by Rick O'Connor | May 25, 2018
In the mid 1990’s, the Bay Area Resource Council was created. This multi-county (Escambia and Santa Rosa) organization included local scientists and decision makers to help better understand the health of Pensacola Bay, develop a plan for restoration, and work collaboratively to acquire funding to do so. At the inaugural meeting, many different scientists spoke on a variety of topics. There were several take-home messages – one of them was that sediments of Pensacola Bay were in poorer health than the water within the water column above it.
Grabs are used by marine scientist to collect samples of sediments from the bottom of the bay.
Photo: Coastal Science NOAA
So, what is wrong with the sediments, and how has this changed since the mid ‘90’s?
Based on sediment sample analysis, some researchers consider the Pensacola Bay System the most polluted in the state of Florida… but not everyone. The three bayous (Chico, Texar, and Grande), Escambia Bay, and the downtown waterfront of Pensacola Bay had some of the poorest sediment samples within the system. Contaminants monitored include trace metals, mercury, non-nutrient organics, pesticides, and dioxins. These contaminants are dense and do not remain in the water column long. Instead, they sink into the sediments. At that time, some suggested that attempts to remove the contaminants could increase their levels within the water column and do more harm than good – thinking it would be better to leave the sediments as they are. Many of the compounds entered the estuary through run-off. In some cases in the past, they were discharged directly into a bay or river.
Chemicals found in Pensacola estuarine sediments include Arsenic, Zinc, and Copper. Mercury levels at some locations in the bay are higher than other estuaries around the northern Gulf region. Some non-nutrient organic compounds were not as high as other local estuaries however; bioaccumulation (the increase in contaminant concentrations via the food chain) has been occurring and should be monitored. Many chemical compounds banned in the 1970’s have long half-lives and are still detected in the sediments today. Chlorinated pesticides, such as dieldrin, chlordane, DDE, DDD, and DDT are still found in the bayous – and at higher concentrations than neighboring estuaries.
This all sounds bad, but are the levels high enough to be toxic to marine organisms?
Herbicides and pesticides can find their way into estuarine systems and contaminate the sediments.
Photo: UF IFAS Washington County Extension
One location, in upper Bayou Texar, seems to be quite toxic to the species of bacteria, invertebrates, fish, and plants tested. These toxic concentrations are partially from chemicals present in run-off, but there is also seepage coming from groundwater contaminated from a nearby Superfund site. Most of the test suggest that the lethal concentrations are more chronic in nature than acute.
So what can be done? What can we do?
Well… removing and treating these sediments is quite expensive and is not an option at this time. There are plans to dredge portions of Bayou Chico but the process has undergone extensive scrutiny and permitting. One thing we can do is reduce the amount that is still entering the bay. How do we do this?
- Consider re-landscaping your yard to be “Florida Friendly”. Using the suggestions given within this University of Florida program (http://fyn.ifas.ufl.edu/) you can reduce the amount of fertilizer, herbicide, and pesticides you use – thus reducing the amount entering the estuaries.
- Florida Friendly Landscaping practices can also reduce the amount of watering your lawn needs. This reduces the amount of run-off reaching the bay and always reduces the amount of money you spend on watering and lawn chemicals.
- The Florida Department of Environmental Protection’s Clean Boater program provides tips and suggestions that reduce the amount of hazardous chemicals that enter the bay from cleaning and maintaining vessels. https://floridadep.gov/fco/cva/content/clean-boater-program.
The sediments of the bay have suffered the abuse of the past. However, with better practices, we can reduce our impact in the future.
Florida Friendly Landscaping saves money and reduces our impact on the estuarine environment.
Photo: UF IFAS
Reference
Lewis, M.J., J.T. Kirschenfeld, T. Goodhart. 2016. Environmental Quality of the Pensacola Bay System: Retrospective Review for Future Resource Management and Rehabilitation. U.S. Environmental Protection Agency. Gulf Breeze FL. EPA/600/R-16/169.
by Rick O'Connor | May 25, 2018
In recent weeks, volunteers and I have been surveying local estuaries counting terrapins, horseshoe crabs, and monitoring seagrass. One animal that has been very visible during these surveys is the relatively large snail known as the crown conch (Melongena corona). Its shell is often found with a striped hermit crab living within, but it is actually produced by a fleshy snail, who is a predator to those slow enough for it to catch.
