Sargassum

Sargassum

Sargassum washed ashore after a storm on Pensacola Beach. Photo credit: Carrie Stevenson, UF IFAS Extension

I am sure it drives the tourists a little crazy. After daydreaming all year of a week relaxing at the beach, they arrive and find the shores covered in leggy brown seaweed for long stretches. It floats in the shallow water, tickling legs and causing a mild panic—was that a fish? A jellyfish? A shark? Then, of course, high tide washes the seaweed up and strands it at the wrack line, shattering the vision of dreamy white sand beaches.

But for those visitors—and locals—willing to take a closer look, the brown algae known as sargassum is one of the most fascinating organisms in the sea. The next time you are at the beach, pick some up and turn it over in your hands. Sargassum is characterized by its bushy, highly branched stems with numerous leafy blades and berry-like, gas-filled structures. The tiny air sacs serve as flotation devices to keep the algae from sinking. This unique adaptation allows it to fulfill a niche at the top of the water column, instead of growing at the bottom or on another organism.

The sargassum fish blends incredibly well into its home within sargassum mats. It uses handlike pectoral fins to move around. Photo credit: Reef Builders

Sargassum tends to accumulate into large mats that drift through the water in response to wind and currents.  These drifting mats create a pelagic habitat that attracts up to 70 species of marine animals.  Several of these organisms are adapted specifically to life within the sargassum, reaching full growth at miniature sizes and camouflaged in shape, pattern, and color to blend in.  These very specialized fauna include the sargassum crab, the sargassum shrimp, sargassum flatworm, sargassum nudibranch, sargassum anemone, and the sargassum fish! The sargassum fish (Histrio histrio) is in the toadfish family, a group of slow-moving reef fish that pick their way through coral and algae by using their pectoral fins like hands. Sea turtle hatchlings will spend their early years feeding and resting within the relative safety of large mid-ocean sargassum mats.

The small air-filled sacs of sargassum allow it to float on the surface, becoming the basis of a teeming ecosystem. Photo credit: Carrie Stevenson, UF IFAS Extension

Over time the air sacs  lose buoyancy and the sargassum sinks, providing an important source of food for bottom-dwelling creatures.  If washed ashore, many of the animals abandon the sargassum or risk drying out and dying.

In general, most of the larger, familiar seaweeds like sargassum are brown algae.  Brown algae (including kelp and rockweed) have colors ranging from brown to brownish yellow-green.  These darker colors result from the brown pigment fucoxanthin, which masks the green color of chlorophyll.  Extractions from brown algae are commonly used in lotions and even heartburn medication!

Meadow Beauty

Meadow Beauty

Photo by: Sheila Dunning

Have you noticed the beautiful pink flowers in the meadows near the woods?  That’s what many early explorers of Florida may have said, which lead to the common name of Rhexia spp.  Meadow beauty (Rhexia spp.) is a Florida native found in mainly moist habitats, including flatwoods, wet meadows, marshes and savannas.  Rhexia species are herbaceous perennials that flowers from late spring to fall, going dormant in winter.  The simple leaves are simple and oppositely arranged.  The flower has four petals, four sepals and eight long, bright orange-yellow stamen with curving anthers on the end.  The light pink flowers face outward on a 1-2 feet tall stack, each one measuring about an inch across.  The unique shape of the stamen and anthers suggests that the Rhexia species are buzz pollinated.

By Bob Peterson from North Palm Beach, Florida, Planet Earth! – Buzz Pollination (Sonication), CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=38199019

Buzz pollination or sonication is a technique used by some bees to release pollen which is firmly held by the anthers. The anthers of buzz-pollinated plant species are typically tubular, with an opening at only one end, and the pollen inside is smooth-grained and firmly attached. In order to release the pollen, the bees grab onto the flower and move their flight muscles rapidly, causing the flower and anthers to vibrate, dislodging pollen. Honeybees cannot perform buzz pollination.   Only about 9% of the flowers in the world are primarily pollinated using buzz pollination.  So, meadow beauty is not just pretty, it has a unique connection with native bees.

Photo by: Sheila Dunning

Meadow beauty grows in full sun or partial shade.  The plant can reproduce by seeds and underground rhizomes.  Rhexia spp. are also a tasty treat for deer as they graze in the meadow.  The flowers don’t last long and can’t handle being touched.  In Greek, Rhexia means “breaks”.  So, enjoy them as you walk through the woods, but leave them for the bees rather than picking them.

