Everyone has noticed the intense weather that crossed the United States in recent years. Tornadoes are hitting communities throughout the Midwest, but are also hitting places like Seattle, southern California, and even recently Pensacola Beach. Thunderstorms, though common, are occurring in waves. Typical summer days here in the panhandle include afternoon thunderstorms, but recently there have been daily squall lines beginning as early as 9:00am. I was recently camping out west and we encountered three hailstorms. Though these do occur out there, they were becoming a common thing and were also encountered in multiple states. And of course, there are hurricanes. Some are more intense and increase intensity as they come ashore, instead of decreasing as has been the rule over the decades.
This squall line formed early in the morning. One of many morning thunderstorms formed over a period of a week in the summer of July 2023.
Photo” Rick O’Connor
Many have pointed the finger at climate change as being part of the reason why these intense weather events are increasing, and climatologists have said for decades this could happen. To better understand what is driving these storms, I decided to grab one of my old college textbooks from the shelf and read what actually forms and fuels these weather events. The Nature of Violent Storms was published in 1961, and reprinted in 1981, by Dr. Louis Battan. Though many things that were unclear at the time of the writing have been discovered, the mechanisms that generate and fuel these storms were understood.
The mechanism that begins storms is convection cells within the air rising from the earth’s surface. The air moving over warm land or water warms as well and begins to rise. The rising air lowers the air pressure at the surface and is called a low pressure system. We associate low pressure systems with storms. These storms form due to unstable air masses in this rising column of air. The greater the temperature difference between the warmer air near the ground, and the cooler air in the upper atmosphere, the more unstable the air becomes and the faster the column of air rises. As the air rises it begins to cool, become denser, and falls back to earth like a water fountain shooting water into the air. This is the convection cell we have heard about.
However, if the air mass holds a lot of moisture (humidity) the release of heat from this humid air mass rising in the column can warm the environmental air mass surrounding it enough to cause the rising air mass to continue higher into the atmosphere increasing its speed while doing so. We can see this as cumulus clouds building over the landscape and, if humid enough, you can literally watch the thunderhead build. If supplied with enough water vapor and heat, these thunderheads will grow all the way to the tropopause (the lower layer of the stratosphere where the atmosphere itself begins to warm, not cool) and form the “anvil” shape of a thunderhead we are all familiar with. As a college student taking coastal climatology (the class this book was associated with) we would sit outside of Dauphin Island Sea Lab at mid-afternoon and bet on which thunderhead would reach the tropopause first.
The upper layer of the lower atmosphere is quite cold. Here the releasing water vapor condenses into rain droplets, ice, and often hail. They fall back towards earth. Much of the ice and hail melt before reaching us but under intense conditions this frozen precipitation can reach the earth’s surface as hailstones, some being as large as three inches across. One storm we encountered in Colorado this year had hailstones about the size of a large marble. We heard that at a nearby amphitheater the hail reached the size of golf balls and many who were there to see a concert (and there was no cover to hide) were taken to the hospital.
A hail storm encountered by the author in Colorado.
Photo: Rick O’Connor
The one common denominator in the formation of such storms is the presence of a warm landmass or water body. The warmer these land masses and water bodies are, the more energy there is for the enhanced convection and severe storm formation. And these land masses, and water bodies are getting warmer.
Hail stones are formed from ice that manages to remain solid as precipitation in very unstable air masses. They can reach three inches across.
Photo: Rick O’Connor
What has changed is the atmosphere itself. There are gases within the atmosphere that allow solar rays to pass through reaching the surface of the earth, but do not allow the warmed air caused by the warming of land and sea from this solar radiation to escape back into space – the so called “greenhouse effect”. This is actually good; it keeps our planet at a warmer temperature than it would be if these gases were not present and allows life to exist here. However, an increase in these “greenhouse gases” can increase the overall temperature and create problems – intense storms being one of them. The surface of the planet Venus is around 900°F. Even though the planet Mercury is closer, Venus is warmer due to the heavy amount of greenhouse gases in its atmosphere. At temperatures like this, it is understandable that life does not exist there, and scientists do not believe it could. Getting scientific instruments to the surface of Venus is difficult due to the large amount of sulfuric acid in the clouds, much of this coming from intense volcanic activity there.
The greenhouse effect.
