SALAMANDER + ALGAE = CURIOUS SYMBIOSIS

[Reproduced from THE  JOURNAL OF EXPERIMENTAL BIOLOGY, after New Scientist]

Intracapsular algae provide fixed carbon to developing embryos of the salamanderAmbystoma maculatum

1. Erin R. Graham1,*, 
2. Scott A. Fay1,3, 
3. Adam Davey2 and 
4. Robert W. Sanders1

+Author Affiliations

1. ¹Department of Biology, Temple University, Philadelphia, PA 19122, USA
2. ²Department of Public Health, Temple University, Philadelphia, PA 19122, USA
3. ³Berkeley Initiative in Global Change Biology, University of California, Berkeley, CA 94720, USA

1. ↵* Author for correspondence (erin.r.graham@temple.edu)

• Received June 25, 2012.
• Accepted September 10, 2012.

SUMMARY

Each spring, North American spotted salamander (Ambystoma maculatum) females each lay hundreds of eggs in shallow pools of water. Eggs are surrounded by jelly layers and are deposited as large gelatinous masses. Following deposition, masses are penetrated by a mutualistic green alga, Oophila amblystomatis, which enters individual egg capsules, proliferates and aggregates near the salamander embryo, providing oxygen that enhances development. We examined the effects of population density of intracapsular O. amblystomatis on A. maculatum embryos and show that larger algal populations promote faster embryonic growth and development. Also, we show that carbon fixed by O. amblystomatis is transferred to the embryos, providing the first evidence of direct translocation of photosynthate from a symbiont to a vertebrate host.

NB  The embryos release waste material, which the algae feed on. In turn the algae photosynthesise and release oxygen, which the embryos take in. Embryos that have more algae are more likely to survive  and develop faster than embryos with few or none.