The KAUST motto is: "Through Inspiration, Discovery". So, it's my last day at KAUST, and I've certainly been inspired. The labs and facilities are well-equipped, the architecture is stunning. The Red Sea... well.... it speaks for itself.

Though you might think of Saudi Arabia as remote and isolated, KAUST has literally created a scientific oasis in the desert. We have all traveled here from various places (Australia, New Zealand, the UK, Hawaii, and Boston.... to name a few....), but our dispersal across the globe has been for good reason: to come explore the Red Sea and do some new and exciting science. Though I might be geographically isolated at the moment, I have been in good company. In fact, I have been surrounded by a team of stars: Dr. Michael Berumen (my collaborator and host), as well as Dr. Howard Choat (JCU), our previous blog posters, a team of KAUST masters and PhD students, and now Michelle Gaither and Dr. Joseph DiBattista, from the University of Hawaii.

In the last post, Kathryn talked about how fungid corals move surprisingly far. Lizzie talked about how she's going to find out how far fish move within the course of their lifetime. And now, Joey and Michelle are asking about fish movement over evolutionary time - how closely related are different populations of fishes, how does geography influence their populations, and how do unique species form? While we humans are remarkably mobile thanks to air travel, fish movement is a bit more of a mystery. Trying to re-trace history is a tricky task-- especially here in the Red Sea.

Dr. Joseph DiBattista is a postdoc in the Bowen Lab at the University of Hawaii, who is here with HIMB graduate student Michelle Gaither. Joey did his bachelors, masters, and PhD degrees at McGill University in Canada before moving to more tropical climes.


Sniff, sniff ... I love the smell of rotting guts in the morning. The sights and sounds are infectious as the Jeddah fish market gets into full swing. Vendors shouting, the floor slick with a layer of piscivorous slime, colors abound.

The inability to take pictures due to local customs will make identification of the more obscure fauna a bit difficult, but otherwise this place is a gold mine.

We've actually come down to the Red Sea as part of a large phylogeographic project in hopes of expansion. Indeed, over the past 5 years we have collected samples from reef fish and some invertebrate species at a number of sites in the Indo-Pacific; genetic methods have allowed us to assess the level of connectivity (and dispersal) between islands, archipelagos, and coastlines. Given that our home base is the Hawaii Institute of Marine Biology (not bad at all!!), the survey was initially focused on addressing some interesting historical questions quite close to home.

For example, Hawaii is known for the highest level of endemic (indigenous and exclusive) reef fish fauna in the world, and yet we still don't know where they came from or when they got there. The two competing hypotheses are that reef fish colonized from the west Pacific via an offshoot of the warm water Kuroshio current somewhere near the coast of Japan, or they otherwise made their way up the southern line island chain, perhaps using Johnston Atoll as a stepping stone for colonization into Hawaii. These ideas are based on the overlap of fish fauna between these regions, as well as some models that simulated larval trajectories between such sites. Sequencing DNA at mitochondrial genes (i.e., Cyt b, COI) have allowed us to address theses competing hypotheses by assigning approximate dates to population splitting or colonization events, although the verdict is still out.

The push to get into the Red Sea was spurred by the fact that this body of water is similarly renowned for a high degree of endemic fish fauna (~17% overall). That is, ~17% of the reef fish in the Red Sea are found only in the Red Sea. In fact, endemism is as high as 50% for some charsimatic taxa like the butterflyfishes.


Chaetodon semilarvatus (L) and C. larvatus (R) are both butterflyfish species found ONLY in the Red Sea (Photos: R. Rotjan)

What can explain such isolation? Well, several barriers to dispersal from the Red Sea region have been proposed. First, the narrow (18 km wide) and shallow (100 meters deep) nature of its only connection with the Indian Ocean, the Straight of Bab-el-Mandab, presumably restricts movement of planktonic larvae in and out. This is particularly true during low sea-level stands as recently as 10,000 years ago that decreased the exchange of water masses through this narrow straight and may have led to massive extinction of fish fauna.



Another potential barrier exists just outside of the Red Sea in the Gulf of Aden and Indian Ocean. Indeed, a lack of suitable reef habitat from Somalia to India or Kenya, due in part to the cold water upwelling found off most of this coastline, may greatly restrict the dispersal of reef fish larvae and thus act to reinforce endemic species. Genetic tools provide a means to test these ideas. So, it's now back to the lab to process all of these samples! Balancing the taxonomic books is not simple... but here in the Red Sea, hopefully we'll come out in the black.

Guest post from Kathryn Furby, also working at KAUST in Saudi Arabia:

As a coral biologist, I often feel defensive about my level of excitement for an animal that looks like a slimy rock. Corals build islands and protect coastlines from cyclones. Coral creates structures and habitats for fish and other invertebrates to live. There are many important facts circulating in the public and scientific communities about coral reefs, but there aren't enough exciting rumors.



