by Thomas Derbes II | Jun 21, 2024
In Part 1 of The Estuary’s Natural Filtration System article, we discussed the major contributors to natural filtration inside of the estuary. These examples included oysters, marsh plants, and seagrasses. In Part 2, we will discuss the smaller filter-feeding organisms including tunicates, barnacles, clams, and anemones.
Tunicates
Pleated Sea Squirt – Photo Credit: Don Levitan, PH.D. FSU
Tunicates, also known as sea squirts, are very interesting marine invertebrates and can be easily confused for a sponge. There are many different types of tunicates in the estuaries and can be either solitary or colonial. You might’ve seen these at an aquarium attached to different substrates, and when removed from the water, their name sea squirt comes into play. Tunicates have a defense mechanism to shoot out the water inside their body in hopes of being released by any predator.
Tunicates are filter feeders and intake water through their inhalant siphons and expel waste and filtered water through their exhalant siphons. Tunicates can filter out phytoplankton, algae, detritus, and other suspended nutrients. The tunicate produces a mucus that catches these nutrients as it passes through, and the mucus is then conveyed to the intestine where it is digested and absorbed.
An invader to the Gulf of Mexico, the Pleated Sea Squirt (Styela plicata), hitched rides on the hulls of ships and found the Gulf of Mexico waters very favorable. You can sometimes spot these organisms on ropes that have been submerged for a long period of time in salty waters. Even though they are non-native, these sea squirts can filter, on average, 19 gallons of water per day.
Barnacles
Barnacles along the seashore is a common site for many.
Photo: NOAA
One organism that seems ubiquitous worldwide is the barnacle (Genus Semibalanus and Genus Lepas). The Genus Semibalanus contains the common encrusting barnacle we are accustomed to seeing in our waterways along pilings, submerged rocks, and even other animals (turtles, whales, crabs, and oysters). The Genus Lepas contains Gooseneck Barnacles and can be seen attached to flotsam, floating organic debris, and other hard surfaces and have a stalk that attaches them to their substrate. Interesting fact, certain gooseneck barnacle species are eaten in different parts of the world.
This image from a textbook shows the internal structure of a barnacle. Notice the shrimplike animal on its back with extendable appendages (cirri) for feeding.
Image: Robert Barnes Invertebrate Zoology.
Barnacles have over 2,100 species, are closely related to crabs and lobsters, and are a part of the subphylum Crustacea. At first glance, you might not think a barnacle is closely related to crabs, but when you remove the hard plates surrounding it, the body looks very similar to a crab. Barnacles also have life cycle stages that are similar to crabs; the nauplius and cyprid developmental stages. Inside of the hard plates is an organism with large feather-like appendages called cirri. When covered by water, the barnacles will extend their cirri into the water and trap microscopic particles like detritus, algae, and zooplankton. Barnacles are at the mercy of tides and currents, which makes quantifying their filtering ability difficult.
Hard Clams
Clams of North Florida – UF/IFAS Shellfish
Even though not as abundant in the Florida Panhandle as they were in the 1970’s – 1980’s, hard clams (Mercenaria mercenaria and M. campechiensis) can still be found in the sand along the shoreline and near seagrass beds. These clams are also known as Quahogs and are in the family Veneridae, commonly known as the Venus clam family, and contain over 500 living species. Most of the clams in the family Veneridae are edible and Quahogs are the types of clams you would see in a clam chowder or clam bake.
Being the only bivalve on this list does not make it any less important than the oyster or scallop on Part 1’s list. In fact, a full-grown adult Southern Quahog clam can filter upwards of 20 gallons of water per day and have a lifespan of up to 30 years. Clams also live a much different lifestyle than their oyster and scallop cousins. Clams spend the majority of their life under the sand. Their movement under the sand helps aerate and mix the soil, which can sometimes stimulate seagrass growth.
Right outside the Florida Panhandle and in the Big Bend area, Quahog clams are commercially farmed in Cedar Key. Southern Quahog clams are also being used for restoration work in South Florida. Clams are being bred in a hatchery and their “seed” are being released into Sarasota Bay to help tackle the Red Tide (Karenia brevis) issue. According to the project’s website, they have added over 2 million clams since 2016, and the clams are filtering over 20 million gallons of seawater daily.
