Florida's Blue Holes: Oases in the Sea - Full Episode

Summary

The video script delves into the mysteries of Earth's least explored domain—the ocean. Covering 75% of the planet, it reveals Florida's 'blue holes,' deep underwater openings teeming with life. Scientists and divers explore these oases, investigating their geological origins, ecological significance, and potential links to nutrient sources for red tides. The research uncovers microbial activity, unique ecosystems, and the possibility of an underground network, emphasizing the importance of understanding and preserving these underwater phenomena.

Takeaways

• 🌍 The ocean covers 75% of Earth and remains largely unexplored, with more known about the moon and Mars than the seafloor.
• 🐟 In Florida, divers discovered 'blue holes' in the Gulf of Mexico, which are deep, dark openings in the seafloor teeming with marine life.
• 🕳️ Blue holes vary greatly in size and depth, with some extending over 400 feet into the earth, and are understudied environments.
• 🤿 Technical divers are crucial for exploring these deep holes, requiring specialized training and equipment to reach such depths safely.
• 🔬 Scientists and volunteer divers are conducting expeditions to study these blue holes, focusing on their geology, biology, and potential ecological impacts.
• 🏞️ There is speculation that blue holes may have formed over 10,000 years ago when lower sea levels exposed more of the Florida shelf.
• 🌡️ Measurements show that pH and temperature drop within blue holes, and nutrients are elevated, suggesting a unique chemical environment.
• 🔬 The benthic lander, a high-tech device, is used to survey sediment and water at the bottom of the holes, providing continuous data over 24 hours.
• 🧪 Sediment core samples reveal high levels of ammonium and phosphate, indicating intense microbial activity and a potential nutrient source for the ecosystem.
• 🦠 Microbial life within the blue holes, including a significant presence of archaea, could have implications for understanding life in oxygen-poor environments.
• 🌐 The connectivity between blue holes and Florida's groundwater system, as well as their role in nutrient cycling and marine life, is still under investigation.

Q & A

What percentage of the Earth is covered by oceans?

Oceans cover 75% of the Earth's surface.

Why are the depths of the ocean still a mystery despite extensive space exploration?

We know more about the surface of the moon and Mars than we do about the actual seafloor due to the vastness and inaccessibility of the ocean depths.

What are the blue holes and where were they discovered?

Blue holes are deep, dark openings in the seafloor discovered beneath large gatherings of fish in the Gulf of Mexico.

What is unique about the life found in blue holes?

Blue holes are unique as they are teeming with life, acting as vibrant oases in an otherwise barren ocean desert.

What is the significance of exploring these blue holes?

Exploring blue holes is significant as these environments are understudied and could potentially hold undiscovered ecosystems and geological features.

How deep do blue holes extend into the earth?

Blue holes can extend down over 400 feet into the earth, with some having only a small entrance that opens up into a large room.

What role do technical divers play in the exploration of blue holes?

Technical divers, who are certified to go to extreme depths, are essential for the exploration and research of blue holes, as they can reach depths recreational divers cannot.

What are the challenges faced by divers exploring blue holes?

Divers face challenges such as the need for specialized equipment, the use of trimix gas blends to avoid nitrogen narcosis and oxygen toxicity, and the risks associated with long decompression times.

What scientific tools and methods are used to study the blue holes?

Scientists use underwater cameras, benthic landers equipped with various instruments, sediment core samples, and electrochemical analysis to study the blue holes.

What is the potential environmental impact of nutrients found in blue holes?

While nutrients may attract marine life, there is a concern that they could also contribute to phenomena like red tide blooms, which can have adverse effects on marine ecosystems.

What is the connection between the microbial activity in the sediment and the ecological island formed by blue holes?

The microbial activity in the sediment breaks down organic carbon excreted by fish, creating nutrients that fertilize phytoplankton at the surface, thus sustaining a cycle of life within the blue hole.

Why are archaea, microbes living at the bottom of blue holes, significant for astrobiology?

Archaea, which can survive without oxygen, represent a rare finding that could provide insights into potential life forms on other planets that also lack oxygen.

What is the current understanding of the water movement within blue holes?