The corals you are most familiar with are stationary, cemented to a network of reef that can extend for miles, like one giant life form. Most tropical reef corals undergo a pelagic larval phase. This means that after spawning, the corals' gametes combine in the water to form free-swimming larvae. This is the only phase of a coral's life where it is able to select its habitat, so you can imagine how important it is.



Once the coral has "settled" on a suitable hard substrate (free of algae and other competitors), it is literally stuck there for the rest of its life. This photo shows baby Stylophora corals that have settled on a larger recently dead Acropora coral.



Meet mushroom corals, family Fungiidae, genus Fungia. These little corals are not the branching Acropora or massive boulder-like Porites coral that you know (and love). Fungia are usually single polyps, and thus are individuals instead of colonies. Fungia mushroom corals consist of a circular disk with one mouth (usually) on the surface.

Exciting rumor #1: The fastest moving coral in the world is the mushroom coral.



This coral has the same free-swimming phase as other corals and also attaches to a suitable hard substrate of its choosing. In this photograph you can see at least three young Fungia corals that are attached. You can see that from the side, young mushroom corals look like their namesake, mushrooms. However, once it reaches a certain size, mushroom corals detach from the reef.

At this point, all bets are off. No longer imprisoned by a base cemented to rock, Fungia corals can continue to move during their youth. Like a student's choice to move away from home for college, maybe backpack through Europe, the mushroom coral continues to move until it reaches a certain size.

How can a coral move?



Figure 1 from Chadwick-Furman and Loya 1992, reproduced with permission from author.

Mushroom corals can be moved passively and move actively. Being a small aerodynamic disk in an ocean environment is tough. You're at the mercy of currents and extreme storms far more than your average sedentary coral. Small mushroom corals often get picked up by current and wave action and moved. Statistically speaking, it's extremely likely that the coral gets dropped upside down. When I first started studying these corals, I got to this point in my research and was boggled by how these animals had survived natural selection. If the coral landed mouth down, it would eventually bleach and starve simultaneously. At the beginning of my fieldwork, I spent a lot of time flipping Fungia back over, saving the world one coral at a time. Or so I thought. As it turns out, Mother Nature is much more clever. Mushroom corals can swell the tissue around their skeleton and actively move. They can also use this mechanism to right themselves after being flipped over. The process is slow, it can take days to complete. If the coral is on sand, it can blow water through its mouth, making a small indentation around it. It is then able to slowly move up the side of the hole until it can flip back over.

Exciting rumor #2: Mushroom corals are also flipping corals.



Mushroom corals are the only corals that can move or be moved onto sand and live happily ever after. As they grow bigger and heavier, they tend to move vertically down the reef, mostly thanks to gravity. As a result many large mushroom corals will end up on the sandy bottom of a reef. When this coral dies, other big sedentary corals are able to colonize their skeletons as a perfect hard substrate.



This photograph shows two dead mushroom corals that are becoming part of the reef. By moving onto sand patches and becoming new reef substrate, mushroom corals are able to create and expand reefs.

In an era of rising sea surface temperatures and ocean acidification, coral reefs need all the help they can get. Fungia are just the super hero corals needed to help expand reef boundaries. They might just become the next charismatic mini-fauna to champion reef preservation. Next time you see a reef in the tropics or in an aquarium, flip out over corals!

-Kathryn

It is a great pleasure to introduce the first of a series of excellent guest bloggers who I have been working and diving with here at KAUST, in Saudi Arabia. While I am here examining the nutritional basis of corallivory, Lizzie is busily gearing up for an ambitious and important project that will examine the movement of adult reef fishes.


Dr. Lizzie Tyler is a postdoctoral researcher at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. She is studying the movement of coral reef fish in the Red Sea. She gained her doctoral degree from Oxford University in the UK, where she worked on marine reserves in Zanzibar, East Africa.

Have you ever thought: "what would I bring if stuck on a deserted, desert island?" Being extremely practical, my answer would be loads of freshwater and some form of shade. Or, in earlier years, I might have made a top-10 list of "must-have" books, or music, or something utterly useless on a desert island.

On my way here, I flew over Egypt, of course all-the-while wishing my friends and colleagues in Egypt a smooth and safe transition in this tumultuous time, following the recent chain of events. You'd never know from the air that anything had changed, though. I flew over Luxor (the ancient city of Thebes) at sunset, and then over the Nile, and then Valley of the Kings. Looking down at the desert with the setting sun was stunning (sorry no photos - couldn't get my camera fast enough), and I was struck at the beauty of desert mountain chains.

Hola! Things here in Bocas del Toro are going well. We have had many fish-related successes in the lab and the field. One of our more exploratory endeavors was to set out a light trap and do a plankton tow in the hopes of glimpsing some larval fish.