Anemones
Tube-Dwelling Anemone Under Dissection Scope – UF/IFAS Shellfish
Anemones are beautiful Cnidarians resembling an upside-down, attached jellyfish, which couldn’t be closer to the truth. The phylum Cnidaria contains over 11,000 species of aquatic animals including corals, hydroids, sea anemones, and, you guessed it, jellyfish. Anemones come in many different shapes and sizes, but the common estuary anemones include the tube-dwelling anemone (Ceriantheopsis americana) and the tricolor anemone (Calliactis tricolor), also known as the hitchhiking anemone. If you have ever owned a saltwater aquarium, you might have run into the pest anemone Aiptasia (Aiptasia sp.).
Anemones filter feed with their tentacles by catching plankton, detritus, and other nutrients as the tide and current flows. The tentacles of the anemone are lined with cnidocytes that contain small amounts of poison that will stun or paralyze the prey. The cnidae are triggered to release when an organism touches the tentacles. If the anemone is successful in immobilizing the prey, the anemone will guide the prey to their mouth with the tentacles. Just like the barnacle, anemones are at the mercy of the tides and currents, and filtration rates are hard to calculate. However, if you ever see an anemone with food around, they move those tentacles to and from their mouths quickly and constantly!
In Parting
As you can see, there are many different natural filters in our estuary. Healthy, efficiently filtering estuaries are very important for the local community and the quality of the waters we love and enjoy. For more information on our watersheds and estuaries and how to protect them, visit Sea Grant’s Guide To Estuary-Friendly Living.
by Thomas Derbes II | May 3, 2024
I might shock a few people when I say this, but I’d rather be out in the bay somewhere rather than the beach. I just feel like I always bring a gallon of sand back on me even after washing down before getting in the car. However, there is one activity that will always get me out on the beach, and it just so happens to be the right time of the year for it. Florida Pompano (Trachinotus carolinus), aka Pompa-Yes, have started to cruise the white, sandy beaches in search of food as they migrate west to their breeding grounds. While out on a fishing trip this past weekend, the Pompano (and every other fish) eluded me, but I was blessed with an amazing array of wildlife.
When I first arrived at my spot just to the east of Portofino Towers, I was greeted with a pair of Sanderlings (Calidris alba) playing the “water is lava” game while taking breaks between waves to argue with each other and probe the sand with their beaks from marine invertebrates. When I was doing more research on sanderlings, one comment I saw was that they ran like wind-up toys, and that’s the truth! They were pretty brave too, not a single footprint of mine in the wet sand didn’t go un-probed. Sanderlings are “extremely long-distance” migratory birds that breed on the arctic tundra close to the North Pole and winter on most of the sandy beaches in the Gulf of Mexico and around the world. Non-breeding sanderlings will often stay on sandy beaches throughout the summer to save energy. They were great entertainment for the whole fishing trip.
Sanderlings in the Tide Pool – Thomas Derbes II
Brown Pelicans (Pelecanus occidentalis) were out in numbers that day. I am not the best photographer, but I was very proud to capture a Pelican mid-flight. These birds are residents of the Florida Panhandle year-round. If you’ve ever been to Pensacola, you might have bumped into one of the many Pelican Statues around the area, and they’re pretty much the unofficial mascot of the area. I am always amazed at how these seemingly big, clumsy birds can effortlessly glide over the waves and water as if they are the Blue Angels doing a low-pass. Pelicans were almost wiped out by pesticide pollution in the 1960’s, but they have made an incredible comeback.
Brown Pelican – Thomas Derbes II
While I was waiting for a Pompano to bite, I had a visit from a small Atlantic Stingray (Dasyatis sabina) that was caught in the tidepool that was running along the beach. He didn’t seem injured or sick, so I quickly grabbed a glove and released him into the gulf. Stingrays are pretty incredible creatures and can get to massive sizes, but they do contain a large, venomous spine on their tail that poses a threat to beach goers. They are not aggressive however, and a simple remedy to make sure you don’t get hit is to do the “Stingray Shuffle” by shuffling your feet while you move in the water to scare up the stingrays.