Research suggests that water is moving from the bottom of the blue hole to the overlying water column, but further investigation is needed to determine if there is an exchange with Florida's underground water system.

What is the ultimate goal of the research on blue holes?

The ultimate goal is to provide a comprehensive understanding of the ecological and environmental importance of blue holes and their role in the larger marine ecosystem.

Outlines

00:00

🌊 Ocean Exploration and Blue Holes Mystery

The script introduces the human quest for discovering new worlds, which extends to the unexplored depths of Earth's oceans. Despite extensive knowledge of outer space, our understanding of the ocean floor is limited. In Florida, divers have discovered 'blue holes'—submerged sinkholes teeming with marine life. These underwater phenomena, with varying sizes and depths, are understudied and their connection to Florida's groundwater system is yet to be determined. The script highlights the allure of deep-sea exploration and the collaborative efforts of institutions and divers to uncover the secrets of these blue holes.

05:01

🕳️ Formation and Discovery of Blue Holes

Experts hypothesize that blue holes were formed over 10,000 years ago when lower sea levels exposed more of the Florida shelf. Rainwater, flowing through the limestone, created channels and caves that eventually collapsed to form these holes. In 2005, Jim, a character in the script, received a grant to study these offshore features. His team confirmed the existence of over 20 blue holes, each sustaining a unique ecosystem and attracting a variety of marine species. The script details the process of exploration, including the technical challenges and the interdisciplinary approach required to study these phenomena.

10:03

🦈 Diving Deep into the Blue Holes for Research

The script describes the process of exploring Amberjack Hole, a sinkhole 30 miles off Sarasota, Florida. Divers must be highly trained to reach depths of over 300 feet, using specialized equipment and gas mixtures to avoid the dangers of deep-sea diving. The team uses a combination of underwater cameras, citizen scientists, and technical divers to document marine life and the physical characteristics of the blue holes. They also collect water samples to analyze the chemical composition and nutrient levels, which are crucial to understanding the ecological significance of these underwater oases.

15:03

🧪 Analyzing the Microbial and Chemical Processes

Scientists are investigating the microbial and chemical processes within the blue holes by collecting and analyzing sediment samples. They use a benthic lander equipped with instruments to measure nutrient flux in the sediment and water. The analysis reveals high levels of ammonium and phosphate, indicating intense microbial activity. This finding suggests that the blue holes may be self-sustaining ecological islands, with the physical structure of the holes supporting a cycle of organic carbon and nutrients that nourish the marine life.

20:04

🌌 Unraveling the Microbial Communities and Their Implications

The script delves into the study of microbial life within the blue holes, focusing on the unique conditions that create distinct microbial communities. The discovery of archaea, microbes that can thrive in oxygen-depleted environments, has implications for astrobiology and our understanding of potential life on other planets. The research also examines the stratification of these communities and the chemical composition of the water, including the presence of hydrogen sulfide, which can be toxic to marine life.

25:07

🔍 Ongoing Research and the Future of Blue Hole Studies

The final paragraph discusses the ongoing research into the blue holes, including the investigation of their connection to Florida's underground network and the broader implications for the Gulf of Mexico's ecosystem. The script emphasizes the importance of continued exploration and analysis to better understand these underwater phenomena. It concludes by acknowledging the incremental nature of scientific discovery and the support from various foundations for preserving and studying America's underwater resources.

Keywords

💡Blue Holes

Blue holes are underwater sinkholes or caves with deep, broad vertical shafts that open suddenly in the seafloor. They are often circular in shape and can be several hundred feet deep. In the context of the video, blue holes are described as 'vibrant oases in an ocean desert,' indicating their unique ecological significance. The script discusses the allure of exploring these mysterious formations, which are 'booming with life' despite being in the depths of the ocean.

💡Seafloor

The seafloor refers to the bottom of the ocean, which is a vast, relatively unexplored area that covers 75% of the Earth's surface. The video emphasizes that we know more about the surface of the moon and Mars than we do about the seafloor, highlighting the importance of exploring these depths to uncover Earth's remaining secrets.

