Charistmatic KAUST Beach Animals!

Several weeks ago, KAUST workers finished construction of our wonderful new beach. While there are many features that are not yet available, a swimming area has been roped off for exploration. I have visited the beach three times now, and have been delighted to finally explore an intertidal Red Sea ecosystem at my leisure (i.e. all day). Yet many snorkelers have been unhappy with the turbidity (“dirty-ness,” lack of clarity), claiming that snorkeling yields no sights. The turbidity issue is due to the fact that a lot of new sediment has been added to the area (our beach is actually imported – I disapprove, but moving on) and the swimming area is between two long spits of land that have been extended for the purpose of construction, flanking the swimming area with even more sand… Yet there is much to see at the KAUST beach as long as you slow down, cover a lot of area, and swim down to the bottom (only 2-3 meters) when snorkeling to get a closer look. The following photos (with cool informative captions) were all taken from within the swimming area of the KAUST beach, most below 1 meter depth. I invite you all to see the intertidal ecosystem you now have access to, but may have passed over; diver, snorkeler or just beachcomber, there is much to see!

Our first photo is of a pair of nudibranchs, Plakobranchus ocellatus, probably the first animal I saw at the KAUST beach. Found in even only centimeters of water, they eat macroalgae and actually save the chloroplasts within their own tissue to benefit from their ongoing photosynthesis!

A more detailed photo of the same species:

OK, so I cheated on the next photo - it was taken in a glass dish on the beach. But I found the slug pictured, Hypselodoris infucata, in a few centimeters of water on the beach, so you could too! It eats sponges, and is awesomely colored - a typical trait of numerous nudibranchs.

Just some coral with a runner of macroalgae growing above it; perhaps 50 cm deep...

Giant clam (Tridacna sp.) with macroalgae nearby. Giant clams rock because they use the same algal symbionts corals do in their mantle tissues to photosynthesize and grow!

A cool blue sponge (phylum porifera). These filter the seawater for food - I read recently that some species of sponges have been found to remove even viral particles from seawater as food - very efficient animal filters!

What is this? Some macroalgae?

No! It's a cowrie! A type of snail, kinda. The fleshy brown branchy stuff in the previous picture is actually part of their mantle tissue, which they raise up over their shell for camouflage. Spook them, and they retract into their shell, revealing its bright pattern.

No, it's not an eel. My Irish friend Damien holds an easily caught pipefish, an animal related to seahorses and very easy to approach underwater.

Now this is an eel. I can't believe I found one here! Again, it's perhaps half a meter deep - and this lil guy is only about as thick as one of my fingers - but that didn't keep him from threatening with an open mouth display of tiny (developing!) teeth!

A cool hermit crab has stolen some unfortunate snail's shell...

One of my favourite pics from today, this is an upside-down jellyfish (Cassiopeia xamachana), distributed tropically world-wide. It uses algal symbionts in some of its tentacles to photosynthesize like a coral! And if one symbiosis wasn't enough, you might be able to see tiny larval crustaceans (shrimp?) swimming above the tentacles - I have video and will upload it sometime. Ask me if you're curious.

So I cheated a bit on this photo - I adjusted the color levels so you could see it. Still, a cool upload. Came across this little puffer in a half meter of water; it got spooked and swam away. Puffers are known for their production of tetrodotoxin, which affects the central nervous system. So, don't eat them - unless you are in Japan where they will prepare you a special portion based on your weight, age and sex that won't kill you but will bring you to the edge (fugu).

Finally, a shot from maybe 1.5 meters depth. Looking to the surface over a coral head, you can see lots of juvenile snappers (Lutjanus ehrenbergi) hunting here in the shallows for benthic invertebrate food - much safer than the dangerous reef until they grow larger. Beautiful!


For any KAUSTers, I go to the beach most weekends, and would love to share more with you. Life is everywhere in the sea!