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DeLeon Springs, Volusia County, revisited, May 2017

DeLeon Springs is a wide spring that flows through a wide run into Spring Garden Lake, into Lake Woodruff, and finally into Lake Dexter before it flows into the St. Johns River.  More than a century ago, a dam and a wall were constructed around the headspring to create a large pool for swimming (the spring was developed as a fountain of youth spa, http://www.floridasprings.org/visit/map/deleonsprings/).  Although I don’t know that it has made anyone immortal, the spring is still a popular spot for swimming and for eating pancakes.

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The pool at the headspring of DeLeon Springs.

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Water rushing over rocks piled against the dam in a natural-looking spillway.

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The wide run of DeLeon Springs.  The shorter trees in the center of the photo indicate where the run curves around to join Spring Garden Lake.

Although the pool and run of DeLeon Springs are large, the discharge of the spring actually is fairly low (27 cfs, http://www.sjrwmd.com/springs/poncedeleon.html).  The conductivity of the spring is moderate (770 micromhos/cm), about 1/3 of the conductivity of Volusia Blue Spring and about 1/7 of the conductivity of Salt Spring, but still higher than any of the springs on the Suwannee or the Santa Fe Rivers.  Nutrient concentrations are moderate (nitrate = 0.8 mg/L, phosphate = 0.05 mg/L).  Not surprisingly given the abundant algae, the oxygen concentrations that I measured in the run were high (7.5 mg/L), although the oxygen concentration above the dam is quite low (less than 1 mg/L).

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Green water in DeLeon Springs run.  The camera sometimes autoadjusts the colors in deceiving ways, but the water really was this green.

DeLeon Springs was the very first spring that I visited in January 2017.  Because it is so close to me, I decided to try out my gear there.  It was an utter failure.  I tried to trap fish with a trash can and only managed to catch a few mosquitofish as I stumbled around in the cypress knees and muck.  There was so much suspended material in the water and sediment on the bottom that fluffed up at the slightest disturbance that poor water clarity precluded seeing much of anything.  Also, I was naive to video so my camera placement was less than perfect.

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My original rig, with kayak towing bottomless trash can in a rubber raft.  A woman saw me and told her child that I was a very nice person for picking up trash.  I got a lot lighter and more maneuverable when I dumped the raft and trash can.

I returned to DeLeon Springs in May for my last survey.  The water clarity still was poor, but I got much better at camera placement and I was able to get useable, although not great, data.  I am quite sure that both my counts and species richness numbers were low below the dam.

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This ramp was the only place where I could place the camera in the headspring as the dam makes it quite deep.  The mosquitofish (Gambusia holbrooki) are a little hard to see in this still photo, but there are a lot of them (much easier to see on the video).

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Two bluegill sunfish (Lepomis macrochirus) and a spotted sunfish (Lepomis punctatus) in the run below the dam.  The water clarity made fish counting a challenge, but most were recognizable.

In the end, the species richness, or the total number of species, and the total count of fish on video for DeLeon Springs were not as low as I expected it to be given how murky the water was.  Both the species richness and the total count were equal to the average for the St. Johns River springs (16 species and 26 individuals per video segment).  The diversity was lower than the average for the St. Johns River, but it was only a little lower than the values for Juniper or Gemini Springs and, actually, it was higher than the average for the Suwannee River springs.

On my first visit to DeLeon Springs in January, I heard a loud engine and, as it turned around the bend from Spring Garden Lake, I was surprised to see a float plane.  I heard a similar sound on my second trip, but instead of a plane, it was an airboat tour.  To my untrained ear, they sound about the same at a distance.

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An airboat in the run of DeLeon Springs.

 

Gemini Springs, Volusia County, revisited, May 2017

Gemini Springs seems like a good example of the opposite of Juniper Spring.  Gemini is a bit of an urban spring, surrounded by a park.  Its flow originates from two small springs that discharge into a short sandy run.  That run was dammed in the 1970s to create a large pool for swimming and, although swimming was stopped in the early 2000s, the pool is still there.  Even below the dam, the spring has a short run that flows through a wide marsh into Lake Monroe.

