Columns, The Outside Story

Pond Eggs and Algae Have Beneficial Relationship

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photo by Kent McFarland
Egg masses with and without algae.

WHITE RIVER JUNCTION – Peer into a woodland vernal pool in New England right now, and you’re liable to find masses of developing spotted salamander eggs. Many of them have a green hue visible throughout the gelatinous mass. Most things lying in water eventually get coated in algae. But in 1927, Lambert Printz realized this was a special green alga only found on these eggs and formally named it Oophilia, meaning egg-loving, amblystomatis, from the genus of spotted salamanders.

In the 1980s, biologists wondered if there was more to the relationship between alga and animal than they initially thought. They found that spotted salamander embryos grown without green algae didn’t develop as quickly. The scientists believed that the alga might provide more oxygen for eggs in potentially oxygen-poor waters.

However, in 2011, biologists reported in the Proceedings of the National Academy of Sciences that they discovered green algae actually living inside the cells of developing spotted salamander embryos.

In an Indiana University press release, biologist Roger Hangarter said, “With the ability to use gene-specific probes, it is now possible to determine the presence of organisms that may not be easily visible by standard light microscopy. In the past, researchers looking with simpler light microscopy techniques than are available today failed to see any algae in the salamanders.”

This special symbiotic relationship is termed endosymbiosis, in which two species not only share living space, but one actually lives inside the cells of another. They found evidence of green algae in salamander oviducts, suggesting that transmission may occur from one salamander generation to the next via transmission through eggs.

If you want to learn about vernal pool ecology and how you can get involved in vernal monitoring, visit the Vermont Center for Ecostudies Vernal Pool Conservation program

Kent McFarland is on the staff of the Vermont Center for Ecostudies.

Kent McFarland

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