(bright music) - [Narrator] They are small gifts from the sea, (music continues) beautiful seashells that delight with their intricate form and stunning colors.

(music continues) (waves rushing) - [John] We all go to the beach and find these just exquisite shells.

It's a very common hobby, especially here in Florida.

- [Ruediger] Well, we use the word seashells kind of for two different things.

One is the shell itself, the skeleton, and the other one is essentially the group name for shelled marine mollusks, mostly snails and clams.

- [Jose] The shell is there from minute one, very microscopic at that point, and as the body of the mollusk grows, it will add more and more shell material, making the shell larger.

The shapes are super varied, and there's a lot of engineering that goes into that, you know, to make the shells resilient and strong.

- [Ruediger] This is external skeleton, and it's permanently attached to the living soft body inside.

In snails, it's usually one muscle.

In clams, it's often two or more.

(bright music) - [Narrator] There is an incredible diversity of species.

- [Jose] Mollusks, although they are kind of a poorly known group by regular folks out there, they're one of the largest groups of animals on the planet.

They are found everywhere.

- [Narrator] Scientists estimate there are approximately 50,000 shelled marine mollusks that have been described to date, with more than one new species being named every day.

- [Jose] We've just barely scraped the surface.

- [Harry] Some people estimate that only half the known species have been described, which is unfortunate, because some are going extinct as we speak, as habitats are altered, under the pressure of human populations.

- [Linda] The more you appreciate something, the more you'll try to protect it.

(compelling music) - [Jose] Mollusks and their shells, their lives have been intertwined with humans since probably the dawn of human life, and I think the first connection is food.

- [Ruediger] They have been used as tools or sacred objects in both daily life and in religion in many different cultures.

(compelling music) - [Narrator] Even today, their elaborate shapes and symmetry are often reflected in architecture, fashion, instruments, and jewelry.

But how do the living animals spend their lives, and what is their role in the ecosystem?

(dramatic music) - [Announcer] Major funding for this program was provided by the Batchelor Foundation, encouraging people to preserve and protect America's underwater resources.

Additional funding was provided by Trish and Dan Bell, and by the Parrot Family Endowment for Environmental Education.

(bright music) - [Narrator] In Southwest Florida, shelled mollusks have long played an important role, including with the Calusa.

- They were not an agricultural people.

They were basically fishing and gathering shells, and you can see that by their shell mounds, and also by the utensils and the ornaments they left behind.

- [Narrator] Today, the region is famous as a shelling destination, with Sanibel Island a longtime tourist favorite - [Jose] Sanibel Island is known as a mecca for shelling.

It's basically one of the places along the west coast of Florida where you may find huge amounts of shells, especially when you have cold fronts during the winter.

The winds that come from the north and northwest will cause the water to move in just so, so the shells are really piled up on the beaches here.

(compelling music) - [Narrator] Sanibel is also home to the Bailey Matthews National Shell Museum, the only accredited museum in the United States devoted solely to shells and the mollusks that make them.

(compelling music) - [Jose] They're very conservation minded.

The museum has a professional collection, a scientific collection like any natural history museum does.

(compelling music) - [Narrator] Further south in the Florida Keys, mollusks are also abundant.

The field museum's curator of invertebrates, Dr. Ruediger Bieler, has spent more than three decades studying the animals there.

While beach combers won't find many treasures in the Keys, the area is home to more than half of the species that occur along the eastern seaboard.

- (Ruediger) There are very few sandy beaches, and there are the reefs in front of the shore, so many of the deeper water shells don't reach us.

- [Narrator] Nonetheless, there are areas where living mollusks hide in plain sight.

- [Ruediger] One is Snipe Key.

It's a very nice kind of sandy beach environment up at the Gulf of Mexico coast of the lower Florida Keys.

The second location is on the ocean side of the lower Florida Keys.

It's a shallow water environment, and at a good low tide at the right time of the year, you can find up to, I would say, eight species of large shelled gastropods, literally in knee deep water, just walking around that little island.

A lot of the mollusks are very well camouflaged.

When they are kind of cleaned and they're sitting in a shell collection, they really stand out, and often in beautiful and dramatic colors, but when you see them in the environment with their beautiful aperture face down and the back overgrown with algae, they really blend into the background.

so sometimes even in very popular boating areas where a lot of people are, they don't realize that they're surrounded by many, many different species of mollusks.

