Tuesday, September 06, 2011

A Question and Perhaps a Puzzle

I have a question for the geo- and paleo-minded folks out there:

How deep can a benthic diatom burrow?

Now the reason I ask this question is that the worm Paraonis makes spiral burrows (pictured above) that have been identified as "traps" for diatoms (Minter et al, 2006). This means that the diatoms must be able to burrow to at least the depth that the sprials are produced but I have read that diatoms have only been identified as burrowing up to 3 mm (which is a big deal for such a small creature) (Hay et al, 1993) but Paraonis burrows have been identified up to 10 cm down (Risk and Tunnicliffe, 1978). Quite a contrast.

This means that either they are wrong (this is not a diatom trap), they are eating other things (which they don't think so), or diatoms are burrowing deeper than I can find literature on.

So I was wondering if anyone has any knowledge of diatom burrowing depths. If you do please comment or send me an email.

Hay, S.I., Maitland, T.C., & Paterson, D.M., 1993, The speed of diatom migration through natural and artificial substrata: Diatom Research, v. 8, p. 371-384.

Minter, N.J., Buatois, L.A., Lucas, S.G., Braddy, S.J., & Smith, J.A., 2006, Spiral-shaped graphoglyptids from an Early Permian intertidal flat: Geology, v. 34, p. 1057-1060.

Risk, M.J., & Tunnicliffe, V.J., 1978, Intertidal spiral burrows; Paraonis fulgens and Spiophanes wigleyi in the Minas Basin, Bay of Fundy: JOURNAL OF SEDIMENTARY RESEARCH, v. 48, p. 1287-1292.


  1. I'm puzzled why diatoms--photosynthetic organisms--would burrow at all. Wouldn't this be a bit like installing solar panels in a cave?

    And assuming diatoms are found at the bottom of these worm burrows, is it not possible that the worms are capturing the diatoms at or near the surface and pulling them down into their burrows to eat? Is there evidence that the diatoms are actively burrowing to that depth, or are they simply passive items that the worms themselves are pulling down to 10 cm depths?


  2. I am not sure why they burrow but I know that:

    1. The do burrow, there are enough papers confirming this and

    2. They seem to burrow at night then come up during the day so it is linked to the light cycle.

    The reason they do may be linked to wastes left on the surface but I am not entirely sure.

    As to the worms and the burrows, that is the question I am trying to figure out. I was trying to determine if the reason that the worm burrows were spiral was to act as diatom traps as was proposed previously or if there could be some other reason. I also might have the depth of the burrows wrong but I don't think I am that far off if I am.


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