Tag Archives: nutrients

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Lake Report: Leon County’s Cleanest and Dirtiest Lakes

Rob Diaz de Villegas WFSU-TV

Last week on our Water Moves EcoAdventure, we showed images of polluted waterways south of Tallahassee. We in this area benefit from a large amount of protected lands, which surround us with scenic views as well as protect many of our rivers and streams.  But Tallahassee itself is fairly urban; our paved roadways move pollutants into drainage ditches and sloughs instead of letting them sink into the ground to be filtered by the aquifer.  Some waterways are more affected than others.  Our lakes and rivers provide us with fresh fish and recreation; when they become compromised by algal blooms and other pollutants, they affect the health and economy of the communities around the resources.

With that in mind, I’ve compiled this list of lakes in the area, with data for each on cleanliness and safety concerns. We’re looking at three things:

  1. Nutrient load for each lake. We’ll link to a PDF of a report published by Leon County Public Works, which was compiled by Johnny Richardson (who we interviewed in the Water Moves video). I can’t link to the individual pages, but I will list them with the link back to the document if you’re interested in reading more.
  2. How safe is it to eat the fish in each lake? For this, I’m using a report created by the Florida Department of Health (DOH). This is also a PDF, and I’ll be referencing it in the same way.
  3. Toxic algal blooms. DOH has an Algal Bloom tracker which lists three locations in Leon County. During the rainy season, these blooms will get flushed, but the locations listed have had persistent nutrient problems and are still a risk to bloom when the weather dries.

North Leon: The Red Hills

Our largest lakes are located in the north of the county.  This is a sparsely populated area, protected to the north by over 300,000 acres of forested land held on hunting plantations.  Our recent Red Hills EcoAdventure explored some of these waterways and the land protecting them.  These are the cleanest lakes in Leon County.

Lake Iamonia (5,554 acres, the largest lake in Leon County)

Florida Fish & Wildlife's Michael Hill takes me out on Lake Iamonia near tall Timbers Research Station.

Florida Fish & Wildlife’s Michael Hill takes me out on Lake Iamonia near Tall Timbers Research Station.

Nutrients: The report we cite was issued by Leon County in 2011.  The report uses a measurement developed by FDEP, called a Trophic State Index, to determine the health of a waterbody.  It’s a formula that weighs nutrient levels (phosphorous, nitrogen, and chlorophyl a), with a score of 60 or higher denoting an impaired waterbody (40 for clearwater lakes, which are lower nutrient systems).  Lake Iamonia’s scores over the last few years are well blow that, averaging in the low 40s (chart on Page 64).

Fish Safety: According to the DOH Freshwater Fish Guide, this is a fairly healthy lake.  Florida lakes and rivers are considered to have low to medium mercury levels, so the guide puts limits on how much they recommend that an individual eats.  They recommend most fish caught in Iamonia be eaten no more than twice a week (page 16) for most species (slightly less for children and pregnant/ trying to get pregnant mothers).  This is as high as they go for any Florida waterbody.

Other Concerns: As we learned during the Red Hills Water EcoAdventure, the lake’s sinkhole was impounded in the 1930s.  While the dam has been removed, there is ecological damage that could take generations to fix.

Lake Miccosukee (6,257 acres.  It forms the northeast border of Leon County, but is located in Jefferson County)

Nutrients: It averages in the 50s on the TSI index (page 174-5); below the impairment level but higher than Iamonia due to an elevation of one particular nutrient, chlorophyl a.  This may be related to the dam constructed around its sinkhole in 1954.  It’s a story you see on many area lakes, playing out slightly differently on each.  Impounded lakes end up with floating islands of vegetation, tussocks, which block the sun and add organic material to the sediment.  This vegetation might be responsible for the elevated chlorophyl.