💡Marine Life

Marine life encompasses the diverse range of organisms that inhabit the ocean, including fish, corals, and various invertebrates. The video script describes the abundance of marine life found within blue holes, such as 'goliath grouper, schools of jack, turtles, and even whale sharks,' suggesting that these areas serve as important ecological hotspots.

💡Technical Divers

Technical divers are highly trained individuals who are certified to dive to extreme depths, often using specialized equipment and gases. The script mentions that these divers are crucial for exploring blue holes, as they are capable of reaching depths of '300, 400 feet' and conducting scientific observations in these challenging environments.

💡Trimix

Trimix is a breathing gas mixture used in technical diving, typically consisting of oxygen, nitrogen, and helium. The video explains that divers use trimix to avoid the harmful effects of breathing air at depth, such as nitrogen narcosis and oxygen toxicity. This allows them to remain lucid and functional during deep dives into blue holes.

💡Microbial Activity

Microbial activity refers to the biological processes carried out by microorganisms, such as bacteria and archaea, which can influence nutrient cycling and energy flow in ecosystems. The video discusses the intense microbial activity found in the sediment of blue holes, which is responsible for creating a nutrient-rich environment that supports a diverse array of marine life.

💡Nutrient Flux

Nutrient flux describes the movement of nutrients in and out of a particular environment, such as the sediment at the bottom of a blue hole. The video script mentions that scientists are studying the nutrient flux in blue holes to understand how these areas might be contributing to the productivity of the surrounding ocean, potentially influencing phenomena like red tide blooms.

💡Sulfide

Sulfide is a chemical compound that contains sulfur. In the context of the video, it is mentioned that the bottom of the blue hole has high sulfur content, indicating the presence of hydrogen sulfide, a poisonous gas to most marine life. This finding suggests that the unique chemical conditions within blue holes can create distinct microbial communities adapted to these environments.

💡Archaea

Archaea are a domain of single-celled microorganisms that are distinct from bacteria. The video script reveals a surprising discovery that archaea make up almost 50% of the species living at the bottom of the blue hole. This finding is significant for astrobiology, as it provides insights into how life might exist in oxygen-poor environments on other planets.

💡Radioisotopes

Radioisotopes are variants of chemical elements that are radioactive, meaning they decay over time. In the video, research geologist Chris Smith uses radioisotopes to analyze water samples from blue holes, providing clues about the age and movement of the water. This technique helps scientists understand whether there is an exchange of water between the blue holes and the broader geological matrix of Florida.

Highlights

The ocean covers 75% of the earth, yet we know more about the surface of the moon and Mars than the seafloor.

In Florida, divers discovered deep dark holes, known as blue holes, teeming with life in the Gulf of Mexico.

Blue holes vary in size and depth, with some extending over 400 feet into the earth.

These underwater environments are understudied, lacking basic information for characterization.

Expeditions are being conducted by multiple institutions and volunteer technical divers to explore these environments.

The exploration of blue holes is likened to space exploration due to the lack of previous measurements and observations.

Investigations into whether blue holes are connected to mainland Florida and the groundwater system are being pursued.

Blue holes may have formed over 10 thousand years ago when sea levels were lower, exposing more of the Florida shelf.

Divers have verified over 20 different blue holes, each with diverse ecosystems.

A multidisciplinary team began exploring Amberjack Hole in 2019, revealing a biological hotspot in the Gulf of Mexico.

Technical divers use trimix, a blend of gases, to avoid the harmful effects of deep diving.

Scientists are analyzing the chemistry of the water and sediment in blue holes to understand their ecological role.

Nutrient levels in blue holes are elevated, potentially attracting marine life but also posing concerns for red tide blooms.

A benthic lander equipped with instruments is used to survey the sediment and water at the bottom of the holes.

Sediment core samples reveal intense microbial activity and chemical processes within the blue holes.

DNA analysis shows distinct microbial communities within the blue holes, with archaea making up almost 50% of species at the bottom.

The discovery of archaea in blue holes could have implications for astrobiology and understanding life on other planets.

Research aims to determine if there is an exchange of water between blue holes and Florida's underground geological matrix.

