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.
Private well system in Florida. Image: UF/IFAS, C. Wofford
About 2.5 million Floridians rely on private wells for home consumption, which includes water for drinking, cooking, and personal hygiene. Private wells are not regulated by the EPA Clean Water Act, and well users are responsible for ensuring their water is safe to drink.
What should you have your well water tested for?
The Florida Department of Health (FDOH) recommends that well users test their well water once a year for bacteria at a minimum. Another important contaminant to test for is nitrate.
Bacteria: Labs generally test for total coliform (TC) bacteria and fecal coliforms (like E. coli).
Coliform bacteria are a large group of bacteria and most are harmless. But a positive test result indicates that if they are in your water, other pathogens that cause diseases may also be present. They are used as indicator organisms.
Fecal coliform bacteria are a subgroup of coliform bacteria found in human and other warm-blooded animal feces. E. coli are one species and some strains can cause diarrhea, food poisoning and other illnesses.
If your water sample tests positive for only total coliform bacteria or both TC and fecal coliform (E. coli), FDOH recommends your well be disinfected through shock chlorination. You can either hire a well contractor to do this or you can do it yourself. Information for how to shock chlorinate your well can be found at EDIS Private Wells 101: Bacterial Contamination and Shock Chlorination
Take a water sample at the kitchen faucet if this is where you get most of the water that your household consumes. Image: F. Alvarado
Nitrate: The U.S. EPA set the Maximum Contaminant Level (MCL) allowed for nitrate in drinking water at 10 milligrams per liter of water (mg/L). Values above this are a particular concern for infants less than 6 months old because high nitrate levels can cause a type of “blue baby syndrome” (methemoglobinemia), where nitrate interferes with the capacity of hemoglobin in the blood to carry oxygen. It is especially important to test for nitrate if you have a young infant in the home that will be drinking well water or when well water will be used to make formula to feed the infant.
If test results come back above 10 mg/L, never boil nitrate contaminated water as a form of treatment. This will not remove nitrates. Use water from a tested source (bottled water or water from a public supply source) until the problem is addressed. Nitrate in well water can come from multiple sources, including fertilizers, animal waste and/or human sewage, such as from a septic tank.
You should also have your well water tested at any time when:
The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
A new well is drilled or if you have had maintenance done on your existing well
A flood occurred and your well was affected
Remember: Bacteria and nitrate are by no means the only parameters that well water is tested for. Call your local health department to discuss what they recommend you should get the water tested for. FDOH also maintains an excellent website with many resources for private well users which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.
Where can you have your well water tested?
UF/IFAS Extension will be hosting a private well and water quality workshop on April 11 in Blountstown, with a Zoom option. We will cover well and septic system function and maintenance, water testing and how to prepare for hurricane season. We will also offer facilitated water testing. For more information and to register go to our Eventbrite link or you can also register by visiting the Calhoun County Extension Office, (850-674-8323). Last week’s post about the workshop provides more information as well.
In general, many county health departments accept samples for water testing. You can also submit samples to a certified commercial lab near you. Contact your county health department for information about what to have your water tested for. If they don’t offer testing, they often provide the name of certified laboratories near you. Or you can search for FDEP certified laboratories here.
If you have any questions, you can also reach out to me at albertin@ufl.edu or (850)875-7111.
Join us for our upcoming multi-county private well and water quality workshop. As a private well user, you are responsible for ensuring that your water is safe to drink. We will cover how private wells and septic systems work, proper maintenance, steps to help ensure your drinking water is safe to consume and disaster preparedness for this upcoming hurricane season. We will also offer facilitated water testing for bacteria, lead and nitrate.
The workshop will be offered on Thursday, April 11, 2024, from 9:00 am – 11:30 am CST at the Calhoun County Extension Offices, 20816 Central Ave. E, Blountstown. You can also attend virtually via Zoom. Registration is $5.00 per person. Facilitated water screening for total coliform and E. coli bacteria is available at a reduced cost. Please register on Eventbrite, https://JacksonCountyFCS.Eventbrite.com/ or you can also register by visiting the Calhoun County Extension Office, (850-674-8323). This workshop is being presented by UF/IFAS Extension Bay, Calhoun, Holmes, Jackson, and Washington Counties.