Atlantic Stingray Cruising the Tide Pool- Thomas Derbes II
As I was getting ready to pack up, I noticed a new shorebird flying in to investigate the seaweed that had washed up on shore. I had a hard time identifying this bird, but once I was able to see it in flight with its white stripe down the back, I realized it was a Ruddy Turnstone (Arenaria interpres). Turnstones get their name from their foraging behavior of turning over stones and pebbles to find food. Even though we do not have pebbles, the turnstone was looking through the seaweed for any insects or crustaceans that might be an easy meal. Turnstones are also “extremely long-distance” migratory birds breeding in the arctic tundra with non-breeding populations typically staying on sandy beaches during the summer. The turnstone made sure to stay away from me, but I was able to get a good photo of it as it ran from seaweed clump to clump.
Ruddy Turnstone – Thomas Derbes II
While I didn’t catch anything to bring home for dinner, I did get to enjoy the beautiful day and playful wildlife that I wouldn’t have experienced sitting on a couch. You can turn any bad fishing day into an enjoyable day if you pay attention to the wildlife around you!
by Dana Stephens | May 3, 2024
Understanding Salinity in Northwest Florida’s Waters with a Family Activity
Dana Stephens, 4-H Agent
Salinity is the amount of total dissolved salts in water. This includes all salts not just sodium chloride, or table salt. Salinity is important in aquatic environments as many flora and fauna depend on salt and the level of dissolved salts in the water for survival. People interested in the composition of water frequently measure chemical and physical components of water. Salinity is one of the vital chemical components measured and often measured by a device determining how readily electrical conductance passes between two metal plates or electrodes. These units of electrical conductance, the estimate of total dissolved salts in water, is described in units of measurement of parts per thousand (PPT).
At the large scale, Earth processes, such as weathering of rocks, evaporation of ocean waters, and ice formation in the ocean, add salt to the aquatic environment. Earth processes, such as freshwater input from rivers, rain and snow precipitation, and ice melting, decrease the concentration of salt in the aquatic environment. Anthropogenic (human-induced) activities, such as urbanization or atmospheric deposition, can also contribute to changes in salinity.
Salinity and changes in salinity affect how water moves on Earth due to contrasts in the density of water. Water containing no dissolved salts is less dense than water containing dissolved salts. Density is weight per volume, so water with no dissolved salts (less dense) will float on top of water with dissolved salts (denser). This is why swimming in the ocean may feel easier than swimming in a lake because the denser water provides increased buoyancy.
Northwest Florida is a unique place because we have a variety of surface waters that range in salinity. There are ponds, lakes, streams, rivers, and springs, which have no to low salinity levels (0 to 0.5 PPT), and commonly referred to as freshwater systems. We house six estuaries—Perdido Bay, Pensacola/Escambia Bay, Choctawhatchee Bay, St. Andrews Bay, St. Joseph Bay, and Apalachicola Bay. Estuaries are bodies of water with freshwater input(s) (e.g., rivers) and a permanent opening to the ocean (e.g., Destin Pass in the Choctawhatchee Bay). Estuarine waters are termed brackish water (0.5 to 30 PPT) due to the dynamic changes in salinity at spatial and temporal scales. Waterbodies with an even more dynamic change in salinity are the coastal dune lakes Northwest Florida’s Walton and Bay Counties. Coastal dune lakes are waterbodies perched on sand dunes that intermittently open and close to the Gulf of Mexico. Sometimes these waterbodies are fresh and sometimes they have the same salinity as the Gulf of Mexico, like after a large storm event. Finally, the Gulf of Mexico, or ocean, has the highest salinity (> 30 PPT) among the waterbodies of Northwest Florida.
Here is an educational activity for the family to explore salinity and how salinity differs among Northwest Florida waters.
by Andrea Albertin | Apr 26, 2024
Green stormwater infrastructure at Cascades Park in Tallahassee, Florida. Image: T. Jones, UF/IFAS.
