Tide Pools

I sometimes wonder what has led me into a career in science. It wasn’t my fifth grade teacher, and certainly not my freshman high school science teacher, whose course I scraped through with a D minus. Neither my mom or dad were scientists, although my mom liked to bird watch, and my dad, an ex-merchant marine captain, owned a work boat that he chartered out to scientists doing coastal surveys and research, but I was too young then to go along. I think it may have been tide pools.

As a youth I liked to spend idle time lying on my belly on Maine granite with my face a few inches above a tide pool watching what was going on. Barnacles were at first sealed in their shells, but then would begin opening and reaching and retracting their tentacled hands. What were they catching? How quickly could I move my hand before they would retract? Was it just the shadow of my hand that made them retract or its movement? Miniature shrimp were always swimming about, sometimes attached to one another. What was all that about? Whelks and periwinkles moved slowly across the bottom with their little antenna sticking up. What were they eating? How come it was easier to dislodge them when they were in the water than when they were on the exposed ledge? If it was a larger tide pool, perhaps there would be sea anemones waving their colorful tentacles, or the occasional crab stalking about. And the colors, so different from the surrounding rock: deep reds, rusts, shades of orange, some yellows and greens, but no blues. The tide pool was a living world contained in itself, yet recreated twice a day by the tide. Did the animal populations change twice a day too?

It seemed to me a world only limited by my imagination. Every tide pool is different, if not in the creatures living there, then in it’s geography. One of my favorites was shaped like the United States, or at least the lower forty-eight with a little Florida-like peninsular sticking out — filled with baby mussels. This tide pool had the gentle curve of the west coast, and the long straight reach from west to east of the northern border. Maine and Texas were both rounded off a bit, but the center was deep, I could just touch the bottom. Large mussels were there.

Its taken many years and a lot of training to become a scientist, and knowledge has filled in many gaps that my imagination used to fill in before. But I am happy to say that I still enjoy a good lie down at the edge of a tide pool. The colors are no less tantalizing, although I think I understand why there are few blues; the creatures no less compelling. Now I wonder what kind of microbial biofilms the periwinkles are grazing on, and if they might select certain types over other ones. I even imagine that the populations of microbes in the tide pool are somehow different from the ones in ocean that comes and goes everyday. I also hope the ‘miniature shrimp’, which I now know to be full grown amphipods, are enjoying themselves.

David Emerson

About David Emerson

David Emerson is a professional scientist at the Bigelow Laboratory for Ocean Sciences who studies bacteria that live literally between a rock and a hard place. The views expressed here are his alone.