The white spines along the whorl give this snail its common name – crown conch.
Photo: Rick O’Connor
The shell is familiar to most who venture to the estuary side of our beaches. Reaching around five inches in length, crown conch shells are spiral with a wide aperture (opening) and brown to purple to white in color. Each whorl ends with white spins giving it the appearance of a crown and – hence – it’s common name. They are typically seen cruising along the sediments near grassbeds, salt marshes and oyster reefs – their long black siphons extended drawing in seawater for oxygen, but also to detect scents that will lead them to food.
These snails breed from winter to early summer. Females, larger than males, will develop 15-500 eggs in capsules, which they attach to hard structures within the habitat; such as wood, seagrass blades, and shell material.
Crown conchs are subtropical species and have a low tolerance for cold water. They are common in the panhandle and may expand further north along the Atlantic coast if warming trends continue. They have a higher tolerance for changes in salinity and can tolerate salinity as low as 8 ppt. The salinities within Pensacola Bay can be as low as 10 ppt and Santa Rosa Sound / Big Lagoon are typically between 20-30 ppt. The developing young require higher salinities and thus breeding takes in the lower portions of our estuaries.
These are guys are snail predators – seeking prey slow enough for them to catch. Common targets include the bivalves such as oysters and clams, but they are known to seek out other snails – like whelks. Crown conchs are known to feed on dead organisms they encounter and may be cannibalistic. As with all creatures, they have their predators as well. The large thick shell protects them from most but other snails, such as whelks and murex, are known predators of the crown conch.
These conchs tend to stay closer to shallow water (less than 3 ft.) due the large number of predators at depth. They are common in seagrass meadows and salt marshes and – if in high numbers with few competitors – have been considered an indicator of poor water quality. There is no economic market for them but they are monitored due to the fact they affect the populations of commercially important oysters and clams.
The “snorkel” is called a siphon and is used by the snail to draw water into the mantle cavity. Here it can extract oxygen and detect the scent of prey.
Photo: Franklin County Extension
It is an interesting animal, a sort of “jaws” of the snail world, and a possible candidate for a citizen science water quality monitoring project. Enjoy exploring your coastal estuaries this summer and discover some of these interesting animals.
Reference
Masterson, J. 2008. Indian River Lagoon Species Inventory: Crown Conch Melongena corona. Smithsonian Marine Station at Ft. Pierce, Florida. http://www.sms.si.edu/irlspec/Melongena_corona.htm.
by Rick O'Connor | May 12, 2018
Records of the variety of aquatic life in Pensacola Bay go back to the 18th century. According to these reports, over 1400 species of plants and animals call Pensacola Bay home. Many of them depend on seagrass, oyster reefs, or marshes to complete their life cycle. The greatest diversity and abundance are found on the oyster reefs. Finfish and shellfish in the bay have sustained humans as a food source for centuries. However, we know that the alligator, turtles, and a variety of birds and mammals have also been important. In this article, we will focus on the aquatic species.
Red Drum – photo credit Florida Fish and Wildlife
When people think of aquatic life in the bay, they first think of fish. About 200 species call Pensacola Bay home. The most abundant are the true estuarine fish, such as croakers, sardines, and minnows. There are a variety of marine transient fish that can be found such as jacks, mackerels, and some species of sharks. Spot and Atlantic Croaker are the most abundant members of the croaker family, and are still an important target fish for locals. Anyone who has snorkeled or cast a line with cut bait knows how common pinfish can be, and those who have pulled bait nets are very familiar with the silverside minnows and anchovies.