Fish Safety: The high amount of vegetation on the surface has reduced the amount of dissolved oxygen in the water, and so there aren’t a lot of fish in the lake.  Of the two species listed on the DOH document, it recommends no more than twice a week (page 18) for bluegill  and once a week for largemouth bass.  This is typical for bass throughout the document; some fish store more mercury in their fat cells.

Lake Jackson (4,000 acres)

Stormwater runoff in Elanor Klapp-Phipps Park.  This plot of land is adjacent to Lake Jackson, which is why it was purchased by the  Northwest Florida Water Management District.  Having protected land next to the lake reduced urban runoff into it.

Stormwater runoff in Elinor Klapp-Phipps Park. This plot of land is adjacent to Lake Jackson, which is why it was purchased by the Northwest Florida Water Management District. Having protected land next to the lake reduces urban runoff into it.

Nutrients: Over the course of the last few years, the color of the lake’s surface has clarified, so it technically qualifies as a clearwater lake with a lower TSI threshold.  As such, it would be considered an impaired lake, averaging in the 40s on the TSI index (page 95).  The report questions using the lower threshold, citing “the dynamic nature of the lake and the recent drought” (pages 95-96).  Part of the change in color is attributed to changes in stormwater management, which have reduced runoff to the lake.

Fish Safety: Bluegill & redear sunfish, twice a week.  Largemouth bass, once a week (page 16).

Lake Hall (182 acres, a part of the Lake Jackson Watershed)

Tall Timbers' Georgia Ackerman teaches me to stand up paddleboard on Lake Hall, as part of our Red Hills Water EcoAdventure.

Tall Timbers’ Georgia Ackerman teaches me to stand up paddleboard on Lake Hall, as part of our Red Hills Water EcoAdventure.

Nutrients: Lake Hall is one of the cleanest lakes in Leon County, averaging in the high 20s (page 91) on the TSI.  As a clearwater lake, it’s threshold for impairment is 40.  Lake Hall is partially located in Alfred B. Maclay Gardens State Park.  There are some restrictions on the use of motors on Lake Hall.

Fish Safety: Not listed.  The lake is fished pretty regularly, however.

Middle Leon County

Lake Lafayette 

Dead vegetation on the surface of Lower lake Lafayette.  The segmentation of the lake in the early twentieth century has affected its ability to "dry down."  Many Leon county lakes naturally empty every few years, and the plants and animals that live in the lake have adapted to and thrive in such conditions.  Impounding Lake Lafayette has caused floating mats of vegetation to form on its surface, disrupting the lake's ecology.  Clearing it is an involved and expensive process.

Dead vegetation on the surface of Lower Lake Lafayette. The segmentation of the lake in the early twentieth century has affected its ability to “dry down.” Many Leon county lakes naturally empty into sinkholes every few years, and the plants and animals that live in the lakes have adapted to and thrive in such conditions. Impounding Lake Lafayette has caused floating mats of vegetation to form on its surface, disrupting the lake’s ecology. Clearing the vegetation is an involved and expensive process.

As we learned on our Lafayette Heritage Trail Park EcoAdventure last year, the historical Lake Lafayette has been segmented into four smaller lakes by earthen dams.  As with other lakes in our area (Iamonia, Jackson, and Miccosukee), its sinkhole was separated to prevent the lake from draining.  The sinkhole is in Upper Lake Lafayette.  The other lakes are Piney Z. Lake, the Alford Arm, and Lower Lake Lafayette (which feeds the St. Marks River).  Impounding the lake has resulted in tussocks and accumulation of mucky sediment, as in the other lakes.

This lake is north of the Cody Escarpment and is considered a part of the Red Hills.  I classify it differently because of its more urban setting.