Image: NOAA
On Earth, our temperatures are climbing – slowly, but climbing. As the atmosphere warms due to the greenhouse effect, it increases the temperature of the land mass and water bodies. Increased temperatures in Pensacola Bay have triggered some die offs of oysters, and the warming Mobile Bay has increased the number of jubilee’s occurring there. Remember, high water temperatures mean low dissolved oxygen levels. Increased surface temperatures will create more unstable air masses and a breeding ground for the formation of vortices that can, and do, lead to more intense thunderstorms and tornadoes. Surface temperatures are increasing in locations where historically such weather events have not been common, like Seattle. Recently, I had to make a trip to a department store at one of our local malls. Leaving the house, as I crossed our wooden deck and walked through the yard to the truck, it was definitely warm – it was July. However, when I arrived at the store, where all was concrete and asphalt, the temperature difference was striking. It was MUCH warmer. Actually, at the store front it was almost unbearable. In many of our large cities, and even in smaller ones, we have converted much of the natural landscape to concrete and asphalt, which is increasing the surface temperatures even more, and enhancing unstable air even more. We have all heard that large cities create their own weather, and it is true.
So…
How do we turn this around?
I see two paths. (1) Reduce the source of the heating – greenhouse gases. (2) Mitigate the impacts of the heating.
There are several sources of greenhouse gases, and these have been discussed in other articles, but certainly the use of fossil fuels is a major one and reducing our dependency on these would be a good start. But we are moving very slowly on this, the will to do it just is not strong enough.
To mitigate the impacts, we would need to re-think how we grow and develop the landscape. Even today, many of the new subdivisions I see clear all of the vegetation, place the houses close together with little or no green space, use asphalt roofs, and replace little or none of the vegetation. It seems our development plan does not have the will to make some much needed changes in planning either. There are many ways in which we can develop our landscape to help mitigate the warming that is occurring. Many researchers at the University of Florida have been working on this for many years. For ideas and suggestions, just contact your county extension office.
Based on the 2021 Intergovernmental Panel on Climate Change’s report, we may be past the tipping on sea level rise, but we are not on other negative impacts of climate . It is understood that with any mitigation efforts right now, there will be a lag time of several years before things begin to turn around, it is not too late. We can do this.
When snorkeling the grassbeds of the Florida panhandle encountering a reptile has a low probability, but it is not zero. Of all the reptiles that call this part of the state home, few enter marine waters and most of those are very mobile, moving up and down the coast heading from one habitat to another. In fact, there are no marine reptiles that would be considered residents of our seagrasses, only transients.
The one species that you might encounter is the green sea turtle (Chelonia mydas). This is the largest of the “shelled” sea turtles and has a vegetarian diet. With a serrated lower jaw, they can be found grazing in the seagrass beds feeding on both the grasses and the species of algae found there. The carapace length of these large reptiles can reach four feet and they can weigh up to 400 pounds. Their coloration is similar to that of the loggerhead sea turtle (Caretta caretta) but their heads are smaller and there are only two large scutes between the eyes rather than the four found in the loggerheads. The colors of the skin and shell have shades of brown, yellow, orange, and some black and can be quite beautiful. The name “green” sea turtle comes from the color of their internal fatty tissue. Feeding on a diet of seagrasses, it becomes green in color, and this was discovered by early fishermen who hunted and consumed this species. It is the one used most often in what is called turtle soup and is actually farmed for this dish in other countries.
The green sea turtle.
Photo: Mile Sandler
Like all sea turtle species, they are born on the Gulf side of our barrier islands. If they successfully hatch, they work their way to the open water and spend their early years in the open sea. Some have been associated with the mats of Sargassum weed floating offshore, feeding on the variety of small invertebrates that live out there. They will also nip at the Sargassum itself. As juveniles they will move back into the coastal estuaries where they begin their vegetarian lifestyle. As adults they will switch time between the open sea and the grass filled bays. Once unfortunate side effect of feeding in our grassbeds is the frequency of boat strikes. There are tens of thousands of motored vessels speeding through our grassbeds and the turtles surfacing for air can be targets for them. Our hope is that more mariners are aware of this problem and will be more vigilant when recreating there.