The exploration and understanding of blue holes contribute to the broader knowledge of seafloor conditions and ecological importance.

Transcripts

The desire to discover new worlds has taken humans deep into outer space.

But planet earth still holds its own secrets - with much left to be discovered in its liquid

depths.

The ocean covers 75% of the earth; we don't know much about them.

We know about the surface of the moon and Mars better than we know about the actual

seafloor.

In Florida, reports of large gatherings of fish in the Gulf of Mexico piqued the interest

of divers.

They discovered an unlikely find beneath the fish … deep dark holes opening down into

the seafloor.

You're swimming along on the bottom and it's very sandy.

You'll see some fish go by, some random organisms around, but then you approach these holes,

and all of a sudden, it's just booming with life.

These openings, commonly called blue holes, vary in size and depth.

Some have only a small entrance that’s five feet wide that opens up into a large room,

while others extend down over 400 feet into the earth.

But the allure is, well you wonder, what's a little deeper and a little deeper, and pretty

soon, you're in 150 feet or so.

And there's more to see.

So you want to go deeper and deeper and find out what's going on.

These environments are so understudied, that we don't even have the basic information to

just characterize them.

Now, multiple institutions and volunteer technical divers are teaming up for expeditions to explore

these environments like never before.

It's definitely exotic.

The ability to really get in these systems and make human observations, which is really

important, is pretty analogous to a space exploration.

Nobody's taken measurements.

Nobody's looked at the fauna.

Nobody's looked at the geology or where they flow.

It's all exploration.

We're interested in whether or not these holes are connected to the mainland Florida.

Is there any connection through the groundwater system?

Is any of the freshwater getting out to these holes?

If they are a source of nutrients, which could potentially be a possible source of nutrients

for red tide, we don't know.

Why are these deep holes in the seafloor?

And what makes them vibrant oases in an ocean desert?

Major funding for this program was provided by the Batchelor Foundation, encouraging people

to preserve and protect America’s underwater resources.

And by the Arthur Vining Davis Foundations, strengthening America’s Future Through Education.

Additional funding was provided by The William J. & Tina Rosenberg Foundation and by The

Do Unto Others Trust.

Florida is a state born from the sea.

The peninsula sits on a foundation of porous swiss cheese-like limestone, making it home

to many springs, caves, and sinkholes.

Highly trained divers from around the world explore these liquid labyrinths for a taste

of adventure.

I had an interest in them, and I had been a diver for a long, long time and I've been,

since the mid-seventies been diving in springs and sinkholes and caves on land.

Mote Marine Laboratory’s Jim Culter is part of a small percentage of divers that venture

into the planet’s intricate underground cave system.

He first heard about similar features that existed offshore from fellow cave divers.

What if there were these offshore springs, uh, with freshwater, what kind of community

would you have on those sites?

And where would they come from?

Some experts believe these so-called blue holes may have formed over 10 thousand years

ago when sea levels were much lower, exposing a larger portion of the Florida shelf.

It rains, and water sinks in the ground and flows through this porous limestone.

It will slowly dissolve the calcium carbonate and form these cracks and crevices; they'll

start to form channels and little tunnels.

And that might form caves, and springs and the sinkhole basically is an underground cave

that the ceiling collapses.

In 2005, Jim received a grant to begin to quantify and characterize the blue holes that

fishermen had reported between 25 and 50 miles offshore.

So we would go out and try to find them, and we’d dive in them to see how far they went,

to see how big they were.

Jim and a team of exploration divers verified over 20 different holes, all with diverse

ecosystems attracting goliath grouper, schools of jack, turtles and even whale sharks.

It's like this biological hotspot out in the middle of the Gulf of Mexico.

What is causing these oases to be out there?

You know, why do all these animals love being there?

To learn more about these mysterious holes, a team of multidisciplinary experts joined

forces in 2019.

They began by exploring Amberjack Hole - a sinkhole located 30 miles off Sarasota.

Amberjack Hole is found at 114 feet below the surface and opens down to depths beyond

350 feet.

It's a little bit of a journey to get out to the hole.

It takes a good two hours depending on which boat you're on.