Nutrients :

  • Upper Lake Lafayette: Based on its color, its TSI index is 40.  It regularly exceeds that threshold, averaging about 50 TSI (page 132) and going into the 90s in 2005.  This part of the lake drains housing developments and is adjacent to the Walmart/ Costco shopping center on Mahan Drive.
  • Piney Z. Lake: Like Upper Lafayette, Piney Z.’s threshold is 40 TSI.  The lake regularly exceeds that, with scores typically between 50-70 TSI (page 136), and sometimes higher.  In late 2013, WFSU-FM reporter Lynn hatter reported on a toxic algal bloom on Piney Z.  The Department of Health’s Algal Bloom Tracking Tool still has a mark on the lake, though I don’t know how often that data gets updated.  The lake is bordered by Piney Z. Plantation housing development, whose newsletter advised residents on methods to reduce their nutrient contribution to the lake.
  • Alford Arm: Alford Arm drains the Miccosukee Greenway, the J.R. Alford Greenway, and the Welaunee Plantations.  It’s threshold is 60 TSI, and its average TSI is in the low 40s (page 140).
  • Lower Lake Lafayette: Its threshold is 60 TSI, and it has only exceeded that once in the last ten years, in 2004.  While its score came perilously close to 60 for a couple of years after that, since 2006 its TSI score has dropped into the low 40s/ upper 30s (page 146).

Fish Safety: Only Piney Z. is listed, recommending no more than two a week (page 27) for all species. I’m not sure if this data was collected before or after the toxic algal bloom.

Lake Talquin (6,963.  It is a larger lake than Iamonia, but it is an artificial lake created by a hydroelectric dam on the Ochlockonee River)

Nutrients: The lake averages in the low 50s on the TSI index, below its threshold of 60 (page 253).

Fish Safety: Two a week for all species except largemouth bass (page 22).

Lake Talquin is recognized as an outstanding body of water by the Florida Department of Environmental Protection.

The Bradford Chain of Lakes

The Bradford chain is comprised of three connected lakes: Bradford, Hiawatha, and Cascade.

The first time I ever paddled a canoe or kayak was in my mid-twenties, at the FSU Seminole Reservation on Lake Bradford.  Wanting to get my son Max out on the water at a younger age, I took him out there last year.

The first time I ever paddled a canoe or kayak was in my mid-twenties, at the FSU Seminole Reservation on Lake Bradford. Wanting to get my son Max out on the water at a younger age, I took him there last year.

Nutrients:

  • Lake Bradford: It averages in the 40s on the TSI index (page 191), which is below its threshold of 60.  It has risen since 2006; prior to then it had averaged in the 30s (the report theorizes that this may be due to runoff created  by Tropical Storm Faye in late 2008).  Lake Bradford sits between the FSU Seminole Reservation and the Tallahassee Museum, and drains the residential area between Orange Avenue and Capital Circle.
  • Lake Hiawatha: The lake averages in the 40s on the TSI index (page 194), below its threshold of 60.  While paddling the corridor between Lake Bradford and Lake Hiawatha, you pass the Florida panther enclosure in the Tallahassee Museum.
  • Lake Cascade: Lake Cascade Averages in the low 30s on the TSI index (page 197), well below its threshold of 60.  This lake is susceptible to drought.  The report lists gaps where water could not be collected due to low levels.

Fish Safety: Not listed.

South Leon

Lake Munson (255 acres)

The sad thing about Lake Munson is that it is really an attractive lake.  It is believed to have once been a cypress swamp, that had its water impounded in the 1800s.  It is still ringed by cypress trees.

The sad thing about Lake Munson is that it is really an attractive lake. It is believed to have once been a cypress swamp, that had its water impounded in the 1800s. It is still ringed by cypress trees.

Nutrients: “The lake has a history of severe water quality and ecologic problems including fish kills, algal blooms, floating aquatic vegetation, high nutrient and bacterial levels, low game fish productivity, sediment contamination, and depressed oxygen levels (Maristany and Bartel, 1989)” (page 206).  Lake Munson routinely exceeds 60 on the TSI index (page 208), though it will dip below the threshold seasonally, sometimes for over a year.  When I visited the lake earlier in the month, Johnny Richardson told me that the heavy rain we’ve gotten does help to flush the lake.  The DOH Algal Bloom tracking tool reports toxic blooms on both Lake Munson and on Munson Slough to the north of the lake (the slough also continues to the south through the Apalachicola National Forest, partially draining into Wakulla Springs).  The tool merely reports that there have been blooms recently.  The blooms had washed away when I visited, but Mr. Richardson expects them back in the summer.