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Looking down from Gemini Springs run into the pool

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The dam that creates the pool at Gemini Springs.

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Above and below water views of the Gemini I.

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Above and below water views of Gemini II.

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Google Earth image of the largely urban landscape around Gemini Springs.

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The dam is visible, as is a difference in the color of the water, in this closer image from Google Earth.

The discharge of Gemini Springs is lower than any other spring that I visited; it is naturally low as the springs are small.  Although the discharge is low, the water is rather salty (conductivity = 2320 micromhos/cm); the only spring on the St. Johns River that has higher conductivity is Salt Spring (conductivity = 5800 micromhos/cm).  The nutrient concentrations, as one might expect for an urban spring, were moderately high (nitrate = 1.2 mg/L, phosphate = 0.08 mg/L).  I recorded no plants in the run except for cattails and some other emergent plants below the dam.  There was a fair amount of algae both above and below the dam.

Despite the urban setting, the low discharge, and the relatively high nutrient concentrations, I measured the second highest fish species richness at Gemini Springs of all the springs that I visited (19 species); only Volusia Blue Spring (25 species) was higher.  The fish diversity was a bit lower because diversity was fairly low above the dam, not surprisingly, but higher below the dam.  I added many species to the list in the run below the dam.  Gemini Spring also provided me with my favorite video ever.

The images were very different near Gemini I, in the pool, and below the dam.

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Sailfin mollies (Poecilia latipinna) and mosquitofish (Gambusia holbrooki) in a side pool near Gemini I.  The fish in the middle of the group of four on the right is a male molly in breeding colors.  His dorsal fin is much larger than the females’ dorsal fins.

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Exotic blue tilapia (Oreochromis aureus) in the pool above the dam.  The fish in the middle of the image just left its nest, which is the big hole on the left side of the photo.  There are also some mosquitofish up at the surface.

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Gemini Springs run in the marshy area below the dam.  This photo may not look that much clearer than the photo from the pool, but there are actually five different species in the photo: mosquitofish, sailfin mollies, bluefin killifish (Lucania goodei), least killifish (Heterandria formosa), and a Florida gar (Lepisosteus platyrhincus).  At other times in the video, there are rainwater killifish (Lucania parva), flagfish (Jordanella floridae), and largemouth bass (Micropterus salmoides).

Given that the diversity was so high below the dam and that I average the data above and below the dam to represent the entire spring (as I did for all springs), I think that the diversity of Gemini Spring would be higher if the dam were not there.

Here is my absolute favorite video from the whole survey:

A Florida gar doing a drive by of the camera.

I also saw a bunch of armored catfish (Pterygoplichthys disjunctivus or P. multiradiatus) that freaked out before I could get close to them.  Mostly I saw a poof in the fluff on the bottom of the spring run.  That fluff was thick.

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Sediment stirred up by an armored catfish freaking out.

 

 

Juniper Spring, Marion County, May 2017

I gravitate toward small, sandy spring runs with overarching tree canopy, so Juniper Spring has always been a favorite.  Like many, or perhaps most, of the big springs in Florida, the Juniper headspring was modified long ago for swimming.

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The Juniper headspring.  The vent is in the foreground of the photo.

The modification makes for a nice, easy-access swimming area, but once the run leaves the headspring area, it is unmodified and seemingly pristine.  The bottom is sandy and the water is shallow and so clear so that it almost looks more like a dry sand path rather than a spring run.

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The Juniper Spring run just below the put-in for canoes.

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Looking upstream under water at the put-in spot for canoes.

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Views of the upper run of Juniper Spring.

One of the things that I love about Juniper Spring is that it has loads of blackbanded darters (Percina nigrofasciata) in the upper part of the run.  I can watch them doing their darter business, planting themselves on the sand until they decide it’s time to move, then lifting up and floating downstream until they turn around and plant themselves again.