Another turtle who IS a resident of the estuary is the much smaller diamondback terrapin. Though terrapins much prefer salt marshes they will enter seagrass beds, and some spend quite a bit of time there. Terrapins prefer to feed on shellfish so, moving through the grassbeds it is the snails and bivalves they seek. Because of their size they feed on the smaller mollusk. A typical terrapin will have a carapace length of about 10 inches and may weigh two pounds. They will take small crabs and shrimps when the opportunity is there, and they are known to swim into submerged crab traps seeking the bait. Unfortunately, being air breathing reptiles, they will drown after becoming entrapped. It is now required that all recreational crab traps in Florida have bycatch reduction devices (BRDs) on each of the funnel openings to reduce this problem. Many studies, both here in Florida and elsewhere, have shown these BRDs do not significantly reduce crab catch and so you can still enjoy crabbing – just not while catching terrapins. Encountering one snorkeling would be a very rare event, but – particularly in the eastern panhandle – has happened.
Diamondback terrapin.
Photo: Rick O’Connor
A third reptile that has been seen in our grassbeds is the American alligator (Alligator mississippiensis). Preferring freshwater systems, encounters with alligators in an open seagrass bed are rare, but do happen. There are plenty of freshwater ponds on some of our barrier islands that the alligators will use. They have been seen swimming out into the seagrass beds and often will cross the bay, or Intracoastal Waterway, to mainland side. They have also been seen swimming near shore in the Gulf of Mexico. Though they can tolerate saltwater, they have a low tolerance for it and do not spend much time there.
Alligators are top level carnivores feeding on a variety of wildlife. Like most predators, they tend to seek and capture the easiest prey. Most often these are fish, reptiles, or small mammals. But they will take on large birds or deer if the opportunity presents itself. Despite their natural fear of humans, they have taken pets and also have attacked humans.
Having only canines in their mouths, they must grab the prey and swallow it. Lacking molars, they cannot chew. So, more often than not, they select prey they can swallow whole. If they do grab a larger animal, they are known to drown the creature in what has been termed the “death role” and cache it beneath the water under a log (or some structure) where it will soften to a point where they can cut small pieces and swallow it. All of the alligators I have seen in our grassbeds were definitely heading somewhere. They were not spending time there. After heavy rains the salinity may drop enough to where they can tolerate being out there longer and encounters could increase. But they are still rare.
Alligator
Photo: Molly O’Connor
I will mention here that there are several species of snakes that, like the alligator, are swimming from one suitable habitat to another – crossing the seagrass in route. All snakes can swim and encounters in brackish water are not unheard of. I have several photos of diamondback rattlesnakes (Crotalus adamanteus) swimming across the Intracoastal Waterway between the mainland and the islands.
Eastern diamondback rattlesnake swimming in intracoastal waterway near Ft. McRee in Pensacola.
Photo: Sue Saffron
Encounters with reptiles are rare in our seagrass beds but pretty exciting when they do occur. There is certainly no need to fear swimming or snorkeling in our bay because they are so rare. But maybe one day you will be one of the lucky ones who does see one.
One of the community science volunteer projects I oversee in the Pensacola area is the Florida Horseshoe Crab Watch. The first objective of this project is to determine whether horseshoe cabs exist in your bay – FYI, they do exist in Pensacola Bay. The second objective is to determine where they are nesting – we have not found that yet, but we have one location that looks promising. One of the things my volunteers frequently find are the molts of the horseshoe crabs. Many keep them and I have quite a few in my office as well. One volunteer was particularly interested in the fact that they even molted and that they could leave this amazing empty shell behind and yet still be crawling around out there. So, I decided to write an article explaining the process in a little more depth than I typically do.
Horseshoe crab molts found on the beach near Big Sabine.
Photo: Holly Forrester.
I titled the article “The Molting of Crabs” but it could be the molting of any member of the Phylum Arthropoda – they all do this. The Phylum Arthropoda is the largest, most diverse, and successful group of animals on the planet. There are at least 750,000 species of them. This is three times the number of all other animal species combined. One thing unique to this group is the presence of an exoskeleton.
The exoskeleton is made of chiton and is secreted by the animal’s hypodermis in two layers. It provides the protection that the calcium carbonate shells of mollusk do but is much lighter in weight and allows for much more movement. Arthropods have jointed legs, hence their name “arthropod – jointed foot”, to enhance this movement even more. The entire body is covered by this exoskeleton.
The outer layer is thin and called the epicuticle. It is composed of proteins and, in many arthropods, wax. The inner layer is the thicker procuticle. The procuticle consists of an outer exocuticle and an inner endocuticle. These are composed of chiton and protein bound to form a complex glycoprotein. The exocuticle is absent at joints in the legs and along lines where the shell will rupture during molting. In the marine arthropods the procuticle includes salts and minerals. Where the epicuticle is not waxy and is thin, gases and water can pass into the animal’s body. The cuticle also has small pores that allow the release of compounds produced by glands within the animal. Not all of the cuticle is produced on the outside of the body. Some portions of it are produced around internal organs.
