by Sheila Dunning | Oct 16, 2020
That’s the question from a recent group exploring what washed up on the beach after Hurricane Sally.
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.
by Sheila Dunning | Jul 16, 2020
Credits: Clemson University, www.insectimages.org
The hickory horned devil is a blue-green colored caterpillar, about the size of a large hot dog, covered in long black thorns. They are often seen feeding on the leaves of deciduous forest trees, such as hickory, pecan, sweetgum, sumac and persimmon. For about 35 days, the hickory horned devil continuously eats, getting bigger and bigger every day. In late July to mid-August, they crawl down to the ground to search for a suitable location to burrow into the soil for pupation. While the hickory horned devil is fierce-looking, they are completely harmless. If you see one wandering through the grass or across the pavement, help it out by moving it to an open soil surface.
The pupa will overwinter until next May to early-June, at which time, they completely metamorphosize into a regal moth (Citheronia regalis). Like most other moths, it is nocturnal. But, this is a very large gray-green moth with orange wings, measuring up to 6 inches in width. It lives only about one week and never get to eat. In fact, they don’t even have a functional mouth. Adults mate during the second evening after emergence from the ground and begin laying eggs on tree leaves at dusk of the third evening. The adult moth dies of exhaustion. Eggs hatch in six to 10 days.
Adult regal moth, Citheronia regalis (Fabricius).Credits: Donald W. Hall, UF/IFAS
The regal moth, and its larvae stage called the hickory horned devil, is native to the southeastern United States. The damage they do to trees in minimal. Learning to appreciate this “odd” creature is something we can all do. For more information: https://edis.ifas.ufl.edu/pdffiles/IN/IN20900.pdf
by Rick O'Connor | May 27, 2020
As we continue our series on marine life in the Gulf of Mexico, we also continue our articles on marine worms. Worms are not the most charismatic creatures in the Gulf, but they are very common and play a large role on how life functions in this environment. Roundworms are VERY common. There are at least three phyla of them but here we will focus on one – the nematodes.
A common nematode.
Photo: University of Florida
Most nematodes are microscopic, a large one would be about 2 inches, and some beach samples have found as many as 2 million worms in 10 ft2 of sand. So, what do we know about them? What role, or function, do they play in the ecology of the Gulf of Mexico?
Well first, they are long and round – cylinder shaped. There is a head end, but it is hard to tell which end is the head. Round is considered a step up from being flat in that it can allow for an internal body cavity. An internal body cavity can allow for the development of internal body organs. Internal body organs can move large amounts of nutrients, blood, oxygen, and hormones around the body allowing the animal to become larger. Some argue that a larger body can have advantages over smaller ones. Some say the opposite, but either way – a large body has been successful for some creatures and an internal body cavity is needed for this.
That said, the nematodes do not have a complete internal body cavity. So, they do not have a complete assortment of internal organs. Being round reduces your efficiency in absorbing enough needed nutrients, oxygen, etc. through your skin alone and this MAY be a reason they are small. They are very small.
There are free living and parasitic forms in this group. There are at least 10,000 species of them, and they can be found not only in the marine environment, but also in freshwater and in the soil found on land. They have played a role in the success of agriculture, infesting both crops and livestock. Nematodes can be a big concern for farmers and gardeners.
The free-living forms are known to be carnivorous, feeding on smaller microscopic creatures. They have toothed lips, and some have a sharp stylet to grab or stab their prey. Some stylets are hollow and can “suck” their prey in. Moving through the environment, they can consume algae, fungi, and diatoms. Some are deposit feeders and others are decomposers. On our farms and in our gardens, they are known to enter plants via the roots and can be found in the fruit.
The life cycle of the human hookworm.
Image: CDC
The parasitic version of nematodes has been a problem for some species. In humans we have the hookworms and pinworms. Dogs have their heart worms. An interesting twist on the parasitic nematode way of life, compared to flatworms like tapeworms, is their lack of a secondary (or intermediate host). The entire life cycle can take place in the same animal.
Females are larger than males and fertilizations is internal. Males are usually “hooked” at the tail end and hold on to the females during mating. About 50 eggs will be produced and released into the digestive tract, where they exit the animal in the feces and find new hosts either by the feces being consumed or drifting in the water column.
There multiple forms of parasitism in nematodes.