(bright music) - [Narrator] Mollusks also live on coral reefs.

- Finding mollusks in the coral reef is not easy, because coral reefs usually have a lot of predators.

Mollusks have learned over a long time of evolution to hide very well.

- [Narrator] Most of the bivalves are filter feeders, while different species of gastropods have highly specialized diets that vary widely.

- When you look at the conchs, the different conch species, they largely feed on algae, so they are essentially the cows or sheep or goats of the area.

The predators have very different techniques.

- [Narrator] Some release an acid to weaken the prey's shell before drilling a hole in it with their sharp rasping organ.

Next, they inject substances into the prey before eating it.

- [Jose] There is a vampire snail that actually is one of the ones that attach themselves to fish, and they just suck the blood.

- [Narrator] And that's not the only snail attacking much larger and faster prey.

Some cone snails devour fish that are asleep.

(Ruediger) They actually need a very fast-working toxin cocktail - [Jose] Their teeth are modified into little harpoons.

- [Ruediger] That can analog to kind of a snake and deliver a toxin through that hollow tooth into the victim.

- They can paralyze a fish pretty fast.

It's microseconds of action there.

- The reproductive biology is also incredibly diverse.

- [Narrator] Most bivalves tend to spend their entire lives attached to a permanent surface, or safely buried in the mud or sand, so they release eggs and sperm that will fertilize in the water column.

- We have mollusks with separate sexes, and they have, you know, the female organs and the male organs, and they mate.

(bright music) - [Narrator] Some mollusk species change sex over the course of their lifetime, while others are hermaphrodites, having both male and female reproductive organs.

- [Jose] We have species that have larval stages in open water and the larvae may last like, a few months in seawater before it settles down to the bottom.

Then you have mollusks that the young will hatch from an egg capsule and begin crawling just like mom and dad did.

(bright music) - [Narrator] These egg capsules come in beautiful shapes and textures.

- [Jose] One example, which locally, is the most remarkable one, is the lightning whelk, and that one is the one that has a string of egg capsules, and the female will find an appropriate site, usually a sandy bottom, and with the foot, it will go deep in the sand and put a little anchor there and begin building that, and once it reaches the surface of the sand, then that's when the egg capsules begin being formed.

And it takes probably anywhere between a week and a couple of weeks sometimes for the female to deposit all that.

- [Narrator] Using a gland at the bottom of her foot, the female deposits a few dozen eggs in each capsule she makes, creating a string of 50 to 200 capsules.

- [Jose] And that's why it takes a long time.

The result is that long chain of capsules that look like a skin of a snake.

- [Narrator] These egg capsules protect the embryos from predators, while also carrying the nourishment they need to develop.

Eventually, the lightning whelks emerge as tiny, fully formed snails.

- [Ruediger] Mollusks have a very particular organ, the so-called mantle, and the mantle is essentially a tissue flap that can generate shell material.

This is how they build the shell in the first place when they kind of grow in that spiral, but it's also how they can repair things around the lip or even from the inside.

If something punches a hole and the soft body didn't get damaged, they can fill it in from the inside.

- [Narrator] The shells are made from calcium carbonate, which makes them highly susceptible to ocean acidification, a lowering of the pH in seawater caused by climate change, which makes less carbonate available to build and maintain shells.

- Limestone floating in vinegar is not a not a good thing.

(waves rushing) (compelling music) - [Narrator] Scientists and shell enthusiasts have treasured and studied seashells for generations, amassing large collections in the process.

To easily make use of all this valuable data, Ruediger started an effort known as the Eastern Seaboard Project.

(compelling music) - [Ruediger] We wanted to document the occurrence of molluscan species essentially from the Canadian border down to the Mexican border.

It's about 6,000 kilometers of coastline.

We predicted there would be about 3,000 species of mollusks that we would find, and that's from the shallow beaches to about 200 nautical miles out the exclusive economic zone of the United States.

And the amazing thing is that more than half of those species can be found in the Florida Keys alone.

(compelling music) - [Narrator] The project brings together multiple institutions that collaborate on digitizing and streamlining the vast information in their mollusk collections so that it's easily accessible online.