For lead and nitrate testing prices and additional details, visit our Eventbrite page or call the Calhoun County Extension Office at 850-674-8323. Pre-registration is encouraged as seating is limited, but as mentioned previously, a virtual option is also available. For persons with disabilities requiring special accommodations, please contact the Extension Office (TDD, via Florida Relay Service, 1-800-955-8771) at least ten working days prior to the class so that proper consideration may be given to the request. UF/IFAS Extension is an Equal Opportunity Institution.
You might have seen a floating oyster farm while driving over Garcon Point Bridge or along Scenic Highway. Many people know them for the beautiful, tasty oysters they produce, but those farms have a major ecological benefit that many aren’t aware of. First, the oysters in those cages act as a very efficient water filter, filtering upwards of 30 gallons per day. The floating farms also act as an oasis for other marine creatures, from crustaceans to finfish, and can help increase the biodiversity in the area. Oysters are also great at sequestering carbon into their shells. Today, we will go over these ecological benefits and proper etiquette when maneuvering around the farms to enjoy some of the ecological benefits of the oyster farm.
Florida Pompano Caught Off an Oyster Farm – Thomas Derbes II
Besides being tasty, oysters are very well known for their ability to filter massive amounts of water in a single day. Research has shown rates of up to 50 gallons per day in a laboratory setting, but they filter upwards of 30 gallons per day in the wild. With most oyster farms in the area having more than 500,000 oysters on their farm, that’s more than 15,000,000 gallons of water per day per farm! Oysters can filter out any excess sediments from the water, forming them into small packets and depositing the sediment on the bottom of the bay, keeping the sediments from being re-suspended. This is very beneficial to any bay or estuary as eutrophication (More Here on Eutrophication) has been an issue in almost every bay in the southern United States.
Another benefit to oyster farms is that it is a floating oasis for all types of marine creatures. Blue crabs and stone crabs are a common threat to oysters, and they love to congregate around oyster farms waiting for an easy meal from a dropped oyster or oyster spat on cages. Common bay fish, like the Spotted Seatrout, Sheepshead, and Red Drum, have been known to hang out under the cages consuming smaller finfish and crabs, but some uncommon fish like Tripletail and Florida Pompano also patrol the cages looking for a meal. Because of its ability to hold all types of fish, fishermen love to fish around the oyster farms. Fishing around oyster farms is allowed, but most farmers want the boats to stay on the boundary of the farm and not inside of it. This is due to there being lines under the surface of the water that could potentially damage any lower unit and can cut free a line of cages. Also, it is against state law to be within the boundary of the farm if you are not an authorized harvester of that lease, and I have personally seen FWC enforce those rules. As a seasoned oyster farmer once told me “We know our farm holds fish and it is okay for them to fish the farm, heck put out some blue crab traps around it, but do not mess with the cages and stay outside of the boundary and we can all live in harmony.”
Tripletail Caught Off An Oyster Farm – Brandon Smith
Last but not least is the ability of oysters to sequester carbon and excess nitrogen into their shells and pseudofaeces (aka bio-deposits). Carbon and nitrogen sequestration is a crucial service provided by oysters that helps battle global climate change. Just as they do with excess sediments, they deposit excess carbon and nitrogen into bio-deposits that accumulate on the bottom, keeping them from being re-suspended into the waters. Oyster reefs are currently on the decline around the world, and their decline has “resulted in a forfeiture of several ecosystem services” including carbon and nitrogen sequestration and water filtration. (More Here on Carbon Sequestration)
While oysters might be tasty, we have learned about some of the ecological services oysters provide to an estuarine environment. From water filtration to increasing biodiversity to carbon/nitrogen sequestration, oysters are a major benefit to any estuary and can help fight climate change and eutrophication. Next time you see an oyster farm or reef, give oysters (and farmers) a little appreciation for their hard work in helping make the world a healthier place!
And it’s a good thing! Green gill oysters are prized in the oyster community. In the Carolinas and Northern France, green gill oysters are a seasonal, cherished crop and a product of the saying “You are what you eat!” The phytoplankton, Haslea ostrearia, is the typical culprit, and their distribution is measured by direct observation from plankton tows or the occurrence of green-gilled oysters. The exact distribution is unknown, but there are reports of H. ostrearia throughout the Atlantic, Pacific, and Indian oceans. Haslea ostrearia is a beautiful pennate diatom that contains a water-soluble blue pigment known as marennine (More Here). Marennine’s production is stimulated by long photoperiods, blue light, and high light/low cloud weather. It can also be released into the water and into the flesh of organisms (typically oysters) that consume them.