– Some are ectoparasites (outside of the body) on plants.
– Some are endoparasites in plants – some forming galls on the leaves.
– Some infest animals but only as juveniles.
– Some live-in plants as juveniles and animals as adults.
– Some live-in animals as juveniles and plants as adults.
It would be fair to say that many forms of marine creatures have nematodes living either within them, or on them. Some can be problematic and cause disease; some diseases can be quite serious. Others play an important role in “cleaning” the ocean, filtering the sand of organic debris. Many have heard of nematodes but know little about them. Either good or bad, they do play roles in the ecology of the Gulf of Mexico. 
by Carrie Stevenson | May 22, 2020
Sea pork comes in a wide variety of shapes and sizes. Photo credit: Carrie Stevenson, UF IFAS Extension
Recently I was walking the beach, enjoying a sunset and looking around at the shells and other oddities in the wrack line where waves deposit their floating treasures. Something bright green and oblong caught my eye. It was emerald in color, smooth yet fuzzy at the same time, and firm to the touch. At first, I thought it was a sea bean–a collective term for the many species of seeds and fruits that float to our shores from tropical locations in the Caribbean or Central/South America. The bright green definitely seemed like something botanical in nature. However, the vast majority of sea beans have a woody, protective shell similar to our more familiar pecans or acorns.
I remembered a family member asking about finding a mystery chunk of pink mass she found on the beach a few years ago. It resembled a pork chop more than anything else.
A different variety of sea pork that really lives up to its name. Photo credit: Stephanie Stevenson, Duval County Master Gardener
Looking closer and consulting a couple of resources, I realized we had both (most likely!) happened upon one of the oddest and often-questioned finds on our beaches: sea pork. Ranging in color from beige and pale pink to red or green, sea pork is a tunicate (or sea squirt), a member of the Phylum Chordata, home to all the vertebrate and semi-vertebrate animals. While they look and feel more like a cross between invertebrate slugs or sponges, the tunicates are more advanced organisms, possessing a primitive backbone in their larval “tadpole” form. Despite their blob-like appearance, they are more closely related to vertebrate animals than they are to corals or sponges.
The unusual life cycle of the tunicate. Photo credit: University of Washington, used with permission with Florida Master Naturalist program
During their short (just hours-long) larval stage, the tunicate larvae uses its nerve cord (supported by a notochord similar to a vertebrate spine) to communicate with a cerebral vesicle, which works like a brain. Similar to fish, this primitive brain uses an otolith to orient itself in the water, and an eyespot to detect light. These brain-like tools are utilized to locate an appropriate location to settle permanently. Using a sticky substance, the tunicate will attach its head directly to a hard surface (rocks, boats, docks, etc.) and go through a metamorphosis of sorts. The tunicate reabsorbs its tail and starts forming the shape and structure it needs for adulthood.
As an adult, the organism has a barrel shape covered by a tough tunic-like skin (hence “tunicate”). Adult bodies have two siphons, one to bring water in, another to shoot it out (giving them their other nickname, the sea squirt). The water passes through an atrium with organs that allow it to filter feed, trapping plankton and oxygen. The tunicates will spend most of their lives attached to a surface, pumping water in and out as filter feeders. They may be solitary or live in colonies, and vary widely in color and shape, lending variety to those chunks of sea pork found washing up.
I am still awaiting positive identification from an expert on my green find to confirm that it is, indeed, a tunicate and not an unfamiliar plant. Consulting with Extension colleagues, for now we are pretty confidently going with green sea pork. If you have seen one of these before or something resembling sea pork, let us know! It is fascinating to see the variety and unusual shapes and colors.
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by Carrie Stevenson | May 15, 2020
Crawfish boils are popular in the springtime. Crawfish are generally harvested from aquaculture operations. Photo credit: Libbie Johnson, UF IFAS Extension
“You get a line, I’ll get a pole, we’ll go down to the crawdad hole, honey, baby, mine“…there are lots of great zydeco songs singing the praises of crawfish (aka crayfish, crawdads, mudbugs). They are in season now, and while crawfish festivals all around the southeast are canceled due to concerns over COVID-19, they are still available and make for great eating. Most of us would recognize a cooked one alongside a feast of corn and potatoes, but would you know an actual crawfish hole if you came up on it?
