas. During three and a half years, I studied several aspects related to the diversity, ecology and physiology of the haplo-diploid life cycles of calcified haptophyte microalgae (coccolithophores). One of the most relevant studies described that the haploid phase of the major coccolithophore species in contemporary oceans, Emiliania huxleyi, is resistant to viruses (EhV) that infect and kill diploid cells. We proposed therefore that life cycle transition is used as a key strategy to escape viral attack. Soon after my PhD, I drift to New Jersey (USA). For two years I worked as a posdoc in the lab of Prof. Paul Falkowski at Rutgers University on lipid metabolism of diatoms. I focused on the impact of nitrogen source availability and quality on the photosynthetic quantum yield of lipid biosynthesis and genetic regulation of the central metabolism. I used as model the marine diatom Phaeodactylum tricornutum. In my new drifting zone, Israel, I will be studying in Assaf Vardi’s lab, in collaboration with Matt Johnson’s lab at Woods Hole Oceanographic Institute (USA), functional mechanisms of cell signaling and cell defense during trophic interactions between marine unicellular grazers and microalgal preys.


Orr Shapiro

I am a postdoc in Assaf’s group. My PhD from Ben Gurion University of the Negev in Beer Sheva focused on the microbial ecology of industrial wastewater treatment and was supervised by Professor Asher Brenner and Dr. Ariel Kushmaro. During my research I applied molecular and classic microbiological tools to analyze changes in a bioreactor’s community composition over time and how they relate to changes in process operation and performance. Parts of my work were dedicated to the effects of viral predation on the microbial community and to population dynamics at the microdiversity level, indicating the microbial communities found in such processes, and possibly other environments, to be much more dynamic and possibly more diverse then assumed previously and to be strongly influenced by phage predation. Other projects I worked on during my PhD included the development of miniature membrane bioreactor systems, improved universality of PCR primers for community surveys and the ecology of multicellular photo-magnetotactic bacteria.

My current goal is to develop a microfluidic-based model system to study coral microbiology and ecology in order to improve our understanding of processes leading to worldwide loss of coral reefs due to coral disease and mass bleaching events. The project is carried out in collaboration with groups from MIT in the US and the University of Sydney, AU.


Carmit Ziv

Being a farmer’s daughter that was highly involved in the farm’s work, it was only natural for me to focus my high education studies in agroecology and plant health. I completed my masters and PhD studies in the Hebrew University, in the Department of Plant Pathology and Microbiology. My main scientific interest at that time was to understand the molecular mechanisms governing environmental sensing and response to different environmental conditions of phytopathogenic microorganisms. During the course of my studies I acquired significant knowledge and experience in bacterial and fungal genetics and physiology, with emphasis on signal transduction pathways that control morphogenesis in response to environmental cues, like nutrient availability and stress conditions.

Currently I’m continuing my microbiological studies, though shifting from soil microbiology to the fascinating interactions between the marine micro-algae Emiliania huxleyi and its specific virus. I’m using highly advanced biochemical, genomics and lipodomic tools to uncover the involvement of sphingolipids in the viral infection of the algae and to understand the molecular mechanism of resistance found in some of the algal strains in the ocean. These special lipids are known to have structural and signaling roles in both the phytoplankton and the virus. As much as I get to know these intriguing bioactive lipids I learn to appreciate their amazing and important role in cell biology.


Uria  Alcolombri

I completed my Masters studies in the Weizmann Institute of Science under the supervision of Professor Dan S.Tawfik where I studied directed evolution of enzymes using protein engineering methods.  I started my PhD studies in 2011 as a joint student in the labs of Assaf Vardi and Dan Tawfik. My main research topic is Di-methyl-sulfonio-propionate (DMSP) and DMS production in unicellular marine algae. DMS and DMSP are crucial players in the global sulfur cycle and influence cloud formation and global climate. I am working towards identifying the molecular mechanism and key enzymes involved in this important anabolic process of DMS production.

When not in the lab, I enjoy taking long walks in the open fields with my lovely dog, Juli.


Uri Sheyn

My love of the sea and surfing led me to choose a B.Sc track in Marine Environmental Studies at the Israeli Maritime Collage in Michmort. The marine environment and earth’s climate have always been a source of great interest to me.
After traveling the world, at the age of 35, I knew science is what I enjoy doing most, and combining it with my love to the sea gives me a great pleasure.
My Ph.D studies follow those of my M. Sc, in which I  study ways to identify stress and viral infection in an ecologically important alga, Emiliania huxleyi. This species is a coccolithophore that forms massive bloom and has a huge influence on the world’s ecology and climate. I try to do so using different molecular tools to investigate the cellular properties of viral infection on both the single cell and population levels, hoping to take these insights to the broader scope of global climatic and biogeochemical processes.