I have pulled many a seine net over the years assessing the diversity and abundance of the nearshore fish populations and logged 101 species. In addition to those listed above, killifish (also locally known as “bull minnows”) are a common capture. For a few years, we were involved in trawling in deeper waters where we collected a variety of flounder, silver perch, grunts and snapper. Sea robins are an interesting member of our community and gag grouper were captured occasionally. The number and variety of fish found varies with seasons and is greatest in June. The diversity and abundance of estuarine fishes in our bay is very similar to neighboring estuaries.
The second thing people think of when they think of aquatic life in the bay are shellfish. These would include the crabs, shrimp, and oysters. However, the most abundant macro-invertebrates in our bay are those that can tolerate environmental stress and live in the surface layers of the sediments – these are the worms and crustaceans. There are numerous varieties of segmented polychaete worms, who are famous for building tunnels with “volcano” openings. They are also common within oyster reefs, feeding on all sorts of organic debris. Blue crab are common throughout the bay and provided both a commercial and recreational fishery for years. Brown and white shrimp are both found and have been the most popular seafood with locals for years.
The famous blue crab.
Photo: FWC
During my lifetime, the only marine mammal commonly seen has been the Atlantic Bottlenose Dolphin, and these are found in many parts of the bay. Years back, I heard accounts of harbor porpoise, but never actually saw one. An historic occurring marine mammal, who seems to be making a comeback, is the Florida Manatee. Sightings of this animal have been reported in a variety of locations in recent years.
Snakes, turtles, and alligators are all found in the bay area. There is really only one saline snake and this is the gulf coast salt marsh snake. However, nontraditional estuarine snakes, such as the cottonmouth, are becoming more common in and near the bay. Though we have a great variety of turtles in our rivers, only one true estuarine turtle exist in the country, the diamondback terrapin – and this turtle can be found in parts of our bay. Sea turtles do venture into the bay searching for food, particularly the green turtle who is fond of seagrasses.
Many forget the small planktonic animals that drift in the water column, but they are there – about 100 species of them. Copepods are small roach looking crustaceans that are by far the most abundant member of the zooplankton, particularly the species known as Acartia tonsa – which makes up 82% of the abundance in our bay. These small animals are an important link in the food chain of almost every other member of the bay community. The zooplankton variety in Pensacola Bay is very similar to those of neighboring estuaries.
And then there are the plants…
By far, the most diverse group of organisms in the bay are the microscopic plants known as phytoplankton – with over 400 species reported. Much of the bay is too deep to support traditional forms of plants and so these become a key producer of food for many species. The diversity and abundance is greatest in the spring and fall. 70% of the phytoplankton are from a group called dinoflagellates, small plants that have two hair-like flagella to orient, and even propel, themselves. Some of them produce the bioluminescence we sometimes see and others produce what we call red tide. During the summer, the populations change and the more abundant forms are diatoms. These lack the flagella of the dinoflagellates, but they do produce beautiful shells of silica.
There are at least 400 species of periphytic algae (attaching). Green algae are the most abundant and are most common in the local bayous. Cyanobacteria, which were once thought to be algae, are the most abundant in the marshes and periphytic diatoms dominate in the Sound.
And last, are the submergent and emergent grasses.
Submergent grasses are known as seagrasses. We have three species that like the higher saline waters. These are turtle, shoal, and widgeon grass. Turtle and shoal grass need the water to be at least 25 parts per thousand and are the dominate species in the lower portions of the bay. Widgeon grass can tolerate waters as low as 10 ppt and are found in the bayous and the upper portions of the bay system. Tapegrass only survives in freshwater and are found in the lower reaches of the rivers where they meet the bay.
Emergent grasses are what we call marsh grasses. Two species, Black Needlerush and Smooth Cordgrass dominate these. There are pockets of salt marshes found all over the bay system.
So how is the health of our aquatic life?
