It’s Bat Week! Did You Know Bats Eat Insect Pests?

It’s Bat Week! Did You Know Bats Eat Insect Pests?

The week prior to Halloween is officially designated as National Bat Week. In honor of this event, it’s worth considering some of the benefits bats provide to us.

Did you know there is a species of bat that lives nowhere in the world but within our state? It’s called the Florida Bonneted Bat, and occurs in only about 12-15 counties in south and central FL. These bats are so mysterious that we’re currently not even sure exactly where they occur. They are so rare that they’re listed as a federally endangered species.

The Florida Bonneted Bat lives nowhere in the world but Florida. Photo credits: Merlin Tuttle.

These bats were named for their forward-leaning ears, which they can tilt forward to cover their eyes. With a wingspan of 20 inches, they are the largest bats east of the Mississippi River: only two U.S. species are larger than they are, and these both occur out west.

We have been investigating the diet of Florida Bonneted Bats. To do this, we captured bats in specialized nets, and then collected their scat (called guano). Next, we processed the scat in a laboratory using DNA metabarcoding to determine which insect species the bats had recently consumed.

We found that the bats eat several economically important insects, including the following:

  • fall armyworm (Spodoptera frugiperda)
  • lesser cornstalk borer (Elasmopalpus lignosellus)
  • tobacco hornworm (Manduca sexta)
  • black cutworm (Agrotis ipsilon)

These insects are pests of corn, cotton, peanut, soybean, sorghum, tobacco, tomato, potato, and many other crops.

Furthermore, the bats did not eat these insect pests infrequently. In fact, 86% of the samples we examined contained at least one pest species. On average, each sample contained three pest species! This tells us that Florida Bonneted Bats should be considered IPM (Integrated Pest Management) agents.

Currently, a new student has begun investigating the diets of bats more commonly found in northern Florida, southern Georgia, and southern Alabama. By the time Bat Week 2019 rolls around we’ll have details on which insect pests these bats could eat on your property.

If you’re interested in helping bats or incorporating them into your Integrated Pest Management efforts, consider creating roosts for them (places where the bats can sleep during the day). Bats roost not only in caves, but also in cavities in trees, in dead palm fronds, and in bat houses.

Florida’s Water Quality Woes

Florida’s Water Quality Woes

Being in the panhandle of Florida you may, or may not, have heard about the water quality issues hindering the southern part of the state. Water discharged from Lake Okeechobee is full of nutrients.  These nutrients are coming from agriculture, unmaintained septic tanks, and developed landscaping – among other things.  The discharges that head east lead to the Indian River Lagoon and other Intracoastal Waterways.  Those heading west, head towards the estuaries of Sarasota Bay and Charlotte Harbor.

 

A large bloom of blue-green algae (cyanobacteria) in south Florida waters.
Photo: NOAA

Those heading east have created large algal blooms of blue-green algae (cyanobacteria). The blooms are so thick the water has become a slime green color and, in some locations, difficult to wade.  Some of developed skin rashes from contacting this water.  These algal blooms block needed sunlight for seagrasses, slow water movement, and in the evenings – decrease needed dissolved oxygen.  When the algae die, they begin to decompose – thus lower the dissolved oxygen and triggering fish kills.  It is a mess – both environmentally and economically.

 

On the west coast, there are red tides. These naturally occurring events happen most years in southwest Florida.  They form offshore and vary in intensity from year to year.  Some years beachcombers and fishermen barely notice them, other years it is difficult for people to walk the beaches.  This year is one of the worst in recent memories.  The increase in intensity is believed to be triggered by the increase in nutrient-filled waters being discharged towards their area.

Dead fish line the beaches of Panama City during a red tide event in the past.
Photo: Randy Robinson

On both coasts, the economic impact has been huge and the quality of life for local residents has diminished. Many are pointing the finger at the federal government who, through the Army Corp of Engineers, controls flow in the lake.  Others are pointing the finger at shortsighted state government, who have not done enough to provide a reserve to discharge this water, not enforced nutrient loads being discharged by those entities mentioned above.  Either way, it is a big problem that has been coming for some time.