Fish Safety: The DOH guide recommends no more than twice a week for all species but black crappie (page 19).  This is their recommendation based on mercury level.  There is a warning for PCBs (Polychlorinated biphenyl, an endocrine disruptor, page 35).  It recommends, based on PCB concerns in largemouth bass, no more than one meal a month.  That’s if you’re willing to put any amount of it in your body to begin with.

Additional Concerns: At several points over the last ten years, Lake Munson has exceeded the acceptable levels of fecal coliform (page 216).  Fecal coliform is caused by human or animal waste, and an excess could be due to septic tank failures or sewage overflows.

So that’s the good, the bad, and the ugly of our local lakes.  There is plenty of good recreation and fishing to be had, but it is helpful to know which bodies of water present potential health risks.  Most of the problems are preventable, if people are willing to make changes.  Some of the changes aren’t too much of a burden, and others have benefits beyond reducing personal pollution.  We’ll look at some of those in the coming weeks.

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Researchers and Oystermen Fighting for Apalachicola Bay

Last week, Hanna Garland showed us how the Hughes/ Kimbro Lab adapted their techniques for underwater research in Apalachicola Bay. She talked about their difficulties with the weather, and as you can see in the video above, it was difficult for their oysterman collaborator (as it is for Apalachicola oystermen these days) to find enough healthy adult oysters to run the experiment. Below, David Kimbro looks back at the big Biogeographic Oyster study and what it has taught them about how oyster reefs work, and how they’ve been able to take that knowledge and apply it to the oyster fishery crisis.
Dr. David Kimbro Northeastern University/ FSU Coastal & Marine Lab

IGOR chip_ predators_NCE 150IGOR chip- biogeographic 150IGOR chip- employment 150

Does our study of fear matter for problems like the Apalachicola Bay oyster fishery crash? Absolutely.

Bear with me for a few sentences…

I like to cook. My first real attempt was a chicken piccata and it was a disaster. After ripping off the recipe from my brother (good cook), I quickly realized that the complexity of the recipe was beyond me. To save time and fuss, I rationalized that the ordering of ingredients etc. didn’t matter because it was all going into the same dish. Well, my chicken piccata stunk and I definitely didn’t impress my dinner date.

Way back in 2010, David paddles to one of the St. Augustine sites used in the lab's first tile experiment. Since then they have done two spat tile experiments and two cage experiments ranging from Florida to North Carolina.

2010: David paddles to a St. Augustine oyster reef during his lab's first tile experiment. Since then they've done two spat tile experiments and two cage experiments ranging from Florida to North Carolina.

Around this same time… long, long ago, a bunch of friends and I were also working on a basic science recipe for understanding how oyster reefs work and it only contained a few ingredients: predatory fish frighten crabs and this fear protects oysters….a beautiful trophic cascade! But years later, we figured the recipe was too simple. So, we overhauled the recipe with many more ingredients and set about to test it from North Carolina to Florida with the scientific method.

Now that we finally digested a lot of data from our very big experiment (a.k.a. Cage Experiment 1.0), I can confidently say that the fear of being eaten does some crazy things to oyster reefs. And even though most of the ingredients were the same, those crazy things differed from NC to Florida. While our final recipe isn’t perfect, we now have a better understanding of oyster reefs and that the recipe definitely has many more ingredients.

For instance,

  1. Mud crab hearing testThe fear of being eaten has a sound component to it. Previously, we thought fear was transmitted only chemically, but now we know that crabs can hear. This is huge!
  2. Oyster filtration and oyster pooping can affect the amount of excess nutrients in our coastal environment. Our collaborator (M. Piehler, UNC-CH) showed that in some places, this can remove excess nutrients and that this services makes an acre of oyster reef worth 3,000 every year in terms of how much it would cost a waste water treatment facility to do the same job.
  3. In a few months, I hope to update you on how sharks, catfish, drum, and blue crabs fit into the recipe.