As you might expect, the diversity and abundance have declined over time, particularly since the 1950’s. One firsthand account of the change, describe a bayou that was clear, full of grass, and harbored shrimp the size of your hand. Then they were gone. He remembered the first change being water clarity. As development along our waterfront increased, the clarity decreased and the aquatic life declined. This has happened all over the bay system. Increase in run-off not only brought sand and sediment lowering water clarity, it also brought chemicals that both the plants and animals could not tolerate. Much of the point source pollution has been controlled but non-point pollution is still problematic. Fertilizers, pesticides and herbicides, oils and grease, and sediment have all been problematic. These can be reduced. Following recommendations from the Florida Friendly Landscaping website, (http://www.deactivated_site/.) property owners can alter how they are currently managing their landscape to reduce their impact on the aquatic life on the bay. Clean Marina (https://floridadep.gov/fco/clean-marina ) and Clean Boater (https://floridadep.gov/fco/cva/content/clean-boater-program ) recommendations can help reduce the impact from the boating community. Sustainable fishing practices, such as safe catch and release methods for unwanted fish and removing all monofilament are good practices. In 2019, Sea Grant will begin a program training local citizens how to monitor the diversity and abundance of aquatic species. If interested in volunteering, stay tuned.
Reference
Lewis, M.J., J.T. Kirschenfeld, T. Goodhart. 2016. Environmental Quality of the Pensacola Bay System: Retrospective Review for Future Resource Management and Rehabilitation. U.S. Environmental Protection Agency. Gulf Breeze FL. EPA/600/R-16/169.
by Rick O'Connor | May 4, 2018
Humans have inhabited the shores of Pensacola Bay for centuries. Impacts on the ecology have happened all along, but the major impacts have occurred in the latter half of the 20th century. There has been an increase in human population, an increase in development, a decrease in water clarity, a decrease in seagrasses, and a decrease in the abundance of some marine organisms – like horseshoe crabs, scallops, and some marine fishes. There has also been an increase in inorganic and organic compounds from stormwater run-off, fish kills, and health advisories due excessive nutrients and fecal bacteria in local waters.
A view of Pensacola Bay from Santa Rosa Island.
Photo: Rick O’Connor
Since the 1970’s, there have been efforts to help restore the health of the bay. Seagrasses have returned in some areas, fish kills have significantly reduced, and occasionally residents find scallops and horseshoe crabs – but there is still more to do. In this series of articles, I will present information provided in a recent publication (Lewis, et. al. 2016) and from citizen science monitoring. We will begin with an introduction to the bay itself.
The Pensacola Bay System is the fourth largest estuarine system in the state of Florida. The system includes Blackwater, Escambia, East, and Pensacola Bays. There are numerous smaller bayous, such as Indian, Mulat, and Hoffman, and three larger ones, which include Texar, Chico, and Grande. There are two lagoons that extend east and west of the pass. To the west is Big Lagoon and to the east is Santa Rosa Sound. The surface area of this bay system is about 144 mi2 and the coastline runs about 552 miles in length. There are four rivers that discharge into the system: the Escambia, Blackwater, Yellow, and East Rivers. The majority of watershed is in Alabama and covers about 7000 mi2. The mouth of the bay is located at the Pensacola Pass near Ft. Pickens and is 0.5 miles across. Depending on the source, the flush time for the entire bay has been reported between 18 and 200 days.
There are several ecosystems found within the bay system. Seagrasses are be found throughout the bay and bayous, but are more prevalent in Big Lagoon and Santa Rosa Sound. Oyster reefs have provided income for some in the East Bay area in the past, but production has declined in the last 50 years. Salt marshes are found throughout the bay as well, but the greatest acreage is in the Garcon area of Santa Rosa County. There are, of course, freshwater marshes near the mouths of the rivers with the largest being at the mouth of the Escambia River.
Members of the herring family are ones who are most often found during a fish kill triggered by hypoxia.
