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Photosynthetic Fractionation Of Oxygen Isotopes, A Study With Elodea Canadensis, Glen E. Martin

Theses and Dissertations

Bubbles of oxygen from Elodea canadensis were collected and found 5 per mil enriched in 0-18. This confirms the results of both Dole and Vinogradov, who found 0-18 enrichment of photosynthetic oxygen relative to its source, i.e. water. Photosynthesis and respiration appear to have produced the Dole effect, i.e. the 22 per mil 0-18 enrichment of atmospheric oxygen relative to ocean water, its probable source. These results are contrary to findings for both UV photolysis and electrolysis of water both evolving oxygen found depleted in 0-18.

Adaptive Mechanisms For Aquatic Existence In Freshwater Turtles, Oscar Gloor

Honors Theses

Naturalists have often marveled at the ability of some air-breathing vertebrates to remain underwater for long periods of time (that is, "long" from man's reckoning). Seals, penguins, porpoises, and whales are all noted fro their ability to use oxygen stored in various ways to permit them to "stay under" for many minutes.

The return of vertebrates, which evolved on land, to an aquatic existence has been a much discussed subject from an evolutionary standpoint. That there are many advantages to life underwater is easily seen simply by the fact that, according to fossil records, terrestrial life arose from the sea. …