Soft sediments – they’re alive!!!

Square

On Aug 3, I told you about the dives we’d done to collect soft sediments.  Tube of macrofauna in ethanolSince then I’ve spent many an hour in the lab processing the samples we collected.  Processing involves (1) quantifying the volume of riprap-originating algal material in each sample, (2) quantifying sediment grain size, (3) identifying each type of shell hash, and (4) identifying and counting all macrofauna.

Macrofauna are organisms that live in soft sediment.  Until just a few years ago, I had no idea how many critters actually live embedded in sand and mud. From above, the soft sediment landscape appears barren, almost devoid of life.  But it’s actually alive in a way I never imagined – at a tiny scale.  After many hours of picking through sand and mud in my sediment cores, I am again amazed at the density and diversity of macrofaunal life forms.  They come in all shapes and sizes, colors and textures, life histories and strategies.  Worms, clams, snails, amphipods, ostracods, sea cucumbers, and more!  It’s overwhelming.

For now, I’m simply pulling specimens out of sediment samples and storing them in ethanol (as in the photo), but I’ll be identifying them over the coming months and look forward to sharing.  Their stories are bazaar, amazing, surreal – from vicious hunters with exploding mouth parts to little arthropods that spend their entire lives moving about the seafloor in the organic equivalent of a hamster ball. I’ll highlight my favorites as they arise.  Stay tuned!