In addition to uncovering some new ingredients, our pursuit of this basic science matters because it allowed us to figure out what methods and experiments work as well as what things don’t  (Watch how they reinvented one of their most depended upon tools: The spat tile experiment). In short, the fruits of this basic science project can now be shunted into applied science and the development of interventions to improve the Apalachicola Bay oyster fishery.

But given that the lack of oyster shell in the bay is clearly the problem and that re-shelling the bay would bring the oysters back, why do we need to conduct the research? Well, then again it could be the lack of fresh water coming down the Apalachicola River and/or the lack of nutrients that come with that fresh water. Oh, don’t forget about the conchs that are eating away at oyster reefs in St. Augustine, Florida and may be doing the same to those in Apalachicola.

Shawn Hartsfield tonging for oysters to be used in the Apalachicola Bay experimentLike the chicken piccata recipe, Apalachicola Bay is awesome, but it’s complicated. Clearly, there are lots of things that could be in play. But if we don’t understand how they are all linked, then we may waste a lot of effort because fixing the most important part with Ingredient A may not work without simultaneously fixing another part with Ingredient B. Even worse, maybe Ingredient B must come first!  Only through detailed monitoring and experiments will we figure out how all of the ingredients fit together.

Luckily, my brother shared the fruits of his basic culinary experiments so that I could quickly solve my applied problem: cooking a good dinner for the second date. Similarly, it’s great that we received funding from NSF to conduct our biogeographic oyster study, because now we can quickly apply the same methods and personnel to help figure out what’s ailing the Apalachicola Bay oyster fishery. Basic and Applied science, Yin and Yang.

–David

What’s next?

David’s colleague, Dr. Randall Hughes, takes us through another ecosystem that has been affected by drought in recent years, the coastal salt marsh.  As severe droughts become a normal occurrence, coastal ecosystems like marshes or the oyster reefs of Apalachicola Bay stand to take a beating.  Randall is looking at what makes a marsh stronger in the face of drought and other disturbances.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

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What’s the deal with nutrients and oysters?

As David & co. start their new research on the Apalachicola oyster fishery crisis, He and Randall (and their colleagues in Georgia and North Carolina) are starting to wrap up the NSF funded oyster study that we have been following over the last couple of years.  Over the next few weeks, we’ll take a look back at that research through a series of videos.  We’ll cover some oyster basics (how does an animal with no brain behave?), explore David and Randall’s ideas on the role of fear on the oyster reef (what makes a mud crab too afraid to eat an oyster?), and see the day-to-day problem solving and ingenuity it takes to complete a major study.  As these videos are released, we’ll also keep tabs on the work being done in Apalachicola Bay, in which many of the same methods will be used.
Dr. David Kimbro FSU Coastal & Marine Lab

After all, nutrients are basically plant food and oysters are animals.  And how could too few nutrients coming down with the trickling flow of the Apalachicola River possibly explain the record low number of Apalachicola oysters?

This is the perfect time to use the favorite idiom of my former mentor Dr. Ted, “The long and the short of it is….”

The short of it: Plants love nutrients and sunlight as much as I like pizza and beer. But unlike my favorite foods, these plant goodies make plants grow fast and strong. This works out well for us because we all need nutrients for basic body functioning, and because we get them by eating plants and/or by the eating animals that previously consumed plants.

For our filter-feeding bivalve brethren, they get nutrients and energy by eating plant-like cells (phytoplankton) that float in the water. So, it is possible that the trickling flow of the Apalachicola River is bringing too few nutrients to support the size of the pizza buffet to which the Apalachicola oysters are accustomed. But this idea has yet to be tested.