 

As bad as all of this is, how does this impact us here in the Florida panhandle?

 

Though we are not seeing the impacts central and south Florida are currently experiencing, we are not without our nutrient discharge issues. Most of Florida’s world-class springs are in our part of the state.  In recent years, the water within these springs have seen an increase in nutrients.  This clouds the water, changing the ecology of these systems and has already affected glass bottom boat tours at some of the classic springs.  There has also been a decline in water entering the springs due to excessive withdrawals from neighboring communities.  The increase in nutrients are generally from the same sources as those affecting south Florida.

 

Florida’s springs are world famous. They attracted native Americans and settlers; as well as tourists and locals today.
Photo: Erik Lovestrand

Though we are not seeing large algal blooms in our local estuaries, there are some problems. St. Joe Bay has experienced some algal blooms, and a red tide event, in recent years that has forced the state to shorten the scallop season there – this obviously hurts the local economy.  Due to stormwater runoff issues and septic tanks maintenance problems, health advisories are being issued due to high fecal bacteria loads in the water.  Some locations in the Pensacola area have levels high enough that advisories must be issued 30% of the time they are sampled – some as often as 40%.  Health advisories obviously keep tourists out of those waterways and hurt neighboring businesses as well as lower the quality of life for those living there.

 

Then of course, there is the Apalachicola River issue. Here, water that normally flows from Georgia into the river, and eventually to the bay, has been held back for water needs in Georgia.  This has changed flow and salinity within the bay, which has altered the ecology of the system, and has negatively impacted one of the more successful seafood industries in the state.  The entire community of Apalachicola has felt the impact from the decision to hold the water back.  Though the impacts may not be as dramatic as those of our cousins in south Florida, we do have our problems.

Bay Scallop Argopecten iradians
http://myfwc.com/fishing/saltwater/recreational/bay-scallops/

What can we do about it?

 

The quick answer is reduce our nutrient input.

 

The state has adopted Best Management Practices (BMPs) for farmers and ranchers to help them reduce their impact on ground water and surface water contamination from their lands. Many panhandle farmers and ranchers are already implementing these BMPs and others can.  We encourage them to participate.  Read more at Florida’s Rangeland Agriculture and the Environment: A Natural Partnership https://nwdistrict.ifas.ufl.edu/nat/2015/07/18/floridas-rangeland-agriculture-and-the-environment-a-natural-partnership/.  

 

As development continues to increase across the state, and in the panhandle, sewage infrastructure is having trouble keeping up. This forces developments to use septic tanks.  Many of these septic systems are placed in low-lying areas or in soils where they should not be.  Others still are not being maintained property.  All of this leads to septic leaks and nutrients entering local waterways.  We would encourage local communities to work with new developments to be on municipal sewer lines, and the conversion of septic to sewer in as many existing septic systems as possible.  Read more at Maintaining Your Septic Tank https://nwdistrict.ifas.ufl.edu/nat/2017/04/29/maintain-your-septic-system-to-save-money-and-reduce-water-pollution/.

 

And then there are the lawns. We all enjoy nice looking lawns.  However, many of the landscaping plans include designs that encourage plants that need to be watered and fertilized frequently as well as elevations that encourage runoff from our properties.  Following the BMPs of the Florida Friendly Landscaping ProgramTM can help reduce the impact your lawn has on the nutrient loads of neighboring waterways.  Read more at Florida Friendly Yards – https://nwdistrict.ifas.ufl.edu/nat/2018/06/08/restoring-the-health-of-pensacola-bay-what-can-you-do-to-help-a-florida-friendly-yard/.

 

For those who have boats, there is the Clean Boater Program. This program gives advice on how boaters can reduce their impacts on local waterways.  Read more at Clean Boaterhttps://floridadep.gov/fco/cva/content/clean-boater-program.