Fresh out of the water Grayson Bay Oyster with green gills! – Brandon Smith, Grayson Bay Oyster Company
Pensacola Bay, and surrounding areas, had a pretty mild fall in terms of rainfall, and the bays have turned a beautiful green-blue hue as the bays have risen in salinity and phytoplankton typically found in the Gulf of Mexico were able to survive. Brandon Smith, owner of Grayson Bay Oyster Company, was out working his farm January 7th, 2024, and sent a text to me saying “take note of the green gills,” and I was very shocked and happy to see actual, green-gilled oysters in our local waterways. He graciously harvested a few dozen to examine (and let me taste test), and I was able to confirm the presence of green gills in the oysters. After further research on H. ostrearia, it seems as though the pennate diatom made it into our bays and is the culprit of this wonderful surprise.
A local Grayson Bay Oyster displaying green-gills – Thomas Derbes II
When I shucked my graciously donated oysters from Grayson Bay, I was reminiscing on the first time I came across green-gilled oysters. The first batch of green gill oysters I ate came from an oyster farm in North Carolina called N. Sea Oyster Company. Their green-gilled beauties “Divine Pines” were requested by a wedding I was catering for, and I was able to slurp down one to get talking and tasting notes. The seasonal Divine Pines offered a sweet yet salty taste and became one of my favorite out-of-area oysters to serve at events and to personally consume. While beautiful, the green-gilled oysters are usually only found in the fall/winter months. These green-gilled Grayson Bays were very comparable and offered a salty yet very sweet and minerally finish. The H. ostrearia is responsible for not only the green gills, but the sweet tasting notes, and I highly recommend adding any green-gilled oyster to your fall/winter raw bar selection.
References:
Turpin, Vincent & Robert, J-M & Philippe, Goulletquer & Massé, Guillaume & Rosa, Philippe. (2008). Oyster greening by outdoor mass culture of the diatom Haslea ostrearia Simonsen in enriched seawater. Aquaculture Research. 32. 801 – 809.
When I was hired with Florida Sea Grant, I developed an advisory committee who represented a variety of stakeholder interest in the Pensacola Bay area. I asked the committee to list their top three concerns or issues with the local marine environment so that I could have a start on where I would focus my education programs. I was expecting a variety of answers, but all of them wrote water quality.
Each October I send a survey to those who have read one of my articles, or attended one of my programs to see what behavior changes they may have made to improve the health of the bay and I ask them which topics should be the focus for the upcoming year. Water quality is always on that list and is usually the first. 2024, was no different, water quality remains the number one topic.
Local bayous in the Pensacola Bay area have experienced fish kills due excessive nutrients in the past. The Lakewatch Program trains volunteers to monitor nutrients in these waterways today.
Photo: Rick O’Connor
There are numerous issues that impact our water quality. In a 2016 EPA publication, Dr. Mike Lewis (et.al.) discussed a variety of environmental concerns that had impacted the Pensacola Bay System1. Between pages 23-86 of this 145-page document the topic of water quality is discussed. Topics include what contaminants we discharge into the waterways, ground water quality, surface water quality, sediment quality, bioaccumulation, and the risk these contaminants have on estuarine fish and wildlife, as well as humans. The contaminants reach our waters using a variety of ways including the atmosphere, ground water, tributaries, municipal and industrial wastewater, and stormwater runoff. With a variety of issues at hand, I asked my advisory committee for advice on prioritizing these issues. Surface water quality rose to the top and I began our program here.
Surface waters have issues such as eutrophication (excess nutrients triggering algal blooms which trigger low dissolved oxygen which trigger fish kills), chemical contamination of sediments, water clarity due to increase sediments, fecal bacteria, PAHs, pesticides, PCBs, and others. Many of these have been monitored for decades. Surface water quality in the Pensacola Bay System was reported as fair in 1992, in need of improvement in 1998, and good – 30% good in 2005. Though things are improving there is still much to do.
So… what can YOU do the help?