Blackbanded darters and shiners (Notropis sp.) working the flow just downstream from the put-in spot for the canoes in the upper reaches of the spring run.  In the video two darters inch their way up the run in the lower left quadrant.  Some other darters work their way across the run further back in the video.  They look like they are expending next to no energy to stay in place as they plant their pectoral fins in the sand.  By contrast the shiners are working hard with their tails to stay in the flow.

Like the other Ocala NF springs, the landscape around Juniper Spring is conservation land.  The spring run is so narrow that it is hard to see even on a closeup aerial shot.

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Google Earth image of the landscape around Juniper Springs.

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Closeup of the Juniper Springs landscape; the spring is barely visible in the upper right quadrant of the photo although it starts on the left side.  It is interesting how the tree cover appears much thicker around the spring run.

The discharge and conductivity of Juniper Spring are quite low compared to the other Ocala NF springs (dishcarge = 11 vs. 1070-5800 cfs, conductivity = 125 vs. 1070-5800 micromhos/cm).  The spring is a little colder (22oC vs. 24oC) and more oxygen-rich (7.6 vs. 2.8-6.2 m/L) than the other springs as well.  Although the high dissolved oxygen concentration is likely a function of the low surface to volume ratio (more of the water exposed to air) and the lack of large volumes of organic matter (bacteria breaking down organic matter use oxygen), oxygen dissolves more readily in colder water as well.

Downstream, quite a long way, the spring widens and deepens slightly.

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The water clarity in this area of the run is a bit lower, as is the flow.  The fish assemblage changes as well.

Shiners (Notropis harperi?) in the deeper and wider area of the run downstream.

Even further downstream, the overhead canopy disappears and the run acquires some deep-ish pools.

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Views of Juniper Spring run.  I believe that the last photo was taken shortly before the “rapids”.  The rapids are tiny as rapids go, but still fun.

Even further downstream just past the pull-out point for canoes, eelgrass (Vallisneria americana) or Sagittaria takes over the bottom of the run.  However, I did not catch many fish on video down here.

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Eelgrass or Sagittaria below the canoe exit for the shuttle.

It would be interesting to paddle the whole run and get a picture of the fish assemblage further downstream!

Alexander Springs, Lake County, May 2017

Rocky and complex like a sandy underwater canyon, the Alexander Springs vent is truly lovely.  On the day that I visited, there were only a few people near the vent (and only a few people in the park): three scuba divers and a free diver.  How wonderful it is to visit these springs in the off season!

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Above water view of the Alexander Springs vent.

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Underwater views of the Alexander Springs vent.

Like Silver Glen and Salt Springs, Alexander Springs is smack in the middle of the Ocala National Forest conservation lands.  It is the southernmost of the big Ocala NF springs and its long run meanders 13,000 m through the forest before entering the St. Johns River south of Lake Dexter.

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Google Earth image of the landscape around Alexander Springs.

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Closer Google Earth image of Alexander Springs.

The run is narrow and intimate feeling, with some slight braiding.

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The Alexander Springs run a short way downstream from the headspring.

Like several other of the St. Johns River springs (Salt, Silver Glen, Volusia Blue, Gemini, and to some extent, DeLeon), Alexander Springs is a bit salty (conductivity = 1070, http://www.sjrwmd.com/springs/alexander.html) due to ancient sea water that was trapped in the aquifer thousands of years ago.  The conductivity would be higher if the water that discharged from the spring were only that trapped seawater, but the seawater combines with the freshwater that recharges the aquifer continuously before it discharges.  The discharge of the spring is relatively high (100 cfs) and the spring is fairly low nutrient (nitrate = 0.55 mg/L and phosphate = 0.04 mg/L).  For comparison, the nitrate concentrations of the nutrient-rich Suwannee River springs ranged from 1.8-5.7 mg/L and the phosphate concentrations ranged from 0.03-0.08 mg/L.  Nutrient enrichment of nitrate is more common than phosphate in Florida springs because nitrate travels more readily through the soil than phosphate.  With the relatively low nutrient concentrations in Alexander Springs, I was very surprised to see dense algae just below the headspring.

