Well… It’s Better
When I joined Florida Sea Grant in 2012 my advisory committee told me water quality was one of their major concerns. Makes sense really. Some members were from the tourism and boating industry. Some were from commercial and recreational fishing. Others were homeowners. ALL had concerns. ALL depended on clean water for the success of their business and for the quality of their own lives. It is a big concern.
Since that time, we have been training volunteers to monitor nutrients and salinity. We just recently added harmful algae monitoring and we report fecal bacteria data collect by the Department of Health. All to (a) get people out there so they can see what is happening themselves, and (b) provide information we share with the members of the community.
Lakewatch is a program where volunteers use their boats to monitor nutrients at three locations in a particular waterway within the bay system. Excessive nitrogen and phosphorus can lead to agal blooms, which in themselves can be a problem, just ask the folks in south Florida. But when these organisms die, they form dense mats of organic matter that sink and decay. The decaying process is oxygen demanding and the dissolved oxygen in the system decreases to levels where fish kills can happen. Many may remember the large fish kills our bayous experienced in the 1960s and 1970s.
Their samples are analyzed by the Lakewatch lab in Gainesville for total nitrogen, total phosphorus, and total chlorophyll a (which is a proxy for phytoplankton in the water column – algae). The volunteers also measure the water clarity using a secchi disk. Water clarity decreases with increase algal blooms and this can be a problem for submerged seagrasses. The lab provides us with the salinity when they analyze the samples.
Below is a table of data since sampling began in 2007. However, some locations are JUST getting started.
Table 1. Nutrients in the Pensacola Bay Area
All values are the geometric means.
|Body of Water||Total Phosphorus (µg/L)||Total Nitrogen (µg/L)||Total Chlorophyll a (µg/L)||Water Clarity (Feet)||Salinity (parts per thousand)|
|Lower Perdido Bay|
Pensacola Bay was only sampled for one year (2019-2020). These three stations extend from the near the mouth of Bayou Texar, along the east side of the 3-Mile Bridge to the middle where the “hill” is in the bridge. This site is open and in need a volunteer. If interested, contact me. You will notice as you glance at the data table there is very little information on this location. The data provided in this table is the geometric means over the period of monitoring. Only data from station #2 was enough to report on and the values for nutrients are on the lower side. The water clarity is one of the better locations at 7.3 feet and there is insufficient data to report on the salinity.
Again, this site was not monitored for long and there is not enough to see short- or long-term trends here. But based on the little information provided, there does not appear to be nutrient issue here.
Bayou Texar has been monitored the longest in this Lakewatch program. One volunteer monitored from 2000-2002 before stopping. A second volunteer began in 2007 and monitored until 2013 when a third volunteer took on these sites. There is a current need for a new volunteer to continue monitoring this location beginning in 2023 – contact me if interested. The Lakewatch data is provided in two sections, one covering the 2000-2002 monitoring period, and the other the 2007-present. The data provided in this report are those collected between 2007-present. The sample stations run north to south with #3 being closest to the mouth near Cervantes Bridge.
A quick glance at the data shows significantly high nitrogen values, particularly at station #1 (near the 12th Avenue Bridge). Most bodies of water monitored in this project have nitrogen values running between 200-400 µg/L (Bayou Chico being an exception – more on that next). The total nitrogen in Bayou Texar runs between 600-800 µg/L – MUCH higher than the others. Though the total nitrogen is higher, the total phosphorus and chlorophyll numbers are not much above other locations (again, Bayou Chico is an exception). Water clarity, between 3-4 feet, is low for most locations. The salinity is also lower than most.
Since 2007 there have been significant improvements in total phosphorus at stations #2 and #3 – meaning improvements as you go from the 12th Avenue Bridge to the Cervantes Street Bridge. Water clarity has significantly improved at all locations. This is all good news. However, the total nitrogen numbers have not changed significantly over that time and are much higher than other bodies of water sampled. When you look at the number of health advisories issued for Bayou Texar it tends to be around 30% of the samples collected. Much better than Bayou Chico but higher than other bodies of water monitored by the Health Department.
Bayou Texar does have a total nitrogen problem and the closer you get to the 12th Avenue Bridge, the worse it becomes. Sources of nitrogen can come from leaf litter, fertilizers, animal waste, and leaky septic tanks, or sanitary sewage overflows. Identifing which source is the problem will be difficult. Some suggest the issues may be coming further upstream in Carpenters Creek. It is recommended that local residents and businesses along the creek and bayou use some of the management practices listed at the end of this report to help reduce this problem. There is a large effort currently to try and improve conditions in and around Carpenters Creek. Many of the properties along the bayou might consider the BMPs listed at the end of the report. Based on the chlorophyll data, Bayou Texar is border lined eutrophic (excessive nutrients). Reduction of nitrogen would help.
There are records of seagrass growing in Bayou Texar as well as active ospreys, dolphins, and even manatee sightings.