Sturgeon in the Florida Panhandle

Sturgeon in the Florida Panhandle

This is one strange, primitive, dinosaur-looking fish.  They have large scutes embedded in their skin that give them an armored look.  They are big – reaching 14 feet in length and 800 pounds (though the Gulf sturgeon does not reach the large size of their cousin the Atlantic sturgeon).  They resemble sharks with their heterocercal caudal fin and possess long whiskers (barbels) suggesting a benthic mode of feeding.

Sturgeon are large fish. The barbels (whiskers) are for finding prey buried in the sediment. Notice the raised ganoid scales of this ancient creature.
Photo: U.S. Fish and Wildlife Service.

Panhandle residents know them from their impressive leaps as they head upriver for spawning in the spring.  The loud splash from one of these leaps can be heard for a long distance and is a concern for boaters who may be zipping up and down one of the local rivers on a jet sky, or even a bass boat.  When in college, we asked one of the professors – “why do mullet jump?”.  He paused for a second and responded – “for the same reason manta rays jump”.  There was another longer pause.  Understanding what was going on we took the bait and asked – “okay… why do manta rays jump?” – “we don’t know”.  However, that was in 1980 and a lot has been learned since.  We know that not only do mullet and mantas leap, but baleen whales and sturgeon do as well.  It is believed that baleen whales leap to communicate during the breeding season.  Since sturgeon breed in panhandle rivers, it is believed that this is the reason they may do so.  Scientists have also found it helps adjust their swim bladders with internal gas making them more buoyant in the water.

 

Like salmon, sturgeon swim up rivers to breed and spawn in the spring.  Fertilization is external and the gray-black eggs are laid on the substrate at the bottom.  The newborn and adults spend the remaining spring in the rivers, and the adults do not feed at this time.  In summer all head for the estuaries where the adults begin feeding with a vengeance.  They feed on a variety of benthic invertebrates and prefer sections of the bay that are well oxygenated.  Sturgeon spend the summer and much of the fall in the bays until the temperatures begins to drop at which time they head into the open Gulf of Mexico.  The spring, they find their breeding rivers and the reproductive cycle begins again.  This is a long-lived fish, reaching up to 50 years in age.

 

As far as the biogeography of this species, it is an interesting one.  They have been around for about 200 million years.  This was about the time the whole “Pangea” movement was going on – Florida did not look like Florida then.  There was an opening between what is now the southeastern United States and the Florida peninsula.  The water moving through this was called the Georgia Seaway or the Suwannee Channel.  This allowed marine species to easily move from the Atlantic to the Gulf of Mexico.  It was believed the current in this seaway was significant enough to keep silt and clays from reaching what would be become peninsula Florida, which was probably a submerged region of islands at the time.

 

During those times the Atlantic sturgeon (Acipenser oxyrinchus) inhabited this region, using southeast rivers for breeding.  About 25 million years ago global land mass changes began a period of ice formation that encouraged sea level to drop and the peninsula portion of Florida was exposed – the Florida people know today.  However, this new peninsula isolated populations of sturgeon (and other fish at that time) from reaching each other.  As time moved on, different genetic changes occurred in both populations to produce offspring that varied from each other.  These external morphological changes were enough to let you know they were different, but genetically they are close enough to still breed.  In these situations, they have deemed “subspecies” of each other.  The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) and the Gulf sturgeon (Acipenser oxyrinchus desotoi).  It is the Gulf sturgeon we find along the panhandle.  This process of producing new subspecies and species due to population isolation over time is called speciation.

 

Another interesting trend is the original range of the Gulf sturgeon was from the Texas/Louisiana border to about Tampa Bay.  This suggest that the fish took advantage of numerous rivers for breeding but there was a barrier as you reach the tropics.  Whether that barrier was climatic (temperature) biological (food source) or something else I am not sure.  With the high concentration of sturgeon in the panhandle you might think they require the alluvial rivers of this region.  But sturgeon are as common in tannic rivers, such as the Suwannee and Yellow Rivers, as they are in those alluvial ones, such as the Escambia and Apalachicola.

 

Today, their range is even smaller.  They are now found only in the rivers between Louisiana/Mississippi border to the Suwannee River.  This range reduction is probably due to habitat alteration (much of it human induced – such as dams) and overharvesting (the eggs of the sturgeon are used for caviar).  Today all species and subspecies of sturgeon are protected by the endangered species act.