The colors of the crabs and other arthropods are produced by concentrations of brown, yellow, orange, and red melanin pigments within the cuticle. Iridescent greens, purples, and other colors are produced by striations of the epicuticle refracting light.
One disadvantage of the protective exoskeleton is the fact that it does not grow as fast as the interior soft tissue. They have solved this problem by periodic shedding, or molting, of the shell. Science calls this ecdysis, but we will continue to call it “molting”.
Step one is the detachment of the hypodermis from the skeleton. The hypodermis now secretes a new epicuticle. Step two, the hypodermis releases enzymes which pass through the new epicuticle and begin to erode the untanned endocuticle of the old skeleton. During this process the muscles and nerves are not affected and the animal can continue to move and feed. Step three, the old endocuticle is now completely digested. With the new procuticle produced by the hypodermis, the animal is now encased by both the old and new skeleton. Step four, the old skeleton now splits along predetermined lines, and the animal pulls out of the old skeleton. The new exoskeleton is soft – hence, the “soft-shelled blue crab” – and can be stretched to cover the increased size of the new animal. This stretching occurs due to tissue growth during steps 1-3, and from the uptake of air and water. The hardening of the new skeleton occurs due to the tanning of the new cuticle.
Stages between molts become longer as the animal grows older. Thus, there are numerous molts when the animal is young and as they age, they become fewer and farther between. Most insects have a finite number of molts they will go through. The marine arthropods seem to molt throughout their lives, though some species of crabs cease molting once they reach sexual maturity.
Molting is under hormonal control. Ecdyisone is secreted by certain endocrine glands, circulated through the blood stream, and acts directly on the epidermal cells. There are hormones that, if secreted, will inhibit the molting process. These are usually released if the animal senses trouble and that is not a good time.
During the period when the old shell is being digested many of the salts and minerals are absorbed by the tissue of the animal. Some people can eat crab but have allergic reactions when consuming soft shell crabs – most likely due to the increased salts and minerals in the tissue at this time. During step 3, many crustaceans will seek shelter and will remain there for a period of time after molting allowing the new shell to harden. The regeneration of lost limbs occurs during the molting process as well.
Molts of many species are hard to find because the “soft-shelled” animal can consume the molt to increase needed salts and minerals – or other marine animals may do so for the same reason. But horseshoe crab molts are pretty common and cool to collect. Another common molt found is that of the cicadids in the pine forest areas of our panhandle. The entire process is pretty amazing.
Reference
Barnes, R.D. 1980. Invertebrate Zoology. Saunders College Publishing. Philadelphia PA. pp. 1089.
In the diving world there are basically three forms of diving: free diving, compressed air diving, and 1-Atmosphere diving. After the recent accident with the OceanGate Titian we thought we would give some basics as to how this form of diving works. Let’s look at all three.
Free Diving
Free diving is just that… free of any diving apparatus. It is just you and the ocean. Frequently called “snorkeling” these days, the diver dons a mask (and at times snorkel), holds their breath and descends as deep and long as they can. Most sport free divers enjoy viewing the bottom in waters less than 10 feet deep. Through practice and training, others can go deeper. Some have dived as deep as 80 feet hunting fish using spearguns and have held their breath well over 2 minutes. There are of course the free diving championships where free divers descend by sleds to extreme depths under extreme pressure and ascend by air lift bags. This form of diving has not been of great use in science because the diver cannot go very deep and cannot stay very long. This makes behavior observations and data collecting difficult. Though it has been useful for shallow water surveys to do more “science” under the sea a different form of diving would be needed. One where you can go deeper and stay longer.
A free diver can explore 30-50 feet but for only a short period of time.
Photo: Molly O’Connor
Compressed Air Diving
Very early in science history they saw the need to develop some form of diving that would allow scientists to reach greater depths for longer periods of time. This meant taking the air with you. Dive bells made from crude materials were developed and tried as early as the 18th century. But most were very unreliable due to the materials used.