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Algae blanketing the bottom of the Alexander Springs run.  It is a pretty color anyway…

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Eelgrass (Vallisneria americana) poking through the filamentous algae.

The bright green algae abated downstream and gave way to abundant eelgrass, although even here the leaves were covered a thin layer of algae.  However, the eelgrass and other vegetation provided habitat for a remarkable number of fish.

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Eelgrass waving in the flow of Alexander Springs.

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Spadderdock (Nuphar luteum) in the Alexander Springs run.  The bright yellow ball in the foreground is a spadderdock flower; the flowers do not really open like a lotus, but rather stay like a ball even when mature.

The fish species richness (total number of species) of Alexander Springs was among the highest that I measured among all the springs that I sampled (17 species vs. 25 for Volusia Blue and 19 for Gemini) and the diversity was the highest of all of the springs (2.16 vs 2.13 for Volusia Blue) despite the algae and a fair amount of silt along the banks.  There also were more of the larger fish, sunfish (Lepomis sp.), largemouth bass (Micropterus salmoides), and lake chubsuckers (Erimyzon succetta), than in any other spring that I surveyed.  At one point, there were so many fish that I had to stop the video and count frame by frame.

Largemouth bass, chubsuckers and a golden shiner or two (Notemigonus chrysoleucas) milling around in the run of Alexander Springs.

Loads of big golden shiners and a few chubsuckers in the run of Alexander Spring.

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An otherwordly shot of a chubsucker.

It is interesting how much fish vary morphologically.  A readear sunfish (Lepomis microlophus) that looked like it was missing most of its pigment roamed through the videos.  And among all of the springs, I have regularly seen largemouth bass that are stripe-less.

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Both the redear sunfish and largemouth bass in this photo look somewhat pigment-less.  What are they looking for?  Perhaps the fish exodus in the following video…

These are either some curious fish or something was behind them…

 

Wakulla and Sally Ward Springs, Wakulla County, April 2017

Wakulla Springs is, with Silver and Rainbow Springs, among the largest of Florida’s springs and probably among the largest freshwater springs in the world (~800 cfs).  Of the three, it felt the most remote and untouched to me, although they all have been touched and it’s probably busier in the summer.  The land that surrounds the springhead was sold to the state by Edward Ball in the 1960s.  He had owned the land since the 1930s and the lodge, which still hosts guests, was his personal guesthouse.  Besides leaving behind a lovely lodge for visitors, unique for a state park, Ed Ball required that use of the spring would be limited.  To this day, on the park’s land, people are only allowed in or on the spring at the headspring, where swimming is allowed, or on a tour boat which only goes down the run to about the first turn of the big spring.

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A small portion of the Wakulla Spring headspring.

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The lodge at Edward Ball Wakulla Springs State Park.

Wakulla Springs is just south of Tallahassee, but driving up to it, it feels much more remote.  The landscape around the park is a mixture of forest, low density housing, and agriculture.

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Google Earth image of the landscape around Wakulla Springs.

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A closer Google Earth image gives a better picture of the magnitude of the spring.  The tree islands are visible at this altitude, as is Sally Ward spring entering into the spring just below the headspring.

Besides a peaceful stay in a beautiful 1930s lodge with a delicious dinner and a great hike in gorgeous forest around the lodge, this trip was amazing because I was literally the only one on the water in the morning.  After the very helpful park biologist unlocked the gate to let me down to the water, I was completely alone with the big water, the trees, and the critters.

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My kayak right before I went out to work.  The platforms are part of the limited swimming area.