And, and once we're out there, the first thing we have to do is anchor the boats and make

sure they're in place over the holes.

We're working with citizen scientists.

So, we depend very heavily on tech divers to be able to accomplish this research.

We need divers who are certified to go to extreme depths, like 300, 400 feet.

It's a very different dive site from traditional diving.

A lot of people have some apprehension just because it's this big black hole in the bottom

when you go there.

Recreational divers are able to reach the opening of the hole at 114 feet on a single

tank of air, but to get to the bottom of the hole, divers must prepare for a dive that

will take up to 3 hours and that requires more gear.

Technical divers also use a blend of gas containing oxygen, nitrogen, and helium, called trimix,

to avoid the harmful effects of breathing air at depth.

You add helium to your mixture for two reasons.

One, you want to get rid of as much nitrogen as possible because nitrogen is what causes

nitrogen narcosis, which sort of affects your rational facilities, you know, makes it a

little harder to think straight and underwater.

Using the trimix you can remain lucid and can do your work as a scientist, you can be

more functional with deeper dives.

The drawback of course, when you go deeper is it just takes you much longer to get back

to the surface, a little more risk involved.

The addition of helium also helps reduce the risks of oxygen toxicity and decompression

illness that are potential threats during long, deep dives.

But if you obey the rules and be careful, it’s a very good scientific tool that can

be utilized for exploration.

How was it?

Nice!

Not bad!

Scientists are visiting the site in the spring and the fall to record any potential changes

between seasons.

One of their objectives is to survey marine life in the area.

We have a contraption that’s an underwater camera on PVC, where we can take a video going

along this transect.

And so, we do that around the rim and we also do it vertically going down into the hole.

And then so we’re seeing so far as we start swimming the transect …

A lot of sponges, a lot of those are sponge, the orange encrusting are sponges.

That’s a- the white things are colonial tunicates.

Experts later analyze the video to identify the types of organisms found in and around

the hole.

The first 20 or 30 feet below the rim is highly productive, it has a lot of sponges, there’s

corals.

You see fishes and crabs and bivalves of different types.

It’s a very diverse area.

And then as you go down into the hole, the zones start getting less diverse and more

cold water tolerant, like lower light tolerant type organisms.

Until it’s maybe, perhaps down to where it’s just more microbial type organisms.

The videos show there is more sargassum in the spring versus the fall.

Additionally, a strong green layer in the fall suggests higher levels of chlorophyll

and nutrients around the rim.

Let’s do both.

Scientists also collect water samples from the base of the hole up to

the surface.

My main focus is looking at the chemistry, and to see if it's providing anything extra

to the surrounding water.

Is it a nutrient source, is it a sink?

The Gulf of Mexico is a very oligotrophic system, meaning there's not a whole lot of

nutrients just out there all the time.

Just in our initial exploratory dives, we know that pH drops as you go into these holes,

temperature also drops, and we know that nutrients are elevated in these hole systems.

And so we’re trying to understand why, what’s causing this.

While the nutrients may be attracting marine life, scientists worry they could also have

a potentially adverse effect.

If it is a source of nutrients out in the middle of the Gulf, that would be really important,

especially since we know that a lot of red tide blooms form offshore.

To determine if there is a link between these holes and red tide blooms, experts say more

research is needed.

I’m setting up everything to check the lander.

Another group of experts from Georgia Tech and FAU Harbor Branch custom-designed a high-tech

device called a benthic lander, which surveys the sediment and water at the bottom of the

hole.

The benthic lander looks like almost like the moon lander or something that we would

put in space.

It's also got a lot of instruments on it.

For this particular lander, we typically lower it on the seafloor from a crane on the ship.

In this case, with the hole being so narrow it’s a pretty small target when you think

about waves and things like that moving a ship around, the ship isn’t really able

to get the lander down there.

Since Amberjack Hole’s diameter is only 75 feet, divers must guide the lander into

the hole.

The lander weighs four or 500 pounds.

So this thing sinks fast to the seafloor.

We added flotation foam to it to make it completely neutrally buoyant so that the divers could

physically maneuver it underwater and get it down into the hole.

That's something new that we never tried before.