Join us for a two-part webinar series on Managing Stormwater in a Changing FL Panhandle on May 1, 2024 from 8:30-11:30 am CST (9:30-12:30 pm EST), and May 15, 2024 from 8:30-11:30 am CST (9:30-12:30 pm EST).
We are also offering two optional no-cost field tours of stormwater management sites in northwest Florida. The first will be held on May 3 in Pensacola to the Escambia County Central Office Complex, and the second on May 22 in Tallahassee to the Upper Lake Lafayette Nutrient Reduction Facility (aka Weems Pond). Detailed information as well as how to register for both the webinars and the field tours is found below.
Webinar series: Information and registration
Please register for the webinar series here: Eventbrite link Once in the registration site, you will have to register for both dates separately.
May 1: Day 1 will focus on Green Stormwater Infrastructure (GSI) and its maintenance, as well as presentations and discussion on the ecological function of GSI+LID.
May 15: Day 2 will focus on implementing GSI and LID at the community level, with presentations about ongoing research on extreme sea levels and effects on flooding events, a resiliency case study on Cedar Key and funding opportunities for GSI and LID through FDEP.
PDHs and CEUs offered:
- 4 Professional Development Hours (PDH) will be offered through the Florida Board of Professional Engineers. Two PDHs will be offered for Day 1 and two for Day 2.
- 4 Continuing Education Units (CEU) will be offered for Pesticide Applicators through FDACS in these categories: Ornamental & Turf, Private Applicator Ag, Right-of-Way, Aquatic, Natural Areas, Commercial Lawn & Ornamental, Limited Commercial Landscape Maintenance, Limited Lawn & Ornamental and Limited Urban Fertilizer.
The webinar is free for those not seeking PDHs or CEUs. For those seeking PDHs or CEUs, the cost is $50 for Day 1, and $50 for Day 2.
Field Tours: Information and registration
Please register for each tour separately through the Eventbrite links provided.
May 3 Pensacola Tour: Join us for a tour of the Escambia County Central Office Complex, a LEED Gold certified building with pervious pavement, energy efficient design, and the largest green roof in Florida. Registration: Pensacola Field Tour
May 22 Tallahassee Tour: Join us for a tour of the Upper Lake Lafayette Nutrient Reduction Facility (aka Weems Pond) which captures sediment and trash from a large upstream drainage basin and uses modern treatment methods to filter the stormwater before it enters a natural system. The tour will be led by the City of Tallahassee Stormwater Planning team. Registration: Tallahassee Field Tour
We look forward to your attendance! Please contact Andrea Albertin if you have any questions at (850) 875-7111 or via email: albertin@ufl.edu
by Rick O'Connor | Apr 20, 2024
The Snake Watch Project is one that is helping residents in the Pensacola Bay area better understand which species of snakes are most encountered, where they are encountered, and what time of year. The project began in 2022 and over the last two years between 50-60% of the 40 species/subspecies of snakes known in the Pensacola Bay area have been encountered. The majority of these encounters have been in the spring, with garter snakes, black racers, banded water snakes and cottonmouths being the most common.
The eastern garter snake is one of the few who are active during the cold months.
Photo: Molly O’Connor
The 1st quarter reports cover the winter months, and you would expect fewer encounters – but encounters do happen. In 2022 there were only 6 encounters during the winter months. There was one mid-sized snake (between 12-24” maximum length), 2 large snakes (greater than 3’ maximum length), 1 water snake and 2 cottonmouths for a total of five species. In 2023 there was a significant increase in 1st quarter reports. There were 57 encounters (26% of the total for the year) and 13 species logged.
- Two species of small snakes (less than 12” maximum length) were encountered three times.
- Three species of mid-sized snakes were encountered nine times, this included an encounter with the eastern hognose snake.
- Six species of large snakes were encountered 17 times. These include the rarely seen eastern kingsnake and Florida pine snake.
- Three species of water snakes were encountered, including the green water snake.
