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 Ray Bodrey | Jun 3, 2024
The University of Florida/IFAS Extension & Florida Sea Grant faculty are reintroducing their acclaimed “Panhandle Outdoors LIVE!” series on St. Joseph Bay. This ecosystem is home to some of the richest concentrations of flora and fauna on the Northern Gulf Coast. This area supports an amazing diversity of fish, aquatic invertebrates, turtles and other species of the marsh and pine flatwoods. Come learn about the important roles of ecosystem!
Registration fee is $40. You must pre-register to attend.
Registration link: https://www.eventbrite.com/e/panhandle-outdoors-live-st-joseph-bay-by-land-sea-tickets-906983109897
or use the QR code:
Meals: Lunch, drinks & snacks provided (you may bring your own)
Attire: outdoor wear, water shoes, bug spray and sunscreen
*If afternoon rain is in forecast, outdoor activities may be switched to the morning schedule
Held at the St. Joseph Bay State Buffer Preserve Lodge: 3915 State Road 30-A, Port St. Joe
| 8:30 – 8:35 Welcome & Introduction – Ray Bodrey, Gulf County Extension (5 min) |
| 8:35 – 9:20 Diamondback Terrapin Ecology – Rick O’Connor, Escambia County Extension |
| 9:20 – 10:05 Exploring Snakes, Lizards & the Cuban Tree Frog – Erik Lovestrand, Franklin County Extension |
| 10:05 – 10:15 Break |
| 10:15 – 11:00 The Bay Scallop & Habitat – Ray Bodrey, Gulf County Extension |
| 11:00 – 11:45 The Hard Structures: Artificial Reefs & Derelict Vessel Program – Scott Jackson, Bay County Extension |
| 11:45 – Noon Question & Answer Session – All Agents |
| Noon – 1:00 Pizza & Salad! |
| 1:00 – 1:20 Introduction to the Buffer & History – Buffer Preserve Staff |
| 1:20 – 2:20 Tram Tour – Buffer Preserve Staff |
| 2:20 – 2:30 Break |
| 2:30 – 3:00 A Walk in the Mangroves – All Agents |
| 3:00 – 3:15 Wrap up & Adjourn – All |
by Carrie Stevenson | May 24, 2024
This tree was downed during Hurricane Michael, which made a late-season (October) landfall as a Category 5 hurricane. Photo credit: Carrie Stevenson, UF IFAS Extension
There are a lot of jokes out there about the four seasons in Florida—instead of spring, summer, fall, and winter; we have tourist, mosquito, hurricane, and football seasons. The weather and change in seasons are definitely different in a mostly-subtropical state, although we in north Florida do get our share of cold weather (particularly in January!).
All jokes aside, hurricane season is a real issue in our state. With the official season about to begin (June 1) and running through November 30, hurricanes in the Gulf-Atlantic region are a legitimate concern for fully half the calendar year. According to records kept since the 1850’s, our lovely state has been hit with more than 120 hurricanes, double that of the closest high-frequency target, Texas. Hurricanes can affect areas more than 50 miles inland, meaning there is essentially no place to hide in our long, skinny, peninsular state.
A disaster supply kit contains everything your family might need to survive without power and water for several days. Photo credit: Weather Underground
I point all these things out not to cause anxiety, but to remind readers (and especially new Florida residents) that is it imperative to be prepared for hurricane season. Just like picking up pens, notebooks, and new clothes at the start of the school year, it’s important to prepare for hurricane season by firing up (or purchasing) a generator, creating a disaster kit, and making an evacuation plan.
A summary infographic showing hurricane season probability and numbers of named storms predicted from NOAA’s 2024 Atlantic Hurricane Season Outlook. (Spanish version) (Image credit: NOAA)
Peak season for hurricanes is September. Particularly for those in the far western Panhandle, September 16 seems to be our target—Hurricane Ivan hit us on that date in 2004, and Sally made landfall exactly 16 years later, in 2020. But if the season starts in June, why is September so intense? By late August, the Gulf and Atlantic waters have been absorbing summer temperatures for 3 months. The water is as warm as it will be all year, as ambient air temperatures hit their peak. This warm water is hurricane fuel—it is a source of heat energy that generates power for the storm. Tropical storms will form early and late in the season, but the highest frequency (and often the strongest ones) are mid-August through late September. We are potentially in for a doozy of a season this year, too–NOAA forecasters are predicting a very active season, including up to 25 named storms. According to a recent article from Yale Climate Connections, Gulf waters are hotter this May than any year since oceanographers started measuring it in 1981.
The front right quadrant of a hurricane is the strongest portion of a storm. Photo credit: Weather Nation
If you have lived in a hurricane-prone area, you know you don’t want to be on the front right side of the storm. For example, here in Pensacola, if a storm lands in western Mobile or Gulf Shores, Alabama, the impact will nail us. Meteorologists divide hurricanes up into quadrants around the center eye. Because hurricanes spin counterclockwise but move forward, the right front quadrant will take the biggest hit from the storm. A community 20 miles away but on the opposite side of a hurricane may experience little to no damage.