The concept of compressed air diving is that of using an air compressor to compress atmospheric air into a hose down to the diver. The diver would be able to regulate the air flow using a “regulator”. This concept was first used in what we now call hardhat diving. Divers wore heavy canvas suits with weighted boots and weight belts to reach the bottom. Air would be compressed using an air compressor on deck and fed to the diver using a tethered hose. The air would reach the diver within a brass helmet that had small view ports and a regulator on the back to regulate the air flow. Special care had to be taken to avoid getting exhaust from the air compressor into the air mix going to the diver, which could be toxic. There was also the threat of the air compressor running out of fuel and stopping the flow to the diver, who in their weighted apparatus could not reach the surface by swimming.
Another part of the problem was the pressure under which the diver is exposed. Standing on the surface of the earth you are under pressure. The atmosphere above is being pulled to the surface by the earth’s gravity and all objects are in its way. There is pressure from the air around you squeezing on your body at about 14.7 pounds for every square inch of your body (pounds per square inch – p.s.i.). We call this 1-Atmospheric pressure (14.7 p.s.i.). You do not feel this pressure because your body adjusts to it. However, when climbing a mountain, or flying a plane, there is less air above you and the atmospheric pressure decreases. We feel this in our ears (which helps adjust for pressure change) and feel the “equalization” of this pressure when we lightly blow our nose, or yawn – our ears “pop” and we do not feel the pressure any longer.
Water weighs more than air. As you descend into the ocean you feel the atmospheric pressure above the ocean surface AND the water pressure above you as well. The deeper you go, the greater the pressure. The rate of change is 14.7 psi every 33 feet (10 meters). At the surface we say we are at 1-Atmosphere (14 psi – 1-ATM). At 33 feet below the sea, you are at 2-ATMs (29.4 psi). At 66 feet you are at 3-ATMs (44.1 psi) and so on. Compressed air divers are exposed to this pressure as they descend and must equalize by “clearing” (lightly blow your nose while pinching it or yawning). Due to their sinus situation, some divers can clear more often than others and dive deeper. You do not dive with a head cold or other sinus problems, because you will not be able to clear. Even with good sinuses, there is a limit the human body can take. Most sport divers today dive to around 100 feet (4 ATMs – 58.8 psi). Some can/do dive to 200 feet (7 ATMs – 103 psi), but to dive deeper requires technical training and equipment. Technical divers need to be in good physical shape. Some professional technical divers have reached depths of 400 feet (13 ATMs – 191 psi). Below this is very hard on the human body. This is about the limit for compressed air diving.
But as Jacques Cousteau stated… “the problem is not so much going down… it’s coming back”.
What the famous ocean explorer meant by this was that the pressure on the diver not only squeezed your sinuses, but it also squeezed all of the gases in your tissues. The air you are breathing is about 78% nitrogen, 21% oxygen, and 1% trace gases. As you descend these gases are squeezed into your tissues and circulatory system. If you return too fast, these gases will expand in your tissues and cause what is called “the bends” (due to the fact your limbs begin to bend when it happens). It can be lethal and must be avoided. The deeper you go and the longer you stay, the more gas you squeeze into your system and the slower you must go to return to the surface to allow these gases to escape your system. Years ago, the U.S. Navy developed dive tables that told the diver how much time they had at a certain depth to safely return to the surface without stopping (non-decompression dives). Even though you could safely return without stopping, you were taught not to pass your bubbles as you ascended to make sure you were not coming up too fast. For example, a dive to 80 feet allowed you 30 minutes bottom time. You would descend, clearing your ears to adjust for the pressure change, make your dive watching time on your dive watch, and slowly ascend not passing your bubbles at, or before, the 30-minute time limit. Even once you were back on the surface there were still dissolved gases in your system and the table would let you know how long you had to sit to completely clear your system. Today, dive computers are used by divers to track this. They have alarms on them to let them know when it is time to ascend, and all divers now make a safety stop at 15 feet for five minutes JUST to make sure. Those who remain at 80 feet for longer than 30 minutes are considered “decompression divers” and the dive tables (dive computers) let you know at what depth you must stop (and for how long) to allow the dissolved gases to escape your system and safely return to the surface.
But the Bends were only one issue. Excessive amounts of nitrogen squeezed into your system could cause nitrogen narcosis during the dive. This gives the diver a “drunk” feeling, you begin to see things that are not there, your view of the sea bottom is inverted or flipped where the bottom is up and the water down. Just as driving drunk, this can be very dangerous. The diver is no longer alert and can make some fatal mistakes. And then there are embolisms. When you ascend the gases expand, if you are holding your breath the gases in your lungs will expand and may rupture the alveoli in your lungs. This is an embolism.
