Monday, March 23, 2015

High and Dry

"In the spring a young salamander's fancy lightly turns to thoughts of.....," well you know.  With apologies to Alfred, Lord Tennyson.

Out hiking yesterday I looked for spotted salamanders in several ponds.  In one with steep sides I found 40 egg masses, all several inches above the water line. There had been a big runoff from the melting snow followed by rain and the pond had gone from brim full to its normal level over several days, stranding the hopes of the libidinous parents to a future of dessication. 

Large egg clusters of spotted salamander eggs in the leaf litter - note waters edge above.
These gelatinous masses are surprisingly adherent, the eggs sealed together as well as clinging onto the ground.  Many were adherent to a dead branch that had initially been in the water.  Lifting the branch, they all held on until I could toss it into the pond.

Egg masses hanging from a branch
As discussed in a past blog, these globs are a wonder of nature.  The thick clear jelly coating around the eggs protects them from drying out but inhibits oxygen absorption. This is especially important when the pond dries up, as happens to ephemeral ponds which are critical for many amphibians.  A pond that disappears every year means that no fish or even bull frogs live there, a critical source of predators.  Temporary wet pools (ephemeral) means more babies survive.

Imagine being an egg in the middle of the mass, far away from the edges where the dissolved oxygen in the water exists.  Spotted salamanders have an interesting and unique symbiotic relationship with a single celled green alga, Oophila amblystomatis.  The algae takes up carbon dioxide and nitrogen waste products from the eggs and photosynthesizes oxygen.  The eggs acquire the needed oxygen, continuing to develop into larvae while producing more carbon dioxide and the cycle continues.  The New Scientist article calls this The First Solar-powered Vertebrate.  The relationship has been known before but now there is proof that the algal cells exist inside the cells of the salamanders themselves.  The algae is thought to be contained in the salamander germ cells and thus transmitted to each new generation.*

They are all back in the water, preparing for drier times ahead.

*From this 2013 blog.

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