Flooding and storm surge are the most dangerous aspects of a hurricane. Photo credit: Carrie Stevenson, UF IFAS Extension
Hurricanes bring with them high winds, heavy rains, and storm surge. Of all those concerns, storm surge is the deadliest, accounting for about half the deaths associated with hurricanes in the past 50 years. Many waterfront residents are taken by surprise at the rapid increase in water level due to surge and wait until too late to evacuate. Storm surge is caused by the pressure of the incoming hurricane building up and pushing the surrounding water inland. Storm surge for Hurricane Katrina was 30 feet above normal sea level, causing devastating floods throughout coastal Louisiana and Mississippi. Due to the dangerous nature of storm surge, NOAA and the National Weather Service have begun announcing storm surge warnings along with hurricane and tornado warnings.
For helpful information on tropical storms and protecting your family and home, look online here for the updated Homeowner’s Handbook to Prepare for Natural Disasters, or reach out to your local Extension office for a hard copy.
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 Rick O'Connor | Apr 6, 2024
In 2005 I was leading a field trip with high school students in a salt marsh on Santa Rosa Island near Pensacola Beach. As we explored a brackish water creek, we came across a three-foot red mangrove tree, prop roots and all. To say we were surprised and excited would be an understatement.
Most know that mangroves are trees that can tolerate seawater and grow along estuarine shorelines across the tropics, including south Florida. They can form dense forests that support all sorts of aquatic and terrestrial wildlife. They need calm protected waters to establish themselves but once established are excellent at protecting shoreline communities during hurricanes. However, they cannot tolerate cold weather, only surviving freezing temperatures for one or two nights.
The red mangrove.
Photo: University of Florida
Growing up in Pensacola we would often find red mangrove propagules (seedlings) washed ashore arriving from the tropical parts of the Gulf. They were generally on the Gulf side of Santa Rosa Island and Perdido Key but never germinated. If they were carried into the estuary, and found a protected lagoon to begin germination, they would not survive our winters. This is what made finding an established three-foot mangrove in a lagoon off Santa Rosa Sound in 2005 so surprising.
Mangrove propagule washed ashore. Photo: Rick O’Connor
Historically mangroves were not found north of Tampa Bay. However, in recent decades they have become established as far north as Cedar Key. Trying to determine whether the mangrove we found was the northern most in Florida I found that they were also expanding along the east coast of Florida as far north as St. Augustine, and there were records in the Jacksonville area. Many attribute this to climate change. Our winters are milder than they were when I was a kid, and this may be leading to what many are calling the “tropicalization of northern Gulf of Mexico”. Not only mangroves, but other historically south Florida species, such as snook and bonefish, have been reported along the panhandle.
In 2017 I was leading another high school group on a field trip in a salt marsh in Big Lagoon State Park. We found a germinated seedling of a red mangrove doing very well. We explored more and found seven others in the nearby area. How many more were growing in the Pensacola Bay area?
A small red mangrove growing in Big Lagoon near Pensacola FL
Photo: Rick O’Connor
We partnered with a research team from Dauphin Island Sea Lab who was looking into this as well. The team included extension agents and specialists from Florida and Mississippi-Alabama Sea Grant, as well as biologists from the National Estuarine Research Reserves in Mississippi, Alabama, and Florida panhandle. Each county/region selected 10 transect sites that had the highest probability of mangroves to monitor each year. Mangroves appear to be established on some of the Mississippi barrier islands, as well as in St. Joe Bay. Individuals have been reported from Bay County. A ninth mangrove was found in Escambia County but a hard freeze in 2018 killed them all. Since then, one young multi-year red mangrove was found on NAS Pensacola. It died in the hard freeze of 2023. Despite the hard freezes, those established in St. Joe Bay seem to be holding on. I decided to make a visit and see.
A red mangrove growing at NAS Pensacola. Photo: Whitney Scheffel.
Black mangroves growing near St. George Island in Franklin County.
Photo: Joshua Hodson
Wading out from the buffer preserve with Gulf County Sea Grant Agent Ray Bodrey, we found relatively large patches of mangroves, and seeds suggesting active expansion was ongoing. But I noticed the species we were seeing were black mangroves. I mentioned to Ray that what we had seen in Pensacola were red mangroves. He said that the red mangroves have a hard time here as well. Black mangroves are more tolerant of cold weather, and it is they who are establishing these large patches. There are reports of large patches of mangroves on the Mississippi barrier islands – and they are the black mangroves as well. I know that black mangroves have been established in the Chandeleur Islands in Louisiana for decades. I am convinced that if black mangroves seeds were to reach protected lagoons in Pensacola Bay, they would probably do well here as well.
I continue to conduct our transects each year in the Pensacola Bay area. I have a couple of trained volunteers helping me but could always use more. If you think you have seen a mangrove growing in the Florida panhandle, we would love to know and document their location. We know they are established in Gulf County, so our focus is now Escambia to Bay counties. If you think you have seen one, contact me at roc1@ul.edu or your county Sea Grant Agent.
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.
