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Sea School to take on sand dollar study

By Staff | Oct 7, 2015

The Sanibel Sea School will be undertaking a longterm sand dollar population research project, due to the uncommonly high amount of juvenile sand dollars being found just off of Sanibel and Captiva. Sanibel Sea School

Penny for your thoughts?

How about a sand dollar?

That’s exactly what the Sanibel Sea School will be delving into with the start of their longterm research study on the sand dollar off the coasts of Sanibel and Captiva Islands.

The study was motivated by the obvious high density of juvenile sand dollars being found just off of Buttonwood Beach and Captiva and also due to the fact, the marine organism has been researched very little over the course of time.

“We are in the process of beginning a multi-year sand dollar population project on Sanibel and Captiva, while collaborating with some researchers, one being from the University of South Carolina and the other from the Canterbury Schools in Fort Myers,” said Sanibel Sea School co-founder and Executive Director Dr. Bruce Neill. “Our goal is to answer the questions of the survival, growth rates and the population dynamics of sand dollars.”

Sand dollars earn their name due to the fact they look like a round white coin and is one to four inches in diameter as adults. The sand dollar is just as common as sea stars and starfish on the beaches of Florida.

The sand dollars which are being found off of Sanibel and Captiva in abundance, are juveniles, which were born around June of this year.

“Right now, they are about 22 millimeters in diameter and we will be able to watch them grow up to 100 millimeters,” Dr. Neill said. “We believe this will be the highest density of sand dollars in one area which has ever been reported. In some instances, we have found up to 100 juvenile individuals per ever square meter.”

Dr. Neill and his Sea School staff also want to enlist young researchers and helpers, as well as retired folk who would be interested in learning about the sand dollar during the study.

“We would love to fit this study into small little aspects of working with younger kids, such as in their science fair projects or school projects,” Dr. Neill said. “We would like to produce publishable science data, which will contribute to the body of knowledge that scientists know about sand dollars and what we know about our inner-tidal.

“Someone doesn’t need to be a qualified researcher to be a part of this, they just need to be interested in learning about this subject.”

The grand goal is to turn the study into a 10-15 year investigation into sand dollars’ population.

Sand dollars reproduce by releasing eggs and sperm into the water, where they will join and develop into free-swimming larvae. Through the maturation process, they will eventually develop a hard skeleton, where they will drop to the bottom and live the rest of their lives.

Larvae also can clone themselves and that occurs in do in response to increased predators.

“That can be a kind of a negative thing, because they are cloning themselves out of desperation and not doing it because it’s the natural thing to do,” Dr. Neill said. “Whether the frequency they are doing that is an indicator of water quality or not, we do not know.”

Predators of the sand dollar larvae include different types of fish, as well as sea stars.

“These sand dollars are more complex than what we give them credit for,” Dr. Neill said. “But for how popular they are, we know very little about them.”

Much like mollusks, sand dollars can give an early indication of the health of the ocean.

“Sand dollars are like the canaries of the ocean, they give warnings early on if there is something wrong,” Dr. Neill said. “This is an exciting time for us and I suspect within a two-year period, we have a lot of answers, which will also lead to many more questions.”

Some important aspects which could come out of the study include involving scientists from around the world, as well as hosting graduate students who want to do a study on the sand dollar here.

“A million different questions can come up while doing this,” Dr. Neill said. “We are absolutely dedicated to the longevity of the project. And that’s what we will tackle in the next couple of years. We hope to bring in other researchers or grad students in here to study, then help facilitate that by having access to the field.”

To learn more about the Sanibel Sea School and what it has to offer and the programs available for children and adults alike, visit their website at www.sanibelseaschool.org/.