- [John] Most of what we're doing is making sure that it's electronically available, so typing in things that have not been typed into a database.

- [Jose] And then working a way to standardize, to normalize all the data so that we know when someone is you know, talking about species A, that it's species A throughout the collections, and not species B in collection Y and species C in collection Z.

- And then also adding georeference data, so adding latitudes and longitudes where you could actually pinpoint where something is from.

- [Ruediger] We started out with 15 collections.

These 15 institutions have more than 85% of the holdings for the eastern seaboard, so there was a good start, and we hope to add additional partners down the road.

- [Narrator] The ultimate goal is the ability to search all the collections at once.

- [Ruediger] We are building data aggregators, and one of those is Invert E Base, and that is a facility, essentially a super database, that taps into all our individual collection databases.

- [Jose] There are many, many different ways of using the collection records.

It can be really powerful.

- [Ruediger] So one of the things we are trying to do is by compiling literally millions of these data points over time, to understand changes over time, and then try to infer what that change might be.

Is it climate change?

Is it ocean acidification?

Is it pollution?

Is it overfishing?

Is it over collecting?

[Ruediger] Down here in the Florida Keys for instance, we can pick up in the distribution of specimens in museum collections when the Flagler Railroad was built, because suddenly, there was a lot of concrete poured into the Keys, and species that would not find a home here because there was nothing to attach to, suddenly increased their numbers, like oysters.

So you can ask questions about species distribution over time at a scale that was just not foreseeable quite some time ago.

-[John] Data is hard to find for somebody like a land manager that needs to get information quickly about how a species is doing now versus in the past, and this offers an opportunity to get that kind of data that is not available any other way.

- [Ruediger] You can suddenly analyze millions of data records - [John] And that is super exciting because it's liberating There's so much information available now, and becoming available so quickly, that right now is a terrific time to be interested in biology.

(bright music) - [Narrator] One thing that's unique in the mollusk world is how much researchers collaborate closely with shell collectors turned citizen scientists.

One of them is shell enthusiast and collector Dr. Harry Lee, a retired physician from Jacksonville, Florida.

- I have a general collection which spanned the entire globe and the entire phylum of the mollusks, but I have areas of focus like the Western Atlantic marine shells, particularly United States and Caribbean and so forth.

(compelling music) - [Narrator] Beginning in 2010, Harry started donating his collection in annual increments to the Florida Museum of Natural History in Gainesville, where it can be used for research and education.

- We're a global collection, so we have material from almost everywhere.

It is probably the second largest collection in the United States.

Collections like Harry's are extremely valuable 'cause they contain many species we don't have already.

Harry not only is a great collector, but he's also been very generous with his knowledge.

He has an extremely broad range of taxonomic knowledge in mollusks.

- He has a brain of the brain of several people joined together.

- I think I've named about 39 species, usually with a co-author.

- [Narrator] And Harry has also had 21 species named after him.

- [Harry] It happened without my knowledge and without my provocation.

- [Narrator] One of Harry's areas of interest are the tiniest shelled species.

- The micromollusks, particularly fossil marine micromollusks of various parts of Florida, mostly in the 3 million and younger years of age, I found that in order to get the full swath of biodiversity, I had to look at the little tiny ones, because in reality, about half the biodiversity resides in animals that create shells no more than 5.5 millimeters.

That's about a fifth of an inch maximum dimension when fully grown.

- It takes so much time and effort to find a micromollusk, that if you were just to rely on research collections, you would not have very many of them.

You know, it takes hundreds of hours of sorting under a microscope to find these things.

- [Narrator] Since 2013, Harry has volunteered in the museum's invertebrate paleontology division, where each week, he spends hours looking for specimens.

- I spend most of my hours at the dissecting microscope, going through prepared samples from fossil digs.

I've done it for estimated 3,000 hours now, and I find something novel almost every day I'm there.

It's exciting to see something that, you know, no one else has ever seen before.

- To have somebody with that kind of interest spending that many hours every week for decade upon decade is really, really amazing.

(compelling music) - [Narrator] Another citizen scientist who works closely with researchers is underwater photographer Linda Ianniello.

