Red Sea Sponges research garners interest
Dr. Feras Lafi, a scientist in the KAUST Red Sea Laboratory of Integrative Systems Biology, has been investigating the unusual microbial communities in Red Sea sponges. This is the first time that there has been research access to these extraordinary sea creatures from the coast of Saudi Arabia, and the initial results suggest that the sponges are of significant interest to the biomedical community.
As part of the Global Collaborative Research (GCR) program, Dr. Lafi and his GCR partners recently published an article in the Nature publication, the International Society for Microbial Ecology Journal, regarding the sequencing of the microbial communities of several sponge species from the Red Sea. This builds on Dr. Lafi's Ph.D. thesis on poribacteria, a sponge specific phylum, at the University of Queensland in northeastern Australia.
Additionally, faculty members in the Red Sea Research Center have contributed their expertise to characterize the diversity and richness of local sponge communities. Dr. Lafi, Professor Christian Voolstra, Professor Michael Berumen, and Professor Timothy Ravasi began this process earlier this year by spending time surveying several coral reefs in the vicinity of the university and literally counting different sponges according to their species.
This information – the first systematic census of sponges in the Saudi Arabian Red Sea – will be compiled not only in order to understand this unique ecosystem and to motivate conservation efforts, but also to guide the team's future work with sponges. In particular, it will be important to ensure that species targeted for further biomedical applications are sufficiently common in the Red Sea to make the studies feasible.
Marine sponges are one of the oldest life forms on the planet, dating back approximately 600 million years. In some places they may occupy most of the available surfaces on the coral reef or the seabed.
These multicellular animals have a simple body plan and their tissues show little differentiation or coordination. Fixed in one place by a stalk or by settling in various underwater objects, sponges filter seawater through their pores, extract bacteria and use them as a food source, releasing the filtered water via the osculum.
The Red Sea, the warm and high saline body of water abutting the University campus, is a largely unexplored marine ecosystem. Its coral reefs, some 2000km in length, nourish over 200 recorded species of sponge, yet few of these have ever been studied. The sponges, their microbial communities and the surrounding seawater were all examined in Dr. Lafi's study using genetic sequencing techniques.
The sponge-microbe associations found in these sea sponges intrigue researchers because they cannot rely on their hard shell for protection, but rather on their chemical arsenal to survive attacks. Over millions of years of evolution, these sponges, delicate as they may appear, have developed a strong chemical defense system to protect themselves from predators.
It is the biotechnological potential of sponge-microbe associations that fuels the research that Dr. Lafi pursues and makes their focused investigation compelling for novel drug discovery.
With the support of the Coastal and Marine Resources Core Lab (CMRCL), the sponges were collected from four different habitats in the Red Sea together with samples of the seawater surrounding them. The KAUST team, together with GCR partners Dr. On On Lee (lead author of the paper) and fellow scientists from the Hong Kong University of Science and Technology led by Professor Pei-Yuan Qian, used pyrosequencing to "reveal highly diverse and species-specific microbial communities in sponges from the Red Sea".
Scientists cannot simply examine these marine microorganisms as only one per cent of environmental microbes can be cultured in laboratory conditions. To better understand these microorganisms, Dr. Timothy Ravasi, Associate Professor of Bioengineering, and his group at KAUST are using genomic and transcriptomic methods to examine the relationship between bacteria and sponges.
Pyrosequencing can characterize a sample quickly and accurately and is the method of choice to explore marine microbiomes. In addition to the four new phyla they identified using this method, Dr. Lafi and his team discovered that many of the bacteria within the sponges were absent from the surrounding seawater, although these microbial communities were consistent in the same sponges taken from different places.
There are two ways in which it is thought that sponges acquire bacteria. During the filter-feeding process described, sponges need to be able to recognize symbionts possibly using their innate immune system. Alternatively, parent sponges may transfer microbes to their progeny through reproduction; these same microbes have probably co-evolved over many generations and no longer have any presence in seawater.
It would seem that Red Sea sponges have highly sponge-specific or even sponge-species-specific microbial communities that persist despite their absence from the surrounding environment. Much work remains to be done to explore this diversity and its implications.
Collaborations with international higher education institutions such as this embody the University's goals to create partnerships among diverse fields. Dr. Lafi and the researchers involved in the sponge project anxiously await more exciting finds from these incredible animals found just off the shores of the campus.