a geological perspective on the preservation and
TRANSCRIPT
A geological perspective on the preservation and restoration of
Florida’s coral reefs
Lauren T. Toth, Ilsa B. Kuffner, & Anastasios StathakopoulosU.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
U.S. Department of the InteriorU.S. Geological Survey
Habitat
Islamorada, FL Keys, after Hurricane Irma
Shoreline protection Tourism
$375 billion/yr to Florida’s economy (NOAA)
1971
Photos courtesy of Gene Shinn
1998
1971 1988
2004
Photos courtesy of Gene ShinnGrecian Rocks, Florida Keys
Hen & Chickens Reef, FL Keys
1998 elevation
Reef erosion is becoming a dominant process
2015 elevation
Reef erosion rate:-5.5 ± 3.2 mm yr-1
Kuffner, Toth, et al. in review
Harold Hudson’s “monuments” (n = 28) used to measure reef
erosion (est. 1998)One of the only direct measurements of
reef erosion rate in Florida
Gene Shinn
USGS Core Archive: http://olga.er.usgs.gov/coreviewer/
The past is the key to the future
185 radiometric ages from 46 cores from
throughout the Florida Keys
Coral reef development in south Florida
Toth et al. 2018. Global Change Biology
Hubbard et al. 2005, 2013; Macintyre and Glynn 1976; Macintyre 1977; Macintyre et al. 1985; Gischler and Hudson 2004
Hubbard et al. 2005, 2013; Macintyre and Glynn 1976; Macintyre 1977; Macintyre et al. 1985; Gischler and Hudson 2004
Anthropogenic warming
Geological shutdown of Florida’s coral reefs
Toth et al. 2018. Global Change Biology
Florida’s reefs have grown little in the last 3000 years
Lirman et al. 2011. PLoS One
Cold-water coral mortality
Timing of reef shutdown
Florida Bay
Florida Bay flooded and was connected to the reefs of the
Florida Keys 8000–5500 years ago
Differences in duration of reef
development explain spatial variability in
reef thickness
Reef accretion Reef erosion
Holocene Thermal Maximum Anthropogenic warmingClimatic cooling
Geological shutdown of Florida’s coral reefs
Toth et al. 2018. Global Change Biology
Cold-water coral mortality
Global tem
perature anomaly (°C)
0.5
-0.5
0
Reefs influenced by Florida Bay stop growing
Acropora palmata
Orbicellaspp.
Brain corals
Porites astreoides
Siderastrea siderea
Other corals
Geological reef frameworkAcropora palmata
Orbicellaspp.
Brain corals
Porites astreoides
Siderastrea siderea
Other corals
Modern ReefsChanges in reef composition
Collaborators: Rob Ruzicka and Mike Colella (FWRI, FL FWCC)http://myfwc.com/research/habitat/coral/cremp/Toth et al. in press. Ecology
>90% Holocene
reef framework
>60% cover on modern
reefs
Acropora palmata
Orbicellaspp.
Brain corals
Porites astreoides
Siderastrea siderea
Other corals
Middle Holocene Reefs
Optimizing coral restoration
• Acropora cervicornis only accounts for 2% of the reef framework in our cores from the Florida Keys
• Does not build lasting reef structure
A geological perspective on coral-reef management• Changing climate and the influence of Florida Bay
have suppressed reef growth in Florida has been suppressed for ~3000 years
• The outcomes of coral-reef management and restoration can be optimized by prioritizing efforts that promote reef growth and mitigate reef erosion
• Preserving the geologic structures that remain is a worthy management goal
• Focus on restoration of reef-building corals such as Acropora palmata and Orbicella spp.
Spatial patterns of reef development
50 km
No significant difference in reef accretion among sectors
(F5,44=0.09, p=0.99)
Reef
acc
retio
n (m
/100
0 y)
Geological senescence of Florida’s coral reefs
3
2
1
0
Reef
acc
retio
n ra
te (m
/ky)
The carbonate budget of a coral reefCarbonate Production(calcification x coral cover x rugosity)
Bioerosion(+ sediment export and dissolution)
P.W. Glynn
1971
E.A. Shinn
Reef accretion
The carbonate budget of a coral reefCarbonate Production(calcification x coral cover x rugosity)
P.W. GlynnE.A. Shinn
2001
Reef erosion
Bioerosion(+ sediment export and dissolution)
The carbonate budget of a coral reefCarbonate Production(calcification x coral cover x rugosity)
E.A. Shinn
2001
Reef erosion
1971
E.A. Shinn P.W. Glynn
Bioerosion(+ sediment export and dissolution)
Kim Yates, Dave Zawada, et al.2017 Biogeosciences
Large-scale trends in reef erosion since the 1930s
Maui, Hawaii
Upper & LowerFlorida Keys
St. Thomas, USVI
Buck IslandSt. Croix, USVI
Pacific Ocean
Atlantic Ocean
CaribbeanSea
-38 Mm3
-6 Mm3-81 Mm3
-22 Mm3
-3 Mm3
Empire State Building Volume
= 1 Mm3
-7.97 - -4.00-3.99 - -3.00-2.99 - -2.00-1.99 - -1.00-0.99 - -0.50-0.49 – 0.000.01 – 0.500.51 – 1.001.01 – 2.002.01 – 3.003.01 – 5.25
Seafloor Elevation Change (m)
-0.4 m
-0.3 m
+0.1 m
Seafloor Erosion
Seafloor AccretionKilomete
rs