The Daily Bucket is a regular feature of the Backyard Science group, a place where everyone is welcome to note the observations you have made of the natural world around you. Fledglings, insects, blossoms, fish, climate, reptiles and/or amphibians: all are worthy additions to the bucket. Ask questions if you have them and someone here may well have an answer. All we ask is that you let us know where you're located, as close as you're comfortable revealing.

This is a continuation of sorts of my Dawn Chorus diary from yesterday.  It is a bucket of two week old events - hopefully that's OK.

Two weeks ago today my wife and I were on Cumberland Island, a barrier island in Georgia and a National Seashore.  The area had experienced heavy rain and storms for several days previously.  The weather had pounded the sand down hard and had washed a fair amount of debris up onto the beach.  One of the best things about walking on the beach is seeing what the ocean gives up and allows us land creatures to see.

Based on what I saw - I have three general observations to make.

1) Not surprisingly the species found on a coastal Georgia beach, bordering the open Atlantic where somewhat different than those on the northern Gulf Coast beaches I usually frequent.  Some common items were familiar such as the remains of Horseshoe Crabs (Limulus), Penshells (Atrina), and the ubiquitous cockles (family Cardiidae). Olive shells (family Olividae) were also common, something I have only seen a couple of times on Panhandle beaches.  Also knobbed Whelks (Busycon carica) which do not occur in the Gulf.

Hard to know how much of the difference is do to geography and how is due to chance, which I will discuss a bit more in the next section.

One of the most striking things on the beach were these rather dubious looking tubes.

It turns out they are the tubes of the parchment worm, Chaetopterus variopedatus.  This is a tube-dwelling polychaete worm (a marine relative of the earthworm) that pumps water through the tube and uses specialized segements to filter out food.  I've never seen this tubes before that I can remember but they were all over the place.

Occurring in smaller numbers were these Sea Cucumbers, probably Sclerodactyla briareus. I wasn't sure what they were at first because my primary experience with sea cucumbers are ones that are much firmer - more the consistency of a sea star.

Sea Cucumber
I think I have encountered these before but not a bunch at once.

Finally this was a one of a kind beach find for me.  A cow nose ray, a close relative of the eagle rays.

Cownose Ray on beach
2) My second observation is linked to the first.  It has been my experience that when you find one of something  on a beach you usually find several.  For example, the previous time I visited Cumberland we encountered four porcupine fish washed on the beach over the span of about a mile.  I have never encountered a stranded porcupine fish anywhere else at any other time in my life.  This is an extreme example but in my experience it isn't uncommon to see a bunch of one species washed ashore at one time and then not see them again at the same location and have other species washed up in future storms.  This seems counter intuitive to me but it appears to be a real phenomenon.  It also makes the sort of comparison of locations I tried above very suspect unless you have long term data from all locations.

3) My third observation may be related to my second.  Here is a scene on the beach.

Beach with debris
The beach here is thick with debris, mostly algal fragments.  But most of the beach was actually fairly clean with only a few scattered larger objects.  Given the flatness of the beach it was quite striking how the great bulk of the debris was concentrated in a few, very discrete spots.  Clearly the interplay between the waves, wind, current, and sand is complicated.

The effect of minute variation on water movement can be seen in the formation of drainage systems, like miniature watersheds, in the debris itself.

debris pattern
Debris pattern
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