Photo: Madeline
Members of the drum family are one of the more common fishes found in the system and would include fish like the Spot and Atlantic Croaker. However, speckled trout, striped mullet, redfish, several species of flounder, have also been targets for local fishermen. Target fish include sardines, silversides, stingrays, pinfish, and killifish. Brown shrimp, oysters, and blue crab have historically provided a fishery for locals, but other invertebrates include several species of jellyfish, stone crabs, fiddler crabs, hermit crabs, grass shrimp, several species of snails, clams, bay squid, octopus, and even starfish. There is also a variety of benthic worms found within the sediments.
A finger of a salt marsh on Santa Rosa Island. The water here is saline, particularly during high tide. Photo: Rick O’Connor
There has been a decline in overall environmental quality since 1900 but, again, the biggest impacts have been between 1950 and 1970. Fish kills, a reduction in shrimp harvest, and hypoxia (a lack of dissolved oxygen) have all been problems.
In the articles to follow we will look deeper into specific environmental topics concerning the health of Pensacola Bay.
References
Lewis, M.J., J.T. Kirschenfeld, T. Goodhart. 2016. Environmental Quality of the Pensacola Bay System: Retrospective Review for Future Resource Management and Rehabilitation. U.S. Environmental Protection Agency. Gulf Breeze FL. EPA/600/R-16/169.
by Rick O'Connor | Apr 14, 2018
Shoal grass. One of the common seagrasses in Florida.
Photo: Leroy Creswell
For many, it really does not matter. But is there a difference? Yes… there is. Seagrass is what typically washes ashore on the Sound side – seaweed is what we typically see on the Gulf.
So what is the difference?
Seagrasses are actually grasses. They are true plants in the sense they have roots, stems, and leaves. They also produce flowers, but they are so small it is very hard to see them. Pollen and seed dispersal is via the currents. What the observer sees when snorkeling in seagrass meadows are the leaves – in this case called blades. The stems run horizontal beneath the sand, as many grasses in our lawns do. These are called rhizomes, and the roots extend from them. Turtle grass and Shoal grass are the two most common types we have here.
Seaweeds on the other hand, are not true plants because they lack roots, stems, and leaves. They are often called algae and must be submerged in water in order to absorb it. They are either float and drift in the currents, or can attach to hard objects on the seafloor using a structure called a holdfast. June grass and Sargassum are two common types that drift ashore.
So why don’t seagrasses grow in the Gulf?
Like all plants, seagrasses need sunlight. At least 25% of the sunlight reaching the surface must reach the bottom for them to photosynthesize. Near the shore, there is enough sunlight for seagrass, but they cannot tolerate the larger waves that our nearshore Gulf produces – thus they are restricted to the quieter waters of the Sound. We do have seagrasses growing in Big Lagoon, Old River, parts of Pensacola Bay, and even in some of the local bayous. This ecosystem is important to the overall health of our bay. It is known that 80-90% of the commercially and recreationally important finfish and shellfish require seagrasses, or salt marshes, for at least part of their life cycle – so they are important economically as well.
Seaweeds also need sunlight. In rocky areas, you can find them attached in sunlit waters. Much of our area is sand, so we do not see as many forms of seaweed as they do in the Keys or in California. However, we do have floating forms.
March is “Seagrass Awareness Month”. Many people provide opportunities to educate locals about our seagrasses and the issues they are facing. Excessive run-off from parking lots, ramps, homes, etc. – increase the turbidity and decrease the salinity of the water – both of which are detrimental to seagrass health. This run-off also contains pollutants that are problematic – particularly nutrients from fertilizers. The fertilizers trigger algal blooms which block sunlight and, in some cases, smoother the surface of the grass blades. Then there is prop scarring. The shallow waters where they live are also popular spots for boaters to visit. The propeller scarring leaves open tracts throughout the seagrass meadows and, unlike some grasses in our yards, can take years – even decades – to recover. There has been significant loss of seagrass all across the Gulf region, including Pensacola Bay. The loss of seagrass have also affected species such as bay scallop and horseshoe crabs. There are signs of recovery and we need to continue reducing our impact to keep this trend going. Florida Friendly Landscaping, Clean Boater practices, and Living Shorelines are some methods that can help. Contact your local County Extension Office to learn more about these programs.