Shiri Graff

I completed my B. Sc studies in molecular biochemistry, in the Technion.

I completed my M.Sc studies in Assaf’s lab and am currently a Ph. D student. In the framework of the lab research I am challenging the diatom Pheodactilum tricornutum with different stress conditions and checking their oxidation state using microscopy and FACS methods.

My great love is the ocean, and I spend as much time as possible sailing in the Mediterranean and any other possible body of water.


Guy Schleyer

Born and raised in Jerusalem, the sea has always been a bit out of reach, let alone the ocean. Even so, growing up watching “The Wonderful Adventures of Nils Holgersson” made me concerned for the environment and the oceans and the impact we human beings had on them. I completed my BSc studies in chemistry and biology at the Hebrew University of Jerusalem. I chose this program as I was not able to decide what I liked more – molecules or the organisms that produced them. Later in my MSc studies in chemistry at ETH Zürich, I found a way to combine both worlds – my thesis under the supervision of Prof. Jörn Piel from the Institute of Microbiology allowed me to delve into the fascinating world of secondary metabolites (AKA natural products), focusing on Ribosomally Synthesized and Post-translationally Modified Polypeptide (RiPPs) produced by symbiotic cyanobacteria and the interesting chemistry they present. Back to those early childhood experiences, it still amazes me how a book from 1906 (on which the TV series was based on) managed to be so accurate in portraying and warning us against the environmental issues that we face today. Starting a PhD at the Vardi lab, I believe, will allow me to pursue chemistry in the important context of ecology and the pending problems associated with the marine environment. During my PhD I hope to address several questions concerning the secondary metabolites involved in the interactions between the coccolithophore Emiliania huxleyi and its surrounding. And to finish with a quote by Douglas Adams: “The system of life on this planet is so astoundingly complex that it was a long time before man even realized that it was a system at all and that it wasn’t something that was just there”.


Adva Shemi

“How inappropriate to call this Planet Earth, when clearly it is an Ocean” (Arthur C. Clarke).

What brings me to research in general and specifically to study marine biology is the opportunity to be creative, to develop a unique and open-minded way of thinking about nature.

I completed my B.Sc in Marine Environmental Studies at the Israeli Maritime Collage in Michmort, where I lived by the sea, diving into a mysterious and intriguing world of marine organisms, geobiochemical cycles, climatology, evolution, and more.

In my M.Sc research I am studying the cellular process of autophagy in the context of algal-blooms dynamics.  I am working on the unicellular algae E. huxleyi, the pet organism in our lab for studying host-viral dynamics in the marine microbial world.


Assaf Gavish

I am an M.Sc. student in Assaf’s lab, working on in vivo visualization of disease development in the coral Pocillopora damicornis by fluorescent strains of its bacterial pathogen Vibrio coralliilyticus.

I received my B.Sc. in Biology from the Tel Aviv University. There I helped design and develop a continuous quantitative pathogenicity tracking system in Amir Sharon’s group, and worked with Professor Amotz Zahavi on a theoretical project about the evolution of Nitric Oxide as a neurotransmitter.

I find biological interactions such as disease processes fascinating, and I enjoy the challenge of developing new tools for research.


Noa Barak

Since I started to be interested in science I was intrigued by host-pathogen interactions. To find a research group that combines this subject together with marine biology made it irresistible for me. I am an MSc student in the lab where I study algal-bacterial interactions during coccolithophore blooms.

Before joining Weizmann I completed my BSc in Life Sciences at Tel-Aviv University.

Besides science I have a great passion for dancing and movement.


Adi Volpert

“So I started to walk into the water. I won’t lie to you, boys, I was terrified! But I pressed on – and as I made my way past the breakers, a strange calm came over me. I don’t know if it was divine intervention or the kinship of all living things, but I tell you, Jerry, at that moment – I was a Marine Biologist! ” (George Costanza, from the 78th episode of Seinfeld)

For 99% of the people, when you tell you are a “marine biologist”, the only thing comes up in their mind is the famous monologue above, but for me it’s the actual life, and a big privilege to do so.

I completed my B.Sc in the School of Marine science in Michmoret and now I’m an M.Sc student in Assaf’s lab, working on Redox signaling and cell fate regulation in a bloom forming diatoms.

I believe our future lies within the oceans, in my study I hope I can help with another small step to benefit it.


Former Students

Shlomit Sharoni,



Amit Davidi,

Limor Agi,

Yossi Cohen,

Revital Hashayev,


Visiting Scientists

Prof. Gordon Wolfe, UCS Chico.

Dr. Esti Winter, TAU, ProReef.

Michaela Mauss, Friedrich-Schiller-Universität, Jena.

Ronit Abramson, Yale University.