1st post -- Questions about micro shells in beach sands

[srsilva]

Hello,

    I know almost nothing about seashells but in 1996 I visited Vanuatu where my father was stationed during WWII. While there I collected a bit of beach sand from several localities just as keepsakes.  When I got home and examined them under a binocular microscope I discovered quite a variety of tiny shells. The best came from south Tanna and the sand is fairly coarse, maybe 2-3mm average.   Among the shells a coworker pointed out for me some foraminifera and radiolaria but there were many more familiar looking forms as well.  I’ve thought about this sand over the years and I have several questions related to it.  I would be grateful for any answers that can be offered.

1.  Is there a common term or phrase used to refer to sand like this (with included shells), in other words, what might I use for search terms on the web?

2.  Are many of the little cones and other shells likely just juvenile forms of much larger animals or are they actually micro species?

3. Would the community of shells found in a particular sand be very representative of a particular part of the world? I’m sure there would be differences between tropical and arctic waters for instance but would one expect to see differences between oceans along the same latitudes or even differences between neighboring island groups or between islands in the same group?  Could an expert deduce approximately where a sand was from based on the community of shells?

4.  Can anyone recommend some introductory literature about micro-sized shells, preferably not too technical?  I would like to know a bit about their occurrence, lifestyles, and environments and be able to identify at least the most common species.  I have no practical use for this information other than I think it would be interesting and enjoyable.

5.  Are there people who collect sands like this specifically for the shells?  Is there anywhere I might purchase some shelly sands from various parts of the world?

Thanks much,
Steven

[paul monfils]

Hi Steve,  Welcome to the website.

 Such fine beach-collected material is often referred to as "beach drift" or "grunge".  The shells in such material are often a mix of adults of minute species and juveniles of larger species.  In some localities the tiny species predominate, while in other places juveniles are more common.  Juveniles, as you might expect, are also commoner at certain times of year, shortly after they hatch. I recall going to one beach in the spring where there were what appeared to be long ridges of black sand, which turned out to be millions of 3-4 mm juveniles of a species that reaches about an inch in length.

The geographical distribution of minute species is a lot like the distribution of larger species.  Some species are widely distributed, and the probable locality might not be able to be narrowed any further than "Indo-Pacific Region" or "circumboreal".  Other species might be restricted to "Caribbean", "Mediterranean" or "Red Sea".  And some might be endemic to a particular land mass, especially an island or island group, like Hawaii,  Japan or Madagascar, or even Easter Island.  In a particular sample there might be primarily species of wide distribution, yet the presence of even a couple of species of more limited distribution might help narrow the options for possible localities. This would however require the input of a specialist.  Most experienced collectors could look over a group of larger shells and give you at least a general locality.  But not many collectors are equipped to do so with microshells.  I certainly am not.

The literature on such microspecies is unfortunately sparse as well, which is one reason among several why there is not more interest in such species.  There are some folks who like to collect such tiny specimens, in fact there is one lady I know of who likes picking them out of the grunge, ends up with many more shells than she needs, and periodically offers vials of such shells to interested persons free.

I would recommend that you also post a query on Conch-L.  I'm pretty sure you will get some feedback there from microshell enthusiasts.  They like to trade material from different localities.  I don't know if you have access to such material in your present location.  But some folks may be happy to sell you some, or just give you some.  Conch-L also has searchable archives where you can find past discussions on a topic, and possible contacts, by searching for a keyword.  When searching, be sure to search for both "beachdrift" and "beach drift"; "microshells" and "micro shells".

<a href="http://www.conchologistsofamerica.org/conch_l" target="_blank"><!-- m --><a class="postlink" href="http://www.conchologistsofamerica.org/conch_l">http://www.conchologistsofamerica.org/conch_l</a><!-- m --></a>  

"Let's Talk Seashells" is another good source of information and contacts.

<a href="http://z14.invisionfree.com/Conchologist_Forum/index.php?act=idx" target="_blank"><!-- m --><a class="postlink" href="http://z14.invisionfree.com/Conchologist_Forum/index.php?act=idx">http://z14.invisionfree.com/Conchologis ... hp?act=idx</a><!-- m --></a>  <span class="petit">--Last edited by Paul Monfils on 2009-04-05 07:26:08 --</span>

[srsilva]

Hello Paul,

    Thanks very much for the detailed answers!  I was thinking that my questions were probably too long for a first post.  The info is just what I wanted.  When I saw the little shells I also spent time picking them out and separating them into categories to get a feel for how common the various types were, then I begin to wonder who they were.  There was something relaxing and satisfying about doing that.  I'll definitely check out the sites you mention and see what I can find.  Thanks again.

                                                  Steve