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Me, not believing my luck with the spring run stretching behind me…

Once I pushed away from the beach, I did a tour of the headspring.  I think that it was the deepest spring that I visited during my spring survey.  Unlike the other springs that I visited, I couldn’t even see the bottom of the vent on the video.

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These unidentified catfish look like they’re swimming down into an abyss in the Wakulla headspring.  I was impressed.

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These mullet (Mugil cephalus) also look like they’re swimming into nothingness.

I did my best to record fish at the headspring of Wakulla and I was successful along the bank, but the catfish on the edge of the vent were too deep to identify.

After looping around the headspring a couple of times, I turned down the enormous run.

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Looking down the run from the headspring.  The tour and park staff boats are visible on the right side of the photo.

The tree islands were especially beautiful and as I neared them, I discovered that they were loud with bird calls.  The park attributes the high density of birds in the park to the limited human use.  They may well be right; there were impressive numbers of birds and alligators.  I saw more alligators at Wakulla than anywhere else.

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A tree island just down from the headspring.

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Another view of tree islands.

Wakulla in the morning

If I remember correctly now, I took this photo at the first turn in the spring, as I was coming around the corner, so to speak.

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The dominant impression of this photo is the lovely old cypress, but a closer inspection reveals an egret as well.  Even the wildlife, which was abundant, seemed dwarfed here.

After paddling down past the second curve in the spring, I turned around and headed back upstream to start my shallow water bank videos.  Instead of retracing my path exactly, I went on the other side of a giant tree island.  The wind had begun to kick up and the side channel was very peaceful.

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The side channel near the headspring of Wakulla.

Although I didn’t get great videos of the vent at the headspring, the videos from the bank were good.

Bluefin killifish (Lucania goodei) and mosquitofish (Gambusia holbrooki) on the edge of the headspring.  Mosquitofish are literally everywhere and bluefins are right behind them.  These male bluefins were showing off their blue dorsal fins in a territorial display.

As is pretty obvious in the video above, there was algae at Wakulla, although I have definitely seen worse.  I went to Wakulla Spring in part because it has been held up as an example of how nutrient reduction can work.  The concentration of nitrate in the spring peaked at over 1 mg/L in 2000 or so and, through nutrient redirection, it is now down to 0.3-0.4 mg/L (http://www.dep.state.fl.us/water/watersheds/docs/bmap/Wakulla-BMAP.pdf), which is really remarkable.

Eelgrass (Vallisneria americana) or Sagittaria partially on the bottom of Wakulla Springs run.

I applaud the nutrient reductions and the commitment to restoration.  Hopefully, algae will decline over time…

Although this is a little out of order, I sampled Sally Ward Spring, which flows into Wakulla Spring, the evening before I surveyed Wakulla.  It’s a pretty little spring that actually seems to harbor more fish diversity than the big spring.

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A view looking across the headspring of Sally Ward Spring.

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A view looking down the Sally Ward Spring run.

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One of the vents of Sally Ward Spring.

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Nice largemouth bass (Micropterus salmoides) in Sally Ward Spring.

Florida gar (Lepisosteus platyrhincus), largemouth bass, and sunfish (Lepomis sp.) in Sally Ward Spring.

Turtles freaking out at my approach in Sally Ward Spring.

Salt Springs, Marion County, April 2017

Salt Springs is a beautiful collection of small, rocky vents.  Not surprisingly, given its name, Salt Springs has the highest conductivity (kind of the freshwater version of salinity) of any of the St. Johns River springs.  In fact, its conductivity is about 50 times the conductivity of Juniper Springs and at least 10 times higher than any of the Suwannee River or Santa Fe River springs.  This conductivity is still a fraction of saltwater, so the saltiness is not perceivable by taste, but it does increase the likelihood of some salt-tolerant species occurring in the spring (think blue crabs and Atlantic stingrays).

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One of several Salt Springs vents at the spring head.

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View of another of the vents.  There were lots of juvenile striped mullet (Mugil cephalus), as in this photo, swimming around the springhead.