 

One last snippet, those who live along the waterways themselves. There is a living shoreline program.  The idea is return your shoreline to a more natural state (similar to the concept of Florida Friendly LandscapingTM).  Doing so will reduce erosion of your property, enhance local fisheries, as well as reduce the amount of nutrients reaching the waterways from surrounding land.  Installing a living shoreline will take some help from your local extension office.  The state actually owns the land below the mean high tide line and, thus, you will need permission (a permit) to do so.  Like the principals of a Florida Friendly Yard, there are specific plants you should use and they should be planted in a specific zone.  Again, your county extension office can help with this.  Read more at The Benefits of a Living Shoreline https://nwdistrict.ifas.ufl.edu/nat/2017/10/06/the-benefits-of-a-living-shoreline/.

 

Though we may not be experiencing the dramatic problems that our friends in south Florida are currently experiencing, we do have our own problems here in the panhandle – and there is plenty we can do to keep the problems from getting worse. Please consider some of them.  You can always contact your local county extension office for more information.

Restoring the Health of Pensacola Bay, What Can You Do to Help?  – Fecal Bacteria

Restoring the Health of Pensacola Bay, What Can You Do to Help? – Fecal Bacteria

Of all the issues facing our local estuaries, high levels of fecal bacteria is the one that hinders commercial and recreational use the most. When bacteria levels increase and health advisories are issued, people become leery of swimming, paddling, or consuming seafood from these waterways.

Closed due to bacteria.
Photo: Rick O’Connor

I have been following the fecal bacteria situation in the Pensacola Bay system for several decades. Cheryl Bunch (Florida Department of Environmental Protection) has done an excellent job monitoring and reporting the bacteria levels, along with other parameters, for years – she has been fantastic.

 

The organisms used for monitoring have changed, so comparing numbers now and 30 years ago is somewhat difficult – but those changes came with good reason.

 

Fecal bacteria are organisms found in the large intestine of birds and mammals. They assist with digestion and are not a real threat to our health.  Understanding that both birds and mammals in and near our estuaries must defecate, it is understandable that some levels of these bacteria are in the waterways.  However, when levels are high there is a concern there are high levels of waste in the water.  This waste can carry other organisms that can cause health problems for humans – such as hepatitis and cholera.  So fecal bacteria monitoring is used as a proxy for other potential harmful organisms.  No one wants to swim in sewage.

E. coli is a classic proxy for this type of monitoring and has been used for years. Recently it was found that saline water could kill some of the fecal bacteria – giving monitors’ low readings in estuarine systems – suggesting that there is little sewage in the water – when in fact there may be high levels of sewage undetected. They have found Enterococcus a better proxy for marine waters, particularly Enterococcus faecalis. Researchers have determined that a single sample of bay water should have more than 35 colonies of Enterococcus (ENT).  If they find 35 or more colonies – a second sample is taken.  If the counts are again high – a health advisory will be issued.

 

Over the last 30 years of monitoring FDEP’s reports on the Pensacola Bay area – there have been patterns. Most of the “hot spots” have been bayous and locations where rivers are discharging into an estuary.  In addition, the periods of high fecal counts correspond well with periods of high rainfall.  Locally, in the Pensacola Bay area, sampling has been reduced due to budget issues and some bodies of water are not sampled as often as others.  Today both FDEP and the Florida Department of Health (FDOH) monitor and post their data via the Healthy Beaches Program.  In this program, the sample stations are commonly used swimming areas – meaning some other locations are rarely, if ever, sampled. Based on these data, 30-40% of the samples from local bayous annually require a health advisory to be issued.

 

Health advisories can reduce interest in human related recreation activities, such as wakeboarding, paddling, or even fishing – and certainly impacts interest in swimming. Decades ago, swimming and skiing were very popular in local bayous.  Today it is rare to see anyone doing so – most are motoring through heading to open bodies of water to spend their day.  It may also be effecting property purchases.  I have been contacted more than once with the question “would you buy on a house on XXX Bayou?”

