Location, Location, Location!

How great is Washington State?! Srsly. Pretty, pretty great.

This was originally posted by Mother Nature Network.


First the good news:

Fig. 1.  Way to go Washington, so redelicious! Kind of phoning it in Wyoming,
don't you think?  Did you really even have to try to win that one?

Then the better news:

Fig. 2.  Dang, Washington, you invaded! Also, Michiganders!
Get with it and EAT THE CARP!

HA! It turns out I live in the best place in the country to study invasive snails! Ima go do that, right now, or maybe just wait til Monday when the tide is better.

Species species of the Week week #4 OR Hiphopopotamus

Hippopus hippopus

(The Horse's Hoof Clam OR 

The Strawberry Clam OR 

The Bear Paw Clam)

Figure 1. What a wacky looking clam!!
Photo Credit: Mehmet Atatur

Figure 2.  Yup, wacky from this angle too!

Right, so the radness of the shell alone (Figs 1 & 2) is pretty much enough coolness for this tautonym to stand on, but there is so much more to Hippopus hippopus (Disambiguation: Did you mean "Hiphopopotamus"?) that makes it cool. And for that we need to see a picture of it in situ, up close:

Figure 3. Open live H. hippopus, looking even wackier

Go closer...

Figure 4.  Siphon and wacky mantle tissue.
Photo Credit: Artesub.com

Closer still...

Figure 5. Extreme Close-up. Reflective proteins in mantle tissue of Tridacna
Micrograph Credit: Griffiths et al. 1992

Too close, a little too close!

Figure 6. Dinoflagellates (non-algae algae) of the genus Symbiodinium.
They live in giant clam flesh!

There!  Living right in the mantle tissues of these Giant Clams are dinoflagellates (1),  phytoplankton of the genus Symbiodinium.  The genus name kind of says it all.  These  wiggly bulbous photophiles have a symbiotic relationship with the clams whereby they use sunlight to produce carbohydrates, which the clam then eats, and in return, they get a stable habitat in which to live and drink up the sun.  Free-living dinoflagellates, like all plankton, are at the mercy of the tides and currents and can get forced down to a depth beyond which they can obtain sufficient light to photosynthesize (= bitty dinoflagellates, wasting away).  By paying a bit of rent in the form of sugar to the clam, symbiotic dinoflagellates are assured that they will not be sucked into the deep.

Ok, so that's cool enough, but not unique.  This is roughly the same symbiosis as corals and our own local Anthopleura anemones (see really, really ... really cool research at Western on climate change and symbiosis).  

But!  What I learned just this week at a talk by Alison Sweeney (2) was that not only do the clams have algae all up in their skin, but they apparently also modify their own mantle tissue feed more dinoflagellates, and thereby get more sugar.  They're farmers! The iridescence you see in the mantle (Figure 4) is generated by iridocytes, cells with organized proteins all stacked up (Figure 5).  What are the iridocytes for?  There are a number of ideas that have been considered, including protecting the dinoflagellates from exposure to too much sun, which can cause chemical stress on both dinos and clams.  

However, modelling and experiments done by Dr. Sweeney and friends indicate that proteins in iridocytes forward scatter wavelengths of light that are useful in photosynthesis, deeper into the clam than it would otherwise go.  This is good news for the dinoflagellates and the clam (more light -> more photosynthesis for more dinoflagellates -> more candy for the clams!).  However, the iridocytes backscatter  the other wavelengths (like green), so we see green iridescence. So, it's possible that the clam uses iridocytes to improve their dinoflagellate husbandry.

Dang, clam, you pretty and smart!

References and miscellany:

(1) Pedantic note about pronunciation of this word: Neigh on a decade ago, it was STRONGLY emphasized to me by Greg Teegarden who learned it from his Academic forefathers/mothers that "Dinoflagellates" is pronounced "DEE-no" NOT "DYE-no".  The former is derived from Greek meaning "rotation", referring to the transverse flagellum that causes these guys to spin, while the latter signifies the Greek word "deinos", meaning "terrible" - like Dinosaur = "terrible lizard".   It seems to me that these are spinning, but not terrible, flagellates.  

(2) Most official website I could find for Dr. Sweeney, this is from Duke where she did her Ph.D. Currently at UCSB Institute for Collaborative Biotechnologies, headed to Penn Physics this fall. She has also done lots of work on coloring and iridesence and optic stuff in cephalopods. 

Species species of the Week week #3 OR Foaming with rage and bruised all over the chest

Grapsus grapsus

(The Sally Lightfoot Crab)

Dang, Sally, you pretty!
The whimsically named and colored Grapsus grapsus.

John Steinbeck will undoubtedly provide a much more interesting perspective on this whimsically named (in both Latin and common) Grapsus grapsus than I ever could.  So, I leave it to him to describe this tropical member of the Grapsid family:

Many people have spoken at length of the Sally Lightfoots. In fact, everyone who has seen them has been delighted with them. The very name they are called by reflects the delight of the name. These little crabs, with brilliant cloisonné carapaces, walk on their tiptoes, They have remarkable eyes and an extremely fast reaction time. In spite of the fact that they swarm on the rocks at the Cape, and to a less degree inside the Gulf, they are exceedingly hard to catch. They seem to be able to run in any of four directions; but more than this, perhaps because of their rapid reaction time, they appear to read the mind of their hunter. They escape the long-handled net, anticipating from what direction it is coming. If you walk slowly, they move slowly ahead of you in droves. If you hurry, they hurry. When you plunge at them, they seem to disappear in a puff of blue smoke—at any rate, they disappear. It is impossible to creep up on them. They are very beautiful, with clear brilliant colors, red and blues and warm browns.

…

Man reacts peculiarly but consistently in his relationship with Sally Lightfoot. His tendency eventually is to scream curses, to hurl himself at them, and to come up foaming with rage and bruised all over his chest. Thus, Tiny, leaping forward, slipped and fell and hurt his arm. He never forgot nor forgave his enemy. From then on he attacked Lightfoots by every foul means he could contrive and a training in Monterey street fighting has equipped him well for this kind of battle. He hurled rocks at them; he smashed at them with boards; and he even considered poisoning them. Eventually we did catch a few Sallys, but we think they were the halt and the blind, the simpletons of their species. With reasonably well-balanced and non-neurotic Lightfoots we stood no chance.

-The Log from the Sea of Cortez (1951)(1)

Hit Parade:

• Grapsus grapsus have been reported to remove the ticks from marine iguanas - how thoughtful, AND delicious!(2)
• Here is an educational video in Portuguese, complete with whimsical music. I certainly do not speak this language, but it's pretty footage and I do think I recognized the phrase "voracious predator".  If anyone wants to offer a translation of the narration...
• Our most common local Grapsids are Hemigrapsus oregonensis and Hemigrapsus nudus, which can be found on almost any salty beach around town, scuttling away from overturned rocks. My dog Jay used to think they were little chicken nuggets with legs.

References and miscellany:

(1) A highly, highly, recommended read. I enjoyed being reminded that I missed the golden days of ocean exploration and could still pretend I was doing reading for "work" by learning about beasties along distant coasts.

(2) Beebe, W. (1924).  Galapagos: World's End. New York: G.P. Putnam's Sons.