Bayou Chico has been sampled since 2014. The stations run from west to east with station 3 being the closest to the mouth of the bayou (near the bridge). As you glance across the numbers you will notice the nutrient data is slightly higher than the other bodies of water. The other bodies of water have total phosphorus between 10-20 µg/L. However, Bayou Chico has the highest values running between 20-30 µg/L. Other than Bayou Texar, the total nitrogen values are between 200-400 µg/L. Though lower than Bayou Texar, Bayou Chico is high running between 300-600 µg/L. The same is true for the third nutrient parameter chlorophyll. At most locations, excluding again Bayou Texar, the chlorophyll values are less than 5 µg/L. Bayou Chico has the highest values running between 8-16 µg/L. Along with Bayou Texar it has the lowest water clarity between 3-4 feet and has the freshest water in our sample locations with salinities running at 7 ppt.
Though most parameters have improved slightly since 2014, there have been no significant changes in water quality. There has been a slight increase in nitrogen at two stations – but again, not significant.
These values do classify Bayou Chico as eutrophic (nutrient excessive). The lower water clarity and salinity suggest more freshwater input – possibly from stormwater runoff. The low water clarity could be from small algal blooms but could also be attributed to shore-based sediments entering the system via stormwater runoff. These excessive nutrients could be linked to the excessive health advisories issued here due to fecal bacteria entering the waters. Based on data from the Department of Health, over the years Bayou Chico has required a health advisory be issued 50-60% of the time they sampled – significantly more than the other bodies of water monitored. Since 2010, this is the only body of water currently being monitored that has experienced a large fish kill – though this fish kill was attributed excessive warm water (which, like algal blooms, is oxygen demanding). It is a body of water that has seen problems for decades and is the only body of water in our area that requires a state Basin Area Management Plan (BMAP).
There are records of seagrass growing in Bayou Chico – and this is good news. There are also reports of ospreys, dolphins, and manatee sightings here as well. The state has deployed oyster reefs to help remove nutrients. There is an invasive species present (giant salvinia – Salvinia molesta) that is of concern. The state is currently managing this plant. It prefers high nutrient, low energy (calm) freshwater water. The salinities of the other bayous may be too high for this plant, but we are trying to education residents about the situation and help monitor/remove it if it appears. You can contact the county extension office for more information on this plant if interested.
Bayou Grande has been monitored since 2012. The stations also run west to east with station #3 closest to the mouth near NAS main side bridge. As you glance across the numbers you will notice values at, or below, average for the areas sampled. Total phosphorus runs close to 15 µg/L. Total nitrogen values run close to 300 µg/L. Total chlorophylls are some of the lowest running close to 4 µg/L. Water clarity is the clearest of all three of the bayous running between 4.5-6 feet and is also the saltiest with salinities running around 15 ppt.
All though all parameters have shown improvement in water quality since 2012, most are not significant improvements. The one exception is water clarity at station #1 – it has shown significant improvement during this time.
In general Bayou Grande is in the best shape of the three bayous and compares well with the open bay stations being monitored. It is classified as mesotrophic – meaning nutrients are middle range (where you expect an estuary to be). The health advisory reports are usually between 20-30% of the samples taken and fish kills have not occurred here since we began monitoring. There have been improvements on septic to sewage conversions in these communities, as well as efforts to build living shorelines (which can help reduce nutrient runoff to the bayou coming directly from properties in lieu of storm drainpipes). It is also a larger bayou (hence its name) with less development along the southern shoreline. There are more efforts planned to try and improve sewage issues and in planting living shorelines using filter feeding oysters. Residents along Bayou Grande could also incorporate Florida Friendly Landscaping principals to help reduce nutrients further as well as incorporate clean boating practices. Information on these programs can be found at your county extension office.
Big Lagoon has only been monitored since 2020. Thus, there are gaps in the data table where there are insufficient data to calculate a geometric mean. The sample stations run from east to west with #1 being closest to Ft. McRee and the mouth of the Pensacola Bay system itself. Glancing at the data where a geometric mean was able to be determined you will see that nutrient values are some of the lowest in the bay area. The total phosphorus runs between 12-13 µg/L, total nitrogen between 200-250 µg/L, and the total chlorophyll between 2-3 µg/L. The water clarity data are the clearest in the bay area, running from 9-10 feet. The salinity is interesting. At station #1 (near Ft. McRee) the geometric mean for salinity is 18 ppt, but at station #3 (near Big Lagoon State Park) it is only 8 ppt.
Since sampling only began two years ago, it has not been long enough to determine any long-term trends.
The chlorophyll numbers are actually low enough to classify Big Lagoon as oligotrophic (nutrient poor). This is unusual for an estuary, which are typically bodies of water with moderate amounts of nutrients due to natural runoff. But remember (a) Big Lagoon does not have a lot of natural runoff and (b) we have only been collecting samples there for two years.