 

Several local waterways are listed as impaired, and one is a BMAP area, due to high levels of bacteria. A BMAP (Basin Management Action Plan – read more at the link below) is a state designated body of water that is impaired (for some reason) and is required to make annual improvements to reduce the problem.

The spherical cells of the “coccus” bacteria Enterococcus.
Photo: National Institute of Health

 

So What Can We Do to Reduce This Problem?

 

In the Pensacola area, both the city and county have made efforts to modify and improve stormwater problems. Baffle boxes in east Pensacola have helped to reduce the amount of runoff entering the bayous and bays, thus reducing the frequency health advisories are being issued.  That said, during heavy events the counts still increase – and rainfall seems to be increasing in the area in recent years.  We will continue to monitor the frequency of advisories and post these on Sea Grant Notes through the Escambia County extension office each week.

 

From our side of the story (you and me) – anything you can do to reduce runoff will certainly help. Florida Friendly Landscaping techniques are a good start (see article on FFL posted below).  Clean up after your pet, both in your yard and after walks – most people do… but not all.  Septic systems have been a point of concern.  If you have a septic system, maintain it (see article below on how).  If the opportunity presents itself, you can move from septic to a sewer system.  At many public places along the waterfront have signs asking everyone not to feed the birds.  Congregating birds equals congregating bird feces and this can be a health issue.

 

Local and state governments are working to reduce the stormwater impacts on our local estuaries – which trigger other problems as well as high bacteria counts. Local residents and businesses can do the same.

 

 

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.

 

BMAP

https://floridadep.gov/dear/water-quality-restoration/content/basin-management-action-plans-bmaps.

 

Florida Friendly Landscaping

Restoring the Health of Pensacola Bay, What You Can Do to Help? – Florida Friendly Landscaping

http://blogs.ifas.ufl.edu/escambiaco/2018/06/08/restoring-the-health-of-pensacola-bay-what-can-you-do-to-help-a-florida-friendly-yard/.

 

Septic Systems

Maintain Your Septic Tank System to Save Money and Reduce Water Pollution

https://nwdistrict.ifas.ufl.edu/nat/2017/04/29/maintain-your-septic-system-to-save-money-and-reduce-water-pollution/.

 

Septic Tanks: What You Should Do When a Flood Occurs

https://nwdistrict.ifas.ufl.edu/nat/2018/05/04/septic-systems-what-should-you-do-when-a-flood-occurs/.

Two Words, Six Americas: Finding common ground on climate change

Two Words, Six Americas: Finding common ground on climate change

Climate change. Those two simple words have the power to bring about a strong reaction in people. For many, the term is fraught with emotion—with worry, anger, and fear of the unknown. For others, these two words might elicit doubt or frustration. According to a multi-year, nationwide study conducted by George Mason and Yale Universities, as a country we react to the science of climate change along a spectrum of responses. On one end of the spectrum, people are “alarmed” (see a change in climate as a reality and taking action about it) and “concerned” (believe it is a serious issue but have not taken action). In the middle are those in different stages of understanding or awareness of climate issues, and characterized as “cautious”, “disengaged”, or “doubtful.” At the opposite end of the spectrum are the “dismissive”, which are that group of people who are actively opposed to action on climate change and may feel it is a conspiracy. These six categories were based on the responses of a large, in-depth survey conducted in 2008. Ten years later, researchers conducted the study again to see if attitudes had changed. Interestingly, they had—with the most noticeable shift out of the “disengaged” category, as people seemed to cast their lot with one side or the other.