With hardhat diving you are tethered to the ship, you could only explore as far as your tether would allow you. In the 20th century they developed the Self-Contained Underwater Breathing Apparatus – SCUBA. A cylinder, originally made of steel and now aluminum, was filled with atmospheric air using an air compressor. This cylinder was strapped to the divers back and rigged with a two staged regulator that you could place in your mouth. The air was provided on demand by the diver. Today SCUBA diving is enjoyed by sportsman, adventurers, and scientists the world over. But the lessons mentioned above must be learned. No one should try SCUBA without attending a SCUBA certification course to learn how to do so safely.
Hardhat diving provides compressed air to the diver through a tethered hose, but limits their movement. SCUBA allows the compressed air diver more freedom over movement than hardhat diving.
Photo: NOAA
1-Atmosphere Diving
There is still a depth and time limit with compressed-air diving. Safe SCUBA is usually less than 200 feet, and you can explore as long as your air supply within the tank will allow you. Hardhat diving can supply more air, and increase time on the bottom, but there is still a depth limit and, as explained above, the longer you stay the more problems can occur for the diver. Those problems for the diver are due to the body being exposed to pressure (5-6 ATMs = 74-88 psi). IF the diver could remain at 1 ATM throughout the entire dive, then the Bends, Narcosis, and Embolisms would not be a concern. But how do you build a vessel where the inside pressure is 14.7 psi, and the outside is 100 psi? Could you build one that would keep the ocean from imploding it? And 100 psi is where compressed air divers can reach now. Could we build one that could reach 1000 feet (31 ATMs = 445 psi), or 10,000 feet (304 ATMs = 4454 psi). Imagine that… a vessel where the inside pressure is 14.7 psi and the outside environment is pushing in at 4454 psi!, could this be done?
Because we wanted to explore the deep sea, engineers began designing vessels for such a dive almost a century ago. Through design and testing, they learned quickly that a sphere was the best shape to use. With no corners, there are spaces for the external pressure to “grab” and either push or pull. You would want to use the strongest material available, and at that time it was steel. So, a steel sphere might do the trick. There was the issue of a window, or view port. If you had a steel sphere that could hold up to great pressure, could you put a window in it? If not, what is the point of going? Science developed an acrylic plastic (Plexiglas) that would bend some. Engineers discovered that cutting this acrylic glass window into a shape of a cone would absorb more pressure and allow the vessel to descend deeper allowing the 1-ATM divers to see outside. One window had an internal light that could illuminate the ocean outside so they could see.
Testing of such a vessel began in the early 20th century. The first dives came with a vessel called the bathysphere. This was designed by engineer Otis Barton and operated by himself and marine scientist Dr. William Beebe. The sphere was about five feet in diameter, 1 inch steel walls, and two viewing ports filled with crushed quartz glass (no acrylic glass yet). It would be lowered by a cable that also included a phone line for communication. Air was provided by cylinders within the vessel and there were absorbent materials to collect the expelled CO2. Air was moved around via a fan. The vessel was tested many times at varying depths before they allowed divers on board. The first dives were to depths of about 500 feet (16 ATMs = 223 psi), but they eventually reached a depth of 3000 feet (91 ATMs = 1336 psi). There were several issues during the course of these dives. Early on, the cables would become twisted, and they had to develop a method to keep this from happening. On one dive, water began leaking in after only going a few feet down. Once back on deck it was discovered one of the brass bolts that held the hatch shut was not tightened properly (showing the importance of COMPLETE review of the vessel before descending). The most catastrophic incident came during a test dive. There were initially three viewing ports on the bathysphere, and one had been covered with a steel plug. Dr. Beebe wanted to switch out the steel plug for another crushed quartz glass window so that he could do a video of a dive. They did, and during the test dive (to several hundred feet with no humans onboard) the new quartz window filled with water upon return. Dr. Beebe himself decided to unbolt the door. The intense pressure of water (due to the leak at depth) shot the brass bolt across the deck of the support ship like a bullet, then came the explosion of water that shot all the way across the deck to the crane that lowered the bathysphere. Reaffirming the dangers to this form of diving and the need for safety and detailed inspection of all equipment. Unmanned testing was a must for any new innovation tried on the system.