Salt Springs sits in the heart of the Ocala National Forest; the only human inhabitants nearby are the small town of Salt Springs.  It flows down a moderately long run to the north end of Lake George.

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Google Earth image of the landscape around Salt Springs.

Just below the springhead, the run widens out into almost a lake, although it was still shallow enough to see the eelgrass or Sagittaria covering the bottom.  Like Silver Glen, it appears that boats anchor just outside the springhead, although not in the same numbers as at Silver Glen.  Probably the length of the run reduces the number of boaters; two of the three boats that I saw that day were fishing.

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A view looking back at the springhead with a boat parked just outside the park.

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The “lake” in the run of Salt Spring.  The run narrows again at the back of the photo.

The day that I went out, it was fairly windy, so after paddling hard down the run (but upwind), I eventually took refuge in a side creek that I wanted to explore.  I didn’t find many fish in the side creek, but it was lovely and peaceful.

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This side creek to the main Salt Springs run seemed to have no wind at all…

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Another view of the side creek of Salt Spring, just before it became impassible.  I was looking for another spring at its source, but I didn’t make it, so I never found out whether there was one.

Salt Springs also has a moderately high discharge (80 cfs), only slightly lower than Silver Glen Springs and about half of the discharge of Volusia Blue Spring.  It also has fairly good dissolved oxygen for a Florida spring (4-6 mg/L as opposed to 0.1-1.5 mg/L for Volusia Blue) and low nutrient concentrations (0.1 mg/L for nitrate and 0.02 mg/L for phosphate).  Given that some of the Suwannee River springs had nitrate concentrations on the order of 2-5 mg/L, the nutrient concentrations for Salt Springs look good.  I would predict low nutrient concentrations, given the lack of farmland or dense human development around the spring, so I was very surprised by the abundant algae and murky water in the run below the headspring.  I’m still puzzling that one out, as are most people who work on springs, I believe.

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Algae on the bottom of Salt Spring, just below the springhead.  It was so thick that the eelgrass (Valisneria americana) or Sagittaria was just barely poking out through it.  I was surprised that the plants were even still alive.

Downstream the algae abated quite a bit, but it was hard to see and there was definitely algae on the plants.  Perhaps the wind contributed to the murk.

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Eelgrass or Sagittaria on the bottom of Salt Springs run in the “lake” area.

Despite the algae and the turbidity, the diversity of fish was high for Salt Spring.  Both the diversity and the absolute counts of fish probably would have been even higher had I been able to see better.  The St. Johns River springs, generally, have higher diversity than the Suwannee and Santa Fe River springs, by my estimation.  There are a number of possible explanations for the high diversity, the length of the springs and the high conductivity being only two possibilities.

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Spotted (Lepomis punctatus) and bluegill (Lepomis macrochirus) sunfish near the springhead.

A couple of sunfish and shiners (Notropis sp.) in the run a little below the headspring.  Water clarity made fish counting a challenge on that windy day.  It’s interesting that the entire substrate of the bottom is moving through the entire video.

Salt Spring is a beautiful place, but I’m left with this mystery: why so much algae and suspended stuff creating murk?

 

 

Silver Glen Springs, Marion County, April 2017

When I visited Silver Glen Springs this past spring, I had not been there in a couple of years, I think, and I had forgotten the gorgeous blue of the headspring.  It was truly stunning.

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The main vent of Silver Glen Springs.

The giant shoal of sunshine bass (Morone chrysops x saxatilis) in the main vent and the smaller shoal of sunshine and striped bass (Morone saxatilis) in the vent on the side of the headspring (in the roped off conservation area) also were magnificent.  These fish are thought to use the spring as a cool water refuge during warm periods (Jay Holder, FWC).  They do not congregate in other springs, some of which have oxygen concentrations too low to support them, so this boiling mass of fish is unique.

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The shoal of sunshine bass from the surface.