So, we're a little bit anxious about it.

See if it’s going to work.

Technical divers can only stay at a depth of 300 feet for a short period of time, whereas

the lander can continuously collect data over a 24-hour period.

One component called a “benthic flux chamber,” samples nutrients, carbon, and oxygen that

transfer, or flux, in and out of the sediment.

Think about like taking a coffee can and inverting it on top of the sediments.

Now you have a good little volume of water.

And we have syringes that take samples from that little parcel of water every four hours

and they're sampling both inside the chamber and outside the chamber.

Outside the chamber is sort of a reference, like a background.

Inside the chamber tells us how much is actually coming from the sediments themselves.

And then also we have this, a, um, electrochemical analyzer we call it.

These electrodes actually allow us to monitor, uh, things like oxygen, sulfide, dissolved

iron, dissolved manganese.

Once the experts determine the amount of nutrients and other elements accumulating inside the

chamber, they can calculate the total amount of nutrients and other elements fluxing in

and out of the sediment at the bottom of the hole.

These measurements tell the scientists more about the microbial and chemical processes

that occur in the sediments at different depths.

To obtain additional information, Jim and volunteer technical divers also collect sediment

cores.

So these are sediment samples.

They came from the bottom of this hole particular hole at about 310 feet deep.

And there is kind of what we call a debris pile at the bottom.

This amount of sediment could represent, you know, perhaps hundreds of years of, of sedimentation.

Jordon will be looking at the chemistry of the sediment and see how it's functioning

and so we'll take it back and get it analyzed.

One core is used for further electrochemical analysis, while a second core is sectioned

to determine how levels of nutrients and other elements change with depth.

So we're pushing the mud out using a piston and we section it in small intervals.

We then spin it in a centrifuge for 10 or 20 minutes.

We separate mud on the bottom, water on top, we pour that water off and then we filter

it.

We can use these pore water samples and actually conduct our analyses.

Jordon and his lab run a variety of analyses, including measuring grain size – a necessary

step to model how nutrients may be fluxing coming out of the sediment.

We want to know if it's clay, if it's sand, if it's silt, we want to know the actual distribution

of the grains and the mud.

How does it compare in the hole and how does it compare out of the hole?

The next measurement we do is organic carbon, we basically weigh the sediments before and

after burning.

We're measuring how much carbon, hydrogen, and oxygen is lost.

It's just sort of a snapshot of how much food is there.

This carbon feeds microbes living in the sediment.

Additional analysis of the sediment samples showed ammonium and phosphate found in the

sediment increased dramatically with depth.

These same nutrients also accumulated in the benthic flux chamber.

Usually, when you see a profile like that, it means that you have a flux outward.

Sure enough, the nutrient measurements show that the bottom water of the blue hole is

enriched in ammonium.

So, we're almost certain that a large portion of this is coming from the sediments themselves.

These results signify intense microbial activity in the sediment – an unexpected finding.

It's like the blue hole itself is actually responsible for creating this ecological island.

So now it's sort of a chicken or the egg problem, right?

Because you have this hole, and because the hole forms a shelter for fish, you have a

lot of fish living there.

The fish excrete, the fish die.

They deliver this organic carbon; it collects in this blue hole.

Microbes break down the organic carbon and then excrete more nutrients, which fertilize

the phytoplankton at the surface above the hole, which creates food for animals higher

up the food chain.

So the cycle is just sort of really sustained by the physical morphology, the geology of

this blue hole.

A team of biologists from Georgia Tech is closely studying the microbial life inside

the blue hole to see how it might differ from the surrounding ocean.

We're looking at both sediments from the bottom of the blue hole and water column samples

from the bottom all the way up.

DNA analysis of these samples makes it possible to determine what species of microbes are

present and what functional roles they play in the ecosystem.

We see some really interesting things about this blue hole.

The oxygen is really, really low in the water column.

Okay, so let’s plot graph.

Jordon found oxygen levels decrease dramatically to 10% just below the rim of the hole.

They then briefly increase again at 260 feet before falling to zero just above the debris

pile.

Wow, those smell.

We noticed it was really sulfidic at the bottom.