Using this sphere design the Trieste was designed by Swiss engineer Auguste Piccard. The goal of this vessel was to reach the very bottom of the ocean – the Challenger Deep at the bottom of the Marianna’s Trench – 36,000 feet = 1090 ATMs = 16,036 psi. This 1-ATM vessel would have an internal pressure of 15 psi and an external pressure of 16,000 psi. Obviously great care, thought, designing, and testing had to be done to pull this off. The sphere was steel, five inches thick, and had a diameter of seven feet. Unlike the bathysphere Dr. Beebe dove in, the Trieste was unthethered, so called a bathyscaphe. It operated like a hot air balloon. A large hull was attached above the sphere filled with gasoline (less dense than seawater and would float like hot air balloon). To sink, portions of the vessel would fill with seawater and there were conical cylinders filled with iron pellets (which would be released so the vessel would float back to the surface, just as bags of sand are dropped to allow the hot air balloon to rise). The view ports did use acrylic glass.
The dive took place in 1960. It took about four hours to reach the bottom. At 30,000 feet one of the exterior acrylic glass windows did crack but it did not impact the sphere nor the crew and the dive continued. They were on the bottom for about 20 minutes and were able to observe living organisms at the deepest part of our ocean. The pellets were dropped, and the ascent took about three hours. It was a marvel of engineering.
In the latter half of the 20th century the material for the spheres switched from steel to titanium. Electric motors were added so the pilot could literally drive around on the ocean floor. After speaking with a submersible pilot, he told me it was like driving a golf cart. An array of sampling equipment (buckets, vacuums, mechanical claws, etc.) were added to these vessels in order to collect from the seafloor. Many are outfitted with video cameras, and many have cameras that automatically photograph every so many minutes. The business of 1-ATM diving has vastly improved. One new design owned by the Harbor Branch Oceanographic Institute in Florida has a sphere made of the acrylic glass material. It is five inches thick, and your view is almost 360o. However, due to the material of the sphere being less than titanium, it has been certified to depths of no more than 3000 feet (92 ATMs = 1336 psi).
One of the more famous deep-sea submersibles is Alvin. Built in the 1960s, it has made more than 4000 dives to the deepest parts of the ocean, including the Titanic. It has been certified to depths up to 21,000 feet (637 ATMs = 9354 psi). It has discovered deep-sea hydrothermal vents, viewed deep ocean rift valleys, as well as videoed numerous deep-sea creatures. It has truly expanded marine science.
The Johnson Sea Link submersible The Johnson Sea Link submersible.
When the recent accident involving the submersible Titan occurred, I was camping out west in an area with no service. I did not hear about it until it was basically over. I did not get a lot of questions about I from the public but was interested in what went wrong. I did some reading and found the following.
Titan was owned and operated by a company called OceanGate based in the state of Washington.
OceanGate developed two submersibles – Cyclops 1 and Cyclops 2. Cyclops 2’s name was changed to Titan.
The vessel had a pressure hull made of titanium but was using reinforcement bars made from carbon fiber instead of steel.
The company stated that the pressure hull had been tested by the Applied Physics Lab at the University of Washington. It was approved for 4285 psi. That is 3000 meters, 9800 feet, 298 ATMs.
The Titanic sits at 12,500 feet, 3676 meters, 380 ATMs, 5568 psi.
It made several dives to the Titanic in 2021 and 2022. No incidents. A reporter who made one of those dives stated that they had to sign a waiver that stated they understood it was an experimental vessel.
The CEO was quoted several times stating “safety impedes innovation”.
There were emails from engineers prior to the first dive to Titanic that it was not safe to do so in this vessel. One billionaire from the west coast was offered a trip down but declined because of the safety issue.
Looking over the remains of Titan that reached the surface, one engineer stated that the implosion may have been due to the use of carbon fibers, or, an issue with one of the viewing ports. They were not sure. More reivew was needed.
As with so many airplane, shuttle, and ship accidents, the debris from the wreck will be examined more thoroughly and we will have a report of the most probable cause of the implosion.
It was a horrible accident, and we feel for the families of those lost during this dive. The statement about safety certainly catches our attention. This was a dive to 12,500 feet. Safety should have been a priority. The same can be said for any machine we use. I drive a camper van out west, several thousands of miles. We did, and should, make sure the vehicle was prepared for this. I have a safety check list for our camper before we pull it for miles. We should do the same for our cars. Many of you jump in your boats and head miles out into the Gulf of Mexico for a day of fishing. Do not neglect a safety check of your vessel before leaving. We know SCUBA divers check their gear before they dive, we know that airlines check their planes, we know the US Navy will not let a Blue Angel leave the ground unless it has passed a safety check. I have had friends who have dived on the Johnson Sea Links and Alvin. They have told me the crew goes over the vessel several times the night before a dive to make sure all is good, and the ship is ready. As a dive buddy of mine who served as a US Navy SEAL told me once – “Take care of your equipment… and your equipment will take care of you.” This is good advice for everyone.
