Beaten to the punch, again...

A clump of Eudistylia vancouveri, photographed at a location just to the west of the Elwha River delta

Every once in a while over the ten years that I've been diving at Elwha I would see something that struck me as special; an example of an interspecific relationship that I hadn't really anticipated.  

Let me start with a bit of background.  First, let me introduce you to one of my favorite invertebrates, the beautiful Eudistylia vancouveri, or Northern Feather Duster worm.  I'm into these inverts for a few reasons. First, they look like truffula trees, which is just cool.  Next, and perhaps most importantly, they are big, obvious and easy to identify underwater.  When we first started diving the Elwha I always felt a sense of relief counting Eudistylia, since I knew I was going to get it right.  More than anything, perhaps, that explains my appreciation for these worms.  

A complete E. vancouveri individual that we happened to dredge up with a sediment grab.  The scissors are full size.  The tube of this individual measured roughly 1 meter, and the worm almost 0.5 m. 

E. vancouveri is a special tubeworm, notable for how large and stout its tube is.  Diving near Elwha we would commonly observe individual tubes in excess of probably 20 cm...and that was just the bit sticking out of the substrate.  We couldn't really figure out how much additional tube there was below the substrate.  On a few occasions over the years we made futile efforts to dig an individual out of the substrate, hoping to actually measure one.  I dug some big holes underwater, and never was able to get to the end of one of these tubeworms. 

It wasn't until early this year that we collected a complete individual in a sediment grab...purely by accident.  The tube was over 1 meter in length, and the worm itself around 50 cm.  These are impressive worms.  

Looking up at the fronds of bull kelp.  Oh, and there are some fish too.

The other player in this story is bull kelp (Nereocystis leutkeana).  These are a bit better known - they are the fast-growing kelp that, under some circumstances, are able to grow all the way to the surface, where you can easily observe their buoyant bulb and fronds from a boat or kayak.  These bull kelp require (or so we told ourselves) hard substrate to attach to - ideally bedrock.  They can grow on smaller boulders and gravels, but as they grow and the cross-sectional area of their stipe and fronds increases, it becomes more and more likely that they will mobilize these coarse grains  After that, these kelps are on the move...and frequently won't survive the ordeal.

A common site near Elwha - Nereocystis attached to coarse clasts.  As the kelp grows it mobilizes the clasts and the algae no longer can stay in one spot.  This typically ends poorly.

So around Elwha it always struck me that one of the challenges for Nereocystis, and maybe even a limiting factor for its distribution, was finding available stable substrate. Every now and again, though, we would see enterprising Nereocystis taking advantage of the stability of E. vancouveri to find a place to hold in relatively fine substrates.

Nereocystis attached to and growing on Eudistylia.  This photo was shot near here.  This is a pretty energetic area - high currents and decent surge - and no bedrock.  Its likely very hard for Nereocystis to find stable substrate to hold on to in this area.  

This all came up for me after reading this article in the Hakai Institute's excellent magazine.  There is a lot to like about this - I love the story here about the serendipity of this discovery, and the convergence of an observation with a "prepared mind".  In this case Matthew Bracken was prepared enough to know how special the relationship that he was seeing really was, and to document it.   I wasn't - I thought it was cool, but wasn't prepared enough to know just how cool it was.  So, again; beaten to the punch.  Maybe there still is a chance though...is this the first documentation of this relationship with Nereocystis?