Spotted salamander egg masses. (Photo by John Burns) Dr. John Burns of Bigelow Laboratory for Ocean Sciences will lead an online presentation called “From Roommates to Intimate Partners,” about the symbiotic relationship between algae and spotted salamander eggs and larva, on Tuesday, March 9 at noon, hosted by Merryspring Nature Center. Many Mainers are familiar with the "Big Night" that comes near the beginning of each spring, when yellow spotted salamanders migrate en masse from their underground hideouts to their spring breeding pools. In vernal pools they mate and lay their eggs, which swell to form a dense jelly mass holding around 100 embryos each. These eggs and embryos are colonized by a tiny green alga, which have adapted to one another to both benefit from this arrangement.