“I can’t do what? – because of a mouse? – it’s only a mouse.”
This was a comment made by many who lived on Perdido Key when a small beach mouse found only there was added to the endangered species list. It is a comment heard often when many species are listed. A major reason most species begin to decline and become endangered is loss of habitat. We enter and change the habitat to suit our needs. Much of this includes construction of buildings and altering landscapes to a more artificial setting and much of the local wildlife is lost. So is the case with this little mouse.
The Choctawhatchee Beach Mouse is one of four Florida Panhandle Species classified as endangered or threatened. Beach mice provide important ecological roles promoting the health of our coastal dunes and beaches. Photo provided by Jeff Tabbert
The Perdido Key beach mouse (Peromyscus polionotus trissyllepsis) is one of seven subspecies of beach mice found in Florida, five of those found in the Florida panhandle. Beach mice are a subspecies of the Old-Field mouse (Peromyscus polionotus). They are small, about 5 inches long, with tails that have hair (which are an additional 2 inches). Beach mice typically have a brown/gray color on top and a lighter white underbelly allowing them to blend into their environment very well. The difference between the subspecies is the extent of the coloration.
The subspecies status, and genetic isolation, is part of the reason these mice are listed. Members of a population who are genetically isolated from others can undergo a process called speciation where the genetic changes that occur in one isolated group cannot/do not flow through the gene pool of the other isolated group. Over time, the genetics, and morphology, of one isolated group becomes different enough that a new subspecies, or even species, develops. This is the case with the Perdido Key beach mouse. It is isolated on Perdido Key, a barrier island, and does not interbreed with their closest neighbors – the Alabama beach mouse (P.p. ammobates) and the Santa Rosa beach mouse (P.p. leucocephalus). Because of this, ALL of the Perdido Key beach mice in the world live on Perdido Key. Their population is small and vulnerable.
These mice are dune dwellers living in small burrows. They prefer the primary dunes (closest to the Gulf) which are dominated by the grasses whose seeds they like to feed on. They forage at night (nocturnal) feeding on the seeds of the sea oat (Uniola paniculate), panic grass (Panicum amarum), and blue stem (Schizachrium maritimum) usually in the secondary dunes. Highly vegetated swales (low wet areas between the primary and secondary dunes) are used to move between these habitats, and they are also found in the tertiary dunes (on the backside of the island where trees can be found) where their burrows are more protected from storm surge during hurricanes. During periods when seeds are not available, beach mice will turn to small invertebrates to support their diet. Their foraging range averages around 50,000 ft2.
Breeding takes place in the winter, though can occur anytime of year if enough food is available. They are monogamous (males pairing with only one female for life) with the females giving birth after 23 days to four pups. New members of the family can move up to half a mile in search of a foraging range for themselves. It is understood that with limited available habitat on an isolated island, the carry capacity of the beach mouse would be low. Owls and snakes are some of the predators they face, but the beach mice have evolved to deal with few predator issues.
The increase of humans onto the barrier islands has negatively impacted them. The leveling of dunes for houses, condos, swimming pools, and shopping centers has significantly reduced suitable habitat for them as well as reduced the seed food source. Introduced feral and free roaming domestic cats have also been a large problem. Bridges connecting these islands to the mainland have allowed foxes and coyotes to reach, and increase pressure on, them. With these increased pressures, and small populations, these mice are now listed under the Endangered Species Act.
Conservation measures have included, predator control, building and landscaping restrictions, translocation (moving mice from large populations to those that are smaller), and reintroduction (releasing mice into areas where they once existed but no longer do). There has been success with the Choctawhatchee beach mouse in the Grayton Beach area, as well as the Perdido Key beach mouse in Gulf Islands National Seashore. Things that beach residents can do to help beach mice populations include keeping your pets inside at night, plant native grasses in your landscape, reduce night lighting, do not walk over dunes – use the cross walks.
Things seem to be improving for beach mice, but the development pressure is still there. Hopefully we will have these creatures as part of our panhandle barrier island communities for many years to come.
References
Beach Mouse Fun Facts. Gulf Islands National Seashore. U.S. Department of Interior.
