by Thomas Derbes II | May 10, 2024
The Panhandle of Florida is home to many estuaries along the coast, from the Escambia Bay System in the west to the Apalachicola Bay System in the east. These estuaries are very important and are the intersection where rivers (fed from their respective watersheds) meet the Gulf of Mexico and contain many different organisms that help filter the waters before they reach the Gulf. These organisms include oysters, marsh plants, seagrasses, scallops, tunicates, and other invertebrates. In this two-part article, we will explore marsh plants, seagrasses, oysters, and scallops.
Marsh Plants
Marsh Plants is a broad term for a family of grasses that lines the shore and contain grasses like Smooth Cordgrass (Spartina alterniflora), Saltgrass (Distichlis spicata), and Gulf Cordgrass (Spartina spartinae). These plants help trap sediments before they enter the estuary and are excellent at erosion prevention. When the water encounters the plants, it slows the flow, and this allows for sediments to collect. Marsh Plants are a great tool for shoreline restoration and are a major part of the Living Shorelines Program. The roots of the plants are also very efficient at removing nutrient pollutants like excess nitrogen and phosphorus which are major influencers in eutrophication. Marsh Plants also absorb carbon dioxide from the atmosphere and have been tabbed as “superstars of CO2 capture and storage.” (CO2 and Marsh Plants)
Marsh Grass and Oyster Reef in Apalachicola, Florida – Thomas Derbes II
Seagrasses
Seagrasses are different than Marsh Grasses (seagrasses are ALWAYS submerged underwater), but they offer some of the same ecological services as Marsh Grasses. The term seagrasses include Turtle Grass (Thalassia testudinum), Shoal Grass (Halodule wrightii), Widgeon Grass (Ruppia maritima), and Manatee Grass (Syringodium filiforme) to name a few. Seagrasses help maintain water clarity by trapping suspended sediments and particles with their leaves and uptake excess nutrients in their roots. Seagrasses are very efficient at capturing carbon, capturing it at rates up to 35 times faster than tropical rainforests. (Carbon Capture and Seagrasses) They also provide habitat for crustaceans, fish, and shellfish (which can filter the water too) and food for other organisms like turtles and manatees.
Grassbeds are also full of life, albeit small creatures.
Photo: Virginia Sea Grant
Oysters
Crassostrea virginica (or as we know them, the Eastern oyster) is a native species of oyster that is commonly found along the eastern coast of the USA, from the upper New England states all the way to the southernmost tip of Texas. Eastern oysters are prolific filter feeders and can filter between 30-50 gallons of water per day. As filter feeders, they trap nutrients like plankton and algae from the environment. In areas of high eutrophication, oysters can be very beneficial in clearing the waters by trapping and consuming the excess nutrients and sediments and depositing them on the bottom as pseudo-feces. With oyster farms popping up all over the Gulf Coast, the filtering potential of estuaries is on the rise. (Between the Hinge)
Oysters, The Powerful Filterers of the Estuary – Thomas Derbes II
Scallops
Bay Scallops (Agropecten irradians) were common along the whole Florida Gulf Coast, but their numbers have taken a recent decline and can only be found in abundance in the estuaries to the east of St. Andrews Bay in Panama City, Florida. Scallops make their home in seagrass beds and are filter feeders. While scallops do not contain the filtering potential of an oyster (scallops filter 3 gallons of water per day as an adult), they are still a key part of filtering the estuary. Just like oysters, scallops feed off of the suspended particles and plankton in the water column and deposit them as pseudo-feces on the bottom. The pseudo-feces also help provide nutrients to the seagrasses below.
Bay Scallop.
Photo: FWC
I hope you enjoyed this first article on filterers in the estuary system. While oysters are known as the filterers of the estuary, I hope this has opened your eyes to the many different filterers that call our estuary home. Stay tuned for Part 2!
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 Carrie Stevenson | Jan 8, 2021
Well-maintained stormwater ponds can become attractive amenities that also improve water quality. Photo credit: Carrie Stevenson, UF IFAS Extension
Prior to joining UF IFAS Extension, I spent three years as a compliance and enforcement field inspector with the local Florida Department of Environmental Protection (FDEP) office. It was a crash course in drinking water regulation, wetlands ecology, stormwater engineering, and human psychology. For about half of that time, I worked in the stormwater section with an engineer, certifying the proper construction and specifications of stormwater treatment ponds built for residential and commercial developments. During a construction boom in 2000-2003, my coworkers and I traversed back roads from Perdido Key to Freeport, trying to catch every new project and make sure it was done right. If they weren’t, it also fell to the 3 of us to make sure mistakes were corrected.
