Tuesday, February 27, 2018

Under a glaring sun

Where the intertidal flats are mostly flat slabs of sandstone, critters that usually hide in the sand under rocks when the water recedes, quickly burrowing deeper when their rocks are flipped, either just put up with unfiltered sunlight, or cling tightly to the underside of what few stones are available. There's nowhere to run.

A half-dozen hermit crabs and a Wosnesenski's isopod struggle to stay in the shade of a trio of mussels. I replaced their stone roof gently where I found it.

The sand is a thin dusting on the sandstone. There's no shelter for the critters that can't run and hide elsewhere.The anemones here are under about a half-inch of water.

The green algae, the red seaweed, and the anemones don't mind the sunlight. Even at full tide, they're exposed to it, just slightly shaded by the clear water.
This green algae is probably the same one that pollutes my aquarium, always growing first on the walls closest to the light. The pink-tipped green anemones also benefit from sunlight; they do not photosynthesize, being animals, but carry symbiotic algae in their tissues; these algae produce enough food for themselves and some over for the anemone that hosts them.

2 comments:

  1. Down at our marina there are so many isopods on the rocks that the rocks themselves look almost alive. - Margy

    ReplyDelete
  2. Your marina is a treasure-trove of critters!

    ReplyDelete

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