Historically rainwater fell on the land and water of the Pensacola Bay region. The water that fell on the land either percolated through the sediments to recharge the ground water, or – if it was a form of sediment that reduced percolation rates, formed surface water that recharged the bay (streams, creeks, and rivers). With the increase in development there came an increase in impervious surfaces for water to percolate, and flooding of streets and communities became a problem. Communities began to develop methods of moving this stormwater into our properties and into the area waterways. Early the method was nothing more than discharge pipes directly into these waterways. More recently stormwater ponds, diverting to marshes, and other methods have been used. This has become an increasing problem with the high densities developments we are seeing now.
Stormwater conveyance in Santa Rosa and Escambia counties. Photo: Matt Deitch
Solving this problem often falls on the city and county governments to develop ordinances to properly manage stormwater and abide by state and federal mandates. Each year, UF IFAS Extension offers a district wide workshop focused on new methods of handling stormwater. This year Part 1 of the workshop will be held on May 1, Part 2 on May 15. If you are with a city/county municipality and are interested in attending either in-person or virtually, contact your local extension office for more information. But there are things that private homeowners and businesses can do as well.
Everyone who lives in the Florida panhandle can expect rain and a lot of it. Over the last decade Pensacola has averaged around 70 inches annually. What are you going to do with the rainwater that falls on your property? In many cases there are designs for it to run off your property and contribute to the stormwater issue. However, there are ways to hold on to that rainwater and use it for good. If you have gutters you can place rain barrels at the down spouts. This water could then be used to irrigate your landscape using drip irrigation methods. You could create a rain garden. These are low areas on the property where rainwater is directed. You can then landscape these with plants that can tolerate wetter conditions and make it look attractive. You can also use previous materials for your sidewalks, patios, and even your driveway. Pervious materials will allow rainwater to percolate through reaching the ground and avoid running off towards storm drains.
Rain barrels can be used to capture rainwater and avoid run-off. Rain garden at the VA Central Western Massachusetts Health Care System facility.
Photo: US Air Force
You could landscape your yard using the UF IFAS Florida Friendly Landscaping principles. Following the nine principles of this program will help reduce the need for fertilizers, pesticides, and water usage itself. Not only does this reduce irrigation water becoming part of the stormwater, but it also reduces some of the chemical pollutants that contribute to poor water quality as well. It also saves the property owner money.
Health advisories issued due to high levels of fecal bacteria are problems in many local waterways. Poorly maintained septic and sewer systems are a major cause of this. If you own a septic system, you need to develop a maintenance plan and follow it. If you are not sure how to do this, contact your county extension office for assistance.
A conventional septic system is composed of a septic tank and a drainfield, where most of the wastewater treatment takes place. Image: US EPA
Though less maintenance is needed if you are on sewer system, there are still things you need to do to help reduce sanitary sewage overflows (SSOs). One is to watch what you pour down the drain. Fats, oils, grease, and even milk can solidify and block the flow of your sewage, and lead to SSOs. In Escambia County the Emerald Coast Utility Authority (ECUA) offers a program they call FOG. This program provides free containers where you pour your fats, oils, and grease. When full, they can be exchanged for a new container, this reduces the frequency of SSOs and ECUA will use these oils as a biofuel at their reclamation center. There may be a similar program in your community. Another practice you could adopt is to check the lateral sewer lines connecting your house to the main sewer line under the street. These lateral lines are the responsibility of the homeowner and can become clogged or cracked releasing untreated sewage into the environment.
1-gallon container provided free to dispose of your oil and grease.
Photo: Rick O’Connor
If you are a waterfront property owner, you might consider planting a living shoreline. These natural shorelines not only reduce the erosion of your property, but they also provide habitat that enhances fisheries, and the marsh plants are good at absorbing/trapping sediments and pollutants that may runoff your property. If you would like to learn more about how to have a living shoreline planted, contact your county extension office.
FDEP planting a living shoreline on Bayou Texar in Pensacola.
Photo: FDEP
Keep in mind that the suggestions mentioned above work as well for businesses as they do for homeowners.
It is understood that water quality is a large concern for many in the Florida panhandle. Though things are improving in some areas, there is more that can be done. There are things YOU can do to help reduce this problem. Hopefully some of you will adopt some of the practices in 2024 and let us know if you do. If you have questions about any of them, contact your local county extension office.
Reference
1 Lewis, Michael, J. Taylor Kirschenfeld, and Traci Goodhart. Environmental Quality of the Pensacola Bay System: Retrospective Review for Future Resource Management and Rehabilitation. U.S. Environmental Protection Agency, Gulf Breeze, Florida, EPA/600/R-16/169, 2016.