Since 1982, Florida Statutes have required that rainfall landing on newly constructed impervious surfaces (rooftops, streets, parking lots, etc.) must be treated before turning into runoff that leaves the property and ends up in local water bodies. The pollutants in stormwater runoff—heavy metals, fertilizer, pesticides, trash, bacteria, and sediment—are the biggest sources of water quality problems for the state, more so even than industrial and agricultural sources.
The most common stormwater ponds have sandy bottoms, grassed berms, and piped inlets with riprap to slow the influx of water. Photo credit, Michelle Diller
Therefore, new developments are required to treat that runoff. This may be accomplished by several means, including regional stormwater ponds. However, the most common are still curbs and gutters, which drain to an often-rectangular hole in the ground with a chain-link fence around it. Ideally, water pools into these dry ponds while raining, reducing flood risk and holding water long enough to allow it to soak into the soil. Most of the ponds in northwest Florida have sandy bottoms that percolate easily. Maintenance is required, however, and when heavier soils, trash, or muck accumulate they must be cleaned out to function properly. Depending on the geology of any given location, the ponds may need sand filters or “chimneys” added to allow water to soak into the native soil.
Admiral Mason Park, adjacent to the Veterans’ Memorial Park along Pensacola Bay, is an example of a regional City stormwater treatment facility that also serves as a park. Photo credit: Visit Pensacola
If an area is naturally low-lying, close to the water table, or has highly organic, water-holding soils, it may be necessary to construct a “wet” stormwater pond. In these, water stands to a level below an overflow device, and can become a water feature for the development. Many residential developers will sell lots around a stormwater pond as “waterfront property” and a well-maintained one really can be a nice amenity. However, at their core, these are stormwater treatment mechanisms. A wet pond functions differently than a dry one and is dependent on healthy stands of shoreline vegetation to take up extra nutrients, metabolize them, and render them into harmless compounds. Many of these ponds have fountains to aerate the water and keep them from becoming stagnant. The City of Pensacola and Escambia County have several great examples of these types of ponds that serve as regional stormwater detention and community amenities. These were constructed in lower-lying areas to handle chronic problems with stormwater in areas that were built up and paved many decades before stormwater rules came into effect. Many other innovative and newer stormwater treatments exist as well, including bioretention, rainwater harvesting, green roofs, and pervious pavement.
by Shep Eubanks | Sep 13, 2019
Common Salvinia Covering Farm pond in Gadsden County
Photo Credit – Shep Eubanks UF/IFAS Gadsden County Extension
Close up of common Salvinia
Photo Credit – Shep Eubanks UF/IFAS Gadsden County Extension
Aquatic weed problems are common in the panhandle of Florida. Common Salvinia (Salvinia minima) is a persistent invasive weed problem found in many ponds in Gadsden County. There are ten species of salvinia in the tropical Americas but none are native to Florida. They are actually floating ferns that measure about 3/4 inch in length. Typically it is found in still waters that contain high organic matter. It can be found free-floating or in the mud. The leaves are round to somewhat broadly elliptic, (0.4–1 in long), with the upper surface having 4-pronged hairs and the lower surface is hairy. It commonly occurs in freshwater ponds and swamps from the peninsula to the central panhandle of Florida.
Reproduction is by spores, or fragmentation of plants, and it can proliferate rapidly allowing it to be an aggressive invasive species. When these colonies cover the surface of a pond as pictured above they need to be controlled as the risk of oxygen depletion and fish kill is a possibility. If the pond is heavily infested with weeds, it may be possible (depending on the herbicide chosen) to treat the pond in sections and let each section decompose for about two weeks before treating another section. Aeration, particularly at night, for several days after treatment may help control the oxygen depletion.
Control measures include raking or seining, but remember that fragmentation propagates the plant. Grass carp will consume salvinia but are usually not effective for total control. Chemical control measures include :carfentrazone, diquat, fluridone, flumioxazin, glyphosate, imazamox, and penoxsulam.