We could smell it in our water samples.

The divers could smell it when they were down there.

Jordon’s lab confirmed the bottom of the hole is very high in sulfur content.

When there's no oxygen in the environment, microbes can get creative and use other types

of chemicals to breathe.

They're breathing sulfate, and they're producing sulfide.

Hydrogen sulfide is a poisonous gas to most marine life that may become trapped in the

blue hole and die.

So our communities from the water column are very different between the surface, middle

and deep layers.

And they are represented by three distinct microbial communities.

And this is really interesting to us.

It means there’s not a lot of mixing.

It means things are very stratified.

We’re trying to get better resolutions that we can tell where exactly that switch happens

and does it correspond to a switch in oxygen or in sulfide?

Nastassia and her team made another surprising discovery- microbes called archaea make up

almost 50% of the species living at the bottom of the blue hole.

This incredibly rare finding could have implications for astrobiology.

If we’re interested in life on other planets that don't have oxygen, how might things be

living there?

Maybe this microbe has enzymes that help it breathe without oxygen and we're going to

find that on a planet one day and we'll know how these things are living because we have

examples of microbes that are living that way here on earth.

Much remains to be revealed about the mysterious blue holes in the Gulf of Mexico.

One of the remaining uncertainties is if these blue holes connect to a larger underground

network and if that network connects to Florida’s mainland.

And then the question is it a static system or is it a moving system or is there some

kind of exchange?

That's where my part comes in.

We’re going to take two samples in the blue hole and then one right at the rim.

To understand where the water in the hole is coming from and where it might be going,

research geologist Chris Smith analyzes radioisotopes found in water samples.

The radioisotopes we're using are naturally occurring, they exist in geologic materials

that make up our continental crust and oceanic crust.

So what we hope to get an idea of whether or not there's movement of the water, either

from the aquifer matrix to the blue hole and, or, the movement of the water from the blue

hole up into the overlying water column.

Chris pumps 50 liters of water over a fiber and collects water samples from a hand lowered

bottles to analyze various radioisotopes.

By knowing how long it takes for certain radioisotopes to decay, Chris can determine the relative

age of the sampled water.

So it's kinda like an internal clock so we can use it to kind of measure how long it's

been either moved away from its origin point or how long it’s been in transit from some

other location.

In the open ocean, some of the first samples we collected, it was below our detection limit

actually.

It was so low.

But at 60 meters and below, we were picking up concentrations that were probably a hundred

to a thousand times greater than our limit.

And so there is that enrichment at those depths relative to the water that's sitting right

at the surface.

Chris’s findings suggest water is moving from the bottom of the blue hole to the overlying

water column.

But further investigation is needed to determine if there is any exchange of water with Florida’s

extensive underground geological matrix.

Many secrets remain under the sea.

But scientists are one step closer to understanding these enigmatic blue holes and why they serve

as ecological oases in the Gulf of Mexico.

The ocean is not just kind of the coastline and then a flat desert, you know, everything

in between the coastlines is just boring and flat.

And these blue holes are just one example of that.

I think it's important to better understand what's actually out there on the seafloor.

It's really important for us to sort of establish and map out these conditions, unravel any

sort of connections and establishing the environmental and ecological importance of these blue holes.

By us going out here and taking these initial measurements, we may be able to justify future

exploration.

We can take kind of this methodology that we're coming up with, with how to analyze

these holes, how to characterize these holes and bring that to other holes in the future

and maybe even to see if there's differences from the northern Gulf of Mexico to the southern

Gulf of Mexico or east to west.

People ask, you know, “what's the major discovery, what's the big finding?”

And as a scientist, you know that there's very few big deals that are found out all

at once.

Mostly it's a very slow process that builds on previous research one little bit at a time.

And the ultimate goal is to provide a better understanding of the big picture of how things

work.

Major funding for this program was provided by the Batchelor Foundation, encouraging people

to preserve and protect America’s underwater resources.

And by the Arthur Vining Davis Foundations, strengthening America’s Future Through Education.

Additional funding was provided by The William J. & Tina Rosenberg Foundation and by The

Do Unto Others Trust.