 

Because this is an ancient fish, the biogeographic story of the sturgeon is an interesting one and shows how speciation occurs over time with all life.  They are really cool fish and, if you have not seen one leap yet, I hope you get to.  It is pretty amazing.

 

 

References

 

Florida’s Geologic History, University of Florida IFAS, https://edis.ifas.ufl.edu/publication/UW208.

 

NOAA Species Directory, Gulf Sturgeon, https://www.fisheries.noaa.gov/species/gulf-sturgeon.

 

NOAA Species Directory, Atlantic Sturgeon, https://www.fisheries.noaa.gov/species/atlantic-sturgeon.

 

Sturgeon, Florida Fish and Wildlife Conservation Commission, https://myfwc.com/conservation/you-conserve/wildlife/sturgeon/#:~:text=When%20the%20ambient%20pressure%20changes,to%20communicate%20with%20other%20sturgeon..

The Mystery of the East Pass

The Mystery of the East Pass

I am a curious person by nature.  When I first moved to the Emerald Coast, I had many questions about the area.  For example, why do they call this the Emerald Coast?  To help answer my questions, I turned to the Destin History and Fishing Museum in Destin, FL. If you haven’t yet visited the museum, I highly recommend it for locals and visitors alike.

It was easy to see why they call this the Emerald Coast once one lays eyes on the beautiful emerald color water.  Other questions weren’t so easily explained.  For example, I wanted to know why the pass out of Destin Harbor is called the East Pass, when it is clearly on the west side of Choctawhatchee Bay?  In fact, in the early 1900’s, the only outlet from the Bay to the Gulf was about 1.5 miles east of where the current pass resides and was called Old Pass Channel.  In 1929, a storm sealed off Old Pass Channel and a heavy dose of spring rain raised Choctawhatchee Bay five feet.  The threat of flooding inspired four local fishermen to take matters into their own hands and they dug a small trench across Santa Rosa Island to let the water out of the Bay. By the next morning, the trench had significantly widened into the East Pass we have today, connecting Choctawhatchee Bay to the  Gulf of Mexico.

 

 

 

 

However, that still didn’t explain the East Pass moniker.  To explain, we need to look west.  Choctawhatchee Bay is connected to Pensacola Bay by the Santa Rosa Sound.  This narrow passageway is the space between the Santa Rosa Island, a barrier island, and the mainland.  In the early 1900’s, many of the goods and services traded between inhabitants in Okaloosa and Walton counties traveled on ships from Choctawhatchee Bay, through the Santa Rosa Sound, and over to Pensacola Bay, instead of going out into the Gulf.  The opening between the Sound and Pensacola Bay is the West Pass, and hence the opening between the Sound and Choctawhatchee Bay is the East Pass.  Another mystery solved.

If you are interested in knowing more about the history of this area, the Destin History and Fishing Museum is the place to go.

 

 

 

 

 

Citation: Morang, A. . A study of geological and hydraulic processes at East Pass, Destin, FL.  Accessed: https://apps.dtic.mil/dtic/tr/fulltext/u2/a253890.pdf

“Foundation for a Gator Nation”

Groundhog or Gopher?

Groundhog or Gopher?

Groundhog

Groundhog Day is celebrated every year on February 2, and in 2021, it falls on Tuesday. It’s a day when townsfolk in Punxsutawney, Pennsylvania, gather in Gobbler’s Knob to watch as an unsuspecting furry marmot is plucked from his burrow to predict the weather for the rest of the winter. If Phil does see his shadow (meaning the Sun is shining), winter will not end early, and we’ll have another 6 weeks left of it.  If Phil doesn’t see his shadow (cloudy) we’ll have an early spring.  Since Punxsutawney Phil first began prognosticating the weather back in 1887, he has predicted an early end to winter

only 18 times.  However, his accuracy rate is only 39%.  In the south, we call also defer to General Beauregard Lee in Atlanta, Georgia or Pardon Me Pete in Tampa, Florida.

But, what is a groundhog? Are gophers and groundhogs the same animal?  Despite their similar appearances and burrowing habits, groundhogs and gophers don’t have a whole lot in common—they don’t even belong to the same family. For example, gophers belong to the family Geomyidae, a group that includes pocket gophers, kangaroo rats, and pocket mice. Groundhogs, meanwhile, are members of the Sciuridae (meaning shadow-tail) family and belong to the genus Marmota. Marmots are diurnal ground squirrels. There are 15 species of marmot, and groundhogs are one of them.