Last fall, our office welcomed about 500 kids (over several days) to the 4-H camp in Barrineau Park for a field trip. I showed every single one of them a small muddy mound with an opening in the top, and asked if anyone could tell me what it was. Not a single kid knew! Now, I make sure I point crawfish mounds out to anyone I happen to be walking with, as they are fascinating little structures. Also referred to as crawfish chimneys due to their upright, open construction, they are built by a crawfish in a muddy area, often near a creek or other water source.
Crawfish mounds are constructed using small pellets of mud, and the opening connects down to a burrow. Photo credit: Carrie Stevenson, UF IFAS Extension
The industrious invertebrate uses its legs and mouth to create pellets of mud as it digs its burrow. It places mud up above the ground, using the mud balls like small bricks. Bricking up the entrance to its burrow (as opposed to placing discarded mud elsewhere) also protects a crawfish from exposure to predators on open soil. The crawfish chimneys can be 6 inches tall (or more!) and connect down to a burrow that may reach 3 feet deep, some straight down and others with side tunnels extending different directions.
Since the crawfish lives in wetland areas, it is theorized that these chimneys extending above the soil allow for better oxygen flow in the burrow. During a drought, crawfish will plug the opening of their mounds with mud, to keep water in the burrow from evaporating.
Crawfish in the wild are rarely harvested, although some folks do fish for them like the song referenced earlier. For the vast majority of crawfish harvested in commercial production, two species are the most popular–the white river crawfish (Procambarus zonangulus) and red swamp crawfish (Procambarus clarkii). They are typically farmed in coordination with rice, as both commodities thrive in flooded conditions. Most aquaculture operations are associated with Louisiana, but at least five other southern U.S. states farm crawfish. To learn more about this industry, check out LSU AgCenter’s informative video.
by Carrie Stevenson | Apr 30, 2020
White-topped pitcher plants in bloom at Tarkiln State Preserve. Photo credit: Carrie Stevenson, UF IFAS Extension
If you live in northwest Florida or southeast Alabama and have never laid eyes on our wild native carnivorous plants, it is about time! April and early May are the best time to see them in bloom. We have six species of pitcher plants (Sarracenia), the most common being the white-topped (Sarracenia leucophylla). However, they come in multiple colors, from yellow and red to a deep purple, and in different sizes.
Pitcher plants and their pinwheel-shaped flowers at Splinter Hill Bog. Photo credit: Carrie Stevenson, UF IFAS Extension
One thing they have in common, though—they eat meat. Carnivorous plants all over the world have evolved in places that left them few other options for survival. These plants are typically found in extremely wet, acidic, mucky soils with very low nutrient levels. Normally, plants uptake nutrients like nitrogen and phosphorus from the soil around them. Not being available in these particular environments, carnivorous plants (or more specifically, insectivorous) developed a way to extract nutrients from insects.
Small parrot pitcher plants lie on the ground instead of standing upright at Blackwater State Forest. Photo credit: Carrie Stevenson, UF IFAS Extension
So how does it work? Pitcher plants have a modified leaf, which instead of lying out flat like most plants, is rolled up into a tube, or “pitcher” shape. The inside of the pitcher has a sweet sap, and the walls of the tube are lined with tiny, downward-pointing hairs. Separate from the leaf, the plant has an elaborate flower structure, which attracts insects for pollination. While nearby, these insects are also attracted to the colorful leaf and the sweet sap in its pitcher. The insect will land on the lip of the leaf, then crawl down.
Those sticky, downward facing hairs are a trap, preventing insects from leaving the pitcher. Enzymes—a cocktail of proteins naturally found in many other plants but used creatively here—in the sap break down the bug bodies and convert them to nutrients for the plant. In fact, if you slice a cross-section into a pitcher wall or break open a dried one, you will see countless dried exoskeletons at the bottom of the tube. Several other enterprising species have taken advantage of the pitcher plant’s creative structure. More than once, I have seen tiny spiders spin webs across the mouth of the tube, or small lizards and frogs at the bottom, waiting patiently for prey.
Some of the best places to see pitcher plants in the area—they also bloom in October—are Tarkiln Bayou State Preserve, Weeks Bay National Estuarine Research Reserve, Splinter Hill Bog Preserve, and Blackwater State Forest.