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The same shoal under water.  I have been told to ID sunshine bass by the broken line of dots that make up the stripes down their sides, among other characters.

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The shoal of bass (probably sunshine and striped) in the side vent.

Up until mid-April, the only St. Johns River springs that I had visited were Wekiwa and Rock Spring, both of which have fairly high nitrate concentrations, and Volusia Blue Spring, but all three of these springs are closer to dense human populations than the Ocala Springs.  With this trip to Silver Glen, I began to contemplate the Ocala Springs and to have a wider view of St. Johns River springs generally.  Silver Glen Springs is smack in the middle of a large conservation area, the Ocala National Forest, and probably as a result, it has the lowest nitrate concentration of any spring that I visited (0.05 mg/L, http://www.sjrwmd.com/springs/silverglen.html).  By contrast, the Suwannee River springs ranged from 1.0-5.7 mg/L; the highest concentration, in Fanning Springs, was clearly two orders of magnitude higher than Silver Glen.

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Google Earth image of the landscape around Silver Glen Springs.  Much of the landscape around the spring is managed forest.

The low nitrate (and phosphate) concentrations are a little misleading, however, in the context of human impact on the spring.  The run of Silver Glen is very short and somewhat wide and it flows into Lake George.  Boaters regularly come up the spring from the lake and anchor in the middle of the run (and sit on lawn chairs in the water), producing a white sand streak down its center just below the headspring.

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The Silver Glen Springs run.  The headspring is on the left side of the image and the confluence of the spring with Lake George is on the right side.  The light area with boats anchored is bare sand; most of the rest of the run is covered with eelgrass (Valisneria americana) or Sagittaria kurziana.

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Silver Glen run looking up at the headspring.  Several anchored boats are visible in the distance.

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A large pontoon boat with two skiffs anchored near shore.

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The entrance of Silver Glen Springs into Lake George.

Despite the good coverage of plants over much of the run, I was surprised by the density of algae at the headspring and the blanket of algae on the plants in the run.

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The headspring of Silver Glen was ringed by algae.  In the photo, there are swimmers in the background, free diving into the vent, and striped mullet (Mugil cephalus) feeding in the algae on the right side of the photo.

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The algae was just as thick on the opposite side of the headspring; a lovely little male rainwater killifish (Lucania parva) stood out nicely against the algae.

Floating down Silver Glen run.  The plants look fuzzy because they were covered in algae.  The water clarity was not particularly high either, so the striped mullet in the background are hazy in the video.

The substrate near the bank was covered with material; someone suggested to me recently that it might be mineral, but it looks organic to me.  If you look at the video, the whole bottom is gently moving the entire time.  I am not sure what a thick layer of moving material does to fish; it might be disruptive or it might provide lots of invertebrates to eat.  There’s a question.

Shifting substrate along the bank of Silver Glen run.  The spotted sunfish (Lepomis punctatus) and bluegill (Lepomis macrochirus) in the area do not look distressed…

In the end, the total number of large fish that I observed in the middle of the run was the highest of any of the springs that I surveyed, due primarily to a million striped mullet (not literally).  The diversity also was fairly high, but the number of smaller fish near the bank was on the low side.  Perhaps some of the generally high diversity of the St. Johns River springs is related to their high conductivity (a measure of ion concentrations in the water, kind of like the freshwater version of salinity).  The conductivity of five of the nine St. Johns River springs that I surveyed was over 1000 micromhos/cm (www.sjrwmd.gov) as compared to 100-500 micromhos/cm for the other springs on the St. Johns River, the Suwannee River springs, and the Santa Fe springs.  The dissolved oxygen concentrations also were quite high compared to many Florida springs (~5 mg/L); the high dissolved oxygen also could contribute to the high diversity.

Above the water, the algae and moving sediment were not always obvious, so it was easy to get lost in a lovely paddle.  Surprisingly, I particularly enjoyed photographing the buoys, which I thought looked like large, red crayons.

silver glen buoysilver glen run with buoy