Sunday, November 18, 2007

How tiny mud shrimp save Bay of Fundy mud flats

With the amount of water moving in and out of the Bay of Fundy with our tides several times a day, you may well wonder why mud doesn't get constantly sucked out the of Bay. Our small mud shrimp, Corophium voluntator, plays a role here too. I'm certainly no mud scientist but let me try to explain:

-their burrows compact mud flat sediment and actually cement together the particles lining the walls. This has the effect of creating a forest of erosion-resistant chimneys in the mud (see image).
- slightly more indirectly...shorebirds eat copious amounts of shrimp who feed on microscopic diatoms. Diatoms secrete a glue-like substance that makes sediment particles stick together and reduces their likelihood of being swept away by moving water. So by being 'food' for shorebirds, mud shrimp numbers are periodically reduced enabling the diatoms to flourish and strengthen the mud.
- mud shrimp also defend their mudflat habitat from invasion by salt marshes. By eating diatoms they keep the mud surface too unstable for colonizing plants to establish themselves. Constant burrowing and feeding by mud shrimp also buries the seeds of the invaders preventing them from germinating, or uprooting any that do.
Who knew?!

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