2008/2009 Yale/George Mason Study Results 2018
18% Alarmed (+3) 21%
33% Concerned (-3) 30%
19% Cautious (+2) 21%
12% Disengaged (-5) 7%
11% Doubtful (+1) 12%
7% Dismissive (+2) 9%

Table 1. 10-year comparison of “Global Warming’s Six Americas” Study. Source: http://climatecommunication.yale.edu/about/projects/global-warmings-six-americas/

Looking at the data, respondents left the “disengaged” group and moved either towards doubtful and dismissive or towards the cautious category. It is likely that the 3% change out of “concerned” moved directly into “alarmed”, as extreme weather events and record temperatures over the last 10 years brought the impacts of a changing climate closer to home.

Data from a national study shows the level of agreement/disagreement on climate-based issues. Source: Yale/George Mason University

When the study is broken down by region, a minority of northwest Floridians believed human activities such as carbon emissions caused climate change. However ~65% of the same group believed climate change was happening (regardless of cause), and 80% responded that our country should fund research looking into renewable energy. The good news here is that while many of us do not agree on the cause of climate change, the majority of us agree on positive steps forward that may relieve some of its results.

For me, the take-home message of this study is that scientific understanding—on many issues, not just climate—is often along a spectrum based on exposure to research, personal interest/relevance, and cultural influences. When explaining any science-based concepts, it is important to know where your listener is coming from and start from there. It is unfortunate that we are in a time when many principles of science are taken as political positions and not products of unbiased scientific method. That being said, great thinkers from Galileo to Hawking have had their run-ins with popular opinion.

As the summer heat cooks on and hurricane season warms up, there will be more articles in the news about climate and its effects. When reading these, look at the source and their intent. Is this an opinion piece/blog with deeply emotional photos and stories meant to sway readers one way or the other? Or is it an agency page, reporting factual data? Time-tested agencies like the National Weather Service (NWS), National Oceanic and Atmospheric Administration (NOAA) and National Aeronautic and Space Administration (NASA) have been keeping historic records of climate data and satellite imagery of ice cover for decades. Use their information to inform yourself, no matter where you might fall upon the “six Americas” spectrum. Worldwide data for climate has been kept since 1880, and both NASA and NOAA climate data found:

  • 2016 was the hottest year globally on record
  • 2nd and 3rd hottest years on record were 2015 and 2014.
  • 16 of the 17 warmest years documented since 1880 have been since 2001

For more information on climate science, check out these resources: Intergovernmental Panel on Climate Change, NOAA Climate, and NASA Climate.

Summer is here!! Let’s learn about natural resources indoors!

Summer is here!! Let’s learn about natural resources indoors!

As the heat indicies rise, there a number of organizations that offer great learning experiences about our local Natural Resources!! While it is great to have the outdoor hands-on learning, the afternoon heat can feel suffocating. Here are a couple of nature centers that you can visit to get out of the heat.

 

Apalachicola National Estuarine Research Reserve is home to the Reserve’s Nature Center, located at 108 Island Drive, in East Point Florida. Inside the air-conditioned Nature Center are many interactive displays and tanks with live local animals. At one end of the center, there is a large mural that takes you from the upper-parts of the Apalachicola River to the Gulf of Mexico, There are many native animals identified on the mural.  There is an area with plenty of artifacts to keep the young and old naturalist busy.

 

The interactive cultural displays are really interesting and provide much information about the fishing industry that Apalachicola is known for throughout Florida.

The Reserve features a many trails that lead throughout the property and many to the water. The Apalachicola National Estuary Reserve is one of 29 National Estuarine Research Reserves in the U.S.  Each reserve is protected for “long-term research, water quality and habitat monitoring, education, and coastal stewardship.”

The Reserve is open to the public Tuesday through Saturday from 9 am until 4 pm, admission is free.