- The cottonmouth was encountered 10 times during the 1st quarter of 2023.
This increase in sightings may be more a result of more people interested in the project than a true increase in snake activity, but it does provide us with information on snake activity during the winter months. Eastern garter snakes, eastern ribbon snakes, banded water snakes, and cottonmouths were the most frequently encountered.
A cottonmouth found on the trail near Ft. Pickens.
Photo: Ricky Stackhouse
Snake encounters during the 1st Quarter of 2024 are down. This year 27 encounters occurred logging eight species. The cottonmouth continues to be the most encountered snake in our area and the only one who was encountered in double digits (n=11). Other species encountered included the eastern garter snake, eastern ribbon snake, gray rat snake, corn snake, southern black racer (encountered every month), eastern coachwhip, banded water snake (encountered every month), and the cottonmouth (also encountered each month this quarter).
We will continue to log encounters during the spring. If you see a snake, please let Rick O’Connor know at roc1@ufl.edu.
by Rick O'Connor | Mar 30, 2024
I was having dinner with my family on a cool March evening when one said “I have not seen any Swallow-tailed Kites yet. We usually see them this time of year”. To which I replied, “I saw one today!” – and I had. It was March 23, a very windy afternoon, and I saw it briefly zip over our backyard. The Swallow-tailed Kites were back.
Back in the sense they were back from their long migration from South America. The Swallow-tailed Kite resides there and ventures north to Central and North America during the summer for the breeding season.
The Swallow-tailed Kite.
Photo: Cornell University
It is a magnificent bird, described as “one of the most awesome birds in the U.S.”. Their long slender bodies are sharp in contrast with a brilliant white head and a deep black body. They have long pointed wings which they use to soar with grace, rarely flapping their wings, and their key feature of the scissor-looking forked tail. They are a relatively large bird somewhere between the size of a crow and a large goose. Swallow-tailed kites are often seen soaring just above the treetops searching for food but can also be seen at higher elevations gliding along with the wind. It is a bird that many get excited about when they see it.
Arriving in the United States in late February and March, they seek out opportunities for nesting habitat. Their preference are tall trees, usually 60 feet or taller, and most often select pine trees, though have been known to nest in cypress and other large trees. They usually select trees close to water or open fields. These locations provide an abundance of their favorite prey – insects. They can be seen zooming close to the trees to grab unwary prey and will, at times, take larger creatures like treefrogs, lizards, and small snakes. Their beaks are small however, and so prey selection is limited.
Both the males and females participate in nest building. Swallow-tailed kites are monogamous and mate pairing often occurs during the migration. They usually build a new nest each season but often is the same location. Males are territorial of these nest locations and defend them with local vocalizations. Despite this, many swallow-tailed kite nests can be found near each other.
The Swallow-tailed Kite.
Photo: Rodney Cammauf – National Park Photo.
Once the young hatch, the female remains with them while the male forages for food. He typically brings it back to the nest in his talons, perches and transfers the food to his beak, and the provides it to the female who in turn feeds the chicks. After fledging, around August or September, it is time to head back to South America and they leave our area until next spring.
Swallow-tailed kites were once common all along the Mississippi River drainage as far north as Minnesota. However, the numbers declined significantly, primarily due to humans shooting them, and today they are only found in the lower coastal regions of the southeastern U.S. Today they can be found, but are uncommon, in coastal Louisiana, Mississippi, Alabama, Georgia, and South Caroline. In Florida they are considered uncommon in the panhandle but common in the peninsula part of the state. Their numbers seem to be increasing but the loss of tall nesting trees is a major issue today. The clearing of these tall trees due to agriculture and urban development have kept them from reestablishing their original range. But for now – the swallow-tailed kites are back.
For more information on this amazing bird read the following.
Swallow-tailed Kite. All About Birds. Cornell Lab. Cornell University.
https://www.allaboutbirds.org/guide/Swallow-tailed_Kite/id.
Swallow-tailed Kite. Bird Guide – Hawks and Eagles. Audubon Society. https://www.audubon.org/field-guide/bird/swallow-tailed-kite.