Hanna Garland and Stephanie Buhler harvest oysters from sample reefs in Apalachicola Bay.

The long of it: Long before the flow of the Apalachicola River slowed to a trickle, there weren’t a lot of nutrients. That’s why the numbers of humans used to be so low: too few nutrients meant too few plants and other animals for us to eat.

How could this possibly be the case given that 78% of the air we breathe is made up of a very important plant nutrient, nitrogen? And there is a lot of air out there!

Well, only a precious few plants exist that can deal with the nitrogen in our air and these are called nitrogen-fixers. Think of these as single-lane, windy, and bumpy dirt roads. In order to help create a plant buffet for all of us animals, a lot of atmospheric nitrogen (bio-unavailable) has to travel down this very slow road that the n-fixers maintain. As a result, it naturally takes a long time for the land to become fertile enough for a large buffet. And, it only takes a couple of crop plantings to wipe out this whole supply of bio-available nitrogen that took so long to accumulate.

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Sea birds on a guano island off the coast of Peru. (zand.net)

Turns out that the ancient Inca civilization around Peru was not only lucky, but they were also pretty darn smart. Lucky, because they lived next to coastal islands that were basically big piles of bird poop, which is very rich in bio-available nitrogen. I’m talking thousands of years of pooping on the same spot! Smart, because they somehow figured out that spreading this on their fields by-passed that slow n-fixing road and allowed them to grow lots of food. Once Columbus tied the world together, lots of bird poop was shipped back to European farms for the same reason. That’s when the European population of humans sky-rocketed.

Turns out that humans in general are pretty smart. Through time, some chemists figured out how to create artificial bird poop, which we now cheaply dump a lot of on our farming land. So, in these modern days, we are very, very rich in bio-available nutrients.

Where am I going with the long of it? Well, on the one hand, these nutrients wash off into rivers and then float down into estuaries. This is how the phytoplankton that oysters eat can benefit from our solution to the slow n-fixing road. In turn, oysters thrive on this big phytoplankton buffet.

Slide by Ashley R. Smyth, Piehler Lab, UNC Chapel Hill Institute of Marine Sciences.

But, on the other hand, too much of these nutrients flowing down into our estuaries can create big problems. Every year, tons of nutrient-rich water makes it way down the Mississippi and into the shallow Gulf of Mexico waters. There, this stuff fuels one big time buffet of phytoplankton, which goes unconsumed. Once these guys live their short lives, they sink to the bottom and are broken down by bacteria. All this bacterial activity decreases the oxygen of water and in turn gives us the infamous dead zone. Because nutrient-rich run-off continues to increase every year, so too does the dead zone.

I’ll close with the thought that oysters themselves may help keep the phytoplankton buffet from getting out of control by acting like anti-nitrogen fixers. In other words, they may help convert an excess of useable nitrogen back into bio-unavailable nitrogen. While this might not have been a great thing to have in low nutrient situations, we currently live in a nutrient-rich era. What’s even cooler is that it all has to do with poop again! But this time, we are talking oyster poop.

Oyster Summit 6

Dr. Mike Piehler, presenting to his collaborators Dr. Jeb Byers (Right), Dr. Jon Grabowski (reclined on couch), Dr. Randall Hughes and Dr. David Kimbro (out of frame). These five researchers have worked on oyster reef ecology since their time at the University of North Carolina. Three years ago, the National Science Foundation funded research into their ideas about predators and fear on oyster reefs.

So does this really happen? Yes. Check out an earlier post for the details. But we don’t fully understand it and that’s why it is a major focus of our research. Our collaborator, Dr. Michael Piehler of UNC-Chapel Hill, is leading this portion of our research project. Read more of Dr. Piehler’s work on this topic here.

So, hopefully this post explains why the relationship between nutrients and oysters is not so simple. But it sure is interesting and a worthy thing to keep studying!

Cheers,
David

In the Grass, On the Reef is funded by the National Science Foundation.

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