Thursday, June 25, 2009

A Little Bend in the Creek

When I have the time, I like to spend a few minutes in one loction to see what I can find. I decided to spend a little time at this spot in the creek before the flow completely stops. A nice gravel bar has developed on the inside of the curve where the creek takes a turn to the left.

The force of water during high flow conditions is expended against this limestone bedrock on the right bank. The bedrock layers have a definite lean to the left as a result of the meteor strike 300 million years ago. You can get a good idea of the shallowness of the soil over this rock. The exposed roots of the dead cedar stump show how they are stopped by the impenetrable limestone.

Here’s the source of the Field Horsetails that are now circling my water garden and charging out across the driveway.

The water flow has really slowed in this small pool. It won’t be too long before the water stops moving all together. Small pools like this are often dry by early September.

There are several aquatic creatures living here. The easiest way to find the swimming and floating animals is to watch for their shadows on the creek bottom. Water Striders are present everywhere there is enough water on which to float. The shadow shows the size of the dimples made by the Water Strider’s feet pushing down on the surface of the water. Small fish are also present. These are probably young Northern Creek Chubs. The mature chubs make their way up the creek to breed during high water in spring. You can see one fish just below the Water Strider and one a little ways to the left.

Some of the Streamside Salamander larvae are still in the creek. The little fish are large enough to cause problems for these larvae. The salamander is big enough to eat the fish if it could catch them, but if given the chance, the fish will feed on the salamander’s gills and any other little parts they can get hold of.

I picked up a 3 inch flat rock and found some interesting life beneath.

This is a hellgrammite, the larva of the Fishfly.

Here's the larva of a Dusky Salamander. It will spend its entire life beneath rocks in or near the creek.

I didn’t notice this mayfly larva when I took the picture. I was checking the picture of the hellgrammite and salamander larva when I spotted the image of the 3 tail filaments common to mayfly larvae. You can see the tail on the left in this picture and you can see the eye spot on the right. This particular species is shaped to resist the water currents as it clamors around on the rocks grazing algae.

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