- I've been diving and doing underwater photography for over 30 years.

- [Narrator] Since 2015, Linda specializes in a relatively new and challenging activity known as blackwater diving.

Only a few areas in the world currently offer this experience, one of which is off the coast of Palm Beach, Florida.

(compelling music) - [Linda] Blackwater diving is very unique.

Black means it's at night, and we go about five miles offshore to where the ocean bottom is about 700, 750 feet, so you're diving in the water column.

It's a drift dive, so the boat puts up a lighted buoy and a 45 foot line, and it has lights at top and bottom roughly every 10 feet, so the divers follow the rig, and the bottom light's about 45 feet, so you shouldn't go any deeper, and the boat follows all these lights.

- [Narrator] The divers will drift for about an hour and a half before getting back on the boat.

During that time, they observe some rarely seen creatures.

Each night, tiny animals migrate up from the depths into shallower water to feed on the phytoplankton that occurs near the surface.

- And the theory is that in the dark, the predators, their eyesight can't see them as well, so they come up at night to feed, and then go back down in the early morning, and this is the largest migration on Earth that takes place every night in the ocean.

- [Narrator] The photographers come across all types of planktonic creatures, from fish and mollusk larvae, to animals that spend their entire lives in the water column.

- The mollusks as a whole are my favorite.

I like the sea angels, sea butterflies, and the veligers, they're just awesome.

Some of them have just stunning colors and you wonder why.

And there's a sea butterfly that has appendages that look like leaves.

What helped in its evolution to look like leaves?

Things like that I think are fascinating.

These creatures are small, they're one inch or less, a lot of them are transparent, so they need a lot of light to take the pictures and to focus.

They're hard to focus.

I usually say it's the most challenging underwater photography there is.

Your subject is constantly moving.

Remember, they're up in the dark for a reason.

They don't wanna be seen.

So you come along with these big lights shining on them, and they may book it to the surface or book it to the bottom, and they very seldom freeze, so you're chasing this subject.

I realized quite a while ago that I'm a hunter.

I like to find things, learn about them, identify them first.

- [Narrator] Many of the mollusk larvae Linda photographs look very different from their adult counterparts, which live on the sea floor.

- At this point, there's nobody that has identified the larvae and what they grow up to be.

- The fact that they may be photographing things that nobody ever saw before or ever collected, that's priceless.

- [Narrator] Scientists are helping to identify the larvae that have been described, which can be challenging.

- [Jose] Traditionally, the way you're collecting is plankton nets.

- And by the time it gets on the boat, all these animals that have these fancy appendages and frills and everything, they were all gone, and they had no idea what the animal looked like in the water column.

- We only knew them from being in little alcohol jars in museums with no color.

- [Linda] I started keeping pretty good records of everything that the scientists were telling us.

- [Narrator] Together with fellow blackwater diver and friend, Susan Mears, Linda published a book on the animals they photograph, identifying them whenever possible.

- People were coming and doing the dives and they were excited, but they get back on the boat and they say, "I saw all these things, but I don't know what it was," and so we started thinking, okay, we're starting to build up enough images and enough information that we could put together a book that would help, and specifically for our area.

You know, it's strictly things found here, so people doing these dives will understand and learn about what they're seeing.

- [Narrator] Occasionally, Linda will also collect some of the mollusk larvae she photographs for the Florida Museum of Natural History.

- And hopefully, someone will come along and be interested in figuring this out, probably based on DNA.

My whole goal is to help science and understand.

The other thing is make people aware of this environment, because there's companies that want to do deep ocean mining and trawl, 90% of the subjects that they start collecting are undescribed, so we don't know what's there, and it all has a purpose.

- [Jose] We do worry about the fact that species are not named fast enough to keep up with the potential for destruction of their environments.

(bright music) (waves rushing) (music continues) - [Narrator] Seashells with their beautiful shapes and symmetry have inspired humans since the dawn of time, but just as equally fascinating are the animals which make them, and their unique place in the web of life.

(bright music) (music continues) - [Announcer] Major funding for this program was provided by the Batchelor Foundation, encouraging people to preserve and protect America's underwater resources.

Additional funding was provided by Trish and Dan Bell, and by the Parrot Family Endowment for Environmental Education.

(bright music)