Photos provided by Chris VerlindeHeading to the west, near the town of Freeport Florida, you will find the E.O. Wilson Biophilia Nature Center. This amazing place will keep you and your family entertained for hours. If you plan to go, the center is only open to the public on Thursday and Friday during June and July from 9 am until 2 pm.  The cost is $8.00 for adults, $5.00 for children ages 3-12 and free for those 2 and under. The rest of the year, the staff are dedicated to teaching local students from surrounding school districts about biodiversity in Northwest Florida. As you enter the exhibit building there is a tribute to the famous naturalist E.O Wilson, whose work is the inspiration for center.  Dr. Wilson is dedicated to teaching others about the importance of conservation of biodiversity. He coined the term “biophilia” which means “the love of all living things.” The exhibit hall features many different displays on the cultural and natural resources in the area. The center features a reptile room, classrooms, an amphitheater, porches to enjoy your lunch and the “World of Wonder Exhibit.” which is a Science on a Sphere – a giant globe that utilizes technology to teach about the planets, our weather, and more.

Animals that can be found at the center include: birds of prey, bobcats, turtles and snakes, a red-cockaded woodpecker, a fox, and chickens. A short walk outside, you will find an authentic cracker house (with snakes!) and an organic garden.

The E.O. Wilson Biophilia center is a wonderful place to visit, check it out soon!!

Restoring the Health of Pensacola Bay, What Can You Do to Help?  – Bioaccumulation of Toxins

Restoring the Health of Pensacola Bay, What Can You Do to Help? – Bioaccumulation of Toxins

What is bioaccumulation of toxins?

 

Our bodies come in contact, and produce, toxins every day. The production of toxins can result during simple metabolism of food.  However, our bodies are designed with a system to rid us of these toxins.  Toxins are processed by our immune system and removed via our kidneys.  Some chemical compounds are structured in a way that they are not as easily removed, thus they accumulate in our bodies over time, often in fatty tissues, and sometimes they are toxic – this is bioaccumulation.

A view of Pensacola Bay from Santa Rosa Island.
Photo: Rick O’Connor

Biomagnification takes it a step further. In many cases, the concentrations of bioaccumulating toxic substances in the water may be in low enough concentrations to have little effect on human health.  They are ingested by small organisms in the environment, such as plankton or juvenile marine fish, and – again are at low concentrations.  However, they are accumulated in their tissues and as the next level of the food chain begin to consume them – they too accumulate the toxic compounds in their tissues.  Small fish consume large amounts of plankton and thus, large amounts of the toxins they have accumulated – increasing the concentration within their own tissues.  This continues up the food chain to a point where, in the larger predators, the concentrations of these toxins have increased enough that they now pose a threat to human health – this is biomagnification.

 

The presence, and amount, of any one bioaccumulating compound varies with species, their size, their age, their gender, their life stage, whether they are mobile or not, their diet, and whether the sample included the skin (which is lipid heavy and a common location for accumulated toxins). In the Pensacola Bay System, about 30 species of marine plants and animals have been analyzed for the presence of these accumulating compounds.

 

Species collected from Pensacola Bay that were analyzed for contaminants

Plants 3 species of seagrass

1 species of seaweed

Colonized algal periphyton

Invertebrates 4 species of freshwater mussels

Eastern oyster

1 species of brackish water clams

1 species of barnacle

Several species of shrimp

Blue crab

Oyster drill (snail)

Vertebrates 2 species of catfish

5 species of scaienids (drums, croakers, trout)

Bluegill

Bluefish

Several species of flounder

2 species of jacks

Largemouth bass

Sheepshead

Striped mullet

 

Trace Metal Accumulation

Much of what has been studied in terms of metal accumulation has come from shellfish – particularly eastern oysters. Ten different metals have been found in oysters with zinc being in the highest concentration and lead the lowest.  A 2005 study found that levels of arsenic, lead, and nickel collected from mussels collected at selected locations in the PBS were regionally high (meaning higher than other estuaries in the region).  Another study (2003) found that levels of 16 different metals in shellfish were three times higher in Bayou Chico than samples from East Bay.  A 1993 study found that organisms attached to pieces of treated wood in Santa Rosa Sound had elevated levels of metals.  However, another study (2008) found low concentrations of metals in five species of fish collected in Escambia Bay near the I-10 Bridge.

