Tallahassee Democrat

July 31, 2015

By Will Sheftall

Exploring seagrass bed nurseries in St. Joe Bay.
Photo by Rosalyn Kilcollins.

Maybe you’ve lived here all your life, and your knowledge of Florida’s “Capital Coast” has come about through experiences. Do you remember driving scenic US 98 to eat at seafood restaurants? Chaperoning a school field trip to Gulf Specimen Marine Lab’s aquaria? Taking house guests to see the St. Marks Lighthouse, plus ducks and eagles at the Wildlife Refuge pools? Perhaps you’re a frequent beach bum at St. George or Cape San Blas, love the dunes and have seen the crawl track left by a nesting sea turtle.

Many of us, when we gain familiarity with a place over a lifetime, may have the sense that we really “know” the locale very well. Actually, we may know less about “why it’s what it is” than a vacationer with a bent to explore the region’s natural history. Heck, maybe even less than a casual ecotourist out with a knowledgeable Green Guide!

To see how well you know your coast, here’s a little quiz for fun. Give it your best shot, then look at the answers below to see how you did.

1. Why aren’t there any barrier islands east of Dog Island?
2. Why aren’t there high dunes on the barrier islands east of Cape San Blas?
3. What two estuaries receive all the water draining from land within Leon County?
4. Which estuary receives the greater amount of runoff and groundwater draining from the Leon County landscape?
5. Without an oyster industry in Apalachee Bay, is freshwater inflow important to that bay’s estuarine system like it is for Apalachicola Bay?
6. How are we fortunate to have so much “hard bottom” offshore, which provides great habitat for marine species like grouper and snapper, and makes fishing our coast so superbly diverse?
7. Will dunes covered by sea oats and protected from development (via setbacks) and foot traffic (via walk-overs) hold against major storms and even hurricanes?
8. Are seawalls a good way to stop beach erosion on barrier islands?

If you want to know more about the “hows and whys” of Florida’s “Capital Coast,” consider enrolling in the upcoming Florida Master Naturalist course on “Coastal Systems.” It’s being offered by University of Florida IFAS Extension Leon County and the Tallahassee Museum. Classes start August 14^th.

The course also will cover the fascinating animals and plants that inhabit all of Florida’s coastal habitats. Check out the schedule and register on-line by August 10^th at http://conference.ifas.ufl.edu/fmnp/ (click on “Coastal Systems” then “Leon County”). Reward yourself with the good company of interesting and intrepid naturalists as you see cool places and learn new things about the coast you’ve known so long!

Answers:

1. The wide and shallow, gently sloping Continental Shelf off Apalachee Bay makes ours a low-energy coastline. High wave energy is required to form big sandbars and mold them into barrier islands during storms.
2. Winds onshore or shore-parallel pile dry sand into dunes. High dunes require a large amount of sand, which is the limiting factor along our coast east of the Cape.
3. Apalachee Bay and Ochlockonee Bay.
4. Apalachee Bay receives water from the St. Marks River and its tributary the Wakulla, which together drain away most of Leon County’s water, through sinkhole lakes and disappearing streams. The Ochlockonee River has only relatively short tributaries in Leon County.
5. Yes. Seasonal high flows of freshwater from our few rivers and many coastal creeks flush nutrients from leaves and wood recycled in swamps. These pulses fertilize salt marshes and offshore seagrass meadows, which are critical for sustaining our coast’s abundant marine life up the food chain to most saltwater fishes.
6. Limestone that lies close to the surface in eastern Wakulla through Taylor counties continues offshore. It’s the same underlying geology we see on land near today’s coast, only lower in elevation and now drowned. It was the coast inhabited by First Floridians during the last Ice Age, before sea level rose in response to glacial melting.
7. Dune blow-outs are less likely if there are no weak points in their topography and vegetation. However, dunes on barrier islands protect the mainland from battering waves by absorbing the brunt of a storm’s wave energy, which is dissipated by “doing work” – moving sand around. Dunes are functionally sacrificial, but also renewable between storms.
8. Actually, it’s coastal land that erodes, not beaches. A beach is the sloping intertidal zone of a high energy shoreline. The beach advances, the beach retreats. Seawalls destroy the migrating beach in order to protect coastal land from this natural process. Coastal landscapes must absorb energy and be reconfigured naturally if landforms such as barrier islands and beaches are to sustain themselves as sea level rises. Sea-walled islands will be drowned unless elevated by fill.

Will Sheftall is an Extension Agent with Leon County/University of Florida IFAS Extension. For gardening questions, email us at Ask-A-Mastergardener@leoncountyfl.gov

Sidebar Question:

How many paddling trails are there in the estuarine waters of Florida’s “Capital Coast?”

Sidebar Answer:

Four. They are 1) Apalachee Bay Maritime Heritage Paddling Trail (download maps at http://www.visitwakulla.com/Things-to-Do/Apalachee-Bay-Maritime-Heritage-Paddling-Trail-System), 2) Florida Circumnavigational Saltwater Paddling Trail, Segment 5 – Crooked River to St. Marks Refuge (download maps at http://www.dep.state.fl.us/gwt/paddling/segments/Segment5/Segment5.htm), 3) Dead River Sopchoppy Loop Paddling Trail and 4) Bear Creek Paddling Trail (maps for these two 7.5-mile loop trails are available at Ochlockonee River State Park).

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