Ask an Explorer

Questions were sent to the science party during this expedition. Selected questions and answers are offered below.

Question from: Rex Roettger, Science Teacher at the Ramey School, Puerto Rico

I was reading Peter Etnoyer's background essay about bamboo coral colonies growing over 30-ft tall on seamounts near New Zealand. What is the average size of the bamboo coral you are encountering on this trip? It was mentioned that one coral was estimated to be 70 years old. What methods do scientists use to calculate the age of these corals?

Answer by: Peter Etnoyer, Principal Investigator

Dear Rex:

Glad you're interested. We've encountered two types of bamboo corals so far. At the base of the seamounts, we are finding unbranched sea whips, called Lepidisis sp., and up on the shallow peaks, we are finding large candelabra-shaped Isidella sp. Both are about 4-5 ft tall. We age them by taking a slice through the proteinaceous node and counting the rings. The rings represent lunar cycles, though, not annual. We validate out estimates with Carbon 14 isotopes. For more information refer to the Gulf of Alaska 2002, July 14, 2002 article "What Species Is a Bamboo Coral?". This can be found on NOAA's Ocean Explorer Web site. Again, thanks for the great questions.

Sincerely,
Peter Etnoyer