 

The bioaccumulation potential within plants is less understood than animals. That said – concentrations within seagrass were relatively low when compared to the sediments they were growing in and periphytic algae attached to them.

 

Total Mercury Concentrations (ng/g – dry weight) for Local Marine Organisms

Lewis and Chaney (2008)

Range (ng/g) Species
0-200 Sediments, seagrass, oysters
200 – 400 Periphytic algae
400 – 600 Mussels
600 – 800 Brackish clams, blue crabs
800 and higher Fish

 

The above table shows biomagnification.

 

Comparing trace metal concentrations between Pensacola Bay and other Regional Estuaries

(USEPA unpublished data)

Pensacola Bay, Escambia Bay, Escambia River, Bayou Texar, Bayou Chico, Bayou Grande, Santa Rosa Sound Grand Lagoon (Bay Co.), Mississippi Sound, Old River, Suwannee River, Withlacoochee River, Bay La Launch
Cadmium Higher in PBS; highest in Bayou’s Grande and Texar
Chromium Similar to other estuaries
Copper Slightly elevated in Bayou Chico and Escambia River; highest in Withlacoochee
Total Mercury Much higher in PBS; particularly in the bayous
Nickel Lower in PBS
Lead Higher in PBS; particularly in the bayous
Zinc Higher in PBS; particularly in the bayous

 

There are higher concentrations of trace metals in PBS and particularly in the bayous.

 

One of 39 stormwater drains into Bayou Texar.
Photo: Rick O’Connor

Non-Nutrient Organic Chemicals

These are compounds such as PCBs, DDT, and PAHs; many are actually families of multiple forms of compounds. Information on the bioaccumulation of these compounds in PBS is less common than those of trace metals.  However, this information is important since they have long half-lives and magnify within the food web.

 

That said – there are studies on these compounds that go back to the 1970’s. They looked at DDT, pesticides, and PAHs in oysters and croakers.  One study (1986-96) found DDT concentrations in oysters at 60 ppb or less.  A follow up study (2004-05) at those same locations found concentrations between 8-20 ppb.  One study (2008) found the order of accumulating non-nutrient organic compounds with PAHs as the highest and dieldrin at the lowest.  Downward trends were reported (2004-05) for many of these compounds including PAHs and PCBs.

 

Some of these compounds have entered the PBS via unlined ponds associated with on-land Superfund sites. Creosote and pentachlorophenol were stored for years in such ponds and have leached into area waters such as Bayou Chico and portions of upper Pensacola Bay.  A study (1987-88) found oyster drills sampled in these areas had concentrations 10x higher than reference sites in other parts of the PBS.

 

So what can we do about this?

 

The compounds that are there – are there. Many of these trace metals are heavy and sink into the sediments.  There occurrence within the food web has decreased over time and some have suggested the safest thing to do is to leave them where they are.  No doubt, any project requiring sediment movement requires much review and permitting.

To try to remove these compounds would be extremely expensive – hence the Superfund Program. So if we cannot clean the sediments without a lot of labor and money, can we reduce the amount that enters the bay today?

Many of these compounds come from industrial processing of products we really want or need. Reduction of the production of some will be difficult, but there is much industry can do to reduce the chance of those compounds reaching our estuaries – and they are doing this.  Point source pollution (direct discharge from an industry) has reduced significantly since the 1970’s.  Non-point sources (indirect discharge from you and I) is still a problem.  We can choose products that contain less (or none) of the compounds we discussed.  Following an IPM program for dealing with household and lawn pests (see article on Florida Friendly Yards – https://blogs.ifas.ufl.edu/escambiaco/2018/06/08/restoring-the-health-of-pensacola-bay-what-can-you-do-to-help-a-florida-friendly-yard/) can help a lot.  As can practices that reduce the amount of run-off reaching our bays.  Reducing your use of lawn watering, using rain barrels, or rain gardens, and planting living shorelines (all mentioned in the FFY article) can certainly help.

 

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.