The interesting thing about the salinity is how low it is. Station #3 (near Ft. McRee) is 18 ppt and being so close to the mouth of Pensacola Bay, and the Gulf of Mexico, you would expect this to be higher – maybe between 25-30 ppt. The fact that there are thick beds of turtle grass (Thalassia testdidnium) suggest that the actual mean is probably higher than the 18 ppt reported here. The opposite side of Big Lagoon is interesting as well. Station #3 reports a geometric mean of 8 ppt. This is equivalent to the upper end of Bayou Texar (near the 12th Avenue Bridge) and most of Bayou Chico. This too seems very low for this body of water. The Department of Health samples for fecal bacteria near Big Lagoon State Park and it does, at times, get high enough (> 70 colonies/100ml) for a high bacteria reading. DOH usually takes a second sample to confirm the reading and most often the second reading is lower, and a moderate classification is given for that week. That said health advisories have been given in this region, albeit less than 10% of the samples taken. All of this suggest that there may be some runoff issues at the west end of the Lagoon. Obviously more sampling is needed.
This body of water does support plenty of seagrass, ospreys, dolphins, and an increase in manatee reports. There are diamondback terrapins and horseshoe crabs both reported here as well. But it was also a location where bay scallops once thrived and no longer do. Scallop searches have been ongoing here for six years and only one live animal has been found. There are several possible reasons for their decline, decrease in salinity maybe one of them. Monitoring will continue. It is also a location where the state has measured a decline in seagrass – also concerning. Sea Grant is currently partnering with the University of West Florida to monitor both seagrass abundance and water quality within Big Lagoon.
Lower Perdido Bay has been monitored since 2014. The three stations run from south to north. Station #1 is near Innerarity Point and station #3 is near Tarkiln Bayou. Glancing across the numbers of the lower Perdido you will see that they are similar to most of the other bodies of water being monitored. The total phosphorus is 15 µg/L. The total nitrogen is between 320-330 µg/L. And the total chlorophyll is 5 µg/L classifying this area of Perdido Bay as mesotrophic. Being an open bay, the water clarity is higher, running between 5-6 feet, and the salinity is reported at 15 ppt. As with Big Lagoon, the salinity seems lower than one would expect but historic records suggest that Perdido Bay in general may have been lower than most other open bays. Historically the mouth of the bayou open and closed frequently giving the Spanish the reason to name it Perdido (“Lost Bay”). This closer may have made it more of a freshwater system – similar to the dune lakes of Walton County and the historic Choctawhatchee Bay – and may play a role in the lower salinity of Big Lagoon.
The trends over time show that most parameters have improved but not significantly. The one exception is total nitrogen. The total nitrogen in lower Perdido Bay has significantly decreased over the period Lakewatch has been monitoring – and this is good news.
Perdido Bay has had a history of poor water quality, but this is due more to industrial compounds being released through the tributary creeks. These compounds did cause other problems, including some species of fish altering sex, and whether these are still an issue cannot be determined by these data – this project is monitoring for nutrients. The nutrient driven algal blooms and fish kills found in the bayous 50 years ago were not as common in this body of water and these data suggest that the system is mesotrophic as most estuaries are. As with most of the other bodies of water, ospreys, dolphins, and manatees have all been recorded here. Seagrasses are present but being a less saline system than Big Lagoon and Santa Rosa Sound, the species composition is different and abundance is less. There have been efforts to survey for bay scallops in the lower portions of Pensacola Bay, but no efforts have been made in the lower Perdido due to salinities currently, and historically, not being high enough. Again, the lower salinity is thought to be more natural than from heavy development and urban runoff.
In summary, these data suggest that the nutrient problems area waterways experienced in 1960s and 1970s have improved. Algal blooms and fish kills are no longer common. But there still could be dissolved oxygen (DO) issues at the bottom of our bays and bayous that reduce biodiversity. This is not monitored by Lakewatch and we are not aware of any long term monitoring of DO to know how things have changed in the last 50 years.
Anecdotal reports suggest the coverage of seagrasses in these systems are improving. Though there are seagrasses in Big Lagoon, some reports suggest there has been a decline in recent decades. There is a current citizen science project entitled Eyes on Seagrass where Sea Grant and the University of West Florida train volunteers to monitor both coverage and species composition. Data from this project will presented in a separate report later in the year. There are also separate citizen science efforts monitoring the presence of bay scallops, horseshoe crabs, and diamondback terrapins in the bay area. Horseshoe crabs are being encountered more often, as are terrapins, but bay scallops seem to still be missing. As with the seagrass monitoring, these reports will be coming later this year.
There are still concerns with both Bayou Chico and Bayou Texar – these being the only two nutrient eutrophic systems in this monitoring project (based on chlorophyll data). Efforts to better understand the sources of nutrients, and enact better management practices, should be considered for these waterways. Things such as reducing fertilizer use, mitigating fertilizer runoff with living shorelines, converting from septic to sewers, better maintenance of septic systems, and reduction of sanitary sewage overflows are all actions that citizens can take now to help improve these waterways. For information on how to do these, contact your county extension office and we will be glad to assist.
- Reducing Health Advisories in Our Coastal Waters; Part 4 Maintaining Your Sewage System - March 10, 2023
- Reducing Health Advisories in Our Coastal Waters; Part 3 How Sewage Treatment Works - March 3, 2023
- NISAW 2023: Final Wrap Up - February 25, 2023