Science aside, there are plenty of other visible differences between the two animals. Gophers, for example, have hairless tails, protruding yellow or brownish teeth, and fur-lined cheek pockets for storing food—all traits that make them different from groundhogs. The feet of gophers are often pink, while groundhogs have brown or black feet. And while the tiny gopher tends to weigh around two or so pounds, groundhogs can grow to around 13 pounds.

While both types of rodent eat mostly vegetation, gophers prefer roots and tubers while groundhogs like vegetation and fruits. This means that the former animals rarely emerge from their burrows, while the latter are more commonly seen out and about. In the spring, gophers make what is called eskers, or winding mounds of soil. The southeastern pocket gopher, Geomys pinetis, is also known as the sandy-mounder in Florida.

Southeastern Pocket Gopher

The southeastern pocket gopher is tan to gray-brown in color. The feet and naked tail are light colored. The southeastern pocket gopher requires deep, well-drained sandy soils. It is most abundant in longleaf pine/turkey oak sandhill habitats, but it is also found in coastal strand, sand pine scrub, and upland hammock habitats.

Gophers dig extensive tunnel systems and are rarely seen on the surface. The average tunnel length is 145 feet (44 m) and at least one tunnel was followed for 525 feet (159 m). The soil gophers remove while digging their tunnels is pushed to the surface to form the characteristic rows of sand mounds. Mound building seems to be more intense during the cooler months, especially spring and fall, and slower in the summer. In the spring, pocket gophers push up 1-3 mounds per day. Based on mound construction, gophers seem to be more active at night and around dusk and dawn, but they may be active at any time of day.

Pocket Gopher Mounds

Many amphibians and reptiles use pocket gopher mounds as homes, including Florida’s unique mole skinks. The pocket gopher tunnels themselves serve as habitat for many unique invertebrates found nowhere else.

So, groundhogs for guesses on the arrival of spring.  But, when the pocket gophers are making lots of mounds, spring is truly here.  Happy Groundhog’s Day.

Animal, Vegetable, or Mineral?

Animal, Vegetable, or Mineral?

That’s the question from a recent group exploring what washed up on the beach after Hurricane Sally.

long, round brownish invertebrate

Sea Cucumber
Photo by: Amy Leath

They have no eyes, nose or antenna.  Yet, they move with tiny little legs and have openings on each end.  Though scientists refer to them as sea cucumbers, they are obviously animals.  Sea cucumbers get their name because of their overall body shape, but they are not vegetables.

There are over 1,200 species of sea cucumbers, ranging in size from ¾“ to more than 6‘ long, living throughout the world’s ocean bottoms.  They are part of a larger animal group called echinoderms, which includes starfish, urchins and sand dollars. Echinoderms have five identical parts to their bodies.  In the case of sea cucumber, they have 5 elongated body segments separated by tiny bones running from the tube feet at the mouth to the opening of the anus.  These squishy invertebrates spend their entire life scavenging off the seafloor.  Those tiny legs are actually tube feet that surround their mouth, directing algae, aquatic invertebrates, and waste particles found in the sand into their digestive tract.  What goes in, must come out.  That’s where it becomes interesting.

Sea cucumbers breathe by dilating their anal sphincter to allow water into the rectum, where specialized organs referred to as respiratory trees (or butt lungs) extract the oxygen from the water before discharging it back into the sea.  Several commensal and symbiotic creatures (including a fish that lives in the anus, as well as crabs and shrimp on its skin) hang out on this end of the sea cucumber collecting any “leftovers”.

But, the ecosystem also benefits.  Not only is excess organic matter being removed from the seafloor, but the water environment is being enriched.  Sea cucumbers’ natural digestion process gives their feces a relatively high pH from the excretion of ammonia, protecting the water surrounding the sea cucumber habitats from ocean acidification and providing fertilizer that promotes coral growth.  Also, the tiny bones within the sea cucumber form from the excretion of calcium carbonate, which is the primary ingredient in coral formation. The living and dying of sea cucumbers aids in the survival of coral beds.

When disturbed, sea cucumbers can expose their bony hook-like structures through their skin, making them more pickle than cucumber in appearance.  Sea cucumbers can also use their digestive system to ward of predators.  To confuse or harm predators, the sea cucumber propels its toxic internal organs from its body in the direction of the attacker.  No worries though.  They can grow them back again.

Hurricane Sally washed the sea cucumbers ashore so you could learn more about the creatures on the ocean floor.  Continue to explore the Florida panhandle outdoor.