For more information reference these IFAS publications:
Efficacy of Herbicide Active ingredients Against Aquatic Weeds
Common salvinia
For help with controlling Common salvinia consult with your local Extension Agent for weed control recommendations, as needed.
by Laura Tiu | Sep 23, 2016
Rocky Bayou Aquatic Preserve – Choctawhatchee Bay, Niceville, Florida – Photo by Laura Tiu
September 17-24, 2016 was the nation’s 28th time to celebrate America’s coasts and estuaries during National Estuaries Week. This week helps us to remember to appreciate the challenges these coastal ecosystems face, along with their beauty and utility.
Estuaries, semi-enclosed bodies of water with both fresh and saltwater, dot the Gulf Coast of the United States from Brownsville Texas to Key West, Florida. These estuaries are important as they serve as drainage basins for many of the large river systems, and play a significant role in the nation’s seafood industry.
Florida’s six major Panhandle estuaries, which includes Perdido Bay, Pensacola Bay (including Escambia Bay), Choctawhatchee Bay, St. Andrew Bay, St. Joseph Bay and Apalachicola Bay, are unique ecosystems teeming with life and diversity. Critical habitat includes important seagrass beds that support both the larval and adult stages of fish and invertebrates. In Choctawhatchee Bay, there is also critical foraging habitat for the federally protected Gulf sturgeon (Acipenser oxyrinchus desotoi) and stream habitat for the endangered Okaloosa darter.
Choctawhatchee Bay is in Okaloosa and Walton counties in the Florida Panhandle. It is approximately 30 miles long and from three and a half to six miles wide, with a total area of 129 square miles. It is relatively shallow varying from 10 to 40 feet deep. Large portions of the western half of Choctawhatchee Bay are militarily restricted (Eglin Airforce Base). The Bay is fed by the Choctawhatchee River and numerous small creeks that feed into several bayous. The only opening to the Gulf of Mexico is the East Pass, which ironically is at the Western end of the Bay in Destin, Florida. This is where the saltwater and freshwater mix.
Continued industrial and residential development in the watershed regions that drain into many of these estuaries has impacted them in a number of ways. Pollution comes from storm water runoff, lawns, industry and farms. The shorelines are impacted by development, which causes sedimentation and in turn loss of vegetation. This reduces water clarity and habitat for wildlife.
Many organizations work to protect this estuary and reach out to others through education, restoration, and recreation events. Choctawhatchee Basin Alliance (CBA) is one such organization committed to ensuring sustainable utilization of the Choctawhatchee River and Bay. They, working with their partners, provide leadership for the stewardship of the Bay. Alison McDowell, director of the CBA, notes that 75-85% of commercially and recreationally important species that are caught in the Gulf spend part of their lifecycle in the Bay. McDowell says a key factor in the Bay’s health is monitoring the water quality and reducing erosion, and the Oyster Reef Restoration program started in 2006 does just that.
There are often opportunities for the general public to join in some of the conservation efforts taking place in the Bay. For more information, like the Okaloosa or Walton County Extension Facebook page.
Kayaking Choctawhatchee Bay – Photo by Laura Tiu
by Carrie Stevenson | Feb 5, 2016
On “project day” students share their knowledge with the class. Photo credit: Carrie Stevenson
The Florida Master Naturalist Program is a 40-hour experiential learning course offered by UF IFAS Extension. While we spend time in class with presentations, by far everyone’s favorite aspects of the course are field trips and “project day.” As part of the course, each participant produces an educational tool—a display, presentation, skit, or lesson—that delves deeper into a topic of interest. The students and instructors are able to use these tools again and again to teach others.
Master Naturalist students walk “The Way” boardwalk in Perdido Key. Photo credit: Carrie Stevenson
One example of a multi-year student project is “The Way” nature trail, located at Perdido Bay United Methodist Church. Master Naturalist Jerry Patee worked with volunteers from his church and community to design and permit a boardwalk and nature trail leading to Bayou Garcon. The unique trail is less than a mile, but traverses upland, freshwater wetland, and coastal habitats, making it a perfect ecological teaching tool. The trail is open to the public and maintained as a place of quiet contemplation. The project is ongoing, with educational signage planned, but it is an excellent new resource for the community.
“The Way” is just one of many positive contributions made by Master Naturalist students over the years. To enroll in a Florida Master Naturalist course near you, visit the FMNP page or talk with an instructor at your local county Extension office.
